Patent Publication Number: US-2018040851-A1

Title: Display device and method for manufacturing the same

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2016-153501, filed on Aug. 4, 2016, the entire contents of which are incorporated herein by reference. 
     FIELD 
     An embodiment of the present invention relates to a display device and a method for manufacturing the same. 
     BACKGROUND 
     As display devices usable for electric appliances and electronic devices, a liquid crystal display device using an electro-optical effect of a liquid crystal material and an organic EL (electroluminescence) display device including an organic electroluminescence (EL) element have been developed. Such a display device includes a display screen formed of a plurality of pixels provided on a substrate. Each of the plurality of pixels of the display device includes a liquid crystal element, an organic electroluminescence element or the like as a display element. In the display device, such pixels arrayed in a display region are driven by a pixel circuit and a driving circuit each including a transistor, and thus a signal is input and a moving image or a still image is displayed. 
     It is known that in the case where an organic EL element is used as a display element, an organic EL layer is deteriorated by moisture. When the display device is driven by use of such a deteriorated organic EL layer, the luminance may be decreased or a display failure may occur. In order to prevent the organic EL layer from being contaminated with moisture, a sealing film is provided. The sealing film may be formed of a combination of an organic insulating layer and an inorganic insulating layer acting as a barrier layer. 
     Japanese Laid-Open Patent Publication No. 2010-272270 discloses a display device including an organic insulating layer containing a material that is colored when being reacted with moisture. Such a material is contained in order to detect permeation of moisture into the organic insulating layer. 
     Japanese Laid-Open Patent Publication No. 2011-138748 discloses a display device including at least one organic insulating layer and at least one barrier film alternately provided in a stacking manner. Such a structure is provided in order to improve the sealing performance against moisture. 
     SUMMARY 
     An embodiment according to the present invention provides a display device including a first inorganic insulating layer covering a display region; a first organic insulating layer on the first inorganic insulating layer; a second inorganic insulating layer on the first organic insulating layer; a second organic insulating layer on the second inorganic insulating layer; and a third inorganic insulating layer on the second organic insulating layer. The second organic insulating layer contains a compound reactive with moisture; and the first organic insulating layer is thicker than the second organic insulating layer. 
    
    
     
       BRIEF EXPLANATION OF THE DRAWINGS 
         FIG. 1A  and  FIG. 1B  are each a plan view showing a structure of a display device in an embodiment according to the present invention, and  FIG. 10  is a cross-sectional view showing a structure of the display device in an embodiment according to the present invention; 
         FIG. 2A ,  FIG. 2B ,  FIG. 2C  and  FIG. 2D  are each a cross-sectional view showing a structure of the display device in an embodiment according to the present invention; 
         FIG. 3  is a cross-sectional view showing a structure of the display device in an embodiment according to the present invention; 
         FIG. 4  is a cross-sectional view showing a structure of the display device in an embodiment according to the present invention; 
         FIG. 5  is a cross-sectional view showing a structure of the display device in an embodiment according to the present invention; 
         FIG. 6  is a cross-sectional view showing a structure of the display device in an embodiment according to the present invention; 
         FIG. 7  is a cross-sectional view showing a structure of the display device in an embodiment according to the present invention; 
         FIG. 8  is a cross-sectional view showing a structure of the display device in an embodiment according to the present invention; 
         FIG. 9  is a cross-sectional view showing a method for manufacturing the display device in an embodiment according to the present invention; 
         FIG. 10  is a cross-sectional view showing the method for manufacturing the display device in an embodiment according to the present invention; 
         FIG. 11  is a cross-sectional view showing the method for manufacturing the display device in an embodiment according to the present invention; and 
         FIG. 12  is a cross-sectional view showing the method for manufacturing the display device in an embodiment according to the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments according to the present invention will be described with reference to the drawings. The present invention may be carried out in any of various forms and should not be construed as being limited to any of the following embodiments. In the drawings, components may be shown schematically regarding the width, thickness, shape and the like, instead of being shown in accordance with the actual sizes, for the sake of clearer illustration. The drawings are merely examples and do not limit the interpretations of the present invention in any way. In the specification and the drawings, components that have substantially the same functions as those described before with reference to a previous drawing(s) bear the identical reference signs thereto (or identical numerals with “a”, “b” or the like provided after the numerals), and detailed descriptions thereof may be omitted. The words “first”, “second” or the like provided for components are used merely to distinguish the components from each other, and do not have any further meaning unless otherwise specified. 
