JP6101518B2 - Display device - Google Patents

Description

The present invention relates to a display device including a light emitting device that constitutes a backlight device of a display panel used in a liquid crystal display device.

  The backlight device that irradiates light from the back side of a display panel of a liquid crystal display device such as a liquid crystal television or a liquid crystal display includes a direct type in which a light emitting device as a light source is disposed on the entire back side of the display panel, and a back surface of the display panel There is an edge light type in which a light emitting device is arranged on the edge side of a light guide plate arranged in the above. 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. As for the light emitting device used as a light source, although there is a cold cathode tube, an LED (Light Emitting Diode) with low power consumption tends to be used.

  Incidentally, in order to increase the luminance of the display surface of the display panel, it is necessary to cause the light emitting device 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. Therefore, when the light is emitted with high luminance, the light emitting device may become high temperature. Therefore, when an LED is used in the light emitting device, the heat resistance of the LED is not high. Therefore, when the light is emitted at a high brightness, the brightness becomes uneven due to a decrease in light output, the service life is shortened, and the light is damaged. May cause problems. In particular, the outdoor-installed liquid crystal display device may require 5 to 10 times the brightness of the indoor-installed liquid crystal display device. Since the light emitting device emits light with high brightness by increasing the current value of electricity to be energized, the above-mentioned problems are likely to occur. Therefore, conventionally, as a means for preventing overheating of a light emitting device of an edge light type backlight device applied to a liquid crystal display device, for example, a cooling device as described in Patent Document 1 has been proposed.

  FIG. 11 shows a cooling device 1 for preventing overheating of the light emitting device 5 of the display device D described in Patent Document 1. As shown in FIG. The light emitting device 5 including the LED 3 and the substrate 4 is disposed close to the lower side end face of the display panel 2. The cooling device 1 includes a hollow box-shaped heat sink 6 provided in contact with a surface opposite to the LED mounting surface on which the LEDs 3 of the substrate 4 are mounted, and a plurality of fans 7 attached to the heat sink 6. .

  The heat sink 6 is made of a metal such as aluminum or copper, and has an opening in the back surface portion 6b facing the side opposite to the display surface of the display panel 2 out of the surfaces perpendicular to the substrate mounting surface 6a in contact with the substrate 4. doing. That is, an air inflow port 9 is formed in the center of the back surface portion 6b, and air discharge ports are formed on both left and right sides of the back surface portion 6b. Exhaust air that sucks air out of the heat sink 6 into each of the left and right discharge ports. A fan 7 is attached. The end face 6c in the longitudinal direction of the heat sink 6 is closed by a wind leak prevention cover. A plurality of fins 8 formed in parallel to the substrate mounting surface 6a are provided inside the heat sink 6.

  Based on such a configuration, the cooling device 1 of Patent Document 1 absorbs heat generated from the substrate 4 of the light emitting device 5 by the heat sink 6 in contact therewith. When the fan 7 is operated, air flows from the inlet 9 provided in the center of the heat sink 6 in the direction of the arrow Y1, branches in the two directions indicated by the arrow Y2, and flows in the heat sink 6. Then, after absorbing heat from the heat sink 6, it is discharged to the outside in the direction of arrow Y3 from the two outlets at both ends. As a result, the LED 3 in the central region where the temperature tends to be high can be cooled with fresh and low temperature air, and the air flows uniformly to the left and right. The display device D can be provided with little luminance unevenness even when high-luminance emission is performed.

JP 2007-101766 A

  In the cooling device 1 described in Patent Document 1, both end surfaces in the longitudinal direction of the heat sink 6 are closed, and the arrow Y1 direction in which air is sucked into the heat sink 6, the arrow Y2 direction in which air flows in the heat sink 6, The directions of the arrows Y3 through which air is discharged from the heat sink 6 are different from each other. That is, the air flow path is not linear. For this reason, since air receives resistance from the inner wall surface of the heat sink 6 when air flows through a non-linear path, the flow of air is poor. That is, since the cooling device 1 of Patent Document 1 has a structure that reduces the exhaust capability of the fan 7, it is necessary to increase the output of the fan 7 in order for the heat sink 6 to have a sufficient cooling effect, and the energy is increased accordingly. There is a problem that the consumption increases and the operating cost of the display device D and the like increases.

