JP2014149386A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device which can prevent a light-emitting device from overheating and can prevent adverse influences of heat generation by the light-emitting device on a light guide plate or an optical sheet.SOLUTION: The liquid crystal display device is provided with a heat diffusing member 10 which includes a heat absorbing part 10a in contact with or close to a light-emitting device 7 and a heat radiation part 10b disposed outside a back cover 5 so as to absorb the heat of the light-emitting device 7 by the heat absorbing part 10a and to diffuse the heat to the outside by the heat radiation part 10b. A fourth space S4 is formed between the heat radiation part 10b and the back cover 5, a third space S3 is formed between the back cover 5 and a light guide plate 6, and thereby, heat is not transmitted to the light guide plate 6. A second space S2 is formed between the light guide plate 6 and an optical sheet 2, a first space S1 is formed between the optical sheet 2 and a liquid crystal display panel 1, and thereby, heat is less likely transmitted to the optical sheet 2 and the liquid crystal display panel 1. The light guide plate 6 and the back cover 5 are clamped by a pressing part 8b and the heat radiation part 10b, which increases the fixture strength of the light guide plate 6.

Description

  The present invention relates to a liquid crystal display device capable of suppressing adverse effects due to heat generation of a light emitting device constituting a backlight device.

  In general, a liquid crystal display device irradiates light from the back side of a liquid crystal display panel in which liquid crystal is sealed through an alignment film between two transparent substrates including a transparent electrode and a color filter. A backlight device, applying a voltage to the transparent electrode to displace the molecular arrangement of the liquid crystal, and changing the transmittance of light emitted from the backlight device, so that the target image is displayed on the liquid crystal display panel. It is displayed on the display surface.

  Due to the structure of the backlight device, the liquid crystal display device has a direct type in which a light emitting device serving as a light source is disposed on the back side of the liquid crystal display panel, and a light emitting device on the edge side of the light guide disposed on the back surface of the liquid crystal display panel. It is roughly classified into the edge light type to be arranged. The edge light type liquid crystal display device has an advantage that the thickness can be reduced as compared with the direct type, and recently, the liquid crystal display device employing the edge light type backlight device is becoming mainstream. Moreover, although there exist a cathode tube and LED (Light Emitting Diode) about the light-emitting device used as a light source, there exists a tendency for LED with small power consumption to be utilized.

  By the way, in order to increase the luminance of the display surface of the liquid crystal display panel, the light emitting device needs to emit light with high luminance. However, in the edge light type backlight device, the light emitting device is concentrated on the edge side of the light guide plate. When the light is emitted with high brightness, the light emitting device may become high temperature. Therefore, when an LED is used for the light emitting device, the LED is not high in heat resistance, so that there is a problem of damage due to heat during high luminance light emission. Therefore, in the high-brightness type liquid crystal display device, a direct-type backlight device has to be employed, and there is a problem that it is difficult to reduce the thickness.

  In order to apply an edge-light type backlight device to a high-brightness type liquid crystal display device, overheating prevention means of the light-emitting device is required. Patent Document 1 describes a technique for preventing overheating in a light emitting device of an edge light type backlight device. Patent Document 1 describes a structure in which a plurality of LEDs that are light emitting devices are classified into two or more groups, and each group is mounted on a different constituent member. Specifically, each of the plurality of LEDs disposed on the side of the light guide plate is alternately mounted on the front cover and the rear cover. According to Patent Document 1, such a configuration can increase the heat dissipating area per LED and increase the heat dissipating efficiency, so that a heat dissipating member such as a heat sink can be omitted, and the liquid crystal display device can be made thinner and lighter. It is supposed to be able to plan.

  FIG. 4 is a cross-sectional view showing a schematic configuration of a main part of a conventional liquid crystal display device M, and shows a conventional example in which an overheating prevention technique for the light emitting device 27 of the edge light type backlight device 23 is different. In the figure, the surface corresponding to the display surface side of the liquid crystal display device M is referred to as “front surface”, and the opposite surface opposite to this is referred to as “back surface”.

  A liquid crystal display device M illustrated in FIG. 4 includes a liquid crystal display panel 21, an optical sheet 22 such as a polarizing sheet disposed on the back side of the liquid crystal display panel 21, and an edge light disposed on the back side of the optical sheet 22. Type backlight device 23, a heat absorbing member 30 disposed on the back side of the backlight device 23, a back cover 25 that covers the back surface of the heat absorbing member 30, and a support portion that supports the rear surface of the edge of the liquid crystal display panel 21. A frame member 28 having 28 a and a surface cover 29 having an inner edge portion 29 a that presses the front surface of the edge portion of the liquid crystal display panel 21 are provided.

