WO2006080201A1

WO2006080201A1 - Liquid crystal display device

Info

Publication number: WO2006080201A1
Application number: PCT/JP2006/300440
Authority: WO
Inventors: Motoji Egawa; Hiroshi Johmen
Original assignee: Minebea Co., Ltd.
Priority date: 2005-01-27
Filing date: 2006-01-16
Publication date: 2006-08-03
Also published as: TW200702817A

Abstract

A wall (18a) in parallel to a side end face of a light guide plate (20) is set up in a light source installation space (S), from an aluminum heat radiation plate (18), the light source installation space (S) being provided along a frame body (14a) of one side of a resin frame (12), the heat radiation plate (18) being laid on the surface of a floor plate (16) of the resin frame (12). LEDs (36) mounted on an FPC (34) are fixed on the surface of the wall (18a) in a tightly contacting manner. A cut and bent up section (30a) formed at a shield cover (30) penetrates through a through-hole (16a) to be in an intimate contact with the wall (18a), where the through-hole (16a) is provided in the floor plate (16) of the resin frame (14). As a result, heat exchange can be made between the aluminum heat radiation plate (18) and the shield cover (30). Accordingly, heat from the LEDs (36) is released to the outside of a liquid crystal display device (32) through each section of the wall (18a), aluminum heat radiation plate (18), cut and bent up section (30a), and shield cover (30).

Description

Specification

Liquid crystal display

Technical field

The present invention relates to an improvement of a liquid crystal display device provided with a sidelight type planar illumination device.

Background art

[0002] Liquid crystal display devices are widely used as display means of today's electronic devices, but since this liquid crystal display device is not self-luminous, it is necessary to ensure visibility at night or in dark places. The lighting means is necessary. Conventionally, planar illumination devices have been used as such illumination means.

Further, as one form of the planar lighting device, a sidelight type planar lighting device is widely used. A side-light type planar illumination device is composed of a light guide plate having translucency and a rod-like light source such as a fluorescent tube arranged on a side end surface of the light guide plate (for example, Patent Document 1). ). As a recent trend, a planar lighting device having a point light source capable of simplifying a drive circuit is used due to an increase in applications to small electronic devices such as portable information terminals. (For example, refer to Patent Document 2.) ₀

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2003-338214 ([0013] to [0017], [0022])

Patent Document 2: Japanese Patent Laid-Open No. 2004-186004 ([Claim 1], FIG. 2)

Disclosure of the invention

Problems to be solved by the invention

[0004] By the way, a surface illumination device for a liquid crystal display device having a relatively large display area, which is used for stationary equipment such as industrial machines and car navigation systems, needs to illuminate a wide area with high brightness. A fluorescent tube is generally used as the primary light source. An example of the structure of the liquid crystal display device 10 is shown in FIG.

In the liquid crystal display device 10, an aluminum heat sink 18 is laid on the surface of the floor plate 16 of the resin frame 12 having the frame 14 and the floor plate 16 surrounded by the frame 14 together with a reflection sheet (not shown). On the aluminum heat sink 18, light of a certain width along the frame 14a on one side of the resin frame 12 With the light source installation space secured, the light guide plate 20 and optical sheets (not shown) are installed one on top of the other, and the fluorescent tube 22 extends along the side edge of the light guide plate 20 in the light source installation space. Is arranged. Further, a liquid crystal panel 24 is overlaid on the frame body 14 of the resin frame 12. On the other hand, a circuit board 26 for driving the liquid crystal panel 24 and the like is fixed to the back surface of the floor plate 16 of the resin frame 12. The liquid crystal panel 24 side force of the resin frame 12 is covered with a face cover 28 having an opening 28a for the liquid crystal panel 24, and from the circuit board 26 side, the electromagnetic shielding of the circuit board 26 is secured. A shield cover 30 for covering each of the parts is put on and each part is integrally formed.

[0005] In this liquid crystal display device 10 as well, the fluorescent tube 22 as a light source is an LED (white color) excellent in environmental resistance and impact resistance, as in the case of a liquid crystal display device having a relatively small display area. In order to obtain the same amount of light as that of the fluorescent tube 22, it is necessary to increase the current supplied to the LED or to use a large number of LEDs. Both of these configurations cause an increase in the amount of heat generated by the LED power accompanying an increase in the power consumption of the LED, resulting in conflicting problems such as a significant reduction in the luminous efficiency of the LED. .

