JP2006018056A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent malfunctions, image quality and reliability degradations resulting from light entering the drive IC even in a chip-on glass (COG) structure using a drive IC aside from a liquid crystal display panel in a liquid crystal display used in a liquid crystal projector apparatus. <P>SOLUTION: The liquid crystal display is composed of the liquid crystal display panel 10 which sandwiches liquid crystals between a TFT substrate 11 and a facing substrate 12, and an IC 15 to drive the above liquid crystal display panel 10. The above drive IC 15 is disposed on either one of the substrates composing the above liquid crystal display panel 10, and shading means 20, 30 are provided to shade the light to the above drive IC 15. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device used in a liquid crystal projector device.

  In recent years, a so-called liquid crystal projector device has been used which realizes a large screen image display by selectively transmitting light emitted from a light source using a liquid crystal display device and projecting the transmitted light on a screen. However, a liquid crystal display device used in such a liquid crystal projector device generally has a built-in drive circuit thereof. In such a liquid crystal display device, a thin film transistor (hereinafter abbreviated as “TFT”) often uses a polysilicon film having a higher electron mobility instead of an amorphous silicon film. Is high.

  However, there is an increasing demand for liquid crystal display devices for use in liquid crystal projector devices, such as higher definition, higher aperture, and lower cost. For this reason, it has been proposed that a liquid crystal display device for use in a liquid crystal projector device is externally installed rather than having a built-in drive circuit, as in a liquid crystal display device other than a liquid crystal projector device (for example, Patent Document 1). That is, by providing a driving IC for driving the liquid crystal display panel separately from the liquid crystal display panel portion constituting the effective pixels, the liquid crystal display panel can increase the effective pixel area and can be obtained from the same substrate. It is possible to increase the number of display panel portions, etc., thereby meeting the demands for higher definition, higher aperture, lower costs, and the like.

JP 2003-332585 A

  However, when the liquid crystal display device is used in a liquid crystal projector device, strong light of about 40 million lux, for example, in terms of white light is incident on the liquid crystal display panel portion of the liquid crystal display device. Such strong light incidence may cause a rise in temperature around the liquid crystal display panel portion, particularly a rise in temperature of the driving IC. It is also conceivable that when strong light is directly incident on the driving IC, carriers are generated in the driving IC by the incident light. That is, the light incident on the driving IC provided separately may cause a temperature rise of the driving IC, generation of carriers, and the like, which may cause the liquid crystal display panel portion to malfunction. Such a malfunction of driving in the driving IC leads to deterioration in the image quality of the display image in the liquid crystal projector device, reduction in reliability of the liquid crystal display device itself, and the like.

  Therefore, in order to meet the demands for high definition, high aperture, low cost, etc., the present invention provides a driving IC that functions as a driving circuit separately from the liquid crystal display panel portion. It is an object of the present invention to provide a liquid crystal display device capable of preventing image quality deterioration, reliability reduction, and the like due to the malfunction without causing the drive IC to malfunction.

  The present invention is a liquid crystal display device devised to achieve the above object. That is, a liquid crystal display device that is used in a liquid crystal projector device that displays an enlarged projection image and performs light modulation with respect to irradiation light from a light source included in the liquid crystal projector device, between a TFT substrate and a counter substrate. A liquid crystal display panel sandwiching liquid crystal, a driving IC for driving the liquid crystal display panel disposed on any substrate constituting the liquid crystal display panel, and shielding the driving IC And a light shielding means for performing.

In the liquid crystal display device having the above configuration, the liquid crystal display panel is driven by a driving IC disposed on the substrate separately from the liquid crystal display panel, and the liquid crystal display panel is driven by a light source from the liquid crystal projector device. The irradiation light is selectively transmitted and light modulation is performed on the irradiation light. However, the driving IC is provided with a light shielding means, and the light shielding means shields the irradiation light from the light source of the liquid crystal projector apparatus. That is, irradiation light from the light source does not directly enter the driving IC. Therefore, no temperature rise or carrier generation occurs in the driving IC.