  The backlight device 23 includes a light guide plate 26 and a light emitting device 27 disposed in the vicinity of the edge of the light guide plate 26, and a reflection sheet 24 is provided on the back surface of the light guide plate 26. The light emitting device 27 includes a light emitting element 27a made of an LED and a control board 27b. Further, although not shown in the figure, a control unit is provided for processing the video data and performing voltage control of the liquid crystal display panel 21 and luminance control of the backlight device 23.

  In the conventional example of FIG. 4, a heat absorbing member 30 is disposed between the light guide plate 26 and the back cover 25 with one end 30 a being in contact with or close to the control board 27 b of the light emitting device 27. The heat absorbing member 30 absorbs and diffuses the heat generated in the light emitting device 27 to prevent overheating of the light emitting device 27. The heat absorbing member 30 is formed with large and small raised portions 31 and 32, and the raised portions 31 and 32 are brought into contact with the reflection sheet 24 provided on the back surface of the light guide plate 26 to support the light guide plate 26. It is said.

JP 2009-037212 A

  The present inventors have obtained knowledge that a liquid crystal display device having an edge light type backlight device may cause the following problems in addition to the problem that the light emitting device is damaged by overheating. It was. First, in the light guide plate, the light emitted from the light emitting device is not normally incident on the light guide plate as a result of being heated by the heat generated by the light emitting device and causing deformation such as elongation and warpage due to thermal expansion. There is a problem that efficiency is lowered and light leakage occurs. Next, in the optical sheet, the temperature rises only in the vicinity of the light emitting device that has reached a high temperature, and as a result of local expansion, wrinkles are generated in the optical sheet, and the transmitted light becomes non-uniform, resulting in display. There is a problem that the image is uneven. Furthermore, in the liquid crystal display panel, when the heat of the light-emitting device is transmitted and the temperature of the liquid crystal display panel rises, the characteristics of the liquid crystal display panel change and the luminance of the black image increases, resulting in unevenness in the display image. Or the contrast ratio is relatively lowered, and there is a problem that the display quality of the video deteriorates.

  Patent Document 1 does not consider the above-described problems other than the damage of the light emitting device. That is, the above-mentioned problem cannot be solved. In addition, since the conventional liquid crystal display device described in Patent Document 1 employs a complicated structure in which LEDs classified into two or more groups are mounted on different components, it is difficult to manufacture the liquid crystal display device. There is a problem that increases the cost of the display device.

  Since the conventional liquid crystal display device M shown in FIG. 4 does not take measures against the above-described problems other than prevention of overheating of the light emitting device 27, the following problems are caused. The heat absorbing member 30 has a configuration in which one end portion 30 a is in contact with or close to the light emitting element 27 a and the raised portions 31 and 32 are in contact with the reflection sheet 24. For this reason, the heat of the light emitting device 27 that has absorbed heat at the one end 30 a is diffused throughout the heat absorbing member 30, and the heat is transmitted to the light guide plate 26 through the reflection sheet 24 through the raised portions 31 and 32. . As a result, the light guide plate 26 is deformed to extend or warp due to thermal expansion, so that the positional relationship between the light emitting surface of the light emitting device 27 and the light incident surface of the light guide plate 26 is displaced, and light is incident. There is a problem that the efficiency is lowered and the designed luminance cannot be obtained.

  In addition, since the reflective sheet 24 is locally heated to cause partial thermal expansion, wrinkles are generated in the reflective sheet 24 and the light reflection state becomes uneven. Further, the heat of the light emitting device 27 is also transmitted to the optical sheet 22 through the light guide plate 26, and the optical sheet 22 is locally heated and partially thermally expanded. As a result, the optical sheet 22 is wrinkled. There is a problem that the light transmission state becomes non-uniform.

  Furthermore, since the heat absorbing member 30 is housed inside the back cover 25, the heat of the heat absorbing member 30 is unlikely to be dissipated outside. That is, the heat generated by the light emitting device 27 is likely to be accumulated inside the back cover 25. Therefore, the overheat prevention function by the heat absorbing member 30 is not sufficiently exhibited, and the temperature of the light emitting device 27, the light guide plate 26, the optical sheet 22, and the liquid crystal display panel 21 rises, and the above-described problems are likely to occur.