  Moreover, since the heat sink 6 of patent document 1 has a structure which does not have an opening part other than the air inflow port 9 and an exhaust port, there exists a problem that an internal cleaning is difficult.

An object of the present invention is to provide a display device that can solve the conventional problems.

Display invention, which includes a display panel, and projecting light to the side end surface of the back side light guide plate disposed on the display panel, and a light emitting device for irradiating light to the display panel from the back side A device ,
The light emitting device
A substrate disposed in the vicinity of the side end surface of the light guide plate and having a direction along the longitudinal direction of the side end surface as a longitudinal direction;
A light source provided on one side of the substrate facing the light guide plate;
A cooling member provided in contact with the other surface opposite to the one surface of the substrate and extending in the longitudinal direction of the substrate ;
An endothermic part that contacts the other surface and absorbs heat of the substrate;
A heat dissipating part that is provided integrally with the heat absorbing part and dissipates the heat absorbed by the heat absorbing part to the outside, and passes through the air passage in the direction along the longitudinal direction of the substrate, and at both ends of the air passage is formed to have a vent port opening to the through direction of the vent passage is the display device characterized by comprising a cooling member having a cylindrical heat radiation member for supporting the back side of the display panel .

  Further, the invention is characterized in that the substrate is disposed close to a side end surface along a vertical direction of the light guide plate in a state where the display device stands the display panel and the light guide plate.

  Moreover, the present invention is characterized in that the heat radiating portion has a plurality of air passages whose penetration directions are parallel to each other.

  Further, the present invention is characterized in that the heat radiating portion further has a plate-like heat radiating fin having a longitudinal direction in a through direction of the air passage on an inner surface of the air passage.

  In the invention, it is preferable that the heat dissipating part further includes a second heat dissipating fin on the outer surface.

  Further, the present invention is characterized in that a back cover portion that covers a back surface of the light guide plate is integrally formed with the heat radiating portion.

  Further, the present invention is characterized in that a pressing portion for pressing the front surface of the edge portion of the display panel is integrally formed with the heat absorbing portion.

  According to the present invention, the cooling member of the light emitting device disposed in the vicinity of the side end surface of the light guide plate includes a heat absorption part that contacts the substrate, and a heat dissipation part that is provided integrally with the heat absorption part and has a ventilation path. The heat absorbing part absorbs heat generated from the substrate, and this heat is transmitted to the heat radiating part, and the heat radiating part transmits this heat to the air in the air passage. And the air in a ventilation path is made to flow using a fan etc., and the heat | fever is discharged | emitted by releasing the heated air continuously. As described above, the heat absorption unit absorbs heat from the substrate and dissipates this heat from the heat dissipation unit to the outside, so that overheating of the light emitting device can be prevented.

  In the present invention, the penetration direction of the air passage is a direction along the longitudinal direction of the substrate, and the vents are opened at both ends of the air passage. Therefore, resistance when air flows in the air passage is small. . In addition, since there are no electronic devices or circuits inside the air passage, a filter that covers the air vent is unnecessary. As described above, since the air passage of the present invention does not have an element that provides airflow resistance, when air is flowed by a fan or the like, the air flow in the air passage is good and the fan output is small. However, it effectively dissipates heat from the heat radiating part to the outside and exhibits an excellent cooling effect. Therefore, energy consumption is suppressed, and the operating cost of the liquid crystal display device can be reduced.

  Moreover, since the ventilation path of a thermal radiation part is the structure which has penetrated to a longitudinal direction and has an opening in both ends, an internal cleaning is easy.

  Further, according to the present invention, in the state where the display device stands the display panel and the light guide plate, the substrate is disposed close to the side end surface along the vertical direction of the light guide plate. However, it becomes a vertical direction or a direction close to vertical. Therefore, the air in the ventilation path rises because the specific gravity is reduced by being warmed by the heat from the heat radiating portion. As a result, an updraft naturally occurs in the air passage, and the air in the air passage can be made to flow without using a fan due to the chimney effect. Therefore, since a fan is not required to cool the heat radiating portion, overheating of the light emitting device can be prevented without increasing energy consumption.

