Abstract:
A light-emitting element display device includes: a display area which has an organic insulating layer that is made of an organic insulating material; a peripheral circuit area which is disposed around the display area and which has the organic insulating layer; and a blocking area that is formed between the display area and the peripheral circuit area. The blocking area includes: a first blocking area configured by only one or a plurality of inorganic material layers between an insulating base substrate and an electrode layer which covers the display area and is formed continuously from the display area, and which configures one of two electrodes for allowing the light emitting area to emit the light; and a second blocking area including a plurality of layers configuring the first blocking area, and a light emitting organic layer.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority from Japanese application JP2013-139743 filed on Jul. 3, 2013, the content of which is hereby incorporated by reference into this application. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a light-emitting element display device, and more particularly to a light-emitting element display device that allows light-emitting elements which are self-luminous bodies arranged in respective pixels to emit a light for displaying. 
     2. Description of the Related Art 
     In recent years, an image display device using self-luminous bodies called “organic light emitting diode (OLED)” has been put into practical use, hereinafter the image display device is called “organic EL (electro-luminescent) display device”. As compared with a related-art liquid crystal display device, the organic EL display device is not only excellent in visibility and response speed because the self-luminous bodies are used, but also can be further thinned because no auxiliary illuminating device such as a backlight is required. 
     The organic EL display device thus configured is deteriorated with the absorption of moisture. For that reason, an organic EL panel includes a countermeasure that a sealing glass substrate is stuck onto a TFT (thin film transistor) substrate on which a light emitting layer is formed with a resin for sealing. 
     JP 2004-335267 A and JP 2008-047515 A disclose a structure in which an organic film is divided between a display area and an area around an outside of the display area in view of an entry route in which the moisture arrives at the display area from the area around the outside of the display area through the organic film. 
     SUMMARY OF THE INVENTION 
     A sealing film is formed on a surface of a TFT substrate so as to cover an overall surface of the display area and a peripheral circuit area. However, if a foreign matter adheres to any portion in a process before the sealing film is formed, the portion cannot be sufficiently covered with the sealing film, as a result of which the portion may configure the entry route of the moisture from the external. In particular, in a deposition process before the sealing film is formed, the foreign matter that has adhered to a vapor deposition mask may be transferred to the TFT substrate side during the deposition process. In this case, it is conceivable that sealing using the sealing film is insufficient. 
     The present invention has been made in view of the above-mentioned circumstance, and therefore an object of the present invention is to provide an organic EL display device that can suppress a display failure attributable to the moisture entry, and maintain a long-term quality. 
     According to the present invention, there is provided a light-emitting element display device including: a display area in which pixels each having a light emitting area that spontaneously emits a light are arranged in a matrix and which has an organic insulating layer that is made of an organic insulating material; a peripheral circuit area which is disposed around the display area, in which a metal wiring or a circuit using a thin film transistor is arranged and which has the organic insulating layer; and a blocking area that is formed between the display area and the peripheral circuit area, in which the blocking area includes: a first blocking area configured by only one or a plurality of layers made of inorganic material between an insulating substrate made of a base material and an electrode layer which covers the display area and is formed continuously from the display area, and which configures one of two electrodes for allowing the light emitting area to emit the light; and a second blocking area including a plurality of layers configuring the first blocking area, and a light emitting organic layer. 
     In this example, the light emitting organic layer means at least one of layers formed between the two electrodes, and specifically includes a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer in addition to a light emitting layer that emits a light. 
     Also, in the light-emitting element display device according to the present invention, the light emitting organic layer may include a light emitting layer that covers the display area made of an organic light emitting material. 
     Also, in the light-emitting element display device according to the present invention, the light emitting organic layer includes any one of a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer. 
     According to the present invention, there is provided a method of manufacturing a light-emitting element display device, including the steps of: forming a circuit including a TFT (thin film transistor) in a display area and a peripheral circuit area around the display area on an insulating substrate; forming an electrode electrically connected to the circuit in each of pixels within the display area, and an organic insulating film formed around the electrode; depositing a light emitting organic layer with the use of an evaporation mask having a mask area that covers the peripheral circuit area, and comes in contact with only the peripheral circuit area; and forming a sealing film that covers at least the light emitting organic layer for sealing an overall surface of the insulating substrate. 