  An object of the present invention is to provide a liquid crystal display device which can prevent overheating of a light emitting device with a simple configuration and can prevent the heat generated by the light emitting device from adversely affecting the light guide plate and the optical sheet. .

  The present invention relates to a liquid crystal display panel, a light guide plate disposed on the back side of the liquid crystal display panel, a light emitting device disposed in proximity to a side surface of the light guide plate, and a back surface covering the back surface of the light guide plate A cover, a heat absorbing part disposed in contact with or in proximity to the light emitting device, and absorbing heat generated from the light emitting device; and a heat absorption unit provided integrally with the heat absorbing unit and disposed outside the back cover. And a heat dissipating member having a heat dissipating part for dissipating the liquid to the outside.

  Further, the present invention is characterized in that the heat dissipating member and at least a part of the back cover facing the heat dissipating member are spaced apart.

  In the invention, it is preferable that the back cover and the light guide plate are spaced apart from each other.

  The present invention further includes a frame member having a pressing portion that presses the front surface of the edge portion of the light guide plate, and the light guide plate and the back cover are formed by the pressing portion and the heat dissipation portion of the heat dissipating member. It is characterized by being pinched.

  Further, according to the present invention, the frame member and the heat dissipating member have a contact portion in contact with each other, and a convex portion is formed on one of the frame member and the heat dissipating member at the contact portion. A concave portion for fitting the convex portion is formed.

  According to the present invention, the heat dissipating member provided in the liquid crystal display device is disposed in contact with or in close proximity to the light emitting device, the heat absorbing portion integrally provided in the heat absorbing portion, and disposed outside the back cover. Therefore, the heat absorbing portion absorbs heat generated from the light emitting device, and the heat radiating portion dissipates the heat to the outside. Since the heat radiating portion is disposed outside the back cover, it can directly contact the outside air and efficiently dissipate the absorbed heat to the outside. Therefore, it exhibits an excellent overheating preventing effect on the light emitting device. In addition, since the heat radiating part is arranged outside the back cover and the back cover is interposed between the light guide plate and the heat radiating part, the heat dissipated in the heat radiating part is directly transmitted to the light guide plate. There is no. Therefore, the light guide plate can be prevented from being heated and deformed. Further, since the heating of the light guide plate is prevented, the heating of the optical sheet and the liquid crystal display panel is also prevented, so that the conventional problems can be solved.

  According to the present invention, since the heat dissipating member and at least a part of the portion of the back cover that faces the heat dissipating member are arranged apart from each other, the heat dissipated from the heat dissipating member is transmitted to the back cover. It becomes difficult. Therefore, the effect of preventing the light guide plate from being heated via the back cover can be further enhanced.

  According to the present invention, since the back cover and the light guide plate are spaced apart from each other, even if the heat dissipated from the heat dissipating member is transmitted to the back cover, the heat is not easily transmitted from the back cover to the light guide plate. Become. Therefore, the effect of preventing the light guide plate from being heated can be further enhanced.

  Further, according to the present invention, the frame member is provided with the pressing member that presses the front surface of the edge portion of the light guide plate. Therefore, the light from the end surface of the light guide plate is covered with the pressing member by covering the edge portion of the light guide plate. It becomes possible to prevent leakage. Moreover, since it was set as the structure which clamps a light guide plate and a back cover with the holding | suppressing part of a frame member, and the thermal radiation part of a heat-dissipating member, the fixed intensity | strength of a light guide plate can be improved.

  Further, according to the present invention, the contact portion between the frame member and the heat dissipating member has a structure in which a convex portion is formed on one side and a concave portion is formed on the other, and the both are fitted to each other. The structure that sandwiches the light guide plate and the back cover with the heat radiating portion of the member can be made more rigid.

It is sectional drawing which shows schematic structure of the principal part of liquid crystal display device L1 which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows schematic structure of the principal part of liquid crystal display device L2 which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows schematic structure of the principal part of liquid crystal display device L3 which concerns on the 3rd Embodiment of this invention. It is sectional drawing which shows schematic structure of the principal part of the conventional liquid crystal display device.

(First embodiment)
FIG. 1 is a cross-sectional view showing a schematic configuration of a main part of a liquid crystal display device L1 according to the first embodiment of the present invention. In the following description, the surface corresponding to the display surface side of the liquid crystal display panel 1 is referred to as “front surface”, the opposite surface facing this is referred to as “back surface”, and the surface perpendicular to the front surface and the back surface is referred to as “front surface”. “Side”.