  According to the present invention, since the heat radiating part has a plurality of air passages whose penetration directions are parallel to each other, the surface area (specific surface area) per unit volume of the heat radiating part is increased, and the heat radiating effect is improved. In addition, by increasing the number of air passages formed and reducing the cross-sectional area per air passage, the thickness of the heat dissipating part can be reduced without reducing the surface area of the heat dissipating part, thereby reducing the thickness of liquid crystal display devices and the like. Can be achieved.

  Further, according to the present invention, the heat dissipating part further has a plate-like heat dissipating fin having a longitudinal direction in the direction of passage of the air passage on the inner surface of the air passage, so that the surface area of the air passage is increased and the heat dissipating effect is improved. .

  Moreover, according to this invention, since a thermal radiation part further has a 2nd thermal radiation fin in an outer surface, the outer surface area of a thermal radiation part expands and the thermal radiation effect improves.

  According to the present invention, since the back cover portion that covers the back surface of the light guide plate is formed integrally with the heat radiating portion, the heat capacity of the heat radiating portion is increased and the cooling capacity can be improved.

  Further, according to the present invention, the heat absorbing portion is integrally formed with the pressing portion that presses the front surface of the edge of the display panel, so that the heat capacity of the heat absorbing portion increases and the cooling capacity can be improved.

It is the perspective view seen from the back side of the liquid crystal display device 20 to which the light-emitting device 10 which concerns on the 1st Embodiment of this invention is applied. It is sectional drawing which planarly viewed the principal part of the liquid crystal display device 20 to which the light-emitting device 10 which concerns on the 1st Embodiment of this invention is applied. It is a perspective view which shows the principal part of the light-emitting device 10 which concerns on the 1st Embodiment of this invention. It is the perspective view seen from the back side of the state which mounted | wore the liquid crystal display device 20 which applied the light-emitting device 10 which concerns on the 1st Embodiment of this invention with the upper surface cabinet 27 and the back surface cabinet 28. FIG. FIG. 5A relates to the second embodiment of the present invention, and FIG. 5A is a cross-sectional view of the main part of the liquid crystal display device 20 to which the light emitting device 101 according to the present invention is applied, and FIG. ) Is a cross-sectional view of a main part of the liquid crystal display device 20 to which the light emitting device 102 according to another embodiment is applied. FIG. 6A is a plan view showing a schematic configuration of the light-emitting device 103, and FIG. 6B is a schematic configuration of the light-emitting device 104 of another mode according to the third embodiment of the present invention. FIG. FIG. 7A shows a main part of the liquid crystal display device 20 to which the light-emitting device 105 in which the heat-absorbing portion 14 is integrally formed with the pressing portion 14a is applied, according to the fourth embodiment of the present invention. FIG. 7B is a cross-sectional view of the main part of the liquid crystal display device 20 to which the light emitting device 106 in which the back cover portion 15a is integrally formed with the heat radiating portion 15 is seen in plan view. FIGS. 8A to 8C relate to the fifth embodiment of the present invention, and FIG. 8A to FIG. 8C show the key points of the liquid crystal display device 20 to which the light emitting devices 107 to 109 having different shapes in the plan view of the heat radiation portion 15 are applied. It is sectional drawing which planarly viewed the part. FIG. 9 (A) relates to the sixth embodiment of the present invention, and FIG. 9 (A) shows from the back side of the liquid crystal display device 20 that shows a situation in which the fan 40 is provided in the heat radiation portion 15 of the cooling member 13 arranged in the vertical direction. FIG. 9B is a plan view of the main part of the liquid crystal display device 20 to which the light emitting device 10 in which the fan 40 is provided in the heat radiating portion 15 is applied. FIG. 10 is a perspective view according to a seventh embodiment of the present invention, as viewed from the back side of the liquid crystal display device 20, showing a situation in which a fan 40 is provided in the heat dissipation portion 15 of the cooling member 13 arranged in the horizontal direction. It is the perspective view seen from the back side which shows the conventional display apparatus D described in patent document 1. FIG.

