JP2009162894A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device which does not cause short-circuiting defection even when a liquid crystal element part of the liquid crystal display device of connecting a counter electrode formed on a second electrode substrate with a connection circuit substrate by using a silver paste is miniaturized. <P>SOLUTION: In the liquid crystal display device, a liquid crystal display element is formed by enclosing liquid crystal between a first electrode substrate having a plurality of pixel electrodes and the second electrode substrate having the counter electrode opposite to the first electrode substrate, the liquid crystal display element is provided with a hood part extended to the outer side than the edge surface of the first electrode substrate on one side of the second electrode substrate, and a terminal electrode disposed on the hood part and a wiring pad of the connection circuit substrate are electrically connected with the conductive adhesive. Therein, a conductive pattern part is not formed in the neighborhood of a conductive adhesive coating where at least the terminal electrode connected with the counter electrode of the second electrode substrate, of the first electrode substrate is connected with the wiring pad of the connection circuit substrate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device.

  A general liquid crystal display element includes a second electrode substrate (for example, a glass substrate) having a transparent electrode formed on the surface thereof, and a first electrode substrate (for example, a transparent glass substrate, silicon) having a pixel electrode formed on the surface corresponding thereto. A substrate or an SOI substrate) is bonded together in a predetermined positional relationship, and liquid crystal is injected between the pair of substrates, and then sealed. In the liquid crystal display device, the liquid crystal display element is mounted on a circuit board (or a connection circuit board), and various displays are performed by applying a potential difference between the pixel electrode and the counter electrode to control the orientation of the liquid crystal.

  The potential supply to the pixel electrode of the liquid crystal display device is realized by electrically connecting the first electrode substrate and the electrode pad on the circuit substrate by wire bonding. On the other hand, the transparent electrode formed on the second electrode substrate facing the first electrode substrate was connected to the counter electrode by applying a conductive adhesive such as silver paste between the second electrode substrate and the circuit board. The terminal electrode (or integrally formed) and the electrode pad on the circuit board are electrically connected. (For example, Patent Document 1)

2 and 3 are a cross-sectional view (AA in FIG. 3) and a top view of the liquid crystal display device according to Patent Document 1. FIG. 2 and 3, reference numeral 10 denotes a liquid crystal display device. The liquid crystal display device 10 is an LCOS liquid crystal display device using a silicon element substrate as a first electrode substrate.
In FIG. 3, the liquid crystal display device 10 has a three-layer configuration of a first electrode substrate 1, a second electrode substrate 2, and an FPC 7. The FPC 7 is provided with a display area 7A and a connection area 7B, and a wiring pattern 7a for connecting a liquid crystal display element to be described later and an external circuit is provided on the surface thereof. Further, the first electrode substrate 1 and the second electrode substrate 2 are stacked in the display area 7A of the FPC 7, but are arranged slightly shifted from each other. The flanges 1A and 2A are formed so as to protrude outward from the end face of the electrode substrate.

  The first electrode substrate 1 is a silicon element substrate constituting a plurality of pixel switches. A reflective electrode 1a made of a reflective metal such as an aluminum film connected to the pixel switches and silicon oxide SiOx (X = 1 to 2). Is provided with an inorganic alignment film 1b obtained by oblique deposition. And the terminal electrode 1c connected to the pixel switch is provided in the collar part 1A of the 1st electrode substrate 1 as an external connection terminal. The second electrode substrate 2 is a glass substrate, and includes an opposing electrode 2a that is a transparent electrode film and an inorganic alignment film 2b on which silicon oxide SiOx (X = 1 to 2) is obliquely deposited. And the terminal electrode 2c connected to the counter electrode 2a is provided in the collar part 2A of the 2nd electrode substrate 2 as an external connection terminal. Furthermore, the FPC 7 is provided with wiring pads 7 c and 7 b connected to the wiring pattern 7 a as connection terminals for the first electrode substrate 1 and the second electrode substrate 2.