     Also, in the method of manufacturing a light-emitting element display device according to the present invention, in the step of forming the light emitting organic layer, an inner end of the evaporation mask is arranged within a blocking area that is formed between the display area and the peripheral circuit area. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram schematically illustrating an organic EL display device according to an embodiment of the present invention; 
         FIG. 2  is a plan view illustrating a configuration of a TFT substrate in the organic EL display device; 
         FIG. 3  is a cross-sectional view taken along a line III-III of  FIG. 2 ; 
         FIG. 4  is a flowchart illustrating a process of manufacturing the organic EL display device according to the embodiment of the present invention; 
         FIG. 5  is a flowchart illustrating the detail of a TFT substrate manufacturing process in  FIG. 4 ; 
         FIG. 6  is a diagram illustrating an light emitting organic layer forming process and a cathode/sealing film forming process in  FIG. 5  in detail; 
         FIG. 7  is a diagram illustrating a light emitting organic layer forming process and a cathode/sealing film forming process of a TFT substrate according to a comparative example 1; and 
         FIG. 8  is a diagram illustrating a light emitting organic layer forming process and a cathode/sealing film forming process of a TFT substrate according to a comparative example 2. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, the same or equivalent elements are denoted by identical symbols, and a repetitive description thereof will be omitted. 
       FIG. 1  is a diagram schematically illustrating an organic EL display device  100  according to an embodiment of the present invention. As illustrated in the figure, the organic EL display device  100  is configured by an organic EL panel  200  fixedly sandwiched between an upper frame  110  and a lower frame  120 . The organic EL panel  200  is configured by a TFT substrate  300  which will be described later, and a sealing substrate not shown which is adhered to the TFT substrate  300  with a transparent resin. 
       FIG. 2  is a plan view illustrating a configuration of the TFT substrate  300 . As illustrated in the figure, the TFT substrate  300  includes a display area  320  in which pixels  310  each having an anode electrode  359  (to be described later) arranged therein, and emitting a light on the basis of a gradation value are arranged in a matrix, a peripheral circuit area  340  that is arranged around the display area  320  in which various signal generator circuits for driving pixel circuits, and a circuit that applies a potential to a cathode electrode  357  (to be described later) are formed, and a blocking area  330  that is formed between the display area  320  and the peripheral circuit area  340 . Also, a driving IC (integrated circuit)  350  that conducts a control for allowing the respective pixels  310  in the display area  320  to emit the light in correspondence with the gradation value is arranged on the TFT substrate  300 . 
       FIG. 3  is a cross-sectional view taken along a line III-III of  FIG. 2 . As illustrated in  FIG. 3 , the TFT substrate  300  includes a pixel circuit  361  and a peripheral circuit  362  made of, for example, an LTPS (low-temperature polysilicon) within inorganic insulating films  352  and  353 , and an organic flattening film  355  which is an organic insulating film for flattening an area in which the pixel circuit  361  and the peripheral circuit  362  are mainly formed, over a glass substrate  351  which is an insulating substrate. The TFT substrate  300  also includes an organic bank  356  which is an organic insulating film formed to cover an end of a conductive film such as an anode electrode  359  formed in a through-hole of the organic flattening film  355 , and a reflection film  360  that is arranged on the glass substrate  351  side of the anode electrode  359  for reflecting a received light. The TFT substrate  300  further includes a light emitting organic layer  358  formed of a light emitting layer that emits the light, and/or hole injection/transport layers and electron injection/transport layers, the cathode electrode  357  which is an electrode facing the anode electrode  359 , and a sealing film  354  formed to cover the overall surface of the TFT substrate  300 . 
     In this example, the blocking area  330  is configured to block passing of moisture between the display area  320  and the peripheral circuit area  340 . The blocking area  330  includes a first blocking area  331  spread between the cathode electrode  357  and the glass substrate  351 , and made of only an inorganic material, and a second blocking area  332  including the respective films of the first blocking area  331 , and also having the light emitting organic layer  358 . Because moisture entering from the external is advanced through an organic film, for example, the moisture that has entered the peripheral circuit area  340  can be prevented from entering the display area  320  with the provision of an area made of only an inorganic material. 