(First embodiment)
Hereinafter, an embodiment in which the present invention is applied to a light emitting device 10 constituting an edge light type backlight of a liquid crystal display device 20 as a display device will be described with reference to the drawings. 1 to 4 relate to the first embodiment of the present invention. FIG. 1 is a perspective view of the liquid crystal display device 20 as viewed from the back side, and FIG. 2 is a schematic configuration of the liquid crystal display device 20. FIG. 3 is a perspective view of the main part of the light emitting device 10. FIG. 4 is a perspective view of the liquid crystal display device 20 with the top cabinet 27 and the back cabinet 28 mounted from the back side. FIG. In the following description, the surface corresponding to the display surface side of the liquid crystal display device 20 is referred to as “front surface”, and the opposite surface opposite to this is referred to as “back surface”.

  The liquid crystal display device 20 of the present embodiment is disposed on a display panel 21 including liquid crystal display elements, an optical sheet 22 such as a polarizing sheet disposed on the back side of the display panel 21, and a back side of the optical sheet 22. The light guide plate 23, the back cover 24 that covers the back side of the light guide plate 23, the light emitting device 10 that is disposed in the vicinity of the side end surface 23a of the light guide plate 23, the display panel 21 and the rear edge of the optical sheet 22, and the light emitting device 10 is provided with a frame member 25 that supports the front end portion of 10, and a pressing member 26 that covers the front surface of the end edge portion of the display panel 21 and the side surface of the frame member 25.

  The light guide plate 23 and the light emitting device 10 constitute an edge light type backlight device. Although illustration is omitted, a reflection sheet that reflects incident light toward the display panel 21 may be provided on the back surface of the light guide plate 23.

  The back cover 24 is also called a backlight chassis. The back cover 24 protects the back side of the light guide plate 23 and includes a power supply circuit 30 necessary for operating the liquid crystal display device 20 and a control circuit 31 that performs electrical control. Established. A spacer (not shown) is disposed between the back surface of the light guide plate 23 and the back cover 24, and the back cover 24 and the light guide plate 23 are separated by the spacer.

  Since the frame member 25 holds the positional relationship among the display panel 21, the light guide plate 23, and the light emitting device 10, rigidity and strength are required, and the frame member 25 is in contact with the cooling member 13. It is desirable to have a heat insulating property that does not transmit the absorbed heat to the display panel 21, the optical sheet 22, and the light guide plate 23. Therefore, for example, PC (polycarbonate) resin, ABS (acrylonitrile-butadiene-styrene) resin, or these resins It is made of glass fiber reinforced resin with glass fiber added to it. The frame member 25 prevents light emitted from the side end face 23 a of the light guide plate 23 and light emitted from the light emitting device 10 from leaking to the front side of the display panel 21.

  The pressing member 26 covers and protects the front surface of the edge portion of the display panel 21 and prevents light from leaking therefrom.

  The light emitting device 10 of the present embodiment includes a substrate 11 having a longitudinal direction in the direction along the longitudinal direction of the side end surface 23a of the light guide plate 23, a light source 12 provided on one surface 11a of the substrate 11 facing the light guide plate 23, and A cooling member 13 provided in contact with the other surface 11 b opposite to the one surface 11 a of the substrate 11 and extending in the longitudinal direction of the substrate 11 is included. In the present embodiment, the display panel 21 and the light guide plate 23 are arranged in an upright state, and the substrate 11 is arranged close to the side end face 23 a along the vertical direction of the light guide plate 23. Therefore, the board | substrate 11 and the cooling member 13 are arrange | positioned so that a longitudinal direction may become a perpendicular direction.

  The light source 12 consists of LEDs. The LED may be a white single color LED or a mixture of red, green, and blue LEDs to realize white. In the present embodiment, a plurality of light sources 12 mounted on one substrate 11 is used. However, a plurality of substrates 11 on which one or a small number of light sources 12 are arranged are connected to the side end face 23 a of the light guide plate 23. They may be arranged along the longitudinal direction.

