JP2006227073A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device with which heat produced on a light source element and on a driving circuit which is used to make the light source element emit light, is prevented from being transferred to components in the vicinity of the driving circuit. <P>SOLUTION: The liquid crystal display device has such a structure that a heat pipe 10c is disposed in an extended condition along a case, comprising a plate 10b and a rear face plate 10d placed on the rear face of the liquid crystal display device, wherein the heat pipe 10c is in contact with the plate 10b and the rear face plate 10d over a wide range. Based on this structure, in the case the heat produced on an LED circuit 9 is transferred to the heat pipe 10c, the heat is transferred to the wide range of the plate 10b and the rear face plate 10d by using the heat pipe 10c as a heat conduction member. That is, the heat is efficiently transferred up to the rear face of the liquid crystal display device via the heat pipe 10c. Consequently the heat is radiated on the wide range of the plate 10b and the rear face plate 10d, and the heat transferred to the components in the vicinity of the LED circuit 9 is reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device in which light emitted from a light source element is guided to a liquid crystal display side by a member constituting an optical waveguide so that display by a liquid crystal display can be performed. It is suitable for use.

  FIG. 9 shows a cross-sectional view of a liquid crystal display device used in a vehicle display instrument disclosed in Patent Document 1. As shown in this figure, the conventional liquid crystal display device includes a liquid crystal display J1, an optical member J2 such as an optical sheet and a diffusion sheet disposed on the back surface of the liquid crystal display J1, and a light emitting diode ( LED circuit composed of J3 (hereinafter referred to as LED) and a switching element for turning on and off the LED J3, an LED drive circuit unit for controlling the on / off timing of the LED J3 by the LED circuit, and a liquid crystal display A wiring board J4 on which a liquid crystal driving circuit unit used to drive J1 is formed, a light guide plate J5 that constitutes an optical waveguide that guides light emitted from the LED J3, and a reflector that directs light to the surface side of the light guide plate J5 J6 is included.

  In the liquid crystal display device configured as described above, the LED drive circuit unit controls the on / off timing of energization of the LED by the LED circuit, and based on this, light is emitted from the LED J3. After this light is incident from the end surface of the light guide plate J5, the light is guided to the surface of the light guide plate J5 by the reflecting plate J6 provided on the back surface of the light guide plate J5, and the liquid crystal disposed on the surface side of the light guide plate J5. The display device J1 is irradiated with light. Thereby, light is illuminated from the back side of the liquid crystal display J1 driven by the liquid crystal drive circuit unit, and display on the liquid crystal display J1 is performed.

  In this liquid crystal display device, an LED circuit used for driving the LED J3, for example, a switching element in the LED circuit, generates heat when performing liquid crystal display. If the heat generated by the drive circuit is transmitted to the vicinity of the LED circuit and the parts, it will be affected. For example, the light guide plate J5 or the like is made of an acrylic plate or the like and is not high in heat durability. Therefore, there is a problem that the light guide plate J5 is deformed when heat generated by the LED circuit is transmitted. Further, when a portion where an advanced circuit is used, such as the liquid crystal display J1, is affected by heat, there arises a problem that correct drawing cannot be performed.

For this reason, the wiring board J4 on which the LED circuit is formed is composed of a metal heat sink, and this heat sink is structured to extend to the back side of the liquid crystal display device (the back side of the light guide plate). The heat radiating plate is made to function as a cooling module so that heat is radiated from the back surface of the liquid crystal display device.
JP 2004-279262 A

  However, in the above conventional liquid crystal display device, a heat radiating plate as a heat radiating member is directly joined to the drive circuit. For this reason, even if the heat sink is extended to a position far from the drive circuit, the heat resistance of the heat sink is high, and heat is dissipated even while heat is transmitted through the heat sink, and the heat is transmitted to the parts near the drive circuit. Therefore, the above problem cannot be solved sufficiently. In other words, even if the metal plate extends to the back surface of the liquid crystal display device, the heat resistance of the metal plate is high, so that heat cannot be sufficiently transferred to the back surface side of the liquid crystal display device, and in the vicinity of the drive circuit. Heat is mainly dissipated, and the vicinity of the drive circuit becomes particularly hot.