Therefore, in order to replace the fluorescent tube 22 with the LED in the liquid crystal display device 10 with a relatively large display area, the entire structure of the liquid crystal display device 10 is changed drastically and the heat dissipation measures of the LED are fully implemented. It was indispensable. Such an increase in cost due to the change in the overall structure of the liquid crystal display device 10 negates the cost reduction effect of replacing the light source with the fluorescent tube power by the LED itself, and in some cases exceeds it. It was.

[0006] The present invention has been made in view of the above problems, and an object of the present invention is to provide a sufficient illumination capability for a sidelight type planar illumination device in a liquid crystal display device having a relatively large display area. It is necessary to ensure the cost reduction by replacing the fluorescent tube, which is the light source, with the LED, and to reduce the heat dissipation of the LED.

Means for solving the problem

[0007] In order to solve the above problems, a planar lighting device according to the present invention has a liquid crystal panel and a sidelight type planar lighting device and a circuit board positioned with a resin frame interposed therebetween. And a liquid crystal display device having a structure in which a shield cover is put on each side of the circuit board, and the respective parts are integrated together. The oil frame has a frame body and a floor plate surrounded by the frame body, and an aluminum heat sink is laid on the surface of the floor plate, and on one side of the grease frame on the aluminum heat sink plate. The light guide plate of the planar lighting device is installed in a state where a light source installation space of a certain width is secured along the frame body, and the liquid crystal panel is overlaid on the frame body of the resin frame. In addition, a circuit board is fixed to the rear surface of the floor plate, and a wall parallel to the side end surface of the light guide plate is disposed on the side of the light guide plate at a portion facing the light source installation space of the aluminum radiator plate. Standing up a predetermined distance from the end face, A plurality of LEDs mounted on the FPC are closely attached and fixed to the side wall surface of the light guide plate via the FPC in a state of being opposed to the side end surface of the light guide plate, and the shield frame is attached to the shield cover. A cut-and-raised portion that penetrates through the floor plate and comes into close contact with the portion of the aluminum heat sink that faces the light source installation space is formed, and the cut-and-raised portion formed on the shielding force bar penetrates the floor plate of the resin frame. A through hole is formed.

According to the present invention, the liquid crystal panel and the sidelight type planar lighting device and the circuit board are positioned across the resin frame, and the face cover is arranged from the liquid crystal panel side of the resin frame to the circuit board. From the aluminum heat sink laid on the floor plate surface of the resin frame of the liquid crystal display device having a structure in which the side covers are respectively covered with the shield covers and the parts are integrated, the frame on one side of the resin frame A wall parallel to the side end surface of the light guide plate is erected at a predetermined distance from the side end surface of the light guide plate in a light source installation space of a constant width provided along the light guide plate side wall surface of the light guide plate. In addition, a plurality of LEDs mounted on the FPC are in close contact with and fixed to the side end face of the light guide plate through the FPC, so that the light guide plate is illuminated by the LEDs. Also, in the light source installation space, the LED support means is constituted by the wall, and the heat of the LED is transmitted to the wall, so that the wall also functions as the LED heat dissipation means. Also, the cut and raised formed in the shield force bar is brought into close contact with the wall through the through hole in the floor plate of the resin frame, so that the aluminum heat sink and the shield cover are in physical contact with each other. Aluminum heat sink and Heat exchange with the first cover becomes possible. Therefore, the heat of the LED is dissipated to the outside of the liquid crystal display device through each part of the wall, the aluminum heat sink, the cut and raised shield cover, and the LED is cooled.

The LED cooling effect can also be obtained by discharging the heat of the LED trapped in the light source installation space from the through-hole formed in the floor plate of the resin frame.

[0009] In the present invention, the wall of the aluminum heat radiating plate that is erected in the light source installation space is such that the end of the aluminum heat radiating plate stands up in a wall shape. Therefore, the wall is integrated with the aluminum heat sink. Therefore, the heat of the LED is smoothly transferred to the aluminum heat sink, and the LED heat is further cut and raised, dissipated to the outside of the liquid crystal display device via each part of the shield cover, and the LED is cooled. .

