JP2006302581A - Heat sink device, backlight device, and image display device of luminescence unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat sink device of a thin structure effectively dissipating heat generated from a number of light-emitting diodes. <P>SOLUTION: The heat sink device of the luminescent unit is structured of: a light-emitting unit mounting a light-emitting body; a chassis for fitting the light-emitting unit; a heat-radiating means for releasing heat; and a high heat-transfer device for transferring heat from the luminescent body to the heat-radiating means, and also is so structured to have a concave part fitted to the chassis for containing the high heat-transfer device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image display device (LCD: Liquid Crystal Display) using, for example, a transmissive liquid crystal panel, a backlight device used therefor, and a heat dissipation device attached to the backlight device.

  The liquid crystal display device has a larger display screen, lighter weight, thinner thickness, lower power consumption, etc., compared with a cathode ray tube (CRT), for example, a self-luminous PDP (Plasma Display). Panel) and the like are used for television receivers and various displays. A liquid crystal display device encapsulates liquid crystal between two transparent substrates of various sizes, and changes the light transmittance by changing the direction of liquid crystal molecules by applying a voltage to optically display a predetermined image or the like. A liquid crystal panel is provided.

  Since the liquid crystal display device is not a light emitter, the liquid crystal display device includes a backlight unit that functions as a light source, for example, on the back surface of the liquid crystal panel. The backlight unit includes, for example, a primary light source, a light guide plate, a reflective film, a lens sheet, or a diffusion film, and supplies display light to the entire liquid crystal panel. In the backlight unit, a cold cathode fluorescent lamp (CCLF: Cold Cathode Fluorescent Lamp) in which mercury or xenon is enclosed in a fluorescent tube is used as a primary light source. There is a problem such as equality due to the lifetime or the presence of a low-luminance region on the cathode side.

  By the way, in a large sized liquid crystal display device, an area light type backlight (Area Litconfiguration Backlight) device that generally arranges a plurality of long cold cathode fluorescent lamps on the back of a diffusion plate and supplies display light to a liquid crystal panel. Is provided. Such area light type backlight devices are also required to solve the above-mentioned problems of the cold cathode fluorescent lamp, and particularly in a large television receiver exceeding 40 inches, there are problems of high brightness and high saturation. It has become more prominent.

On the other hand, in the area light type backlight device, instead of the cold cathode fluorescent lamp described above, an LED that obtains white light by two-dimensionally arranging a large number of light emitting diodes (LEDs) on the back side of the diffusion film. An area light type backlight has been attracting attention (Patent Document 1). Such an LED backlight device is designed to reduce the cost of the LED as well as to display a high-luminance image or the like on a large liquid crystal panel with low power consumption.
Japanese Patent Laid-Open No. 7-191311

  By the way, in an LED backlight device, a large amount of heat is generated from these LEDs by providing a large number of LEDs. Since the LED backlight device is combined with a sealed space portion on the back surface of the liquid crystal panel, the generated heat is trapped in the sealed space portion to increase the temperature of the display device. As a result, the display panel is normal. Cannot display. In addition, the LED backlight device is provided with the diffusion film and the reflection film as described above, and there has been a problem that the display accuracy is deteriorated due to deformation or alteration of these optical films caused by high temperature. .

  Therefore, in the LED backlight device, a heat radiating means for radiating heat generated from the LED is provided. In LED backlight devices, for example, cooling air can be sent by a cooling fan to take measures to dissipate the generated heat, but the cooling air is sent to the LED that is the light source due to vibration and blurring. It is not possible to adopt a direct spraying configuration.

  Therefore, in the LED backlight device, a heat dissipation structure is employed in which heat is generated by conducting generated heat from a sealed space portion to a heat sink formed of, for example, an aluminum material by an appropriate heat conductive member. In the LED backlight device, it is impossible to directly arrange the heat conduction member in the sealed space part to block the display light, to efficiently and uniformly dissipate the heat in the sealed space part, the heat sink and the shortest path Conditions such as coupling and efficient heat dissipation are required, and there has been a problem that the structure of the apparatus becomes complicated in order to realize these conditions. Further, in the LED backlight device, when the liquid crystal panel has a non-uniform temperature distribution over the entire surface without accurately radiating heat, a phenomenon such as color unevenness occurs.

