Patent Publication Number: US-11387280-B2

Title: Light-emitting device and electronic device

Description:
This application is a continuation of U.S. application Ser. No. 16/265,203, filed on Feb. 1, 2019 which is a continuation of U.S. application Ser. No. 15/900,021, filed on Feb. 20, 2018 (now U.S. Pat. No. 10,199,436 issued Feb. 5, 2019) which is a continuation of U.S. application Ser. No. 15/598,537, filed on May 18, 2017 (now U.S. Pat. No. 9,905,617 issued Feb. 27, 2018), which are all incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     One embodiment of the present invention relates to a light-emitting element, a light-emitting device, and an electronic device. Note that one embodiment of the present invention is not limited thereto. That is, one embodiment of the present invention relates to an object, a method, a manufacturing method, or a driving method. One embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter. As specific examples, a semiconductor device, a display device, a liquid crystal display device, a lighting device, and the like can be given. 
     BACKGROUND ART 
     A light-emitting element including an EL layer between a pair of electrodes (also referred to as an organic EL element) has characteristics such as thinness, light weight, high-speed response to input signals, and low power consumption; thus, a display including such a light-emitting element has attracted attention as a next-generation flat panel display. 
     In a light-emitting element, voltage application between a pair of electrodes causes, in an EL layer, recombination of electrons and holes injected from the electrodes, which brings a light-emitting substance (organic compound) contained in the EL layer into an excited state. Light is emitted when the light-emitting substance returns to the ground state from the excited state. The excited state can be a singlet excited state (S*) or a triplet excited state (T*). Light emission from a singlet excited state is referred to as fluorescence, and light emission from a triplet excited state is referred to as phosphorescence. The statistical generation ratio of S* to T* in the light-emitting element is considered to be 1:3. Since the spectrum of light emitted from a light-emitting substance depends on the light-emitting substance, the use of different types of organic compounds as light-emitting substances makes it possible to obtain light-emitting elements which exhibit various colors. 
     To display a full-color image on a display, for example, light-emitting elements of at least three colors of red, green, and blue are necessary. Furthermore, the light-emitting elements are required to consume low power. 
     Examples of specific methods for displaying a full-color image are as follows: so-called side-by-side patterning in which light-emitting elements that emit light with different colors are separately formed; a white-color filter method in which a white light-emitting element is used in combination with a color filter; and a color conversion method in which a light-emitting element that emits monochromatic light, such as a blue light-emitting element, is used in combination with a color conversion filter. Each of the methods has advantages and disadvantages. 
     REFERENCE 
     Patent Document 
     [Patent Document 1] Japanese Published Patent Application No. 2007-053090 
     DISCLOSURE OF INVENTION 
     Compared with side-by-side patterning, a white-color filter method, which is a specific method for displaying a full-color image, facilitates high resolution because a plurality of light-emitting elements share one EL layer, and is suitable particularly for the market of displays. 
     Since light-emitting elements emitting red light, green light, and blue light utilize white light emitted from a common EL layer in a white-color filter method, a display with a wide color gamut can be obtained by setting the chromaticities (x, y) of emission colors of the light-emitting elements in desired ranges. 
     Thus, in one embodiment of the present invention, a light-emitting device that can display an image with a wide color gamut can be provided. In one embodiment of the present invention, a novel light-emitting element can be provided. In one embodiment of the present invention, a light-emitting element with high color purity can be provided. 
     Note that the description of these objects does not preclude the existence of other objects. In one embodiment of the present invention, there is no need to achieve all the objects. Other objects will be apparent from and can be derived from the description of the specification, the drawings, the claims, and the like. 
     One embodiment of the present invention is a light-emitting device including a plurality of light-emitting elements each of which includes an EL layer between a pair of electrodes. Light emitted from a first light-emitting element has, on CIE1931 chromaticity coordinates (x, y) (hereinafter, simply referred to as chromaticity coordinates (x, y)), a chromaticity x of greater than 0.680 and less than or equal to 0.720 and a chromaticity y of greater than or equal to 0.260 and less than or equal to 0.320, light emitted from a second light-emitting element has a chromaticity x of greater than or equal to 0.130 and less than or equal to 0.250 and a chromaticity y of greater than 0.710 and less than or equal to 0.810, and light emitted from a third light-emitting element has a chromaticity x of greater than or equal to 0.120 and less than or equal to 0.170 and a chromaticity y of greater than or equal to 0.020 and less than 0.060. 
     Another embodiment of the present invention is a light-emitting device including a plurality of light-emitting elements each of which includes an EL layer between a reflective electrode and a transflective electrode. Light emitted from a first light-emitting element has, on chromaticity coordinates (x, y), a chromaticity x of greater than 0.680 and less than or equal to 0.720 and a chromaticity y of greater than or equal to 0.260 and less than or equal to 0.320, light emitted from a second light-emitting element has a chromaticity x of greater than or equal to 0.130 and less than or equal to 0.250 and a chromaticity y of greater than 0.710 and less than or equal to 0.810, and light emitted from a third light-emitting element has a chromaticity x of greater than or equal to 0.120 and less than or equal to 0.170 and a chromaticity y of greater than or equal to 0.020 and less than 0.060. 
     Another embodiment of the present invention is a light-emitting device including a plurality of light-emitting elements each of which includes an EL layer between a pair of electrodes. Light obtained from a first light-emitting element through a first color filter has, on CIE1931 chromaticity coordinates, a chromaticity x of greater than 0.680 and less than or equal to 0.720 and a chromaticity y of greater than or equal to 0.260 and less than or equal to 0.320, light obtained from a second light-emitting element through a second color filter has, on the CIE1931 chromaticity coordinates, a chromaticity x of greater than or equal to 0.130 and less than or equal to 0.250 and a chromaticity y of greater than 0.710 and less than or equal to 0.810, and light obtained from a third light-emitting element through a third color filter has, on the CIE1931 chromaticity coordinates, a chromaticity x of greater than or equal to 0.120 and less than or equal to 0.170 and a chromaticity y of greater than or equal to 0.020 and less than 0.060. 
     Another embodiment of the present invention is a light-emitting device including a plurality of light-emitting elements each of which includes an EL layer between a reflective electrode and a transflective electrode. Light obtained from a first light-emitting element through a first color filter has, on CIE1931 chromaticity coordinates, a chromaticity x of greater than 0.680 and less than or equal to 0.720 and a chromaticity y of greater than or equal to 0.260 and less than or equal to 0.320, light obtained from a second light-emitting element through a second color filter has, on the CIE1931 chromaticity coordinates, a chromaticity x of greater than or equal to 0.130 and less than or equal to 0.250 and a chromaticity y of greater than 0.710 and less than or equal to 0.810, and light obtained from a third light-emitting element through a third color filter has, on the CIE1931 chromaticity coordinates, a chromaticity x of greater than or equal to 0.120 and less than or equal to 0.170 and a chromaticity y of greater than or equal to 0.020 and less than 0.060. 
     In any of the above structures, the EL layers included in the first light-emitting element, the second light-emitting element, and the third light-emitting element are preferably EL layers that emit white light and that are formed using the same material. Each of the EL layers includes at least a light-emitting layer. A plurality of EL layers may be included in each light-emitting element, and the EL layers may be stacked with a charge generation layer positioned therebetween. 
     Another embodiment of the present invention is a light-emitting device including a first light-emitting element, a second light-emitting element, and a third light-emitting element each of which includes an EL layer between a pair of electrodes. The EL layers emit white light. Light obtained from the first light-emitting element through a first color filter has, on CIE1931 chromaticity coordinates, a chromaticity x of greater than 0.680 and less than or equal to 0.720 and a chromaticity y of greater than or equal to 0.260 and less than or equal to 0.320, light obtained from the second light-emitting element through a second color filter has, on the CIE1931 chromaticity coordinates, a chromaticity x of greater than or equal to 0.130 and less than or equal to 0.250 and a chromaticity y of greater than 0.710 and less than or equal to 0.810, and light obtained from the third light-emitting element through a third color filter has, on the CIE1931 chromaticity coordinates, a chromaticity x of greater than or equal to 0.120 and less than or equal to 0.170 and a chromaticity y of greater than or equal to 0.020 and less than 0.060. 
     To extract light with different colors efficiently from the EL layers that emit white light in the light-emitting elements, optical path lengths between the pair of electrodes are preferably adjusted depending on the emission color to form what is called a microcavity structure. 
     Another embodiment of the present invention is a light-emitting device including a first light-emitting element, a second light-emitting element, and a third light-emitting element each of which includes an EL layer between a reflective electrode and a transflective electrode. The EL layers emit white light. Light obtained from the first light-emitting element through a first color filter has, on CIE1931 chromaticity coordinates, a chromaticity x of greater than 0.680 and less than or equal to 0.720 and a chromaticity y of greater than or equal to 0.260 and less than or equal to 0.320, light obtained from the second light-emitting element through a second color filter has, on the CIE1931 chromaticity coordinates, a chromaticity x of greater than or equal to 0.130 and less than or equal to 0.250 and a chromaticity y of greater than 0.710 and less than or equal to 0.810, and light obtained from the third light-emitting element through a third color filter has, on the CIE1931 chromaticity coordinates, a chromaticity x of greater than or equal to 0.120 and less than or equal to 0.170 and a chromaticity y of greater than or equal to 0.020 and less than 0.060. 
     Another embodiment of the present invention is a light-emitting device including a first light-emitting element, a second light-emitting element, and a third light-emitting element each of which includes an EL layer between a pair of electrodes. Each of the EL layers emits white light and includes a first EL layer and a second EL layer that are stacked with a charge generation layer positioned therebetween. The first EL layer contains a red light-emitting substance and a green light-emitting substance. The second EL layer contains a blue light-emitting substance. Light obtained from the first light-emitting element through a first color filter has, on CIE1931 chromaticity coordinates, a chromaticity x of greater than 0.680 and less than or equal to 0.720 and a chromaticity y of greater than or equal to 0.260 and less than or equal to 0.320, light obtained from the second light-emitting element through a second color filter has, on the CIE1931 chromaticity coordinates, a chromaticity x of greater than or equal to 0.130 and less than or equal to 0.250 and a chromaticity y of greater than 0.710 and less than or equal to 0.810, and light obtained from the third light-emitting element through a third color filter has, on the CIE1931 chromaticity coordinates, a chromaticity x of greater than or equal to 0.120 and less than or equal to 0.170 and a chromaticity y of greater than or equal to 0.020 and less than 0.060. 
     Another embodiment of the present invention is a light-emitting device including a first light-emitting element, a second light-emitting element, and a third light-emitting element each of which includes an EL layer between a reflective electrode and a transflective electrode. Each of the EL layers emits white light and includes a first EL layer and a second EL layer that are stacked with a charge generation layer positioned therebetween. The first EL layer contains a red light-emitting substance and a green light-emitting substance. The second EL layer contains a blue light-emitting substance. Light obtained from the first light-emitting element through a first color filter has, on CIE1931 chromaticity coordinates, a chromaticity x of greater than 0.680 and less than or equal to 0.720 and a chromaticity y of greater than or equal to 0.260 and less than or equal to 0.320, light obtained from the second light-emitting element through a second color filter has, on the CIE1931 chromaticity coordinates, a chromaticity x of greater than or equal to 0.130 and less than or equal to 0.250 and a chromaticity y of greater than 0.710 and less than or equal to 0.810, and light obtained from the third light-emitting element through a third color filter has, on the CIE1931 chromaticity coordinates, a chromaticity x of greater than or equal to 0.120 and less than or equal to 0.170 and a chromaticity y of greater than or equal to 0.020 and less than 0.060. 
     In any of the structures including the reflective electrode and the transflective electrode, an optical path length between the reflective electrode and the transflective electrode in the first light-emitting element may be set so that emission intensity of red light can be increased. An optical path length between the reflective electrode and the transflective electrode in the second light-emitting element may be set so that emission intensity of green light may be increased. An optical path length between the reflective electrode and the transflective electrode in the third light-emitting element may be set so that emission intensity of blue light may be increased. 
     In any of the structures, the first color filter may have a 600-nm light transmittance of less than or equal to 60% and a 650-nm light transmittance of greater than or equal to 70%. The second color filter may have a 480-nm light transmittance of less than or equal to 60%, a 580-nm light transmittance of less than or equal to 60%, and a 530-nm light transmittance of greater than or equal to 70%. The third color filter may have a 510-nm light transmittance of less than or equal to 60% and a 450-nm light transmittance of greater than or equal to 70%. 
     In any of the structures, the light obtained from the first light-emitting element through the first color filter may have an emission spectrum whose peak value is within a range from 620 nm to 680 nm. 
     Another embodiment of the present invention is an electronic device that includes the light-emitting device of one embodiment of the present invention and an operation key, a speaker, a microphone, or an external connection portion. 
     One embodiment of the present invention includes, in its category, in addition to a light-emitting device including a light-emitting element, an electronic device including a light-emitting element or a light-emitting device (specifically, an electronic device including a light-emitting element or a light-emitting device and a connection terminal or an operation key) and a lighting device including a light-emitting element or a light-emitting device (specifically, a lighting device including a light-emitting element or a light-emitting device and a housing). Accordingly, a light-emitting device in this specification means an image display device or a light source (including a lighting device). Furthermore, a light-emitting device includes the following modules in its category: a module in which a connector such as a flexible printed circuit (FPC) or a tape carrier package (TCP) is attached to a light-emitting device; a module having a TCP whose end is provided with a printed wiring board; and a module in which an integrated circuit (IC) is directly mounted on a light-emitting element by a chip on glass (COG) method. 
     One embodiment of the present invention can provide a light-emitting device that can display an image with a wide color gamut. One embodiment of the present invention can provide a novel light-emitting element. One embodiment of the present invention can provide a light-emitting element with high color purity. One embodiment of the present invention can provide a light-emitting device with high color reproducibility. One embodiment of the present invention can provide an electronic device including a display portion with high color reproducibility. 
     Note that the description of these effects does not preclude the existence of other effects. One embodiment of the present invention does not necessarily have all the effects listed above. Other effects will be apparent from and can be derived from the description of the specification, the drawings, the claims, and the like. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIGS. 1A to 1C  illustrate light-emitting devices of one embodiment of the present invention. 
         FIGS. 2A to 2D  each illustrate a structure of a light-emitting element. 
         FIGS. 3A and 3B  illustrate a light-emitting device. 
         FIGS. 4A and 4B  illustrate a light-emitting device. 
         FIGS. 5A, 5B, 5C, 5D, 5D ′- 1 , and  5 D′- 2  illustrate electronic devices. 
         FIGS. 6A to 6C  illustrate an electronic device. 
         FIGS. 7A and 7B  illustrate an automobile. 
         FIGS. 8A to 8D  each illustrate a lighting device. 
         FIG. 9  illustrates lighting devices. 
         FIGS. 10A and 10B  illustrate an example of a touch panel. 
         FIGS. 11A and 11B  illustrate an example of a touch panel. 
         FIGS. 12A and 12B  illustrate an example of a touch panel. 
         FIGS. 13A and 13B  are a block diagram and a timing chart of a touch sensor. 
         FIG. 14  is a circuit diagram of a touch sensor. 
         FIGS. 15A ,  15 B 1 , and  15 B 2  illustrate block diagrams of display devices. 
         FIG. 16  illustrates a circuit configuration of a display device. 
         FIG. 17  illustrates a cross-sectional structure of a display device. 
         FIG. 18  illustrates a light-emitting element. 
         FIG. 19  shows the luminance-current density characteristics of light-emitting elements  1  to  4 . 
         FIG. 20  shows the luminance-voltage characteristics of the light-emitting elements  1  to  4 . 
         FIG. 21  shows the current efficiency-luminance characteristics of the light-emitting elements  1  to  4 . 
         FIG. 22  shows the current-voltage characteristics of the light-emitting elements  1  to  4 . 
         FIG. 23  shows the emission spectra of the light-emitting elements  1  to  4 . 
         FIG. 24  shows the transmission spectra of color filters. 
         FIG. 25  shows the luminance-current density characteristics of light-emitting elements  5  to  8 . 
         FIG. 26  shows the luminance-voltage characteristics of the light-emitting elements  5  to  8 . 
         FIG. 27  shows the current efficiency-luminance characteristics of the light-emitting elements  5  to  8 . 
         FIG. 28  shows the current-voltage characteristics of the light-emitting elements  5  to  8 . 
         FIG. 29  shows the emission spectra of the light-emitting elements  5  to  8 . 
         FIG. 30  illustrates a light-emitting element. 
         FIG. 31  shows the luminance-current density characteristics of light-emitting elements  9  to  11 . 
         FIG. 32  shows the luminance-voltage characteristics of the light-emitting elements  9  to  11 . 
         FIG. 33  shows the current efficiency-luminance characteristics of the light-emitting elements  9  to  11 . 
         FIG. 34  shows the current-voltage characteristics of the light-emitting elements  9  to  11 . 
         FIG. 35  shows the emission spectra of the light-emitting elements  9  to  11 . 
         FIG. 36  shows the CIE1931 chromaticity coordinates (x,y chromaticity coordinates). 
         FIG. 37  shows the CIE1976 chromaticity coordinates (u′,v′ chromaticity coordinates). 
         FIG. 38  shows the luminance-current density characteristics of light-emitting elements. 
         FIG. 39  shows the luminance-voltage characteristics of light-emitting elements. 
         FIG. 40  shows the current efficiency-luminance characteristics of light-emitting elements. 
         FIG. 41  shows the current-voltage characteristics of light-emitting elements. 
         FIG. 42  shows the emission spectra of light-emitting elements. 
         FIG. 43  shows the reliability of light-emitting elements. 
         FIG. 44  shows the emission spectra of light-emitting elements. 
         FIG. 45  shows the CIE1931 chromaticity coordinates (x,y chromaticity coordinates). 
         FIG. 46  shows the relationships between external quantum efficiency and current density. 
         FIG. 47  shows the results of driving tests (25° C.) of light-emitting elements. 
         FIG. 48  shows the results of driving tests (85° C.) of light-emitting elements. 
         FIG. 49  shows the results of high-temperature preservation tests of a light-emitting element. 
         FIG. 50  shows the emission spectra of light-emitting elements. 
         FIG. 51  shows the relationships between external quantum efficiency and luminance. 
         FIG. 52  shows the results of driving tests (25° C.) of light-emitting elements. 
         FIG. 53  shows the results of driving tests (85° C.) of light-emitting elements. 
         FIG. 54  shows the results of high-temperature preservation tests of a light-emitting element. 
         FIG. 55  shows the CIE1976 chromaticity coordinates (u′,v′ chromaticity coordinates). 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the following description, and the mode and details can be variously changed unless departing from the scope and spirit of the present invention. Thus, the present invention should not be construed as being limited to the description in the following embodiments. 
     Note that the position, the size, the range, or the like of each component illustrated in the drawings and the like are not accurately represented in some cases for easy understanding. Therefore, the disclosed invention is not necessarily limited to the position, size, range, or the like as disclosed in the drawings and the like. 
     In the description of structures of the present invention in this specification and the like with reference to the drawings, the same components in different drawings are denoted by the same reference numeral. 
     Embodiment 1 
     In this embodiment, light-emitting devices of one embodiment of the present invention will be described with reference to  FIGS. 1A and 1B . 
     A light-emitting device illustrated in  FIG. 1A  includes a first light-emitting element  105 R, a second light-emitting element  105 G, and a third light-emitting element  105 B. The first light-emitting element  105 R includes a first electrode  101 , an EL layer  103 R, and a second electrode  102 . The second light-emitting element  105 G includes the first electrode  101 , an EL layer  103 G, and the second electrode  102 . The third light-emitting element  105 B includes the first electrode  101 , an EL layer  103 B, and the second electrode  102 . Note that the EL layers ( 103 R,  103 G, and  103 B) included in the light-emitting elements contain different materials partly or entirely and are formed by a separate coloring method. This means that, for example, the EL layer  103 R can be an EL layer that emits red light, the EL layer  103 G can be an EL layer that emits green light, and the EL layer  103 B can be an EL layer that emits blue light. 
     At least one of the electrodes (in the cases of  FIGS. 1A and 1B , the second electrode  102  in the arrow direction in which light is emitted from the EL layer) included in each of the light-emitting elements is preferably formed using a light-transmitting electrode material. 
     A light-emitting device illustrated in  FIG. 1B  includes the first light-emitting element  105 R, the second light-emitting element  105 G, and the third light-emitting element  105 B. The first light-emitting element  105 R includes the first electrode  101 , an EL layer  103 , and the second electrode  102 . A color filter  104 R is provided in a region overlapping with the first electrode  101 , the EL layer  103 , and the second electrode  102 . The second light-emitting element  105 G includes the first electrode  101 , the EL layer  103 , and the second electrode  102 . A color filter  104 G is provided in a region overlapping with the first electrode  101 , the EL layer  103 , and the second electrode  102 . The third light-emitting element  105 B includes the first electrode  101 , the EL layer  103 , and the second electrode  102 . A color filter  104 B is provided in a region overlapping with the first electrode  101 , the EL layer  103 , and the second electrode  102 . Note that the light-emitting elements include the same EL layer  103 . 
     The second electrode  102  included in each of the light-emitting elements illustrated in  FIG. 1B  is preferably formed using a light-transmitting electrode material. Accordingly, red light  106 R of light emitted from the EL layer  103  can be extracted from the first light-emitting element  105 R to the outside through the color filter  104 R. Furthermore, green light  106 G of the light emitted from the EL layer  103  can be extracted from the second light-emitting element  105 G to the outside through the color filter  104 G. In addition, blue light  106 B of the light emitted from the EL layer  103  can be extracted from the third light-emitting element  105 B to the outside through the color filter  104 B. This means that the color filter  104 R has a function of transmitting red light, the color filter  104 G has a function of transmitting green light, and the color filter  104 B has a function of transmitting blue light. 
     Although not illustrated in  FIGS. 1A and 1B , each of the first light-emitting element  105 R, the second light-emitting element  105 G, and the third light-emitting element  105 B in the light-emitting device described in this embodiment may be electrically connected to a transistor that controls light emission. 
     The EL layers ( 103 ,  103 R,  103 G, and  103 B) illustrated in  FIGS. 1A and 1B  each include functional layers such as a light-emitting layer containing a light-emitting substance, a hole-injection layer, a hole-transport layer, an electron-transport layer, and an electron-injection layer. In the case of stacked EL layers, a charge generation layer is positioned between the EL layers. 
     The light-emitting layers included in the EL layers ( 103 ,  103 R,  103 G, and  103 B) illustrated in  FIGS. 1A and 1B  can contain one or more kinds of organic compounds in addition to the light-emitting substance. One light-emitting layer or the stacked light-emitting layers may contain light-emitting substances of different colors. In the case where the EL layer ( 103 ,  103 R,  103 G, or  103 B) illustrated in  FIG. 1A  or  FIG. 1B  is formed of stacked EL layers, a charge generation layer is provided between the EL layers as described above. In that case, the EL layers preferably emit light with different colors. 
     The first light-emitting element  105 R, the second light-emitting element  105 G, and the third light-emitting element  105 B illustrated in  FIG. 1B  share the EL layer  103 . In that case, light with different colors can be obtained from the light-emitting elements while the EL layer  103  emits white light. 
     In the case where light emitted from the EL layer  103  is white light obtained by mixing light with a plurality of wavelengths are mixed as illustrated in  FIG. 1B , it is preferable to employ a microcavity structure by using the first electrode  101  as a reflective electrode and the second electrode  102  as a transflective electrode to intensify light with a specific wavelength. Note that a microcavity structure may be employed also in the case where the EL layers are separately formed for each light-emitting element as illustrated in  FIG. 1A . 
     Since the first light-emitting element  105 R illustrated in  FIG. 1A  or  FIG. 1B  is a light-emitting element that emits red light, the thickness of the first electrode  101  is preferably adjusted so that an optical path length between the first electrode  101  and the second electrode  102  may be set to an optical path length that increases the emission intensity of red light. Furthermore, since the second light-emitting element  105 G is a light-emitting element that emits green light, the thickness of the first electrode  101  is preferably adjusted so that an optical path length between the first electrode  101  and the second electrode  102  may be set to an optical path length that increases the emission intensity of green light. In addition, since the third light-emitting element  105 B is a light-emitting element that emits blue light, the thickness of the first electrode  101  is preferably adjusted so that an optical path length between the first electrode  101  and the second electrode  102  may be set to an optical path length that increases the emission intensity of blue light. 
     In the case where light emitted from the EL layer  103  is white light as illustrated in  FIG. 1B , it is desirable that red light, green light, and blue light that constitute white light have independent emission spectra that do not overlap with each other to prevent a reduction in color purity. The emission spectrum of green light and the emission spectrum of red light are especially likely to overlap with each other because their peak wavelengths are close to each other. The light-emitting substances contained in the EL layers and stacked structures of the EL layers are important in preventing such overlap of the emission spectra. The number of steps can be smaller in the case of light-emitting devices including a common EL layer than in the case of light-emitting devices including separately formed EL layers; however, some difficulties are caused. Thus, one embodiment of the present invention can provide not only a light-emitting device having favorable chromaticity for each emission color, but also a light-emitting device in which overlap of different emission spectra is prevented and chromaticity for each emission color is favorable particularly when a common light-emitting layer that emits white light is included. 
     The light-emitting device described in this embodiment includes a plurality of light-emitting elements and can display a full-color image. At present, some standards are established as quality indicators for full-color displays. 
     For example, the sRGB standard, which is an international standard for color spaces defined by the International Electrotechnical Commission (IEC) to standardize color reproduction on devices such as displays, printers, digital cameras, and scanners, is widely used. Note that in the sRGB standard, the chromaticities (x, y) on the CIE1931 chromaticity coordinates (x,y chromaticity coordinates) defined by the International Commission on Illumination (CIE) are (0.640, 0.330) for red (R), (0.300, 0.600) for green (G), and (0.150, 0.060) for blue (B). 
     In the NTSC standard, which is a color gamut standard for analog television systems defined by the National Television System Committee (NTSC) in America, the chromaticities (x, y) are (0.670, 0.330) for red (R), (0.210, 0.710) for green (G), and (0.140, 0.080) for blue (B). 
     In the DCI-P3 standard (defined by Digital Cinema Initiatives, LLC), which is the international unified standard used when distributing digital movies (cinema), the chromaticities (x, y) are (0.680, 0.320) for red (R), (0.265, 0.690) for green (G), and (0.150, 0.060) for blue (B). 
     In the BT.2020 standard for ultra high definition television (UHDTV, also referred to as Super Hi-Vision), which is defined by Japan Broadcasting Corporation (NHK), the chromaticities (x, y) are (0.708, 0.292) for red, (0.170, 0.797) for green, and (0.131, 0.046) for blue. 
     As described above, a variety of standards for displays are defined. The light-emitting device of one embodiment of the present invention includes light-emitting elements (a light-emitting element that emits red light, a light-emitting element that emits green light, and a light-emitting element that emits blue light) that cover chromaticity ranges (a region A, a region B, and a region C) represented by color coordinates in  FIG. 1C . Specifically, the light-emitting device includes at least the first light-emitting element  105 R from which the red light  106 R can be obtained, the second light-emitting element  105 G from which the green light  106 G can be obtained, and the third light-emitting element  105 B from which the blue light  106 B can be obtained. Light obtained from the first light-emitting element  105 R has chromaticity that falls within the region A in the color coordinates in  FIG. 1C , or has a chromaticity x of greater than 0.680 and less than or equal to 0.720 and a chromaticity y of greater than or equal to 0.260 and less than or equal to 0.320 on the CIE1931 chromaticity coordinates. Light obtained from the second light-emitting element  105 G has chromaticity that falls within the region B in the color coordinates in  FIG. 1C , or has a chromaticity x of greater than or equal to 0.130 and less than or equal to 0.250 and a chromaticity y of greater than 0.710 and less than or equal to 0.810. Light obtained from the third light-emitting element  105 B has chromaticity that falls within the region C in the color coordinates in  FIG. 1C , or has a chromaticity x of greater than or equal to 0.120 and less than or equal to 0.170 and a chromaticity y of greater than or equal to 0.020 and less than 0.060. Note that as illustrated in  FIG. 1B , a structure in which the light-emitting elements ( 105 R,  105 G, and  105 B) and the color filters ( 104 R,  104 G, and  104 B) are used in combination and light emissions obtained from the light-emitting elements ( 105 R,  105 G, and  105 B) through the color filters ( 104 R,  104 G, and  104 B) cover the above chromaticity ranges may be employed. A light-emitting device including such light-emitting elements can provide high-quality full-color displays. It is needless to say that a structure that covers the above chromaticity ranges without using color filters may be employed as illustrated in  FIG. 1A . 
     Note that the peak wavelength of the emission spectrum of the first light-emitting element  105 R illustrated in  FIG. 1A  is preferably greater than or equal to 620 nm and less than or equal to 680 nm. The peak wavelength of the emission spectrum of the second light-emitting element  105 G illustrated in  FIG. 1A  is preferably greater than or equal to 500 nm and less than or equal to 530 nm. The peak wavelength of the emission spectrum of the third light-emitting element  105 B illustrated in  FIG. 1A  is preferably greater than or equal to 430 nm and less than or equal to 460 nm. The half widths of the emission spectra of the light-emitting elements  105 R,  105 G, and  105 B are preferably greater than or equal to 5 nm and less than or equal to 45 nm, greater than or equal to 5 nm and less than or equal to 35 nm, and greater than or equal to 5 nm and less than or equal to 25 nm, respectively. The peak wavelengths and the half widths of emission spectra of light passed through the color filters illustrated in  FIG. 1B  have similar values. 
     In one embodiment of the present invention, the above chromaticities are preferably obtained so that the area ratio to the BT.2020 color gamut in the CIE chromaticity coordinates (x, y) can become higher than or equal to 80%, further preferably higher than or equal to 90%, or the color gamut coverage can become higher than or equal to 75%, further preferably higher than or equal to 85%. 
     The chromaticities may be measured with any of a luminance colorimeter, a spectroradiometer, and an emission spectrometer, and it is sufficient that the above-described chromaticities be met in any one of the measurements. Note that it is preferable that the above-described chromaticities be met in all of the measurements. 
     Note that the structures described in this embodiment can be combined with any of the structures described in the other embodiments as appropriate. 
     Embodiment 2 
     In this embodiment, light-emitting elements of one embodiment of the present invention will be described. 
     &lt;&lt;Basic Structure of Light-Emitting Element&gt;&gt; 
     A basic structure of a light-emitting element will be described.  FIG. 2A  illustrates a light-emitting element including, between a pair of electrodes, an EL layer having a light-emitting layer. Specifically, an EL layer  203  is provided between a first electrode  201  and a second electrode  202  (single structure). 