  The cooling member 13 includes a heat absorbing portion 14 that is in contact with the other surface 11 b of the substrate 11 and a heat radiating portion 15 that is provided integrally with the heat absorbing portion 14. In this embodiment, the heat absorption part 14 is a long plate shape, and the heat radiation part 15 is a rectangular tube shape. The heat dissipating part 15 has an air passage 16 penetrating in the direction along the longitudinal direction of the substrate 11, and air vents 16 a and 16 b that are formed at both ends of the air passage 16 and open in the penetrating direction of the air passage 16. . In the present embodiment, since the longitudinal direction of the cooling member 13 is set to the vertical direction, the penetration direction of the air passage 16 is the vertical direction and is linear. Moreover, the planar view shape of the thermal radiation part 15 and vent hole 16a, 16b is a rectangle or a square. The heat radiating part 15 is designed to have a larger heat capacity than the heat absorbing part 14 and to have a surface area that can sufficiently exhibit a heat radiating effect to the outside air.

  The cooling member 13 is preferably made of a material having excellent thermal conductivity and rigidity and corrosion resistance. Examples of such materials include metals such as aluminum, aluminum alloys, copper, and copper alloys, and synthetic resins containing carbon fibers and metal particles. As in this embodiment, when the penetration direction of the air passage 16 is linear, the cooling member 13 can be manufactured by an extrusion molding method. In addition, by manufacturing the cooling member 13 with a highly rigid material and making the heat radiating portion 15 in the shape of a square tube, the support strength on the back side of the display panel 21 is greatly increased compared to the heat sink 6 of Patent Document 1. Therefore, it becomes easy to maintain the flatness of the large-sized liquid crystal display device 20. In some cases, a conventionally used reinforcing member can be omitted.

  Since the cooling member 13 of the present embodiment is formed in a shape in which the plate-like heat absorbing portion 14 is protruded from the heat radiating portion 15, the heat absorbing portion 14 is disposed between the light guide plate 23 and the frame member 25, By disposing the heat dissipating part 15 on the back side of the light guide plate 23, the cooling member 13 can be prevented from increasing the width dimension in the left-right direction of the liquid crystal display device 20.

  Since the cooling member 13 of this embodiment does not include an electronic component or an electric circuit, even if dust or the like enters the ventilation path 16, there is no possibility of causing an electrical short circuit. Therefore, as shown in FIG. 4, when the upper surface cabinet 27 and the rear surface cabinet 28 are attached and the upper surface and the rear surface of the display panel 21 and the light emitting device 10 are covered, the upper end portion of the heat radiation unit 15 is exposed to the upper surface cabinet 27. Thus, the vent 16a of the vent passage 16 can be directly exposed to the outside air. Accordingly, since air does not give resistance when air flows into the air passage 16 and flows out from the air passage 16, the flow of air is facilitated. Furthermore, it is also possible to increase the opening area of the vent holes 16a and 16b to further facilitate the inflow and outflow of air.

  The liquid crystal display device 20 including the light emitting device 10 according to this embodiment configured as described above exhibits the operations and effects described below. When the substrate 11 and the light source 12 of the light emitting device 10 generate heat as the liquid crystal display device 20 is driven, the heat absorbing portion 14 of the cooling member 13 absorbs heat from the substrate 11 and transmits this heat to the heat radiating portion 15. The heat transmitted from the heat absorbing part 14 to the heat radiating part 15 heats the air in the air passage 16. When the air is heated and heated, it expands and the specific gravity decreases. The ventilation path 16 is set in a straight line with a vertical direction. Further, the air passage 16 does not have a structure that gives air flow resistance. Accordingly, the air whose specific gravity is reduced and lightened rises in the air passage 16 and is discharged to the outside from the upper vent 16a. As a result, an upward air flow is easily generated in the air passage 16, and the chimney effect The air flow from the bottom upwards naturally occurs. And when air flows through the inside of the ventilation path 16, the heat of the heat radiation part 15 is continuously deprived and dissipated outside. Since the heat of the substrate 11 is absorbed by the heat absorbing unit 14 and transmitted to the heat radiating unit 15, the heat of the heat radiating unit 15 is dissipated to the outside, whereby the substrate 11 is cooled and the light source 12 on the substrate 11 is also cooled. The