  The liquid crystal display device L1 of the present embodiment includes a liquid crystal display panel 1, an optical sheet 2 such as a polarizing sheet disposed on the back side of the liquid crystal display panel 1, and an edge light type disposed on the back side of the optical sheet 2. A backlight device 3, a back cover 5 that covers the back side of the light guide plate 6 that constitutes the backlight device 3, a heat dissipating member 10 that is disposed in contact with or close to the light emitting device 7 that constitutes the backlight device 3, A frame member 8 having a support portion 8a that supports the rear surface of the edge portion of the liquid crystal display panel 1 and a pressing portion 8b that presses the front surface of the edge portion of the light guide plate 6, and an inner edge portion 9a that covers the front surface of the edge portion of the liquid crystal display panel 1. And a surface cover 9 having Further, although not shown in the figure, a control unit that performs electrical control such as voltage control of the liquid crystal display panel 1 and luminance control of the backlight device 3 is provided.

  In the present embodiment, the edge of the liquid crystal display panel 1 is sandwiched between the inner edge 9 a of the surface cover 9 and the support 8 a of the frame member 8 via the packing 13. Further, the edge portion of the optical sheet 2 is inserted into a gap formed between the support portion 8a and the pressing portion 8b provided in the frame member 8 so as to compress the packing 14, and thereby the optical sheet 2 is compressed. Is supported. Note that the support portion 8 a and the pressing portion 8 b of the frame member 8 are formed by a bifurcated portion that protrudes from the main portion 8 d of the frame member 8 and branches.

  The backlight device 3 is an edge light type having a light guide plate 6 and a light emitting device 7 disposed in the vicinity of an edge portion of the light guide plate 6. On the back surface of the light guide plate 6, a reflection sheet 4 that reflects incident light toward the liquid crystal display panel 1 is provided. In the present embodiment, the light-emitting device 7 includes a light-emitting element 7a composed of LEDs arranged close to the edge of the light guide plate 6, and a control board 7b on which the light-emitting element 7a is mounted. Note that a plurality of light emitting devices 7 may be provided along the edge of the light guide plate 6, or a plurality of light emitting elements 7a may be mounted on a single control board 7b as a unit. .

  A spacer 11 is arranged between the back surface of the light guide plate 6 provided with the reflection sheet 4 and the back cover 5, and the back cover 5 and the light guide plate 6 are separated by the spacer 11. The spacer 11 may be formed of an elastic body having heat insulation properties.

  The back cover 5 is provided with a protruding portion 12 on the back surface, and the protruding portion 12 contacts the heat radiating portion 10 b of the heat dissipating member 10. The protrusion 12 may be formed integrally with the back cover 5 or may be attached separately.

  As shown in FIG. 1, the heat dissipating member 10 of the present embodiment is a plate-like member having a substantially L-shaped cross section, and one of the vertically combined plate-like bodies is the light emitting device 7. The heat absorption part 10a that is in contact with or close to the control board 7b is configured, and the other plate-like body integrally provided so as to be substantially perpendicular to the heat absorption part 10a is exposed to the outside of the back cover 5. Constitutes the heat dissipating part 10b. In addition, it is also possible to make the heat-dissipating member 10 by assembling the heat-absorbing part 10a and the heat-dissipating part 10b separately manufactured. The heat radiating portion 10 b is separated from the back cover 5 except for the contact portion with the protruding portion 12 by contacting the protruding portion 12. The heat dissipating member 10 is made of a material having excellent heat conductivity, and for example, copper, copper alloy, aluminum, aluminum alloy or the like is used.

  The heat dissipating member 10 is designed such that the volume per light emitting device 7 has a heat capacity that can reliably absorb the heat of the light emitting device 7, and the surface area on the back side of the heat radiating portion 10b is reduced to the outside air. It is designed so that the heat dissipation function can be fully demonstrated.

  The frame member 8 is provided so as to cover the front surface and the side surface of the heat dissipating member 10. The front cover 9 is provided so as to cover the front surface and side surfaces of the frame member 8 together with the front surface of the edge portion of the liquid crystal display panel 1.

