JP2006147192A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain an adverse effect of moisture on an organic EL element, and alleviate damage on a circuit in an application region of an element substrate. <P>SOLUTION: A contact surface area of a sealing material 7 can be enlarged by providing a groove 17 at a laminated part of a sealing substrate 13. As a result, a sealing effect is improved, and infiltration of moisture from outside can be restrained. Further, since the groove 17 is formed at a position corresponding to a drive circuit 1, a spacer 11 in the sealing material 7 can prevent the drive circuit 1 from direct pressure, so that damage on the drive circuit 1 can be restrained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sealing structure for sealing an element substrate and a sealing substrate of a display device with a sealing material.

  In recent years, an EL display device using an LCD or an electroluminescence (hereinafter referred to as “EL”) element has attracted attention as a display device that replaces the CRT.

  For example, in an organic EL display panel, a plurality of pixels each including an organic EL element on an element substrate and a thin film transistor (hereinafter referred to as “TFT”) for driving the organic EL element are arranged in a matrix. The display region is formed by the plurality of pixels. Since the organic EL element has a characteristic that it is vulnerable to moisture, a sealing structure has been proposed in which moisture is prevented from entering by covering the element substrate with a metal cap or a sealing substrate coated with a desiccant.

In the case of a sealing structure using a sealing substrate, an element substrate on which an organic EL element is formed and the sealing substrate are coated with a sealing material including a spacer on the periphery of both substrates, and both substrates are formed by flat plates. A load was applied to and bonded together.
JP-A-12-127420

  Here, the organic layer of the organic EL element and the liquid crystal material of the LCD have a drawback that the sealing material sealing the peripheral portion of the element substrate and the peripheral portion of the sealing substrate is deteriorated by moisture entering from the interface between the two substrates. Was. Therefore, there is a problem that it is desired to improve the sealing performance of the interface.

  In addition, organic EL panels and LCD panels have a drive circuit of a predetermined size for driving the display element in the bonding area of the peripheral portion of the element substrate and the sealing substrate on the element substrate side. When applying this pressure, there is a problem that the drive circuit is damaged by the spacer in the sealing material.

  Therefore, the present invention provides an element substrate provided with a plurality of display elements, a sealing substrate disposed opposite to the element substrate at a predetermined interval, a peripheral portion of the element substrate, and a peripheral portion of the sealing substrate. And a sealing material that seals the internal space formed by the bonding, and in a bonding region of the peripheral portion of the sealing substrate that is bonded to the peripheral portion of the element substrate, a predetermined depth and a predetermined amount A groove with a width was provided.

  In the present invention, the groove is formed in a bonding region of all sides of the peripheral portion of the sealing substrate that is joined to the peripheral portion of the element substrate. By providing the groove in this manner, the surface area where the sealing substrate and the sealing material are in contact with each other can be increased. As a result, the sealing effect can be improved.

Furthermore, according to the present invention, a circuit for driving the display element is formed corresponding to the groove in the bonding region of the element substrate and the sealing substrate on the element substrate side. By providing the groove, it is possible to prevent the spacer in the sealing material from directly applying pressure to the circuit, and to suppress damage to the circuit.

  In the present invention, in the bonding region between the element substrate and the sealing substrate, by providing a groove in the sealing substrate, an area where the sealing substrate and the sealing material are in contact with each other can be increased. As a result, the sealing effect is improved and the intrusion of moisture from the outside can be suppressed. Further, it is possible to prevent the spacer in the sealing material from directly applying pressure to the drive circuit by the groove, and damage to the drive circuit can be suppressed.

Hereinafter, embodiments of a display device of the present invention will be described based on the drawings in the case of an organic EL panel.
<Example>
FIG. 1 shows the overall configuration of an organic EL panel in a display device according to the present invention.
The organic EL panel of the present invention includes an element substrate 3 provided with an organic EL element, and a sealing substrate 13 provided so as to face the element substrate 3, and the peripheral portions of both the substrates 3 and 13 are provided. Bonded with sealant 7. Further, the side surfaces of the bonded element substrate 3 and sealing substrate 13 are covered with a protective resin 11. By doing so, it is possible to further suppress the intrusion of moisture.

  First, FIG. 2 shows a plan view of the element substrate as viewed from the display element formation surface (in FIG. 1, a plan view of the element substrate 3 including the display region from the sealing substrate 13 side). The element substrate 3 will be described. To do.

  A display area 5 in which a plurality of pixels 19 are arranged in a matrix on the surface of the element substrate 3, and a peripheral drive that drives a thin film transistor and an organic EL element formed in the display area 5 in the periphery of the display area 5 A circuit (horizontal driver, vertical driver) 1 is provided.