  Thus, since the light emitting device 10 according to the present embodiment can prevent the substrate 11 and the light source 12 from being overheated, in the high-brightness type liquid crystal display device 20 that employs the edge light type backlight device, the light emitting device 10 is overheated. It is possible to solve the problem of damage or deterioration of function. At the same time, the heat generated by the light emitting device 10 can be prevented from adversely affecting the light guide plate 23, the optical sheet 22, and the display panel 21, and the problem of lowering the display quality of the display panel 21 can be solved. In addition, since the light emitting device 10 of the present embodiment has a simple structure that does not use a fan and prevents the substrate 11 and the light source 12 from being overheated, an increase in manufacturing cost and operating cost can be suppressed. Furthermore, since the vent 16a can be exposed to the outside, there is an advantage that cleaning and maintenance are facilitated.

  By the way, the flow of the air in the ventilation path 16 continues while the heat radiating part 15 is higher than the ambient temperature. Further, as the temperature difference between the air in the air passage 16 and the air around the heat radiating portion 15 increases, the flow velocity of the air flowing in the air passage 16 increases. Accordingly, the higher the temperature of the heat radiating portion 15, the larger the temperature rise range of the air in the air passage 16, the air flow rate in the air passage 16 is increased, and the cooling power of the heat radiating portion 15 is increased. That is, the light emitting device 10 of the present embodiment has a function of increasing the cooling power as the heat generation of the substrate 11 increases.

  Further, in the present embodiment, the light emitting device 10 is disposed on both left and right ends of the liquid crystal display device 20, and the heat generated by the light emitting device 10 is dissipated to the outside on both left and right ends. The heat generation of the light emitting device 10 does not affect the power supply circuit 30 and the control circuit 31 that are located between them and are attached to the back cover 24. Therefore, an increase in the ambient temperature of the power supply circuit 30 and the control circuit 31 is suppressed, and the effect of stabilizing these operations is exhibited.

(Second Embodiment)
FIG. 5A is a cross-sectional view of a main part of a liquid crystal display device 20 to which the light emitting device 101 according to the second embodiment of the present invention is applied, and FIG. 5B is a light emitting device 102 according to another aspect. It is sectional drawing which planarly viewed the principal part of the liquid crystal display device 20 to which this is applied. In each of the embodiments described later, the description of the configuration common to the first embodiment is omitted.

  The light emitting devices 101 and 102 according to the present embodiment are characterized in that a plurality of ventilation paths 16 whose penetration directions are parallel to each other are formed in the heat dissipation portion 15 of the cooling member 13. In the embodiment shown in FIG. 5A, two parallel ventilation paths 16 are formed in the heat radiating portion 15, and in the embodiment shown in FIG. 5B, five parallel ventilation paths 16 are formed. .

  By forming a plurality of air passages 16, the necessary total surface area of the air passages 16 can be ensured even if the cross-sectional area per one of the air passages 16 is reduced, so that the thickness dimension T of the heat radiation portion 15 is reduced. be able to. Further, as the number of the air passages 16 formed is increased, it is easier to secure a necessary surface area and to reduce the thickness dimension T of the heat radiation part 15. Therefore, the thin liquid crystal display device 20 can be provided without reducing the cooling capacity of the cooling member 13.

  Note that, when a plurality of air passages 16 are formed without reducing the cross-sectional area, the surface area of the heat radiating portion 15 is increased, so that the effect of improving the cooling capacity of the cooling member 13 is exhibited.

(Third embodiment)
FIG. 6A is a plan view showing a schematic configuration of a light emitting device 103 according to the third embodiment of the present invention, and FIG. 6B is a plan view showing a schematic configuration of a light emitting device 104 of another mode. . The object of the present embodiment is to improve the heat dissipation performance of the heat dissipation portion 15. In the embodiment shown in FIG. 6A, a plurality of plate-like heat radiation fins 17 are formed on the inner side surface 16S of the air passage 16, and the embodiment shown in FIG. A second radiating fin 18 is further formed on the side surface 15S.