  Here, as shown in FIG. 9, the LED J3 is directly formed on the wiring board J4 on which the drive circuit is formed as a form in which the LED J3 is incorporated in the drive circuit. In some cases, the drive circuit may be separated. In this case, since the LED J3 is also a heat source that generates heat, the LED J3 is also emitted from the LED J3 by mounting the LED J3 on the metal substrate and connecting the heat sink to the metal substrate. Heat is released. For this reason, the same can be said with respect to such a configuration.

  In view of the above, the present invention provides a light source element and a liquid crystal display device capable of preventing heat generated by a drive circuit used to emit light from the light source element from being transmitted to components in the vicinity of the drive circuit. Also aimed.

  In order to achieve the above object, according to the first aspect of the present invention, there are provided a case (10b, 10d) including a back plate (10d) disposed at a position rearward of the liquid crystal display (1) and the optical waveguide (5). A heat transfer member (10c) for transferring heat from the drive circuit (9), the heat transfer member (10c) extending along the back plate (10d) and contacting the back plate (10d) By being configured, the case (10b, 10d) is also used as a heat radiating member.

  As described above, the heat transfer member (10c) is extended along the case including the back plate (10d), and the heat transfer member (10c) is in contact with the back plate (10d) over a wide range. For this reason, when the heat generated by the drive circuit (9) is transmitted to the heat transfer member (10c), the heat can be transmitted over a wide range of the back plate (10d) through the heat transfer member (10c). That is, heat can be efficiently transferred to the back surface of the liquid crystal display device through the heat transfer member (10c).

  For this reason, it is possible to dissipate heat over a wide range of the back plate (10d), and it is possible to reduce heat transmitted to the components in the vicinity of the drive circuit (9). Thereby, it is possible to suppress heat from being transmitted to components in the vicinity of the drive circuit (9), and it is possible to prevent the influence of heat.

  In the case of such a configuration, the case including the back plate (10d) can be used as a heat radiating member, so that it is possible to reduce the number of parts with respect to the parts required for heat dissipation. Become.

  The invention according to claim 2 is characterized in that the heat transfer member (10c) and the drive circuit (9) are configured separately.

  Thus, since the drive circuit (9) and the heat transfer member (10c) can be separated by separating the heat transfer member (10c) and the drive circuit (9), for example, the optical waveguide (5) And the drive circuit (9) alone are assembled, and after making various adjustments based on the inspection results, the heat transfer member (10c) is driven when the drive circuit (9) is newly replaced. It is not necessary to remove the circuit (9), and the complication of work can be avoided.

  The invention described in claim 3 is characterized by having the same structure as that of claim 1 when the heat generated by the light source (8) is dissipated by the heat dissipating member (10d).

  According to such a configuration, even when the light source (8) and the drive circuit (9) are separated, the same effect as in the first aspect can be obtained.

  In the case of the configuration of the invention according to claim 1 or 3, further, as shown in claim 4, the back plate (10d) has a heat radiating member (10e) that is superior in heat dissipation than the heat transfer member (10c). ).

  The invention according to claim 5 is characterized in that the heat dissipating member (10e) is arranged at a height equivalent to or higher than the optical waveguide (5) and the substrate (7).

  By adopting such an arrangement, it is possible to increase the heat dissipation efficiency of the heat dissipation member (10e) and prevent the heated ambient air from moving in the direction of the optical waveguide (5) or the wiring board (7). it can.

  The invention according to claim 6 is characterized in that at least one of a heat pipe, a metal plate, a member including a carbon sheet, a conductive member, and the like is used as the heat transfer member (10c).

  Thus, at least one of a heat pipe, a metal plate, a member including a carbon sheet, a conductive member, and the like can be used as the heat transfer member (10c).

