JP2005316337A - Backlight device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To uniformize temperature distribution over the entire surface of a backlight device, and to reduce the thickness thereof, by efficiently radiating heat produced from a number of light-emitting diodes (LEDs). <P>SOLUTION: The backlight device is equipped with a radiator plate 24 which fixes a wiring substrate 19 with the LEDs 12 mounted thereon and which is attached to a back panel 9, a heat pipe 25 which is attached to the radiator plate 24, a heat sink 26 which is disposed on the side part of the back panel 9 and to which heat produced from the LEDs 12 is conducted with the back panel 9 and the heat pipe 25 and cooling fans 27 attached to the heat sink 26. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a backlight device that supplies display light emitted from a plurality of light emitting diodes to a transmissive display panel such as a transmissive liquid crystal display (LCD), and in particular, is generated from a group of light emitting diodes. The present invention relates to a backlight device including a heat dissipation unit that efficiently dissipates heat.

  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. To do.

  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. For 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 the primary light source. Alternatively, there is a problem of solving problems such as uniformity due to 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. Even in such area light type backlight devices, there is a demand for solving the problems of the above-mentioned cold cathode fluorescent lamps, and particularly in large television receivers exceeding 40 inches, there are problems of high brightness and high uniformity. Has become more prominent.

  On the other hand, in the area light type backlight device, in place of the cold cathode fluorescent lamp described above, white light is obtained by two-dimensionally arranging a large number of red, green and blue light emitting diodes (LEDs) on the back side of the diffusion film. An LED area light type backlight that obtains the attention is attracting attention. Such an LED backlight device is designed to reduce the cost as the cost of the LED is reduced and to display a high luminance on a large liquid crystal panel with low power consumption.

  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 formed on the back surface of the liquid crystal panel, the heat generated as described above is stored in the sealed space portion to increase the temperature of the display device. 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. . The LED backlight device has a problem that operation becomes unstable due to the influence of heat on electronic components, integrated circuit elements, and the like due to high temperatures.

  Therefore, in the LED backlight device, appropriate heat radiating means for radiating the heat generated from the LED is provided. In the LED backlight device, for example, it is considered that the cooling air is sent by a cooling fan to dissipate the generated heat. However, since vibration and blurring occur, the space part provided with the diffusion film and the reflection film It is not possible to adopt a configuration in which cooling air is directly blown on the slab.

  Therefore, the LED backlight device employs a heat dissipation structure that conducts heat by guiding generated heat from a sealed space portion to a heat sink formed of, for example, an aluminum material by a heat conductive member. In the LED backlight device, since the heat conducting member shields the display light, it cannot be arranged directly in the sealed space, heat can be radiated efficiently and uniformly in the sealed space, and the heat sink can be as short as possible. Conditions such as coupling and efficient heat dissipation are required, and the structure is complicated to realize these conditions. Further, in the LED backlight device, a phenomenon such as color unevenness occurs when the liquid crystal panel does not have a uniform temperature distribution over the entire surface.

  In an LED backlight device, for example, by efficiently attaching a heat sink to a wiring board on which a large number of LEDs are mounted or a back plate that supports the wiring board, efficient heat dissipation is performed. However, in the LED backlight device, a circuit package or the like for driving each LED or performing lighting control is attached to the back plate. In the LED backlight device, in order to stably operate these circuit packages, when the heat sink, which is a large component, is directly attached to the above-described part, the thickness of the device increases and the thinning effect using the liquid crystal display panel is achieved. Cannot be fully exerted.

  In the LED backlight device, for example, it is necessary to provide an appropriate bracket member or the like which is interposed between the back plate and constitutes a heat insulating member and is isolated from the heat sink. In the LED backlight device, there arises a problem that the thickness is increased and the efficiency of assembly and the like is lowered.

  In the LED backlight device, for example, it is considered that the heat sink is disposed in a side part away from the mounting area of the circuit package or the like. There is a problem that is not fully exhibited. In the LED backlight device, it is possible to increase the heat dissipation effect by combining a cooling fan with a heat sink, but the thickness is further increased by the combination of cooling fans. In the LED backlight device, a so-called muffler type cooling fan that generates a small amount of noise is used for the cooling fan.

