JP2010243983A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-weight and highly-rigid liquid crystal display. <P>SOLUTION: The liquid crystal display 100 includes: a box-shaped casing 110 which is made of a synthetic resin and includes an opening on the front surface side; a light source 120 housed in the casing 110; a diffusion plate 130 which is made of the synthetic resin, fixed to at least two sides of the outer edge of the opening and increases rigidity of the casing 110; and a liquid crystal panel 140 disposed on the front surface side of the diffusion plate 130. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device.

  Conventionally, so-called large liquid crystal display devices used for television receivers, monitors, etc., have a diffuser plate, various optical sheets, and a liquid crystal panel in an opening of a box-shaped housing containing a light source such as a cold cathode tube. Is fixed with metal fittings.

  FIG. 7 is an exploded perspective view showing an example of such a conventional liquid crystal display device 300. As shown in the figure, in a conventional liquid crystal display device 300, a cold cathode tube 320 and a side support member 318, which are light sources, are attached to a housing 310, and a rubber cushioning material 333 is provided on the outer periphery of the housing 310. A diffusion plate 330, an optical sheet group 331 such as a prism sheet, and a liquid crystal panel 340 are placed therethrough. The diffusion plate 330, the optical sheet group 331, and the liquid crystal panel 340 are supported so as not to be detached by a support member 370 that is fixed to the housing 310 with screws or the like.

  In the liquid crystal display device having such a structure, the rigidity, in particular, the torsional rigidity must be sufficiently increased in order to prevent the liquid crystal panel from being damaged due to the deformation. Therefore, the housing is made of metal such as a steel plate.

  On the other hand, in a small liquid crystal display device used for portable devices and the like, the liquid crystal panel itself is small and has relatively high rigidity. Can do. And as disclosed in Patent Document 1, there is one in which a liquid crystal panel and a housing are bonded with a double-sided tape or the like.

JP 2005-99221 A

  A liquid crystal display device having a metallic casing is heavy and inconvenient to handle, and causes an increase in transportation costs. In particular, when the size of the liquid crystal panel is increased, in order to ensure sufficient rigidity, the thickness of the metal plate constituting the housing must be increased, and the weight is further increased.

  In addition, the structure in which the housing is bonded to the liquid crystal panel as in the above-described small liquid crystal display device cannot be applied to a large liquid crystal display device. Large liquid crystal display devices have a large thermal expansion when temperature changes occur due to changes in outside air temperature or heat generated during use of the liquid crystal display device, so a glass liquid crystal panel and a metal or synthetic resin housing Is bonded, the liquid crystal display device itself is greatly distorted due to the difference in thermal strain between the two having different linear expansion coefficients.

  The present invention has been made in view of such a viewpoint, and an object thereof is to provide a light-weight and high-rigidity liquid crystal display device.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  (1) A box-shaped synthetic resin housing having an opening on the front surface side, a light source accommodated in the housing, and a composition that is fixed to at least two sides of the outer edge of the opening to increase the rigidity of the housing A liquid crystal display device comprising: a resin diffusion plate; and a liquid crystal panel disposed on a front side of the diffusion plate.

(2) The liquid crystal display device according to (1), wherein a difference in linear expansion coefficient between the synthetic resin constituting the casing and the synthetic resin constituting the diffusion plate is 2.7 × 10 ⁻⁵ K ⁻¹ or less.

  (3) The liquid crystal display device according to (1), wherein the diffusion plate has a thickness of 1 mm or more.

  (4) In (1), a stepped step having at least a first step and a second step provided on the front side of the first step is provided on the outer edge of the opening of the housing. The diffusion plate is fixed to the first stage, and the liquid crystal panel is supported by the second stage.

  (5) The liquid crystal display device according to (1), wherein the liquid crystal panel is slidably supported with respect to the housing.

  (6) The liquid crystal display device according to (1), wherein the rear wall on the back side of the casing has a bellows-like structure that is alternately bent.

  (7) The liquid crystal display device according to (4), further including a circuit board housing portion that houses a circuit board connected to the liquid crystal panel and extending from the second stage to the back side on at least one side of the opening.

  (8) The liquid crystal display device according to (1), further comprising a synthetic resin front plate fixed to an outer edge of the opening on the front side of the liquid crystal panel.