  The invention according to claim 7 is characterized in that the heat dissipating member (10e) is configured by superimposing a plurality of fins in parallel, and the plurality of fins are arranged in parallel with the top-to-bottom direction. .

  If it is set as such a form, it can make it easy to carry out the convection of air so that the surrounding air heated by the heat radiation will be easy to escape from the uppermost position among the radiation fins.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
In the present embodiment, the present invention is applied to a liquid crystal display device in a display installed in an instrument panel of a vehicle. For example, examples of the display device include instruments such as a speedometer and a tachometer, a display device of a navigation device, and the like, and a liquid crystal display device displays a part or all of various displays performed on the display device.

  FIG. 1 is an exploded perspective view of a main part of the liquid crystal display device of the present embodiment, and FIG. 2 is a perspective view of the liquid crystal display device of the present embodiment. FIG. 3 is a cross-sectional view of the main part of the liquid crystal display device of this embodiment, and corresponds to a cross-section in the vertical direction when the main parts shown in FIG. 1 are assembled.

  As shown in FIG. 1, the liquid crystal display device includes a liquid crystal panel 1, optical sheets 2 and 3, a diffusion sheet 4, a light guide plate 5, a reflector combined case 6, a wiring board 7, an LED 8, an LED circuit 9, and a cooling module 10. Etc.

  The liquid crystal panel 1 employs a well-known TFT liquid crystal. The optical sheets 2 and 3, the diffusion sheet 4, the light guide plate 5, the reflector combined case 6, and the wiring board 7 are sequentially laminated on the back surface (rear position) of the liquid crystal panel 1, all of which are shown in FIG. 2. As shown, it is built in and held in a cover 11 constituting the outer shape of the liquid crystal display device.

  The optical sheets 2 and 3 do not reflect and transmit the light incident perpendicularly to the sheet surface from the back surface side (the right side in FIG. 3) of the sheet surface, and the sheet surface regarding the light incident from a specific direction. The light passes through the surface side of the sheet surface while being refracted in a direction perpendicular to the sheet surface. Two optical sheets called optical sheets 2 and 3 are laminated, and the two optical sheets 2 and 3 are arranged so that the specific direction is different by 90 degrees.

  The diffusion sheet 4 diffuses light incident from the back side (right side in FIG. 3) of the diffusion sheet 4 and transmits it to the front side (left side in FIG. 3). The light having no brightness is emitted toward the liquid crystal panel 1.

  The light guide plate 5 is a member constituting a transparent optical waveguide made of acrylic or the like. The light guide plate 5 guides light incident from the side edge 5a to the inside and emits it as illumination light from the surface 5b of the light guide plate. In the present embodiment, light is incident from only one of the four side edges 5a. However, in implementing the present invention, the light may be incident from other opposing surfaces.

  The reflector combined case 6 functions as a reflector having a portion constituting the reflector. The reflector combined case 6 is disposed in close contact with the back surface 5c of the light guide plate 5, and out of the light incident from the side edge 5a, light that leaks from the back surface 5c of the light guide plate 5 is guided by the light guide plate 5. It is reflected on the surface 5b side. The reflection plate in the reflection plate combined case 6 can improve the luminance of the illumination light to the liquid crystal panel 1.

  The reflector combined case 6 also functions as a case for housing the optical sheets 2 and 3, the diffusion sheet 4, and the light guide plate 5. The LED circuit 9 and the cooling module 10 are fixed to one side surface of the reflector combined case 6. FIG. 4 is an enlarged view of the cooling module 10 in FIG. 2. As shown in FIG. 1 and FIG. 1, the reflector combined case 6 using the screws 12 through the screw holes 9 a and 10 a provided in the cooling module 10. Screwed to one side.

  The wiring board 7 is provided with various circuits for driving the liquid crystal driving device, and is disposed on the back surface (rear position) of the reflector-use case 6. Specifically, the wiring board 7 includes a liquid crystal driving circuit unit used for driving the liquid crystal panel 1, an LED driving circuit unit for controlling on / off timing of energization of the LED 8 by the LED circuit 9, and the like. It has been.

