JP2008026771A - Electrooptical device and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce electric resistance of a connection part electrically connecting e.g. a TFT array substrate and a counter substrate to each other. <P>SOLUTION: It is not necessary to make a complicated connection structure electrically connecting the TFT array substrate 10 and the counter substrate 20 to each other and the construction of a conductive part such as a wiring line formed in each of the TFT array substrate 10 and the counter substrate 20 can be made simple. According to such a liquid crystal device 1, connection resistance in upper and lower conduction terminals electrically connecting the TFT array substrate 10 and the counter substrate 20 to each other can be eliminated and reduction of a conduction defect is made possible. Miniaturization of the liquid crystal device 1 is also made possible since an FPC 500 is interposed between the TFT array substrate 10 and the counter substrate 20 according to the liquid crystal device 1 for an embodiment. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electro-optical device such as a liquid crystal panel driven by various signals supplied through connection means such as an FPC (Flexible Printed Circuit), and an electronic device such as a projector provided with such a liquid crystal panel. Related to the technical field.

  In this type of electro-optical device, various signals including an image signal and power and power are supplied from an external circuit via connection means such as an FPC. An example of a technique capable of reducing the size of a liquid crystal display device which is an example of such an electro-optical device is disclosed in Patent Document 1.

  In the liquid crystal display device, the terminal portion of the FPC is usually electrically connected to the terminal portion provided on the element substrate such as a TFT array substrate. The wiring formed on each of the element substrate and the counter substrate disposed opposite to the element substrate is connected to each other by a vertical conduction terminal, and the wiring and the vertical conduction terminal are connected to the counter substrate from a terminal portion provided on the element substrate. A power source and various signals are supplied via the. More specifically, a potential such as a counter electrode potential is supplied to the counter electrode provided on the counter substrate.

JP 2003-107519 A

  In this type of electro-optical device, as described in Patent Document 1, there is a demand for reducing the size of the device. In addition, the display performance of an electro-optical device such as a liquid crystal display device is deteriorated due to poor conduction between the element substrate and the counter substrate that occurs when the element substrate and the counter substrate are bonded together and an increase in connection resistance at the connection portion. There is a risk that problems will become apparent. There is also a demand for simplifying the device configuration by reducing the number of wires routed in the device.

  However, Patent Document 1 does not describe in detail the electrical connection configuration between the element substrate and the counter substrate.

  Therefore, the present invention has been made in view of the above-mentioned problems and the like. For example, the connection substrate and the connection substrate for electrically connecting the counter substrate and the element substrate included in the liquid crystal device are reduced, and the counter substrate is reduced. It is an object of the present invention to provide an electro-optical device such as a liquid crystal device in which the number of wirings provided in the device is reduced, and an electronic apparatus such as a projector including such an electro-optical device.

  In order to solve the above problems, an electro-optical device according to the present invention includes an element substrate having a pixel electrode formed on each of a plurality of pixels constituting a display area, and the pixel electrode as viewed from the element substrate. A counter substrate arranged to face the element substrate on the other side, an external substrate sandwiched between the element substrate and the counter substrate in a region outside the display region, and the element substrate in the external substrate A first connection terminal formed on a surface facing side, a second connection terminal formed on a surface of the external substrate facing the counter substrate, and provided on the element substrate in the outer region. A third connection terminal electrically connected to the first connection terminal, and a fourth connection terminal provided on the counter substrate in the outer region and electrically connected to the second connection terminal. And Obtain.

  According to the electro-optical device of the present invention, for example, in a display region on an element substrate on which a pixel switching element such as a thin film transistor (TFT) is formed, more specifically, in a display region where an image is displayed by a plurality of pixels. A pixel electrode for applying a driving voltage to an electro-optical material such as liquid crystal is formed. For example, the counter substrate and the element substrate sandwich an electro-optical material such as liquid crystal. The external substrate is a connection means such as an FPC that electrically connects the external circuit and the electro-optical device, in the region outside the display region, more specifically, at each end of the element substrate and the counter substrate, It is sandwiched between these substrates.