(9) The liquid crystal display device according to (8), wherein a difference in linear expansion coefficient between the synthetic resin constituting the housing and the synthetic resin constituting the front plate is 2.7 × 10 ⁻⁵ K ⁻¹ or less.

  (10) In (8), at least the first stage, the second stage provided on the front side of the first stage, and the front side of the second stage at the opening outer edge of the housing A stepped step having a third step provided on the side is provided, the diffusion plate is fixed to the first step, the liquid crystal panel is supported by the second step, and the front plate is A liquid crystal display device fixed to the third stage.

  (11) The liquid crystal display device according to (8), wherein the liquid crystal panel is slidably supported with respect to the housing.

  (12) In the liquid crystal display device according to (8), the rear wall on the back side of the casing has a bellows-like structure that is alternately bent.

  (13) The liquid crystal display device according to (10), further including a circuit board housing portion that houses a circuit board connected to the liquid crystal panel and extending from the second stage to the back side on at least one side of the opening.

  According to the invention disclosed in the present application as described above, a liquid crystal display device that is lightweight and has high rigidity can be provided.

1 is a cross-sectional perspective view of a liquid crystal display device according to a first embodiment of the present invention. It is an expansion perspective view of the A section in FIG. It is an expansion perspective view of the B section in FIG. It is a perspective view which shows the model of the housing | casing in which the diffusion plate is being fixed, and the housing | casing which is not being fixed. It is the front view which extracted and showed only the housing | casing and diffusion plate in the liquid crystal display device of 1st Embodiment. It is a cross-sectional perspective view of the liquid crystal display device which concerns on the 2nd Embodiment of this invention. It is a disassembled perspective view which shows an example of the conventional liquid crystal display device.

  A first embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional perspective view of a liquid crystal display device 100 according to the first embodiment of the present invention. In the figure, a casing 110 made of synthetic resin, a light source 120 which is a cold cathode tube, a diffusion plate 130 made of synthetic resin, a liquid crystal panel 140, a front plate 150, a circuit board 160 and a control board 161 are shown.

  The housing 110 is made of synthetic resin, and the material thereof is PC (polycarbonate). In addition to PC, ABS (acrylonitrile-butadiene-styrene copolymer resin), PC-ABS (polymer alloy of PC and ABS) and the like can be suitably used, and glass fiber and carbon are used to increase the strength. You may use the fiber reinforced resin which mixed the fiber etc. The housing 110 has a box shape with an opening on the front side (upward in the figure), and the rear wall 111 located on the back side has a bellows-like structure that bends alternately as shown. Is formed. Such a structure increases the rigidity of the housing 110. However, the rear wall 111 may not be provided with a bellows structure but may be a simple flat plate shape. Further, a stepped step 112 is provided at the periphery of the opening of the housing 110, and the diffusion plate 130, the liquid crystal panel 140, and the front plate 150 are supported or fixed on the stepped step 112. Further, at least one side of the peripheral edge of the opening of the housing 110 is provided with a housing portion 113 for housing the circuit board 160 connected to the liquid crystal panel 140. The circuit board 160 is connected to the side of the liquid crystal panel 140 via a flexible board, and is usually provided on two adjacent sides of the liquid crystal panel 140. However, the circuit board 160 may be provided only on one side of the liquid crystal panel 140 or may be provided on two opposite sides. Further, an electronic circuit on the circuit board 160 may be formed on a glass substrate of the liquid crystal panel 140, which is a so-called system-on-glass structure. In that case, the circuit board 160 and the housing portion 113 are not necessary. In the present embodiment, circuit boards 160 are provided so as to be adjacent to the upper side of the illustrated liquid crystal panel 140 and the right side of the liquid crystal panel (not shown). The accommodating portion 113 is also provided on two adjacent sides of the housing 110 corresponding to the circuit board 160.

  The light source 120 is a cold cathode tube, and a necessary number of light sources 120 are arranged at regular intervals so that uniform brightness can be obtained over the entire screen of the liquid crystal display device 100. The light source 120 is not limited to a cold cathode tube, and appropriate known illumination such as a hot cathode tube or a light emitting diode can be used.