  As described above, in the liquid crystal display device according to the present invention, the irradiation light is not directly incident on the driving IC. Therefore, in order to meet demands for high definition, high aperture, low cost, etc. Even when a driving IC is provided separately from the display panel, a malfunction of a function as a driving circuit due to light incident on the driving IC is not caused. Further, inappropriate light modulation in the liquid crystal display panel due to the malfunction, that is, deterioration of the image quality of the displayed image is not caused. For these reasons, in the liquid crystal display device according to the present invention, it is possible to improve the reliability of the driving IC that functions as the driving circuit of the liquid crystal display panel, and to improve the reliability of the liquid crystal display device itself. it can. In addition, since it is not necessary to increase the number of special components, the reliability can be improved without causing an increase in apparatus cost.

  Hereinafter, a liquid crystal display device according to the present invention will be described with reference to the drawings.

  First, prior to the description of the liquid crystal display device according to the present invention, a liquid crystal projector device using the liquid crystal display device will be described. As the liquid crystal projector device, a so-called three-plate type device in which the liquid crystal display device is provided corresponding to each of R (red) color, G (green) color, and B (blue) color is widely known. FIG. 1 is a schematic diagram illustrating a schematic configuration example of a three-plate liquid crystal projector apparatus.

  As shown in FIG. 1, in the liquid crystal projector device, the light emitted from the light source 1 includes a filter 2a that cuts infrared rays and ultraviolet rays, a fly-eye lens 2b, and a PS separator / synthesizer 2c that converts a non-polarized wave into a polarized wave. After that, it is separated into RGB color component light by a dichroic mirror 3 that reflects only light in a specific wavelength band, and corresponds to each RGB color using a total reflection mirror 4 and a condenser lens 5 as necessary. The liquid crystal display devices 6R, 6G, and 6B are provided. Then, after each liquid crystal display device 6R, 6G, and 6B performs light modulation according to the video signal, each light component that has been light-modulated is synthesized by the dichroic prism 7 and enlarged and projected by the projection lens 8. The In this way, the liquid crystal projector device displays a color image on the screen.

  Next, the liquid crystal display devices 6R, 6G, and 6B used in the liquid crystal projector device having the above configuration, that is, the liquid crystal display device according to the present invention will be described. 2-5 is explanatory drawing which shows the structural example of the liquid crystal display device based on this invention.

  As shown in FIGS. 2 and 3, the liquid crystal display device described here includes a liquid crystal display panel 10, a frame 20, and a light shielding plate 30. Among these, the frame 20 is disposed on the light emission side of the liquid crystal display panel 10 and serves as a frame for supporting the liquid crystal display panel 10. As such a frame 20, for example, a metal member such as aluminum (Al), magnesium (Mg), and stainless steel (SUS) excellent in thermal conductivity, or a resin member also excellent in thermal conductivity is formed into a frame shape. The thing which was done is mentioned. Further, the light shielding plate 30 is disposed on the light incident side of the liquid crystal display panel 10, and is for shielding light from entering other than the effective pixel portion of the liquid crystal display panel 10. Examples of such a light shielding plate 30 include a plate in which an opening having a shape corresponding to an effective pixel portion is formed on, for example, a metal plate or a resin plate excellent in thermal conductivity.

  The liquid crystal display panel 10 has a liquid crystal (not shown) sandwiched between a TFT substrate 11 and a counter substrate 12. On the TFT substrate 11, TFTs that are pixel electrodes constituting pixels are arranged in a matrix. On the other hand, a counter electrode or a common (common) electrode is disposed on the counter substrate 12 facing this with the liquid crystal interposed therebetween. With such a configuration, in the liquid crystal display panel 10, when a voltage is applied between the opposed electrodes, the director alignment direction of the liquid crystal molecules becomes one direction, and the uniaxial birefringence anisotropy is expressed. The amount of transmitted light can be controlled, and the light modulation according to the video signal can be performed on the irradiation light from the light source 1. A cover glass 13 for protecting the TFT substrate 11 and the counter substrate 12 is provided on each of the light incident side and the light emitting side of the liquid crystal display panel 10.