  The frame member 8 and the heat dissipating member 10 have contact portions T that are in contact with each other. In the present embodiment, the vicinity of the base of the bifurcated protruding portion that forms the support portion 8 a and the pressing portion 8 b in the frame member 8 and the front end surface of the heat absorbing portion 10 a in the heat dissipating member 10 are brought into contact with each other. Further, a protrusion 8c such as a ridge is formed in the vicinity of the base portion of the frame member 8, a recess 10c such as a groove is formed on the front end surface of the heat dissipating member 10, and the protrusion 8c and the recess 10c are fitted. It has a structure. Thereby, when the light guide plate 6 and the back cover 5 are sandwiched between the pressing portion 8b of the frame member 8 and the heat radiating portion 10b of the heat dissipating member 10, a firm clamping state can be obtained. In addition, the uneven structure provided in the contact portion T between the frame member 8 and the heat dissipating member 10 can have the frame member 8 side as a concave portion and the heat dissipating member 10 side as a convex portion.

  The frame member 8 holds the light guide plate 6 firmly and maintains the positional relationship with the liquid crystal display panel 1 so that the light incident efficiency from the light emitting device 7 to the light guide plate 6 is not lowered. It is required to have rigidity and strength. Further, although it is in contact with the heat dissipating member 10, since it supports the liquid crystal display panel 1, the optical sheet 2, and the light guide plate 6, the heat absorbed by the heat dissipating member 10 is the liquid crystal display panel 1, the optical sheet 2, and In order to prevent the light from being transmitted to the light guide plate 6, it is desirable to have excellent heat insulation as much as possible. Therefore, for the frame member 8, as a material satisfying such conditions, for example, PC (polycarbonate) resin, ABS (acrylonitrile-butadiene-styrene) resin, or glass fiber reinforced resin obtained by adding glass fiber to these resins. Etc. are used.

The liquid crystal display device L1 configured as described above includes the liquid crystal display panel 1 sandwiched between the inner edge portion 9a of the front cover 9 and the support portion 8a of the frame member 8, and the support portion 8a and the pressing portion 8b of the frame member 8. A first space S1 having a thickness corresponding to the support portion 8a is formed between the optical sheet 2 supported therebetween. A second space S2 having a thickness corresponding to the pressing portion 8b is formed between the optical sheet 2 and the light guide plate 6 pressed by the pressing portion 8b. A third space S3 having a thickness corresponding to the spacer 11 is formed between the light guide plate 6 including the reflective sheet 4 and the back cover 5. A fourth space S <b> 4 having a thickness corresponding to the protruding portion 12 is formed between the back cover 5 and the heat radiating portion 10 b of the heat dissipating member 10.
The third space S3 and the fourth space S4 can be filled with a heat insulating material.

  The liquid crystal display device L1 according to the present embodiment exhibits the following operations and effects. When the light emitting device 7 generates heat as the liquid crystal display device L1 is driven, the heat absorbing portion 10a of the heat dissipating member 10 absorbs the heat of the light emitting device 7 and transmits this heat to the heat radiating portion 10b. Since the heat radiating part 10b is disposed so as to be exposed to the outside of the back cover 5, it can directly contact the outside air and efficiently dissipate the absorbed heat to the outside. Therefore, an excellent overheating preventing effect is exhibited for the light emitting device 7.

  A fourth space S4 is formed between the heat radiating portion 10b and the back cover 5, and since the heat radiating portion 10b is only in contact with the protruding portion 12, the contact area is small. Therefore, the heat of the heat radiating part 10 b is not easily transmitted to the back cover 5. Further, a third space S3 is formed between the back cover 5 and the light guide plate 6, and the back cover 5 and the light guide plate 6 are in contact with the spacer 11, respectively, but the contact area is small. Therefore, even if the heat of the heat radiating part 10 b is transmitted to the back cover 5, this heat is not easily transmitted to the light guide plate 6. Therefore, the light guide plate 6 and the reflection sheet 4 can be prevented from being heated and deformed.

  Further, a second space S <b> 2 is formed between the light guide plate 6 and the optical sheet 2, and a first space S <b> 1 is formed between the optical sheet 2 and the liquid crystal display panel 1. That is, the optical sheet 2 and the liquid crystal display panel 1 have a structure in which the heat of the heat radiating portion 10b is more difficult to be transmitted. Therefore, by preventing the light guide plate 6 from being heated, the heating of the optical sheet 2 and the liquid crystal display panel 1 can also be reliably prevented.