  The radiating fins 17 formed on the inner side surface 16S of the air passage 16 are preferably in the form of a plate whose longitudinal direction is the penetration direction of the air passage 16 so that air flow in the air passage 16 is not hindered. The second heat dissipating fins 18 formed on the outer surface 15S of the heat dissipating part 15 do not need to consider the air fluidity, so the shape is not particularly limited, and may be a plate shape or a rod shape. However, when manufacturing the cooling member 13 by an extrusion molding method, it is preferable that the 2nd radiation fin 18 is also made into the shape extended in a longitudinal direction.

  What is necessary is just to determine suitably the cross-sectional shape, width dimension, formation interval, formation number, etc. of the radiation fin 17 and the 2nd radiation fin 18 according to the implementation condition. In the embodiment of FIG. 6, the planar cross sections of the radiation fins 17 and the second radiation fins 18 are rectangular, but they may be triangular. Further, the protruding length from the inner side surface 16S of the radiating fin 17 and the protruding length from the outer side surface 15S of the second radiating fin 18 may not be constant and may be changed partially or periodically. Good.

  Thus, by forming the radiation fins 17 or the second radiation fins 18 in the heat radiation part 15, the surface area of the heat radiation part 15 can be increased and the heat radiation performance can be improved. Moreover, since the specific surface area of the heat radiating part 15 is increased by forming the heat radiating fins 17 or the second heat radiating fins 18, it is possible to reduce the plan view size of the heat radiating part 15 for obtaining a necessary heat radiating area. It becomes.

(Fourth embodiment)
FIG. 7 relates to a fourth embodiment of the present invention, and FIG. 7A is a schematic diagram of a liquid crystal display device 20 to which a light emitting device 105 in which a holding portion 14a is integrally formed with a heat absorbing portion 14 is applied. 7B is a cross-sectional view of the main part of the liquid crystal display device 20 to which the light-emitting device 106 in which the back cover portion 15a is integrally formed with the heat radiating portion 15 is seen in plan view. In the present embodiment, the light emitting devices 105 and 106 having the heat radiating fins 17 and the second heat radiating fins 18 are used on the outer side surface 15S and the inner side surface 16S of the heat radiating part 15, but the heat radiating fins 17 and the second heat radiating fins 18 are used. Is optional and can be omitted.

  In the embodiment shown in FIG. 7A, the heat absorbing portion 14 of the light emitting device 105 is integrally formed with a pressing portion 14 a that holds the front surface of the side edge of the display panel 21 and the front end surface of the frame member 25. With this configuration, the heat capacity and the surface area of the heat absorbing portion 14 are increased, so that the ability to absorb the heat of the substrate 11 is improved.

  In the embodiment shown in FIG. 7B, the heat radiation part 15 of the light emitting device 106 is integrally formed with a back cover part 15 a that protects the back surface of the light guide plate 23. Since the surface area is enlarged, the heat radiation capability of the heat radiation portion 15 is improved.

(Fifth embodiment)
FIG. 8 relates to the fifth embodiment of the present invention, and FIGS. 8A to 8C show liquid crystal displays to which light emitting devices 107 to 109 having different shapes of the heat radiation part 15 in plan view are applied. FIG. 3 is a cross-sectional view of the main part of the device 20 as viewed from above.

  In the light emitting device 107 shown in FIG. 8A, the heat dissipating portion 15 has a right triangle shape in plan view, and heat dissipating fins 17 are formed on the inner surface of the air passage 16. In the light-emitting device 108 illustrated in FIG. 8B, the planar view shape of the heat dissipation portion 15 is a semi-elliptical shape. In the light-emitting device 109 illustrated in FIG. 8C, the shape of the heat radiation unit 15 in plan view is a quarter circle or a quarter ellipse. Thus, the planar view shape of the heat radiating part 15 and the ventilation path 16 of the light emitting devices 10 and 101 to 109 according to the present invention can be appropriately changed according to the situation of implementation.

(Sixth embodiment)
FIG. 9 relates to the sixth embodiment of the present invention, and FIG. 9A shows a liquid crystal display device 20 in which a fan 40 is provided in the heat radiation portion 15 of the cooling member 13 arranged in the vertical direction. FIG. 9B is a plan view of the main part of the liquid crystal display device 20 to which the light emitting device 10 in which the fan 40 is provided in the heat radiating portion 15 is applied.