     Hereinafter, a method of manufacturing the configuration according to this embodiment will be described together with advantages of the configuration according to this embodiment. 
       FIG. 4  is a flowchart illustrating a process of manufacturing the organic EL display device  100  according to the embodiment of the present invention. As illustrated in the flowchart, in the process of manufacturing the organic EL display device  100 , the TFT substrate  300  is first manufactured in a TFT substrate manufacturing process S 100 , and a sealing substrate is sequentially manufactured in a sealing substrate manufacturing process S 200 . Then, in a TFT substrate/sealing substrate adhering process S 300 , the TFT substrate  300  and the sealing substrate thus manufactured are adhered to each other with a transparent resin, and in an upper and lower frame fitting process S 400 , external members (not shown) such as a COG and an FPC are implemented, and the upper frame  110  and the lower frame  120  are fitted to those components. With the above processes, the organic EL display device  100  is completed. 
       FIG. 5  is a flowchart illustrating the detail of the TFT substrate manufacturing process S 100  in  FIG. 4 . As illustrated in this flowchart, in the TFT substrate manufacturing process S 100 , a transistor circuit made of, for example, an LIPS is first formed in a TFT circuit forming process S 110 . The anode electrode  359  and the organic bank  356  are then formed in an anode/organic bank forming process S 120 . Sequentially, the light emitting organic layer  358  is formed by vapor deposition in a light emitting organic layer forming process S 130 . Finally, in a cathode/sealing film forming process S 140 , after the cathode electrode  357  that covers the display area  320 , and extends to the peripheral circuit area  340  has been formed, the sealing film  354  that covers the overall surface of the substrate is formed to complete the TFT substrate  300 . 
       FIG. 6  is a diagram illustrating the detail of the light emitting organic layer forming process S 130  and the cathode/sealing film forming process S 140 . As described above, the light emitting organic layer  358  is formed by so-called “vapor deposition”. The vapor deposition is conducted in such a manner that a portion of the TFT substrate  300  where no film is formed is covered with an evaporation mask  410 , and a film forming material is attached onto a portion of the TFT substrate  300  which is not covered with the evaporation mask  410 . In this embodiment, the evaporation mask  410  that comes in contact with the peripheral circuit area  340 , but comes out of contact with the display area  320  is used. Referring to  FIG. 6 , in order to describe the advantages of this embodiment, a case in which a foreign matter  411  is present in a portion corresponding to the peripheral circuit area  340  that comes in contact with the evaporation mask  410  will be described. First, in a mask loading process S 131 , the evaporation mask  410  is loaded on the TFT substrate  300 . In this example, the inner end of the evaporation mask  410  is arranged in the blocking area  330  so that the light emitting organic layer  358  is formed within the blocking area  330 , taking adhesion caused by go-around of the light emitting organic layer  358  in the deposition process into account. Then, in a deposition process S 132 , the light emitting organic layer  358  is deposited. In this process, it is assumed that the foreign matter  411  is transferred to the peripheral circuit area  340  from the evaporation mask  410 . Finally, in the cathode/sealing film forming process S 140 , the cathode electrode  357  and the sealing film  354  are formed. However, because the sealing film  354  is not appropriately formed in a portion to which the foreign matter  411  adheres, the portion may configure an entry route of the moisture. 
     However, in the TFT substrate  300  according to this embodiment, because the cathode electrode  357  to the glass substrate  351  in the first blocking area  331  are made of only the inorganic material, moisture that has entered the peripheral circuit area  340  is blocked in the first blocking area  331  so that the moisture can be prevented from entering the display area  320 , as indicated by an arrow in the figure. Therefore, there can be provided the organic EL display device that can suppress the display failure and maintain the quality for a long period. 
     Although the above-mentioned light emitting organic layer  358  may be formed by any number of layers, the light emitting organic layer  358  is generally configured by a plurality of layers. In this case, the deposition process using the above-mentioned evaporation mask  410  is repeated a plurality of times. Also, the plurality of layers may be configured by light emitting layers that emit light, or may be configured by a hole injection layer, a hole transport layer, an electron injection layer, or an electron transport layer. In particular, in the organic EL display device in which the overall surface of the display area  320  emit light with a single color such as white, the light emitting layer can be configured by the light emitting organic layer  358 . In the organic EL display device in which the light emitting layers of RGB are formed for each of the pixels, separately, a common layer formed commonly to the respective pixels among the hole injection layer, the hole transport layer, the electron injection layer, and the electron transport layer may be formed by the light emitting organic layer  358 . 