  The diffuser plate 130 is made of a synthetic resin having translucency, and has a function of irregularly reflecting or refracting the light emitted from the light source 120 to obtain uniform surface emission. Here, the material is PC in which beads made of glass or synthetic resin are dispersed as a diffusing material. In addition to PC, PMMA (polymethyl methacrylate), PS (polystyrene), MS (styrene-methyl methacrylate resin), and the like can also be used. Further, instead of using a diffusing material, a surface structure such as a groove or a dimple may be formed on the surface of the diffusing plate 130 to diffuse light from the light source 120.

  Here, unlike the diffusion sheet or film used in the above-described small liquid crystal display device, the diffusion plate 130 is a rigid plate material. The reason why the diffusion plate 130 needs rigidity is that the distance between the light source 120 and the diffusion plate 130 and the distance between the liquid crystal panel 140 and the diffusion plate 130 must be kept constant in order to obtain uniform surface light emission. is there. Specifically, the thickness of the diffusion plate 130 is preferably 1 mm or more, and more preferably 1.5 to 2.0 mm. Qualitatively, the diffusing plate 130 only needs to have rigidity enough to be self-supporting without being bent when leaning against a vertical wall.

  The liquid crystal panel 140 corresponds to a pixel in which a TFT substrate in which a large number of TFT (Thin Film Transistor) and electrodes are formed on a glass substrate and a thin film of three colors of red, blue, and green are formed on the glass substrate. It has a well-known structure in which a liquid crystal is sandwiched between color filter substrates formed in this manner, and linearly polarizing plates are pasted on both sides. Note that there are various liquid crystal driving methods such as TN (Twisted Nematic), VA (Vertical Alignment), IPS (In Plane Switching), and any method may be adopted. The liquid crystal panel 140 is described as an example capable of full color display here, but may be a liquid crystal panel with a single color display. The liquid crystal panel 140 in the present embodiment employs an IPS system and can perform full color display.

  The front plate 150 is a transparent synthetic resin plate, and PC, PMMA, PS, MS, or the like can be suitably used as the material thereof. In this embodiment, it is a PC. The front plate 150 is not necessarily required. For example, the front plate 150 serves to protect the liquid crystal panel 140 by restricting bending of the liquid crystal panel 140 during transportation or preventing an external object from colliding with the liquid crystal panel 140. This is effective when the liquid crystal display device 100 is large as in this embodiment. The thickness and rigidity of the front plate 150 can be determined as appropriate, but may be the same as those of the diffusion plate 130 described above.

  As described above, the circuit board 160 is provided on the side of the liquid crystal panel 140 and connected to the drain line and the gate line of the liquid crystal panel 140 via the flexible board. In general, the circuit substrate 160 connected to the drain line is called a drain substrate, and the substrate connected to the gate line is called a gate substrate. The circuit board 160 is further connected to the control board 161 via a flexible board. A video signal input to the liquid crystal display device 100 is converted into a signal input to the circuit board 160 by a driver IC on the control board 161. In the present embodiment, as illustrated, the control board 161 is disposed on the back surface of the housing 110.

  FIG. 2 is an enlarged perspective view of a portion A in FIG. As shown in the figure, the casing 110 has a stepped step 112 formed of a first step 114, a second step 115, and a third step 116 at the outer edge of the opening. The first step 114 is formed on the innermost side of the casing 110, that is, the back side, and the second step 115 and the third step 116 are formed in order from the first step 114 toward the front side. .

  A diffusion plate 130 is placed on the first stage 114 and fixed. The fixing method of the housing 110 and the diffusion plate 130 is a method of fixing the housing 110 and the diffusion plate 130 so that they cannot slide with each other. Examples of these methods include adhesion using a double-sided pressure-sensitive adhesive tape, adhesion using an adhesive, ultrasonic welding, heat fusion, and screwing. In the present embodiment, both are bonded by a double-sided adhesive tape. Various optical sheets 131 such as a prism sheet and a brightness enhancement film are placed on or attached to the front surface of the diffusion plate 130. Whether or not these optical sheets 131 are fixed to the diffusion plate 130 may be appropriately determined as necessary.