  The LEDs 8 are arranged to face the side edges 5a of the light guide plate 5, and are arranged in a plurality in a direction perpendicular to the light guide plate 5 (up and down direction), and in a plurality in the direction perpendicular to the paper surface of FIG. Has been placed. The LED 8 is surface-mounted on the portion of the LED circuit 9 that faces the side edge 5 a of the light guide plate 5. The LED 8 employs a vertical light emitting diode that emits light in a direction perpendicular to the mounting surface on the wiring board 7.

  The LED circuit 9 is provided with a semiconductor switching element that performs on / off switching of energization to the LED 8. Each LED 8 is incorporated in a desired portion of the LED circuit 9 so that energization can be controlled by the semiconductor switching element of the LED circuit 9.

  The semiconductor switching element provided in the LED circuit 9 is controlled by an LED drive circuit unit provided in the wiring board 7. The LED circuit 9 is formed on an insulating film formed on, for example, a rectangular aluminum substrate, and is fixed to the reflector combined case 6 with screws 12 through screw holes 9a formed on both sides in the longitudinal direction of the aluminum substrate. The In this way, by fixing the LED circuit 9 to the reflecting plate combined case 6, each LED 8 is arranged to face the side edge 5a of the light guide plate 5 as described above.

  The cooling module 10 includes a plate 10b, a heat pipe 10c attached to the plate 10b, and a back plate 10d.

  The plate 10b is configured by the shape of the LED circuit 9, specifically, an aluminum substrate on which the LED circuit 9 is formed and a portion having a corresponding shape and a portion extending from the portion to the back plate 10d. It has a bent shape. In the plate 10b, screw holes 10a are provided on both sides in the longitudinal direction of the portion corresponding to the shape of the LED circuit 9. The plate 10b is made of aluminum, for example, and serves as a member for fixing the heat pipe 10c to the LED circuit 9.

  The heat pipe 10c functions as a heat transfer member excellent in heat transfer and having a high heat transfer rate, and is constituted by a pipe made of copper or copper alloy. In the pipe, 10% of the internal space of the pipe is used as a refrigerant. A volume of water is contained. For this reason, when the heat generated by the LED circuit 9 is transmitted to the heat pipe 10c, exhaust heat is performed using latent heat of evaporation and condensation of water stored in the heat pipe 10c. Since heat can be diffused by the heat pipe 10c without radiating much heat, the heat generated by the LED circuit 9 serving as a heat source is far from a portion of the plate 10b that is a short distance from the LED circuit 9. A large amount of heat can be transported with a small temperature difference from the distance part, that is, from the plate 10b to the back plate 10d.

  One end of the heat pipe 10c is fixed to a portion of the plate 10b that is fixed to the LED circuit 9, is bent along the plate 10b, and the other end reaches the back plate 10d and extends along the back plate 10d. It has been configured. In the case of the present embodiment, as shown in FIGS. 2 and 4, a groove is formed by denting the inner surface of the plate 10b, and the heat pipe 10c is fitted in the groove. Yes.

  The back plate 10d is disposed on the back surface (rear position) of the wiring board 7 and is configured to be in contact with the heat pipe 10c. The back plate 10d is made of, for example, a material excellent in heat transfer or a material excellent in heat dissipation, and is made of aluminum, for example. In the case of this embodiment, the back surface plate 10d and the plate 10b constitute a case that forms the outer shape of the liquid crystal display device. In this example, the plate 10b and the back plate 10d are composed of two members. However, when the plate 10b is a member excellent in heat transfer and the back plate 10d is a member excellent in heat dissipation, different materials are used. In order to be suitable, two members are used, and the member may be formed of one material.

  Next, the operation of the liquid crystal display device having the above configuration will be described.

