JP2006018055A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent malfunctions, image quality and reliability degradations resulting from the temperature rise of the drive ICs even in a chip-on film (COF) structure provided 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 a liquid crystal display panel 10 sandwiching liquid crystals between a TFT substrate 11 and a facing substrate 12, a support 20 which is a frame to support the above liquid crystal display panel 10, a flexible film substrate 14 electrically connected with the above liquid crystal display panel 10, and an IC 15 to drive the above liquid crystal display panel 10. Then, the above drive IC 15 is disposed on the above film substrate 14 making its position extend farther than the outer edges of the above support 20. <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. In addition, it is conceivable that the driving IC itself generates heat with its operation (energization). Such a temperature rise in the driving IC may cause a drive malfunction, a deterioration in the image quality of the display image due to the malfunction or the temperature rise, and a decrease in reliability of the liquid crystal display device itself.

  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 malfunction, image quality degradation, reliability degradation, and the like due to a temperature rise of a driving IC.

  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 support member that is a frame for supporting the liquid crystal display panel, a flexible film substrate electrically connected to the liquid crystal display panel, and driving the liquid crystal display panel And the driving IC is disposed on the film substrate, and the location of the driving IC is located further outward than the outer edge of the support member. It is what.

  In the liquid crystal display device having the above configuration, the liquid crystal display panel supported by the support member is driven by a driving IC disposed on the film substrate separately from the liquid crystal display panel, and the liquid crystal display panel is liquid crystal by the drive. The irradiation light from the light source included in the projector device is selectively transmitted and light modulation is performed on the irradiation light. However, the drive IC is located further outward than the outer edge of the support member. That is, the driving IC is disposed so as to be exposed to the outside of the support member. Therefore, since the driving IC is not covered with the support member, the heat generated in the driving IC can be easily released to the outside of the support member, that is, to the outside of the liquid crystal display device. become. In addition, since it is possible to cool the driving IC, for example, by arranging the driving IC in the path of the cooling air, it is very easy to suppress the temperature rise of the driving IC.

  As described above, in the liquid crystal display device according to the present invention, the heat dissipation of the driving IC can be facilitated and the temperature rise in the driving IC can be suppressed, so that high definition, high aperture, and low cost can be achieved. Even in the case where a driving IC is provided separately from the liquid crystal display panel in order to meet such demands, malfunction of the function as a driving circuit due to temperature rise will not be caused. In addition, improper light modulation in the liquid crystal display panel due to the malfunction, that is, deterioration of the image quality of the display image is not caused, and further, the image quality of the display image is deteriorated due to heat transfer from the driving IC to the liquid crystal display panel. It can be suppressed. 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 apparatus, 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. 2-7 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. Examples of such a frame 20 include a metal member or a resin member formed into a frame shape. 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.

  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, a flexible film substrate 14 that is electrically connected to each electrode of the TFT substrate 11 and the counter substrate 12 in the liquid crystal display panel 10 is attached to the liquid crystal display panel 10. A driving IC 15 having a function as a driving circuit for driving the liquid crystal display panel 10 is provided on the film substrate 14. Note that the details of the film substrate 14 and the driving IC 15 may be realized by using a known technique, and thus 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 the film substrate 14. (Abbreviated as “COF”). According to this COF 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 film substrate 14, it is possible to easily downsize each of the substrates 11 to 13 constituting the liquid crystal display panel 10, and to secure a high degree of freedom in layout. Become.

  By the way, the liquid crystal display device described here has a great feature in the location of the driving IC 15. That is, as shown in FIG. 4, the location where the driving IC 15 is disposed is located further outward than the outer edge of the support member of the liquid crystal display panel 10 (see A in the figure).

  Here, the “support member” refers to a member for supporting the liquid crystal display panel 10. Specifically, the frame 20 corresponds to this, but the light shielding plate 30 is also included in the support member here. Further, for example, as shown in FIG. 5, when a mounting plate 40 is attached to the frame 20 in order to attach the frame 20 of the liquid crystal display device to the dichroic prism 7 of the liquid crystal projector device, the mounting plate 40. Is also included in the support member here (see B in the figure).