  Since the front surface of the edge portion of the light guide plate 6 is covered with the pressing portion 8b of the frame member 8, the light emitted from the end surface of the light guide plate 6 or the light emitted from the light emitting device 7 is reflected on the liquid crystal display panel 1. Leakage to the front side can be prevented.

  Since the light guide plate 6 is sandwiched between the pressing portion 8b of the frame member 8 and the heat radiating portion 10b of the heat dissipating member 10 together with the back cover 5, the fixing strength of the light guide plate 6 can be improved.

  In addition, in the present embodiment, since the convex portion 8c provided on the frame member 8 and the concave portion 10c of the heat dissipating member 10 are fitted, the coupling strength between the frame member 8 and the heat dissipating member 10 can be increased. . As a result, the structure for sandwiching the light guide plate 6 and the back cover 5 can be made more rigid.

  As described above, since the liquid crystal display device L1 according to the present embodiment can solve all of the conventional problems described above, an edge-light type backlight device is employed to achieve a high-luminance type that is thin. A liquid crystal display device can be provided. In addition, since the problem that the light emitting device 7 is damaged due to overheating and the heat generated by the light emitting device 7 adversely affects the light guide plate 6, the optical sheet 2, and the liquid crystal display panel 1, the display quality can be stabilized. it can.

(Second Embodiment)
FIG. 2 is a cross-sectional view showing a schematic configuration of a main part of a liquid crystal display device L2 according to the second embodiment of the present invention. In the liquid crystal display device L2 according to this embodiment, the description of the configuration common to the liquid crystal display device L1 according to the first embodiment is omitted.

  The liquid crystal display device L2 according to this embodiment is different from the first embodiment in the following two points. The first point is that the light guide plate 6 including the reflection sheet 4 and the back cover 5 are brought close to or in close contact with each other, thereby eliminating the third space S3. The second point is that a plurality of grooves 15 are formed on the back surface of the heat dissipating part 10 b of the heat dissipating member 10.

  When the heat generation amount of the light emitting device 7 is small and the heat dissipating performance of the heat dissipating member 10 is high, only the fourth space S4 between the back cover 5 and the heat dissipating part 10b can be used to connect the heat dissipating part 10b to the light guide plate 6. It is thought that heat conduction can be prevented. Therefore, in such a case, as shown in FIG. 2, the third space S3 is omitted, and the reflective sheet 4 of the light guide plate 6 and the back cover 5 are brought close to or in close contact with each other, whereby the thickness dimension of the liquid crystal display device L2 is obtained. This makes it possible to provide a thinner product.

  Moreover, in this embodiment, in order to improve the heat dissipation performance of the heat dissipating member 10, a large number of grooves 15 are formed in the heat dissipation portion 10b. That is, the groove 15 is formed to have a concavo-convex shape, thereby increasing the surface area of the heat radiating portion 10b and improving the heat radiating performance.

  What is necessary is just to determine suitably the cross-sectional shape of the groove | channel 15, a width dimension, a formation direction, a formation space | interval, the number of formation etc. according to the implementation condition. In the embodiment of FIG. 2, the groove 15 has a rectangular cross section, but the cross section may be triangular or pentagonal. Further, the depth of the groove 15 may not be constant. For example, the groove 15 at a position close to the heat absorbing portion 10 a may be deepened so as to approach the light emitting device 7. In FIG. 2, the groove 15 is formed in parallel with the direction in which the light emitting device 7 is disposed. However, the groove 15 may be formed in a direction perpendicular to the direction, or inclined with respect to the direction in which the light emitting device 7 is disposed. You may form the groove | channel 15 in the direction to do. Furthermore, it is possible to form grooves 15 having different formation directions on the surface of the heat radiating portion 10b so as to intersect each other.

  By forming the groove 15 in the heat radiating portion 10b, the surface area per unit length of the heat radiating portion 10b is increased. Therefore, the length of the heat radiating portion 19b for obtaining a necessary heat radiating area can be shortened. Furthermore, the formation of the groove 15 can reduce the weight.

(Third embodiment)
FIG. 3 is a cross-sectional view showing a schematic configuration of a main part of a liquid crystal display device L3 according to the third embodiment of the present invention. In the liquid crystal display device L3 according to the present embodiment, the description of the configuration common to the liquid crystal display device L1 according to the first embodiment is omitted.