       FIG. 2B  illustrates a light-emitting element that has a stacked-layer structure (tandem structure) in which a plurality of EL layers (two EL layers  203   a  and  203   b  in  FIG. 2B ) are provided between a pair of electrodes and a charge generation layer  204  is provided between the EL layers. With the use of such a tandem light-emitting element, a light-emitting device which can be driven at low voltage with low power consumption can be obtained. 
     The charge generation layer  204  has a function of injecting electrons into one of the EL layers ( 203   a  or  203   b ) and injecting holes into the other of the EL layers ( 203   b  or  203   a ) when voltage is applied between the first electrode  201  and the second electrode  202 . Thus, when voltage is applied to the first electrode  201  in  FIG. 2B  such that the potential of the first electrode  201  becomes higher than that of the second electrode  202 , the charge generation layer  204  injects electrons into the EL layer  203   a  and injects holes into the EL layer  203   b.    
     Note that in terms of light extraction efficiency, the charge generation layer  204  preferably has a property of transmitting visible light (specifically, a visible light transmittance of 40% or higher). Furthermore, the charge generation layer  204  functions even if it has lower conductivity than the first electrode  201  or the second electrode  202 . 
       FIG. 2C  illustrates a stacked-layer structure of the EL layer  203  in the light-emitting element of one embodiment of the present invention. In this case, the first electrode  201  is regarded as functioning as an anode. The EL layer  203  has a structure in which a hole-injection layer  211 , a hole-transport layer  212 , a light-emitting layer  213 , an electron-transport layer  214 , and an electron-injection layer  215  are stacked in this order over the first electrode  201 . Even in the case where a plurality of EL layers are provided as in the tandem structure illustrated in  FIG. 2B , the layers in each EL layer are sequentially stacked from the anode side as described above. When the first electrode  201  is a cathode and the second electrode  202  is an anode, the stacking order of the layers is reversed. 
     The light-emitting layer  213  included in the EL layers ( 203 ,  203   a , and  203   b ) contains light-emitting substances and a plurality of substances in appropriate combination, so that fluorescence or phosphorescence of desired emission colors can be obtained. The light-emitting layer  213  may have a stacked-layer structure having different emission colors. In that case, light-emitting substances and other substances are different between the stacked light-emitting layers. Alternatively, the plurality of EL layers ( 203   a  and  203   b ) in  FIG. 2B  may exhibit their respective emission colors. Also in that case, light-emitting substances and other substances are different between the light-emitting layers. 
     In the light-emitting element of one embodiment of the present invention, for example, a micro optical resonator (microcavity) structure in which the first electrode  201  is a reflective electrode and the second electrode  202  is a transflective electrode can be employed in  FIG. 2C , whereby light emission from the light-emitting layer  213  in the EL layer  203  can be resonated between the electrodes and light emission transmitted from the second electrode  202  can be intensified. 
     Note that when the first electrode  201  of the light-emitting element is a reflective electrode having a structure in which a reflective conductive material and a light-transmitting conductive material (transparent conductive film) are stacked, optical adjustment can be performed by controlling the thickness of the transparent conductive film. Specifically, when the wavelength of light from the light-emitting layer  213  is λ, the distance between the first electrode  201  and the second electrode  202  is preferably adjusted to around mλ/2 (m is a natural number). 
     To amplify desired light (wavelength: λ) obtained from the light-emitting layer  213 , the optical path length from the first electrode  201  to a region where desired light is obtained in the light-emitting layer  213  (light-emitting region) and the optical path length from the second electrode  202  to the region where desired light is obtained in the light-emitting layer  213  (light-emitting region) are preferably adjusted to around (2m′+1)λ/4 (m′ is a natural number). Here, the light-emitting region means a region where holes and electrons are recombined in the light-emitting layer  213 . 
     By such optical adjustment, the spectrum of specific monochromatic light from the light-emitting layer  213  can be narrowed and light emission with high color purity can be obtained. 
     In that case, the optical path length between the first electrode  201  and the second electrode  202  is, to be exact, the total thickness from a reflective region in the first electrode  201  to a reflective region in the second electrode  202 . However, it is difficult to exactly determine the reflective regions in the first electrode  201  and the second electrode  202 ; thus, it is assumed that the above effect can be sufficiently obtained wherever the reflective regions may be set in the first electrode  201  and the second electrode  202 . Furthermore, the optical path length between the first electrode  201  and the light-emitting layer emitting desired light is, to be exact, the optical path length between the reflective region in the first electrode  201  and the light-emitting region where desired light is obtained in the light-emitting layer. However, it is difficult to precisely determine the reflective region in the first electrode  201  and the light-emitting region where desired light is obtained in the light-emitting layer; thus, it is assumed that the above effect can be sufficiently obtained wherever the reflective region and the light-emitting region may be set in the first electrode  201  and the light-emitting layer emitting desired light. 
     The light-emitting element in  FIG. 2C  has a microcavity structure, so that light rays (monochromatic light rays) with different wavelengths can be extracted even if the same EL layer is used. Thus, separate coloring for obtaining a plurality of emission colors (e.g., R, G, and B) is not necessary. Therefore, high resolution can be easily achieved. Note that a combination with coloring layers (color filters) is also possible. Furthermore, emission intensity of light with a specific wavelength in the front direction can be increased, whereby power consumption can be reduced. 
     In the light-emitting element of one embodiment of the present invention, at least one of the first electrode  201  and the second electrode  202  is a light-transmitting electrode (e.g., a transparent electrode or a transflective electrode). In the case where the light-transmitting electrode is a transparent electrode, the transparent electrode has a visible light transmittance of higher than or equal to 40%. In the case where the light-transmitting electrode is a transflective electrode, the transflective electrode has a visible light reflectance of higher than or equal to 20% and lower than or equal to 80%, and preferably higher than or equal to 40% and lower than or equal to 70%. These electrodes preferably have a resistivity of 1×10 −2  Ωcm or less. 
     Furthermore, when one of the first electrode  201  and the second electrode  202  is a reflective electrode in the light-emitting element of one embodiment of the present invention, the visible light reflectance of the reflective electrode is higher than or equal to 40% and lower than or equal to 100%, and preferably higher than or equal to 70% and lower than or equal to 100%. This electrode preferably has a resistivity of 1×10 −2  Ωcm or less. 
     &lt;&lt;Specific Structure and Fabrication Method of Light-Emitting Element&gt;&gt; 
     Specific structures and specific fabrication methods of light-emitting elements of embodiments of the present invention will be described with reference to  FIGS. 2A to 2D . Here, a light-emitting element having the tandem structure in  FIG. 2B  and a microcavity structure will be described with reference to  FIG. 2D . In the light-emitting element in  FIG. 2D  having a microcavity structure, the first electrode  201  is formed as a reflective electrode and the second electrode  202  is formed as a transflective electrode. Thus, a single-layer structure or a stacked-layer structure can be formed using one or more kinds of desired electrode materials. Note that the second electrode  202  is formed after formation of the EL layer  203   b , with the use of a material selected as described above. For fabrication of these electrodes, a sputtering method or a vacuum evaporation method can be used. 
     &lt;First Electrode and Second Electrode&gt; 
     As materials used for the first electrode  201  and the second electrode  202 , any of the materials below can be used in an appropriate combination as long as the functions of the electrodes described above can be fulfilled. For example, a metal, an alloy, an electrically conductive compound, a mixture of these, and the like can be appropriately used. Specifically, an In—Sn oxide (also referred to as ITO), an In—Si—Sn oxide (also referred to as ITSO), an In—Zn oxide, an In—W—Zn oxide, or the like can be used. In addition, it is possible to use a metal such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), or neodymium (Nd) or an alloy containing an appropriate combination of any of these metals. It is also possible to use a Group 1 element or a Group 2 element in the periodic table, which is not described above (e.g., lithium (Li), cesium (Cs), calcium (Ca), or strontium (Sr)), a rare earth metal such as europium (Eu) or ytterbium (Yb), an alloy containing an appropriate combination of any of these elements, graphene, or the like. 
     In the light-emitting element in  FIG. 2D , when the first electrode  201  is an anode, a hole-injection layer  211   a  and a hole-transport layer  212   a  of the EL layer  203   a  are sequentially stacked over the first electrode  201  by a vacuum evaporation method. After the EL layer  203   a  and the charge generation layer  204  are formed, a hole-injection layer  211   b  and a hole-transport layer  212   b  of the EL layer  203   b  are sequentially stacked over the charge generation layer  204  in a similar manner. 
     &lt;Hole-Injection Layer and Hole-Transport Layer&gt; 
     The hole-injection layers ( 211 ,  211   a , and  211   b ) inject holes from the first electrode  201  that is an anode or the charge generation layer ( 204 ) to the EL layers ( 203 ,  203   a , and  203   b ) and each contain a material with a high hole-injection property. 
     As examples of the material with a high hole-injection property, transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can be given. Alternatively, it is possible to use any of the following materials: phthalocyanine-based compounds such as phthalocyanine (abbreviation: H 2 Pc) and copper phthalocyanine (abbreviation: CuPc); aromatic amine compounds such as 4,4′-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB) and N,N-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N-diphenyl-(1,1′-biphenyl)-4,4′-diamine (abbreviation: DNTPD); high molecular compounds such as poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonic acid) (abbreviation: PEDOT/PSS); and the like. 
     Alternatively, as the material with a high hole-injection property, a composite material containing a hole-transport material and an acceptor material (an electron-accepting material) can also be used. In that case, the acceptor material extracts electrons from a hole-transport material, so that holes are generated in the hole-injection layers ( 211 ,  211   a , and  211   b ) and the holes are injected into the light-emitting layers ( 213 ,  213   a , and  213   b ) through the hole-transport layers ( 212 ,  212   a , and  212   b ). Note that each of the hole-injection layers ( 211 ,  211   a , and  211   b ) may be formed to have a single-layer structure using a composite material containing a hole-transport material and an acceptor material (electron-accepting material), or a stacked-layer structure in which a layer including a hole-transport material and a layer including an acceptor material (electron-accepting material) are stacked. 
     The hole-transport layers ( 212 ,  212   a , and  212   b ) transport the holes, which are injected from the first electrode  201  by the hole-injection layers ( 211 ,  211   a , and  211   b ), to the light-emitting layers ( 213 ,  213   a , and  213   b ). Note that the hole-transport layers ( 212 ,  212   a , and  212   b ) each contain a hole-transport material. It is particularly preferable that the HOMO level of the hole-transport material included in the hole-transport layers ( 212 ,  212   a , and  212   b ) be the same as or close to that of the hole-injection layers ( 211 ,  211   a , and  211   b ). 
     Examples of the acceptor material used for the hole-injection layers ( 211 ,  211   a , and  211   b ) include an oxide of a metal belonging to any of Group 4 to Group 8 of the periodic table. Specifically, molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide can be given. Among these, molybdenum oxide is especially preferable since it is stable in the air, has a low hygroscopic property, and is easy to handle. Alternatively, organic acceptors such as a quinodimethane derivative, a chloranil derivative, and a hexaazatriphenylene derivative can be used. Specifically, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F 4 -TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), or the like can be used. 
     The hole-transport materials used for the hole-injection layers ( 211 ,  211   a , and  211   b ) and the hole-transport layers ( 212 ,  212   a , and  212   b ) are preferably substances with a hole mobility of greater than or equal to 10 −6  cm 2 /Vs. Note that other substances may be used as long as the substances have a hole-transport property higher than an electron-transport property. 
     Preferred hole-transport materials are π-electron rich heteroaromatic compounds (e.g., carbazole derivatives and indole derivatives) and aromatic amine compounds, examples of which include compounds having an aromatic amine skeleton, such as 4,4′-bis[N-(1-naphthyl)-N-phenyl amino]biphenyl (abbreviation: NPB or α-NPD), N′,N′-bis(3-methylphenyl)-N,N-diphenyl-[1,1′-biphenyl]-4,4′-diamine (abbreviation: TPD), 4,4′-bis[N-(spiro-9,9′-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4′-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3′-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 3-[4-(9-phenanthryl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazol-3-amine (abbreviation: PCBiF), N-(1,1′-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 4,4′-diphenyl-4″-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4′-di(1-naphthyl)-4″-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9′-bifluoren-2-amine (abbreviation: PCBASF), 4,4′,4″-tris(carbazol-9-yl)triphenylamine (abbreviation: TCTA), 4,4′,4″-tris(N,N-diphenylamino)triphenylamine (abbreviation: 1DATA), and 4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA); compounds having a carbazole skeleton, such as 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4′-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 3,3′-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), and 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA); compounds having a thiophene skeleton, such as 4,4′,4″-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV); and compounds having a furan skeleton, such as 4,4′,4″-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). 
     A high molecular compound such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N′-[4-(4-diphenylamino)phenyl]phenyl-N′-phenylamino}phenyl)methacrylamide](abbreviation: PTPDMA), or poly[N,N-bis(4-butylphenyl)-N,N-bis(phenyl)benzidine](abbreviation: Poly-TPD) can also be used. 
     Note that the hole-transport material is not limited to the above examples and may be one of or a combination of various known materials when used for the hole-injection layers ( 211 ,  211   a , and  211   b ) and the hole-transport layers ( 212 ,  212   a , and  212   b ). Note that the hole-transport layers ( 212 ,  212   a , and  212   b ) may each be formed of a plurality of layers. That is, for example, the hole-transport layers may each have a stacked-layer structure of a first hole-transport layer and a second hole-transport layer. 
     In the light-emitting element in  FIG. 2D , the light-emitting layer  213   a  is formed over the hole-transport layer  212   a  of the EL layer  203   a  by a vacuum evaporation method. After the EL layer  203   a  and the charge generation layer  204  are formed, the light-emitting layer  213   b  is formed over the hole-transport layer  212   b  of the EL layer  203   b  by a vacuum evaporation method. 
     &lt;Light-Emitting Layer&gt; 
     The light-emitting layers ( 213 ,  213   a , and  213   b ) each contain a light-emitting substance. Note that as the light-emitting substance, a substance whose emission color is blue, violet, bluish violet, green, yellowish green, yellow, orange, red, or the like is appropriately used. When the plurality of light-emitting layers ( 213   a  and  213   b ) are formed using different light-emitting substances, different emission colors can be exhibited (for example, complementary emission colors are combined to achieve white light emission). Furthermore, a stacked-layer structure in which one light-emitting layer contains two or more kinds of light-emitting substances may be employed. 
     The light-emitting layers ( 213 ,  213   a , and  213   b ) may each contain one or more kinds of organic compounds (a host material and an assist material) in addition to a light-emitting substance (guest material). As the one or more kinds of organic compounds, one or both of the hole-transport material and the electron-transport material described in this embodiment can be used. 
     In the light-emitting element of one embodiment of the present invention, it is preferable that a light-emitting substance which emits blue light (a blue-light-emitting substance) be used as a guest material in one of the light-emitting layers ( 213   a  and  213   b ) and a material which emits green light (a green-light-emitting substance) and a material which emits red light (a red-light-emitting substance) be used in the other light-emitting layer. This manner is effective in the case where the blue-light-emitting substance (the blue-light-emitting layer) has lower light luminous efficiency or a shorter lifetime than the materials (layers) which emit other colors. Here, it is preferable that a light-emitting substance that converts singlet excitation energy into light emission in the visible light range be used as the blue-light-emitting substance and light-emitting substances that convert triplet excitation energy into light emission in the visible light range be used as the green- and red-light-emitting substances, whereby the spectrum balance between R, G, and B is improved. 
     There is no particular limitation on the light-emitting substances that can be used for the light-emitting layers ( 213 ,  213   a , and  213   b ), and a light-emitting substance that converts singlet excitation energy into light emission in the visible light range or a light-emitting substance that converts triplet excitation energy into light emission in the visible light range can be used. Examples of the light-emitting substance are given below. 
     As an example of the light-emitting substance that converts singlet excitation energy into light emission, a substance that emits fluorescence (fluorescent material) can be given. Examples of the substance that emits fluorescence include a pyrene derivative, an anthracene derivative, a triphenylene derivative, a fluorene derivative, a carbazole derivative, a dibenzothiophene derivative, a dibenzofuran derivative, a dibenzoquinoxaline derivative, a quinoxaline derivative, a pyridine derivative, a pyrimidine derivative, a phenanthrene derivative, and a naphthalene derivative. A pyrene derivative is particularly preferable because it has a high emission quantum yield. Specific examples of the pyrene derivative include N,N′-bis(3-methylphenyl)-N,N-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N′-diphenyl-N,N′-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N-bis(dibenzofuran-2-yl)-N,N-diphenylpyrene-1,6-diamine (abbreviation: 1,6FrAPrn), N,N′-bis(dibenzothiophen-2-yl)-N,N′-diphenylpyrene-1,6-diamine (abbreviation: 1,6ThAPrn), N,N′-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-6-amine](abbreviation: 1,6BnfAPrn), N,N′-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-02), and N,N′-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03). 
     In addition, it is possible to use 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2′-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4′-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2′-bipyridine (abbreviation: PAPP2BPy), N,N′-bis[4-(9H-carbazol-9-yl)phenyl]-N,N′-diphenylstilbene-4,4′-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4′-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4′-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), 4-(10-phenyl-9-anthryl)-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), 4-[4-(10-phenyl-9-anthryl)phenyl]-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPBA), perylene, 2,5,8,11-tetra(tert-butyl)perylene (abbreviation: TBP), N,N′-(2-tert-butylanthracene-9,10-diyldi-4,1-phenyl ene)bis[N,N′,N′-triphenyl-1,4-phenylenediamine](abbreviation: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N′,N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), or the like. 
     As examples of a light-emitting substance that converts triplet excitation energy into light emission, a substance that emits phosphorescence (phosphorescent material) and a thermally activated delayed fluorescence (TADF) material that exhibits thermally activated delayed fluorescence can be given. 
     Examples of a phosphorescent material include an organometallic complex, a metal complex (platinum complex), and a rare earth metal complex. These substances exhibit the respective emission colors (emission peaks) and thus, any of them is appropriately selected according to need. 
     As examples of a phosphorescent material which emits blue or green light and whose emission spectrum has a peak wavelength at greater than or equal to 450 nm and less than or equal to 570 nm, the following substances can be given. 
     For example, organometallic complexes having a 4H-triazole skeleton, such as tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp) 3 ]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz) 3 ]), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPrptz-3b) 3 ]), and tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPr5btz) 3 ]); organometallic complexes having a 1H-triazole skeleton, such as tris[3-methyl-1-(2-methylphenyl)-5-phenyl-H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp) 3 ]) and tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me) 3 ]); organometallic complexes having an imidazole skeleton, such as fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpmi) 3 ]) and tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-J]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me) 3 ]); organometallic complexes in which a phenylpyridine derivative having an electron-withdrawing group is a ligand, such as bis[2-(4′,6′-difluorophenyl)pyridinato-N,C 2′ ]iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4′,6′-difluorophenyl)pyridinato-N,C 2′ ]iridium(III) picolinate (abbreviation: FIrpic), bis {2-[3′,5′-bis(trifluoromethyl)phenyl]pyridinato-N,C 2′ }iridium(III) picolinate (abbreviation: [Ir(CF 3 ppy) 2 (pic)]), and bis[2-(4′,6′-difluorophenyl)pyridinato-N,C 2′ ]iridium(III) acetylacetonate (abbreviation: FIr(acac)); and the like can be given. 
     As examples of a phosphorescent material which emits green or yellow light and whose emission spectrum has a peak wavelength at greater than or equal to 495 nm and less than or equal to 590 nm, the following substances can be given. 
     For example, organometallic iridium complexes having a pyrimidine skeleton, such as tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) 3 ]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) 3 ]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) 2 (acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) 2 (acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm) 2 (acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm) 2 (acac)]), (acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl-κC}iridium(III) (abbreviation: [Ir(dmppm-dmp) 2 (acac)]), and (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm) 2 (acac)]); organometallic iridium complexes having a pyrazine skeleton, such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me) 2 (acac)]) and (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr) 2 (acac)]); organometallic iridium complexes having a pyridine skeleton, such as tris(2-phenylpyridinato-N,C 2′ )iridium(III) (abbreviation: [Ir(ppy) 3 ]), bis(2-phenylpyridinato-N,C 2′ )iridium(III) acetylacetonate (abbreviation: [Ir(ppy) 2 (acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq) 2 (acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq) 3 ]), tris(2-phenylquinolinato-N,C 2′ )iridium(III) (abbreviation: [Ir(pq) 3 ]), and bis(2-phenylquinolinato-N,C 2 )iridium(III) acetylacetonate (abbreviation: [Ir(pq) 2 (acac)]); organometallic complexes such as bis(2,4-diphenyl-1,3-oxazolato-N,C 2′ )iridium(III) acetylacetonate (abbreviation: [Ir(dpo) 2 (acac)]), bis{2-[4′-(perfluorophenyl)phenyl]pyridinato-N,C 2′ }iridium(III) acetylacetonate (abbreviation: [Ir(p-PF-ph) 2 (acac)]), and bis(2-phenylbenzothiazolato-N,C 2′ )iridium(III) acetylacetonate (abbreviation: [Ir(bt) 2 (acac)]); and rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac) 3 (Phen)]) can be given. 
     Among the above, an organometallic complex having a pyridine skeleton (particularly, a phenylpyridine skeleton) or a pyrimidine skeleton is a group of compounds effective for meeting the chromaticity of green in one embodiment of the present invention. 
     As examples of a phosphorescent material which emits yellow or red light and whose emission spectrum has a peak wavelength at greater than or equal to 570 nm and less than or equal to 750 nm, the following substances can be given. 
     For example, organometallic complexes having a pyrimidine skeleton, such as (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm) 2 (dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm) 2 (dpm)]), and (dipivaloylmethanato)bis[4,6-di(naphthalen-1-yl)pyrimidinato]iridium(III) (abbreviation: [Ir(d1npm) 2 (dpm)]); organometallic complexes having a pyrazine skeleton, such as (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr) 2 (acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr) 2 (dpm)]), bis {4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyrazinyl-N]phenyl-κC}(2,6-dimethyl-3,5-heptanedionato-κ 2 O,O′)iridium(III) (abbreviation: [Ir(dmdppr-P) 2 (dibm)]), bis {4,6-dimethyl-2-[5-(4-cyano-2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ 2 O,O′)iridium(III) (abbreviation: [Ir(dmdppr-dmCP) 2 (dpm)]), (acetylacetonato)bis[2-methyl-3-phenylquinoxalinato-N,C 2′ ]iridium(III) (abbreviation: [Ir(mpq) 2 (acac)]), (acetylacetonato)bis(2,3-diphenylquinoxalinato-N,C 2′ )iridium(III) (abbreviation: [Ir(dpq) 2 (acac)]), and (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq) 2 (acac)]); organometallic complexes having a pyridine skeleton, such as tris(1-phenylisoquinolinato-N,C 2′ )iridium(III) (abbreviation: [Ir(piq) 3 ]) and bis(1-phenylisoquinolinato-N,C 2′ )iridium(III) acetylacetonate (abbreviation: [Ir(piq) 2 (acac)]); platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrinplatinum(II) (abbreviation: [PtOEP]); and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM) 3 (Phen)]) and tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA) 3 (Phen)]) can be given. 
     Among the above, an organometallic iridium complex having a pyrazine skeleton is a group of compounds effective for meeting the chromaticity of red in one embodiment of the present invention. In particular, an organometallic iridium complex containing a cyano group (e.g., [Ir(dmdppr-dmCP) 2 (dpm)]) is preferable because it is stable. 
     Note that as the blue-light-emitting substance, a material whose photoluminescence peak wavelength is greater than or equal to 430 nm and less than or equal to 470 nm, preferably greater than or equal to 430 nm and less than or equal to 460 nm may be used. As the green-light-emitting substance, a material whose photoluminescence peak wavelength is greater than or equal to 500 nm and less than or equal to 540 nm, preferably greater than or equal to 500 nm and less than or equal to 530 nm may be used. As the red-light-emitting substance, a material whose photoluminescence peak wavelength is greater than or equal to 610 nm and less than or equal to 680 nm, preferably greater than or equal to 620 nm and less than or equal to 680 nm may be used. Note that the photoluminescence may be measured with either a solution or a thin film. 
     With the parallel use of such compounds and microcavity effect, the above chromaticity can be more easily met. Here, a transflective electrode (a metal thin film portion) that is needed for obtaining microcavity effect preferably has a thickness greater than or equal to 20 nm and less than or equal to 40 nm, and further preferably greater than 25 nm and less than or equal to 40 nm. However, the thickness greater than 40 nm possibly reduces the efficiency. 
     As the organic compounds (the host material and the assist material) used in the light-emitting layers ( 213 ,  213   a , and  213   b ), one or more kinds of substances having a larger energy gap than the light-emitting substance (the guest material) are used. Note that any of the hole-transport materials listed above and the electron-transport materials given below may be used as the organic compounds (the host material and the assist material). 
     When the light-emitting substance is a fluorescent material, it is preferable to use, as the host material, an organic compound that has a high energy level in a singlet excited state and has a low energy level in a triplet excited state. For example, an anthracene derivative or a tetracene derivative is preferably used. Specific examples include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4′-yl}anthracene (abbreviation: FLPPA), 5,12-diphenyltetracene, and 5,12-bis(biphenyl-2-yl)tetracene. 
     In the case where the light-emitting substance is a phosphorescent material, an organic compound having triplet excitation energy (energy difference between a ground state and a triplet excited state) which is higher than that of the light-emitting substance is preferably selected as the host material. In that case, it is possible to use a zinc- or aluminum-based metal complex, an oxadiazole derivative, a triazole derivative, a benzimidazole derivative, a quinoxaline derivative, a dibenzoquinoxaline derivative, a dibenzothiophene derivative, a dibenzofuran derivative, a pyrimidine derivative, a triazine derivative, a pyridine derivative, a bipyridine derivative, a phenanthroline derivative, an aromatic amine, a carbazole derivative, and the like. 
     Specific examples include metal complexes such as tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq 3 ), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq 2 ), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ); heterocyclic compounds such as 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2′,2″-(1,3,5-benzenetriyl)-tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), bathophenanthroline (abbreviation: BPhen), bathocuproine (abbreviation: BCP), 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), and 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11); and aromatic amine compounds such as NPB, TPD, and BSPB. 
     In addition, condensed polycyclic aromatic compounds such as anthracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, and dibenzo[g,p]chrysene derivatives can be used. Specifically, 9,10-diphenylanthracene (abbreviation: DPAnth), N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: CzA1PA), 4-(10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), YGAPA, PCAPA, N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazol-3-amine (abbreviation: PCAPBA), 9,10-diphenyl-2-[N-phenyl-N-(9-phenyl-9H-carbazol-3-yl)amino]anthracene (abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenylchrysene, N,N,N′,N′,N″,N″,N″,N′″-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: DPCzPA), 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9,9′-bianthryl (abbreviation: BANT), 9,9′-(stilbene-3,3′-diyl)diphenanthrene (abbreviation: DPNS), 9,9′-(stilbene-4,4′-diyl)diphenanthrene (abbreviation: DPNS2), 1,3,5-tri(1-pyrenyl)benzene (abbreviation: TPB3), or the like can be used. 
     In the case where a plurality of organic compounds are used for the light-emitting layers ( 213 ,  213   a , and  213   b ), it is preferable to use compounds that form an exciplex in combination with a light-emitting substance. In that case, although any of various organic compounds can be combined appropriately to be used, to form an exciplex efficiently, it is particularly preferable to combine a compound that easily accepts holes (hole-transport material) and a compound that easily accepts electrons (electron-transport material). As the hole-transport material and the electron-transport material, specifically, any of the materials described in this embodiment can be used. 
     The TADF material is a material that can up-convert a triplet excited state into a singlet excited state (i.e., reverse intersystem crossing is possible) using a little thermal energy and efficiently exhibits light emission (fluorescence) from the singlet excited state. The TADF is efficiently obtained under the condition where the difference in energy between the triplet excited level and the singlet excited level is greater than or equal to 0 eV and less than or equal to 0.2 eV, preferably greater than or equal to 0 eV and less than or equal to 0.1 eV. Note that “delayed fluorescence” exhibited by the TADF material refers to light emission having the same spectrum as normal fluorescence and an extremely long lifetime. The lifetime is 10 −6  seconds or longer, preferably 10 −3  seconds or longer. 
     Examples of the TADF material include fullerene, a derivative thereof, an acridine derivative such as proflavine, and eosin. Other examples include a metal-containing porphyrin, such as a porphyrin containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd). Examples of the metal-containing porphyrin include a protoporphyrin-tin fluoride complex (SnF 2 (Proto IX)), a mesoporphyrin-tin fluoride complex (SnF 2 (Meso IX)), a hematoporphyrin-tin fluoride complex (SnF 2 (Hemato IX)), a coproporphyrin tetramethyl ester-tin fluoride complex (SnF 2 (Copro III-4Me)), an octaethylporphyrin-tin fluoride complex (SnF 2 (OEP)), an etioporphyrin-tin fluoride complex (SnF 2 (Etio I)), and an octaethylporphyrin-platinum chloride complex (PtCl 2 OEP). 
     Alternatively, a heterocyclic compound having a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, such as 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (DMAC-DPS), or 10-phenyl-10H,10′H-spiro[acridin-9,9′-anthracen]-10′-one (ACRSA) can be used. Note that a substance in which the π-electron rich heteroaromatic ring is directly bonded to the π-electron deficient heteroaromatic ring is particularly preferable because both the donor property of the π-electron rich heteroaromatic ring and the acceptor property of the π-electron deficient heteroaromatic ring are increased and the energy difference between the singlet excited state and the triplet excited state becomes small. 
     Note that when a TADF material is used, the TADF material can be combined with another organic compound. 
     In the light-emitting element in  FIG. 2D , the electron-transport layer  214   a  is formed over the light-emitting layer  213   a  of the EL layer  203   a  by a vacuum evaporation method. After the EL layer  203   a  and the charge generation layer  204  are formed, the electron-transport layer  214   b  is formed over the light-emitting layer  213   b  of the EL layer  203   b  by a vacuum evaporation method. 
     &lt;Electron-Transport Layer&gt; 
     The electron-transport layers ( 214 ,  214   a , and  214   b ) transport the electrons, which are injected from the second electrode  202  by the electron-injection layers ( 215 ,  215   a , and  215   b ), to the light-emitting layers ( 213 ,  213   a , and  213   b ). Note that the electron-transport layers ( 214 ,  214   a , and  214   b ) each contain an electron-transport material. It is preferable that the electron-transport materials included in the electron-transport layers ( 214 ,  214   a , and  214   b ) be substances with an electron mobility of higher than or equal to 1×10 −6  cm 2 /Vs. Note that other substances may also be used as long as the substances have an electron-transport property higher than a hole-transport property. 
     Examples of the electron-transport material include metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, and a thiazole ligand; an oxadiazole derivative; a triazole derivative; a phenanthroline derivative; a pyridine derivative; and a bipyridine derivative. In addition, a π-electron deficient heteroaromatic compound such as a nitrogen-containing heteroaromatic compound can also be used. 