  Further, the configuration of one pixel 19 is shown in the ejection portion of FIG. The pixel 19 includes an organic EL element (EL), a switching TFT (TR1) that drives the organic EL element (EL), and a driving TFT (TR2). The switching TFT (TR1) is turned on by the scanning signal Gm from the vertical driver, and the video signal flowing in the signal line signal is charged to the holding capacitor (SC). PVdd current flows to the EL element (EL), and the EL element (EL) emits light.

  Next, the organic EL element will be described. The organic EL element includes an anode made of a transparent electrode such as ITO (Indium Tin Oxide), a first hole transport layer made of MTDATA (4,4,4-tris (3-methylphenylphenylamino) triphenylanine), TPD (4,4-bis). A hole transport layer comprising a second hole transport layer comprising (3-methylphenylphenylamino) biphenyl), a light emitting layer comprising Bebq2 (10-benzo [h] quinolinol-beryllium complex) containing a quinacridone derivative, and an electron comprising Bebq2. This is a structure in which a transport layer, a cathode made of magnesium / indium alloy or aluminum, or an aluminum alloy are laminated in this order.

  In the organic EL element, holes injected from the anode and electrons injected from the cathode are recombined inside the light emitting layer, and excitons are generated by exciting organic molecules forming the light emitting layer. Light is emitted from the light emitting layer in the process of radiation deactivation of the excitons, and this light is emitted from the transparent anode through the transparent insulating substrate to emit light.

  A protective film is formed on the organic EL element in order to protect the organic EL element from moisture and the like. The protective film may be an inorganic layer made of an inorganic material, or a composite layer in which an organic layer made of an organic material and an inorganic layer are laminated.

  Next, the sealing substrate 13 will be described. The sealing substrate 13 is provided so as to face the element substrate 5, and includes a recess 29 formed corresponding to the display region 5 of the element substrate 3, and has a ring shape around each side of the substrate. A groove 17 is formed. The recess 29 is coated with the desiccant 15 on the inner surface.

Based on FIG. 3, the formation method of the recessed part 29 and the groove | channel 17 of the sealing substrate 13 is shown.
(A) A resist substrate 21 is covered with a sealing substrate (eg, glass or quartz) 13 (thickness is about 0.7 mm) covered with a metal film 23 (eg, chromium) so that only the peripheral portion of the sealing substrate is covered. (B) The metal film 23 to be disposed is etched, and then the resist mask 21 is removed. (C) The glass 29 is etched with an etchant such as hydrofluoric acid to form the recesses 29. Since the concave portion 29 is also etched when forming the groove portion in a later step, the etching is performed at a depth in consideration of etching the groove portion. The area of the recess 29 is the same as or larger than that of the display area 5 of the element substrate 3. (D) Covers the convex portion (width is about 3 mm, the later bonding region) of the peripheral portion of the sealing substrate 13, and the substantially central portion of the convex portion has the same width as the drive circuit 1 (about 1.5 mm). (E) The metal film 23 is etched and then the resist mask 21 is removed. (F) The glass is etched with hydrofluoric acid using the etched metal film as a mask. Etching is performed to form a recess 29 (depth of about 0.3 mm by two etchings) and a groove (depth of 40 μm). (G) The metal film 23 is removed.

  By performing the above process, the concave portion 29 and the groove 17 of the sealing substrate 3 can be formed.

  Next, FIG. 4 shows a perspective view of the sealing substrate cut so as to remove one side of the sealing substrate. Grooves 17 at the periphery of the sealing substrate 13 are formed on each side. The groove 17 increases the area of the interface between the sealing material and the sealing substrate, increases the sealing effect, and suppresses intrusion of moisture from the outside. If a sufficient sealing effect is obtained, the element substrate drive circuit (horizontal driver / vertical driver) 1 can be used as a sealing substrate without providing the grooves 17 so as to surround all sides as shown in FIG. When the four sides are formed, the grooves 17 may be provided only at positions corresponding to the four sides. That is, as shown in FIG. 6, at least a part of the groove 17 surrounding all sides may be separated. If the drive circuit 1 is formed on only two sides as shown in FIG. 2, the groove 17 may be formed on only two sides in FIG. 6 to suppress the ingress of moisture. Therefore, a groove may be formed on a side where no circuit is formed.

Further, the groove 17 may have a plurality of grooves 17 on one side in order to enhance the sealing effect. Next, a process of bonding the element substrate 3 and the sealing substrate 13 will be described with reference to FIG. In an inert gas atmosphere such as N ₂ gas, the sealing substrate 13 is placed on the quartz plate 25 and a sealing material is applied to the peripheral bonding region, while the element substrate 3 is located above the quartz plate 25. Are placed on a metal suction plate 27 opposite to each other by vacuum suction. Then, the EL element formed on the main surface of the element substrate 3 and the desiccant 15 formed on the main surface of the sealing substrate 13 are arranged to face each other. Next, the suction plate is lowered by the moving mechanism to bring the sealing substrate 13 and the element substrate 3 into close contact. Thereafter, UV irradiation is performed on the sealing material 7 from the back surface of the quartz plate 25 through the quartz plate 25 and the sealing substrate 13 by the UV irradiation device, and the sealing material 7 is cured, whereby the element substrate 3 and the sealing substrate 13 are cured. Is glued.