  However, in the liquid crystal display panel 10, a voltage is applied to each electrode in the TFT substrate 11 and the counter substrate 12 to drive the liquid crystal display panel 10 in order to meet demands for higher definition, higher aperture, lower cost, and the like. For this purpose, a driving circuit is not built in the liquid crystal display panel but is externally attached. That is, the liquid crystal display panel 10 functions as a drive circuit for driving the liquid crystal display panel 10 in addition to the flexible film substrate 14 for receiving a signal supply from a host device (for example, a control unit of the liquid crystal projector device). Is provided on the TFT substrate 11 constituting the liquid crystal display panel 10. The driving IC 15 is electrically connected to the respective electrodes on the TFT substrate 11 and the counter substrate 12, thereby driving the liquid crystal display panel 10. The driving IC 15 may be disposed on the counter substrate 12 instead of on the TFT substrate 11. In other words, it may be disposed on any substrate constituting the liquid crystal display panel 10. The details of the film substrate 14 and the driving IC 15 may be realized by using a known technique, and the description thereof is omitted here.

  As described above, the liquid crystal display device is provided with the driving IC 15 separately from the liquid crystal display panel 10, and the driving IC 15 is provided on any substrate constituting the liquid crystal display panel 10. It has a chip-on-glass (hereinafter abbreviated as “COG”) structure. According to this COG structure, since the driving IC 15 is separate from the liquid crystal display panel 10, the effective pixel area in the liquid crystal display panel 10 is increased, the number of liquid crystal display panel 10 parts that can be obtained from the same substrate is increased, and the like. This makes it possible to realize high definition, high aperture, low cost, etc. of the liquid crystal display device. In addition, since the driving IC 15 is disposed on the TFT substrate 11, for example, in the vicinity of each electrode, the responsiveness when driving the liquid crystal display panel 10 is excellent, and the driving IC 15 is vibrated. The effects of the above can be reduced, and stable driving operation can be realized by these points.

  Incidentally, the liquid crystal display device described here has a great feature in the positional relationship between the driving IC 15 and the frame 20 or the light shielding plate 30. That is, as shown in FIG. 3A or 3B, at least one of the frame 20 and the light shielding plate 30 is on the light incident side with respect to the driving IC 15 disposed on the TFT substrate 11. Those located, preferably both the frame 20 and the light shielding plate 30 are arranged so as to cover the driving IC 15. That is, at least one of the frame 20 and the light shielding plate 30, preferably both edges, extend to the outside (the side far from the effective pixel portion of the liquid crystal display panel 10) from the location where the driving IC 15 is disposed.

  Thus, when the edge of the frame 20 or the light shielding plate 30 extends outside the driving IC 15, the light emitted from the light source 1 of the liquid crystal projector device is blocked by the frame 20 or the light shielding plate 30. , It does not directly enter the driving IC 15. That is, the frame 20 or the light shielding plate 30 functions as a light shielding means for performing light shielding on the driving IC 15.

  From the above, according to the liquid crystal display device described here, the frame 20 or the light shielding plate 30 functions as a light shielding means, and the irradiation light from the light source 1 is not directly incident on the driving IC 15. There is no temperature rise or carrier generation caused by light incidence in the IC 15 for use. Therefore, when used in a liquid crystal projector device, even if the liquid crystal display device is configured with a COG structure in order to meet the demands for high definition, high aperture, low cost, etc., light is incident on the driving IC 15. Therefore, the malfunction of the function as a drive circuit due to the above is not caused. Inappropriate light modulation in the liquid crystal display panel 10 due to the malfunction, that is, image quality deterioration of the display image is not caused. For these reasons, in the liquid crystal display device described here, it is possible to improve the reliability of the driving IC 15 that functions as the driving circuit of the liquid crystal display panel 10 and to improve the reliability of the liquid crystal display device itself. Can do.

  In particular, when both the frame 20 and the light shielding plate 30 function as light shielding means, not only the light directly emitted from the light source 1 but also the diffracted light and reflected light accompanying the light irradiation are used. It is possible to prevent the light from entering the driving IC 15 by blocking it. Therefore, if both the frame 20 and the light shielding plate 30 function as light shielding means so as to dispose light shielding means on both sides of the incident light incident side and the irradiation light emission side from the light source 1, the driving IC 15 It is possible to more reliably prevent the occurrence of malfunction due to light incident on the.