  A cell is formed by bonding the first electrode substrate 1 and the second electrode substrate 2 with a seal member 4, and a liquid crystal 3 is sealed in the cell to form a liquid crystal display element 5. Then, after the liquid crystal display element 5 is integrated by adhering the back surface of the first electrode substrate 1 to the upper surface of the FPC 7 that is the connection circuit substrate, the terminal electrode 2c of the second electrode substrate 2 and the wiring pad 7b of the FPC 7 Are electrically connected by a conductive adhesive 8, and the periphery of the conductive adhesive 8 is coated with a protective resin 9. A predetermined gap H is provided between the outer periphery of the protective resin 9 and the end face of the first electrode substrate 1. The conductive adhesive 8 is a mixture of silver particles 8a in an epoxy resin 8b serving as an adhesive, and the protective resin 9 is a thermosetting or ultraviolet curable epoxy resin or a silicone resin. . Among them, it is preferable to use a silicone resin that has a relatively low stress on the substrate or the like and can keep the thickness of the liquid crystal stable. Silicone resin is most suitable as a protective resin because it mixes a silicone coupling agent that functions as a surface active agent to improve wettability and penetrability to contact objects. The terminal electrode 1c of the first electrode substrate 1 and the wiring pad 7c of the FPC 7 are wire-bonded by a wire 11 such as a gold wire or an aluminum wire, and the periphery of the wire 11 is used as a protective resin 9 to form a silicone resin. Is provided. The silicone resin is mixed with a pigment that absorbs visible light, and also serves as a light blocking body for preventing light from entering the wiring pad portion. For example, it coats with black silicone resin.

  According to the above configuration, the protective resin 9 securely protects the periphery of the conductive adhesive 8 but does not contact the side surface of the first electrode substrate 1, so that the protective resin 9 expands and contracts due to the ambient temperature and humidity. However, high accuracy of display can be maintained without applying stress to the first electrode substrate 1. That's it.

JP 2007-249014 A

  A small liquid crystal display device, particularly a liquid crystal display device used for a mobile phone, has been required to have an outer shape as small as possible and a display area large. As shown in FIG. 2, in the prior art, the flange portion 2 </ b> A of the second electrode substrate 2 is made large (1 to 1.5 mm) so that the conductive paste 8 and the protective resin 9 do not contact the first electrode substrate 1. For this reason, the outer shape of the liquid crystal display element constituted by the first electrode substrate and the second electrode substrate has become large.

  The size can be reduced by making the flange portion 2A as small as possible and eliminating the protective resin 9, but the silver paste 8 as the conductive adhesive and the reflective electrode 1b formed on the first electrode substrate 1 (or transparent) An electrode (not shown) may be short-circuited. FIG. 4 is an enlarged top view of a part of the silicon element substrate according to the prior art. Since the TEG 12 for inspecting the silicon element substrate 1 is formed on the outer periphery of the silicon element substrate 1, the conductive paste 8 is the first paste. If it adheres to the outer periphery (staggered hatched portion) of one electrode substrate 1, a short circuit may occur. Reference numeral 4 'denotes a seal region.

  The object of the present invention has been made in view of the above problems, and even if the liquid crystal display element portion of the liquid crystal display device in which the counter electrode formed on the second electrode substrate and the connection circuit substrate are connected with the silver paste is downsized, the shoot is defective. It is to prevent the occurrence.

  A liquid crystal display element is formed by sealing liquid crystal between a first electrode substrate having a plurality of pixel electrodes and a second electrode substrate having a counter electrode facing the first electrode substrate, and the liquid crystal display element is a second electrode. A liquid crystal display device in which a flange extending outward from the end surface of the first electrode substrate is provided on one side of the substrate, and the terminal electrode provided on the flange and the wiring pad of the connection circuit substrate are electrically connected by a conductive adhesive The conductive pattern portion is not formed in the vicinity of the conductive adhesive applied to connect the terminal electrode connected to the counter electrode of the second electrode substrate and the wiring pad of the connection circuit substrate at least on the first electrode substrate. A liquid crystal display device is assumed.

  A liquid crystal display device in which the conductive adhesive is a silver paste is used.

  A liquid crystal display device in which the first electrode substrate is a silicon element substrate on which pixel switches are formed.

  According to the present invention, even if the terminal electrode formed on the second electrode substrate and the pad formed on the connection circuit substrate are connected using the fluid silver paste, there is no short circuit with the first electrode substrate. .

  In particular, it is effective for miniaturization when a silicon element substrate (SOI substrate) is used for the first electrode substrate.