     Specifically, it is possible to use metal complexes such as Alq 3 , tris(4-methyl-8-quinolinolato)aluminum (abbreviation: Almq 3 ), bis(10-hydroxybenzo[h]quinolinato)beryllium (abbreviation: BeBq 2 ), BAlq, Zn(BOX) 2 , and bis[2-(2-hydroxyphenyl)benzothiazolato]zinc (abbreviation: Zn(BTZ) 2 ), heteroaromatic compounds such as 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 3-(4′-tert-butylphenyl)-4-phenyl-5-(4″-biphenyl)-1,2,4-triazole (abbreviation: TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole (abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), and 4,4′-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), and quinoxaline derivatives and dibenzoquinoxaline derivatives such as 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3′-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II). 
     Alternatively, a high molecular compound such as poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), or poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2′-bipyridine-6,6′-diyl)] (abbreviation: PF-BPy) can be used. 
     Each of the electron-transport layers ( 214 ,  214   a , and  214   b ) is not limited to a single layer, but may be a stack of two or more layers each containing any of the above substances. 
     In the light-emitting element in  FIG. 2D , the electron-injection layer  215   a  is formed over the electron-transport layer  214   a  of the EL layer  203   a  by a vacuum evaporation method. Subsequently, the EL layer  203   a  and the charge generation layer  204  are formed, the components up to the electron-transport layer  214   b  of the EL layer  203   b  are formed and then, the electron-injection layer  215   b  is formed thereover by a vacuum evaporation method. 
     &lt;Electron-Injection Layer&gt; 
     The electron-injection layers ( 215 ,  215   a , and  215   b ) each contain a substance having a high electron-injection property. The electron-injection layers ( 215 ,  215   a , and  215   b ) can each be formed using an alkali metal, an alkaline earth metal, or a compound thereof, such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF 2 ), or lithium oxide (LiO x ). A rare earth metal compound like erbium fluoride (ErF 3 ) can also be used. Electride may also be used for the electron-injection layers ( 215 ,  215   a , and  215   b ). Examples of the electride include a substance in which electrons are added at high concentration to calcium oxide-aluminum oxide. Any of the substances for forming the electron-transport layers ( 214 ,  214   a , and  214   b ), which are given above, can also be used. 
     A composite material in which an organic compound and an electron donor (donor) are mixed may also be used for the electron-injection layers ( 215 ,  215   a , and  215   b ). Such a composite material is excellent in an electron-injection property and an electron-transport property because electrons are generated in the organic compound by the electron donor. The organic compound here is preferably a material excellent in transporting the generated electrons; specifically, for example, the electron-transport materials for forming the electron-transport layers ( 214 ,  214   a , and  214   b ) (e.g., a metal complex or a heteroaromatic compound) can be used. As the electron donor, a substance showing an electron-donating property with respect to the organic compound may be used. Preferable examples are an alkali metal, an alkaline earth metal, and a rare earth metal. Specifically, lithium, cesium, magnesium, calcium, erbium, ytterbium, and the like can be given. Furthermore, an alkali metal oxide and an alkaline earth metal oxide are preferable, and a lithium oxide, a calcium oxide, a barium oxide, and the like can be given. Alternatively, a Lewis base such as magnesium oxide can be used. Further alternatively, an organic compound such as tetrathiafulvalene (abbreviation: TTF) can be used. 
     In the case where light obtained from the light-emitting layer  213   b  is amplified in the light-emitting element illustrated in  FIG. 2D , for example, the optical path length between the second electrode  202  and the light-emitting layer  213   b  is preferably less than one fourth of the wavelength k of light emitted from the light-emitting layer  213   b . In that case, the optical path length can be adjusted by changing the thickness of the electron-transport layer  214   b  or the electron-injection layer  215   b.    
     &lt;Charge Generation Layer&gt; 
     In the light-emitting element illustrated in  FIG. 2D , the charge generation layer  204  has a function of injecting electrons into the EL layer  203   a  and injecting holes into the EL layer  203   b  when a voltage is applied between the first electrode (anode)  201  and the second electrode (cathode)  202 . The charge generation layer  204  may have either a structure in which an electron acceptor (acceptor) is added to a hole-transport material or a structure in which an electron donor (donor) is added to an electron-transport material. Alternatively, both of these structures may be stacked. Note that forming the charge generation layer  204  by using any of the above materials can suppress an increase in drive voltage caused by the stack of the EL layers. 
     In the case where the charge generation layer  204  has a structure in which an electron acceptor is added to a hole-transport material, any of the materials described in this embodiment can be used as the hole-transport material. As the electron acceptor, it is possible to use 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F 4 -TCNQ), chloranil, and the like. In addition, an oxide of metals that belong to Group 4 to Group 8 of the periodic table can be given. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, rhenium oxide, or the like is used. 
     In the case where the charge generation layer  204  has a structure in which an electron donor is added to an electron-transport material, any of the materials described in this embodiment can be used as the electron-transport material. As the electron donor, it is possible to use an alkali metal, an alkaline earth metal, a rare earth metal, metals that belong to Groups 2 and 13 of the periodic table, or an oxide or carbonate thereof. Specifically, lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide, cesium carbonate, or the like is preferably used. Alternatively, an organic compound such as tetrathianaphthacene may be used as the electron donor. 
     &lt;Substrate&gt; 
     The light-emitting element described in this embodiment can be formed over any of a variety of substrates. Note that the type of the substrate is not limited to a certain type. Examples of the substrate include a semiconductor substrate (e.g., a single crystal substrate or a silicon substrate), an SOI substrate, a glass substrate, a quartz substrate, a plastic substrate, a metal substrate, a stainless steel substrate, a substrate including stainless steel foil, a tungsten substrate, a substrate including tungsten foil, a flexible substrate, an attachment film, paper including a fibrous material, and a base material film. 
     Examples of the glass substrate include a barium borosilicate glass substrate, an aluminoborosilicate glass substrate, and a soda lime glass substrate. Examples of a flexible substrate, an attachment film, and a base material film include plastics typified by polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyether sulfone (PES); a synthetic resin such as acrylic; polypropylene; polyester; polyvinyl fluoride; polyvinyl chloride; polyamide; polyimide; aramid; epoxy; an inorganic vapor deposition film; and paper. 
     For fabrication of the light-emitting element in this embodiment, a vacuum process such as an evaporation method or a solution process such as a spin coating method or an ink-jet method can be used. When an evaporation method is used, a physical vapor deposition method (PVD method) such as a sputtering method, an ion plating method, an ion beam evaporation method, a molecular beam evaporation method, or a vacuum evaporation method, a chemical vapor deposition method (CVD method), or the like can be used. Specifically, the functional layers (the hole-injection layers ( 211   a  and  211   b ), the hole-transport layers ( 212   a  and  212   b ), the light-emitting layers ( 213   a  and  213   b ), the electron-transport layers ( 214   a  and  214   b ), the electron-injection layers ( 215   a  and  215   b )) included in the EL layers and the charge generation layer  204  of the light-emitting element can be formed by an evaporation method (e.g., a vacuum evaporation method), a coating method (e.g., a dip coating method, a die coating method, a bar coating method, a spin coating method, or a spray coating method), a printing method (e.g., an ink-jet method, screen printing (stencil), offset printing (planography), flexography (relief printing), gravure printing, micro-contact printing, or nanoimprint lithography), or the like. 
     Note that materials that can be used for the functional layers (the hole-injection layers ( 211   a  and  211   b ), the hole-transport layers ( 212   a  and  212   b ), the light-emitting layers ( 213   a  and  213   b ), the electron-transport layers ( 214   a  and  214   b ), and the electron-injection layers ( 215   a  and  215   b )) that are included in the EL layers ( 203   a  and  203   b ) and the charge generation layer  204  in the light-emitting element described in this embodiment are not limited to the above materials, and other materials can be used in combination as long as the functions of the layers are fulfilled. For example, a high molecular compound (e.g., an oligomer, a dendrimer, or a polymer), a middle molecular compound (a compound between a low molecular compound and a high molecular compound with a molecular weight of 400 to 4000), an inorganic compound (e.g., a quantum dot material), or the like can be used. The quantum dot may be a colloidal quantum dot, an alloyed quantum dot, a core-shell quantum dot, a core quantum dot, or the like. 
     The structures described in this embodiment can be combined with any of the structures described in the other embodiments as appropriate. 
     Embodiment 3 
     In this embodiment, the light-emitting device of one embodiment of the present invention will be described with reference to  FIG. 3A . Note that a light-emitting device illustrated in  FIG. 3A  is an active matrix light-emitting device in which transistors (FETs)  302  are electrically connected to light-emitting elements ( 303 R,  303 G,  303 B, and  303 W) over a first substrate  301 . The plurality of light-emitting elements ( 303 R,  303 G,  303 B, and  303 W) include a common EL layer  304  and each have a microcavity structure in which the optical path length between electrodes is adjusted depending on the emission color of the light-emitting element. The light-emitting device is a top-emission light-emitting device in which light is emitted from the EL layer  304  through color filters ( 306 R,  306 G, and  306 B) formed on a second substrate  305 . 
     The light-emitting device illustrated in  FIG. 3A  is fabricated such that a first electrode  307  functions as a reflective electrode and a second electrode  308  functions as a transflective electrode. Note that description in any of the other embodiments can be referred to as appropriate for electrode materials for the first electrode  307  and the second electrode  308 . 
     In the case where the light-emitting element  303 R functions as a red light-emitting element, the light-emitting element  303 G functions as a green light-emitting element, the light-emitting element  303 B functions as a blue light-emitting element, and the light-emitting element  303 W functions as a white light-emitting element in  FIG. 3A , for example, a gap between the first electrode  307  and the second electrode  308  in the light-emitting element  303 R is adjusted to have an optical path length  300 R, a gap between the first electrode  307  and the second electrode  308  in the light-emitting element  303 G is adjusted to have an optical path length  300 G, and a gap between the first electrode  307  and the second electrode  308  in the light-emitting element  303 B is adjusted to have an optical path length  300 B as illustrated in  FIG. 3B . Note that optical adjustment can be performed in such a manner that a conductive layer  307 R is stacked over the first electrode  307  in the light-emitting element  303 R and a conductive layer  307 G is stacked over the first electrode  307  in the light-emitting element  303 G as illustrated in  FIG. 3B . 
     The second substrate  305  is provided with the color filters ( 306 R,  306 G, and  306 B). Note that the color filters each transmit visible light in a specific wavelength range and blocks visible light in a specific wavelength range. Thus, as illustrated in  FIG. 3A , the color filter  306 R that transmits only light in the red wavelength range is provided in a position overlapping with the light-emitting element  303 R, whereby red light emission can be obtained from the light-emitting element  303 R. Furthermore, the color filter  306 G that transmits only light in the green wavelength range is provided in a position overlapping with the light-emitting element  303 G, whereby green light emission can be obtained from the light-emitting element  303 G. Moreover, the color filter  306 B that transmits only light in the blue wavelength range is provided in a position overlapping with the light-emitting element  303 B, whereby blue light emission can be obtained from the light-emitting element  303 B. Note that the light-emitting element  303 W can emit white light without a color filter. Note that a black layer (black matrix)  309  may be provided at an end portion of each color filter. The color filters ( 306 R,  306 G, and  306 B) and the black layer  309  may be covered with an overcoat layer formed using a transparent material. 
     Although the light-emitting device in  FIG. 3A  has a structure in which light is extracted from the second substrate  305  side (top emission structure), a structure in which light is extracted from the first substrate  301  side where the FETs  302  are formed (bottom emission structure) may be employed. Note that in the light-emitting device having a top emission structure, the first substrate  301  can be a light-blocking substrate or a light-transmitting substrate, whereas in a light-emitting device having a bottom emission structure, the first substrate  301  needs to be a light-transmitting substrate. 
     In  FIG. 3A , the light-emitting elements are the red light-emitting element, the green light-emitting element, the blue light-emitting element, and the white light-emitting element; however, the light-emitting elements of one embodiment of the present invention are not limited to the above, and a yellow light-emitting element or an orange light-emitting element may be used. Note that description in any of the other embodiments can be referred to as appropriate for materials that are used for the EL layers (a light-emitting layer, a hole-injection layer, a hole-transport layer, an electron-transport layer, an electron-injection layer, a charge generation layer, and the like) to fabricate each of the light-emitting elements. In that case, a color filter needs to be appropriately selected depending on the emission color of the light-emitting element. 
     With the above structure, a light-emitting device including light-emitting elements that exhibit a plurality of emission colors can be fabricated. 
     Note that the structures described in this embodiment can be combined with any of the structures described in the other embodiments as appropriate. 
     Embodiment 4 
     In this embodiment, a light-emitting device that is one embodiment of the present invention will be described. 
     The use of the element structure of the light-emitting element of one embodiment of the present invention allows fabrication of an active matrix light-emitting device or a passive matrix light-emitting device. Note that an active matrix light-emitting device has a structure including a combination of a light-emitting element and a transistor (FET). Thus, each of a passive matrix light-emitting device and an active matrix light-emitting device is one embodiment of the present invention. Note that any of the light-emitting elements described in other embodiments can be used in the light-emitting device described in this embodiment. 
     In this embodiment, an active matrix light-emitting device will be described with reference to  FIGS. 4A and 4B . 
       FIG. 4A  is a top view illustrating the light-emitting device and  FIG. 4B  is a cross-sectional view taken along chain line A-A′ in  FIG. 4A . The active matrix light-emitting device includes a pixel portion  402 , a driver circuit portion (source line driver circuit)  403 , and driver circuit portions (gate line driver circuits) ( 404   a  and  404   b ) that are provided over a first substrate  401 . The pixel portion  402  and the driver circuit portions ( 403 ,  404   a , and  404   b ) are sealed between the first substrate  401  and a second substrate  406  with a sealant  405 . 
     A lead wiring  407  is provided over the first substrate  401 . The lead wiring  407  is connected to an FPC  408  that is an external input terminal. Note that the FPC  408  transmits a signal (e.g., a video signal, a clock signal, a start signal, or a reset signal) or a potential from the outside to the driver circuit portions ( 403 ,  404   a , and  404   b ). The FPC  408  may be provided with a printed wiring board (PWB). Note that the light-emitting device provided with an FPC or a PWB is included in the category of a light-emitting device. 
       FIG. 4B  illustrates a cross-sectional structure of the light-emitting device. 
     The pixel portion  402  includes a plurality of pixels each of which includes an FET (switching FET)  411 , an FET (current control FET)  412 , and a first electrode  413  electrically connected to the FET  412 . Note that the number of FETs included in each pixel is not particularly limited and can be set appropriately. 
     As FETs  409 ,  410 ,  411 , and  412 , for example, a staggered transistor or an inverted staggered transistor can be used without particular limitation. A top-gate transistor, a bottom-gate transistor, or the like may be used. 
     Note that there is no particular limitation on the crystallinity of a semiconductor that can be used for the FETs  409 ,  410 ,  411 , and  412 , and an amorphous semiconductor or a semiconductor having crystallinity (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor partly including crystal regions) may be used. A semiconductor having crystallinity is preferably used, in which case deterioration of the transistor characteristics can be suppressed. 
     For the semiconductor, a Group 14 element, a compound semiconductor, an oxide semiconductor, an organic semiconductor, or the like can be used, for example. As a typical example, a semiconductor containing silicon, a semiconductor containing gallium arsenide, or an oxide semiconductor containing indium can be used. 
     The driver circuit portion  403  includes the FET  409  and the FET  410 . The FET  409  and the FET  410  may be formed with a circuit including transistors having the same conductivity type (either n-channel transistors or p-channel transistors) or a CMOS circuit including an n-channel transistor and a p-channel transistor. Furthermore, a driver circuit may be provided outside. 
     An end portion of the first electrode  413  is covered with an insulator  414 . The insulator  414  can be formed using an organic compound such as a negative photosensitive resin or a positive photosensitive resin (acrylic resin), or an inorganic compound such as silicon oxide, silicon oxynitride, or silicon nitride. The insulator  414  preferably has a curved surface with curvature at an upper end portion or a lower end portion thereof. In that case, favorable coverage with a film formed over the insulator  414  can be obtained. 
     An EL layer  415  and a second electrode  416  are stacked over the first electrode  413 . The EL layer  415  includes a light-emitting layer, a hole-injection layer, a hole-transport layer, an electron-transport layer, an electron-injection layer, a charge generation layer, and the like. 
     The structure and materials described in any of the other embodiments can be used for the components of a light-emitting element  417  described in this embodiment. Although not illustrated, the second electrode  416  is electrically connected to the FPC  408  that is an external input terminal. 
     Although the cross-sectional view in  FIG. 4B  illustrates only one light-emitting element  417 , a plurality of light-emitting elements are arranged in a matrix in the pixel portion  402 . Light-emitting elements that emit light of three kinds of colors (R, G, and B) are selectively formed in the pixel portion  402 , whereby a light-emitting device capable of displaying a full-color image can be obtained. In addition to the light-emitting elements that emit light of three kinds of colors (R, G, and B), for example, light-emitting elements that emit light of white (W), yellow (Y), magenta (M), cyan (C), and the like may be formed. For example, the light-emitting elements that emit light of some of the above colors are used in combination with the light-emitting elements that emit light of three kinds of colors (R, G, and B), whereby effects such as an improvement in color purity and a reduction in power consumption can be achieved. Alternatively, a light-emitting device which is capable of displaying a full-color image may be fabricated by a combination with color filters. 
     When the second substrate  406  and the first substrate  401  are bonded to each other with the sealant  405 , the FETs ( 409 ,  410 ,  411 , and  412 ) and the light-emitting element  417  over the first substrate  401  are provided in a space  418  surrounded by the first substrate  401 , the second substrate  406 , and the sealant  405 . Note that the space  418  may be filled with an inert gas (e.g., nitrogen or argon) or an organic substance (including the sealant  405 ). 
     An epoxy-based resin, glass frit, or the like can be used for the sealant  405 . It is preferable to use a material that is permeable to as little moisture and oxygen as possible for the sealant  405 . As the second substrate  406 , a substrate that can be used as the first substrate  401  can be similarly used. Thus, any of the various substrates described in the other embodiments can be appropriately used. As the substrate, a glass substrate, a quartz substrate, or a plastic substrate made of fiber reinforced plastic (FRP), polyvinyl fluoride (PVF), polyester, acrylic, or the like can be used. In the case where glass frit is used for the sealant, the first substrate  401  and the second substrate  406  are preferably glass substrates in terms of adhesion. 
     Accordingly, the active matrix light-emitting device can be obtained. 
     In the case where the active matrix light-emitting device is provided over a flexible substrate, the FETs and the light-emitting element may be directly formed over the flexible substrate; alternatively, the FETs and the light-emitting element may be formed over a substrate provided with a separation layer and then separated at the separation layer by application of heat, force, laser, or the like to be transferred to a flexible substrate. For the separation layer, a stack including inorganic films such as a tungsten film and a silicon oxide film, or an organic resin film of polyimide or the like can be used, for example. Examples of the flexible substrate include, in addition to a substrate over which a transistor can be formed, a paper substrate, a cellophane substrate, an aramid film substrate, a polyimide film substrate, a cloth substrate (including a natural fiber (e.g., silk, cotton, or hemp), a synthetic fiber (e.g., nylon, polyurethane, or polyester), a regenerated fiber (e.g., acetate, cupra, rayon, or regenerated polyester), or the like), a leather substrate, and a rubber substrate. With the use of any of these substrates, an increase in durability, an increase in heat resistance, a reduction in weight, and a reduction in thickness can be achieved. 
     Note that the structures described in this embodiment can be combined with any of the structures described in the other embodiments as appropriate. 
     Embodiment 5 
     In this embodiment, examples of a variety of electronic devices and an automobile manufactured using a light-emitting device of one embodiment of the present invention will be described. 
     Examples of the electronic device including the light-emitting device are television devices (also referred to as TV or television receivers), monitors for computers and the like, cameras such as digital cameras and digital video cameras, digital photo frames, cellular phones (also referred to as mobile phones or portable telephone devices), portable game machines, portable information terminals, audio playback devices, large game machines such as pachinko machines, and the like. Specific examples of the electronic devices are illustrated in  FIGS. 5A, 5B, 5C, 5D, 5D ′- 1 , and  5 D′- 2  and  FIGS. 6A to 6C . 
       FIG. 5A  illustrates an example of a television device. In a television device  7100 , a display portion  7103  is incorporated in a housing  7101 . The display portion  7103  can display images and may be a touch panel (input/output device) including a touch sensor (input device). Note that the light-emitting device of one embodiment of the present invention can be used for the display portion  7103 . In addition, here, the housing  7101  is supported by a stand  7105 . 
     The television device  7100  can be operated with an operation switch of the housing  7101  or a separate remote controller  7110 . With operation keys  7109  of the remote controller  7110 , channels and volume can be controlled and images displayed on the display portion  7103  can be controlled. Furthermore, the remote controller  7110  may be provided with a display portion  7107  for displaying data output from the remote controller  7110 . 
     Note that the television device  7100  is provided with a receiver, a modem, and the like. With the use of the receiver, general television broadcasts can be received. Moreover, when the television device is connected to a communication network with or without wires via the modem, one-way (from a sender to a receiver) or two-way (between a sender and a receiver or between receivers) information communication can be performed. 
       FIG. 5B  illustrates a computer, which includes a main body  7201 , a housing  7202 , a display portion  7203 , a keyboard  7204 , an external connection port  7205 , a pointing device  7206 , and the like. Note that this computer can be manufactured using the light-emitting device of one embodiment of the present invention for the display portion  7203 . The display portion  7203  may be a touch panel (input/output device) including a touch sensor (input device). 
       FIG. 5C  illustrates a smart watch, which includes a housing  7302 , a display portion  7304 , operation buttons  7311  and  7312 , a connection terminal  7313 , a band  7321 , a clasp  7322 , and the like. 
     The display portion  7304  mounted in the housing  7302  serving as a bezel includes a non-rectangular display region. The display portion  7304  can display an icon  7305  indicating time, another icon  7306 , and the like. The display portion  7304  may be a touch panel (input/output device) including a touch sensor (input device). 
     The smart watch illustrated in  FIG. 5C  can have a variety of functions, such as a function of displaying a variety of information (e.g., a still image, a moving image, and a text image) on a display portion, a touch panel function, a function of displaying a calendar, date, time, and the like, a function of controlling processing with a variety of software (programs), a wireless communication function, a function of being connected to a variety of computer networks with a wireless communication function, a function of transmitting and receiving a variety of data with a wireless communication function, and a function of reading a program or data stored in a recording medium and displaying the program or data on a display portion. 
     The housing  7302  can include a speaker, a sensor (a sensor having a function of measuring force, displacement, position, speed, acceleration, angular velocity, rotational frequency, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, electric power, radiation, flow rate, humidity, gradient, oscillation, odor, or infrared rays), a microphone, and the like. Note that the smart watch can be manufactured using the light-emitting device for the display portion  7304 . 
       FIG. 5D  illustrates an example of a cellular phone (e.g., smartphone). A cellular phone  7400  includes a housing  7401  provided with a display portion  7402 , a microphone  7406 , a speaker  7405 , a camera  7407 , an external connection portion  7404 , an operation button  7403 , and the like. In the case where a light-emitting device is manufactured by forming the light-emitting element of one embodiment of the present invention over a flexible substrate, the light-emitting device can be used for the display portion  7402  having a curved surface as illustrated in  FIG. 5D . 
     When the display portion  7402  of the cellular phone  7400  illustrated in  FIG. 5D  is touched with a finger or the like, data can be input to the cellular phone  7400 . In addition, operations such as making a call and composing e-mail can be performed by touch on the display portion  7402  with a finger or the like. 
     There are mainly three screen modes of the display portion  7402 . The first mode is a display mode mainly for displaying an image. The second mode is an input mode mainly for inputting data such as characters. The third mode is a display-and-input mode in which two modes of the display mode and the input mode are combined. 
     For example, in the case of making a call or composing e-mail, a character input mode mainly for inputting characters is selected for the display portion  7402  so that characters displayed on the screen can be input. In this case, it is preferable to display a keyboard or number buttons on almost the entire screen of the display portion  7402 . 
     When a detection device such as a gyroscope sensor or an acceleration sensor is provided inside the cellular phone  7400 , display on the screen of the display portion  7402  can be automatically changed by determining the orientation of the cellular phone  7400  (whether the cellular phone is placed horizontally or vertically for a landscape mode or a portrait mode). 
     The screen modes are changed by touch on the display portion  7402  or operation with the operation button  7403  of the housing  7401 . The screen modes can be switched depending on the kind of images displayed on the display portion  7402 . For example, when a signal of an image displayed on the display portion is a signal of moving image data, the screen mode is switched to the display mode. When the signal is a signal of text data, the screen mode is switched to the input mode. 
     Moreover, in the input mode, if a signal detected by an optical sensor in the display portion  7402  is detected and the input by touch on the display portion  7402  is not performed for a certain period, the screen mode may be controlled so as to be changed from the input mode to the display mode. 
     The display portion  7402  may function as an image sensor. For example, an image of a palm print, a fingerprint, or the like is taken by touch on the display portion  7402  with the palm or the finger, whereby personal authentication can be performed. In addition, by providing a backlight or a sensing light source that emits near-infrared light in the display portion, an image of a finger vein, a palm vein, or the like can be taken. 
     The light-emitting device can be used for a cellular phone having a structure illustrated in  FIG. 5D ′- 1  or  FIG. 5D ′- 2 , which is another structure of the cellular phone (e.g., smartphone). 
     Note that in the case of the structure illustrated in  FIG. 5D ′- 1  or  FIG. 5D ′- 2 , text data, image data, or the like can be displayed on second screens  7502 ( 1 ) and  7502 ( 2 ) of housings  7500 ( 1 ) and  7500 ( 2 ) as well as first screens  7501 ( 1 ) and  7501 ( 2 ). Such a structure enables a user to easily see text data, image data, or the like displayed on the second screens  7502 ( 1 ) and  7502 ( 2 ) while the cellular phone is placed in the user&#39;s breast pocket. 
     Another electronic device including a light-emitting device is a foldable portable information terminal illustrated in  FIGS. 6A to 6C .  FIG. 6A  illustrates a portable information terminal  9310  which is opened.  FIG. 6B  illustrates the portable information terminal  9310  which is being opened or being folded.  FIG. 6C  illustrates the portable information terminal  9310  which is folded. The portable information terminal  9310  is highly portable when folded. The portable information terminal  9310  is highly browsable when opened because of a seamless large display region. 
     A display portion  9311  is supported by three housings  9315  joined together by hinges  9313 . Note that the display portion  9311  may be a touch panel (input/output device) including a touch sensor (input device). By bending the display portion  9311  at a connection portion between two housings  9315  with the use of the hinges  9313 , the portable information terminal  9310  can be reversibly changed in shape from an opened state to a folded state. The light-emitting device of one embodiment of the present invention can be used for the display portion  9311 . A display region  9312  in the display portion  9311  is a display region that is positioned at a side surface of the portable information terminal  9310  which is folded. On the display region  9312 , information icons, file shortcuts of frequently used applications or programs, and the like can be displayed, and confirmation of information and start of application and the like can be smoothly performed. 
       FIGS. 7A and 7B  illustrate an automobile including a light-emitting device. The light-emitting device can be incorporated in the automobile, and specifically, can be included in lights  5101  (including lights of the rear part of the car), a wheel cover  5102 , a part or the whole of a door  5103 , or the like on the outer side of the automobile which is illustrated in  FIG. 7A . The light-emitting device can also be included in a display portion  5104 , a steering wheel  5105 , a gear lever  5106 , a seat  5107 , an inner rearview mirror  5108 , or the like on the inner side of the automobile which is illustrated in  FIG. 7B , or in a part of a glass window. 
     As described above, the electronic devices and the automobile can be obtained using the light-emitting device of one embodiment of the present invention. Note that the light-emitting device can be used for electronic devices and automobiles in a variety of fields without being limited to those described in this embodiment. 
     Note that the structures described in this embodiment can be combined with any of the structures described in the other embodiments as appropriate. 
     Embodiment 6 
     In this embodiment, the structures of lighting devices fabricated using the light-emitting device of one embodiment of the present invention or a light-emitting element which is a part of the light-emitting device will be described with reference to  FIGS. 8A to 8D . 
       FIGS. 8A to 8D  are examples of cross-sectional views of lighting devices.  FIGS. 8A and 8B  illustrate bottom-emission lighting devices in which light is extracted from the substrate side, and  FIGS. 8C and 8D  illustrate top-emission lighting devices in which light is extracted from the sealing substrate side. 
     A lighting device  4000  illustrated in  FIG. 8A  includes a light-emitting element  4002  over a substrate  4001 . In addition, the lighting device  4000  includes a substrate  4003  with unevenness on the outside of the substrate  4001 . The light-emitting element  4002  includes a first electrode  4004 , an EL layer  4005 , and a second electrode  4006 . 
     The first electrode  4004  is electrically connected to an electrode  4007 , and the second electrode  4006  is electrically connected to an electrode  4008 . In addition, an auxiliary wiring  4009  electrically connected to the first electrode  4004  may be provided. Note that an insulating layer  4010  is formed over the auxiliary wiring  4009 . 
     The substrate  4001  and a sealing substrate  4011  are bonded to each other with a sealant  4012 . A desiccant  4013  is preferably provided between the sealing substrate  4011  and the light-emitting element  4002 . The substrate  4003  has the unevenness illustrated in  FIG. 8A , whereby the extraction efficiency of light emitted from the light-emitting element  4002  can be increased. 
     Instead of the substrate  4003 , a diffusion plate  4015  may be provided on the outside of the substrate  4001  as in a lighting device  4100  illustrated in  FIG. 8B . 
     A lighting device  4200  illustrated in  FIG. 8C  includes a light-emitting element  4202  over a substrate  4201 . The light-emitting element  4202  includes a first electrode  4204 , an EL layer  4205 , and a second electrode  4206 . 
     The first electrode  4204  is electrically connected to an electrode  4207 , and the second electrode  4206  is electrically connected to an electrode  4208 . An auxiliary wiring  4209  electrically connected to the second electrode  4206  may be provided. An insulating layer  4210  may be provided under the auxiliary wiring  4209 . 
     The substrate  4201  and a sealing substrate  4211  with unevenness are bonded to each other with a sealant  4212 . A barrier film  4213  and a planarization film  4214  may be provided between the sealing substrate  4211  and the light-emitting element  4202 . The sealing substrate  4211  has the unevenness illustrated in  FIG. 8C , whereby the extraction efficiency of light emitted from the light-emitting element  4202  can be increased. 
     Instead of the sealing substrate  4211 , a diffusion plate  4215  may be provided over the light-emitting element  4202  as in a lighting device  4300  illustrated in  FIG. 8D . 