  When the LED 8 is driven by the LED drive circuit unit provided in the LED circuit 9 and the wiring board 7, the light emitted from the LED 8 enters the side edge 5 a of the light guide plate 5 and is guided into the light guide plate 5. Thereafter, the light is emitted from the surface 5 b of the light guide plate 5 toward the diffusion sheet 4 as illumination light. At this time, the light that is about to leak out from the back surface 5 c of the light guide plate 5 is reflected to the front surface 5 b side by the reflective plate combination case 6.

  The light emitted from the surface 5b of the light guide plate 5 passes through the diffusion sheet 4, the optical sheet 3, and the liquid crystal panel 1, and is emitted from the liquid crystal panel 1 as predetermined display image light. When the liquid crystal panel 1 is driven by the display image light by the liquid crystal drive circuit unit provided on the wiring board 7, display on the liquid crystal panel 1 is performed.

  At this time, the heat generated by the LED circuit 9 is transmitted to the heat pipe 10c, and is transmitted over a wide range of the plate 10b and the back plate 10d using the heat pipe 10c as a heat transfer member. Specifically, water stored in the heat pipe 10c is evaporated by the heat transferred to the heat pipe 10c, and the steam moves upward, so that heat is transferred to a wide range of the plate 10b and the back plate 10d in a short time. It is done. Then, heat is dissipated in a wide range of the plate 10b and the back plate 10d, particularly in the back plate 10d.

  Further, when the steam is cooled by heat radiation at the plate 10b and the back plate 10d, it is condensed and returned to water, and again moves downward. And since this water is evaporated by the heat again transmitted to the heat pipe 10c, it is used for heat radiation by the same mechanism as described above. In this way, the heat generated by the LED circuit 9 is effectively dissipated.

  Next, effects obtained by the liquid crystal display device of this embodiment will be described.

  In the liquid crystal display device of the present embodiment, the heat pipe 10c is extended along a case constituted by the plate 10b and the back plate 10d arranged on the back surface of the liquid crystal display device, and the heat pipe 10c is the plate 10b and the back plate 10d. It has a structure that makes contact with a wide range. For this reason, when the heat generated by the LED circuit 9 is transmitted to the heat pipe 10c, heat can be transmitted over a wide range of the plate 10b and the back plate 10d using the heat pipe 10c as a heat transfer member. That is, heat can be efficiently transmitted to the back surface of the liquid crystal display device through the heat pipe 10c.

  For this reason, it is possible to dissipate heat over a wide range of the plate 10b and the back plate 10d, and it is possible to reduce heat transmitted to components in the vicinity of the LED circuit 9. Thereby, it can suppress that heat is transmitted to components weak to heat like the light guide plate 5 arrange | positioned in the vicinity of the LED circuit 9, the liquid crystal drive circuit part in the wiring board 7, etc. FIG. Therefore, for example, it is possible to prevent the influence of heat such that the light guide plate 5 is deformed or that the liquid crystal panel 1 cannot perform correct drawing.

  In the case of the configuration as in the present embodiment, the case including the back plate 10d can be used as a heat radiating member, so that it is possible to reduce the number of parts with respect to the parts required for heat dissipation. It becomes.

  In the present embodiment, the LED circuit 9, the plate 10 b, and the heat pipe 10 c are fixed to the reflector combined case 6 with screws 12. That is, the LED circuit 9 serving as a heat generation source and the heat pipe 10c serving as a heat transfer member can be assembled separately. Therefore, since the LED circuit 9 and the heat pipe 10c can be separated, the inspection is performed by assembling only the light guide plate 5 and the LED circuit 9, and after making various adjustments based on the inspection result, another LED circuit 9 is newly added. In the case of replacement, it is not necessary to remove the LED circuit 9 together with the heat pipe 10c, and it is possible to avoid complication of work.

(Second Embodiment)
A second embodiment of the present invention will be described. Since the basic structure of the liquid crystal display device of this embodiment is the same as that of the first embodiment, only the parts different from the first embodiment will be described here. FIG. 5 shows a cross-sectional configuration when the main part of the liquid crystal display device of this embodiment is cut in the vertical direction. FIG. 6 is an overall perspective view of the liquid crystal display device of the present embodiment. FIG. 7 is a perspective view showing only the cooling module 10 of the liquid crystal display device of the present embodiment.