[0010] Further, in the planar lighting device according to the present invention for solving the above-described problems, the liquid crystal panel and the sidelight type planar lighting device and the circuit board are positioned with the resin frame interposed therebetween. And a liquid crystal display device having a structure in which the liquid crystal panel side force face cover of the resin frame is covered with a shield cover, such as a circuit board side cover, and the parts are integrated. The resin frame includes a frame body and a floor plate surrounded by the frame body, and an aluminum heat sink is laid on the surface of the floor plate, and one side of the resin frame is disposed on the aluminum heat sink plate. The light guide plate of the planar lighting device is installed in a state where a light source installation space of a certain width is secured along the frame body, and a liquid crystal panel is overlaid on the frame body of the resin frame. In addition, a circuit board is fixed to the back surface of the floor board. The wall of the aluminum radiator plate facing the light source installation space is parallel to the side end surface of the light guide plate and has a higher thermal conductivity than the material of the aluminum radiator plate. A plurality of LEDs mounted on the FPC are arranged opposite to the side end surface of the light guide plate. In this state, it is fixed in close contact via the FPC, and the shield cover penetrates the floor plate of the resin frame and forms a cut-out that closely contacts the portion of the aluminum heat sink that faces the light source installation space. In addition, a through hole is formed in the floor plate of the resin frame, through which a cut and raised formed in the shield cover passes.

[0011] According to the present invention, the liquid crystal panel and the surface of the sidelight system are sandwiched between the resin frames. And the circuit board is positioned, the face cover is covered from the liquid crystal panel side of the resin frame, and the shield cover is also put on the circuit board side force, so that the respective parts are integrated. From the aluminum heat sink laid on the surface of the floor of the resin frame of the liquid crystal display device to the light source installation space of a certain width along the frame on one side of the resin frame, the side end face of the light guide plate A wall made of a metal that is parallel and has a higher thermal conductivity than the material of the aluminum heat sink is erected with a predetermined distance from the side end face of the light guide plate, and on the side wall surface of the light guide plate of the wall, A plurality of LEDs mounted on the FPC are closely fixed via the FPC in a state of being opposed to the side end face of the light guide plate, so that the light guide plate is illuminated by the LEDs. Also, in the light source installation space, the LED support means is constituted by the wall, and the heat of the LED is transmitted to the wall, so that the wall also functions as the LED heat dissipation means. Also, the cutting and raising formed on the shield cover penetrates through the through hole in the floor plate of the resin frame and comes into close contact with the aluminum heat sink with the wall fixed, so that the aluminum heat sink and the shield cover are physically connected. Heat exchange between the wall, aluminum heat sink, and shield cover. Therefore, the heat of the LED is dissipated to the outside of the liquid crystal display device through the walls, the aluminum heat sink, the cut and raised parts, and the LED is cooled.

However, the wall has a higher thermal conductivity than the material of the aluminum heat sink and is made of metal, so the cooling effect of the LED through the wall is further enhanced.

In the present invention, it is desirable that the wall fixed to the portion of the aluminum heat radiating plate facing the light source installation space is composed of a prismatic member having a thickness greater than that of the aluminum heat radiating plate. .

According to this configuration, the high thermal conductivity of the wall allows the heat of the LED to be absorbed sufficiently by the wall and allows the LED to be efficiently cooled. In addition, as a method of fixing the wall to the aluminum heat sink, not only adhesion but also screwing can be performed using the thickness of the prismatic member.

The invention's effect [0013] Since the present invention is configured as described above, in a liquid crystal display device having a relatively large display area, a fluorescent tube as a light source is used as an LED while ensuring the illumination capability required for a sidelight type planar illumination device. It is possible to realize cost reduction by replacing and LED heat dissipation measures.

Brief Description of Drawings

FIG. 1 is an exploded view of a liquid crystal display device according to a first embodiment of the present invention.

2 is a plan view showing a state in which the liquid crystal display device shown in FIG. 1 has a face cover and a liquid crystal panel removed.

FIG. 3 is a cross-sectional view taken along line AA in FIG.

4 is a cross-sectional view of a liquid crystal display device according to a second embodiment of the present invention, and shows a cross-sectional view of a portion corresponding to FIG. 3 of the liquid crystal display device according to the first embodiment of the present invention. It is a thing.

FIG. 5 is an exploded view of a conventional liquid crystal display device.