  Therefore, in the LED backlight device having the light emitting block 111 on which the LED 112 is mounted as shown in FIG. 11, the heat pipe 125 is used as a high heat transfer device, and the heat generated by the LED 112 is radiated by the heat radiating means via the heat pipe 125. A structure in which heat is conducted by conduction to a certain heat sink 126 is employed. However, in such a structure, the holding member 124 for holding the heat pipe 125 at a predetermined position is necessary. Further, since the heat generated in the LED 112 is conducted to the heat pipe 125 through the holding member 124, there arises a problem that heat conduction is not smoothly performed due to the thermal resistance of the holding member 124. Furthermore, since the heat pipe 112 and its holding member 124 exist between the LED 112 and the back panel 109, there is a problem that the LED backlight device cannot be thinned.

  Accordingly, an object of the present invention is to provide a thin heat dissipation device that efficiently dissipates heat generated from a light emitting diode. In addition, the present invention aims to increase the brightness of the display panel by providing a large number of light-emitting diodes, and also efficiently dissipate heat generated from the light-emitting diode groups so that the temperature distribution is uniform over the entire surface of the display panel. An object of the present invention is to provide a backlight device and an image display device that are made thin and thin.

A heat-radiating device for a light-emitting unit according to the present invention includes a light-emitting unit on which a light-emitting body is mounted, a housing for mounting the light-emitting unit, a heat-dissipating unit for releasing heat, and a heat-dissipating unit that dissipates heat from the light-emitting unit. And a high heat transfer device for conducting heat to the housing, and a housing is provided with a recess for housing the high heat transfer device.
Preferably, it is set as the structure which provides the recessed part for accommodating a high heat-transfer device in a thermal radiation means.
Preferably, the direction along the longitudinal direction of the recess provided in the heat dissipation means and the direction of the heat dissipation groove provided in the heat dissipation means are the same direction.

  A backlight device according to the present invention supplies display light from the back side of a display panel in combination with a transmissive display panel, and is a light emitting unit in which a large number of light emitting diodes are mounted on a wiring board. And a back panel for mounting the light emitting unit, a heat dissipating means for releasing heat, and a high heat transfer device for conducting heat from the light emitter to the heat dissipating means. It is set as the structure which provides the recessed part for accommodating a device.

  An image display device according to the present invention includes a transmissive display panel, a light emitting unit in which a number of light emitting diodes are mounted on a wiring board, a back panel for mounting the light emitting unit, and a heat radiating means for releasing heat. And a high heat transfer device for conducting heat from the light emitting diode group to the heat radiating means, and a recess for accommodating the high heat transfer device is provided on the back panel.

  According to the heat radiating device of the light emitting unit according to the present invention, the high heat transfer device is held by the casing, so that the device can be reduced in thickness and weight, and the device can be manufactured at low cost. Further, the heat from the light emitter can be efficiently radiated.

  According to the backlight device according to the present invention, since the high heat transfer device is held by the casing, the backlight device can be thinned. In addition, since the heat generated from the LEDs can be efficiently radiated, substantially uniform display light can be supplied over the entire surface to the transmissive display panel.

  According to the image display device of the present invention, since the high heat transfer device is held by the casing, the image display device can be thinned. In addition, since the heat generated from the LED can be efficiently radiated, by setting the transmissive display panel to a substantially uniform temperature over the entire surface, it is possible to prevent the occurrence of color unevenness and display a stable image. .

  Hereinafter, a transmissive liquid crystal display panel 1 shown in the drawings as an embodiment of the present invention will be described in detail. The transmissive liquid crystal display panel 1 is used for a display panel of a television receiver having a large display screen of 40 inches or more, for example.

  As shown in FIGS. 1 and 2, the transmissive liquid crystal display panel 1 includes a liquid crystal panel unit 2 and a backlight unit 3 that is combined with the back side of the liquid crystal panel unit 2 to supply display light. . The liquid crystal panel unit 2 includes a frame-shaped front frame member 4, a liquid crystal panel 5, and a frame-shaped back frame member 6 that holds the outer peripheral edge of the liquid crystal panel 5 with the front frame member 4.