  As shown in FIG. 5 to FIG. 7, in the present embodiment, the cooling module 10 includes a plate 10 b, a heat pipe 10 c, a back plate 10 d, and a configuration having radiation fins 10 e connected to the back plate 10 d. Has been.

  The heat dissipation fin 10e functions as a heat dissipation member, and has a structure in which heat dissipation efficiency is improved by integrating a plurality of fins. Each of the plurality of fins constituting the heat radiation fin 10e is formed with a through hole (not shown), and the heat pipe 10c is in contact with all of the plurality of fins through each through hole. .

  In addition, the radiation fin 10e has a plurality of fins arranged in parallel. The plurality of fins are parallel to the top-and-bottom direction so that the surrounding air heated by heat radiation can be easily removed from the uppermost position of the radiation fins 10e, that is, to facilitate air convection. Yes. And the attachment height of the radiation fin 10e is made into equivalent height with respect to another member, specifically the light-guide plate 5 and the wiring board 7 which do not want to transmit heat | fever, or a position higher than them. With such an arrangement, the heat radiation efficiency of the heat radiating fins 10 e is increased, and the heated ambient air is less likely to move in the direction of the light guide plate 5 or the wiring board 7.

  Thus, if the back surface plate 10d is provided with the heat radiating fins 10e, the heat radiation efficiency can be further increased, and the heat is less likely to be transmitted to components that do not want to transmit heat, such as the light guide plate 5 and the wiring board 7. Can be.

(Third embodiment)
A third embodiment of the present invention will be described. Since the basic structure of the liquid crystal display device of this embodiment is the same as that of the first embodiment, only the parts different from the first embodiment will be described here. FIG. 8 shows a cross-sectional configuration when the main part of the liquid crystal display device of this embodiment is cut in the vertical direction.

  As shown in this figure, in this embodiment, a light transmission plate 20 is disposed instead of the light guide plate 5 (see FIG. 3) shown in the first and second embodiments, and the light transmission plate 20 has a back surface. The LED circuit 9 is arranged, and the LED 8 is arranged on one surface of the substrate on which the LED circuit 9 is built.

  In the structure shown in the present embodiment, the light transmission plate 20 constitutes an optical waveguide, and when the light emitted from the LED 8 is transmitted through the light transmission plate 20, it is emitted toward the liquid crystal panel 1 side. Thus, display on the liquid crystal panel 1 can be performed.

  In the case of such a structure, after the heat pipe 10c is extended from the end on the back surface side of the LED circuit 9 to the end, the heat pipe 10c is further extended along the case constituted by the plate 10b and the back plate 10d. It is supposed to be.

  Also in the liquid crystal display device having such a structure, it is possible to obtain the same effect as that of the first embodiment by extending the heat pipe 10c along the case.

(Other embodiments)
In the first to third embodiments, the heat pipe 10c has been described as an example of the heat transfer member. However, any member having excellent heat transfer properties may be used, and other materials may be applied. For example, a carbon sheet affixed to a metal plate, an aluminum plate, or a conductive resin including a conductive member can be applied.

  In the second embodiment, the heat radiating fin 10e is described as an example of the heat radiating member. However, other heat radiating members may be used.

  In the above-described embodiment, the LED 8 is incorporated in the LED circuit 9 as a form in which the LED 8 is incorporated. The LED 8 is directly formed on the plate 10b on which the LED circuit 9 is patterned. In some cases, the form is separated. In this case, since the LED 8 serving as the light source is also a heat source that generates heat, the LED 8 is also mounted on the metal substrate and the heat pipe 10c is connected to the metal substrate. The heat generated by the LED 8 is released. For this reason, also regarding such a form, the effect similar to the said embodiment can be acquired by making the heat pipe 10c used as a heat-transfer member extend along a case.