Explanation of symbols

[0015] 12: Grease frame, 14: Frame, 14a: Side frame, 16: Floor plate, 16a: Through hole, 18: Aluminum heat sink, 18a: Wall, 20: Light guide plate, 24: Liquid crystal Panel, 26: Circuit board, 28: Face cover, 28a: Opening, 30: Shield canopy, 30a: Cut up, 32, 38: Liquid crystal display, 34: FPC, 36: LED, S: Light source installation Space

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Here, parts that are the same as or equivalent to those in the prior art are given the same reference numerals.

First, the liquid crystal display device 32 according to the first embodiment of the present invention will be described. As shown in FIGS. 1 to 3, the liquid crystal display device 32 includes a frame 14 and a floor plate 16 surrounded by the frame 14, and the surface of the floor plate 16 has a reflection (not shown) An aluminum heat sink 18 is laid together with the sheet, and on the aluminum heat sink 18, a certain width (a width capable of installing the fluorescent tube 22 in FIG. 5) along the frame 14 a on one side of the resin frame 12. The light guide plate 20 and optical sheets (not shown) are stacked in a state where the light source installation space S is secured. Also, in the light source installation space S, the printed circuit board FPC34 is A plurality of mounted LEDs 36 are arranged to face the side end face of the light guide plate 20. Specifically, a wall 18a parallel to the side end face of the light guide plate 20 is provided at a portion facing the light source installation space S of the aluminum heat radiating plate 18 with a predetermined distance (FPC34 and LED36 from the side end face of the light guide plate 20). A plurality of LEDs 36 are disposed opposite to the side end surface of the light guide plate 20 by adhering and fixing the FPC 34 to the side wall surface of the light guide plate of the wall 18a. It is fixed in the state. The wall 18a erected in the light source installation space S is such that the end of the aluminum heat radiating plate 18 stands up in a wall shape.

Furthermore, a liquid crystal panel 24 is overlaid on the frame body 14 of the resin frame 12. On the other hand, a circuit board 26 for driving the liquid crystal panel 24 and the like is fixed to the back surface of the floor board 16 of the resin frame 12. The liquid crystal panel 24 side of the resin frame 12 is covered with a face cover 28 in which an opening 28a for the liquid crystal panel 24 is formed, and the circuit board 26 side ensures electromagnetic shielding of the circuit board 26. For example, each part is covered with a shield cover 30 and the parts are integrated together. Of the face cover 28 and the shield cover 30, at least the shield cover 30 is a sheet metal part.

Further, the shield cover 30 is formed with a cut-and-raised 30a. The cut-and-raised 30a passes through the floor plate 16 of the resin frame 14 to the surface of the wall 18a formed in the part facing the light source installation space of the aluminum heat sink 18 on the side opposite to the surface to which the FPC 34 is bonded. It is closely attached to. A through hole 16a through which the cut and raised 30a of the shield cover 30 passes is formed in the floor plate 16 of the resin frame 14. Note that the wall 18a and the cut-and-raised 30a may be bonded and fixed by an adhesive having a good thermal conductivity even in a state where they are simply pressed.

By the way, the light source installation space S in the above structure is a space where the fluorescent tube 22 is arranged in the conventional example shown in FIG. 5, and the fluorescent tube 22 that requires a relatively large installation volume is deleted. The space created by this is effectively used to install the LED36. The light guide plate 20, the liquid crystal panel 24, the circuit board 26, and the face cover 28 have the same shape as the conventional example shown in FIG. On the other hand, the resin frame 12, the aluminum heat sink 18, and the shield cover 30 also have only a through hole 16a, a wall 18a, and a cut-and-raised 30a, respectively, added to the conventional shape. By making changes, it becomes possible to mold the required shape. [0019] According to the first embodiment of the present invention having the above-described configuration, the following operational effects can be obtained. First, the aluminum heat dissipation plate 18 laid on the surface of the floor plate 16 of the resin frame 12 is led to the light source installation space S having a constant width provided along the frame body 14a on one side of the resin frame 12. A wall 18a parallel to the side end surface of the light plate 20 is erected with a predetermined distance from the side end surface of the light guide plate 20, and a plurality of LEDs 36 mounted on the FPC 34 are mounted on the wall surface of the wall 18a on the light guide plate side. The light guide plate 20 is illuminated by the LED 36 by being in close contact with and fixed to the side end face of the light guide plate 20 via the FPC 34. Also, in the light source installation space S, the wall 18a constitutes the support means for the LED 36, and the heat of the LED 36 is transferred to the wall 18a, so the wall 18a also functions as a heat dissipation means for the LED 36. .