  Although not described in detail, the liquid crystal panel 5 encloses a liquid crystal between a first glass substrate and a second glass substrate, which are held at an opposing interval by spacer beads or the like, and applies a voltage to the liquid crystal to apply liquid crystal. Change the light transmittance by changing the direction of the molecule. In the liquid crystal panel 5, a striped transparent electrode, an insulating film, and an alignment film are formed on the inner surface of the first glass substrate. In the liquid crystal panel 5, three primary color filters, an overcoat layer, a striped transparent electrode, and an alignment film are formed on the inner surface of the second glass substrate. In the liquid crystal panel 5, a deflection film and a retardation film are bonded to the surfaces of the first glass substrate and the second glass substrate.

  In the liquid crystal panel 5, an alignment film made of polyimide is arranged in a horizontal direction with liquid crystal molecules at the interface, and the deflection film and the retardation film are achromatic and whitened to achieve full color using a color filter. Etc. are displayed in color. In addition, about the liquid crystal panel 5, it is not limited to this structure, A liquid crystal panel provided with the various structure provided conventionally may be sufficient.

  The backlight unit 3 includes a light emitting unit 7 that is disposed on the back side of the liquid crystal panel unit 2 and supplies display light, a heat radiating unit as a heat radiating device that radiates heat generated in the light emitting unit 7, and these A back panel 9 as a housing that holds the light emitting unit 7 and the heat radiating unit and is combined with the front frame member 4 and the rear frame member 6 is provided. The backlight unit 3 has an outer dimension that is opposed to the entire rear surface of the liquid crystal panel unit 2 and is combined in a state where the opposed space portions facing each other are optically sealed.

  The first main surface 9d facing the liquid crystal panel 5 side of the back panel 9 is provided with a heat pipe 25 as a high heat transfer device and a plurality of light emitting arrays 11 on which LEDs 12 as light emitters are mounted. . Further, heat sinks 26 as heat radiating means are provided on the surface of the back panel 9 that faces the first main surface 9d, and the heat sinks 26 are provided at both ends of the back panel 9 in the longitudinal direction.

  A heat radiating unit as a heat radiating device includes a heat pipe as a high heat transfer device, a heat sink 26 to which both ends of the heat pipe 25 are connected, a cooling fan 27 for promoting a cooling function of the heat sink 26, and the like. . The high heat transfer device is not limited to a heat pipe as long as it can conduct heat efficiently.

  The heat pipe 25 is a member generally used for conducting heat from a high-temperature power supply unit or the like to various heat dissipating means in various electronic devices, and is a metal such as copper or aluminum having excellent heat conductivity. It is configured by enclosing a conductive medium such as water that is vaporized at a predetermined temperature in a state where the inside of the pipe-making material is evacuated, and has a highly efficient heat conduction capability.

  The backlight unit 3 includes an optical sheet block 10 and a light emitting unit 7 having a light emitting block 11 on which a light emitting diode (hereinafter referred to as LED) 12 as a light emitter is mounted. The optical sheet block 10 is installed facing the back side of the liquid crystal panel 5, and details thereof are omitted. For example, the optical sheet block 10 is formed by laminating various optical function sheets such as a polarizing film, a retardation film, a prism sheet, or a diffusion film. The optical sheet laminate 13, the diffusion light guide plate 14, the diffusion plate 15, the reflection sheet 16, and the like are included.

  Although not described in detail, the optical sheet laminate 13 is a functional sheet that decomposes the display light supplied from the light emitting unit 7 and incident on the liquid crystal panel 5 into orthogonal polarization components, and compensates for the phase difference of the light wave and wide-angle viewing angle. A plurality of optical function sheets having various optical functions such as a function sheet for preventing the coloration and coloring or a function sheet for diffusing display light are laminated. The optical sheet laminate 13 is not limited to the above-described optical function sheet, and includes, for example, a brightness enhancement film for improving brightness, two upper and lower diffusion sheets sandwiching a retardation film and a prism sheet, and the like. Also good.

  In the optical sheet block 10, the diffusion light guide plate 14 is disposed on the main surface side facing the liquid crystal panel 5 of the optical sheet laminate 13, and the display light supplied from the light emitting block 11 is incident from the back side. The diffusion light guide plate 14 is made of a slightly thick plate body formed of a transparent synthetic resin material having a light guide property, such as an acrylic resin or a polycarbonate resin. The diffusion light guide plate 14 guides the display light incident from one main surface side while diffusing and reflecting the display light inside, and makes the light incident on the optical sheet laminate 13 from the other main surface side. The diffusion light guide plate 14 is laminated on the optical sheet laminate 13 as shown in FIG. 2, and is attached to the outer peripheral wall portion of the back panel 9 via a bracket member.