  In the present embodiment, a fan 40 is attached to one vent 16a of the heat radiating section 15 of the cooling member 13 arranged in the vertical direction so that the air in the vent path 16 is forced to flow. The direction of penetration of the air passage 16 is straight, and there is no member that provides air flow resistance inside. Further, by providing the fan 40, the possibility that dust or the like is sucked into the air passage 16 is increased. However, since there are no electrical components or the like in the air passage 16, it is not necessary to attach a filter or the like to the air vent. Therefore, the air in the ventilation path 16 can be efficiently flowed by the fan 40, and a cooling capability can be improved significantly. Moreover, since the air flow resistance in the air passage 16 is small, the low-power fan 40 can be used, and an increase in power consumption can be suppressed.

(Seventh embodiment)
FIG. 10 relates to the seventh embodiment of the present invention, and is a perspective view seen from the back side of the liquid crystal display device 20 showing a situation in which the fan 40 is provided in the heat radiation portion 15 of the cooling member 13 arranged in the horizontal direction. FIG.

  In the present embodiment, the light emitting device 10 is disposed close to the upper and lower side end surfaces of the light guide plate 23, and as a result, as shown in FIG. 10, the heat radiating portion 15 of the cooling member 13 is horizontal in the longitudinal direction. It is intended for the case where it is arranged in a direction. As described above, even when the longitudinal direction of the cooling member 13 is horizontal, the fan 40 is attached to one of the vent holes 16a of the heat radiating portion 15 so that the air in the air passage 16 can be efficiently flowed, and an excellent cooling effect can be obtained. It is possible to demonstrate.

DESCRIPTION OF SYMBOLS 10 Light-emitting device 11 Board | substrate 11a One side 11b The other side 12 Light source 13 Cooling member 14 Heat absorption part 14a Holding part 15 Heat radiation part 15a Back cover part 16 Air flow path 16a Vent hole 16b Vent hole 17 Radiation fin 18 Second heat radiation fin 20 Liquid crystal display Device 21 Display panel 22 Optical sheet 23 Light guide plate 23a Side end face 24 Back cover 25 Frame member 26 Holding member

Claims (7)

A display panel;
By projecting light to the side end surface of the back side light guide plate disposed on the display panel, a display device and a light emitting device for irradiating light to the display panel from the back side,
The light emitting device
A substrate disposed in the vicinity of the side end surface of the light guide plate and having a direction along the longitudinal direction of the side end surface as a longitudinal direction;
A light source provided on one side of the substrate facing the light guide plate;
A cooling member provided in contact with the other surface opposite to the one surface of the substrate and extending in the longitudinal direction of the substrate ;
An endothermic part that contacts the other surface and absorbs heat of the substrate;
A heat dissipating part that is provided integrally with the heat absorbing part and dissipates the heat absorbed by the heat absorbing part to the outside, and passes through the air passage in the direction along the longitudinal direction of the substrate, and at both ends of the air passage a display device formed have a vent port opening to the through direction of the vent passage, characterized in that it comprises a cooling member having a cylindrical heat radiation member for supporting the back side of the display panel. In a state of being erected in front Symbol display panel and the light guide plate, wherein the substrate, the display device according to claim 1, characterized in that it is arranged close to the side end face along the vertical direction of the light guide plate. The display device according to claim 1, wherein the heat radiating section has a plurality of air passages whose penetration directions are parallel to each other. The said thermal radiation part further has the plate-shaped thermal radiation fin which makes the penetration direction of the said ventilation path a longitudinal direction in the inner surface of the said ventilation path, The Claim 1 characterized by the above-mentioned. Display device . The display device according to claim 1, wherein the heat radiating portion further includes a second heat radiating fin on an outer surface. The display device according to claim 1, wherein a back cover portion that covers a back surface of the light guide plate is formed integrally with the heat radiating portion. The display device according to claim 1, wherein the heat absorbing portion is integrally formed with a pressing portion that presses the front surface of the edge portion of the display panel.