  The first connection terminal is formed on a surface of the external substrate that faces the element substrate. More specifically, the external substrate and the element substrate are formed in a region where the external substrate and the counter substrate overlap each other outside the display region in a state where the external substrate is sandwiched between the element substrate and the counter substrate. Similarly to the first connection terminal, the second connection terminal is formed on the surface of the external substrate facing the counter substrate outside the display area. Therefore, each of the first connection terminal and the second connection terminal is formed on the surfaces of the external substrate facing each other. The first connection terminal and the second connection terminal are supplied with power or various signals through wiring formed on an external substrate such as an FPC.

  The third connection terminal is provided on the element substrate in a region outside the display region, and is electrically connected to the first connection terminal in a state where the external substrate is sandwiched between the element substrate and the counter substrate. More specifically, the first connection terminal and the third connection terminal are in contact with each other and are electrically connected to each other in a state where the external substrate is sandwiched between the element substrate and the counter substrate.

  Similar to the third connection terminal, the fourth connection terminal is provided on the counter substrate in a region outside the display region, and is electrically connected to the second connection terminal. More specifically, the second connection terminal and the fourth connection terminal are in contact with each other and are electrically connected to each other in a state where the external substrate is sandwiched between the element substrate and the counter substrate.

  According to such an electro-optical device, the first connection terminal and the third connection terminal are electrically connected to each other, and the second connection terminal and the fourth connection terminal are electrically connected to each other. The element substrate and the counter substrate can be electrically connected to each other without providing the vertical conduction terminals. Therefore, it is not necessary to create a complicated connection structure for electrically connecting the element substrate and the counter substrate to each other, and the configuration of the conductive portions such as wirings formed on the element substrate and the counter substrate can be simplified. it can. According to such an electro-optical device, it is possible to suppress connection resistance and reduce conduction failure in a connection portion that electrically connects the element substrate and the counter substrate.

  In addition, since an external circuit is sandwiched between the element substrate and the counter substrate, the electro-optical device can be downsized.

  In one aspect of the electro-optical device according to the invention, the fourth connection terminal is electrically connected to a counter electrode formed on the counter substrate so as to face the pixel electrode, and the second connection The terminal supplies a counter electrode potential to the counter electrode via the fourth connection terminal, the third connection terminal is electrically connected to the pixel electrode, and the first connection terminal is connected to the first connection terminal. The image signal may be supplied to the three connection terminals.

  According to this aspect, the counter electrode potential can be supplied to the counter electrode directly or indirectly via the second connection terminal and the fourth connection terminal. Similarly, the image signal supplied from the image signal supply circuit to the external substrate can be supplied to the third connection terminal via the first connection terminal. For example, the image signal is supplied to each pixel portion via various wirings and driving circuits formed on the element substrate, and a potential is supplied to the pixel electrode in accordance with the image signal. As a result, a driving voltage is applied to an electro-optical material such as liquid crystal interposed between the pixel electrode and the counter electrode, and an image is displayed in the display area.

  In this aspect, the fourth connection terminal may be an extension portion in which the counter electrode extends to the outer region.

  According to this aspect, the counter electrode potential is supplied from the second connection terminal to the counter electrode without passing through the wiring such as the counter electrode potential line. Therefore, it is not necessary to provide the counter electrode potential line on the element substrate, and the number of wirings provided on the element substrate can be reduced.

  In another aspect of the electro-optical device according to the present invention, the third connection includes the first recess formed by partially digging a surface of the element substrate facing the external substrate in the outer region. The terminal may be formed in the first recess.

  According to this aspect, even when the thickness of the external substrate, the first connection terminal, and the second connection terminal is thick, the first connection terminal is connected to the first recess so as to be in contact with the third connection terminal formed in the first recess. Can be matched. Therefore, it is possible to sandwich the external substrate between these element substrates and the counter substrate while maintaining the gap dimension.

