Abstract:
A display device includes a transparent plate having a first area and a second area, a first conductive line on the second area of the transparent plate, a substrate having a third area and a fourth area on the first area of the transparent plate, a display element on the third area of the substrate, and a second conductive line on the fourth area of the substrate. The second conductive line is electrically coupled between the display element and the first conductive line, and the first and second conductive lines are on different planes.

Description:
This application claims the benefit of Korean Patent Application No. 10-2007-0028502, filed on Mar. 23, 2007, which is hereby incorporated by reference as if fully set forth herein. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a display device, and more particularly to an interconnection of a display device including an OLED. 
     2. Discussion of the Related Art 
     In a multimedia age, it is required for a display device to be finer and larger and to express colors close to natural colors. There are limits to a CRT (Cathode Ray Tube) which is a conventional general display device. An LCD (Liquid Crystal Display), a PDP (Plasma Display Panel), an OLED (Organic Light Emitting Diode), a projection TV (Television) and the like are developing at a high speed to be widely used in a field of high-definition images. 
     Among the above-mentioned display devices, the OLED is a self light emitting display device, which has advantages such as a large viewing angle, excellent contrast and fast response time. Generally, an organic EL device has a structure in which an anode is formed on a substrate, and a hole injecting layer, a hole transporting layer, a light emitting layer, an electron transporting layer and a cathode are sequentially formed on the anode. Further, when a voltage is applied between the anode and the cathode, holes injected from the anode move to the light emitting layer through the hole transporting layer. Meanwhile, electrons are injected into the light emitting layer from the cathode through the electron transporting layer. In a region of the light emitting layer, carriers are recombined to produce excitons. The excitons move from an excited state to a ground state. Accordingly, fluorescent molecules of the light emitting layer emit light to form an image. 
     However, the above-mentioned conventional display devices such as an OLED have the following problems. 
     It is impossible to stably manufacture a display device such as an OLED on general glass and plastic in the recent technology. For example, since the OLED has an advantage capable of being bent or crooked, it is manufactured using a high priced special substrate. Accordingly, when the substrate including the OLED is used as a display device in an electronic product and the like, there are the following problems. 
       FIG. 1  illustrates a plan view showing an interconnection structure of a substrate including an OLED in the prior art. An OLED device  100  is formed on a substrate  110  in  FIG. 1 . In this case, although the OLED device including four pixels is schematically depicted in  FIG. 1 , the OLED device is generally formed of more pixels to transfer image information or text information. In this case, the OLED device is used as a display device of an application product  130  such as an air conditioner. Thus, the substrate  110  with the OLED device  100  is attached to one surface of the application product  130 . Further, a transparent conductive material  120  is formed on the substrate  110  to connect the respective pixels to electrode lines  140  of the application product  130 . That is, the transparent conductive material  120  serves to transfer current, light emitting signals and the like to the respective pixels of the OLED device  100 . 
     In this case, the transparent conductive material  120  formed on the substrate  110  is formed of ITO (Indium-Tin-Oxide). Further, as shown in  FIG. 1 , since the area of the transparent conductive material  120  is larger than the area of the OLED device  100  in the substrate  110 , there is a problem of spending the manufacturing cost for a high priced substrate. That is, only a portion, for example, a central portion of the high priced substrate is used to manufacture a light emitting device and the other portion thereof is wasted. That is, since it is impossible to stably manufacture a display device on general glass and plastic in the recent technology, when it is impossible to form a display device on a substrate having the same area as a small area of an application product, the cost is wasted. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to a display device that substantially obviates one or more problems due to limitations and disadvantages of the related art. 
     An object of the present invention is to provide a display device and a temperature control unit having the display device which is capable of minimizing the manufacturing cost of a panel and the like by minimizing the waste of the substrate when a light emitting device such as an OLED is formed on a substrate. 
     Another object of the present invention is to provide a display device and a temperature control unit having the display device which is capable of manufacturing substrates having various shapes and sizes using general glass and plastic, thereby enabling various design applications. 
     Yet another object of the present invention is to provide a display device and a temperature control unit having the display device which is capable of improving a display effect by using a color substrate as a sealing layer. 
     Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
     To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a display device includes a substrate with a display element; and a transparent plate which is in contact with the substrate and has a larger area than that of the substrate. 
     In accordance with another aspect of the present invention, there is provided a display device comprising a substrate with a display element; an encapsulating plate formed on the substrate; and a transparent plate with the encapsulating plate inserted therein. In this case, contact points of lines of the display device and a transparent conductive material may be formed at a periphery of the encapsulating plate. 
     It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings: 
         FIG. 1  illustrates a plan view showing an interconnection structure of a substrate including an OLED in the prior art; 
         FIGS. 2A to 2D  illustrate a display device according to a first embodiment of the present invention and first and second substrates thereof; 
         FIGS. 3A and 3B  illustrate a display device according to a second embodiment of the present invention and first and second substrates thereof; 
         FIGS. 4A and 4B  illustrate a display device according to a third embodiment of the present invention and first and second substrates thereof; 
         FIG. 5  illustrates an air conditioner having the display device according to the present invention; 
         FIG. 6  illustrates a refrigerator having the display device according to the present invention; and 
         FIG. 7  illustrates a mobile phone having the display device according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. 
     Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
     A dimension of a thickness is enlarged in the accompanying drawings to clearly represent several layers and regions. A thickness ratio of respective layers shown in the drawings is not equal to an actual thickness ratio. Meanwhile, when a portion such as a layer, a film, a region and a plate is formed or disposed “on” the other portion, it should be understood that the portion may be formed directly on the other portion through a direct contact, or another portion may be disposed therebetween. 
     A display device according to the present invention is characterized by using two substrates, wherein one substrate includes a display element and the other substrate includes lines. The lines serve to transfer current, driving signals and the like to the display device. 
       FIGS. 2A to 2D  illustrate a display device according to a first embodiment of the present invention and first and second substrates thereof. The display device according to the first embodiment of the present invention is explained below with reference to  FIGS. 2A to 2D . 
     First,  FIG. 2A  shows a display element  200  including pixels  205 . In this case, the substrate may be formed of different materials according to types of the pixels  205  formed on the substrate. Further, the pixels  205  include OLED, PDP and LCD pixels and the like to display text, image information and the like. That is, the display element  200  includes a plurality of pixels. As the respective pixels are operated on and off, the display element  200  can display text, a pattern or a moving picture and the like. Further, as shown in the drawings, it is preferable that the pixels  205  include a plurality of pixels. Further, since text or image information is displayed according to whether the respective pixels are operated on and off, it is preferable to independently apply driving signals to the respective pixels. Thus, as shown in the drawings, lines  206  are formed for the respective pixels, and two lines  206  are formed for each pixel in this embodiment. 
     If an OLED is used as a display device, an anode, a hole injecting layer, a hole transporting layer, a light emitting layer, an electron transporting layer and a cathode are sequentially formed on the substrate. In this case, electrode lines are respectively connected to the anode and the cathode of the OLED, independently of lines formed on the second substrate. 
     Further,  FIG. 2B  shows a transparent plate  210  with a transparent conductive material  220  formed thereon. In this case, although lines formed on the transparent plate  210  are not necessarily transparent, it is preferable that the electrode is formed of a transparent material in case of using the transparent conductive material  220  or in order to improve the aesthetic effect of the display device. Further, the transparent plate  210  may be formed of glass, plastic or the like. For example, the transparent conductive material  220  may be formed of ITO, IZO, SiO 2 , ZnO or the like. Further, the transparent conductive material  220  is divided into four portions in  FIG. 2B  to apply driving signals to the respective pixels as will be described later. Further, although the transparent conductive material  220  is formed of a transparent material, the transparent conductive material  220  is represented by oblique lines in  FIG. 2B  to distinguish the transparent conductive material  220  from the transparent plate  210 . 