     In the specification and the claims, an expression that a component or a region is “on” another component or region encompasses a case where such a component or region is in direct contact with the another component or region and also a case where such a component is above or below the another component or region, namely, a case where still another component or region is provided between such a component or region and the another component or region, unless otherwise specified. In the following description, the terms “above”, “up” and the like refer to the side on which a second substrate is provided with respect to a first substrate, and the terms “below”, “down” and the like refer to the opposite side. 
     In this specification, the first substrate at least includes one main surface that is planar. On the one main surface, layers including a semiconductor layer and a conductive layer, and components including a transistor and a display element, are provided. A description provided below regarding a cross-section is made with respect to the one main surface of the first substrate. The terms “up”, “upper layer”, “above” and “upper surface” are used with respect to the one main surface of the first substrate. 
     A display device including an organic EL element having the above-described moisture detection function may not provide a sufficient level of sealing performance. For an organic insulating layer having the moisture detection function, it is difficult to control the positions of colorants, and thus the moisture detection function may not be provided with a sufficiently high level. 
     An embodiment according to the present invention provided below discloses a display device having both of a function of quickly detecting moisture permeation into any part of a display region covered with a sealing film and a sealing performance of a sufficiently high level to prevent permeation of moisture into a light emitting element. An embodiment according to the present invention discloses a display device having a high reliability. 
     Embodiment 1 
       FIG. 1A  is a plan view of a display device  10 . As shown in  FIG. 1A , the display device  10  includes a substrate  100 , a display region  103  including pixels  102 , a peripheral region  104  provided along a periphery of the display region  103 , a driving circuit  106  having a function of a source driver, a driving circuit  107  having a function of a gate driver, and a flexible printed circuit board  108 . 
     The display device  10  is operated as follows. A video signal is input to the display device  10  via the flexible printed circuit board  108 , and thus the driving circuit  106  and the driving circuit  107  drive the pixels  102 . As a result, a still image or a moving image is displayed in the display region  103 . 
       FIG. 1B  is an enlarged view of a plan view of a region between A 1  and A 2  in  FIG. 1A  corresponding to the peripheral region  104  of the display device  10 .  FIG. 10  is a cross-sectional view of the display device  10  taken along line A 1 -A 2  in  FIG. 1A .  FIG. 2A ,  FIG. 2B ,  FIG. 2C  and  FIG. 2D  each show a modification of the cross-sectional structure shown in  FIG. 10 . 
     The display device  10  includes a sealing film  161  provided so as to cover the display region  103 . The sealing film  161  is provided on a conductive layer  160  acting as an electrode of a display element (or light emitting element)  130  ( FIG. 3 ) described below. As shown in  FIG. 10 , the sealing film  161  includes an inorganic insulating layer  162 , an organic insulating layer  163 , an inorganic insulating layer  164 , an organic insulating layer  165  and an inorganic insulating layer  169 , which are stacked in this order from the side of the display element  130 . 
     The inorganic insulating layer  162 , the inorganic insulating layer  164  and the inorganic insulating layer  169  are formed of an inorganic insulating material. More specifically, the inorganic insulating layer  162 , the inorganic insulating layer  164  and the inorganic insulating layer  169  may each be formed of at least one selected from aluminum oxide, magnesium oxide, silicon oxide, silicon oxide nitride, silicon nitride oxide, and silicon nitride. The inorganic insulating layer  162 , the inorganic insulating layer  164  and the inorganic insulating layer  169  may each have a thickness of several ten nanometers to several micrometers. The inorganic insulating layer  162 , the inorganic insulating layer  164  and the inorganic insulating layer  169  are formed of any of the above-described materials so as to have a barrier function against moisture. 
     The organic insulating layer  163  may be formed of an organic insulating material such as acrylic resin, polyimide resin, epoxy resin or the like. The organic insulating layer  163  preferably has a thickness of 10 μm or greater and less than 100 μm. The organic insulating layer  163  may be a single layer or may be a stack of a plurality of layers. 
     The organic insulating layer  165  may be formed of any of substantially the same materials as those usable for the organic insulating layer  163 . The organic insulating layer  165  further contains, in the organic material, a compound reactive with moisture or oxygen. A compound reactive with moisture or oxygen is, for example, colored as a result of being reacted with moisture or oxygen. A preferable example of a compound that is colored as a result of being reacted with moisture is a colorant. Examples of colorant that is colored as a result of being reacted with moisture include phenolphthalein, thymolphthalein, sodium carbonate and the like. Examples of compound that is colored as a result of being reacted with oxygen include indigocarmine, methylene blue and the like. For example, phenolphthalein and sodium carbonate, when being contained in the organic insulating layer  165  as the colorants, act as follows. When moisture permeates into the organic insulating layer  165 , the moisture is reacted with sodium carbonate to become alkaline. At this point, phenolphthalein is reacted with hydroxide ion (OH − ) in the moisture to be colored pink. The total content of the compounds is preferably about 3% by weight with respect to the total weight of the organic insulating layer  165 . The organic insulating layer  165  is preferably thinner than the organic insulating layer  163 , and preferably has a thickness of 0.5 μm or greater and less than 10 μm. 