  In the optical sheet block 10, a large number of optical stud members 17 allow the opposing distance between the diffusion plate 15 and the reflection sheet 16 and the opposing distance between the diffusion plate 15 and the diffusion light guide plate 14 to be a predetermined distance. And attached to the back panel 9. The diffusion plate 15 is a plate material formed of a milky white light-transmitting synthetic resin material, for example, an acrylic resin, and the display light supplied from the light emitting block 11 is incident thereon. A large number of light control dots 15 a arranged in an array are formed on the diffusion plate 15 so as to face the plurality of LEDs 12 of the light emitting blocks 11 arranged in an array as will be described in detail later.

  The diffusing plate 15 has a dimming dot 15a with a circular dot pattern formed on the surface of the plate by screen printing or the like using ink mixed with a light-shielding agent such as titanium oxide or barium sulfide or a diffusing agent such as glass powder or silicon oxide. It is formed by printing. The diffusion plate 15 blocks the display light supplied from the light emitting block 11 by the light control dots 15a and makes the light incident. The diffusion plate 15 diffuses the display light incident therein and emits it to the diffusion light guide plate 14. The diffusion plate 15 is formed with the dimming dots 15a facing the respective LEDs 12, thereby suppressing the direct increase of the brightness due to the direct display light incident from the respective LEDs 12, thereby making the incident light uniform. The light is emitted to the optical sheet laminate 13.

  In the optical sheet block 10, as described above, the display light emitted from each LED 12 is radiated to the surroundings, so that the display light is directly incident on the diffusion light guide plate 14 and the luminance is not partially increased. It is configured as follows. In the optical sheet block 10, the light efficiency is improved by reflecting the display light radiated to the periphery to the diffusion light guide plate 14 side by the reflection sheet 16. The reflection sheet 16 is formed of, for example, a foamable PET (polyethylene terephthalate) material containing a fluorescent agent. The foamable PET material has a high reflectivity characteristic of about 95%, and has a characteristic that a scratch on the reflecting surface is not noticeable with a color tone different from the metallic luster color. The reflection sheet 16 is also formed of, for example, silver, aluminum, stainless steel or the like having a mirror surface.

  The optical sheet block 10 causes a part of the display light emitted from each LED 12 to be reflected on the surface of the diffusion plate 15 when it is incident on the diffusion plate 15 beyond the critical angle. In the optical sheet block 10, reflected light from the surface of the diffusing plate 15 and part of the display light radiated from each LED 12 to the surroundings and reflected by the reflecting sheet 16 are between the diffusing plate 15 and the reflecting sheet 16. By repeating reflection, the reflectance is improved by the principle of increased reflection.

  The optical sheet block 10 includes a large number of optical stud members 17, and the optical stud members 17 accurately maintain the parallelism between the main surfaces of the diffuser plate 15 and the reflective sheet 16 facing each other. At the same time, the diffusion plate 15 and the diffusion light guide plate 14 are configured so that the parallelism between the main surfaces facing each other is accurately maintained over the entire surface. The optical stud member 17 is a member formed integrally with a milky white synthetic resin material having a light guide property, mechanical rigidity, and a certain degree of elasticity, such as a polycarbonate resin, and is attached to a mounting portion formed integrally with the back panel 9. It is attached.

  In the backlight unit 3, by providing the optical sheet block 10 described above, display light emitted from each LED 12 of the light emitting block 11 is efficiently incident on the liquid crystal panel unit 2 in a stable state. To do. As shown in FIG. 3, the light emitting block 11 includes a plurality of light emitting arrays 11 </ b> A to 11 </ b> F arranged in the lateral direction on the first main surface 9 d of the back panel 9. Moreover, each light emitting array 11 is comprised by the light emission block body (18A-18C) A- (18A-18C) F which mentions the detail arrange | positioned in the length direction later, respectively. Note that the light emitting block bodies (18A to 18C) A to (18A to 18C) F are collectively referred to as the light emitting block body 18 except when individually described in the following description.

  As shown in FIG. 3, the light-emitting blocks 11 in the light-emitting unit 7 are arranged in the light-emitting array 11 in the first row with the light-emitting block bodies 18AA to 18AC arranged in the length direction. In the light emitting blocks 11, the light emitting block bodies 18 are arranged in the length direction of the other light emitting arrays 11 in the same manner by alternately changing the directions of the wiring boards 19. A large number of LEDs 12 are mounted on the light-emitting block 18 by arranging red LEDs, green LEDs, and blue LEDs in an appropriate number on the first main surface 19 a of the wiring board 19 on the same axis. .