       FIG. 2C  illustrates a display device in which the display element  200  is coupled to the transparent plate  210 . Specifically,  FIG. 2C  shows a side view of the display element  200  coupled to a central portion of the transparent plate  210 . In this case, the structure of pixels and lines formed on the display element  200  is omitted, and the transparent conductive material  220  formed on the transparent plate  210  is partially contacted to the display element  200 . Such contact points are connecting portions to apply driving signals to a light emitting device. Further, as shown in  FIG. 2C , a central portion of the transparent plate  210  covers the display element  200 . Accordingly, if the light emitting device is an OLED in this embodiment, the central portion of the transparent plate  210  may serve as a sealing layer. Further, although a bottom emission type OLED is shown in  FIG. 2C , it may be a top emission type OLED. 
       FIG. 2D  illustrates a plan view of the display device shown in  FIG. 2C . As shown in  FIG. 2D , the transparent conductive material  220  is formed on the transparent plate  210 . Further, the display element  200  is formed on the central portion of the transparent plate  210 . In this case, a plurality of pixels is formed on the display element  200  and the respective pixels are connected to the transparent conductive material  220  through the lines. Further, although not shown in the drawings, the transparent plate  210  is disposed on a body of an application product and the transparent conductive material is electrically connected to the application product such that driving signals, power and the like are supplied to the transparent conductive material. 
     In this case, the application product means a product using a display device including the above-described display element  200  and transparent plate  210 . That is, although the above-described display device is used as an independent device, the display device may be used as a part of various types of application products, which will be described later. 
     An effect of the display device according to the first embodiment of the present invention is explained below. 
     In this embodiment, the pixels of the OLED are formed on the substrate, and the transparent plate is in contact with the substrate to seal the pixels, thereby serving as an encapsulating plate. Further, the transparent plate has a size larger than the size of the pixels of the OLED. When it is applied to an electronic product or the like, the transparent plate can be formed to have a size and a shape equal or similar to those of one surface of the electronic product. Accordingly, as a result, the transparent plate made of glass, plastic or the like which is coated on one surface of the electronic product serves as an encapsulating plate of the OLED. Thus, when a light emitting device such as an OLED is applied to an electronic product, it is possible to minimize the manufacturing cost of a panel and the like by minimizing the waste of the substrate. Further, since it is easy to manufacture general glass and plastic in a desired shape, it is possible to manufacture substrates having various shapes and sizes when it is applied to a product, thereby enabling various design applications. 
       FIGS. 3A and 3B  illustrate a display device according to a second embodiment of the present invention and first and second substrates thereof. The display device according to the second embodiment of the present invention is explained below with reference to  FIGS. 3A and 3B . 
     In  FIG. 3A , a metal  225  is formed on the transparent plate  210  and the metal  225  is formed of thin metal. That is, this embodiment features that driving signals are applied to a light emitting device through the thin metal  225  instead of the transparent conductive material of the above embodiment. In this case, the metal  225  is formed of a conductive material. The metal  225  should have a thickness which is difficult to be cut, but if the thickness of the metal  225  is excessively large, it may ruin the beauty of the light emitting device. If the metal  225  is manufactured to have a diameter of 1 mm or less, it is possible to ensure durability without ruining the beauty. Further,  FIG. 3B  illustrates a plan view of the display device in which a first substrate  310  is coupled to the second substrate  210  shown in  FIG. 3A . In this case, the display element  200  is equal to the display element  200  shown in the first embodiment. Accordingly, pixels and lines of an OLED or the like are formed on the display element  200 . The lines are connected to the metal  225  formed on the transparent plate  210  to receive driving signals of the light emitting device. 
     In the display device according to the second embodiment of the present invention, when a light emitting device of an OLED is applied to a substrate, it is possible to minimize the manufacturing cost of a panel and the like by minimizing the waste of the substrate. Further, it is possible to transfer driving signals through thin metal. Furthermore, as described above, the pixels of the OLED are formed on the substrate and the transparent plate is in contact with the substrate to seal the pixels, thereby serving as an encapsulating plate. 
       FIGS. 4A and 4B  illustrate a display device according to a third embodiment of the present invention and first and second substrates thereof. The display device according to the third embodiment of the present invention is explained below with reference to  FIGS. 4A and 4B . 
     This embodiment features that a groove is formed on the central portion of the transparent plate. Further, an encapsulating plate of the display device is formed to have a smaller size than that of the display device. In this case, the encapsulating plate is inserted into the groove. 