Also, the cut-and-raised 30a formed in the shield cover 30 penetrates the wall 18a through the through-hole 16a of the floor plate 16 of the grease frame 14 and adheres to the aluminum heat sink 18 with the wall 18a. The metal cover 30 is in physical contact with the aluminum heat sink 18 and the heat exchange between the aluminum heat sink 18 and the shield cover 30 becomes possible. Therefore, the heat of the LED 36 is radiated to the outside of the liquid crystal display device 32 through each part of the wall 18a, the aluminum heat sink 18, the cut and raised 30a, and the shield cover 30, and the LED 36 is efficiently cooled. It will be. As described above, according to the first embodiment of the present invention, the LED 36 can be cooled by actively utilizing the shield cover 30.

[0020] Further, the cooling effect of the LED 36 can also be obtained by discharging the heat of the LED 36 trapped in the light source installation space S from the through hole 16a formed in the floor plate 16 of the resin frame 12. In the first embodiment of the present invention, the wall 18a of the aluminum heat radiating plate 18 standing in the light source installation space S is such that the end of the aluminum heat radiating plate 18 stands up like a wall. Therefore, the wall 18a is integrated with the aluminum heat sink 18. Therefore, the heat of the LED 36 is smoothly transferred from the wall 18a to the aluminum heat sink 18 and further radiated to the outside of the liquid crystal display device 32 through each part of the cut and raised 30a and the shield cover 30. It becomes.

In the simulation calculation example, it was confirmed that the junction temperature of LED36 decreased by 2.7 ° C due to the above cooling effect. Subsequently, a liquid crystal display device 38 according to a second embodiment of the present invention will be described with reference to FIG. Here, the same or corresponding parts as those of the first embodiment of the present invention are denoted by the same reference numerals, and detailed description thereof will be omitted.

The difference between the liquid crystal display device 38 according to the second embodiment of the present invention and the liquid crystal display device 32 according to the first embodiment faces the light source installation space S of the aluminum heat sink 18. A wall 40 made of metal (for example, copper), which is parallel to the side end face of the light guide plate 20 and has a higher thermal conductivity than the material of the aluminum heat sink 18, is located at a predetermined distance from the side end face of the light guide plate 20. The point is that it is fixed with a gap. Therefore, the FPC 34 on which the plurality of LEDs 36 are mounted is fixed to the side wall surface of the light guide plate of the wall 40.

In addition, as shown in FIG. 4, the cut-and-raised 30b formed on the shield cover 30 was bent once at a right angle and then again parallel to the back surface of the aluminum heat sink 18 as shown in FIG. The cut and raised 30b and the aluminum heat sink 18 are in close contact with the back surface of the aluminum heat sink 18.

[0023] Here, since the wall 40 is formed of a prismatic member thicker than the aluminum radiator plate 18, the fixing method of the wall 40 to the aluminum radiator plate 18 is not only adhesion but also a wall that is a prismatic member. It is also possible to perform screwing using a wall thickness of 40. Furthermore, the wall 40, the aluminum heat sink 18, and the cut and raised 30b can all be fixed with screws.

Note that the cut-and-raised 30b of the shield cover 30 has a shape that is bent only once so that it is in close contact with the surface of the wall 40 opposite to the surface to which the FPC 34 is attached. It is also possible to do this.

[0024] According to the second embodiment of the present invention having the above-described configuration, the light guide plate 20 is provided in the light source installation space S having a constant width provided along the frame body 14a on one side of the resin frame 12. A wall 40 made of a metal parallel to the side end face and having a higher thermal conductivity than the material of the aluminum heat sink 18 is erected with a predetermined distance from the side end face of the light guide plate 20, and the wall 40 side of the light guide plate The light guide plate 20 is illuminated by the LED 36 by fixing the plurality of LEDs 36 mounted on the FPC 34 on the wall surface in close contact with the side end surface of the light guide plate 20 via the FPC 34. It becomes. Also, in the light source installation space S, the wall 40 constitutes a support means for the LED 36, and the heat of the LED 36 is transferred to the wall 40. It also functions as a means.