  As shown in FIG. 6, each light emitting block body 18 includes a plurality of red LEDs, green LEDs, and blue LEDs (collectively referred to as LEDs 12), and these LEDs 12 are arranged in a longitudinal direction on the first main surface 19 a. It is comprised from the rectangular-shaped wiring board 19 mounted in order. Each light-emitting block body 18 has a large number of LEDs 12 mounted on each wiring board 19 by combining an appropriate number of red LEDs, green LEDs, and blue LEDs. Therefore, the light emitting block 11 is provided with an LED 12 in which the LEDs mounted for each light emitting array 11 are added. In the light emitting block 11, the number of the light emitting block bodies 18 and the number of the LEDs 12 mounted on each of the light emitting block bodies 18 are appropriately determined according to the size of the display screen, the light emission capability of each LED 12, and the like.

  Although not shown, the light emitting block body 18 is formed with a wiring pattern for connecting the LEDs 12 in series, lands for connecting the terminals of the LEDs 12, and the like on the first main surface 19 a of the wiring board 19. Each wiring board 19 is formed with the same specifications, and is located on both sides in the longitudinal direction, and is mounted with a first connector 20A on the signal output side and a second connector 20B on the signal input side. The first connector 20A is a signal output connector and has, for example, a 6-pin structure although details are omitted. The second connector 20B is a signal input connector and has a 5-pin structure, for example, although details are omitted.

FIG. 4 is an enlarged view of the vicinity of the ends of the light emitting arrays 11A and 11B constituting the optical block 11 in the light emitting unit 7 shown in FIG.
A heat pipe 25 and a heat sink 26 are provided on the surface side (back side) of the light emitting block body 18 facing the first main surface 19a of the wiring board 19. A skirt portion 26 a as a fitting portion formed in a part of the heat sink 26 is fitted into a fitting hole 9 b provided in the first main surface 9 d of the back panel 9. Moreover, the heat pipe 25 is accommodated in the recessed part 26b for accommodating the heat pipe 25 formed in the heat sink 26, and the heat pipe 25 is an engagement part formed at the opening side end part of the recessed part 26b. The protrusion 26c is held in the recess 26b of the heat sink 26.

FIG. 5 is a YY sectional view of the light emitting array 11B shown in FIG.
The LED 12 is mounted on the first main surface 19a of the wiring board 19, the light emitting element 12a is held by the resin holder 12b, and the terminal 12c is drawn from the resin holder 12b. The back panel 9, the heat pipe 25, and the heat sink 26 are provided on the second main surface 19c side facing the first main surface 19a of the wiring board.

  The back panel 9 is formed with a hole 9b as a fitting portion for fitting the heat sink 26 together. The heat sink 26 has a large number of fins 26e for efficiently cooling the heat conducted from the heat pipe 25, and a groove 26d as a ventilation path is formed between the fins 26e. On the side opposite to the side having the fins 26 e of the heat sink 26, a skirt portion 26 a that fits into a hole 9 b provided in the back panel 9 is integrally formed. Further, a recess 26b for accommodating the heat pipe 25 is formed, and a protruding engagement portion 26c for holding the heat pipe stored along the opening-side end of the recess is provided. .

  The heat pipe 25 is accommodated in a recessed portion 26b provided in the heat sink 26, and is held in the recessed portion 26b of the heat sink by an engagement protrusion 26c provided along an opening side end portion of the recessed portion. Here, the bottom surface 26a of the heat sink is provided on the back panel 9 so that the main surface of the bottom portion 26a provided on the heat sink 26 and the first main surface 9d of the back panel 9 are substantially the same height. It is fitted in the hole 9b.

  The surface of the heat sink 26 opposite to the side on which the fins 26 e are provided contacts the second main surface 9 e of the back panel 9, and the skirt portion 26 a of the heat sink 26 and the second main surface 19 c of the wiring board 19 Are assembled so that they touch. At the same time, the upper part of the heat pipe 25 held in the recess 26b of the heat sink is also assembled so as to contact the second main surface 19c of the wiring board. Thus, a part of the heat pipe 25 is in direct contact with the wiring board 19 on which the LED 12 is mounted, so that heat generated in the LED 12 can be efficiently conducted to the heat pipe 25. The wiring board 19 on which the plurality of LEDs 12 are mounted is attached to the back panel 9 with screws or the like (not shown) in the arrangement state described above.