It is a disassembled perspective view of the principal part of the liquid crystal display device in 1st Embodiment of this invention. 1 is an overall perspective view of a liquid crystal display device according to a first embodiment of the present invention. It is sectional drawing at the time of cut | disconnecting the principal part of the liquid crystal display device shown in FIG. It is an enlarged view of the cooling module in FIG. It is sectional drawing which cut | disconnected the principal part of the liquid crystal display device in 2nd Embodiment of this invention in the up-down direction. It is a whole perspective view of the liquid crystal display device in 2nd Embodiment of this invention. It is an enlarged view of the cooling module of the liquid crystal display device shown in FIG. It is sectional drawing which cut | disconnected the principal part of the liquid crystal display device in 3rd Embodiment of this invention in the up-down direction. It is sectional drawing which cut | disconnected the main part of the conventional liquid crystal display device in the horizontal direction.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal panel 2, 3 ... Optical sheet, 4 ... Diffusion sheet, 5 ... Light guide plate, 6 ... Reflector combined case, 7 ... Wiring board, 8 ... LED, 9 ... LED circuit, 10 ... Cooling module, 10b ... Plate, 10c ... Heat pipe, 10d ... Back plate, 10e ... Radiation fin.

Claims (7)

A liquid crystal display (1) for performing desired display with liquid crystal;
A light source (8) for illuminating the liquid crystal display (1);
An optical waveguide (5) disposed on the back side of the liquid crystal display (1) and emitting light from the light source (8) toward the liquid crystal display (1);
A wiring board (7) provided with a liquid crystal driving circuit unit for driving the liquid crystal display (1);
A drive circuit (9) that performs on-off drive of the light source (8) and serves as a heat source for generating heat;
In a liquid crystal display device comprising a heat radiating member (10d) for radiating heat generated by the drive circuit (9),
A case (10b, 10d) including a back plate (10d) disposed behind the liquid crystal display (1) and the optical waveguide (5);
A heat transfer member (10c) for transferring heat from the drive circuit (9),
Since the heat transfer member (10c) extends along the back plate (10d) and is in contact with the back plate (10d), the case (10b, 10d) is also used as a heat dissipation member. A liquid crystal display device. The liquid crystal display device according to claim 1, wherein the heat transfer member (10c) and the drive circuit (9) are configured as separate bodies. A liquid crystal display (1) for performing desired display with liquid crystal;
A light source (8) serving as a heat source for illuminating the liquid crystal display (1) and generating heat;
An optical waveguide (5) disposed on the back side of the liquid crystal display (1) and emitting light from the light source (8) toward the liquid crystal display (1);
A wiring board (7) provided with a liquid crystal driving circuit unit for driving the liquid crystal display (1);
A drive circuit (9) for performing on-off drive of the light source (8);
In a liquid crystal display device comprising a heat radiating member (10d) for radiating heat generated by the light source (8),
A case (10b, 10d) including a back plate (10d) disposed behind the liquid crystal display (1) and the optical waveguide (5);
A heat transfer member (10c) for transferring heat from the light source (8),
The case (10b, 10d) is also used as a heat radiating member by the heat transfer member (10c) extending along the back plate (10d) and in contact with the back plate (10d). A liquid crystal display device. The said back surface plate (10d) is equipped with the heat radiating member (10e) excellent in heat dissipation rather than the said heat-transfer member (10c), The one of Claim 1 thru | or 3 characterized by the above-mentioned. Liquid crystal display device. The liquid crystal display device according to claim 4, wherein the heat radiating member (10e) is disposed at a height equivalent to or higher than the optical waveguide (5) and the substrate (7). . 6. The heat transfer member (10c) according to any one of claims 1 to 5, wherein at least one of a heat pipe, a metal plate, a member including a carbon sheet, a conductive member, and the like is used. Liquid crystal display device. The heat radiating member (10e) includes a plurality of fins stacked in parallel, and the plurality of fins are arranged parallel to the top-to-bottom direction. The liquid crystal display device according to one.

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