  Further, “further outward than the outer edge of the support member” means outside the edge forming the outer shape (planar outer shape) of the support member as viewed from the light incident direction on the liquid crystal display device, that is, FIG. As shown in FIG. 4, it means a side farther from the effective pixel portion 16 of the liquid crystal display panel 10 than the outer edge which is the outer edge. The outer edge of the support member is not necessarily a rectangular shape as shown in FIG. 6A, and may have a notch 21 as shown in FIG. 6B, for example. In this case, the inside of the notch 21 also corresponds to “further outside than the outer edge”.

  As described above, when the drive IC 15 is disposed further outward than the outer edge of the support member, the drive IC 15 is disposed so as to be exposed to the outside of the support member. Therefore, since the driving IC 15 is not covered with a support member such as the frame 20 or the light shielding plate 30, the heat generated in the driving IC 15 can be easily released.

  In addition, if the driving IC 15 is located outside the outer edge of the support member, the driving IC 15 can be cooled. In general, the liquid crystal projector device includes a blower fan, and for example, as shown in FIG. 7, the blower fan causes an air flow around the liquid crystal display device. For this reason, if the driving IC 15 is located outside the outer edge of the support member, the driving IC 15 is arranged on the air flow (cooling air passage). Cooling is possible.

  From the above, according to the liquid crystal display device described here, the heat dissipation of the driving IC 15 is facilitated and the cooling of the driving IC 15 is also possible, so that the temperature rise of the driving IC 15 can be suppressed. it can. Therefore, when used in a liquid crystal projector device, even if the liquid crystal display device is configured with a COF structure in order to meet the demands for higher definition, higher aperture, lower cost, etc., the driving IC 15 caused by the temperature rise Will not cause any malfunction. Further, inappropriate light modulation in the liquid crystal display panel 10 due to the malfunction, that is, deterioration of the image quality of the display image is not caused, and furthermore, the image quality of the display image due to heat transfer from the driving IC 15 to the liquid crystal display panel 10. Deterioration can also be suppressed. 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 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.

  The driving IC 15 is desirably disposed on the light emitting side surface of the film substrate 14. If it is disposed on the surface on the emission side, light does not directly enter the driving IC 15, and the light (diffraction to the driving IC 15 is compared with the case where it is disposed on the surface on the light incident side. This is because the possibility of incidence of light or the like is reduced. That is, since the incidence of light on the driving IC 15 can be suppressed, the incidence of the light prevents the temperature of the driving IC 15 from rising, and the occurrence of carriers due to the incident light prevents the TFT from malfunctioning. can do.

  Next, another example of the liquid crystal display device according to the present invention will be described. FIG. 8 is an explanatory diagram showing another configuration example of a main part of the liquid crystal display device according to the present invention.

  As illustrated, in the liquid crystal display device described here, the driving IC 15 is not simply disposed so as not to be covered by the support member, but the flexible film substrate 14 on which the driving IC 15 is disposed. Has a bending point, so that the location of the driving IC 15 on the film substrate 14 is offset in a direction parallel to the direction of incidence of light on the liquid crystal display panel 10. The offset amount at this time is preferably such that the driving IC 15 is positioned further outward than the outer edge of the support member of the liquid crystal display panel 10. However, the term “further outward than the outer edge of the support member” as used herein refers to the light incident side further than the end surface of the support member on the light incident side to the liquid crystal display device or the light emission to the liquid crystal display device The light emission side is more than the end face of the support member on the side. Specifically, the light emission side is more than the frame 20 that is the support member as shown in FIG. 8A, the light incidence side is more than the light shielding plate 30 that is the support member as shown in FIG. The light emission side of the mounting plate 40, which is a support member as in (c), corresponds to this.

  Thus, if the location where the driving IC 15 is disposed is offset, the location where the driving IC 15 is disposed is located on the air blowing path by the air blowing fan of the liquid crystal projector device. Therefore, the cooling air flowing through the air blowing path is surely applied to the driving IC 15, thereby ensuring the cooling of the driving IC 15.

  However, when the location where the driving IC 15 is disposed is offset, it is desirable to fix the vicinity of the location where the driving IC 15 is disposed to the support member. Specifically, the film substrate 14 in the vicinity of the location where the driving IC 15 is disposed is attached to the frame 20 as shown in FIG. 8A, the light shielding plate 30 as shown in FIG. 8B, or as shown in FIG. Fixed to the mounting plate 40. Since the film substrate 14 is generally flexible and has a thickness of about 100 to 200 μm, for example, when cooling air is applied to the driving IC 15 at a wind speed of about 5 to 7 m / s, the film substrate 14 vibrates due to the influence. However, if the vicinity of the driving IC 15 having the largest mass on the film substrate 14 is fixed, the vibration of the film substrate 14 due to the influence of the cooling air can be suppressed. This is because occurrence of disconnection and increase in noise can be avoided.