     As a material reactive with moisture, alkaline metal, alkaline earth metal or the like is usable as well as the colorant. 
     As described above, the two organic insulating layers are provided and the upper organic insulating layer contains a colorant, so that the sealing performance is improved and, if moisture permeates, occurrence of such an abnormal state is detected easily. 
     The organic insulating layer  165  is provided as a thin layer, so that the density of the colorant in the organic insulating layer  165  is increased. With such a structure, moisture, if permeating into the sealing film  161 , is detected with a high level of precision, and occurrence of such an abnormal state is detected quickly. The thin organic insulating layer  165  allows the organic insulating layer  163 , which is located below the thin organic insulating layer  165 , to be thicker, which improves the sealing performance. 
     As shown in  FIG. 1B  and  FIG. 10 , it is desirable that in the sealing film  161 , edges of the organic insulating layer  163  and the organic insulating layer  165  are located between an edge of the display region  103  and edges of the inorganic insulating layer  162 , the inorganic insulating layer  164  and the inorganic insulating layer  169 . Alternatively, it is desirable that a region outer to the display region  103  includes a region where the inorganic insulating layer  162  and the inorganic insulating layer  164  are in direct contact with, and stacked on, each other and the inorganic insulating layer  164  and the inorganic insulating layer  169  are in direct contact with, and stacked on, each other (such a region will be referred to as an “inorganic insulating layer stack region”) and that the edge of the organic insulating layer  163  and the edge of the organic insulating layer  165  are located between the display region  103  and the inorganic insulating layer stack region. Namely, it is preferable that the inorganic insulating layer  162  is located below the organic insulating layer  163  and inorganic insulating layer  164  is located above the organic insulating layer  163  and thus the edge of the organic insulating layer  163  is covered with the inorganic insulating layer  164  and, in a region outer to the edge of the organic insulating layer  163 , the inorganic insulating layer  162  and the inorganic insulating layer  164  are in contact with each other. In this manner, the edge of the organic insulating layer  163  is located inner to the edges of the inorganic insulating layer  162  and the inorganic insulating layer  164 , and the organic insulating layer  163  is held between the inorganic insulating layer  162  on the lower side and the inorganic insulating layer  164  on the upper side. With such a structure, the edge of the organic insulating layer  163  is not exposed to an outer surface of the display device  10 . With such a structure, the inorganic insulating layer  162 , the inorganic insulating layer  164  and the inorganic insulating layer  169  are in contact with each other, and thus the sealing performance of the sealing film  161  is improved to enhance the moisture blocking effect. 
     In the sealing film  161 , the edges of the organic insulating layer  163  and the organic insulating layer  165  preferably have a mild tapering shape. With such a shape, the area ratio of the surfaces of the organic insulating layer  163  and the organic insulating layer  165  that are covered with the inorganic insulating layer  164  and the inorganic insulating layer  169  is increased, and thus the moisture blocking effect is enhanced. Among the edge of the organic insulating layer  163  and the edge of the organic insulating layer  165 , either one may be outer to the other (see  FIG. 10  and  FIG. 2A ). 
     For these reasons, the display device  10  having the above-described structure has both of a high level of sealing performance and a function of detecting moisture permeation quickly. 
     The inorganic insulating layer  164  may be as thick as each of the inorganic insulating layer  162  and the inorganic insulating layer  169 , or may be thinner than one of, or both of, the inorganic insulating layer  162  and the inorganic insulating layer  169  as shown in  FIG. 2B . In the case where the inorganic insulating layer  164  is thinner, the production cost is reduced, and the transmittance of light output from the light emitting element is increased. 
     The display device  10  may include a moisture absorption layer  166  and a gas releasing layer  167  on the sealing film  161  as shown in  FIG. 2C  and  FIG. 2D . 
     The moisture absorption layer  166  has a function of absorbing moisture. The moisture absorption layer  166  may be formed of an organic insulating material, an inorganic insulating material, or a composite material of an organic insulating material and an inorganic insulating material. The moisture absorption layer  166  is preferably contain, for example, silicon-containing polymer. Specifically, polysilazane, for example, is usable. The moisture absorption layer  166  prevents moisture from permeating into the inorganic insulating layer  169  and the layers therebelow. 