     Note that with the use of the light-emitting device of one embodiment of the present invention or a light-emitting element which is a part of the light-emitting device as described in this embodiment, a lighting device having desired chromaticity can be provided. 
     Note that the structures described in this embodiment can be combined with any of the structures described in the other embodiments as appropriate. 
     Embodiment 7 
     In this embodiment, application examples of a lighting device fabricated using the light-emitting device of one embodiment of the present invention or a light-emitting element which is a part of the light-emitting device will be described with reference to  FIG. 9 . 
     A ceiling light  8001  can be used as an indoor lighting device. Examples of the ceiling light  8001  include a direct-mount light and an embedded light. Besides, application to a cord pendant light (light that is suspended from a ceiling by a cord) is also possible. 
     A foot light  8002  lights a floor so that safety on the floor can be improved. For example, it can be effectively used in a bedroom, on a staircase, or on a passage. In that case, the size or shape of the foot light can be changed depending on the area or structure of a room. 
     A sheet-like lighting  8003  is a thin sheet-like lighting device. The sheet-like lighting, which is attached to a wall when used, is space-saving and thus can be used for a wide variety of uses. Furthermore, the area of the sheet-like lighting can be increased. The sheet-like lighting can also be used on a wall or housing having a curved surface. 
     In addition, a lighting device  8004  in which the direction of light from a light source is controlled to be only a desired direction can be used. 
     Besides the above examples, when the light-emitting device of one embodiment of the present invention or a light-emitting element which is a part of the light-emitting device is used as part of furniture in a room, a lighting device that functions as the furniture can be obtained. 
     As described above, a variety of lighting devices that include the light-emitting device can be obtained. Note that these lighting devices are also embodiments of the present invention. 
     The structures described in this embodiment can be combined with any of the structures described in the other embodiments as appropriate. 
     Embodiment 8 
     In this embodiment, touch panels including the light-emitting device of one embodiment of the present invention will be described with reference to  FIGS. 10A and 10B ,  FIGS. 11A and 11B ,  FIGS. 12A and 12B ,  FIGS. 13A and 13B , and  FIG. 14 . 
       FIGS. 10A and 10B  are perspective views of a touch panel  2000 . Note that  FIGS. 10A and 10B  illustrate only main components of the touch panel  2000  for simplicity. 
     The touch panel  2000  includes a display panel  2501  and a touch sensor  2595  (see  FIG. 10B ). The touch panel  2000  includes a substrate  2510 , a substrate  2570 , and a substrate  2590 . 
     The display panel  2501  includes, over the substrate  2510 , a plurality of pixels and a plurality of wirings  2511  through which signals are supplied to the pixels. The plurality of wirings  2511  are led to a peripheral portion of the substrate  2510 , and parts of the plurality of wirings  2511  form a terminal  2519 . The terminal  2519  is electrically connected to an FPC  2509 ( 1 ). 
     The substrate  2590  includes the touch sensor  2595  and a plurality of wirings  2598  electrically connected to the touch sensor  2595 . The plurality of wirings  2598  are led to a peripheral portion of the substrate  2590 , and parts of the plurality of wirings  2598  form a terminal  2599 . The terminal  2599  is electrically connected to an FPC  2509 ( 2 ). Note that in  FIG. 10B , electrodes, wirings, and the like of the touch sensor  2595  provided on the back side of the substrate  2590  (the side facing the substrate  2570 ) are indicated by solid lines for clarity. 
     As the touch sensor  2595 , a capacitive touch sensor can be used, for example. Examples of the capacitive touch sensor include a surface capacitive touch sensor, a projected capacitive touch sensor, and the like. 
     Examples of the projected capacitive touch sensor are a self-capacitive touch sensor, a mutual capacitive touch sensor, and the like, which differ mainly in the driving method. The use of a mutual capacitive type is preferable because multiple points can be sensed simultaneously. 
     First, an example of using a projected capacitive touch sensor will be described below with reference to  FIG. 10B . Note that in the case of a projected capacitive touch sensor, a variety of sensors that can sense proximity or touch of a sensing target such as a finger can be used. 
     The projected capacitive touch sensor  2595  includes electrodes  2591  and electrodes  2592 . The electrodes  2591  are electrically connected to any of the plurality of wirings  2598 , and the electrodes  2592  are electrically connected to any of the other wirings  2598 . The electrodes  2592  each have a shape of a plurality of quadrangles arranged in one direction with one corner of a quadrangle connected to one corner of another quadrangle with a wiring  2594 , as illustrated in  FIGS. 10A and 10B . In the same manner, the electrodes  2591  each have a shape of a plurality of quadrangles arranged with one corner of a quadrangle connected to one corner of another quadrangle; however, the direction in which the electrodes  2591  are connected is a direction crossing the direction in which the electrodes  2592  are connected. Note that the direction in which the electrodes  2591  are connected and the direction in which the electrodes  2592  are connected are not necessarily perpendicular to each other, and the electrodes  2591  may be arranged to intersect with the electrodes  2592  at an angle greater than 0° and less than 90°. 
     The intersecting area of the electrode  2592  and the wiring  2594  is preferably as small as possible. Such a structure allows a reduction in the area of a region where the electrodes are not provided, reducing variation in transmittance. As a result, variation in luminance of light passing through the touch sensor  2595  can be reduced. 
     Note that the shapes of the electrodes  2591  and the electrodes  2592  are not limited thereto and can be any of a variety of shapes. For example, the plurality of electrodes  2591  may be provided so that a space between the electrodes  2591  is reduced as much as possible, and the plurality of electrodes  2592  may be provided with an insulating layer located between the electrodes  2591  and  2592 . In this case, it is preferable to provide, between two adjacent electrodes  2592 , a dummy electrode electrically insulated from these electrodes because the area of regions having different transmittances can be reduced. 
     Next, the touch panel  2000  will be described in detail with reference to  FIGS. 11A and 11B .  FIGS. 11A and 11B  correspond to cross-sectional views taken along dashed-dotted line X 1 -X 2  in  FIG. 10A . 
     The touch panel  2000  includes the touch sensor  2595  and the display panel  2501 . 
     The touch sensor  2595  includes the electrodes  2591  and the electrodes  2592  provided in a staggered arrangement in contact with the substrate  2590 , an insulating layer  2593  covering the electrodes  2591  and the electrodes  2592 , and the wiring  2594  that electrically connects the adjacent electrodes  2591  to each other. Between the adjacent electrodes  2591 , the electrode  2592  is provided. 
     The electrodes  2591  and the electrodes  2592  can be formed using a light-transmitting conductive material. As the light-transmitting conductive material, an In—Sn oxide (also referred to as ITO), an In—Si—Sn oxide (also referred to as ITSO), an In—Zn oxide, an In—W—Zn oxide, or the like can be used. In addition, it is possible to use a metal such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), or neodymium (Nd) or an alloy containing an appropriate combination of any of these metals. A graphene compound may be used as well. When a graphene compound is used, it can be formed, for example, by reducing a graphene oxide film. As a reducing method, a method with application of heat, a method with laser irradiation, or the like can be employed. 
     For example, the electrodes  2591  and  2592  can be formed by depositing a light-transmitting conductive material on the substrate  2590  by a sputtering method and then removing an unneeded portion by any of various patterning techniques such as photolithography. 
     Examples of a material for the insulating layer  2593  include a resin such as an acrylic resin or an epoxy resin, a resin having a siloxane bond, and an inorganic insulating material such as silicon oxide, silicon oxynitride, or aluminum oxide. 
     The adjacent electrodes  2591  are electrically connected to each other with the wiring  2594  formed in part of the insulating layer  2593 . Note that a material for the wiring  2594  preferably has higher conductivity than materials for the electrodes  2591  and  2592  to reduce electrical resistance. 
     The wiring  2598  is electrically connected to any of the electrodes  2591  and  2592 . Part of the wiring  2598  functions as a terminal. For the wiring  2598 , a metal material such as aluminum, gold, platinum, silver, nickel, titanium, tungsten, chromium, molybdenum, iron, cobalt, copper, or palladium or an alloy material containing any of these metal materials can be used. 
     Through the terminal  2599 , the wiring  2598  and the FPC  2509 ( 2 ) are electrically connected to each other. The terminal  2599  can be formed using any of various kinds of anisotropic conductive films (ACF), anisotropic conductive pastes (ACP), and the like. 
     An adhesive layer  2597  is provided in contact with the wiring  2594 . That is, the touch sensor  2595  is attached to the display panel  2501  so that they overlap with each other with the adhesive layer  2597  provided therebetween. Note that the substrate  2570  as illustrated in  FIG. 11A  may be provided over the surface of the display panel  2501  that is in contact with the adhesive layer  2597 ; however, the substrate  2570  is not always needed. 
     The adhesive layer  2597  has a light-transmitting property. For example, a thermosetting resin or an ultraviolet curable resin can be used; specifically, a resin such as an acrylic resin, a urethane-based resin, an epoxy-based resin, or a siloxane-based resin can be used. 
     The display panel  2501  in  FIG. 11A  includes, between the substrate  2510  and the substrate  2570 , a plurality of pixels arranged in a matrix and a driver circuit. Each pixel includes a light-emitting element and a pixel circuit that drives the light-emitting element. 
     In  FIG. 11A , a pixel  2502 R is shown as an example of the pixel of the display panel  2501 , and a scan line driver circuit  2503   g  is shown as an example of the driver circuit. 
     The pixel  2502 R includes a light-emitting element  2550 R and a transistor  2502   t  that can supply electric power to the light-emitting element  2550 R. 
     The transistor  2502   t  is covered with an insulating layer  2521 . The insulating layer  2521  has a function of providing a flat surface by covering unevenness caused by the transistor and the like that have been already formed. The insulating layer  2521  may serve also as a layer for preventing diffusion of impurities. That is preferable because a reduction in the reliability of the transistor or the like due to diffusion of impurities can be prevented. 
     The light-emitting element  2550 R is electrically connected to the transistor  2502   t  through a wiring. It is one electrode of the light-emitting element  2550 R that is directly connected to the wiring. An end portion of the one electrode of the light-emitting element  2550 R is covered with an insulator  2528 . 
     The light-emitting element  2550 R includes an EL layer between a pair of electrodes. A coloring layer  2567 R is provided to overlap with the light-emitting element  2550 R, and part of light emitted from the light-emitting element  2550 R is transmitted through the coloring layer  2567 R and extracted in the direction indicated by an arrow in the drawing. A light-blocking layer  2567 BM is provided at an end portion of the coloring layer, and a sealing layer  2560  is provided between the light-emitting element  2550 R and the coloring layer  2567 R. 
     Note that when the sealing layer  2560  is provided on the side from which light from the light-emitting element  2550 R is extracted, the sealing layer  2560  preferably has a light-transmitting property. The sealing layer  2560  preferably has a higher refractive index than the air. 
     The scan line driver circuit  2503   g  includes a transistor  2503   t  and a capacitor  2503   c . Note that the driver circuit and the pixel circuits can be formed in the same process over the same substrate. Thus, in a manner similar to that of the transistor  2502   t  in the pixel circuit, the transistor  2503   t  in the driver circuit (the scan line driver circuit  2503   g ) is also covered with the insulating layer  2521 . 
     The wirings  2511  through which a signal can be supplied to the transistor  2503   t  are provided. The terminal  2519  is provided in contact with the wiring  2511 . The terminal  2519  is electrically connected to the FPC  2509 ( 1 ), and the FPC  2509 ( 1 ) has a function of supplying signals such as an image signal and a synchronization signal. Note that a printed wiring board (PWB) may be attached to the FPC  2509 ( 1 ). 
     Although the case where the display panel  2501  illustrated in  FIG. 11A  includes a bottom-gate transistor is described, the structure of the transistor is not limited thereto, and any of transistors with various structures can be used. In each of the transistors  2502   t  and  2503   t  illustrated in  FIG. 11A , a semiconductor layer containing an oxide semiconductor can be used for a channel region. Alternatively, a semiconductor layer containing amorphous silicon or a semiconductor layer containing polycrystalline silicon that is obtained by crystallization process such as laser annealing can be used for a channel region. 
       FIG. 11B  illustrates the structure that includes a top-gate transistor instead of the bottom-gate transistor illustrated in  FIG. 11A . The kind of the semiconductor layer that can be used for the channel region does not depend on the structure of the transistor. 
     In the touch panel  2000  illustrated in  FIG. 11A , an anti-reflection layer  2567   p  overlapping with at least the pixel is preferably provided on a surface of the touch panel on the side from which light from the pixel is extracted, as illustrated in  FIG. 11A . As the anti-reflection layer  2567   p , a circular polarizing plate or the like can be used. 
     For the substrates  2510 ,  2570 , and  2590  in  FIG. 11A , for example, a flexible material having a vapor permeability of 1×10 −5  g/(m 2 ·day) or lower, preferably 1×10 −6  g/(m 2 ·day) or lower, can be favorably used. Alternatively, it is preferable to use the materials that make these substrates have substantially the same coefficient of thermal expansion. For example, the coefficients of linear expansion of the materials are 1×10 −3 /K or lower, preferably 5×10 −5 /K or lower, and further preferably 1×10 −5 /K or lower. 
     Next, a touch panel  2000 ′ having a structure different from that of the touch panel  2000  illustrated in  FIGS. 11A and 11B  will be described with reference to  FIGS. 12A and 12B . It can be used as a touch panel as well as the touch panel  2000 . 
       FIGS. 12A and 12B  are cross-sectional views of the touch panel  2000 ′. In the touch panel  2000 ′ illustrated in  FIGS. 12A and 12B , the position of the touch sensor  2595  relative to the display panel  2501  is different from that in the touch panel  2000  illustrated in  FIGS. 11A and 11B . Only different structures will be described below, and the above description of the touch panel  2000  can be referred to for the other similar structures. 
     The coloring layer  2567 R overlaps with the light-emitting element  2550 R. The light-emitting element  2550 R illustrated in  FIG. 12A  emits light to the side where the transistor  2502   t  is provided. That is, (part of) light emitted from the light-emitting element  2550 R passes through the coloring layer  2567 R and is extracted in the direction indicated by an arrow in  FIG. 12A . Note that the light-blocking layer  2567 BM is provided at an end portion of the coloring layer  2567 R. 
     The touch sensor  2595  is provided on the transistor  2502   t  side (the far side from the light-emitting element  2550 R) of the display panel  2501  (see  FIG. 12A ). 
     The adhesive layer  2597  is in contact with the substrate  2510  of the display panel  2501  and attaches the display panel  2501  and the touch sensor  2595  to each other in the structure illustrated in  FIG. 12A . The substrate  2510  is not necessarily provided between the display panel  2501  and the touch sensor  2595  that are attached to each other by the adhesive layer  2597 . 
     As in the touch panel  2000 , transistors with a variety of structures can be used for the display panel  2501  in the touch panel  2000 ′. Although a bottom-gate transistor is used in  FIG. 12A , a top-gate transistor may be used as illustrated in  FIG. 12B . 
     An example of a driving method of the touch panel will be described with reference to  FIGS. 13A and 13B . 
       FIG. 13A  is a block diagram illustrating the structure of a mutual capacitive touch sensor.  FIG. 13A  illustrates a pulse voltage output circuit  2601  and a current sensing circuit  2602 . Note that in  FIG. 13A , six wirings X 1  to X 6  represent electrodes  2621  to which a pulse voltage is applied, and six wirings Y 1  to Y 6  represent electrodes  2622  that detect changes in current.  FIG. 13A  also illustrates capacitors  2603  that are each formed in a region where the electrodes  2621  and  2622  overlap with each other. Note that functional replacement between the electrodes  2621  and  2622  is possible. 
     The pulse voltage output circuit  2601  is a circuit for sequentially applying a pulse voltage to the wirings X 1  to X 6 . By application of a pulse voltage to the wirings X 1  to X 6 , an electric field is generated between the electrodes  2621  and  2622  of the capacitor  2603 . When the electric field between the electrodes is shielded, for example, a change occurs in the capacitor  2603  (mutual capacitance). The approach or contact of a sensing target can be sensed by utilizing this change. 
     The current sensing circuit  2602  is a circuit for detecting changes in current flowing through the wirings Y 1  to Y 6  that are caused by the change in mutual capacitance in the capacitor  2603 . No change in current value is detected in the wirings Y 1  to Y 6  when there is no approach or contact of a sensing target, whereas a decrease in current value is detected when mutual capacitance is decreased owing to the approach or contact of a sensing target. Note that an integrator circuit or the like is used for sensing of current values. 
       FIG. 13B  is a timing chart showing input and output waveforms in the mutual capacitive touch sensor illustrated in  FIG. 13A . In  FIG. 13B , sensing of a sensing target is performed in all the rows and columns in one frame period.  FIG. 13B  shows a period when a sensing target is not sensed (not touched) and a period when a sensing target is sensed (touched). Sensed current values of the wirings Y 1  to Y 6  are shown as the waveforms of voltage values. 
     A pulse voltage is sequentially applied to the wirings X 1  to X 6 , and the waveforms of the wirings Y 1  to Y 6  change in response to the pulse voltage. When there is no approach or contact of a sensing target, the waveforms of the wirings Y 1  to Y 6  change uniformly in response to changes in the voltages of the wirings X 1  to X 6 . The current value is decreased at the point of approach or contact of a sensing target and accordingly the waveform of the voltage value changes. By detecting a change in mutual capacitance in this manner, the approach or contact of a sensing target can be sensed. 
     Although  FIG. 13A  illustrates a passive-type touch sensor in which only the capacitor  2603  is provided at the intersection of wirings as a touch sensor, an active-type touch sensor including a transistor and a capacitor may be used.  FIG. 14  illustrates an example of a sensor circuit included in an active-type touch sensor. 
     The sensor circuit in  FIG. 14  includes the capacitor  2603  and transistors  2611 ,  2612 , and  2613 . 
     A signal G 2  is input to a gate of the transistor  2613 . A voltage VRES is applied to one of a source and a drain of the transistor  2613 , and one electrode of the capacitor  2603  and a gate of the transistor  2611  are electrically connected to the other of the source and the drain of the transistor  2613 . One of a source and a drain of the transistor  2611  is electrically connected to one of a source and a drain of the transistor  2612 , and a voltage VSS is applied to the other of the source and the drain of the transistor  2611 . A signal G 1  is input to a gate of the transistor  2612 , and a wiring ML is electrically connected to the other of the source and the drain of the transistor  2612 . The voltage VSS is applied to the other electrode of the capacitor  2603 . 
     Next, the operation of the sensor circuit in  FIG. 14  will be described. First, a potential for turning on the transistor  2613  is supplied as the signal G 2 , and a potential with respect to the voltage VRES is thus applied to a node n connected to the gate of the transistor  2611 . Then, a potential for turning off the transistor  2613  is applied as the signal G 2 , whereby the potential of the node n is maintained. Then, mutual capacitance of the capacitor  2603  changes owing to the approach or contact of a sensing target such as a finger, and accordingly the potential of the node n is changed from VRES. 
     In reading operation, a potential for turning on the transistor  2612  is supplied as the signal G 1 . A current flowing through the transistor  2611 , that is, a current flowing through the wiring ML is changed depending on the potential of the node n. By sensing this current, the approach or contact of a sensing target can be sensed. 
     In each of the transistors  2611 ,  2612 , and  2613 , an oxide semiconductor layer is preferably used as a semiconductor layer in which a channel region is formed. In particular, it is preferable to use such a transistor as the transistor  2613  because the potential of the node n can be held for a long time and the frequency of operation of resupplying VRES to the node n (refresh operation) can be reduced. 
     Note that the structures described in this embodiment can be combined with any of the structures described in the other embodiments as appropriate. 
     Embodiment 9 
     In this embodiment, as a display device including the structure of the light-emitting device of one embodiment of the present invention, a display device that includes a reflective liquid crystal element and a light-emitting element and that can display an image both in a transmissive mode and a reflective mode will be described with reference to  FIGS. 15A ,  15 B 1 , and  15 B 2 ,  FIG. 16 , and  FIG. 17 . Such a display device can also be referred to as an emissive OLED and reflective LC hybrid display (ER-hybrid display). 
     The display device described in this embodiment can be driven with extremely low power consumption for displaying an image using the reflective mode in a bright place such as outdoors. Meanwhile, in a dark place such as indoors or in a night environment, an image with a wide color gamut and high color reproducibility can be displayed with the use of the transmissive mode. Thus, by combination of these modes, the display device can display an image with low power consumption and high color reproducibility as compared with the case of a conventional display panel. 
     As an example of the display device of this embodiment, description will be made of a display device in which a liquid crystal element provided with a reflective electrode and a light-emitting element are stacked and an opening in the reflective electrode is provided in a position overlapping with the light-emitting element. Visible light is reflected by the reflective electrode in the reflective mode and light emitted from the light-emitting element is emitted through the opening in the reflective electrode in the transmissive mode. Note that transistors used for driving these elements (the liquid crystal element and the light-emitting element) are preferably formed on the same plane. It is preferable that the liquid crystal element and the light-emitting element be stacked with an insulating layer therebetween. 
       FIG. 15A  is a block diagram illustrating a display device described in this embodiment. A display device  3000  includes a circuit (G)  3001 , a circuit (S)  3002 , and a display portion  3003 . In the display portion  3003 , a plurality of pixels  3004  are arranged in an R direction and a C direction in a matrix. A plurality of wirings G 1 , wirings G 2 , wirings ANO, and wirings CSCOM are electrically connected to the circuit (G)  3001 . These wirings are also electrically connected to the plurality of pixels  3004  arranged in the R direction. A plurality of wirings S 1  and wirings S 2  are electrically connected to the circuit (S)  3002 , and these wirings are also electrically connected to the plurality of pixels  3004  arranged in the C direction. 
     Each of the plurality of pixels  3004  includes a liquid crystal element and a light-emitting element. The liquid crystal element and the light-emitting element include portions overlapping with each other. 
     FIG.  15 B 1  shows the shape of a conductive film  3005  serving as a reflective electrode of the liquid crystal element included in the pixel  3004 . Note that an opening  3007  is provided in a position  3006  which is part of the conductive film  3005  and which overlaps with the light-emitting element. That is, light emitted from the light-emitting element is emitted through the opening  3007 . 
     The pixels  3004  in FIG.  15 B 1  are arranged such that the adjacent pixels  3004  in the R direction exhibit different colors. Furthermore, the openings  3007  are provided so as not to be arranged in a line in the R direction. Such arrangement has an effect of suppressing crosstalk between the light-emitting elements of adjacent pixels  3004 . Furthermore, there is an advantage that element formation is facilitated. 
     The opening  3007  can have a polygonal shape, a quadrangular shape, an elliptical shape, a circular shape, a cross shape, a stripe shape, or a slit-like shape, for example. 
     FIG.  15 B 2  illustrates another example of the arrangement of the conductive films  3005 . 
     The ratio of the opening  3007  to the total area of the conductive film  3005  (excluding the opening  3007 ) affects the display of the display device. That is, a problem is caused in that as the area of the opening  3007  is larger, the display using the liquid crystal element becomes darker; in contrast, as the area of the opening  3007  is smaller, the display using the light-emitting element becomes darker. Furthermore, in addition to the problem of the ratio of the opening, a small area of the opening  3007  itself also causes a problem in that extraction efficiency of light emitted from the light-emitting element is decreased. The ratio of the opening  3007  to the total area of the conductive film  3005  (excluding the opening  3007 ) is preferably 5% or more and 60% or less because the display quality can be maintained even when the liquid crystal element and the light-emitting element are used in a combination. 
     Next, an example of a circuit configuration of the pixel  3004  is described with reference to  FIG. 16 .  FIG. 16  illustrates two adjacent pixels  3004 . 
     The pixel  3004  includes a transistor SW 1 , a capacitor C 1 , a liquid crystal element  3010 , a transistor SW 2 , a transistor M, a capacitor C 2 , a light-emitting element  3011 , and the like. Note that these components are electrically connected to any of the wiring G 1 , the wiring G 2 , the wiring ANO, the wiring CSCOM, the wiring S 1 , and the wiring S 2  in the pixel  3004 . The liquid crystal element  3010  and the light-emitting element  3011  are electrically connected to a wiring VCOM 1  and a wiring VCOM 2 , respectively. 
     A gate of the transistor SW 1  is connected to the wiring G 1 . One of a source and a drain of the transistor SW 1  is connected to the wiring S 1 , and the other of the source and the drain is connected to one electrode of the capacitor C 1  and one electrode of the liquid crystal element  3010 . The other electrode of the capacitor C 1  is connected to the wiring CSCOM. The other electrode of the liquid crystal element  3010  is connected to the wiring VCOM 1 . 
     A gate of the transistor SW 2  is connected to the wiring G 2 . One of a source and a drain of the transistor SW 2  is connected to the wiring S 2 , and the other of the source and the drain is connected to one electrode of the capacitor C 2  and a gate of the transistor M. The other electrode of the capacitor C 2  is connected to one of a source and a drain of the transistor M and the wiring ANO. The other of the source and the drain of the transistor M is connected to one electrode of the light-emitting element  3011 . Furthermore, the other electrode of the light-emitting element  3011  is connected to the wiring VCOM 2 . 
     Note that the transistor M includes two gates between which a semiconductor is provided and which are electrically connected to each other. With such a structure, the amount of current flowing through the transistor M can be increased. 
     The on/off state of the transistor SW 1  is controlled by a signal from the wiring G 1 . A predetermined potential is applied from the wiring VCOM 1 . Furthermore, orientation of liquid crystals of the liquid crystal element  3010  can be controlled by a signal from the wiring S 1 . A predetermined potential is applied from the wiring CSCOM. 
     The on/off state of the transistor SW 2  is controlled by a signal from the wiring G 2 . By the difference between the potentials applied from the wiring VCOM 2  and the wiring ANO, the light-emitting element  3011  can emit light. Furthermore, the conduction state of the transistor M can be controlled by a signal from the wiring S 2 . 
     Accordingly, in the structure of this embodiment, in the case of the reflective mode, the liquid crystal element  3010  is controlled by the signals supplied from the wiring G 1  and the wiring S 1  and optical modulation is utilized, whereby an image can be displayed. In the case of the transmissive mode, the light-emitting element  3011  can emit light when the signals are supplied from the wiring G 2  and the wiring S 2 . In the case where both modes are performed at the same time, desired driving can be performed on the basis of the signals from the wiring G 1 , the wiring G 2 , the wiring S 1 , and the wiring S 2 . 
     Next, specific description will be given with reference to  FIG. 17 , a schematic cross-sectional view of the display device  3000  described in this embodiment. 
     The display device  3000  includes a light-emitting element  3023  and a liquid crystal element  3024  between substrates  3021  and  3022 . Note that the light-emitting element  3023  and the liquid crystal element  3024  are formed with an insulating layer  3025  positioned therebetween. That is, the light-emitting element  3023  is positioned between the substrate  3021  and the insulating layer  3025 , and the liquid crystal element  3024  is positioned between the substrate  3022  and the insulating layer  3025 . 
     A transistor  3015 , a transistor  3016 , a transistor  3017 , a coloring layer  3028 , and the like are provided between the insulating layer  3025  and the light-emitting element  3023 . 
     A bonding layer  3029  is provided between the substrate  3021  and the light-emitting element  3023 . The light-emitting element  3023  includes a conductive layer  3030  serving as one electrode, an EL layer  3031 , and a conductive layer  3032  serving as the other electrode which are stacked in this order over the insulating layer  3025 . In the light-emitting element  3023  that is a bottom emission light-emitting element, the conductive layer  3032  and the conductive layer  3030  contain a material that reflects visible light and a material that transmits visible light, respectively. Light emitted from the light-emitting element  3023  is transmitted through the coloring layer  3028  and the insulating layer  3025  and then transmitted through the liquid crystal element  3024  via an opening  3033 , thereby being emitted to the outside of the substrate  3022 . 
     In addition to the liquid crystal element  3024 , a coloring layer  3034 , a light-blocking layer  3035 , an insulating layer  3046 , a structure  3036 , and the like are provided between the insulating layer  3025  and the substrate  3022 . The liquid crystal element  3024  includes a conductive layer  3037  serving as one electrode, a liquid crystal  3038 , a conductive layer  3039  serving as the other electrode, alignment films  3040  and  3041 , and the like. Note that the liquid crystal element  3024  is a reflective liquid crystal element and the conductive layer  3039  serves as a reflective electrode; thus, the conductive layer  3039  is formed using a material with high reflectivity. Furthermore, the conductive layer  3037  serves as a transparent electrode, and thus is formed using a material that transmits visible light. The alignment films  3040  and  3041  are provided on the conductive layers  3037  and  3039  and in contact with the liquid crystal  3038 . The insulating layer  3046  is provided so as to cover the coloring layer  3034  and the light-blocking layer  3035  and serves as an overcoat. Note that the alignment films  3040  and  3041  are not necessarily provided. 
     The opening  3033  is provided in part of the conductive layer  3039 . A conductive layer  3043  is provided in contact with the conductive layer  3039 . Since the conductive layer  3043  has a light-transmitting property, a material transmitting visible light is used for the conductive layer  3043 . 
     The structure  3036  serves as a spacer that prevents the substrate  3022  from coming closer to the insulating layer  3025  than required. The structure  3036  is not necessarily provided. 
     One of a source and a drain of the transistor  3015  is electrically connected to the conductive layer  3030  in the light-emitting element  3023 . For example, the transistor  3015  corresponds to the transistor M in  FIG. 16 . 
     One of a source and a drain of the transistor  3016  is electrically connected to the conductive layer  3039  and the conductive layer  3043  in the liquid crystal element  3024  through a terminal portion  3018 . That is, the terminal portion  3018  has a function of electrically connecting the conductive layers provided on both surfaces of the insulating layer  3025 . The transistor  3016  corresponds to the transistor SW 1  in  FIG. 16 . 
     A terminal portion  3019  is provided in a region where the substrates  3021  and  3022  do not overlap with each other. Similarly to the terminal portion  3018 , the terminal portion  3019  electrically connects the conductive layers provided on both surfaces of the insulating layer  3025 . The terminal portion  3019  is electrically connected to a conductive layer obtained by processing the same conductive film as the conductive layer  3043 . Thus, the terminal portion  3019  and an FPC  3044  can be electrically connected to each other through a connection layer  3045 . 
     A connection portion  3047  is provided in part of a region where a bonding layer  3042  is provided. In the connection portion  3047 , the conductive layer obtained by processing the same conductive film as the conductive layer  3043  and part of the conductive layer  3037  are electrically connected with a connector  3048 . Accordingly, a signal or a potential input from the FPC  3044  can be supplied to the conductive layer  3037  through the connector  3048 . 
     The structure  3036  is provided between the conductive layer  3037  and the conductive layer  3043 . The structure  3036  has a function of maintaining a cell gap of the liquid crystal element  3024 . 
     As the conductive layer  3043 , a metal oxide, a metal nitride, or an oxide such as an oxide semiconductor whose resistance is reduced is preferably used. In the case of using an oxide semiconductor, a material in which at least one of the concentrations of hydrogen, boron, phosphorus, nitrogen, and other impurities and the number of oxygen vacancies is made to be higher than those in a semiconductor layer of a transistor is used for the conductive layer  3043 . 
     Note that the structures described in this embodiment can be combined with any of the structures described in the other embodiments as appropriate. 
     Example 1 
     In this example, an element structure, a fabrication method, and properties of a light-emitting element used in the light-emitting device of one embodiment of the present invention will be described. Note that  FIG. 18  illustrates an element structure of light-emitting elements described in this example, and Table 1 shows specific structures. Table 1 also shows color filters (CFs) combined with the light-emitting elements. A light-emitting element  1  is combined with a CF-R; a light-emitting element  2 , a CF-G; and each of light-emitting elements  3  and  4 , a CF-B.  FIG. 24  shows transmitting properties of these CFs. Chemical formulae of materials used in this example are shown below. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
             