  It is conceivable that the film substrate 14 is fixed to the support member via the heat conductive resin 50. The heat conductive resin 50 may be a heat conductive sheet based on acrylic rubber or ethylene propylene rubber (for example, TM sheet EP manufactured by EFCO), or an insulating high heat conductive resin material (for example, CN- manufactured by MERECO). 733) and the like, and has both thermal conductivity and elasticity.

  If the film substrate 14 and the support member are fixed via the heat conductive resin 50, the heat generated by the driving IC 15 can be transmitted to the support member via the film substrate 14 and the heat conductive resin 50. It becomes like this. Therefore, since the supporting member such as the frame 20, the light shielding plate 30, or the mounting plate 40 can be used as the heat radiating member, the temperature rise of the driving IC 15 can be reliably suppressed. Furthermore, even if the linear expansion coefficients of the film substrate 14 and the support member are different from each other due to the presence of the heat conductive resin 50, the difference in the amount of thermal strain between them can be reduced. The film can be absorbed by elasticity, and peeling of the fixing portion between the film substrate 14 and the support member does not occur.

  Next, still another example of the liquid crystal display device according to the present invention will be described. FIG. 9 is an explanatory view showing still another main configuration example of the liquid crystal display device according to the present invention.

  As illustrated, in the liquid crystal display device described here, the driving IC 15 is not simply disposed so as not to be covered with the support member, but the driving IC 15 is provided with a heat sink 17. The heat sink 17 is a device (heat radiator) for radiating the heat generated in the driving IC 15 to the outside, and is made of a metal member having a large surface area with a large number of fins, for example. It is conceivable that the heat sink 17 is fixed to the chip surface of the driving IC 15 via a heat conductive resin similar to the heat conductive resin 50 described above. This is because if the thermally conductive resin is interposed, the difference in linear expansion coefficient between the driving IC 15 and the heat sink 17 can be absorbed.

  When such a heat sink 17 is provided, heat can be radiated from the driving IC 15 very efficiently, and further suppression of the temperature rise of the driving IC 15 can be ensured. In addition, the heat sink 17 may be attached and the position where the driving IC 15 is disposed may be offset as described above. In that case, further temperature rise suppression can be expected.

  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 forming material, size, shape, and the like of the support member and the heat conductive resin 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 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 an example 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 the modification of the principal part structure. It is explanatory drawing (the 5) which shows the structural example of the liquid crystal display device which concerns on this invention, and is a top view of another modification of the principal part structure. It is explanatory drawing (the 6) which shows the structural example of the liquid crystal display device which concerns on this invention, and is a figure which shows typically the flow outline of the air around the liquid crystal display device. It is explanatory drawing which shows the other structural example of the liquid crystal display device which concerns on this invention, and is sectional drawing of the principal part structure. It is explanatory drawing which shows the other structural example of the liquid crystal display device which concerns on this invention, and is sectional drawing 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 effective pixel portion, 17 Heat sink, 20 ... frame, 21 ... notch, 30 ... light shielding plate, 40 ... mounting plate, 50 ... heat conductive resin

Claims (5)

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 support member that is a frame for supporting the liquid crystal display panel;
A flexible film substrate electrically connected to the liquid crystal display panel;
A driving IC for driving the liquid crystal display panel;
The liquid crystal display device, wherein the driving IC is disposed on the film substrate, and the disposed portion is located further outward than the outer edge of the support member. The film substrate has a bending point that offsets the placement location of the driving IC,
2. The liquid crystal display device according to claim 1, wherein the drive IC is located on a ventilation path by a fan of the liquid crystal projector device due to the bending point of the film substrate.   The liquid crystal display device according to claim 2, wherein the film substrate is fixed to the support member in the vicinity of a place where the driving IC is disposed.   The liquid crystal display device according to claim 3, wherein the film substrate is fixed to the support member through a heat conductive resin. The liquid crystal display device according to claim 1, further comprising a heat sink attached to the driving IC.

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