  Therefore, the present invention aims to increase the brightness of the display panel by providing a large number of light emitting diodes, and to keep the thickness thin and efficiently dissipate heat generated from the light emitting diode groups. An object is to provide an apparatus.

  The backlight device according to the present invention that achieves the above-mentioned object is combined with a transmissive display panel and supplies display light emitted from the light emitting diode group from the back side to the display panel, thereby causing images and the like to have high luminance. To be displayed. The backlight device includes a heat radiating unit so that heat generated from the light emitting diode group is efficiently radiated. In the backlight device, the heat radiating unit is opposed to the side of the back panel, the heat radiating plate that fixes the wiring board and is attached to the back panel, the heat pipe that is attached to the heat pipe fitting formed on the heat radiating plate, and the side of the back panel. And a heat sink that is integrally formed with a plurality of fins that are thermally conducted from the heat radiating plate and the heat pipe, and a cooling fan that is assembled to the heat sink and allows cooling air to flow between the fins.

  In the backlight device configured as described above, a large number of light-emitting diode groups are turned on to supply high-capacity display light to the transmissive display panel, thereby displaying a high-luminance image or the like. To be done. In the backlight device, a large amount of heat generated in the space between the backlight unit and the transmissive display panel generated by the lighting operation of each light emitting diode is efficiently radiated by the radiating unit, so that the transmissive type High brightness image display is performed with the display panel being in a stable state. In the backlight device, the transmissive display panel is brought to a substantially uniform temperature over the entire surface by the heat radiating unit, so that the occurrence of color unevenness or the like can be prevented or stable operation of each part can be performed.

  In the backlight device, generated heat is conducted from the wiring board to a heat radiating plate formed of a metal material having a good thermal conductivity such as an aluminum material. In the backlight device, the heat radiating plate absorbs heat from the wiring board and efficiently transmits the heat to the heat sink by the heat radiating plate and a heat pipe having a high efficiency of heat conduction. In the backlight device, a heat sink assembled with a cooling fan efficiently dissipates the heat generated by each heat-transmitted light emitting diode. The backlight device includes a relatively large heat sink and cooling fan. However, the backlight device can be reduced in thickness by arranging these on the side portions and conducting heat with a highly efficient heat conducting member.

  As described in detail above, in the backlight device according to the present invention, the backlight unit having a large number of light emitting diode groups as light sources supplies high-capacity display light to the transmissive display panel. Allows optical display of luminance to be performed. In the backlight device, heat generated by each light-emitting diode is turned on and becomes a large capacity in the space between the backlight unit and the transmissive display panel to the heat sink by the heat radiating plate and the heat pipe. In addition, the heat sink is cooled by a cooling fan so that efficient heat dissipation is performed and an image or the like is displayed in a stable state of the transmissive display panel. In the backlight device, it is possible to reduce the thickness of the heat radiating unit having a high capability of heat radiating characteristics, thereby reducing the overall thickness. In the backlight device, by setting the transmissive display panel to a substantially uniform temperature over the entire surface, it is possible to display a stable image or the like in which occurrence of color unevenness is prevented.

  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 an outer peripheral edge portion of the liquid crystal panel 5 sandwiched between the front frame member 4 via spacers 2 </ b> A, 2 </ b> B, guide members 2 </ b> C, and the like. And a frame-like back frame member 6 held by

  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.

  The liquid crystal panel 5 has a polyimide alignment film in which liquid crystal molecules are horizontally aligned at the interface, and the deflection film and the retardation film achromatic and white the wavelength characteristics 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, Of course, it may be a liquid crystal panel provided with the various structure provided conventionally.

  The backlight unit 3 is arranged on the back side of the liquid crystal panel unit 2 described above, and supplies a display light, a light emitting unit 8 that radiates heat generated in the light emitting unit 7, and the light emitting units 7. And the heat dissipating unit 8 and a back panel 9 which is combined with the front frame member 4 and the back frame member 6 and constitutes a mounting member for the housing 33 (see FIG. 14). The backlight unit 3 has an outer dimension that is opposed to the entire back 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.

