JP2009036917A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device wherein influence of heat of a backlight is not received and deflection of a liquid crystal panel can be suppressed. <P>SOLUTION: In the liquid crystal display provided with the liquid crystal panel 1 having a display surface in front thereof and the backlight 4 illuminating the rear face of the liquid crystal panel 1, a deflection suppressing and heat shielding plate 2 having light transmissible properties is disposed on the rear face of the liquid crystal panel 1 and a deflection suppressing plate 3 having light transmissible properties is disposed on the front face of the liquid crystal panel 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device including a liquid crystal panel having a display surface on the front surface and a backlight for illuminating the back surface of the liquid crystal panel.

  A liquid crystal display device is small, thin, and has low power consumption. However, unlike a self-luminous device, it requires a backlight such as a fluorescent tube. That is, when the illumination light of the backlight from the back side of the panel is transmitted through the panel by applying a voltage to the liquid crystal panel in which the liquid crystal material is sealed between two glass plates to change the electro-optical characteristics of the liquid crystal material. An image is displayed on the front by controlling the transmittance of the light (see, for example, Patent Document 1).

On the other hand, in the plasma display device, a high thermal conductivity member is sandwiched between the back surface of the plasma display panel and a circuit board on which electronic components, electronic circuits, etc. for driving the plasma display panel are mounted. An invention is disclosed in which the circuit board is thermally integrated with the circuit board, and the heat generated on the back surface of the plasma display panel is radiated from the circuit board together with the heat generated from the circuit board by a heat radiating fan or the like (patent) Reference 2).
JP 2007-86650 A JP-A-11-284379

  Since the backlight generates heat (for example, around 60-70 ° C.), the liquid crystal panel is warmed by this heat, and the entire panel becomes hot. As a result, the temperature rise of the panel is increased, and the display characteristics of the liquid crystal material sealed inside the panel may change, and the image quality may deteriorate. The portion of the liquid crystal display device that becomes high in temperature is a portion of the backlight, and it is necessary to prevent the heat of the backlight from being conducted to the liquid crystal panel. Therefore, in the liquid crystal display device, unlike the plasma display device described above, it is necessary to thermally shield between the back surface of the display panel and the backlight. In particular, an increase in the size of a liquid crystal television increases the display area, and the amount of light from the backlight needs to be increased. For this reason, the number of necessary light sources such as fluorescent tubes also increases, and the power consumption increases greatly in proportion to the display area, so that the heat from the backlight also increases. Conventionally, various means for dispersing heat, such as heat radiation to the substrate side of the backlight, heat radiation by a fan, and heat radiation by natural convection in a cabinet, have been performed, but it is not sufficient. As a result, the importance of preventing the temperature rise of the liquid crystal panel due to the heat of the backlight is increasing.

  Further, since the liquid crystal panel is placed sideways when assembling a large-sized liquid crystal television, the center part of the panel is bent downward due to its own weight, and the panel may be distorted. In the worst case, the glass may be broken. Even when not being assembled, when used as a station time display board, the panel center part may be bent forward in a forward tilted state where the panel is tilted to the front side. There is also a possibility of bending due to vibration or mechanical shock.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a liquid crystal display device that suppresses bending of a liquid crystal panel and is hardly affected by heat from a backlight. It is another object of the present invention to provide a liquid crystal display device capable of suppressing the deflection of the liquid crystal panel and protecting the panel display surface.

The liquid crystal display device according to the present invention is a liquid crystal display device comprising a liquid crystal panel having a display surface on the front surface and a backlight for illuminating the back surface of the liquid crystal panel, and the back surface of the liquid crystal panel has translucency. A bending suppression and heat shielding plate is arranged.
According to the present invention, the light from the backlight is transmitted through the translucent deflection suppressing and heat shielding plate to illuminate the back surface of the liquid crystal panel, and the heat generated by the backlight is transmitted to the liquid crystal panel by heat conduction or radiation. Is shielded by the deflection suppressing and heat shielding plate, and the temperature rise of the liquid crystal panel is suppressed.
Also, when the LCD panel is installed in a tilted state after being tilted to the back side, or when it is placed sideways when assembling the liquid crystal display device, or when it receives vibration or mechanical shock during transportation to the installation location, etc. Even if the center portion is bent downward, the panel is received by the bending suppression and heat shielding plate arranged on the back surface of the liquid crystal panel, and the bending is suppressed.