FIG. 7 is a view showing a state where the light emitting block 11 is removed from the light emitting unit 7 shown in FIG.
The plurality of heat pipes 25 are arranged at equal intervals so as to be parallel to the longitudinal direction of the back panel 9 while being housed in a recess 9a provided on the first main surface 9d of the back panel. In the vicinity of both end portions of the back panel 9 in the longitudinal direction, the heat pipe 25 and the heat sink 26 are connected to each other via a skirt portion 26a. In addition, in each recess 9 a provided in the back panel 9, two heat pipes 25 a and 25 b connected to the heat sink 26 are accommodated, and the heat pipes 25 a and 25 b are arranged in the longitudinal direction of the back panel 9. It is housed so as to be symmetrical with respect to the center line. Thus, the efficiency of the operation | work which attaches the heat pipe 25 to the back panel 9 can be improved by comprising the heat pipe accommodated in the one dent part 9a by multiple pieces.

FIG. 8 is an enlarged view of an end portion in the longitudinal direction of the back panel 9 shown in FIG.
A hole 9 b formed in accordance with the shape of the bottom part 26 a provided in the heat sink 26 is provided in the first main surface 9 d of the back panel 9. Further, the first main surface 9d is provided with a recess 9a for accommodating the heat pipe 25 so as to be connected to the hole 9b. The shape of the recess 9a is formed in accordance with the shape of the heat pipe 25, and in the present embodiment, the cross-sectional shape of the recess 9a is formed in a hemispherical shape. In addition, tongue-shaped projections 9c are provided at predetermined intervals as engaging members for holding the accommodated heat pipe 25 in the recess 9a at a part of the opening side end of the recess 9a. ing.

  As described above, the heat sink 26 is provided with the skirt portion 26a for fitting with the hole 9b. The skirt portion 26a has a rectangular shape, and the shape is formed so as to match the shape of the hole 9b provided in the back panel 9. The heat sink 26 is provided with a recess 26b for storing the heat pipe 25 along the center line in the short direction of the skirt 26a. In addition, a protrusion 26c for holding the heat pipe 25 in the recessed portion 26b is formed at the end of the recessed portion 26b on the opening side along the longitudinal direction of the skirt portion 26a.

  In a state where the skirt portion 26a of the heat sink 26 is attached to the back panel 9, the dent portion 9a provided on the back panel 9 and the dent portion 26b provided on the skirt portion 26a of the heat sink are connected. The heat pipe 25 is attached across the recess 9a and the recess 26b.

  Therefore, according to the heat dissipation device of the optical unit of the present embodiment, the heat generated in the LED 12 is conducted to the heat pipe 25 through the wiring board 19, and the heat conducted to the heat pipe 25 is the end of the heat pipe. The heat is directly transferred to the heat sink 26 connected to the heat sink 26 and is radiated by the fins 26e provided on the heat sink 26.

Next, a procedure for attaching the heat pipe 25 and the heat sink 26 to the back panel 9 will be described.
First, the end of the heat pipe 25 is placed in a recess 26 b provided in the heat sink 26, and the engaging portion 26 c provided in the heat sink 26 is caulked to attach the end of the heat pipe 25 to the heat sink 26. . Next, in a state where the heat pipe 25 is attached to and held on the heat sink 26, a portion other than the heat pipe 25 attached to the heat sink 26 is placed in the recess 9a provided on the first main surface 9d of the back panel 9. The heat pipe 25 and the heat sink 26 are attached to the back panel 9 by fitting the hem 26 a formed in the heat sink 26 into the hole 9 b provided in the back panel 9. Then, by crimping the engaging portion 9 c provided on the back panel 9, the heat pipe 25 is held in the recessed portion 9 a of the back panel, and the heat pipe 25 and the heat sink 26 are fixed to the back panel 9.