  Further, the liquid crystal panel 140 is placed on the second stage 115, and the housing 110 and the liquid crystal panel 140 are supported to be slidable with respect to each other. This is to absorb the difference in thermal strain caused by the difference in linear expansion coefficient when the temperature changes, which is caused by the difference in material between the casing 110 and the liquid crystal panel 140. In addition, in order to absorb an impact or vibration due to an external force applied to the housing 110, it is desirable to support the liquid crystal panel 140 via an elastic buffer material. In the present embodiment, as such a support method, a first cushioning material 141 made of rubber or foam is disposed on the second stage 115, and the liquid crystal panel 140 is placed thereon. The liquid crystal panel 140 is supported by being sandwiched from the front by a second cushioning material 151 made of rubber or foam, which is also attached to the back of the face plate 150. In this case, the displacement when the casing 110 and the liquid crystal panel 140 are expanded and contracted due to the temperature change is caused by the liquid crystal panel 140 and the first buffer material 141 and the second buffer material 151 sliding on each other, or The first buffer material 141 and the second buffer material 151 are absorbed by elastic deformation, and the liquid crystal display device 100 itself is not distorted.

  A front plate 150 is fixed to the third stage 116. The fixing method of the housing 110 and the front plate 150 is desirably a method of fixing the case 110 and the front plate 150 so as not to be slidable with respect to each other like the diffusion plate 130. Examples of such methods include adhesion with a double-sided pressure-sensitive adhesive tape, adhesion with an adhesive, ultrasonic welding, heat fusion, screwing, and the like. In the present embodiment, both are bonded by a double-sided adhesive tape. In addition, the above-described second buffer material 151 is attached to the back surface of the diffusion plate 130 with a double-sided adhesive tape, an adhesive, or the like.

  As described above, the rear wall 111 of the housing 110 has a bellows-like structure that bends alternately. That is, a bent portion having a mountain shape and a valley shape facing the front surface of the liquid crystal display device 100 is alternately provided. The direction of the bent portion is not particularly limited. However, when the liquid crystal display device 100 is large, the bending rigidity particularly in the long side direction is reduced. Therefore, the bent portion extends in parallel with the long side direction of the liquid crystal display device 100. Is preferably arranged. A reflection sheet 121 that reflects light is provided along the inner surface of the rear wall 111, and a light source 120 is provided at a position corresponding to the valley of the bent portion of the rear wall 111 when viewed from the front side of the liquid crystal display device 100. It is done. In this way, the light emitted from the light source 120 can be efficiently reflected to the front side of the liquid crystal display device 100.

  In addition, it may replace with the reflective sheet | seat 121 and may perform appropriate processes, such as plating or a coating, on the inner surface of a rear wall, and may form the reflective surface which reflects light. Further, the bellows-like structure of the rear wall 111 is not essential, and may be a simple flat plate shape if not necessary. Further, the number of steps of the stepped step 112 is not limited to three, and more steps may be formed, or a staircase is provided as a structure in which the diffusion plate 130, the liquid crystal panel 140, and the front plate 150 are attached to the housing 110. A structure other than the step 112 may be used. However, the use of the stepped step 112 is advantageous in terms of manufacturing and cost because an additional member is unnecessary and the casing 110 can be easily molded.

  FIG. 3 is an enlarged perspective view of a portion B in FIG. As shown in FIG. 2, a stepped step 112 including a first step 114, a second step 115, and a third step 116 is formed on the outer edge of the opening of the housing 110. A housing portion 113 extending in the rear surface direction of the housing 110 is formed from the second stage 115, and a circuit board 160 is housed therein. The liquid crystal panel 140 and the circuit board 160 supported by being sandwiched and supported by the first buffer material 141 and the second buffer material 151 on the second stage 115 are a first flexible substrate extending from the TFT substrate of the liquid crystal panel 140. 162 is connected. Further, a second flexible board 163 extends from the circuit board 160 to the back surface of the housing 110 and is connected to a control board 161 fixed to a boss 117 formed on the rear wall 111.

  In addition, the installation position of the control board 161 is not limited to the back surface of the housing as in the present embodiment, and may be an arbitrary position. The control board 161 may be housed in the housing portion 113 like the circuit board 160.