  In another aspect of the electro-optical device according to the invention, the fourth connection is provided with a second recess formed by partially digging a surface of the counter substrate facing the external substrate in the outer region. The terminal may be formed in the second recess.

According to this aspect, as in the case where the second concave portion described above is provided, it is possible to sandwich the external substrate between these elements while maintaining the gap dimension between the element substrate and the counter substrate.
it can.

  In another aspect of the electro-optical device according to the present invention, in the outer region, the outer substrate is formed on a surface of the external substrate facing the element substrate, and is electrically connected to the second connection terminal. 5 connection terminals may be provided.

  According to this aspect, for example, the second connection terminal and the fifth connection terminal are electrically connected by the conductive portion provided so as to penetrate the external substrate. Therefore, a power supply or various signals can be supplied to the second connection terminal via the wiring provided on one surface of the external substrate on which the fifth connection terminal is formed.

  In order to solve the above problems, an electronic apparatus according to the present invention includes the above-described electro-optical device of the present invention.

  According to the electronic apparatus according to the present invention, since the electro-optical device according to the present invention described above is provided, a projection display device, a mobile phone, an electronic notebook, and a word processor capable of high-quality display with a simple configuration. Various electronic devices such as a viewfinder type or a monitor direct view type video tape recorder, a workstation, a videophone, a POS terminal, and a touch panel can be realized. In addition, as an electronic apparatus according to the present invention, for example, an electrophoretic device such as electronic paper can be realized.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

  Hereinafter, embodiments of an electro-optical device and an electronic apparatus according to the present invention will be described with reference to the drawings.

<1: Electro-optical device>
First, an embodiment of an electro-optical device according to the invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a plan view of the electro-optical device when the TFT array substrate is viewed from the counter substrate side together with the components formed thereon, and FIG. 2 is a cross-sectional view taken along the line II-II ′ of FIG. 3 is a cross-sectional view taken along the line III-III ′ of FIG. In the present embodiment, as an example of an electro-optical device, a TFT active matrix driving type liquid crystal device with a built-in driving circuit is taken as an example.

  1 to 3, in the liquid crystal device 1, the TFT array substrate 10 and the counter substrate 20 are disposed to face each other, and an FPC 500 that is an example of the “external substrate” of the electro-optical device according to the present invention is interposed between these substrates. Is pinched. A first connection terminal 201 is provided on the surface of the FPC 500 facing the TFT array substrate 10. A second connection terminal 202 is formed on the surface of the FPC 500 facing the counter substrate 20. A third connection terminal 103 a electrically connected to the first connection terminal 201 is formed outside the image display area 10 a on the surface of the TFT array substrate 10 facing the FPC 500. A fourth connection terminal 204 electrically connected to the second connection terminal 202 is formed on the surface of the counter substrate 20 facing the FPC 500.

  A liquid crystal layer 50 is sealed between the TFT array substrate 10 and the counter substrate 20, and the TFT array substrate 10 and the counter substrate 20 are positioned around a display region 10a that is a pixel region in which a plurality of pixel portions are provided. They are bonded to each other by a sealing material 52 provided in the sealing area.

  The sealing material 52 is made of, for example, an ultraviolet curable resin, a thermosetting resin, or the like for bonding the two substrates, and is applied on the TFT array substrate 10 in the manufacturing process and then cured by ultraviolet irradiation, heating, or the like. It is. In the sealing material 52, a gap material such as glass fiber or glass beads for dispersing the distance between the TFT array substrate 10 and the counter substrate 20 (inter-substrate gap) to a predetermined value is dispersed. The liquid crystal device 1 of this embodiment is small and suitable for performing enlarged display for a light valve of a projector.

  A light-shielding frame light-shielding film 53 that defines the frame area of the image display area 10a is provided on the counter substrate 20 side in parallel with the inside of the seal area where the sealing material 52 is disposed. However, part or all of the frame light shielding film 53 may be provided as a built-in light shielding film on the TFT array substrate 10 side. A peripheral area exists around the image display area 10a. In other words, particularly in the present embodiment, when viewed from the center of the TFT array substrate 10, a region farther than the frame light shielding film 53 (that is, an outer region) is defined as a peripheral region.