  The liquid crystal display device L3 according to this embodiment is different from the first embodiment in the following two points. 1st is the point which made the thermal radiation part 10b of the heat-dissipating member 10 and the back cover 5 adjoin or contact | close, and eliminated 4th space S4. The second point is that a plurality of through holes 16 are formed in the heat dissipating part 10 b of the heat dissipating member 10.

  When the heat generation amount of the light emitting device 7 is small and the heat dissipation performance of the heat dissipating member 10 is high, only the third space S3 between the light guide plate 6 including the reflective sheet 4 and the back cover 5 can be removed from the heat radiating unit 10b. It is considered that heat conduction to the light guide plate 6 can be prevented. Therefore, in such a case, as shown in FIG. 3, the thickness of the liquid crystal display device L3 is reduced by omitting the fourth space S4 and bringing the heat radiating portion 10b of the heat dissipating member 10 and the back cover 5 close to each other. It is possible to provide a thinner product by reducing the size.

  In the present embodiment, a large number of through holes 16 are formed in the heat radiating portion 10b to increase the surface area of the heat radiating portion 10b and reduce the contact area between the heat radiating portion 10b and the back cover 5. The expansion of the surface area can improve the heat dissipation performance, and the reduction of the contact area makes it difficult for heat to be transferred from the heat dissipation portion 10b to the back cover 5.

  What is necessary is just to determine suitably the hole diameter of the through-hole 16, a formation space | interval, the number of formation, etc. according to the implementation condition. By forming the through hole 16, the surface area per unit length of the heat radiating portion 10b is increased, and therefore the length of the heat radiating portion 10b for obtaining a required surface area can be shortened. Further, the formation of the through hole 16 can reduce the weight.

(Other embodiments)
In the first to third embodiments described above, at least one of the third space S3 between the light guide plate 6 and the back cover 5 and the fourth space S4 between the back cover 5 and the heat radiating portion 10b. However, if the heat dissipating member 10 has a necessary and sufficient heat dissipation performance with respect to the heat generation amount of the light emitting device 7, both the third space S3 and the fourth space S4 are omitted. It is possible. That is, a thinner liquid crystal display device can be provided as a configuration in which the back cover 5 is brought close to or in close contact with the reflective sheet 4 of the light guide plate 6 and the heat radiating portion 10 b is brought close to or in close contact with the back cover 5.

  The uneven structure formed at the contact portion T between the frame member 8 and the heat dissipating member 10 is not essential and may be omitted. In addition, the specific configuration of the present invention can be changed as appropriate according to the situation of implementation.

L1 Liquid crystal display device L2 Liquid crystal display device L3 Liquid crystal display device 1 Liquid crystal display panel 2 Optical sheet 3 Backlight device 4 Reflective sheet 5 Back cover 6 Light guide plate 7 Light emitting device 7a Light emitting element 7b Control board 8 Frame member 8a Supporting portion 8b Holding portion 8c Convex portion 8d Main portion 9 Surface cover 9a Inner edge portion 10 Heat dissipating member 10a Heat absorbing portion 10b Heat radiating portion 10c Recessed portion 11 Spacer 12 Protruding portion 13 Packing 14 Packing 15 Groove 16 Through hole S1 First space S2 Second space S3 Second 3 space S4 4th space T contact part

Claims (5)

A liquid crystal display panel, a light guide plate disposed on the back side of the liquid crystal display panel,
A light emitting device disposed close to the side surface of the light guide plate;
A back cover covering the back of the light guide plate;
A heat absorbing part that is disposed in contact with or close to the light emitting device and absorbs heat generated from the light emitting device, and is provided integrally with the heat absorbing unit, and is disposed outside the back cover to dissipate heat to the outside. A liquid crystal display device comprising: a heat dissipating member having a heat dissipating part that diverges.   2. The liquid crystal display device according to claim 1, wherein the heat dissipating member and at least a part of a portion of the back cover facing the heat dissipating member are arranged apart from each other.   The liquid crystal display device according to claim 1, wherein the back cover and the light guide plate are spaced apart from each other. A frame member having a pressing portion for pressing the front surface of the edge portion of the light guide plate,
The liquid crystal display device according to claim 1, wherein the light guide plate and the back cover are sandwiched between the pressing portion and the heat radiating portion of the heat dissipating member. The frame member and the heat dissipating member have contact portions in contact with each other,
5. The contact portion according to claim 4, wherein a convex portion is formed on one of the frame member and the heat dissipating member, and a concave portion for fitting the convex portion is formed on the other. Liquid crystal display device.

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