  With such a configuration, the rigidity of the casing 110, in particular the torsional rigidity, is remarkably improved due to the fact that the casing 110 and the diffusion plate 130 are fixed to each other so as not to slide. This will be described using the simplified model shown below as an example.

  FIG. 4 is a perspective view showing models of the case 110a to which the diffusion plate is fixed and the case 110b not to be fixed. In the figure, the model shown in (a) is a casing 110a to which the diffusion plate 130a is fixed, and the model shown in (b) is the casing 110b to which the diffusion plate is not fixed. Here, in order to explain the mechanism for improving the torsional rigidity in an easy-to-understand manner, the model is simplified, and the casings 110a and 110b have a simple rectangular parallelepiped shape with one surface opened. The model (a) is obtained by immobilizing a diffusion plate 130a having the same size as the opening in the opening of the housing 110a so as not to be slid, and imitates the liquid crystal display device according to the present invention. The model (b) is obtained by immovably fixing a square-shaped opening plate 132b having a rectangular central opening to the opening of the housing 110b, and imitating a liquid crystal display device according to the prior art. is there. The aperture plate 132b corresponds to a metal fitting or the like for fixing the liquid crystal panel in the liquid crystal display device of the prior art. The shapes of the housing 110a and the housing 110b are the same, and all the materials including the diffusion plate 130a and the opening plate 132b are the same. The dimensions of model (a) and model (b) both assume a 32-inch television receiver, and the dimensions of each part are shown in the figure. The unit of dimensions is all mm, and the thickness of all parts is 2 mm. In addition, portions hidden behind the diffusion plate 130a and the opening plate 132b and invisible are shown by broken lines for easy understanding.

For the model (a) and model (b) described above, the torsional rigidity GI _p in the long side direction is obtained. Note that the torsional rigidity GI _p in the long side direction indicates the magnitude of resistance to the force to twist in the direction indicated by the arrow in FIG. Here, G is the transverse elastic modulus (unit: N / mm ² ) of the material, and I _p is the cross-sectional secondary pole moment with respect to the centroid on which the torsion torque acts (unit: mm ⁴ ). The long side lengths of the models (a) and (b) in FIG. 4 are 732.76 mm, the total height is 24.6 mm, the plate thickness is 2 mm, and the width of the opening in the model (b) Is 700 mm, the cross-sectional secondary pole moment I _{p (a)} of the model ( _a) and the cross-sectional secondary pole moment I _{p (b)} of the model _(b) are calculated as follows.
I _{p (a)} = 14.6 × 10 ⁷ mm ⁴
I _{p (b)} = 8.84 × 10 ⁷ mm ⁴
Here, since it is assumed that the materials of the model (a) and the model (b) are the same, the transverse elastic modulus G, which is a material constant, is the same value, and the torsional rigidity GI _{p (a) of} each model is the same. When calculating the ratio of GI _{p (b)} ,
GI _{p (a)} ÷ GI _{p (b)} = I _{p (a)} ÷ I _{p (b)} = 1.65
Thus, it can be seen that the model (a) has a torsional rigidity 1.65 times that of the model (b).

  That is, the torsional rigidity is remarkably improved by fixing the diffusing plate 130a having no opening to the casing 110a so as not to slide with respect to each other. As a result, sufficient torsional rigidity can be obtained even when a material having a low strength is used for the housing 110a, so that the housing 110 can be made of a synthetic resin, and its weight is greatly reduced.

  The effect of increasing the rigidity of the casing 110 cannot be obtained unless the rigidity of the diffusion plate 130 itself is high to some extent. That is, as the diffusion plate 130, a material that hardly has rigidity and is easily deformed, such as a diffusion sheet or film used in a small liquid crystal display device, is not suitable.

  Next, the position where the diffusion plate 130 is fixed will be described. FIG. 5 is a front view showing only the casing 110 and the diffusion plate 130 in the liquid crystal display device 100 of the present embodiment. The casing 110 and the diffusion plate 130 can be fixed on the four sides of the upper side 133, the right side 134, the lower side 135, and the left side 136, which are the peripheral edges of the diffusion plate 130 shown in FIG.