     As shown in  FIG. 2C  and  FIG. 2D , the moisture absorption layer  166  and the gas releasing layer  167  may be provided on the inorganic insulating layer  169  of the sealing film  161 . 
     The gas releasing layer  167  has a function of releasing gas present in the layers. The gas releasing layer  167  may contain a thermosetting resin or a thermoplastic resin such as acrylic resin, polyimide resin, epoxy resin or the like. 
     In the case where, for example, the moisture absorption layer  166  is formed of polysilazane, polysilazane and moisture are reacted with each other to generate ammonia gas. The gas releasing layer  167  allows the ammonia gas to be released therethrough to the outside. Thus, generation of gas bubbles and delamination of layers at the interfaces, which are caused by generation and stay of the gas, are suppressed. 
     The display device  10  having the above-described structure has a high level of sealing performance and has a function of quickly detecting moisture, if moisture permeates, and also a function of suppressing other defects caused by the permeation of the moisture. Thus, the display device  10  is highly reliable. 
     The structure, method or the like described in embodiment  1  may be appropriately combined with a structure, method or the like shown in any other embodiment. 
     Embodiment 2 
     Hereinafter, a structure of the display device  10  including components other than those described above will be described with reference to the drawings. 
       FIG. 3  is a cross-sectional view of the display device  10 . More specifically,  FIG. 3  shows a cross-section of the peripheral region  104  taken along line A 1 -A 2  in  FIG. 1A , a cross-section of a pixel region including one pixel  102  taken along line B 1 -B 2  in  FIG. 1A , a cross-section of a driving circuit region including the driving circuit  107  taken along line C 1 -C 2  in  FIG. 1A , and a cross-section of a terminal region including the driving circuit  106  taken along line D 1 -D 2  in  FIG. 1A .  FIG. 3  shows the structure of the display device  10  in the case where the sealing film  161  has the structure shown in  FIG. 1C .  FIG. 4  shows the structure of the modification of the display device  10 , in which the sealing film  161  has the structure shown in  FIG. 2A .  FIG. 5  shows the structure of the modification of the display device  10 , in which the sealing film  161  has the structure shown in  FIG. 2B .  FIG. 6  shows the structure of the modification of the display device  10 , in which the sealing film  161  has the structure shown in  FIG. 2C .  FIG. 7  shows the structure of the modification of the display device  10 , in which the sealing film  161  has the structure shown in  FIG. 2D . (Hereinafter, the peripheral region  104  may be referred to as the “peripheral region A 1 -A 2  region”, the pixel region may be referred to as the “pixel region B 1 -B 2 ”, the driving circuit region may be referred to as the “driving circuit region C 1 -C 2 ”, and the terminal region may be referred to as the “terminal region D 1 -D 2 ”.) 
     As shown in  FIG. 8 , the structure of the peripheral region A 1 -A 2  may be provided between the display region  103  including the pixel region B 1 -B 2  and the driving circuit region C 1 -C 2 . 
     A transistor  110  and a transistor  111  each include a semiconductor layer  142 , a gate insulating layer  143 , a gate electrode layer  145 , a source/drain electrode layer  147 , and the like. In  FIG. 3 , the transistors  110  and  111  each have a top gate/top contact structure. The transistors  110  and  111  are not limited to having such a structure, and may each have a bottom gate structure or a bottom contact structure. In the case where the transistors  110  and  111  each have both of an n channel and a p channel, the transistors  110  and  111  may each have a CMOS structure so as to increase the degree of integration and also realize low power consumption. 
     The first substrate  100  and a second substrate  101  are formed of glass or an organic resin material. A usable organic resin material is, for example, polyimide. The first substrate  100  and the second substrate  101 , when being formed of an organic resin material, may each have a thickness of several micrometers to several ten micrometers, so that the display device  10  is a flexible sheet display. The display device  10  may include a glass cover, a protective film or the like provided on each of second surfaces of the first substrate  100  and the second substrate  101  (namely, outer surfaces of the first substrate  100  and the second substrate  101  as seen in a cross-sectional view, more specifically, a lower surface of the first substrate  100  and an upper surface of the second substrate  102 ). The glass cover, the protective film or the like protects the display device  10  against scratches, breakage or the like. 