The cut-and-raised 30b force formed on the shield cover 30 also passes through the through hole of the floor plate 16 of the grease frame 12 and comes into close contact with the aluminum heat sink 18 to which the wall 40 is fixed. 18 and the shield cover 30 are in physical contact, and heat exchange between the wall 40, the aluminum heat sink 18, and the shield cover 12 becomes possible. Therefore, the heat of the LED 36 is radiated to the outside of the liquid crystal display device 38 through the wall 40, the aluminum heat radiating plate 16, the cut-and-raised 30b, and the shield cover 30, and the LED 36 is cooled.

In the second embodiment of the present invention, the wall 40 fixed to the portion of the aluminum heat radiating plate 18 facing the light source installation space S is composed of a prismatic member that is thicker than the aluminum heat radiating plate 18. Therefore, the high thermal conductivity of the wall 40 allows the heat of the LED 36 to be sufficiently absorbed by the wall and allows the LED 36 to be efficiently cooled. In the simulation calculation example, it was confirmed that the junction temperature of the LED 36 decreased by 4.0 ° C due to the cooling effect.

In addition, as a method of fixing the wall 40 to the aluminum heat sink 18, not only adhesion but also screwing can be performed using the thickness of the prismatic member. In particular, it is possible to further improve the heat dissipation by screwing all of the wall 40, the aluminum heat sink 18, and the cut and raised 30b together.

In addition, the description of the same operational effects as those of the first embodiment of the present invention is omitted.

Claims

The scope of the claims

[1] A liquid crystal panel and a sidelight type surface illumination device and a circuit board are positioned across a resin frame, and the liquid crystal panel side force of the resin frame is face cover force. A liquid crystal display device having a structure in which shield covers are respectively covered and the components are integrated,

The resin frame includes a frame body and a floor plate surrounded by the frame body. An aluminum heat sink is laid on the surface of the floor board, and one side of the resin frame is placed on the aluminum heat sink plate. A light guide plate of a planar lighting device is installed in a state where a light source installation space of a certain width is secured along the frame body, and a liquid crystal panel is overlaid on the frame body of the resin frame. In addition, a circuit board is fixed to the back surface of the floor board,

A wall parallel to the side end surface of the light guide plate is erected at a portion facing the light source installation space of the aluminum heat sink with a predetermined distance from the side end surface of the light guide plate. A plurality of LEDs mounted on the FPC are closely fixed to the side wall surface of the light guide plate through the FPC in a state of being arranged facing the side end surface of the light guide plate,

The shield cover is formed with a cut-and-raised which penetrates the floor plate of the resin frame and adheres closely to the portion of the aluminum heat radiating plate facing the light source installation space.

A liquid crystal display device, wherein a through-hole through which a cut and raised formed in the shield cover passes is formed in a floor plate of the resin frame.

2. The liquid crystal display device according to claim 1, wherein the wall of the aluminum heat radiating plate that is erected in the light source installation space has an end portion of the aluminum heat radiating plate erected in a wall shape.

[3] The liquid crystal panel and the sidelight type surface illumination device and the circuit board are positioned across the resin frame, and the liquid crystal panel side force of the resin frame is face cover force. A liquid crystal display device having a structure in which shield covers are respectively covered and the components are integrated,

The resin frame has a frame body and a floor plate surrounded by the frame body. An aluminum heat sink is laid on the surface of the floor board, and one side of the resin frame is placed on the aluminum heat sink plate. A light guide plate of a planar lighting device is installed in a state where a light source installation space of a certain width is secured along the frame, and a liquid crystal panel is further stacked on the frame of the resin frame. And a circuit board is fixed to the back surface of the floor board,

The wall of the aluminum heat sink facing the light source installation space is parallel to the side surface of the light guide plate and has a higher thermal conductivity than the material of the aluminum heat sink. It is fixed at a predetermined distance from the side end surface of the light plate, and is attached to the side wall surface of the light guide plate of the wall.

A plurality of LEDs mounted on the FPC are arranged opposite to the side end face of the light guide plate.

, Are closely fixed via the FPC,

4. The liquid crystal display device according to claim 3, wherein a wall fixed to a portion of the aluminum heat radiating plate facing the light source installation space is formed by a prism member having a thickness larger than that of the aluminum heat radiating plate. .