  In the backlight unit 3, the light emitting unit 7 includes an optical sheet block 10 and a light emitting block 11 having a large number of light emitting diodes (hereinafter referred to as LEDs) 12. The optical sheet block 10 is installed opposite to the back side of the liquid crystal panel 5, and details thereof are omitted. It is comprised from the sheet | seat laminated body 13, the diffusion light guide plate 14, the diffusion plate 15, the reflection sheet 16, etc. 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 11 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 9a of the back panel 9 via the bracket member 14A.

  In the optical sheet block 10, the diffusion plate 15 and the reflection sheet 16 are attached to the back panel 9 by holding the opposing distance between the diffusion plate 15 and the above-described diffusion light guide plate 14 by a plurality of optical stud members 17. . 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. On the diffusion plate 15, a large number of light control dots 15 a are formed so as to be opposed to the large number of LEDs 12 of the light emitting blocks 11 that are arrayed 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.

  The optical sheet block 10 is configured so that the display light emitted from each LED 12 is radiated to the surroundings as described above so that the light is directly incident on the diffusion light guide plate 14 and does not partially increase in luminance. ing. 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.

  When a part of the display light emitted from each LED 12 is incident on the diffusion plate 15 beyond the critical angle, the optical sheet block 10 is reflected on the surface of the diffusion plate 15. 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 repeatedly reflecting, 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 integrally formed of milky white synthetic resin material having light guide property, mechanical rigidity, and a certain degree of elasticity such as polycarbonate resin, for example, as shown in FIG. 2 and FIG. 9 is attached to a mounting portion 9a formed integrally with 9, respectively.

  The back panel 9 is formed with a large number of attachment portions 9b that are formed integrally with a substantially trapezoidal convex portion on the inner surface side. In the back panel 9, the upper surface of the mounting portion 9 b constitutes the placement surface of the diffusion plate 15, and each mounting hole 9 c is provided through the back panel 9. In the optical sheet block 10, the diffusion plate 15 and the reflection sheet 16 are positioned and combined on the first main surface 9 d with respect to the back panel 9 via the optical stud members 17. A large number of attachment holes 15b and 16a are formed in the diffusion plate 15 and the reflection sheet 16 corresponding to the attachment holes 9c provided in the attachment portions 9b on the back panel 9 side.

  As shown in FIG. 5, each optical stud member 17 includes a shaft-shaped base portion 17a, a mounting portion 17b formed at the tip of the shaft-shaped base portion 17a, and a predetermined distance from the mounting portion 17b. A flange-shaped first receiving plate portion 17c integrally formed around the circumference of the shaft-shaped base portion 17a, and integrally formed around the circumference of the shaft-shaped base portion 17a with a predetermined interval from the first receiving plate portion 17c. And a flange-shaped second receiving plate portion 17d. Each optical stud member 17 is formed with an axial length in which the shaft-like base portion 17a defines the facing distance between the attachment portion 9b of the back panel 9 and the diffusion light guide plate 14, and a predetermined length from the second receiving plate portion 17d. A step portion 17e is formed at the height position.

  Each optical stud member 17 is formed such that the shaft-like base portion 17a has a long-axis conical shape in which the stepped portion 17e has a larger diameter than the mounting hole 15b of the diffusion plate 15 and gradually becomes smaller in diameter toward the tip portion. Has been. Each optical stud member 17 is formed with an axial stealing hole 17f in the axial base portion 17a located slightly above the stepped portion 17e. The meat stealing hole 17f is formed in the shaft base 17a in a range of a portion whose outer diameter is larger than that of the mounting hole 15b of the diffusion plate 15, and imparts convergence to this portion.

  Each optical stud member 17 is formed with an interval at which the first receiving plate portion 17 c and the second receiving plate portion 17 d maintain the facing interval between the diffusion plate 15 and the reflection sheet 16. Each optical stud member 17 has a shaft-like base portion 17a formed so that the first receiving plate portion 17c and the second receiving plate portion 17d have substantially the same diameter as the mounting hole 15b of the diffusion plate 15. Each optical stud member 17 has a mounting portion 17b whose outer diameter is substantially equal to the outer diameter of the mounting hole 9c on the back panel 9 side and is gradually larger than the mounting hole 9c in the axial direction. It has an arrowhead shape. Each optical stud member 17 is given converging habits when the mounting portion 17b forms a slit 17g from the large diameter portion toward the distal end side.