  Next, in this state, a predetermined pressure is applied to the engagement portion 9c of the back panel, the engagement portion 26c of the heat sink, and the heat pipe 25 as a whole. By applying pressure, a flat portion is formed on the upper portion of the heat pipe 25, and a contact area between the heat pipe 25 and the wiring board 19 of the light-emitting block body 18 attached to the back panel 9 is increased. The conductivity at the time when heat generated by the light emitting diode 12 mounted on 19 is transferred to the heat pipe 25 is improved. Finally, each light-emitting array 11 constituting the light-emitting block 11 is fixed to the back panel 9 with screws or the like so as to cover the heat pipe 25 attached to the back panel 9 and the skirt portion 26a of the heat sink.

FIG. 9 illustrates a state of the second main surface 9e facing the first main surface 9d of the back panel 9.
As described above, the heat sinks 26 are provided at both ends in the longitudinal direction of the back panel 9. The heat sink 26 is a member having a large surface area by integrally forming a large number of fins 26e with an aluminum material having excellent thermal conductivity. The heat sink 26 receives heat conduction from the high temperature part side and dissipates heat from the surface of each fin 26e, thereby cooling the high temperature part. The heat sink 26 is provided with a cooling fan 27 at an appropriate position. The cooling fan sucks outside air and blows air to the groove portions 26 d existing between the fins 26 e of the heat sink 26 to cool the heat sink 26. Further, a protective cover 32 is provided between the heat sinks 26 provided at both ends of the second main surface 9e, and various control circuit boards, their packages 31 and the like are mounted thereon.

  According to the heat radiating device of the light emitting unit according to the present embodiment, the heat generated by the light emitting diode 12 performing the lighting operation can be efficiently conducted to the heat radiating means provided in another place by the heat pipe 25. . Further, without providing a heat radiating means directly in the light emitting section, it is possible to obtain a light emitting unit 7 that maintains stable operation and emits light with high brightness even if it includes a large number of light emitting diodes 12 as light sources. In addition, the number of members that cause thermal resistance can be reduced, and heat generated by a large number of light emitting diodes 12 can be efficiently conducted to the heat pipe 25, and the heat dissipation device can be made thin by reducing the number of members. . Furthermore, since the member for holding the heat pipe 25 is eliminated, the work efficiency of assembling the apparatus can be improved and the cost can be reduced.

  According to the cooling device for the optical unit according to the present embodiment, since the heat pipe 25 is held by the recess 9a provided in the back panel 9, a special member for holding the heat pipe 25 in the cooling device is not necessary. The weight of the device is reduced and the device can be manufactured at a low cost.

  Further, according to the backlight device of the present embodiment, a backlight unit including a large number of light emitting diode groups 12 as a light source is used to supply a high capacity display light to the transmissive display panel 5. It is possible to perform optical display of luminance. In addition, efficient heat dissipation is performed by increasing the conduction efficiency of heat generated from the LED, so that the transmissive display panel performs optical display in a stable state. In addition, since a special member for holding the heat pipe is eliminated, the heat dissipation device can be thinned, and the entire backlight device can be thinned.

  According to the image display device of the present embodiment, the backlight device can be thinned by eliminating a special member for holding the heat pipe 25, so that the entire image display device can be thinned. In addition, by setting the transmissive display panel to a substantially uniform temperature over the entire surface, it is possible to prevent color unevenness and the like and display stably. Further, according to the image display device according to the present embodiment, since the heat pipe 25 is held by the recess 9a provided in the back panel 9, a special member for holding the heat pipe 25 in the backlight device is unnecessary. Thus, the weight of the device is reduced and the device can be manufactured at a low cost.

FIG. 10 is an enlarged view of a part of the heat sink 26 shown in FIG.
Between the numerous fins 26e provided on the heat sink 26, a heat radiating groove 26d is formed. The direction of the groove 26d is formed so as to face the center portion of the second main surface 9e of the back panel 9, that is, the position where the control circuit package 31 and the like are provided. A protective cover 32 is provided on the second main surface 9e of the back panel.

  Moreover, the direction of the longitudinal direction of the recessed part 26b provided in the heat sink 26 is formed so that it may face the center part of the 2nd main surface 9e of a back panel. Thus, since the direction of the groove part 26d provided in the heat sink 26 and the direction of the longitudinal direction of the recessed part 26b for accommodating a heat pipe are formed in the same direction, resin is applied to the mold. When the heat sink 26 is manufactured by pouring, etc., the resin can be easily pushed out, and the work efficiency when manufacturing the heat sink is improved.