  Here, in order to maximize the rigidity of the casing 110, it is obvious that the casing 110 and the diffusion plate 130 should be fixed to each other so as not to be slidable on all four sides of the upper side 133, the right side 134, the lower side 135, and the left side 136. It is. However, since it is possible to obtain the effect of increasing the rigidity of the casing 110 by fixing any two sides, for example, the upper side 133 and the lower side 135 which are two opposite sides, not all four sides, it is practically sufficient. If rigidity can be obtained, it is preferable to fix at least two sides of the peripheral side of the diffusion plate 130. In other words, the diffusion plate 130 may be fixed to at least two sides of the outer edge of the housing 110.

  The temperature of the liquid crystal display device 100 changes due to changes in the outside air temperature such as during the day and night, or in the summer and winter, and heat generated when the liquid crystal display device 100 is used. At this time, in the present embodiment, the housing 110 and the diffusion plate 130 are fixed so as not to be slidable with each other. It will distort itself. In order to avoid this, the linear expansion coefficients of the materials of the casing 110 and the diffusion plate 130 should be close.

  In an actual product, when a temperature change of ± 40K occurs with respect to the temperature at the time of assembling the liquid crystal display device 100 (normal temperature is 20 ° C.), the difference in dimensional change between the casing 110 and the diffusion plate 130 is If it is about 0.8 mm or less, a big problem will not arise. The difference in dimensional change is preferably smaller, preferably 0.5 mm or less, more preferably 0.3 mm or less.

In order to make the difference in dimensional change below the above value with respect to a temperature change of ± 40K, it is preferable to select a material having a linear expansion coefficient close to some extent as the material of the casing 110 and the diffusion plate 130. Here, assuming a 32-inch television receiver having a long side length of 736.76 mm, the linear expansion coefficient of the material of the casing 110 and the diffusion plate 130 for making the difference in dimensional change 0.8 mm or less. The difference Δα _0.8 is
Δα _0.8 = 0.8 ÷ 737.76 ÷ 40 = 2.7 × 10 ⁻⁵ K ⁻¹
The difference in linear expansion coefficient Δα _0.5 and the difference Δα _0.3 in which the difference in dimensional change is 0.5 mm or less and 0.3 mm or less are
Δα _0.5 = 0.5 ÷ 737.76 ÷ 40 = 1.7 × 10 ⁻⁵ K ⁻¹
Δα _0.3 = 0.3 ÷ 736.76 ÷ 40 = 1.0 × 10 ⁻⁵ K ⁻¹
It becomes. Therefore, the difference in coefficient of linear expansion between the material of the casing 110 and the diffusion plate 130 is 2.7 × 10 ⁻⁵ K ⁻¹ or less, preferably 1.7 × 10 ⁻⁵ K ⁻¹ or less, more preferably 1. 0 × 10 ⁻⁵ K ⁻¹ or less.

The above discussion on torsional rigidity and the discussion on the linear expansion coefficient apply not only to the diffusion plate 130 but also to the front plate 150 in exactly the same manner. Therefore, if the front plate 150 is also fixed to be non-slidable at least at the two peripheral edges of the case 110, the rigidity of the case 110 is remarkably improved, and the linear expansion coefficient of the material of the front plate 150 and the case 110 is increased. The difference is 2.7 × 10 ⁻⁵ K ⁻¹ or less like the diffusion plate 130, preferably 1.7 × 10 ⁻⁵ K ⁻¹ or less, more preferably 1.0 × 10 ⁻⁵ K ⁻¹ or less. Then, distortion of the liquid crystal display device 100 due to temperature change can be avoided.

  FIG. 6 is a cross-sectional perspective view of a liquid crystal display device 200 according to the second embodiment of the present invention. This embodiment differs from the first embodiment only in that the liquid crystal panel 140 is supported by the support member 270 without using the front plate 150, and the other points are the same. Therefore, in FIG. 6, the same members as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the present embodiment, the support member 270 is a square-shaped flat plate having an open center. The material is not particularly limited, such as metal, synthetic resin, glass, and wood. In this embodiment, it is PMMA which is a synthetic resin. The support member 270 is for supporting the liquid crystal panel 140 from the front side so that the liquid crystal panel 140 does not fall off. The support member 270 is fixed to the casing 110 by an appropriate method such as adhesion, welding, screwing, or snapping at the outer edge. It is preferable to attach a cushioning material to the position where the support member 270 supports the liquid crystal panel 140, like the front plate 150 in the first embodiment.