The liquid crystal display device according to the present invention is characterized in that the deflection suppressing and heat shielding plate in the above-described invention is attached to the back surface of the liquid crystal panel.
According to the present invention, when the liquid crystal panel is in the rearward tilted state or the horizontal state, the center portion of the panel is prevented from being bent downward, and the liquid crystal panel is tilted to the front side. Even when the panel center portion is bent forward when it is installed in an inclined state, the panel is prevented from being bent by being pulled by the deflection suppressing and heat shielding plate attached to the back surface of the liquid crystal panel. In addition, the center of the panel is also prevented from being bent when subjected to vibration or mechanical shock during transportation to the installation site.

The liquid crystal display device according to the present invention is characterized in that the deflection suppressing and heat shielding plate in the above-described invention is made of a glass material.
According to the present invention, since the glass material has a low thermal conductivity and a low coefficient of thermal expansion, it is suitable as a material for shielding the backlight from being transmitted to the liquid crystal panel, and at the same time, the glass material has a large rigidity, Since the bending suppression effect is also high, a bending suppression and heat shielding plate capable of satisfactorily realizing the heat shielding effect and the bending suppression effect by the glass material is obtained.

The liquid crystal display device according to the present invention is characterized in that a transflection suppressing plate is disposed in front of the liquid crystal panel in the above-described invention.
According to the present invention, when the liquid crystal panel is installed in a forward inclined state inclined to the front side or when subjected to vibration or mechanical shock during transportation to the installation location, the center of the panel may be bent forward. The panel is received by the deflection suppressing plate arranged in front of the liquid crystal panel, and the deflection is suppressed. Further, it is possible to prevent the external force from hitting the display surface of the panel and damaging it by the deflection suppressing plate arranged in front of the liquid crystal panel.

The liquid crystal display device according to the present invention is characterized in that the thickness of the deflection suppressing plate in the above-described invention is formed thinner than the thickness of the deflection suppressing and heat shielding plate.
The deflection suppressing and heat shielding plate on the back side of the liquid crystal panel is provided for shielding heat from the backlight, while the deflection suppressing plate on the front side needs to release the heat of the liquid crystal panel. According to the present invention, by forming the deflection suppressing plate on the front side of the liquid crystal panel thinner than the thickness of the deflection suppressing and heat shielding plate on the back side, the effect of shielding the heat from the backlight on the panel rear side can be obtained. While ensuring, the effect of heat release from the front side of the panel can be enhanced.

The liquid crystal display device according to the present invention is characterized in that the thermal conductivity of the deflection suppressing plate in the above-described invention is higher than the thermal conductivity of the deflection suppressing and heat shielding plate.
As described above, the front-side deflection suppressing plate needs to release the heat of the liquid crystal panel. However, according to the present invention, the thermal conductivity of the front-side deflection suppressing plate is set to be the back-side deflection suppressing function. By making it higher than the thermal conductivity of the heat shielding plate, it is possible to enhance the heat release effect from the front side of the panel while ensuring the heat shielding effect from the backlight on the back side of the panel.

  According to the liquid crystal display device according to the present invention, since the temperature rise of the liquid crystal panel due to the heat of the backlight is suppressed by the deflection suppressing and heat shielding plate arranged on the back side of the liquid crystal panel, for example, a large size arranged vertically. In the liquid crystal panel of the liquid crystal television, the temperature difference between the upper part and the lower part is reduced, and the upper display surface becomes whitish and problems such as afterimages can be avoided and a uniform display operation can be realized on the entire display surface. At the same time, when the liquid crystal panel is installed in a backward tilted state, sideways state, forward tilted state, etc., the liquid crystal panel is restrained from being bent. An apparatus is provided.

  Further, a liquid crystal display device capable of suppressing the deflection of the liquid crystal panel and protecting the panel display surface against an external force by using the back side deflection suppressing and heat shielding plate and the front side deflection suppressing plate of the liquid crystal panel is provided. Is done.