  Further, since the direction of the groove portion 26d of the heat sink 26 is directed to the position of the control circuit package 31 provided on the second main surface 9e of the back panel, the air 33 sent by the fan 27 provided on the heat sink 26 is provided. However, as shown in the figure, the control circuit package 31 and the like can be efficiently cooled because they go to the position where the control circuit package 31 and the like are provided through the groove 26d.

  Although the above-described embodiment has shown the transmissive liquid crystal display panel 1 for a display panel of a television receiver having a large display screen of 40 inches or more, the present invention is applied to various image display devices having a large screen. Is done.

FIG. 1 is an exploded perspective view of an essential part of a transmissive liquid crystal display panel shown as an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of an essential part of a transmissive liquid crystal display panel shown as an embodiment of the present invention. FIG. 3 is a plan view of a light emitting unit according to an embodiment of the present invention. FIG. 4 is an enlarged view of the vicinity of the end of the light emitting array in the light emitting unit shown in FIG. FIG. 5 is a cross-sectional view of main parts of the light emitting array and the heat sink cut along the YY line shown in FIG. FIG. 6 is a perspective view of a light emitting block used in an embodiment of the present invention. FIG. 7 is a diagram illustrating a state in which the light emitting block 11 is removed from the plan view of the light emitting unit 7 illustrated in FIG. 3. FIG. 8 is an enlarged view of an end portion in the longitudinal direction of the back panel in FIG. FIG. 9 is a perspective view of a main part on the back side of the image display apparatus shown as an embodiment of the present invention. FIG. 10 is an enlarged view of an end portion on the back side of the image display apparatus shown in FIG. FIG. 11 is a side view of an assembly of a light-emitting block body and a heat pipe used in a conventional image display device.

Explanation of symbols

  1 .... Transmission type liquid crystal display panel, 2 .... Liquid crystal panel unit, 3 .... Backlight unit, 4 .... Front frame member, 5 .... Liquid crystal panel, 6 .... Back frame member, 7 .... Light emitting unit, 9 ..Back panel, 9a ... Dent, 9b ... Hole, 9c ... Projection, 9d ... First main surface, 9e ... Second main surface, 10 .... Optical sheet block, 11 .... Light emitting block , 11A to F... Light emitting array, 12... Light emitting diode (LED), 13 .. Optical sheet laminate, 14 .. Diffuse light guide plate, 15 .. Diffuser plate, 16. Stud member, 18 ... Light-emitting block body, 19 ... Wiring board, 19a ... First main surface, 19c ... Second main surface, 20 ... Connector, 25 ... Heat pipe, 26 ... Heat sink, 26a ...・ Hem, 26b ・ ・Recessed portion, 26c .. projection, 26d .. groove, 26e .. fin, 27 .. fan, 31 .. substrate, 32 .. cover member, 33.

Claims (6)

A light emitting unit having a light emitting body mounted thereon;
A housing for mounting the light emitting unit;
A heat dissipating means for releasing heat;
A high heat transfer device for conducting heat from the light emitter to the heat radiating means, and
A heat dissipation device for a light emitting unit, wherein the housing is provided with a recess for accommodating the high heat transfer device. The heat radiating device for a light emitting unit according to claim 1, wherein the heat radiating means is provided with a recess for accommodating the high heat transfer device. The light emitting unit according to claim 2, wherein the direction along the longitudinal direction of the recess provided in the heat radiating means and the direction of the heat radiating groove provided in the heat radiating means are the same direction. Heat dissipation device. The heat radiating device for a light emitting unit according to claim 1, wherein the housing is provided with a fitting portion for fitting the heat radiating means. In a backlight device that supplies display light from the back side of this display panel in combination with a transmissive display panel,
A light emitting unit in which a large number of light emitting diodes are mounted on a wiring board;
A back panel for mounting the light emitting unit;
A heat dissipating means for releasing heat;
A high heat transfer device for conducting heat from the light emitter to the heat radiating means, and
A backlight device, wherein the back panel is provided with a recess for accommodating the high heat transfer device. A transmissive display panel;
A light emitting unit in which a large number of light emitting diodes are mounted on a wiring board;
A back panel for mounting the light emitting unit;
A heat dissipating means for releasing heat;
In an image display device comprising: a high heat transfer device for conducting heat from the light emitting diode group to the heat radiating means;
An image display device, wherein the back panel is provided with a recess for accommodating the high heat transfer device.

Images