  Next, FIG. 8 shows a layout of the element substrate 3, the sealing substrate 13, and the sealing material 7. As shown in FIG.

  The groove portion 17 of the sealing substrate 13 will be described. The depth of the groove 17 of the sealing substrate 13 is not less than the sum of the diameter of the sphere of the spacer 11 (the material is aluminum or the like and the diameter is about 10 μm) and the thickness of the circuit (about 30 μm). For example, it is about 40 μm.

  Further, as shown in FIG. 8, the groove 17 of the sealing substrate 13 is formed above the drive circuit 1, and thus has a groove width that is greater than or equal to the width of the drive circuit 1 (about 1.5 mm). By adopting such a configuration, when the element substrate 3 and the sealing substrate 13 are brought into close contact with each other, the spacer 9 enters the groove portion 17 and damage to the drive circuit 1 due to the spacer 9 can be suppressed.

  As long as the shape of the groove 17 can suppress moisture intrusion and suppress damage to the drive circuit 1, even if the cross-sectional shape is not V-shaped, the U-shape shown in FIG. A U shape is also acceptable. By forming such a shape, the spacer 9 can easily enter the groove portion 17 and damage due to the spacer 9 can be suppressed. The grooves 17 shown in FIGS. 9 and 10 are arranged to face each other so as to cover the entire drive circuit 1. However, if the spacer 9 can be inserted into the groove portion 17, the grooves 17 are formed in the drive circuit 1. It may be formed so as to face only a part without covering all.

  After the element substrate 3 and the sealing substrate 13 are in close contact with each other, the side surfaces of the element substrate 3, the sealing substrate 13 and the sealing material 7 are covered with a protective resin 11 as shown in FIG. This protective resin 11 is formed of, for example, an epoxy resin, and makes the sealing with the sealing material 7 more complete. The protective resin 11 may cover not only the side surface but the entire surface.

  With the above configuration, the sealing effect due to the groove formation can be further improved, and damage to the organic EL element due to moisture from the outside can be suppressed.

  In the above-described embodiment, the drive circuit (horizontal driver / vertical driver) has been described in which both the horizontal driver and the vertical driver are arranged corresponding to the grooves. Only one of the vertical drivers may be used.

  In the above-described embodiment, the organic EL panel including the organic EL element has been described. However, the present application is not limited thereto, and the organic EL panel can be used for a display device such as an LCD or a VFD. The same effect as in the case of.

1 is a cross-sectional structure diagram of an organic EL panel according to the present invention. It is a block diagram of the element substrate surface. It is a figure showing the formation method of the recessed part and groove part of the sealing substrate which concern on this invention. It is a perspective view of the cut | disconnected sealing substrate which concerns on this invention. It is a top view of the sealing substrate in which the groove | channel concerning this invention was formed. It is a top view of the sealing substrate in which the groove | channel concerning this invention was formed. It is a figure of the bonding process of an organic electroluminescent panel. It is sectional drawing of the sealing substrate whose groove part which concerns on this invention is V shape. It is sectional drawing of the sealing substrate whose groove part which concerns on this invention is U shape. It is sectional drawing of the sealing substrate whose groove part which concerns on this invention is U-shaped.

Explanation of symbols

1 drive circuit (horizontal driver / vertical driver), 3 element substrate, 5 display area,
7 sealing material, 9 spacer, 11 protective resin, 13 sealing substrate,
15 desiccant, 17 grooves, 19 pixels, 21 resist mask, 23 metal mask,
25 quartz plate, 27 metal suction plate, 29 recess

Claims (3)

An element substrate provided with a plurality of display elements;
A sealing substrate that faces the element substrate and is disposed at a predetermined interval, a seal that joins a peripheral portion of the element substrate and a peripheral portion of the sealing substrate, and seals an internal space formed by the joining Material,
Including
A display device, wherein a groove having a predetermined depth and a predetermined width is provided in a bonding region of the peripheral portion of the sealing substrate to be bonded to the peripheral portion of the element substrate. The display device according to claim 1, wherein the groove is formed in a bonding region of all sides of the peripheral portion of the sealing substrate that is bonded to the peripheral portion of the element substrate. 3. The circuit for driving the display element is formed on the element substrate so as to correspond to the groove in a bonding region of the element substrate and the sealing substrate. The display device described in 1.

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