  Further, if the frame 20 or the light shielding plate 30 is used as the light shielding means, it is not necessary to add new components or the like, so that it is possible to improve the reliability without increasing the apparatus cost.

However, as the light shielding means, in addition to the frame 20 or the light shielding plate 30, for example, as shown in FIG. The resin member 16 only needs to have light-shielding properties, insulating properties, and elasticity, and specific examples thereof include dealcohol-free RTV (Room Temperature Volcanizable) silicone rubber. Further, if the resin member 16 is provided corresponding to the location where the driving IC 15 is disposed, the resin member 16 may be provided so as to cover the driving IC 15 as shown in FIG. Thus, even if the driving IC 15 is provided on the opposite side of the TFT substrate 11, or an insulating film (SiO ₂ , SiN, etc.) 17 formed on the surface of the driving IC 15 as shown in FIG. It may be provided so as to cover the driving IC 15 via the. Further, if the irradiation light is blocked from both the incident side and the emission side of the irradiation light, the resin member 16 is attached to either the frame 20 or the light shielding plate 30 as shown in FIGS. What is necessary is just to combine or arrange | position the resin member 16 on both surfaces of the TFT substrate 10. If such a resin member 16 is used as a light shielding means, the driving IC 15 can be easily shielded from light without complicating the shape of the frame 20 or the light shielding plate 30.

  Next, another example of the liquid crystal display device according to the present invention will be described. 6 to 9 are explanatory views showing other configuration examples of the liquid crystal display device according to the present invention.

  In the liquid crystal display device described here, the light shielding means not only simply shields light from the driving IC 15 but also functions as a heat radiating means that receives heat from the driving IC 15 through a contact portion with the surface of the driving IC 15. Have both. That is, as shown in FIG. 6, the driving IC 15 has a contact portion with either the frame 20 (see FIG. 6 (a)) or the light shielding plate 30 (see FIG. 6 (b)) functioning as a light shielding means. is doing.

  With such a contact portion, the heat generated by the driving IC 15 can be transmitted to either the frame 20 or the light shielding plate 30. Therefore, the heat generated in the driving IC 15 can be radiated using the frame 20 or the light shielding plate 30 as a heat radiating means. Therefore, it becomes possible to suppress the temperature rise of the driving IC 15, and in addition to blocking the light emitted from the light source 1, it is possible to ensure the prevention of malfunction in the driving IC 15.

  At this time, a thermal conductive resin 50 is interposed between the driving IC 15 and the frame 20 or the light shielding plate 30, and the driving IC 15 is connected to the frame 20 or the light shielding plate 30 via the thermal conductive resin 50. It is desirable that the heat transfer be performed. If heat transfer is performed via the heat conductive resin 50, even if the linear expansion coefficients between the driving IC 15 and the frame 20 or the light shielding plate 30 are different from each other, the difference in the amount of thermal strain between them can be reduced. Since it can be absorbed by the elasticity of the heat conductive resin 50, the heat generated in the driving IC 15 can be reliably transferred to the frame 20 or the light shielding plate 30 without causing separation of the contact portion. Because it becomes. Examples of such a heat conductive resin 50 include a heat conductive sheet (for example, TM sheet EP manufactured by Fuko Co.) based on acrylic rubber or ethylene propylene rubber, and an insulating high heat conductive resin material (for example, MERECO). And those formed using CN-733).

  Further, as shown in FIGS. 7 to 8, the frame 20 or the light shielding plate 30 that is the contact partner of the driving IC 15 has a processed portion for increasing the contact area with the surface of the driving IC 15. It is desirable to have. Examples of the parts to be processed include a groove processing part 21 as shown in FIG. 7A, a protrusion processing part 22 as shown in FIG. 7B, and a bending part 31 as shown in FIGS. However, as long as it is for increasing the contact area, it may be other (for example, uneven processing). If such a part to be processed is provided, the contact area increases accordingly, and the efficiency of heat transfer from the driving IC 15 can be improved. Therefore, it is very effective in suppressing the temperature rise of the driving IC 15.