            
               
                   
                   
                   
                 First 
                 First 
                   
                 First 
               
               
                 Reference 
                   
                   
                 hole-injection 
                 hole-transport 
                 Light-emitting 
                 electron-transport 
               
            
           
           
               
               
               
               
               
               
            
               
                 numeral 
                 First electrode 
                 layer 
                 layer 
                 layer (A) 
                 layer 
               
               
                 in FIG. 18 
                 901 
                 911a 
                 912a 
                 913a 
                 914a 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Light-emitting 
                 Ag—Pd—Cu 
                 ITSO 
                 PCPPn:MoO x   
                 PCPPn 
                 *1 
                 cgDBCzPA 
                 NBphen 
               
               
                 element 1(R) 
                 (200 nm) 
                 (110 nm) 
                 (1:0.5, 10 nm) 
                 (10 nm) 
                   
                 (10 nm) 
                 (15 nm) 
               
               
                 Light-emitting 
                   
                 ITSO 
                 PCPPn:MoO x   
               
               
                 element 2(G) 
                   
                 (45 nm) 
                 (1:0.5, 20 nm) 
               
               
                 Light-emitting 
                   
                 ITSO 
                 PCPPn:MoO x   
               
               
                 element 3(B1) 
                   
                 (10 nm) 
                 (1:0.5,12.5 nm) 
               
               
                 Light-emitting 
                   
                 ITSO 
                 PCPPn:MoO x   
               
               
                 element 4(B1.5) 
                   
                 (110 nm) 
                 (1:0.5, 16 nm) 
               
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Light-emitting layer (B) 
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 First 
                 Charge 
                 Second 
                 Second 
                 First 
                 Second 
                   
               
               
                 electron-injection 
                 generation 
                 hole-injection 
                 hole-transport 
                 light-emitting 
                 light-emitting 
               
               
                 layer 
                 layer 
                 layer 
                 layer 
                 layer 
                 layer 
               
               
                 915a 
                 904 
                 911b 
                 912b 
                 913(b1) 
                 913(b2) 
                 (Notes) 
               
               
                   
               
               
                 Li 2 O 
                 CuPc 
                 DBT3P-II:MoO x   
                 BPAFLP 
                 *2 
                 *3 
                 Light-emitting 
               
               
                 (0.1 nm) 
                 (2 nm) 
                 (1:0.5, 10 nm) 
                 (15 nm) 
                   
                   
                 element 1(R) 
               
               
                   
                   
                   
                   
                   
                   
                 Light-emitting 
               
               
                   
                   
                   
                   
                   
                   
                 element 2(G) 
               
               
                   
                   
                   
                   
                   
                   
                 Light-emitting 
               
               
                   
                   
                   
                   
                   
                   
                 element 3(B1) 
               
               
                   
                   
                   
                   
                   
                   
                 Light-emitting 
               
               
                   
                   
                   
                   
                   
                   
                 element 4(B1.5) 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Second 
                 Second 
                   
                   
                   
               
               
                 electron-transport 
                 electron-injection 
                 Second 
               
               
                 layer 
                 layer 
                 electrode 
               
               
                 914b 
                 915b 
                 903 
                 CF 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 2mDBTBPDBq-II 
                 NBphen 
                 LiF 
                 Ag:Mg 
                 ITO 
                 CF-R 
                 Light-emitting 
               
               
                 (25 nm) 
                 (15 nm) 
                 (1 nm) 
                 (1:0.1,25 nm) 
                 (70 nm) 
                   
                 element 1(R) 
               
               
                   
                   
                   
                   
                   
                 CF-G 
                 Light-emitting 
               
               
                   
                   
                   
                   
                   
                   
                 element 2(G) 
               
               
                   
                   
                   
                   
                   
                 CF-B 
                 Light-emitting 
               
               
                   
                   
                   
                   
                   
                   
                 element 3 (B1) 
               