     An insulating layer  141  acts as an underlying layer. The insulating layer  141  may be formed of silicon oxide, silicon oxide nitride, silicon nitride, silicon nitride oxide, gallium oxide, hafnium oxide, yttrium oxide, aluminum oxide, aluminum oxide nitride, or the like. The insulating layer  141  may be a single layer or may be a stack of a plurality of layers. The insulating layer  141  may be formed of any of the above-described materials, so as to suppress impurities, typically, an alkaline metal material, water, hydrogen or the like from being diffused from the first substrate  100  into the semiconductor layer  142 . 
     The semiconductor layer  142  may be formed of silicon, silicon germanium, an oxide semiconductor, an organic semiconductor or the like. Examples of usable type of silicon include amorphous silicon, microcrystalline silicon, polycrystalline silicon, single crystalline silicon, and the like. Usable as an oxide semiconductor is at least one metal material among indium, gallium, zinc, titanium, aluminum, tin, hafnium, neodymium, zirconium, lanthanum, cerium and yttrium. The semiconductor layer  142  may be formed of an oxide semiconductor containing indium, gallium and zinc (IGZO). 
     The gate insulating layer  143  may be formed of an insulating material containing at least one of aluminum oxide, magnesium oxide, silicon oxide, silicon oxide nitride, silicon nitride oxide, silicon nitride, gallium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide and tantalum oxide. 
     The insulating layer  149  and an insulating layer  154  may each be formed of any of the above-described materials usable for the gate insulating layer  143 . The insulating layer  149  and the insulating layer  154  may each be a single layer or may be a stack of a plurality of layers. 
     The gate insulating layer  145  and the source/drain electrode layer  147  may each be formed of a metal element selected from tungsten, aluminum, chromium, copper, titanium, tantalum, molybdenum, nickel, iron, cobalt, indium and zinc, an alloy of any of the above-listed metal materials as one component, an alloy obtained as a result of combining any of the above-listed metal materials, or the like. The gate electrode layer  145  and the source/drain electrode layer  147  may each contain nitrogen, oxygen, hydrogen or the like. The gate insulating layer  145  and the source/drain electrode layer  147  may each be a stack of any of the above-listed materials. 
     An insulating layer  150  acts as a flattening film. The insulating layer  150  may be formed of an organic insulating material, an inorganic insulating material, or an insulating material containing an organic insulating material and an inorganic insulating material in a stacking manner. The insulating layer  150  may be formed of, for example, a film containing silicon oxide, silicon nitride or the like, a polymer material such as acrylic resin, polyester, polyamide, polyimide, polysiloxane or the like, or a photosensitive resin. 
     A conductive layer  153  may be formed of any of substantially the same materials as those usable for the gate electrode layer  145  and the source/drain electrode layer  147 . 
     A capacitance element  120  may be provided in a region where a source or drain region of the semiconductor layer  142 , and a conductive layer  146  formed of any of substantially the same materials as those usable for the gate electrode layer  145 , overlap each other while having the gate insulating layer  143  acting as a dielectric layer therebetween. A capacitance element  121  may be provided in a region where the conductive layer  146  and a conductive layer  148   a , which is formed of any of substantially the same materials as those usable for the source/drain electrode layer  147 , overlap each other while having the insulating layer  149  acting as a dielectric layer therebetween. A capacitance element  122  may be provided in a region where the conductive layer  153  and a conductive layer  155  overlap each other while having the insulating layer  154  acting as a dielectric layer therebetween. 
     The light emitting element  130  may include the conductive layer  155 , an organic EL layer  159  and the conductive layer  160 . In an embodiment according to the present invention, the light emitting element  130  has a so-called top emission structure, in which light emitted by the organic EL layer  159  is output toward the conductive layer  160 . The light emitting element  130  is not limited to having a top emission structure, and may have a bottom emission structure. 
     The organic EL layer  159  contains a light emitting material such as an organic electroluminescence material or the like. The organic EL layer  159  may be formed of a low molecular weight-type or high molecular weight-type organic material. In the case of being formed of a low molecular weight-type material, the organic EL layer  159  may include a light emitting layer containing a light emitting organic material and also include a hole injection layer and an electron injection layer or may further include a hole transfer layer and an electron transfer layer. The hole injection layer and the electron injection layer, or the hole transfer layer and the electron transfer layer, when being included, are provided so as to have the light emitting layer therebetween. For example, the organic EL layer  159  may have a structure in which the light emitting layer is held between the hole injection layer and the electron injection layer. The organic EL layer  159  may further include the hole transfer layer, the electron transfer layer, a hole block layer, an electron block layer and the like as necessary, in addition to the hole injection layer and the electron injection layer. 