  In the above-described embodiments, the present invention has been described with reference to preferred specific examples. However, the present invention can be modified as appropriate without departing from the scope of the present invention. In particular, the material, size, shape, and the like of the light shielding means are not limited to the above-described embodiments.

It is a schematic diagram showing a schematic configuration example of a three-plate liquid crystal projector device. It is explanatory drawing (the 1) which shows the structural example of the liquid crystal display device which concerns on this invention, and is a disassembled perspective view of the schematic structure. It is explanatory drawing (the 2) which shows the structural example of the liquid crystal display device which concerns on this invention, and is a sectional side view of an example of the schematic structure. It is explanatory drawing (the 3) which shows the structural example of the liquid crystal display device which concerns on this invention, and is a sectional side view of the modification of the principal part structure. It is explanatory drawing (the 4) which shows the structural example of the liquid crystal display device which concerns on this invention, and is a sectional side view of another modification of the principal part structure. It is explanatory drawing (the 1) which shows the other structural example of the liquid crystal display device which concerns on this invention, and is a sectional side view of an example of the schematic structure. It is explanatory drawing (the 2) which shows the other structural example of the liquid crystal display device which concerns on this invention, and is a sectional side view of the modification of the principal part structure. It is explanatory drawing (the 3) which shows the other structural example of the liquid crystal display device which concerns on this invention, and is a sectional side view of another modification of the principal part structure.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Light source, 2a ... Filter, 2b ... Fly eye lens, 2c ... PS isolation | separation synthesizer, 3 ... Dichroic mirror, 4 ... Total reflection mirror, 5 ... Condenser lens, 6R, 6G, 6B ... Liquid crystal display device, 7 Dichroic prism, 8 projection lens, 10 liquid crystal display panel, 11 TFT substrate, 12 counter substrate, 13 cover glass, 14 film substrate, 15 driving IC, 16 resin member, 17 insulation Membrane, 20 ... Frame, 21 ... Groove processing part, 22 ... Protrusion processing part, 30 ... Light shielding plate, 31 ... Bending part, 50 ... Heat conductive resin

Claims (9)

A liquid crystal display device that is used in a liquid crystal projector device that displays an enlarged projection image, and that performs light modulation on irradiation light from a light source included in the liquid crystal projector device,
A liquid crystal display panel having a liquid crystal sandwiched between a TFT substrate and a counter substrate;
A driving IC for driving the liquid crystal display panel, disposed on any substrate constituting the liquid crystal display panel;
A liquid crystal display device comprising: a light shielding means for shielding light from the driving IC.   2. The liquid crystal display device according to claim 1, wherein the light shielding means is disposed on both sides of an incident side of the irradiation light from the light source and an emission side of the irradiation light.   The liquid crystal display device according to claim 1, wherein the light shielding unit includes a support member that supports the liquid crystal display panel.   The liquid crystal display device according to claim 1, wherein the light shielding means includes a light shielding plate having an opening provided in accordance with an effective pixel portion of the liquid crystal display panel.   The liquid crystal display device according to claim 1, wherein the light shielding unit is made of a resin member provided corresponding to a place where the driving IC is disposed.   The light shielding means is provided corresponding to a support member for supporting the liquid crystal display panel, a light shielding plate having an opening provided in accordance with an effective pixel portion of the liquid crystal display panel, or a place where the driving IC is disposed. 3. The liquid crystal display device according to claim 2, wherein any one of the resin members or a combination of the two is used.   2. The liquid crystal display device according to claim 1, wherein the light shielding means also has a function as a heat radiating means for receiving heat from the driving IC through a contact portion with the surface of the driving IC.   A heat conductive resin interposed between the light shielding means and the surface of the driving IC, and heat transfer from the driving IC to the light shielding means is performed via the heat conductive resin. The liquid crystal display device according to claim 7. 9. The liquid crystal display device according to claim 8, wherein the light shielding means includes a portion to be processed for increasing a contact area with the surface of the driving IC.

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