               
                   
                   
                   
                   
                   
                 CF-B 
                 Light-emitting 
               
               
                   
                   
                   
                   
                   
                   
                 element 4(B1.5) 
               
               
                   
               
               
                 *1 cgDBCzPA:1,6BnfAPrn-03 (1:0.03, 25 nm) 
               
               
                 *2 2mDBTBPDBq-II:PCBBiF:[Ir(tBuppm) 3 ] (0.8:0.2:0.06, 20 nm) 
               
               
                 *3 2mDBTBPDBq-II:[Ir(dmdppr-P) 2 (dibm)] (1:0.04, 20 nm) 
               
            
           
         
       
     
                                                                               
&lt;&lt;Fabrication of Light-Emitting Elements&gt;&gt;
 
     Light-emitting elements described in this example each included, as illustrated in  FIG. 18 , a first electrode  901  over a substrate  900 , a first EL layer  902   a  over the first electrode  901 , a charge generation layer  904  over the first EL layer  902   a , a second EL layer  902   b  over the charge generation layer  904 , and a second electrode  903  over the second EL layer  902   b . Note that the light-emitting element  1  in this example was a light-emitting element emitting mainly red light and also referred to as a light-emitting element  1 (R). The light-emitting element  2  was a light-emitting element emitting mainly green light and also referred to as a light-emitting element  2 (G). The light-emitting element  3  and the light-emitting element  4  were each a light-emitting element emitting mainly blue light and were also referred to as a light-emitting element  3 (B 1 ) and a light-emitting element  4 (B 1 . 5 ), respectively. 
     First, the first electrode  901  was formed over the substrate  900 . The electrode area was set to 4 mm 2  (2 mm×2 mm). A glass substrate was used as the substrate  900 . The first electrode  901  was formed in the following manner: a 200-nm-thick alloy film of silver (Ag), palladium (Pd), and copper (Cu) (the alloy is also referred to as Ag—Pd—Cu) was formed by a sputtering method, and an ITSO was formed by a sputtering method. The ITSO was formed to have a thickness of 110 nm in the case of the light-emitting element  1 , 45 nm in the case of the light-emitting element  2 , 10 nm in the case of the light-emitting element  3 , and 110 nm in the case of the light-emitting element  4 . In this example, the first electrode  901  functioned as an anode. The first electrode  901  was a reflective electrode having a function of reflecting light. In this example, both the light-emitting element  3  and the light-emitting element  4  were light-emitting elements emitting blue light while having different optical path lengths between their electrodes. The light-emitting element  3  had an adjusted optical path length between its electrodes of 1 wavelength and the light-emitting element  4  had an adjusted optical path length between its electrodes of 1.5 wavelengths. 
     As pretreatment, a surface of the substrate was washed with water, baking was performed at 200° C. for one hour, and then UV ozone treatment was performed for 370 seconds. After that, the substrate was transferred into a vacuum evaporation apparatus where the pressure had been reduced to approximately 10 −4  Pa, and was subjected to vacuum baking at 170° C. for 60 minutes in a heating chamber of the vacuum evaporation apparatus, and then the substrate was cooled down for about 30 minutes. 
     Next, a first hole-injection layer  911   a  was formed over the first electrode  901 . After the pressure in the vacuum evaporation apparatus was reduced to 10 −4  Pa, the first hole-injection layer  911   a  was formed by co-evaporation to have a weight ratio of 3-[4-(9-phenanthryl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn) to molybdenum oxide of 1:0.5 and to have a thickness of 10 nm for the light-emitting element  1 ; 20 nm for the light-emitting element  2 ; 12.5 nm for the light-emitting element  3 ; and 16 nm for the light-emitting element  4 . 
     Then, a first hole-transport layer  912   a  was formed over the first hole-injection layer  911   a . As the first hole-transport layer  912   a , PCPPn was deposited by evaporation to a thickness of 10 nm. Note that the first hole-transport layers  912   a  in the first to fourth light-emitting elements were formed in a similar manner. It will not be mentioned if fabrication of the light-emitting elements had steps in common. 
     Next, a light-emitting layer (A)  913   a  was formed over the first hole-transport layer  912   a.    
     The light-emitting layer (A)  913   a  was formed to a thickness of 25 nm by co-evaporation using 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA) as a host material and using N,N-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03) as a guest material (fluorescent material) such that the weight ratio of cgDBCzPA to 1,6BnfAPrn-03 was 1:0.03. 
     Next, a first electron-transport layer  914   a  was formed over the light-emitting layer (A)  913   a . The first electron-transport layer  914   a  was formed in the following manner: cgDBCzPA and 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen) were sequentially deposited by evaporation to thicknesses of 10 nm and 15 nm, respectively. 
     After that, a first electron-injection layer  915   a  was formed over the first electron-transport layer  914   a . The first electron-injection layer  915   a  was formed to a thickness of 0.1 nm by evaporation of lithium oxide (Li 2 O). 
     Then, the charge generation layer  904  was formed over the first electron-injection layer  915   a . The charge generation layer  904  was formed to a thickness of 2 nm by evaporation of copper phthalocyanine (abbreviation: CuPc). 
     Next, a second hole-injection layer  911   b  was formed over the charge generation layer  904 . The second hole-injection layer  911   b  was formed to a thickness of 10 nm by co-evaporation such that the weight ratio of 4,4′,4″-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II) to molybdenum oxide was 1:0.5. 
     Then, a second hole-transport layer  912   b  was formed over the second hole-injection layer  911   b . The second hole-transport layer  912   b  was formed to a thickness of 15 nm by evaporation of 4-phenyl-4′-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP). 
     A light-emitting layer (B)  913   b  was formed over the second hole-transport layer  912   b . The light-emitting layer (B)  913   b  had a stacked-layer structure of a light-emitting layer (B 1 )  913 ( b   1 ) and a light-emitting layer (B 2 )  913 ( b   2 ). 
     The light-emitting layer (B 1 )  913 ( b   1 ) was formed to a thickness of 20 nm by co-evaporation using 2-[3′-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f h]quinoxaline (abbreviation: 2mDBTBPDBq-II) as a host material, using N-(1,1′-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF) as an assist material, and using tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) 3 ]) as a guest material (a phosphorescent material) such that the weight ratio of 2mDBTBPDBq-II:PCBBiF:[Ir(tBuppm) 3 ] was 0.8:0.2:0.06. The light-emitting layer (B 2 )  913 ( b   2 ) was formed to a thickness of 20 nm by co-evaporation using 2mDBTBPDBq-II as a host material and using bis {4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyrazinyl-κN]phenyl-κC}(2,6-dimethyl-3,5-heptanedionato-κ 2 O,O′)iridium(III) (abbreviation: [Ir(dmdppr-P) 2 (dibm)]) as a guest material (a phosphorescent material), such that the weight ratio of 2mDBTBPDBq-II to [Ir(dmdppr-P) 2 (dibm)] was 1:0.04. 
     Next, a second electron-transport layer  914   b  was formed over the light-emitting layer (B 2 )  913 ( b   2 ). The second electron-transport layer  914   b  was formed in the following manner: 2mDBTBPDBq-II and NBphen were sequentially deposited by evaporation to thicknesses of 25 nm and 15 nm, respectively. 
     Then, a second electron-injection layer  915   b  was formed over the second electron-transport layer  914   b . The second electron-injection layer  915   b  was formed to a thickness of 1 nm by evaporation of lithium fluoride (LiF). 
     Then, the second electrode  903  was formed over the second electron-injection layer  915   b  in the following manner: silver (Ag) and magnesium (Mg) were formed to a thickness of 25 nm by co-evaporation at a volume ratio of Ag to Mg of 1:0.1, and then an indium tin oxide (ITO) was formed to a thickness of 70 nm by a sputtering method. In this example, the second electrode  903  functioned as a cathode. Moreover, the second electrode  903  was a transflective electrode having functions of transmitting light and reflecting light. 
     Through the above steps, the light-emitting elements in each of which the EL layers were provided between a pair of electrodes over the substrate  900  were formed. The first hole-injection layer  911   a , the first hole-transport layer  912   a , the light-emitting layer (A)  913   a , the first electron-transport layer  914   a , the first electron-injection layer  915   a , the second hole-injection layer  911   b , the second hole-transport layer  912   b , the light-emitting layer (B)  913   b , the second electron-transport layer  914   b , and the second electron-injection layer  915   b  described above were functional layers forming the EL layers of one embodiment of the present invention. Furthermore, in all the evaporation steps in the above fabrication method, evaporation was performed by a resistance-heating method. 
     Each of the light-emitting elements formed in this example was sealed between the substrate  900  and a substrate  905  as illustrated in  FIG. 18 . The substrate  905  was provided with a color filter  906 . The sealing between the substrate  900  and the substrate  905  was performed in such a manner that the substrate  905  was fixed to the substrate  900  with a sealing material in a glove box containing a nitrogen atmosphere, a sealant was applied so as to surround the light-emitting element formed over the substrate  900 , and then irradiation with 365-nm ultraviolet light at 6 J/cm 2  was performed and heat treatment was performed at 80° C. for 1 hour. 
     The light-emitting elements formed in this example each have a structure in which light is emitted in the direction indicated by the arrow from the second electrode  903  side of the light-emitting element. 
     &lt;&lt;Operation Characteristics of Light-Emitting Elements&gt;&gt; 
     Operation characteristics of the formed light-emitting elements were measured. Note that the measurement was performed at room temperature (in an atmosphere kept at 25° C.). The results are shown in  FIG. 19  to  FIG. 22 .  FIG. 23  shows emission spectra when current at a current density of 2.5 mA/cm 2  was applied to the light-emitting elements. The emission spectra were measured with a multi-channel spectrometer (PMA-12 manufactured by Hamamatsu Photonics K.K.). As shown in  FIG. 23 , the emission spectrum of the light-emitting element  1  which emits red light has a peak at around 635 nm, the emission spectrum of the light-emitting element  2  which emits green light has a peak at around 521 nm, and the emission spectra of the light-emitting elements  3  and  4  which emit blue light each have a peak at around 453 nm. The spectrum shapes were narrowed. In this example, the measurement results of light emission obtained from a combination of light-emitting elements and color filters are shown. 
       FIG. 24  shows transmission spectra of the red color filter (CF—R) used in combination with the light-emitting element  1 (R), the green color filter (CF-G) used in combination with the light-emitting element  2 (G), and the blue color filter (CF-B) used in combination with the light-emitting element  3 (B 1 ) or  4 (B 1 . 5 ).  FIG. 24  shows that the 600-nm light transmittance of the CF—R is 52%, which is lower than or equal to 60%, whereas the 650-nm light transmittance of the CF—R is 89%, which is higher than or equal to 70%. In addition, the 480-nm light transmittance and 580-nm light transmittance of the CF-G are 26% and 52%, respectively, which are lower than or equal to 60%, whereas the 530-nm light transmittance of the CF-G is 72%, which is higher than or equal to 70%. Furthermore, the 510-nm light transmittance of the CF-B is 60%, which is lower than or equal to 60%, whereas the 450-nm light transmittance of the CF-B is 80%, which is higher than or equal to 70%. 
     The results of the chromaticities (x, y) of the light-emitting elements formed in this example (the light-emitting elements  1  to  3 ) measured with a luminance colorimeter (BM-5A manufactured by TOPCON CORPORATION) are shown in Table 2 below. The chromaticities of the light-emitting elements  1 (R),  2 (G), and  3 (B 1 ) were measured at luminances of approximately 730 cd/m 2 , approximately 1800 cd/m 2 , and approximately 130 cd/m 2 , respectively. The luminance ratio is a value such that white light emission close to D65 (light having chromaticity coordinates of (x, y)=(0.313, 0.329)) can be obtained by summing the luminance of R, the luminance of G, and the luminance of B. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 x 
                 y 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Light-emitting 
                 0.697 
                 0.297 
               
               
                   
                 element 1(R) 
               
               
                   
                 Light-emitting 
                 0.186 
                 0.778 
               
               
                   
                 element 2(G) 
               
               
                   
                 Light-emitting 
                 0.142 
                 0.046 
               
               
                   
                 element 3(B1) 
               
               
                   
                   
               
            
           
         
       
     
     On the basis of the results in Table 2, the BT.2020 area ratio and the BT.2020 coverage calculated from the chromaticities (x, y) were 93% and 91%, respectively. Note that an area A of a triangle formed by connecting the CIE chromaticity coordinates (x, y) of RGB which fulfill the BT.2020 standard and an area B of a triangle formed by connecting the CIE chromaticity coordinates (x, y) of the three light-emitting elements in this example were calculated to obtain the area ratio (B/A). The coverage is a value which represents how much percentage of the BT.2020 standard color gamut (the inside of the above triangle) can be reproduced using a combination of the chromaticities of the three light-emitting elements in this example. 
     The results of the chromaticities (x, y) of the light-emitting elements  1 ,  2 , and  4  measured with a luminance colorimeter among the light-emitting elements formed in this example are shown in Table 3 below. The chromaticities of the light-emitting elements  1 (R),  2 (G), and  4 (B 1 . 5 ) were measured at luminances of approximately 550 cd/m 2 , approximately 1800 cd/m 2 , and approximately 130 cd/m 2 , respectively. The luminance ratio is a value such that white light emission close to D65 can be obtained by summing the luminance of R, the luminance of G, and the luminance of B. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 x 
                 y 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Light-emitting 
                 0.697 
                 0.297 
               
               
                   
                 element 1(R) 
               
               
                   
                 Light-emitting 
                 0.186 
                 0.778 
               
               
                   
                 element 2(G) 
               
               
                   
                 Light-emitting 
                 0.156 
                 0.042 
               
               
                   
                 element 4(B1.5) 
               
               
                   
                   
               
            
           
         
       
     
     On the basis of the results in Table 3, the BT.2020 area ratio and the BT.2020 coverage calculated from the chromaticities (x, y) were 92% and 90%, respectively. Even such a structure having improved luminous efficiency of blue light can achieve extremely wide-range color reproducibility. 
     The above results show that, in this example, the light-emitting element  1 (R) has a chromaticity x of greater than 0.680 and less than or equal to 0.720 and a chromaticity y of greater than or equal to 0.260 and less than or equal to 0.320, the light-emitting element  2 (G) has a chromaticity x of greater than or equal to 0.130 and less than or equal to 0.250 and a chromaticity y of greater than 0.710 and less than or equal to 0.810, and each of the light-emitting element  3 (B 1 ) and the light-emitting element  4 (B 31 . 5 ) has a chromaticity x of greater than or equal to 0.120 and less than or equal to 0.170 and a chromaticity y of greater than or equal to 0.020 and less than 0.060. The light-emitting element  1 (R) has a chromaticity x of greater than 0.680 and thus has a better red chromaticity than the DCI-P3 standard. The light-emitting element  2 (G) has a chromaticity y of greater than 0.71 and thus has a better green chromaticity than the DCI-P3 standard and the NTSC standard. In addition, the light-emitting elements  3 (B 1 ) and  4 (B 1 . 5 ) each have a chromaticity y of less than 0.06 and thus have a better blue chromaticity than the DCI-P3 standard. 
     Note that the chromaticities (x, y) of the light-emitting elements  1 ,  2 ,  3 , and  4  calculated using the values of the emission spectra shown in  FIG. 23  are (0.693, 0.303), (0.202, 0.744), (0.139, 0.056), and (0.160, 0.057), respectively. Therefore, when the chromaticities of a combination of the light-emitting elements  1 (R),  2 (G), and  3 (B 1 ) are calculated using the emission spectra, the BT.2020 area ratio is 86% and the BT.2020 coverage is 84%. In addition, when the chromaticities of a combination of the light-emitting elements  1 (R),  2 (G), and  4 (B 1 . 5 ) are calculated using the emission spectra, the BT.2020 area ratio is 84% and the BT.2020 coverage is 82%. 
     Example 2 
     In this example, an element structure, a forming method, and properties of a light-emitting element used in the light-emitting device of one embodiment of the present invention will be described. Note that  FIG. 18  illustrates an element structure of light-emitting elements described in this example, and Table 4 shows specific structures. Chemical formulae of materials used in this example are shown below. The color filters whose transmission spectra are shown in  FIG. 24  were used. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 4 
               
               
                   
                   
               
             
            
               
                   
                 First 
                 First 
                   
                 First 
               
            
           
           
               
               
               
               
               
               
            
               
                 Reference 
                 First 
                 hole-injection 
                 hole-transport 
                 Light-emitting 
                 electron-transport 
               
               
                 numeral 
                 electrode 
                 layer 
                 layer 
                 layer (A) 
                 layer 
               
            
           
           
               
               
               
               
               
               
               
            
               
                 in FIG. 18 
                 901 
                 911a 
                 912a 
                 913a 
                 9 
                 14a 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Light-emitting 
                 Ag—Pd—Cu 
                 ITSO 
                 PCPPn:MoO x   
                 PCPPn 
                 *1 
                 cgDBCzPA 
                 NBphen 
               
               
                 element 5(R) 
                 (200 nm) 
                 (110 nm) 
                 (1:0.5, 10 nm) 
                 (10 nm) 
                   
                 (10 nm) 
                 (15 nm) 
               
               
                 Light-emitting 
                   
                 ITSO 
                 PCPPn:MoO x   
               
               
                 element 6(G) 
                   
                 (45 nm) 
                 (1:0.5, 20 nm) 
               
               
                 Light-emitting 
                   
                 ITSO 
                 PCPPn:MoO x   
               
               
                 element 7(B1) 
                   
                 (10 nm) 
                 (1:0.5, 12.5 nm) 
               
               
                 Light-emitting 
                   
                 ITSO 
                 PCPPn:MoO x   
               
               
                 element 8(B1.5) 
                   
                 (110 nm) 
                 (1:0.5, 19 nm) 
               
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Light-emitting layer (B) 
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 First 
                 Charge 
                 Second 
                 Second 
                 First 
                 Second 
                   
               
               
                 electron-injection 
                 generation 
                 hole-injection 
                 hole-transport 
                 light-emitting 
                 light-emitting 
               
               
                 layer 
                 layer 
                 layer 
                 layer 
                 layer 
                 layer 
               
               
                 915a 
                 904 
                 911b 
                 912b 
                 913(b1) 
                 913(b2) 
                 (Notes) 
               
               
                   
               
               
                 Li 2 O 
                 CuPc 
                 DBT3P-II:MoO x   
                 BPAFLP 
                 *2 
                 *3 
                 Light-emitting 
               
               
                 (0.1 nm) 
                 (2 nm) 
                 (10.5, 10 nm) 
                 (15 nm) 
                   
                   
                 element 5(R) 
               
               
                   
                   
                   
                   
                   
                   
                 Light-emitting 
               
               
                   
                   
                   
                   
                   
                   
                 element 6(G) 
               
               
                   
                   
                   
                   
                   
                   
                 Light-emitting 
               
               
                   
                   
                   
                   
                   
                   
                 element 7(B1) 
               
               
                   
                   
                   
                   
                   
                   
                 Light-emitting 
               
               
                   
                   
                   
                   
                   
                   
                 element 8(B1.5) 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Second 
                   
                   
                   
                   
               
               
                 electron-transport 
                 Second electron- 
               
               
                 layer 
                 injection layer 
                 Second electrode 
               
               
                 914b 
                 915b 
                 903 
                 CF 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 2mDBTBPDBq-II 
                 NBphen 
                 LiF 
                 Ag:Mg 
                 ITO 
                 CF-R 
                 Light-emitting 
               
               
                 (25 nm) 
                 (15 nm) 
                 (1 nm) 
                 (1:0.1, 30 nm) 
                 (70 nm) 
                   
                 element 5(R) 
               
               
                   
                   
                   
                   
                   
                 CF-G 
                 Light-emitting 
               
               
                   
                   
                   
                   
                   
                   
                 element 6(G) 
               
               
                   
                   
                   
                   
                   
                 CF-B 
                 Light-emitting 
               
               
                   
                   
                   
                   
                   
                   
                 element 7(B1) 
               
               
                   
                   
                   
                   
                   
                 CF-B 
                 Light-emitting 
               
               
                   
                   
                   
                   
                   
                   
                 element 8(B1.5) 
               
               
                   
               
               
                 *1 cgDBCzPA:1,6BnfAPrn-03 (1:0.03, 25 nm) 
               
               
                 *2 2mDBTBPDBq-II:PCBBiF:[Ir(tBuppm) 3 ] (0.8:0.2:0.06, 20 nm) 
               
               
                 *3 2mDBTBPDBq-II:[Ir(dmdppr-P) 2 (dibm)] (1:0.04, 20 nm) 
               
            
           
         
       
     
                                                                               
&lt;&lt;Fabrication of Light-Emitting Elements&gt;&gt;
 
     Light-emitting elements described in this example each included, as illustrated in  FIG. 18 , the first electrode  901  over the substrate  900 , the first EL layer  902   a  over the first electrode  901 , the charge generation layer  904  over the first EL layer  902   a , the second EL layer  902   b  over the charge generation layer  904 , and the second electrode  903  over the second EL layer  902   b  as in Example 1. Note that a light-emitting element  5  in this example was a light-emitting element emitting mainly red light and also referred to as a light-emitting element  5 (R). A light-emitting element  6  was a light-emitting element emitting mainly green light and also referred to as a light-emitting element  6 (G). A light-emitting element  7  and a light-emitting element  8  were each a light-emitting element emitting mainly blue light and were also referred to as a light-emitting element  7 (B 1 ) and a light-emitting element  8 (B 1 . 5 ), respectively. 
     In the light-emitting elements in this example, the thicknesses of the layers formed in fabricating the elements were different from each other. However, the layers can be formed in manners similar to those in Example 1 using the same materials; thus, Example 1 is referred to and description is omitted in this example. 
     &lt;&lt;Operation Characteristics of Light-Emitting Elements&gt;&gt; 
     Operation characteristics of the formed light-emitting elements were measured. Note that the measurement was performed at room temperature (in an atmosphere kept at 25° C.). The results are shown in  FIG. 25  to  FIG. 28 .  FIG. 29  shows emission spectra when current at a current density of 2.5 mA/cm 2  was applied to the light-emitting elements. The emission spectra were measured with a multi-channel spectrometer (PMA-12 manufactured by Hamamatsu Photonics K.K.). As shown in  FIG. 29 , the emission spectrum of the light-emitting element  5  which emits red light has a peak at around 635 nm, the emission spectrum of the light-emitting element  6  which emits green light has a peak at around 530 nm, and the emission spectra of the light-emitting elements  7  and  8  which emit blue light have peaks at around 464 nm and 453 nm, respectively. The spectrum shapes were narrowed. In this example, the measurement results of light emission obtained from a combination of light-emitting elements and color filters are shown. 
     Next, the results of the chromaticities (x, y) of the light-emitting elements formed in this example (the light-emitting elements  5  to  7 ) measured with a luminance colorimeter (BM-5A manufactured by TOPCON CORPORATION) are shown in Table 5 below. The chromaticities of the light-emitting elements  5 (R),  6 (G), and  7 (B 1 ) were measured at luminances of approximately 650 cd/m 2 , approximately 1900 cd/m 2 , and approximately 140 cd/m 2 , respectively. The luminance ratio is a value such that white light emission close to D65 can be obtained by summing the luminance of R, the luminance of G, and the luminance of B. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 5 
               
               
                   
                   
               
               
                   
                 x 
                 y 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Light-emitting 
                 0.700 
                 0.294 
               
               
                   
                 element 5(R) 
               
               
                   
                 Light-emitting 
                 0.175 
                 0.793 
               
               
                   
                 element 6(G) 
               
               
                   
                 Light-emitting 
                 0.142 
                 0.039 
               
               
                   
                 element 7(B1) 
               
               
                   
                   
               
            
           
         
       
     
     On the basis of the results in Table 5, the BT.2020 area ratio and the BT.2020 coverage calculated from the chromaticities (x, y) were 97% and 95%, respectively. 
     The results of the chromaticities (x, y) of the light-emitting elements  5  to  8  among the light-emitting elements formed in this example with a luminance colorimeter are shown in Table 6 below. The chromaticities of the light-emitting elements  5 (R),  6 (G), and  8 (B 1 . 5 ) were measured at luminances of approximately 650 cd/m 2 , approximately 1900 cd/m 2 , and approximately 170 cd/m 2 , respectively. The luminance ratio is a value such that white light emission close to D65 can be obtained by summing the luminance of R, the luminance of G, and the luminance of B. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 6 
               
               
                   
                   
               
               
                   
                 x 
                 y 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Light-emitting 
                 0.700 
                 0.294 
               
               
                   
                 element 5(R) 
               
               
                   
                 Light-emitting 
                 0.175 
                 0.793 
               
               
                   
                 element 6(G) 
               
               
                   
                 Light-emitting 
                 0.153 
                 0.046 
               
               
                   
                 element 8(B1.5) 
               
               
                   
                   
               
            
           
         
       
     
     On the basis of the results in Table 6, the BT.2020 area ratio and the BT.2020 coverage calculated from the chromaticities (x, y) were 95% and 93%, respectively. Even such a structure having improved luminous efficiency of blue light can achieve extremely wide-range color reproducibility. 
     The above results show that, in this example, the light-emitting element  5 (R) has a chromaticity x of greater than 0.680 and less than or equal to 0.720 and a chromaticity y of greater than or equal to 0.260 and less than or equal to 0.320, the light-emitting element  6 (G) has a chromaticity x of greater than or equal to 0.130 and less than or equal to 0.250 and a chromaticity y of greater than 0.710 and less than or equal to 0.810, and each of the light-emitting element  7 (B 1 ) and the light-emitting element  8 (B 1 . 5 ) has a chromaticity x of greater than or equal to 0.120 and less than or equal to 0.170 and a chromaticity y of greater than or equal to 0.020 and less than 0.060. The light-emitting element  6 (G) has a chromaticity y of greater than 0.71, and thus has a better green chromaticity than the DCI-P3 standard and the NTSC standard. In addition, the light-emitting elements  7 (B 1 ) and  8 (B 1 . 5 ) each have a chromaticity y of less than 0.06, and thus have a better blue chromaticity than the DCI-P3 standard. 
     Note that the chromaticities (x, y) of the light-emitting elements  5 ,  6 ,  7 , and  8  calculated using the values of the emission spectra shown in  FIG. 29  are (0.696, 0.300), (0.185, 0.760), (0.140, 0.048), and (0.154, 0.056), respectively. Therefore, when the chromaticities of a combination of the light-emitting elements  5 (R),  6 (G), and  7 (B 1 ) are calculated using the emission spectra, the BT.2020 area ratio is 91% and the BT.2020 coverage is 89%. In addition, when the chromaticities of a combination of the light-emitting elements  5 (R),  6 (G), and  8 (B 1 . 5 ) are calculated using the emission spectra, the BT.2020 area ratio is 88% and the BT.2020 coverage is 86%. 
     Reference Example 
     In this reference example, a synthesis method of bis{4,6-dimethyl-2-[5-(4-cyano-2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ 2 O,O′)iridium(III) (abbreviation: [Ir(dmdppr-dmCP) 2 (dpm)]) (Structural formula (100)), which is an organometallic complex and a light-emitting substance that can be used for the light-emitting layer in the light-emitting element of one embodiment of the present invention, is described. The emission spectrum of the organometallic complex has a peak of greater than or equal to 600 nm and less than or equal to 700 nm. The structure of [Ir(dmdppr-dmCP) 2 (dpm)] is shown below. 
     