     The conductive layer  155  preferably has a function of a pixel electrode and also has a light reflecting property. The conductive layer  155  may be formed of, for example, a light reflective metal material such as aluminum (Al), silver (Ag) or the like. Alternatively, the conductive layer  155  may have a structure including a transparent conductive layer formed of ITO (indium tin oxide; tin oxide-containing indium oxide) or IZO (indium zinc oxide; indium oxide-zinc oxide) and a light reflective metal layer in a stacking manner. 
     The conductive layer  160  may be formed of a transparent conductive film such as ITO, IZO or the like, which is light transmissive so as to allow light emitted in the organic EL layer  159  to be transmitted through the conductive layer  160 , and is also conductive. The conductive layer  160  may be formed of an alloy of magnesium and silver. 
     A rib  157  is provided to cover a peripheral portion of the conductive layer  155  and also to form a smooth stepped portion at an edge of the conductive layer  155 . The rib  157  may be formed of an organic resin material. The rib  157  may be formed of, for example, acrylic resin, polyimide resin or the like. 
     A sealing member  173  and a filling member  174  are each formed of an inorganic material, an organic material, or a composite material of an organic material and an inorganic material. The sealing member  173  and the filling member  174  may each be formed of, for example, epoxy resin, acrylic resin, silicone resin, phenol resin, polyimide resin, imide resin, silica gel or the like. 
     A color filter layer  175  has a function of transmitting light of a specific wavelength range. The color filter layer  175  transmits light of, for example, a red, green, blue or yellow wavelength range. In the case where light emitted from the organic EL layer  159  has different colors on a pixel-by-pixel basis, the color filter layer  175  may not be needed. 
     A light blocking layer  177  has a function of blocking light. The light blocking layer  177  may be formed of, for example, a resin containing a pigment dispersed therein, a dye-containing resin, an inorganic material such as black chromium or the like, carbon black, a composite oxide containing solid-solution of a plurality of inorganic oxides, or the like. 
     The flexible printed circuit board  108  may be electrically connected with the conductive layer  148   a  via an anisotropic conductive film  181 . 
     The structure, method or the like described in embodiment 2 may be appropriately combined with a structure, method or the like shown in any other embodiment. 
     Embodiment 3 
     Hereinafter, a method for manufacturing the display device  10  will be described with reference to  FIG. 9  to  FIG. 12 . 
     As shown in  FIG. 9 , the following components are formed on a first surface (upper surface as seen in a cross-sectional view) of the first substrate  100 : the insulating layer  141 , the transistor  110  in the pixel region B 1 -B 2  (the transistor  110  is formed so as to include the semiconductor layer  142 , the gate insulating layer  143  and the gate electrode layer  145 ), the capacitance element  120  (formed to include the conductive layer  146 , the gate insulating layer  143 , and the source/drain region of the semiconductor layer  142 ), the transistor  111  in the driving circuit region C 1 -C 2 , the capacitance element  121  (formed to include the conductive layer  146 , the insulating layer  149 , and the conductive layer  148   a ), the source/drain electrode layer  147 , a first terminal layer (conductive layer)  148   b  in the terminal region D 1 -D 2 , the insulating layer  149 , and the insulating layer  150 . The transistor  110  in the pixel region B 1 -B 2  and the transistor  111  in the driving circuit region C 1 -C 2  have the same structure with each other. 
     The conductive layer  148   a  and the conductive layer  148   b  in the terminal region D 1 -D 2  are formed on the insulating layer  149  and form the same layer as the source/drain electrode layer  147 . As the source/drain electrode layer  147 , a stack of three layers, specifically, a titanium (Ti) layer, an aluminum (Al) layer and a titanium (Ti) layer provided in this order from the lower side may be formed. Each of these layers may be appropriately formed by photolithography, nanoimprinting, ink-jetting, etching or the like so as to have a predetermined shape. 
     Referring to  FIG. 9 , the insulating layer  142  and the insulating layer  149  are each formed by CVD (plasma CVD or thermal CVD), sputtering or the like so as to be a single layer or a stack of a plurality of layers. For example, the insulating layer  149  may be formed by, stacking silicon nitride and silicon oxide. 
     The insulating layer  150  is formed of an organic insulating material on the insulating layer  149 . The organic insulating layer preferably contains a polymer material such as polyester, polyamide, polyimide, polysiloxane or the like. The insulating layer  150  of such an organic insulating material is formed on generally the entirety of the first surface of the first substrate  100  by spin-coating, ink-jetting, laminating, dip-coating, vapor deposition polymerization or the like. The insulating layer  150  is preferably formed to have a thickness of 1 μm or greater. With such a thickness, the insulating layer  150  compensates for concaved and convexed portions provided by the transistor  110  to provide a flat surface above the first substrate  100 . 