  Embodiments of a liquid crystal display device according to the present invention will be described below with reference to the drawings.

Embodiment 1
FIG. 1 is a cross-sectional view showing a configuration of a liquid crystal display device according to Embodiment 1 of the present invention. The liquid crystal display device according to the present embodiment includes a liquid crystal panel 1 having a display surface on the front surface and a backlight 4 that illuminates the back surface of the liquid crystal panel 1. A suppression / heat shielding plate 2 is disposed. Here, the deflection suppressing / heat shielding plate 2 is used to shield the heat generated by the backlight 4 from being transmitted to the liquid crystal panel 1 and to suppress the deflection of the liquid crystal panel 1. Further, a light-transmitting deflection suppressing plate 3 is disposed on the front surface of the liquid crystal panel 1.

  The bending suppression and heat shielding plate 2, the liquid crystal panel 1, and the bending suppression plate 3 are rectangular from the front side in a state where they are sequentially stacked and received on the flange-shaped protrusion 10A provided on the inner periphery of the rectangular box-shaped holding frame 10. The presser frame 11 is sandwiched and assembled. The holding frame 10 and the presser frame 11 are coupled by screws 14. The holding frame 10 and the presser frame 11 are made of metal and have dimensions that match the liquid crystal panel 1, and an image of the liquid crystal panel 1 can be seen from the front side through the opening 11 a of the presser frame 11. The back portion of the holding frame 10 is attached to a support column 12 erected on the fixed base 13.

  The backlight 4 is composed of a plurality of linear cold cathode tubes juxtaposed in the vertical direction in a horizontally placed state, and is attached to a backlight receiving plate 10 </ b> B provided inside the holding frame 10. A drive circuit board 5 is attached to the back side of the backlight receiving plate 10B.

  The deflection suppressing / heat shielding plate 2 and the deflection suppressing plate 3 are made of tempered glass. Tempered glass has a low thermal conductivity (specifically, about 1.0 W / m · K) and a small thermal expansion, so that the heat of the backlight source 4 is prevented from being transmitted to the liquid crystal panel 1 and is suppressed and heated. It is suitable as a material for the shielding plate 2. An optical sheet 6 made of a diffusion plate is disposed on the back side of the deflection suppressing / heat shielding plate 2. The thicknesses of the deflection suppressing / heat shielding plate 2 and the deflection suppressing plate 3 are preferably sufficient to ensure rigidity for preventing the liquid crystal panel 1 from being bent. As an example of the plate thickness, the thickness of the deflection suppressing / heat shielding plate 2 and the deflection suppressing plate 3 is about 3 mm with respect to the thickness of 1.8 mm of the liquid crystal panel 1. Further, the thickness of the deflection suppressing plate 3 may be made thinner than the thickness of the deflection suppressing / heat shielding plate 2 to enhance the effect of heat release from the front side of the liquid crystal panel 1.

  Here, when the liquid crystal panel 1 is installed in a forward tilted state by the front-side deflection suppressing plate 3, it is possible to effectively prevent the center portion of the panel from being depressed forward, and for example, a remote for a home game machine or a television set. Controllers, vacuum cleaner hoses, suction ports, and the like hit the liquid crystal panel 1 to effectively prevent damage such as breakage of the panel glass and scratches on the display surface.

  Although not shown, even when a large-sized liquid crystal display device such as a 65 type is assembled with the display surface of the panel facing sideways, the deflection suppressing and heat shielding plate 2 installed on the back surface of the liquid crystal panel 1. Thus, the center part of the panel is depressed by its own weight, and it is possible to effectively prevent the panel from being greatly distorted, and even when the liquid crystal panel is inclined to the back side and installed in a tilted state, It can prevent that the center part of a panel sinks back and bends.

  Although not shown, the liquid crystal panel 1 has a configuration in which peripheral portions of a pair of transparent substrates arranged opposite to each other are sealed with a sealing material or the like, and a liquid crystal substance is filled in a gap between the substrates. One transparent substrate is formed with transparent pixel electrodes arranged in a matrix and TFTs for controlling the supply of electric charges to the pixel electrodes, and the other transparent substrate is called a transparent common electrode. Common electrode is formed. The gate and source of the TFT are connected to the output stages of the gate driver and source driver, respectively.