  In FIG. 2, on the TFT array substrate 10, an alignment film 16 is formed on the pixel electrode 9a after the pixel switching TFT, the scanning line, the data line and the like are formed. The TFT array substrate 10 is a transparent substrate such as a quartz substrate, a glass substrate, or a silicon substrate. A pixel electrode 9a is provided on the TFT array substrate 10, and an alignment film 16 that has been subjected to a predetermined alignment process such as a rubbing process is provided above the pixel electrode 9a. The pixel electrode 9a is made of a transparent conductive film such as an ITO (Indium Tin Oxide) film, and the alignment film 16 is made of an organic film such as a polyimide film.

  On the counter substrate 20, in addition to the counter electrode 21 provided over the entire surface, a lattice-shaped or striped light-shielding film 23, and an alignment film 22 is formed on the uppermost layer (lower side in the figure). Yes. The counter substrate 20 is also a transparent substrate like the TFT array substrate 10. The counter electrode 21 is made of a transparent conductive film such as an ITO film, for example. The alignment film 22 is made of an organic film such as a polyimide film.

  The liquid crystal layer 50 is made of, for example, a liquid crystal in which one or several types of nematic liquid crystals are mixed, and takes a predetermined alignment state by the alignment film in a state where an electric field from the pixel electrode 9a is not applied.

  During the operation of the liquid crystal device 1, the counter electrode potential is supplied to the counter electrode 21 through the second connection terminal 202 and the fourth connection terminal 204. The pixel electrode 9a is supplied with a pixel electrode potential in accordance with an image signal supplied via the first connection terminal 201 and the third connection terminal 103, and the liquid crystal orientation is controlled by a voltage corresponding to the potential difference between these electrodes. And a desired image is displayed in the image display area 10a.

  In the peripheral region of the TFT array substrate 10, the data line driving circuit 101 and a plurality of third connection terminals 103 are provided on one side of the TFT array substrate 10 in a region located outside the seal region where the sealing material 52 is disposed. It is provided along. The third connection terminal 103 is provided in a first recess 112 formed by partially dug the TFT array substrate 10. Therefore, in a state where the FPC 500 is sandwiched between the TFT array substrate 10 and the counter substrate 20, the first connection terminal 201 is fitted into the first recess 112, and the first connection terminal 201 and the third connection terminal 103 are in contact with each other. . Thereby, the 1st connecting terminal 201 and the 3rd connecting terminal 103 are electrically connected. Similarly, the fourth connection terminal 204 is provided in a second recess 212 formed by partially digging the counter substrate 20. Therefore, in a state where the FPC 500 is sandwiched between the TFT array substrate 10 and the counter substrate 20, the second connection terminal 202 is fitted into the second recess 212, and the second connection terminal 202 and the fourth connection terminal 204 are in contact with each other. . As a result, the second connection terminal 202 and the fourth connection terminal 204 are electrically connected.

  According to the first recess 112 and the second recess 212, the FPC 500 can be interposed between the substrates while maintaining the gap between the TFT array substrate 10 and the counter substrate 20. More specifically, the thicknesses of the first connection terminal 201, the second connection terminal 202, the third connection terminal 103, and the fourth connection terminal 204 are digged into the first recess 112 and the second recess 212 and fall within the dimensions. Therefore, the gap between the TFT array substrate 10 and the counter substrate 20 can be prevented from widening by the thickness of these terminals.