     Next, as shown in  FIG. 10 , the following components are formed on the insulating layer  150  in the pixel region B 1 -B 2 : the capacitance element  122  (formed to include the conductive layer  153 , the insulating layer  154 , and the conductive layer  155 ), the light emitting element  130  (formed to include the conductive layer  155 , the organic EL layer  159 , and the conductive layer  160 ), and the rib  157 . Each of the components may be appropriately formed by photolithography, nanoimprinting, ink-jetting, etching or the like so as to have a predetermined shape. 
     The conductive layer  153  and the conductive layer  155  may be formed by sputtering, vapor deposition, plating or the like to have a thickness of several ten nanometers to several hundred nanometers. For example, the conductive layer  153  may be formed by stacking molybdenum, aluminum and molybdenum by use of sputtering. The conductive layer  155  may be formed by, for example, stacking ITO, silver and ITO by use of sputtering. 
     The insulating layer  154  may be formed of CVD (plasma DVD or thermal CVD), spin-coating, printing or the like. For example, the insulating layer  154  may be formed of silicon nitride by plasma CVD. 
     The rib  157  is formed to have an opening exposing an upper surface of the conductive layer  155 . An edge of the opening of the rib  157  preferably has a smooth tapering shape. This improves the step coverage. The rib  157  may be formed so as not to be on an upper surface of the conductive layer  148   b  in the terminal region D 1 -D 2 , or may be formed to have an opening exposing the upper surface of the conductive layer  148   b . The rib  157  may be formed to have a thickness of several micrometers. The rib  157  may be formed of polyimide by spin-coating. 
     The organic EL layer  159  is preferably formed to at least overlap the conductive layer  155 . The organic EL layer  159  is formed by, for example, vacuum vapor deposition, printing, spin-coating or the like. In the case of being formed by vacuum vapor deposition, the organic EL layer  159  is preferably formed by use of a shadow mask so as not to be in the terminal region D 1 -D 2 . The organic EL layer  159  may be formed of different materials among pixels adjacent to each other, or may be formed of the same material in all the pixels. In the case where the organic EL layer  159  outputting white light is formed so as to be included in all the pixels, the color filter  175  or the like may be used, so that light of different colors is output from different pixels. 
     After the organic EL layer  159  is formed, the conductive layer  160  is formed. The conductive layer  160  is formed of a light transmissive conductive material by sputtering. In the case where, for example, the light emitting element  130  is of a top emission type, by which light is output from the conductive layer  160 , the conductive layer  160  preferably has a uniform thickness. 
     The conductive layer  160  may be formed by vacuum vapor deposition or sputtering. The conductive layer  160  may not be formed in the terminal region D 1 -D 2 , or may be removed from the terminal region D 1 -D 2  after being formed. The conductive layer  160  may be formed of IZO by sputtering. Alternatively, the conductive layer  160  may be formed of an alloy of magnesium and silver. 
     Next, the sealing film  161  is formed. 
     First, as shown in  FIG. 11 , the inorganic insulating layer  162  is formed on the conductive layer  160  and the insulating layer  149 . The inorganic insulating layer  162  may be formed by CVD (plasma CVD or thermal CVD), sputtering, spin-coating, printing or the like. For example, the inorganic insulating layer  162  may be formed of silicon nitride by plasma CVD. 
     Next, the organic insulating layer  163  is formed on the inorganic insulating layer  162 . The organic insulating layer  163  may be formed by vacuum vapor deposition, printing, spin-coating or the like. For example, the organic insulating layer  163  may be formed of acrylic resin by spin-coating. It is preferable that the peripheral region A 1 -A 2  includes a region where the organic insulating layer  163  has been removed. 
     Next, the inorganic insulating layer  164  is formed on the organic insulating layer  163 . The inorganic insulating layer  164  may be formed by substantially the same method as that of the inorganic insulating layer  162 . For example, the inorganic insulating layer  164  may be formed of silicon nitride by plasma CVD. 
     Next, the organic insulating layer  165  is formed on the inorganic insulating layer  164 . The organic insulating layer  165  may be formed by substantially the same method as that of the organic insulating layer  163 . For example, the organic insulating layer  163  may be formed, by spin-coating, of an acryl resin film containing phenolphthalein and sodium carbonate at 3% by weight in sum with respect to the total weight of the resin film. It is preferable that the peripheral region A 1 -A 2  includes a region where the organic insulating layer  165  has been removed. 