       
         
         
             
             
         
       
     
     Step 1: Synthesis of 5-hydroxy-2,3-(3,5-dimethylphenyl)pyrazine 
     First, 5.27 g of 3,3′,5,5′-tetramethylbenzyl, 2.61 g of glycinamide hydrochloride, 1.92 g of sodium hydroxide, and 50 mL of methanol were put into a three-necked flask equipped with a reflux pipe, and the air in the flask was replaced with nitrogen. After that, the mixture was stirred at 80° C. for 7 hours to cause a reaction. Then, 2.5 mL of 12M hydrochloric acid was added thereto and stirring was performed for 30 minutes. Then, 2.02 g of potassium bicarbonate was added, and stirring was performed for 30 minutes. After the resulting suspension was subjected to suction filtration, the obtained solid was washed with water and methanol to give an objective pyrazine derivative as milky white powder in a yield of 79%. A synthesis scheme of Step 1 is shown in (a-1). 
     
       
         
         
             
             
         
       
     
     Step 2: Synthesis of 5,6-bis(3,5-dimethylphenyl)pyrazin-2-yl trifluoromethanesulfonate 
     Next, 4.80 g of 5-hydroxy-2,3-(3,5-dimethylphenyl)pyrazine which was obtained in Step 1, 4.5 mL of triethylamine, and 80 mL of dehydrated dichloromethane were put into a three-necked flask, and the air in the flask was replaced with nitrogen. The flask was cooled down to −20° C. Then, 3.5 mL of trifluoromethanesulfonic anhydride was dropped therein, and stirring was performed at room temperature for 17.5 hours. After that, the flask was cooled down to 0° C. Then, 0.7 mL of trifluoromethanesulfonic anhydride was further dropped therein, and stirring was performed at room temperature for 22 hours to cause a reaction. To the reaction solution, 50 mL of water and 5 mL of IM hydrochloric acid were added and then, dichloromethane was added, so that a substance contained in the reaction solution was extracted in the dichloromethane. A saturated aqueous solution of sodium hydrogencarbonate and saturated saline were added to this dichloromethane for washing. Then, magnesium sulfate was added thereto for drying. After being dried, the solution was filtered, and the filtrate was concentrated and the obtained residue was purified by silica gel column chromatography using toluene:hexane=1:1 (volume ratio) as a developing solvent, to give an objective pyrazine derivative as yellow oil in a yield of 96%. A synthesis scheme of Step 2 is shown in (a-2). 
     
       
         
         
             
             
         
       
     
     Step 3: Synthesis of 5-(4-cyano-2,6-dimethylphenyl)-2,3-bis(3,5-dimethylphenyl)pyrazine (abbreviation: Hdmdppr-dmCP) 
     Next, 2.05 g of 5,6-bis(3,5-dimethylphenyl)pyrazin-2-yl trifluoromethanesulfonate which was obtained in Step 2, 1.00 g of 4-cyano-2,6-dimethylphenylboronic acid, 3.81 g of tripotassium phosphate, 40 mL of toluene, and 4 mL of water were put into a three-necked flask, and the air in the flask was replaced with nitrogen. The mixture in the flask was degassed by being stirred under reduced pressure, 0.044 g of tris(dibenzylideneacetone)dipalladium(0) and 0.084 g of tris(2,6-dimethoxyphenyl)phosphine were then added thereto, and the mixture was refluxed for 7 hours. Water was added to the reaction solution, and then toluene was added, so that the material contained in the reaction solution was extracted in the toluene. Saturated saline was added to the toluene solution, and the toluene solution was washed. Then, magnesium sulfate was added thereto for drying. After being dried, the solution was filtered, and the filtrate was concentrated and the obtained residue was purified by silica gel column chromatography using hexane: ethyl acetate=5:1 (volume ratio) as a developing solvent, to give an objective pyrazine derivative Hdmdppr-dmCP as white powder in a yield of 90%. A synthesis scheme of Step 3 is shown in (a-3). 
     
       
         
         
             
             
         
       
     
     Step 4: Synthesis of di-μ-chloro-tetrakis {4,6-dimethyl-2-[5-(4-cyano-2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}diiridium(III) (abbreviation: [Ir(dmdppr-dmCP) 2 Cl] 2 ) 
     Next, 15 mL of 2-ethoxyethanol, 5 mL of water, 1.74 g of Hdmdppr-dmCP (abbreviation) which was obtained in Step 3, and 0.60 g of iridium chloride hydrate (IrCl 3 ×H 2 O) (produced by FURUYA METAL Co., Ltd.) were put into a recovery flask equipped with a reflux pipe, and the air in the flask was replaced with argon. After that, microwave irradiation (2.45 GHz, 100 W) was performed for an hour to cause a reaction. The solvent was distilled off, and then the obtained residue was suction-filtered and washed with hexane to give a dinuclear complex [Ir(dmdppr-dmCP) 2 Cl] 2  as brown powder in a yield of 89%. A synthesis scheme of Step 4 is shown in (a-4). 
     
       
         
         
             
             
         
       
     
     &lt;Step 5: Synthesis of bis{4,6-dimethyl-2-[5-(4-cyano-2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ 2 O,O′)iridium(III) (abbreviation: [Ir(dmdppr-dmCP) 2 (dpm)])&gt; 
     Furthermore, 30 mL of 2-ethoxyethanol, 0.96 g of [Ir(dmdppr-dmCP) 2 Cl] 2  that is the dinuclear complex obtained in Step 4, 0.26 g of dipivaloylmethane (abbreviation: Hdpm), and 0.48 g of sodium carbonate were put into a recovery flask equipped with a reflux pipe, and the air in the flask was replaced with argon. After that, microwave irradiation (2.45 GHz, 100 W) was performed for 60 minutes. Moreover, 0.13 g of Hdpm was added thereto, and the reaction container was subjected to microwave irradiation (2.45 GHz, 120 W) for 60 minutes to cause a reaction. The solvent was distilled off, and the obtained residue was purified by silica gel column chromatography using dichloromethane and hexane as a developing solvent in a volume ratio of 1:1. The obtained residue was further purified by silica gel column chromatography using dichloromethane as a developing solvent, and then recrystallization was performed with a mixed solvent of dichloromethane and methanol to give [Ir(dmdppr-dmCP) 2 (dpm)] which is the organometallic complex as red powder in a yield of 37%. By a train sublimation method, 0.39 g of the obtained red powder was purified. The sublimation purification was carried out at 300° C. under a pressure of 2.6 Pa with a flow rate of an argon gas at 5 mL/min. After the purification by sublimation, a red solid, which was an objective substance, was obtained in a yield of 85%. A synthetic scheme of Step 5 is shown in (a-5). 
     
       
         
         
             
             
         
       
     
     Note that results of the analysis of the red powder obtained in Step 5 by nuclear magnetic resonance spectrometry ( 1 H-NMR) are given below. These results revealed that [Ir(dmdppr-dmCP) 2 (dpm)], which is the organometallic complex represented by Structural Formula (100), was obtained in this synthesis example. 
       1 H-NMR. δ (CD 2 Cl 2 ): 0.91 (s, 18H), 1.41 (s, 6H), 1.95 (s, 6H), 2.12 (s, 12H), 2.35 (s, 12H), 5.63 (s, 1H), 6.49 (s, 2H), 6.86 (s, 2H), 7.17 (s, 2H), 7.34 (s, 4H), 7.43 (s, 4H), 8.15 (s, 2H). 
     Example 3 
     In this example, an element structure, a fabrication method, and properties of a light-emitting element used in the light-emitting device of one embodiment of the present invention will be described. Note that  FIG. 30  illustrates an element structure of light-emitting elements described in this example, and Table 7 shows specific structures. Chemical formulae of materials used in this example are shown below. Note that “ote tha the table represents an alloy film of silver (Ag), palladium (Pd), and copper (Cu) (i.e., an Ag—Pd—Cu film). 
     
       
         
           
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 7 
               
               
                   
                   
               
               
                   
                   
                   
                   
                   
                   
                 Electron- 
                   
               
               
                   
                 First 
                 Hole-injection 
                 Hole-transport 
                 Light-emitting 
                 Electron-transport 
                 injection 
                 Second 
               
               
                   
                 electrode 
                 layer 
                 layer 
                 layer 
                 layer 
                 layer 
                 electrode 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 Light-emitting 
                 APC\ITO 
                 DBT3P-II:MoO x   
                 BPAFLP 
                 * 
                 2mDBTBPDBq-II 
                 NBphen 
                 LiF 
                 Ag:Mg 
                 ITO 
               
               
                 element 9(R) 
                 (10 nm) 
                 (1:0.5, 15 nm) 
                 (15 nm) 
                   
                 (30 nm) 
                 (20 nm) 
                 (1 nm) 
                 (1:0.1, 30 nm) 
                 (70 nm) 
               
               
                 Light-emitting 
                 APC\ITO 
                 DBT3P-II:MoO x   
                 BPAFLP 
                 ** 
                 2mDBTBPDBq-II 
                 Bphen 
                 LiF 
                 Ag:Mg 
                 ITO 
               
               
                 element 10(G) 
                 (110 nm) 
                 (1:0.5, 25 nm) 
                 (15 nm) 
                   
                 (15 nm) 
                 (15 nm) 
                 (1 nm) 
                 (1:0.1, 30 nm) 
                 (70 nm) 
               
               
                 Light-emitting 
                 APC\ITO 
                 PCPPn:MoO x   
                 PCPPn 
                 *** 
                 cgDBCzPA 
                 Nbphen 
                 LiF 
                 Ag:Mg 
                 ITO 
               
               
                 element 11(B) 
                 (85 nm) 
                 (1:0.5, 37.5 nm) 
                 (15 nm) 
                   
                 (5 nm) 
                 (15 nm) 
                 (1 nm) 
                 (1:0.1, 30 nm) 
                 (70 nm) 
               
               
                   
               
               
                 * 2mDBTBPDBq-II:PCBBiF:[Ir(dmdppr-P) 2 (dibm)] (0.7:0.3:0.04 (20 nm)\0.8:0.2:0.04 (20 nm)) 
               
               
                 ** 2mDBTBPDBq-II:PCBBiF:[Ir(tBuppm) 3 ] (0.7:0.3:0.06 (20 nm)\0.8:0.2:0.06 (20 nm)) 
               
               
                 *** cgDBCzPA:1,6BnfAPrn-03 (1:0.03 (25 nm)) 
               
            
           
         
       
     
                                                             
&lt;&lt;Fabrication of Light-Emitting Elements&gt;&gt;
 
     Light-emitting elements described in this example each included, as illustrated in  FIG. 30 , a first electrode  1901  over a substrate  1900 , an EL layer  1902  over the first electrode  1901 , and a second electrode  1903  over the EL layer  1902 . In the EL layer  1902 , a hole-injection layer  1911 , a hole-transport layer  1912 , a light-emitting layer  1913 , an electron-transport layer  1914 , and an electron-injection layer  1915  are stacked in this order from the first electrode  1901  side. Note that a light-emitting element  9  in this example was a light-emitting element emitting mainly red light and also referred to as a light-emitting element  9 (R). A light-emitting element  10  was a light-emitting element emitting mainly green light and also referred to as a light-emitting element  10 (G). A light-emitting element  11  was a light-emitting element emitting mainly blue light and also referred to as a light-emitting element  11 (B). 
     The light-emitting elements described in this example have element structures different from those of the light-emitting elements described in Examples 1 and 2. Meanwhile, functional layers included in the light-emitting elements can be formed in a manner similar to that described in Example 1; thus, Example 1 is referred to and the description is omitted in this example. 
     &lt;&lt;Operation Characteristics of Light-Emitting Elements&gt;&gt; 
     Operation characteristics of the formed light-emitting elements were measured. Note that the measurement was performed at room temperature (in an atmosphere kept at 25° C.). The results are shown in  FIG. 31  to  FIG. 34 .  FIG. 35  shows emission spectra when current at a current density of 2.5 mA/cm 2  was applied to the light-emitting elements. The emission spectra were measured with a multi-channel spectrometer (PMA-12 manufactured by Hamamatsu Photonics K.K.). As shown in  FIG. 35 , the emission spectrum of the light-emitting element  9  which emits red light has a peak at around 632 nm, the emission spectrum of the light-emitting element  10  which emits green light has a peak at around 524 nm, and the emission spectrum of the light-emitting element  11  which emits blue light has a peak at around 462 nm. The spectrum shapes were narrowed. 
     Table 8 below shows the chromaticities (x, y) of the light-emitting elements (the light-emitting elements  9 ,  10 , and  11 ) fabricated in this example measured with a luminance colorimeter (BM-5AS, manufactured by TOPCON CORPORATION). Note that the chromaticities of the light-emitting elements were measured at a luminance of approximately 1000 cd/m 2 .  FIG. 36  shows the CIE1931 chromaticity coordinates (x,y chromaticity coordinates) listed in Table 8. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 8 
               
               
                   
                   
               
               
                   
                 x 
                 y 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Light-emitting 
                 0.705 
                 0.295 
               
               
                   
                 element 9(R) 
               
               
                   
                 Light-emitting 
                 0.174 
                 0.794 
               
               
                   
                 element 10(G) 
               
               
                   
                 Light-emitting 
                 0.141 
                 0.041 
               
               
                   
                 element 11(B) 
               
               
                   
                   
               
            
           
         
       
     
     Although the chromaticities (x, y) of the light-emitting elements obtained here are chromaticities on the CIE1931 chromaticity coordinates (x,y chromaticity coordinates) as described above, chromaticities on the CIE1976 chromaticity coordinates (u′,v′ chromaticity coordinates), which are defined so that the perceived color differences may correspond to distances equivalent in the color space, can be obtained with the use of the following conversion equations (1). 
     
       
         
           
             
               
                 
                   [ 
                   
                     Formula 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     1 
                   
                   ] 
                 
               
               
                 
                     
                 
               
             
             
               
                 
                   
                     
                       
                         
                           
                             u 
                             ′ 
                           
                           = 
                           
                             4 
                             ⁢ 
                             
                               x 
                               / 
                               
                                 ( 
                                 
                                   
                                     12 
                                     ⁢ 
                                     y 
                                   
                                   - 
                                   
                                     2 
                                     ⁢ 
                                     x 
                                   
                                   + 
                                   3 
                                 
                                 ) 
                               
                             
                           
                         
                       
                     
                     
                       
                         
                           
                             v 
                             ′ 
                           
                           = 
                           
                             9 
                             ⁢ 
                             
                               y 
                               / 
                               
                                 ( 
                                 
                                   
                                     12 
                                     ⁢ 
                                     y 
                                   
                                   - 
                                   
                                     2 
                                     ⁢ 
                                     x 
                                   
                                   + 
                                   3 
                                 
                                 ) 
                               
                             
                           
                         
                       
                     
                   
                   } 
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
     The chromaticities of the light-emitting elements in this example on the CIE1976 chromaticity coordinates (u′,v′ chromaticity coordinates) are listed in Table 9 below. Table 9 also shows the chromaticity coordinates in accordance with the BT.2020 standard for comparison. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 9 
               
             
            
               
                   
                   
               
               
                   
                 Example 3 
                   
                 BT.2020 
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 u′ 
                 v′ 
                 u′ 
                 v′ 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 R 
                 0.552 
                 0.517 
                 0.557 
                 0.517 
               
               
                 G 
                 0.057 
                 0.587 
                 0.056 
                 0.587 
               
               
                 B 
                 0.174 
                 0.120 
                 0.159 
                 0.126 
               
               
                   
               
            
           
         
       
     
     The BT.2020 area ratio calculated from the chromaticities (u′, v′) in Table 9 was 100%.  FIG. 37  shows the chromaticity coordinates listed in Table 9. 
     According to the above results, the use of the light-emitting elements described in this example can offer extremely wide-range color reproducibility. 
     Example 4 
     In this example, an element structure and properties of a light-emitting element used in the light-emitting device of one embodiment of the present invention will be described. Note that  FIG. 30  illustrates an element structure of light-emitting elements described in this example, and Table 10 shows specific structures. Chemical formulae of materials used in this example are shown below. 
     
       
         
           
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 10 
               
               
                   
                   
               
               
                   
                   
                   
                   
                   
                   
                 Electron- 
                   
               
               
                   
                 First 
                 Hole-injection 
                 Hole-transport 
                 Light-emitting 
                 Electron-transport 
                 injection 
                 Second 
               
               
                   
                 electrode 
                 layer 
                 layer 
                 layer 
                 layer 
                 layer 
                 electrode 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 Light-emitting 
                 APC\ITO 
                 DBT3P-II:MoO x   
                 BPAFLP 
                 * 
                 2mDBTBPDBq-II 
                 NBphen 
                 LiF 
                 Ag:Mg 
                 ITO 
               
               
                 element 12(R) 
                 (120 nm) 
                 (1:0.5, 60 nm) 
                 (15 nm) 
                   
                 (30 nm) 
                 (20 nm) 
                 (1 nm) 
                 (1:0.1, 25 nm) 
                 (70 nm) 
               
               
                 Light-emitting 
                 APC\ITO 
                 DBT3P-II:MoO x   
                 BPAFLP 
                 ** 
                 2mDBTBPDBq-II 
                 Bphen 
                 LiF 
                 Ag:Mg 
                 ITO 
               
               
                 element 13(G) 
                 (110 nm) 
                 (1:0.5, 25 nm) 
                 (15 nm) 
                   
                 (15 nm) 
                 (15 nm) 
                 (1 nm) 
                 (1:0.1, 25 nm) 
                 (70 nm) 
               
               
                 Light-emitting 
                 APC\ITO 
                 PCPPn:MoO x   
                 PCPPn 
                 *** 
                 cgDBCzPA 
                 NBphen 
                 LiF 
                 Ag:Mg 
                 ITO 
               
               
                 element 14(B) 
                 (85 nm) 
                 (1:0.5, 37.5 nm) 
                 (15 nm) 
                   
                 (5 nm) 
                 (15 nm) 
                 (1 nm) 
                 (1:0.1, 25 nm) 
                 (70 nm) 
               
               
                 Comparative 
                 APC\ITO 
                 DBT3P-II:MoO x   
                 BPAFLP 
                 **** 
                 2mDBTBPDBq-II 
                 Bphen 
                 LiF 
                 Ag:Mg 
                 ITO 
               
               
                 light-emitting 
                 (110 nm) 
                 (1:0.5, 70 nm) 
                 (15 nm) 
                   
                 (15 nm) 
                 (15 nm) 
                 (1 nm) 
                 (1:0.1, 25 nm) 
                 (70 nm) 
               
               
                 element 15(R) 
               
               
                 Comparative 
                 APC\ITO 
                 PCPPn:MoO x   
                 PCPPn 
                 ***** 
                 cgDBCzPA 
                 NBphen 
                 LiF 
                 Ag:Mg 
                 ITO 
               
               
                 light-emitting 
                 (85 nm) 
                 (1:0.5, 37.5 nm) 
                 (15 nm) 
                   
                 (5 nm) 
                 (15 nm) 
                 (1 nm) 
                 (1:0.1, 25 nm) 
                 (70 nm) 
               
               
                 element 16(B) 
               
               
                   
               
               
                 * 2mDBTBPDBq-IIPCBBiF:[Ir(dmdppr-P) 2 (dibm)] (0.7:0.3:0.04 (20 nm)\0.8:0.2:0.04 (20 nm)) 
               
               
                 ** 2mDBTBPDBq-II:PCBBiF:[Ir(tBuppm) 3 ] (0.7:0.3:0.06 (20 nm)\0.8:0.2:0.06 (20 nm)) 
               
               
                 *** cgDBCzPA:1,6BnfAPrn-03 (1:0.03 (25 nm)) 
               
               
                 **** 2mDBTBPDBq-II:PCBBiF:[Ir(dmdppr-dmp) 2 (dpm)] (0.7:0.3:0.06 (20 nm)\0.8:0.2:0.06 (20 nm)) 
               
               
                 ***** cgDBCzPA:1,6mMemFLPAPrn (1:0.03 (25 nm)) 
               
            
           
         
       
     
                                                                               
&lt;&lt;Fabrication of Light-Emitting Elements&gt;&gt;
 
     Light-emitting elements described in this example each included, as illustrated in  FIG. 30 , the first electrode  1901  over the substrate  1900 , the EL layer  1902  over the first electrode  1901 , and the second electrode  1903  over the EL layer  1902 . In the EL layer  1902 , the hole-injection layer  1911 , the hole-transport layer  1912 , the light-emitting layer  1913 , the electron-transport layer  1914 , and the electron-injection layer  1915  are stacked in this order from the first electrode  1901  side. Note that a light-emitting element  12  and a comparative light-emitting element  15  described in this example were light-emitting elements that mainly emit red light and also referred to as a light-emitting element  12 (R) and a comparative light-emitting element  15 (R), respectively. A light-emitting element  13  was a light-emitting element that mainly emits green light and also referred to as a light-emitting element  13 (G). A light-emitting element  14  and a comparative light-emitting element  16  were light-emitting elements that mainly emit blue light and also referred to as a light-emitting element  14 (B) and a comparative light-emitting element  16 (B), respectively. 
     The light-emitting elements described in this example had element structures different from those of the light-emitting elements described in Examples 1 to 3. Meanwhile, functional layers included in the light-emitting elements can be formed in a manner similar to that described in Example 1; thus, Example 1 is referred to and the description is omitted in this example. 
     &lt;&lt;Operation Characteristics of Light-Emitting Elements&gt;&gt; 
     Operation characteristics of the formed light-emitting elements were measured. Note that the measurement was performed at room temperature (in an atmosphere kept at 25° C.). The results are shown in  FIG. 38  to  FIG. 41 . 
     Table 11 shows initial values of main characteristics of the light-emitting elements at around 1000 cd/m 2 . 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 11 
               
               
                   
                   
               
               
                   
                   
                   
                 Current 
                   
                   
                 Current 
                 Power 
                 External 
               
               
                   
                 Voltage 
                 Current 
                 density 
                 Chromaticity 
                 Luminance 
                 efficiency 
                 efficiency 
                 quantum 
               
               
                   
                 (V) 
                 (mA) 
                 (mA/cm 2 ) 
                 (x, y) 
                 (cd/m 2 ) 
                 (cd/A) 
                 (lm/W) 
                 efficiency (%) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 Light-emitting 
                 3.2 
                 0.10 
                 2.4 
                 (0.711, 0.289) 
                 900 
                 38 
                 37 
                 44 
               
               
                 element 12(R) 
               
               
                 Light-emitting 
                 2.7 
                 0.04 
                 1.1 
                 (0.183, 0.786) 
                 1100 
                 99 
                 110 
                 24 
               
               
                 element 13(G) 
               
               
                 Light-emitting 
                 3.3 
                 1.20 
                 29 
                 (0.141, 0.044) 
                 1100 
                 3.6 
                 3.5 
                 6.9 
               
               
                 element 14(B) 
               
               
                 Comparative 
                 2.9 
                 0.04 
                 0.95 
                 (0.670, 0.331) 
                 840 
                 88 
                 96 
                 48 
               
               
                 light-emitting 
               
               
                 element 15(R) 
               
               
                 Comparative 
                 3.2 
                 0.70 
                 17 
                 (0.138, 0.072) 
                 1000 
                 5.8 
                 5.8 
                 8.7 
               
               
                 light-emitting 
               
               
                 element 16(B) 
               
               
                   
               
            
           
         
       
     
       FIG. 42  shows emission spectra when current at a current density of 2.5 mA/cm 2  was applied to the light-emitting elements. The emission spectra were measured with a multi-channel spectrometer (PMA-12 produced by Hamamatsu Photonics K.K.). As shown in  FIG. 42 , the emission spectrum of the light-emitting element  12  which emits red light has a peak around 635 nm, the emission spectrum of the light-emitting element  13  which emits green light has a peak around 525 nm, and the emission spectrum of the light-emitting element  14  which emits blue light has a peak at around 462 nm. The spectrum shapes were narrowed. Furthermore, the emission spectrum of the comparative light-emitting element  15  has a peak at around 612 nm, and the emission spectrum of the comparative light-emitting element  16  has a peak at around 467 nm. 
     Here, three types of top-emission panels (a panel  1 , a panel  2 , and a panel  3 ) each of which was formed by combination of the light-emitting elements listed in Table 11 were assumed. Table 12 shows the simulation results obtained when a white color at D65 and 300 cd/m 2  is assumed to be displayed entirely under the following conditions: an aperture ratio is 15% (5% for each of the R, G, and B pixels) and attenuation of light by a circular polarizing plate or the like is 60%. 
     