  An input terminal 502 that is an example of the “fifth connection terminal” of the present invention is provided at the end of the FPC 500 that is not sandwiched between the TFT array substrate 10 and the counter substrate 20. The input terminal 502 is electrically connected to the first connection terminal 201 and the second connection terminal 202 through the wiring 510. The input terminal 502 is electrically connected to an external circuit, and when the liquid crystal device 1 operates, various signals such as a power supply or an image signal are transmitted to the first connection terminal 201, the second connection terminal 202, the third connection terminal 103, and the fourth connection terminal 502. It is supplied to each of the TFT array substrate 10 and the counter substrate 20 via the connection terminal 204. Here, since the fourth connection terminal 204 is electrically connected to the counter electrode 21 via a wiring (not shown), the counter electrode potential is opposed to the counter via the second connection terminal 202 and the fourth connection terminal 204. It is supplied to the electrode 21. Therefore, the FPC 500 directly faces the counter substrate 20 side without providing a vertical conduction terminal for electrically connecting the TFT array substrate 10 and the counter substrate 20 and wiring such as a counter electrode potential line provided on the TFT array substrate 10. An electrode potential can be supplied.

  According to the liquid crystal device 1 according to the present embodiment, it is not necessary to create a complicated connection structure for electrically connecting the TFT array substrate 10 and the counter substrate 20 to each other, and each of the TFT array substrate 10 and the counter substrate 20 is provided. It is possible to simplify the configuration of the conductive portion such as the wiring to be built. According to such a liquid crystal device 1, it is possible to eliminate the connection resistance at the upper and lower conduction terminals that electrically connect the TFT array substrate 10 and the counter substrate 20, and it is possible to reduce conduction defects. In addition, according to the liquid crystal device 1 according to the present embodiment, since the FPC 500 is sandwiched between the TFT array substrate 10 and the counter substrate 20, the liquid crystal device 1 can be downsized.

  Note that the connection terminals provided on both sides of the FPC 500 may be electrically connected to each other by a conductive portion that penetrates the FPC 500.

  The scanning line driving circuit 104 is provided along two sides adjacent to the one side so as to be covered with the frame light shielding film 53. Further, in order to connect the two scanning line driving circuits 104 provided on both sides of the image display area 10 a in this way, a plurality of the pixel lines are covered along the remaining side of the TFT array substrate 10 and covered with the frame light shielding film 53. Wiring 105 is provided.

  1 and 2, on the TFT array substrate 10, in addition to the drive circuits such as the data line drive circuit 101 and the scanning line drive circuit 104, the image signal on the image signal line is sampled to obtain data. Sampling circuit that supplies lines, precharge circuit that supplies pre-charge signals of a predetermined voltage level to multiple data lines in advance of image signals, inspection of quality, defects, etc. of the electro-optical device during production or shipment An inspection circuit or the like may be formed.

<2: Modification>
Next, a modification of the electro-optical device according to the present embodiment will be described with reference to FIGS. 4 and 5. FIG. 4 is a plan view of the liquid crystal device 1A according to this example, and FIG. 5 is a cross-sectional view taken along the line VV ′ of FIG. In FIGS. 4 and 5, the same reference numerals are given to the portions common to the liquid crystal device 1 described above, and the detailed description is omitted. The liquid crystal device 1 </ b> A according to this example is characterized in that the fourth connection terminal is an extended portion formed by extending the counter electrode 21.

  4 and 5, the extending portion 21 a formed by extending the counter electrode 21 to the peripheral region is in contact with the second connection terminal 202 in a state where the FPC 500 is sandwiched between the TFT array substrate 10 and the counter substrate 20. 2 is electrically connected to the connection terminal 202. Therefore, since the counter electrode potential is directly supplied to the counter electrode 21 through the second connection terminal 202 during the operation of the liquid crystal device 1A, the wiring configuration in the counter substrate 20 can be simplified.

<4: Electronic equipment>
Next, the case where the liquid crystal device described above is applied to various electronic devices will be described with reference to FIG. The electronic apparatus according to the present embodiment is a projector that uses the liquid crystal device described above as a light valve. FIG. 6 is a plan view illustrating a configuration example of a projector that is an example of an electronic apparatus including the above-described liquid crystal device. As shown in FIG. 6, a lamp unit 1102 including a white light source such as a halogen lamp is provided inside the projector 1100. The projection light emitted from the lamp unit 1102 is separated into three primary colors of RGB by four mirrors 1106 and two dichroic mirrors 1108 arranged in the light guide 1104, and serves as a light valve corresponding to each primary color. The light enters the liquid crystal panels 1110R, 1110B, and 1110G.