  In this embodiment, since there is no front plate 150 in the first embodiment, it is inferior to the first embodiment in terms of protection of the liquid crystal panel 140, but the weight corresponding to the front plate 150 can be reduced, and the front plate 150. Since there is no reflection or absorption of light, there is an advantage that the light use efficiency of the liquid crystal display device 200 is increased and the optical design for antireflection processing is facilitated. This is effective when the protection of the liquid crystal panel 140 is not necessary so much and the rigidity of the casing 110 can be sufficiently secured only by the diffusion plate 130.

  The support member 270 is not limited to the square-shaped flat plate shown here, and may have any shape as long as it can support the liquid crystal panel 140. Further, the support member 270 is not limited to a single member. For example, a plurality of metal fittings that respectively support a plurality of locations around the liquid crystal panel 140 may be used as the support member 270.

  DESCRIPTION OF SYMBOLS 100 Liquid crystal display device, 110, 110a, 110b Case, 111 Rear wall, 112 Stepped step, 113 Housing part, 114 1st stage, 115 2nd stage, 116 3rd stage, 117 Boss, 120 Light source , 121 Reflective sheet, 130, 130a Diffuser plate, 131 Optical sheet group, 132b Aperture plate, 140 Liquid crystal panel, 141 First buffer material, 150 Front plate, 151 Second buffer material, 160 Circuit board, 161 Control board, 162 first flexible substrate, 163 second flexible substrate, 200 liquid crystal display device, 270 support member, 300 liquid crystal display device, 310 housing, 318 side support member, 320 cold cathode tube, 330 diffusion plate, 331 optical sheet Group, 333 cushioning material, 340 liquid crystal panel, 370 support member.

Claims (13)

A box-shaped synthetic resin housing having an opening on the front side;
A light source housed in the housing;
A synthetic resin diffusion plate fixed to at least two sides of the outer edge of the opening and increasing the rigidity of the housing;
A liquid crystal panel disposed on the front side of the diffusion plate;
A liquid crystal display device. 2. The liquid crystal display device according to claim 1, wherein a difference in linear expansion coefficient between the synthetic resin constituting the housing and the synthetic resin constituting the diffusion plate is 2.7 × 10 ⁻⁵ K ⁻¹ or less. The liquid crystal display device according to claim 1, wherein the diffusion plate has a thickness of 1 mm or more. The outer edge of the opening of the housing is provided with a stepped step having at least a first step and a second step provided on the front side of the first step,
The diffusion plate is fixed to the first stage;
The liquid crystal display device according to claim 1, wherein the liquid crystal panel is supported by the second stage. The liquid crystal display device according to claim 1, wherein the liquid crystal panel is slidably supported with respect to the housing. The liquid crystal display device according to claim 1, wherein a rear wall on the back side of the housing has a bellows-like structure that is alternately bent. 5. The liquid crystal display device according to claim 4, further comprising a circuit board housing portion that houses a circuit board connected to the liquid crystal panel and extending from the second stage to the back side on at least one side of the opening. The liquid crystal display device according to claim 1, further comprising a synthetic resin front plate fixed to an outer edge of the opening on a front side of the liquid crystal panel. The liquid crystal display device according to claim 8, wherein a difference in coefficient of linear expansion between the synthetic resin constituting the housing and the synthetic resin constituting the front plate is 2.7 × 10 ⁻⁵ K ⁻¹ or less. The outer edge of the opening of the housing has at least a first stage, a second stage provided on the front side of the first stage, and a third stage provided on the front side of the second stage. A stepped step having a step is provided,
The diffusion plate is fixed to the first stage;
The liquid crystal panel is supported by the second stage,
The liquid crystal display device according to claim 8, wherein the front plate is fixed to the third stage. The liquid crystal display device according to claim 8, wherein the liquid crystal panel is slidably supported with respect to the housing. The liquid crystal display device according to claim 8, wherein a rear wall on the back side of the housing has a bellows-like structure that is alternately bent. 11. The liquid crystal display device according to claim 10, further comprising a circuit board housing portion that houses a circuit board connected to the liquid crystal panel and extending from the second stage to the back side on at least one side of the opening.

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