       FIG. 7  is a diagram illustrating a light emitting organic layer forming process and a cathode/sealing film forming process of a TFT substrate according to a comparative example 1. The light emitting organic layer forming process and the cathode/sealing film forming process of the comparative example 1 are identical with those in  FIG. 6  in that a mask loading process S 231 , a deposition process S 232 , and a cathode/sealing film forming process S 240  are provided, but different therefrom in that an evaporation mask  510  is used. A mask portion of the evaporation mask  510  spreads from the peripheral circuit area  340  to a portion entering the display area  320 . For that reason, the light emitting organic layer  358  formed in the deposition process S 232  is formed to fall within the display area  320 . Also, because it is conceivable that the mask portion of the evaporation mask  510  comes in contact with the display area  320  together with the peripheral circuit area  340 , there is a need to consider a foreign matter  511  transferred in the display area  320  in addition to the foreign matter  411  transferred in the peripheral circuit area  340 . Taking the foreign matter  511  into account, in the cathode/sealing film forming process S 240 , the foreign matter  511  is also transferred in the display area  320  in addition to the peripheral circuit area  340 , as a result of which a portion where the sealing film  354  is not appropriately formed appears. Therefore, that portion may form an entry route of moisture. As described with reference to  FIG. 6 , the moisture entry route from the peripheral circuit area  340  can prevent the moisture from entering the display area  320  due to the existence of the blocking area  330 . However, the entry route of the moisture in the display area  320  leads to the deterioration of the light emitting organic layer  358  as it is, and causes the display failure. 
       FIG. 8  is a diagram illustrating a light emitting organic layer forming process and a cathode/sealing film forming process of a TFT substrate according to a comparative example 2. The light emitting organic layer forming process and the cathode/sealing film forming process of the comparative example 2 are identical with those in  FIG. 6  in that a mask loading process S 331 , a deposition process S 332 , and a cathode/sealing film forming process S 340  are provided, but different therefrom in that an evaporation mask  610  is used. A mask portion of the evaporation mask  610  used in the comparative example 2 has a width fixed in the peripheral circuit area  340 . For that reason, the light emitting organic layer  358  formed in the deposition process S 332  is formed to spread to the peripheral circuit area  340  beyond the blocking area  330 . Because it is conceivable that the mask portion of the evaporation mask  610  comes in contact with only the peripheral circuit area  340  as in  FIG. 6 , only the foreign matter  411  is considered as in  FIG. 6 . When the foreign matter  411  adheres to the peripheral circuit area  340 , the sealing film  354  is not appropriately formed in the peripheral circuit area  340  in the cathode/sealing film forming process S 340 , and this portion may form the entry route of the moisture. In this example, because the light emitting organic layer  358  is formed beyond the blocking area  330 , if the moisture enters from the moisture entry route of the peripheral circuit area  340 , the moisture is not blocked in the blocking area  330 , and deteriorates the light emitting organic layer  358  of the display area  320  through the light emitting organic layer  358 , thus causing the display failure. 
     As has been described above, in the above-mentioned embodiment, the blocking area  330  of the TFT substrate  300  has the first blocking area  331  and the second blocking area  332 . As a result, even if the moisture entry route is generated in the peripheral circuit area  340 , the moisture can be prevented from entering the display area  320 . Also, in the light emitting organic layer forming process causing the moisture entry route, the foreign matter can be prevented from being transferred from the evaporation mask to the display area  320 . For that reason, the sealing film  354  of the display area  320  can be appropriately formed, and the moisture can be prevented from entering the display area  320 . Therefore, the organic EL display device according to this embodiment can suppress the display failure due to the moisture entry of the display area from the outside periphery, and maintain the quality for a long period. 
     The above-mentioned embodiment can be applied to a light-emitting element display device using the organic light emitting material. 
     While there have been described what are at present considered to be certain embodiments of the invention, it will be understood that various modifications may be made thereto, and it is intended that the appended claim cover all such modifications as fall within the true spirit and scope of the invention.