  The configurations of the liquid crystal panels 1110R, 1110B, and 1110G are the same as those of the liquid crystal device described above, and are driven by R, G, and B primary color signals supplied from the image signal processing circuit. The light modulated by these liquid crystal panels enters the dichroic prism 1112 from three directions. In this dichroic prism 1112, R and B light is refracted at 90 degrees, while G light travels straight. Accordingly, as a result of the synthesis of the images of the respective colors, a color image is projected onto the screen or the like via the projection lens 1114.

  Here, paying attention to the display images by the liquid crystal panels 1110R, 1110B, and 1110G, the display image by the liquid crystal panel 1110G is horizontally reversed with respect to the display images by the liquid crystal panels 1110R and 1110B. Since light corresponding to the primary colors R, G, and B is incident on the liquid crystal panels 1110R, 1110B, and 1110G by the dichroic mirror 1108, it is not necessary to provide a color filter.

  In addition, according to the electronic apparatus according to the present embodiment, since the above-described small-sized liquid crystal device having a simple wiring configuration is provided, a projection-type display device, a mobile phone, an electronic notebook having a small size, Various electronic devices such as a word processor, a viewfinder type or a monitor direct-view type video tape recorder, a workstation, a videophone, a POS terminal, and a touch panel can be realized.

1 is a plan view showing a configuration of a liquid crystal device that is an embodiment of an electro-optical device according to the invention. FIG. It is the II-II 'sectional view taken on the line of FIG. It is the III-III 'sectional view taken on the line of FIG. FIG. 10 is a plan view showing a configuration of a modification of the liquid crystal device which is an embodiment of the electro-optical device according to the invention. FIG. 5 is a cross-sectional view taken along line VV ′ of FIG. 3. 1 is a plan view showing a configuration of a projector that is an embodiment of an electronic apparatus according to the invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,1A ... Liquid crystal device, 10 ... TFT array substrate, 20 ... Counter substrate, 21a ... Extension part, 201 ... 1st connection terminal, 202 ... 2nd connection terminal, 203 ... third connection terminal, 204 ... fourth connection terminal

Claims (7)

An element substrate having a pixel electrode formed on each of a plurality of pixels constituting a display region;
A counter substrate arranged to face the element substrate on the side where the pixel electrode is formed as viewed from the element substrate;
An external substrate sandwiched between the element substrate and the counter substrate in a region outside the display region;
A first connection terminal formed on a surface of the external substrate facing the element substrate;
A second connection terminal formed on a surface of the external substrate facing the counter substrate;
A third connection terminal provided on the element substrate in the outer region, and electrically connected to the first connection terminal;
An electro-optical device, comprising: a fourth connection terminal provided on the counter substrate in the outer region and electrically connected to the second connection terminal. The fourth connection terminal is electrically connected to a counter electrode formed on the counter substrate so as to face the pixel electrode,
The second connection terminal supplies a counter electrode potential to the counter electrode via the fourth connection terminal,
The third connection terminal is electrically connected to the pixel electrode;
The electro-optical device according to claim 1, wherein the first connection terminal supplies an image signal to the third connection terminal. The electro-optical device according to claim 2, wherein the fourth connection terminal is an extension portion in which the counter electrode extends to the outer region. In the outer region, the element substrate includes a first recess formed by partially digging a surface facing the external substrate,
The electro-optical device according to any one of claims 1 to 3, wherein the third connection terminal is formed in the first recess. A second recess formed by partially digging a surface of the counter substrate facing the external substrate in the outer region;
The electro-optical device according to any one of claims 1 to 3, wherein the fourth connection terminal is formed in the second recess. The outer region includes a fifth connection terminal formed on a surface of the external substrate facing the element substrate and electrically connected to the second connection terminal. The electro-optical device according to any one of 1 to 5. An electronic apparatus comprising the electro-optical device according to any one of claims 1 to 6.

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