       
         
           
               
               
             
               
                   
                 TABLE 12 
               
             
            
               
                   
                   
               
               
                   
                 Structure 
               
            
           
           
               
               
               
               
            
               
                   
                 Panel 1 
                 Panel 2 
                 Panel 3 
               
               
                   
                 R: Light-emitting 
                 R: Comparative light-emitting 
                 R: Light-emitting 
               
               
                   
                 element 12(R) 
                 element 15(R) 
                 element 12(R) 
               
               
                   
                 G: Light-emitting 
                 G: Light-emitting 
                 G: Light-emitting 
               
               
                   
                 element 13(G) 
                 element 13(G) 
                 element 13(G) 
               
               
                   
                 B: Light-emitting 
                 B: Light-emitting 
                 B: Comparative light-emitting 
               
               
                   
                 element 14(B) 
                 element 14(B) 
                 element 16(B) 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 x 
                 y 
                 x 
                 y 
                 x 
                 y 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Chromaticity 
                 R 
                 0.713 
                 0.287 
                 0.670 
                 0.330 
                 0.713 
                 0.287 
               
               
                   
                 G 
                 0.182 
                 0.786 
                 0.182 
                 0.786 
                 0.182 
                 0.786 
               
               
                   
                 B 
                 0.141 
                 0.045 
                 0.141 
                 0.045 
                 0.138 
                 0.072 
               
            
           
           
               
               
               
               
            
               
                 BT.2020 area ratio 
                 101 
                 83 
                 89 
               
               
                 (CIE (u′, v′)) (%) 
               
            
           
           
               
               
               
               
               
            
               
                 Luminance of 
                 R 
                 73 
                 92 
                 74 
               
               
                 panel (cd/m 2 ) 
                 G 
                 209 
                 191 
                 192 
               
               
                   
                 B 
                 18 
                 18 
                 29 
               
               
                 Luminance in 
                 R 
                 3671 
                 4586 
                 3720 
               
               
                 pixel (cd/m 2 ) 
                 G 
                 10450 
                 9533 
                 9834 
               
               
                   
                 B 
                 879 
                 881 
                 1446 
               
               
                 Voltage (V) 
                 R 
                 4.0 
                 3.5 
                 4.0 
               
               
                   
                 G 
                 3.4 
                 3.4 
                 3.4 
               
               
                   
                 B 
                 3.2 
                 3.2 
                 3.2 
               
               
                 Current 
                 R 
                 36.5 
                 86.4 
                 36.5 
               
               
                 efficiency 
                 G 
                 95.3 
                 95.6 
                 95.5 
               
               
                 (cd/A) 
                 B 
                 3.7 
                 3.7 
                 5.8 
               
            
           
           
               
               
               
               
            
               
                 Power consumption 
                 7.7 
                 6.5 
                 7.8 
               
               
                 (mW/cm 2 ) 
               
               
                   
               
            
           
         
       
     
     As shown in Table 12, the BT.2020 area ratio of the panel  1  formed by the combination of the light-emitting elements  12 (R),  13 (G), and  14 (B) is 101% when being calculated from the chromaticities of the light-emitting elements on the CIE1976 chromaticity coordinates (u′,v′ chromaticity coordinates), which were obtained from the chromaticities in Table 11. The BT.2020 area ratio of the panel  2  formed by the combination of the comparative light-emitting element  15 (R) and the light-emitting elements  13 (G) and  14 (B) is 83%, and the BT.2020 area ratio of the panel  3  formed by the combination of the light-emitting elements  12 (R) and  13 (G) and the comparative light-emitting element  16 (B) is 89%.  FIG. 55  is a chromaticity diagram showing the chromaticities of the light-emitting elements  12 (R),  13 (G), and  14 (B) and the comparative light-emitting elements  15 (R) and  16 (B) on the CIE1976 chromaticity coordinates (u′,v′ chromaticity coordinates). 
     According to the above results, the use of the light-emitting elements described in this example can offer extremely wide-range color reproducibility. 
     Reliability tests were performed on the light-emitting elements.  FIG. 43  shows results of the reliability tests. In  FIG. 43 , the vertical axis represents normalized luminance (%) with an initial luminance of 100%, and the horizontal axis represents driving time (h) of the elements. Note that in the reliability tests, the light-emitting elements were driven under the conditions where the initial luminance was set to 300 cd/m 2  and the current density was constant. 
     The results in  FIG. 43  indicate that the reliability of the light-emitting element  12 (R) is as high as that of the comparative light-emitting element  15 (R) even though the light-emitting element  12 (R) has higher current density than the comparative light-emitting element  15 (R). The results also indicate that the light-emitting element  14 (B) has higher reliability than the comparative light-emitting element  16 (B). 
     Example 5 
     In this example, an element structure and properties of a light-emitting element used in the light-emitting device of one embodiment of the present invention will be described. Note that  FIG. 30  illustrates an element structure of light-emitting elements described in this example, and Table 13 shows specific structures. Chemical formulae of materials used in this example are shown below. 
     
       
         
           
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 13 
               
               
                   
                   
               
               
                   
                 First 
                 Hole-injection 
                 Hole-transport 
                 Light-emitting 
                 Electron-transport 
                 Electron-injection 
                 Second 
               
               
                   
                 electrode 
                 layer 
                 layer 
                 layer 
                 layer 
                 layer 
                 electrode 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 Light-emitting 
                 ITO 
                 DBT3P-II:MoO x   
                 BPAFLP 
                 * 
                 2mDBTBPDBq-II 
                 NBphen 
                 LiF 
                 Al 
               
               
                 element 17(R) 
                 (70 nm) 
                 (1:0.5, 75 nm) 
                 (20 nm) 
                   
                 (30 nm) 
                 (15 nm) 
                 (1 nm) 
                 (200 nm) 
               
               
                 Light-emitting 
                   
                   
                   
                 ** 
               
               
                 element 18(R) 
               
               
                   
               
               
                 * 2mDBTBPDBq-II:PCBBiF:[Ir(dmdppr-dmp)) 2 (dpm)] (0.7:0.3:0.06 (20 nm)\ 0.8:0.2:0.06 (20 nm)) 
               
               
                 ** 2mDBTBPDBq-II:PCBBiF:[Ir(dmdppr-P) 2 (dibm)] (0.7:0.3:0.06 (20 nm)\ 0.8:0.2:0.06 (20 nm)) 
               
            
           
         
       
     
                         
&lt;&lt;Fabrication of Light-Emitting Elements&gt;&gt;
 
     Light-emitting elements described in this example each included, as illustrated in  FIG. 30 , the first electrode  1901  over the substrate  1900 , the EL layer  1902  over the first electrode  1901 , and the second electrode  1903  over the EL layer  1902 . In the EL layer  1902 , the hole-injection layer  1911 , the hole-transport layer  1912 , the light-emitting layer  1913 , the electron-transport layer  1914 , and the electron-injection layer  1915  are stacked in this order from the first electrode  1901  side. Note that a light-emitting element  17  and a comparative light-emitting element  18  in this example were each a light-emitting element emitting mainly red light. 
     The light-emitting elements described in this example had element structures different from those of the light-emitting elements described in Examples 1 to 4. Meanwhile, functional layers included in the light-emitting elements can be formed in a manner similar to that described in Example 1; thus, Example 1 is referred to and the description is omitted in this example. 
     &lt;&lt;Operation Characteristics of Light-Emitting Elements&gt;&gt; 
     Operation characteristics of the formed light-emitting elements were measured. Note that the measurement was performed at room temperature (in an atmosphere kept at 25° C.). Table 14 shows initial values of main characteristics of the light-emitting elements at around 1000 cd/m 2 . 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 14 
               
               
                   
                   
               
               
                   
                   
                   
                 Current 
                   
                   
                 Current 
                 Power 
                 External 
               
               
                   
                 Voltage 
                 Current 
                 density 
                 Chromaticity 
                 Luminance 
                 efficiency 
                 efficiency 
                 quantum 
               
               
                   
                 (V) 
                 (mA) 
                 (mA/cm 2 ) 
                 (x, y) 
                 (cd/m 2 ) 
                 (cd/A) 
                 (lm/W) 
                 efficiency (%) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 Light-emitting 
                 3.6 
                 0.23 
                 5.8 
                 (0.709, 0.290) 
                 940 
                 16.2 
                 14 
                 27.4 
               
               
                 element 17(R) 
               
               
                 Comparative 
                 3.3 
                 0.13 
                 3.1 
                 (0.669, 0.331) 
                 1100 
                 34.2 
                 33 
                 29.9 
               
               
                 light-emitting 
               
               
                 element 18(R) 
               
               
                   
               
            
           
         
       
     
       FIG. 44  shows emission spectra when current at a current density of 2.5 mA/cm 2  was applied to the light-emitting elements. The emission spectra were measured with a multi-channel spectrometer (PMA-12 manufactured by Hamamatsu Photonics K.K.). The emission spectrum of a light-emitting element  17 (R) has a peak wavelength at around 642 nm, and the full width at half maximum (FWHM) is 62 nm. The emission spectrum of a comparative light-emitting element  18 (R) has a peak wavelength at around 612 nm, and the full width at half maximum (FWHM) is 62 nm. The light-emitting element  17 (R) and the comparative light-emitting element  18 (R) have similar spectrum shapes. 
       FIG. 45  shows the CIE1931 chromaticity coordinates (x,y chromaticity coordinates) of the light-emitting element  17 (R) and the comparative light-emitting element  18 (R).  FIG. 45  indicates that the light-emitting element  17 (R) meets the chromaticity of red in the BT.2020 standard. 
       FIG. 46  shows the relationships between external quantum efficiency and current density of the light-emitting element  17 (R) and the comparative light-emitting element  18 (R). The elements show similar results. 
     Driving tests were conducted on the light-emitting element  17 (R) and the comparative light-emitting element  18 (R) with a driving current of 50 mA/cm 2 .  FIG. 47  shows the results obtained when the tests were conducted at room temperature (25° C.) and  FIG. 48  shows the results obtained when the tests were conducted at a high temperature (85° C.). The results indicate that the light-emitting element  17 (R) can be driven for 1200 hours at room temperature (25° C.) until the normalized luminance is reduced to 50% while the comparative light-emitting element  18 (R) can be driven for 500 hours, which reveals that the lifetime of the light-emitting element  17 (R) is approximately 2.4 times as long as that of the comparative light-emitting element  18 (R). The results also indicate that the light-emitting element  17 (R) can be driven for 210 hours at a high temperature (85° C.) until the normalized luminance is reduced to 50% while the comparative light-emitting element  18 (R) can be driven for 75 hours, which reveals that the lifetime of the light-emitting element  17 (R) is approximately 3 times as long as that of the comparative light-emitting element  18 (R). Thus, it is found that the light-emitting element  17 (R) has smaller temperature dependence of lifetime than the comparative light-emitting element  18 (R). 
     In addition, the comparison result of the driving time of the light-emitting element  17 (R) until the normalized luminance is reduced to 50% in  FIG. 47  and  FIG. 48  indicates that the lifetime when driven at a high temperature (85° C.) is only approximately ⅕ shorter than the lifetime when driven at room temperature (25° C.). This means that the light-emitting element  17 (R) has favorable heat resistance and has a long lifetime even at high temperatures. 
       FIG. 49  shows the results of preservation test at high temperatures for the light-emitting element  17 (R). As apparent from  FIG. 49 , even when the light-emitting element  17 (R) is preserved at a high temperature (85° C.) for 200 hours, the luminance change is small (maximum of 1.5%) and the driving voltage change is small (maximum of 0.05%). 
     Example 6 
     In this example, an element structure and properties of a light-emitting element used in the light-emitting device of one embodiment of the present invention will be described. Note that  FIG. 30  illustrates an element structure of light-emitting elements described in this example, and Table 15 shows specific structures. Chemical formulae of materials used in this example are shown below. 
     
       
         
           
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 15 
               
               
                   
                   
               
               
                   
                 First 
                 Hole-injection 
                 Hole-transport 
                 Light-emitting 
                 Electron-transport 
                 Electron-injection 
                 Second 
               
               
                   
                 electrode 
                 layer 
                 layer 
                 layer 
                 layer 
                 layer 
                 electrode 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 Light-emitting 
                 ITO 
                 PCPPn:MoO x   
                 PCPPn 
                 * 
                 cgDBCzPA 
                 NBphen 
                 LiF 
                 Al 
               
               
                 element 19(B) 
                 (70 nm) 
                 (42, 10 nm) 
                 (30 nm) 
                   
                 (15 nm) 
                 (10 nm) 
                 (1 nm) 
                 (200 nm) 
               
               
                 Light-emitting 
                   
                   
                 PCPPn 
                 ** 
               
               
                 element 20(B) 
                   
                   
                 (25 nm) 
               
               
                   
               
               
                 * cgDBCzPA:1,6BnfAPrn-03 (1:0.03 (25 nm)) 
               
               
                 ** cgDBCzPA:1,6mMemFLPAPrn (1:0.03 (25 nm)) 
               
            
           
         
       
     
                                           
&lt;&lt;Fabrication of Light-Emitting Elements&gt;&gt;
 
     Light-emitting elements described in this example each included, as illustrated in  FIG. 30 , the first electrode  1901  over the substrate  1900 , the EL layer  1902  over the first electrode  1901 , and the second electrode  1903  over the EL layer  1902 . In the EL layer  1902 , the hole-injection layer  1911 , the hole-transport layer  1912 , the light-emitting layer  1913 , the electron-transport layer  1914 , and the electron-injection layer  1915  are stacked in this order from the first electrode  1901  side. Note that a light-emitting element  19  and a comparative light-emitting element  20  in this example were each a light-emitting element emitting mainly blue light. 
     The light-emitting elements described in this example had element structures different from those of the light-emitting elements described in Examples 1 to 5. Meanwhile, functional layers included in the light-emitting elements can be formed in a manner similar to that described in Example 1; thus, Example 1 is referred to and the description is omitted in this example. 
     &lt;&lt;Operation Characteristics of Light-Emitting Elements&gt;&gt; 
     Operation characteristics of the formed light-emitting elements were measured. Note that the measurement was performed at room temperature (in an atmosphere kept at 25° C.). Table 16 shows initial values of main characteristics of the light-emitting elements at around 1000 cd/m 2 . 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 16 
               
               
                   
                   
               
               
                   
                   
                   
                 Current 
                   
                   
                 Current 
                 Power 
                 External 
               
               
                   
                 Voltage 
                 Current 
                 density 
                 Chromaticity 
                 Luminance 
                 efficiency 
                 efficiency 
                 quantum 
               
               
                   
                 (V) 
                 (mA) 
                 (mA/cm 2 ) 
                 (x, y) 
                 (cd/m 2 ) 
                 (cd/A) 
                 (lm/W) 
                 efficiency (%) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 Light-emitting 
                 3.1 
                 0.36 
                 9.0 
                 (0.140, 0.115) 
                 940 
                 10.4 
                 11 
                 10.8 
               
               
                 element 19(B) 
               
               
                 Comparative 
                 3.1 
                 0.28 
                 7.1 
                 (0.137, 0.177) 
                 1100 
                 15.7 
                 16 
                 12.7 
               
               
                 light-emitting 
               
               
                 element 20(B) 
               
               
                   
               
            
           
         
       
     
       FIG. 50  shows emission spectra when current at a current density of 12.5 mA/cm 2  was applied to the light-emitting elements. The emission spectra were measured with a multi-channel spectrometer (PMA-12 manufactured by Hamamatsu Photonics K.K.). The emission spectrum of a light-emitting element  19 (B) has a peak wavelength at around 458 nm, and the emission spectrum of a comparative light-emitting element  20 (B) has a peak wavelength at around 468 nm. The results show that blue light emitted from the light-emitting element  19 (B) is deeper than that emitted from the comparative light-emitting element  20 (B). 
       FIG. 51  shows the relationships between external quantum efficiency and luminance of the light-emitting element  19 (B) and the comparative light-emitting element  20 (B). The results show that the light-emitting element  19 (B) has lower external quantum efficiency than the comparative light-emitting element  20 (B). This is because the fluorescence quantum yield of the light-emitting element  19 (B) (77%) is lower than the fluorescence quantum yield of the comparative light-emitting element  20 (B) (90%) by approximately 10%. 
     Driving tests were conducted on the light-emitting element  19 (B) and the comparative light-emitting element  20 (B) with a driving current of 50 mA/cm 2 .  FIG. 52  shows the results obtained when the tests were conducted at room temperature (25° C.) and  FIG. 53  shows the results obtained when the tests were conducted at a high temperature (85° C.). The results indicate that the light-emitting element  19 (B) can be driven for approximately 500 hours at room temperature (25° C.) until the normalized luminance is reduced to 80% while the comparative light-emitting element  20 (B) can drive for approximately 200 hours, which reveals that the lifetime of the light-emitting element  19 (B) is approximately 2.5 times as long as that of the comparative light-emitting element  20 (B). The results also indicate that the light-emitting element  19 (B) can be driven for 82 hours at a high temperature (85° C.) until the normalized luminance is reduced to 80% while the comparative light-emitting element  20 (B) can be driven for 29 hours, which reveals that the lifetime of the light-emitting element  19 (B) is approximately 2.8 times as long as that of the comparative light-emitting element  20 (B). Thus, it is found that the light-emitting element  19 (B) has smaller temperature dependence of lifetime than the comparative light-emitting element  20 (B). 
     In addition, the comparison result of the driving time of the light-emitting element  19 (B) until the normalized luminance is reduced to 80% in  FIG. 52  and  FIG. 53  indicates that the lifetime when driven at a high temperature (85° C.) is only approximately ⅙ shorter than the lifetime when driven at room temperature (25° C.). This means that the light-emitting element  19 (B) has favorable heat resistance and has a long lifetime even at high temperatures. 
       FIG. 54  shows the results of preservation test at high temperatures for the light-emitting element  19 (B). As apparent from  FIG. 54 , even when the light-emitting element  19 (B) is preserved at a high temperature (85° C.) for 250 hours, the luminance change and the driving voltage change are small (maximum of 0.8%). 
     REFERENCE NUMERALS 
       1 : first electrode,  102 : second electrode,  103 : EL layer,  103 R: EL layer,  103 G: EL layer,  103 B: EL layer,  104 R: color filter,  104 G: color filter,  104 B: color filter,  105 R: first light-emitting element,  105 G: second light-emitting element,  105 B: third light-emitting element,  106 R: red light,  106 G: green light,  106 B: blue light,  201 : first electrode,  202 : second electrode,  203 : EL layer,  203   a : EL layer,  203   b : EL layer,  204 : charge generation layer,  211 : hole-injection layer,  211   a : hole-injection layer,  211   b : hole-injection layer,  212 : hole-transport layer,  212   a : hole-transport layer,  212   b : hole-transport layer,  213 : light-emitting layer,  213   a : light-emitting layer,  213   b : light-emitting layer,  214 : electron-transport layer,  214   a : electron-transport layer,  214   b : electron-transport layer,  215 : electron-injection layer,  215   a : electron-injection layer,  215   b : electron-injection layer,  301 : first substrate,  302 : transistor (FET),  303 : light-emitting element,  303 R: light-emitting element,  303 G: light-emitting element,  303 B: light-emitting element,  303 W: light-emitting element,  304 : EL layer,  305 : second substrate,  306 R: color filter,  306 G: color filter,  306 B: color filter,  307 : first electrode,  308 : second electrode,  309 : black layer (black matrix),  401 : first substrate,  402 : pixel portion,  403 : driver circuit portion,  404   a : driver circuit portion,  404   b : driver circuit portion,  405 : sealant,  406 : second substrate,  407 : lead wiring,  408 : flexible printed circuit (FPC),  409 : FET,  410 : FET,  411 : FET (switching FET),  412 : FET (current control FET),  413 : first electrode,  414 : insulator,  415 : EL layer,  416 : second electrode,  417 : light-emitting element,  418 : space,  900 : substrate,  901 : first electrode,  902   a : first EL layer,  902   b : second EL layer,  903 : second electrode,  904 : charge generation layer,  905 : substrate,  906 : color filter,  911   a : first hole-injection layer,  911   b : second hole-injection layer,  912   a : first hole-transport layer,  912   b : second hole-transport layer,  913   a : light-emitting layer (A),  913 ( b   1 ): light-emitting layer (B 1 ),  913 ( b   2 ): light-emitting layer (B 2 ),  914   a : first electron-transport layer,  914   b : second electron-transport layer,  915   a : first electron-injection layer,  915   b : second electron-injection layer,  1900 : substrate,  1901 : first electrode,  1902 : EL layer,  1903 : second electrode,  1911 : hole-injection layer,  1912 : hole-transport layer,  1913 : light-emitting layer,  1914 : electron-transport layer,  1915 : electron-injection layer,  2000 : touch panel,  2501 : display panel,  2502 R: pixel,  2502   t : transistor,  2503   c : capacitor,  2503   g : scan line driver circuit,  2503   t : transistor,  2509 : FPC,  2510 : substrate,  2511 : wiring,  2519 : terminal,  2521 : insulating layer,  2528 : insulator,  2550 R: light-emitting element,  2560 : sealing layer,  2567 BM: light-blocking layer,  2567   p : anti-reflection layer,  2567 R: coloring layer,  2570 : substrate,  2590 : substrate,  2591 : electrode,  2592 : electrode,  2593 : insulating layer,  2594 : wiring,  2595 : touch sensor,  2597 : adhesive layer,  2598 : wiring,  2599 : terminal,  2601 : pulse voltage output circuit,  2602 : current sensing circuit,  2603 : capacitor,  2611 : transistor,  2612 : transistor,  2613 : transistor,  2621 : electrode,  2622 : electrode,  3000 : display device,  3001 : circuit (G),  3002 : circuit (S),  3003 : display portion,  3004 : pixel,  3005 : conductive film,  3007 : opening,  3010 : liquid crystal element,  3011 : light-emitting element,  3015 : transistor,  3016 : transistor,  3017 : transistor,  3018 : terminal portion,  3019 : terminal portion,  3021 : substrate,  3022 : substrate,  3023 : light-emitting element,  3024 : liquid crystal element,  3025 : insulating layer,  3028 : coloring layer,  3029 : adhesive layer,  3030 : conductive layer,  3031 : EL layer,  3032 : conductive layer,  3033 : opening,  3034 : coloring layer,  3035 : light-blocking layer,  3036 : structure,  3037 : conductive layer,  3038 : liquid crystal,  3039 : conductive layer,  3040 : alignment film,  3041 : alignment film,  3042 : adhesive layer,  3043 : conductive layer,  3044 : FPC,  3045 : connection layer,  3046 : insulating layer,  3047 : connection portion,  3048 : connector,  4000 : lighting device,  4001 : substrate,  4002 : light-emitting element,  4003 : substrate,  4004 : electrode,  4005 : EL layer,  4006 : electrode,  4007 : electrode,  4008 : electrode,  4009 : auxiliary wiring,  4010 : insulating layer,  4011 : sealing substrate,  4012 : sealant,  4013 : desiccant,  4015 : diffusion plate,  4100 : lighting device,  4200 : lighting device,  4201 : substrate,  4202 : light-emitting element,  4204 : electrode,  4205 : EL layer,  4206 : electrode,  4207 : electrode,  4208 : electrode,  4209 : auxiliary wiring,  4210 : insulating layer,  4211 : sealing substrate,  4212 : sealant,  4213 : barrier film,  4214 : planarization film,  4215 : diffusion plate,  4300 : lighting device,  5101 : light,  5102 : wheel,  5103 : door,  5104 : display portion,  5105 : steering wheel,  5106 : gear lever,  5107 : seat,  5108 : inner rearview mirror,  7100 : television device,  7101 : housing,  7103 : display portion,  7105 : stand,  7107 : display portion,  7109 : operation key,  7110 : remote controller,  7201 : main body,  7202 : housing,  7203 : display portion,  7204 : keyboard,  7205 : external connection port,  7206 : pointing device,  7302 : housing,  7304 : display portion,  7305 : icon,  7306 : icon,  7311 : operation button,  7312 : operation button,  7313 : connection terminal,  7321 : band,  7322 : clasp,  7400 : mobile phone,  7401 : housing,  7402 : display portion,  7403 : operation button,  7404 : external connection portion,  7405 : speaker,  7406 : microphone,  7407 : camera,  7500 ( 1 ): housing,  7500 ( 2 ): housing,  7501 ( 1 ): first screen,  7501 ( 2 ): first screen,  7502 ( 1 ): second screen,  7502 ( 2 ): second screen,  8001 : ceiling light,  8002 : foot light,  8003 : sheet-like lighting,  8004 : lighting device,  9310 : portable information terminal,  9311 : display portion,  9312 : display region,  9313 : hinge, and  9315 : housing. 
     This application is based on Japanese Patent Application Serial No. 2016-101783 filed with Japan Patent Office on May 20, 2016, Japanese Patent Application Serial No. 2016-178920 filed with Japan Patent Office on Sep. 13, 2016, and Japanese Patent Application Serial No. 2016-231618 filed with Japan Patent Office on Nov. 29, 2016, the entire contents of which are hereby incorporated by reference.