  A liquid crystal display element is formed by sealing liquid crystal between a first electrode substrate having a plurality of pixel electrodes and a second electrode substrate having a counter electrode facing the first electrode substrate, and the liquid crystal display element is a second electrode. A liquid crystal display device in which a flange extending outward from the end surface of the first electrode substrate is provided on one side of the substrate, and the terminal electrode provided on the flange and the wiring pad of the connection circuit substrate are electrically connected by a conductive adhesive The conductive pattern portion is not formed in the vicinity of the conductive adhesive applied to connect the terminal electrode connected to the counter electrode of the second electrode substrate and the wiring pad of the connection circuit substrate at least on the first electrode substrate. A liquid crystal display device is assumed.

  FIG. 1 is a top view (A) and a cross-sectional view BB of a liquid crystal display device according to the present invention. The liquid crystal 3 is sealed between the first electrode substrate 21 having a plurality of pixel electrodes and the second electrode substrate 22 having the counter electrode 22a facing the first electrode substrate 21 to form a liquid crystal display element, and the liquid crystal display The element is provided with a flange 22A projecting outward from the end surface 21B of the first electrode substrate 21 on one side of the second electrode substrate 22, and a terminal electrode 22c provided on the flange 22A and a wiring pad 7b of the connection circuit substrate 7 are provided. The liquid crystal display device is electrically connected by a conductive adhesive 8.

  In the vicinity of the application of a conductive adhesive for connecting at least the terminal electrode 22c of the first electrode substrate 21 connected to the counter electrode 22a of the second electrode substrate and the wiring pad 7b of the connection circuit substrate 7 (in the figure, staggered hatching) Part) 21A is not formed with a conductive pattern part. That is, the transparent electrode and the TEG of the conventional example are not formed in the staggered hatching portion, so that even if the silver paste 8 that is a conductive adhesive and fluid is applied, the first electrode substrate 21 is not short-circuited. In the figure, the zigzag hatching portion is widely formed as the conductive adhesive application vicinity 21A, but it is needless to say that it may be limited not to the entire zigzag hatching portion but to the vicinity of the silver paste application if a short circuit can be prevented.

  By setting it as the structure of this invention, 22 A of collar parts can be 0.1 mm, and an external shape can be made small. As an effect of downsizing according to the present invention, for example, when a 2.5-inch liquid crystal display element is manufactured from a 6-inch mother substrate, the conventional number of pieces is 250, whereas the liquid crystal display element structure of the present invention is According to the number of 290. This is an increase of 16%, which means that it can be manufactured at a lower cost.

The top view (A) and BB sectional drawing (B) of the liquid crystal display device by this invention Sectional view of liquid crystal display device (AA in FIG. 3) Top view of liquid crystal display device An enlarged top view of a part of a silicon element substrate according to the prior art

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st electrode board | substrate 1a Reflective electrode 1b Inorganic alignment film 1c Terminal electrode 1A A collar part 2 2nd electrode board | substrate 2a Opposite electrode 2b Inorganic alignment film 2c Terminal electrode 2A Acupuncture part 3 Liquid crystal 4 Seal member 4 'Seal area | region 5 Liquid crystal display element 7 FPC
7a Wiring pattern 7b Wiring pad 7c Wiring pad 7A Display area 7B Connection area 8 Conductive adhesive (silver paste)
8a Silver particles 8b Epoxy resin 9 Protective resin 10 Liquid crystal display device 11 Wire 12 TEG
21 First electrode substrate 21A Near conductive adhesive application 21B End face 22 Second electrode substrate 22a Counter electrode 22c Terminal electrode 22A

Claims (3)

A liquid crystal display element is formed by sealing liquid crystal between a first electrode substrate having a plurality of pixel electrodes and a second electrode substrate having a counter electrode facing the first electrode substrate, and the liquid crystal display element is a second electrode. A liquid crystal display device in which a flange extending outward from the end surface of the first electrode substrate is provided on one side of the substrate, and the terminal electrode provided on the flange and the wiring pad of the connection circuit substrate are electrically connected by a conductive adhesive The conductive pattern portion is not formed in the vicinity of the conductive adhesive applied to connect the terminal electrode connected to the counter electrode of the second electrode substrate and the wiring pad of the connection circuit substrate at least on the first electrode substrate. A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1, wherein the conductive adhesive is a silver paste. 3. The liquid crystal display device according to claim 1, wherein the first electrode substrate is a silicon element substrate on which a pixel switch is formed.

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