  In addition, two polarizing plates whose polarization axes are orthogonal to each other are attached to the surface of the transparent substrate, and the on / off of each pixel electrode is controlled by the gate signal input from the gate driver. By applying the input data signal to each pixel electrode during the ON period, the light transmittance of the liquid crystal substance is controlled based on the voltage difference between the voltage applied to the pixel electrode and the voltage applied to the counter electrode. ing.

Embodiment 2
FIG. 2 is a cross-sectional view showing the configuration of the second embodiment of the liquid crystal display device according to the present invention. The difference from the first embodiment is that the back side deflection suppressing and heat shielding plate 2 of the liquid crystal panel 1 is attached to the back side of the liquid crystal panel 1 and the deflection suppressing plate 3 is arranged in front of the liquid crystal panel 1. The other configuration is the same as that of the first embodiment.

  For example, an adhesive made of a transparent resin material or the like is formed as a thin adhesive layer 7 between the deflection suppressing / heat shielding plate 2 and the liquid crystal panel 1. This can be realized by curing the adhesive layer 7.

  According to the second embodiment, even when there is no deflection suppressing plate 3 on the front side of the liquid crystal panel 1, when the panel is installed in a forward tilted state by the deflection suppressing and heat shielding plate 2 on the back side of the liquid crystal panel 1, It is possible to effectively suppress the central portion of the head from being bent forward.

Next, another embodiment will be described.
In the first embodiment described above, the deflection suppressing / heat shielding plate 2 and the deflection suppressing plate 3 are made of the same glass material. However, the thermal conductivity of the deflection suppressing plate 3 is controlled by the deflection suppressing / heat shielding. It may be higher than the thermal conductivity of the plate 2. For example, the thermal conductivity of tempered glass is about 1.0 W / m · K, the thermal conductivity of quartz is about 8 W / m · K, and the thermal conductivity of polycarbonate resin is about 0.25 W / m · K. Therefore, the bending suppression plate 3 may be made of quartz, and the bending suppression and heat shielding plate 2 may be made of tempered glass or polycarbonate resin, or the bending suppression plate 3 may be made of tempered glass to suppress bending. The dual heat shield plate 2 may be made of polycarbonate resin.

  In addition, the polarizing plate attached to the back surface of the liquid crystal panel 1 may be attached to the back surface of the deflection suppressing and heat shielding plate 2, and when the bending suppressing plate 3 is provided, the other polarizing plate is suppressed. You may make it stick on the front of the board 3. FIG.

It is sectional drawing which shows the structure of Embodiment 1 of the liquid crystal display device which concerns on this invention. It is sectional drawing which shows the structure of Embodiment 2 of the liquid crystal display device which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal panel 2 Deflection suppression and heat shielding board 3 Deflection suppression board 4 Backlight 5 Drive circuit board 6 Optical sheet 7 Adhesion layer 10 Holding frame 10A Protrusion part 10B Backlight receiving plate 11 Presser frame 11a Opening part 12 Support | pillar 13 Fixing base 14 Screw

Claims (6)

In a liquid crystal display device comprising a liquid crystal panel having a display surface on the front and a backlight for illuminating the back surface of the liquid crystal panel,
A liquid crystal display device, wherein a translucent deflection suppressing and heat shielding plate is disposed on a back surface of the liquid crystal panel.   The liquid crystal display device according to claim 1, wherein the deflection suppressing and heat shielding plate is attached to a back surface of the liquid crystal panel.   The liquid crystal display device according to claim 1, wherein the deflection suppressing and heat shielding plate is made of a glass material.   4. The liquid crystal display device according to claim 1, wherein a transflection suppressing plate is disposed in front of the liquid crystal panel. 5.   5. The liquid crystal display device according to claim 4, wherein a thickness of the deflection suppressing plate is thinner than a thickness of the deflection suppressing and heat shielding plate.   6. The liquid crystal display device according to claim 4, wherein a thermal conductivity of the deflection suppressing plate is higher than a thermal conductivity of the deflection suppressing and heat shielding plate.

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