     Next, the inorganic insulating layer  169  is formed on the organic insulating layer  165  and the inorganic insulating layer  164 . The inorganic insulating layer  169  is formed in substantially the same method as that of the inorganic insulating layer  162 . For example, the inorganic insulating layer  169  may be formed by stacking silicon oxide and silicon nitride. 
     The peripheral region A 1 -A 2  includes a region where the insulating layer  150  and the rib  157  have been removed. The insulating layer  154  is formed on a side surface, as well as on an upper surface, of the insulating layer  150  and also on an upper surface of the insulating layer  149 . The conductive layer  160  is formed on a side surface, as well as on an upper surface, of the rib  157  and also on an upper surface of the insulating layer  154 . 
     As described above, the peripheral region A 1 -A 2  includes a region in which the insulating layer  150  and the rib  157 , which are formed of an organic insulating material, have been removed, and in which the insulating layer  154  and the conductive layer  160 , which are formed of an inorganic material, are formed. With such a structure, the insulating layer  150  and the rib  157 , which are formed of an organic insulating material, are held between the layers each formed of an inorganic material. This structure prevents permeation of moisture from the peripheral region A 1 -A 2  into the pixel region B 1 -B 2 . The combination of the inorganic insulating layer  162 , the inorganic insulating layer  164  and the inorganic insulating layer  169  included in the sealing film  161  in an embodiment according to present invention further enhance the moisture blocking effect. Therefore, the above-described region acts as a moisture blocking region  179 , and the structure thereof may be considered as a “moisture blocking structure”. 
     As shown in  FIG. 8 , the above-described structure may be provided between the display region including the pixel region B 1 -B 2  and the driving circuit region C 1 -C 2 , so that the moisture blocking effect is further enhanced. 
     In the case where the moisture absorption layer  166  is formed on the inorganic insulating layer  169  as shown in  FIG. 6  and  FIG. 7 , the moisture absorption layer  166  may formed by spin-coating, spraying, ink-jetting or the like. For example, the moisture absorption layer  166  may be formed to contain a silicon-containing polymer by spin-coating. 
     In the case where the gas releasing layer  167  is formed on the moisture absorption layer  166 , the gas releasing layer  167  may be formed by spin-coating, spraying, ink-jetting or the like. For example, the gas releasing layer  167  may be formed to contain a thermosetting resin or a thermoplastic resin such as acrylic resin, polyimide resin, epoxy resin or the like by spin-coating. 
     Next, as shown in  FIG. 12 , on the second substrate  101 , the color filter layer  175  and the light blocking layer  177  are formed. Then, the second substrate  101  and the first substrate  100  are bonded together with the sealing member  173  and the filling member  174 . 
     The light blocking layer  177  may be formed by spin-coating, spraying or ink-jetting. The light blocking layer  177  may be formed to have an opening in a region in the pixel region B 1 -B 2  where light from the light emitting element  130  is output. For example, the light blocking layer  177  may be formed of a photosensitive organic resin containing a black pigment (i.e., formed of a black resist) by spin-coating. 
     The color filter layer  175  is formed, by printing, ink-jetting, etching using photolithography or the like, in the region in the pixel region B 1 -B 2  where the light from the light emitting element  130  is output. In the case where the organic EL layer  159  is formed of different materials on a pixel-by-pixel basis, the color filter layer  175  may not be needed. 
     Before the first substrate  100  and the second substrate  101  are bonded together with the sealing member  173  and the filling member  174 , a spacer or the like may be provided in advance in order to stabilize the distance between the first substrate  100  and the second substrate  101 . The spacer may be formed of either an organic insulating material or an inorganic insulating material. In the case where the filling member  174  is formed of a photocurable adhesive, the filling member  174  is cured quickly and thus the work time is shortened. 
     The flexible printed circuit board  108  may be electrically connected with the conductive layer  148   b  by use of the anisotropic conductive film  181 . At this point, it is preferable that the insulating layers included in the sealing film  161  (i.e., the inorganic insulating layer  162 , the organic insulating layer  163 , the inorganic insulating layer  164 , the organic insulating layer  165 , and the inorganic insulating layer  169 ), the moisture absorption layer  166  and the gas releasing layer  167  may be removed from the terminal region D 1 -D 2  by laser radiation or the like. The anisotropic conductive film  181  may be formed by application of a resin containing metal particles such as silver particles, copper particles or the like. 
     With manufacturing method in the above-described embodiment, a display device having both of a function of detecting moisture permeation into any part of a display region covered with a sealing film and a sealing performance of a sufficiently high level to prevent permeation of moisture into a light emitting element is manufactured. 
     The structure, method or the like described in embodiment  3  may be appropriately combined with a structure, method or the like shown in any other embodiment.