     First,  FIG. 4A  shows the transparent plate  210  with the transparent conductive material  220  formed thereon. Further, a groove  212  is formed in the transparent plate  210 . Although the groove  212  formed in a rectangular shape is shown in  FIG. 4A , the groove  212  may be formed in different shapes such as a triangular shape or a circular shape. The shape of the groove  212  may be selected according to the shape of the display device. Further, as described above, metal may be formed instead of the transparent conductive material  220 . 
     Next,  FIG. 4B  illustrates a display device in which the display element  200  is coupled to the transparent plate  210 . In this case, although not shown in the drawings, the pixels and lines are formed on the display element  200 . Further, an encapsulating plate  215  is formed on the display element  200  to seal the display element  200 . Further, the encapsulating plate  215  is inserted into the groove  212  inside of the transparent plate  210 . In  FIG. 4B , the transparent conductive material  220  formed on the transparent plate  210  is partially contacted to the display element  200 . Contact points  250  are shown in  FIG. 4B , and driving signals of the light emitting device are transferred to the display element  200  through the contact points  250 . Further, the display device shown in  FIG. 4B  is a top emission type device if a light emitting device is an OLED, and may be a bottom emission type device. 
     In the display device according to the third embodiment of the present invention, the groove is formed in the substrate. Accordingly, it is possible to minimize the manufacturing cost of a panel and the like by minimizing the waste of the substrate. Further, light emitted from the pixels is directly emitted to the outside without passing through the transparent plate. Thus, reproducibility of color purity is further enhanced. 
     The above-described display device according to the present invention can be used in various application products. In this case, the display device can display operation characteristics of the product and the like by driving signals applied from the lines connected to the application product. 
     Specifically, an example in which the display device is used in an air conditioner is explained. As shown in  FIG. 5 , a display device  550  disposed at an outer portion of an air conditioner  500  may display a room temperature, a setting state of the air conditioner and the like. In this case, the above-described display device makes it possible to reduce the manufacturing cost without ruining the beauty of the display. Further, when a chromatic substrate is used instead of the transparent plate, it is possible to improve the beauty of the display device. Although the transparent plate is formed at a portion of a front surface of a body of the air conditioner in  FIG. 5 , if the transparent plate is formed on the whole front surface of the body, it may promote the beauty. Further, the body of the air conditioner may have a circular, triangular or star shape instead of a rectangular shape, and the transparent plate may be formed in the same shape as the body of the air conditioner. In this case, it is possible to obtain an aesthetic effect and an advantage in a manufacturing process since it is easy to join the transparent plate to the air conditioner. 
     Further, as shown in  FIG. 6 , a display device  650  disposed at an outer portion of a refrigerator  600  may display a cooling state, temperature setting and the like. In this case, the display device including the display element, the transparent plate and the like makes it possible to reduce the manufacturing cost without ruining the beauty of the display. Further, as described above, when a chromatic substrate is used instead of the transparent plate, it is possible to improve the beauty of the display device. 
     Further, as shown in  FIG. 7 , a display device  750  disposed at an outer portion of a mobile phone  700  may display dialing and dialed numbers, text information and the like. Further, the display device  750  has the same configuration as the above-described air conditioner, refrigerator or the like. Further, although four OLED pixels are shown in  FIG. 7 , a number of the pixels sufficient to display a text message, a moving picture and the like are provided on the entire screen. Further, although respective components, a transparent conductive material and the like are shown to be distinguishable to promote the understanding, they cannot be easily distinguished with the naked eye. 
     In the above-described display device and a temperature control unit including the same according to the present invention, when a light emitting device such as an OLED is formed on a substrate, it is possible to minimize the manufacturing cost of a panel and the like by minimizing the waste of the substrate. Further, since it is easy to manufacture general glass and plastic in a desired shape, it is possible to manufacture substrates having various shapes and sizes when it is applied to a product, thereby enabling various design applications. 
     That is, the display device according to the present invention can be used in various electronic products, for example, a washing machine, a power unit such as a vacuum cleaner in addition to the above-described temperature control units such as a refrigerator and an air conditioner. Further, even in application products except electronic products, when it is necessary to display information regarding a product and the like, the display device may be attached to the product and used. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.