  Each optical stud member 17 has a mounting portion 17 a formed so that the distance between the large diameter portion and the first receiving plate portion 17 b is substantially equal to the thickness of the back panel 9 and the thickness of the diffusion plate 15. In each optical stud member 17, the first receiving plate portion 17 b has a larger diameter than the mounting hole 15 b of the diffusion plate 15, and the second receiving plate portion 17 d has a larger diameter than the mounting hole 16 a of the reflection sheet 16. Has been formed.

  In the optical sheet block 10, the reflection sheet 16 is combined on the mounting portion 9b of the back panel 9 with the mounting holes 9c and the mounting holes 16a facing each other. In the optical sheet block 10, each optical stud member 17 is pushed into the attachment portion 17 b from the first main surface 9 d side of the back panel 9 from the attachment hole 16 a side of the reflection sheet 16. In the optical sheet block 10, the mounting portion 17 b converges by the action of the slit 17 g and returns to the natural state after passing through the mounting hole 9 c on the back panel 9 side, whereby each optical stud member 17 is prevented from coming off. It is assembled in a standing state on the mounting portion 9b.

  In the optical sheet block 10, as shown in FIG. 5, each optical stud member 17 sandwiches the mounting portion 9b and the reflection sheet 16 in the thickness direction between the mounting portion 17b and the first receiving plate portion 17c. The reflective sheet 16 is held in a state of being positioned with respect to the back panel 9. In the optical sheet block 10, each optical stud member 17 is erected on the mounting portion 9 b of the back panel 9 with the upper portion protruding from the reflection sheet 16 from the first receiving plate portion 17 c of the axial base portion 17 a. The

  In the optical sheet block 10, the diffusion plate 15 is combined with each optical stud member 17 by fitting each mounting hole 15 b into the opposite tip portion 17 h. In the optical sheet block 10, each optical stud member 17 converges the large diameter portion by the action of the meat stealing hole 17 f so that the diffusion plate 15 is pushed in the axial direction. In the optical sheet block 10, the diffusion plate 15 gets over the stepped portion 17e and hits the second receiving plate portion 17d with respect to each optical stud member 17, and between the stepped portion 17e and the second receiving plate portion 17d. It is pinched.

  In the optical sheet block 10, as shown in FIGS. 4 and 5, each optical stud member 17 projects an upper portion from the second receiving plate portion 17 d of the axial base portion 17 a from the diffusion plate 15. In the optical sheet block 10, the diffusion light guide plate 14 in which the optical sheet laminate 13 is overlapped is assembled to the tip end portion 17 h of each optical stud member 17 so that the bottom surface side thereof is abutted.

  In the optical sheet block 10 configured as described above, a large number of optical stud members 17 respectively assembled on the first main surface 9d of the back panel 9 by a simple method of pushing the mounting portion 17b into the mounting hole 9c. The diffusion plate 15 and the reflection sheet 16 are positioned, and the function of accurately maintaining the facing distance between the diffusion plate 15, the reflection sheet 16, the diffusion light guide plate 14, and the optical sheet laminate 13 is achieved. The optical sheet block 10 includes the plurality of optical stud members 17 described above, thereby eliminating the need for complicated positioning structures and spacing structures, and simplifying the assembly process. Each optical stud member 17 can be used interchangeably with liquid crystal panels 5 of various sizes, and parts can be shared.

  In addition, about the optical stud member 17, it is not limited to the structure mentioned above, Based on the structure of the optical sheet block 10, the specific structure of each part is changed suitably. The optical stud member 17 is attached by being pushed into the attachment hole 9c of the back panel 9 by, for example, forming the slit 17g of the attachment portion 17b and imparting convergence habitability. The convex portion may be formed integrally and fitted into the mounting hole 9c having a key groove on the inner peripheral portion, and then rotated to be prevented from coming off.

  In the optical sheet block 10, each member is accurately positioned to guide display light in a stable state in the light guide space H formed between the diffusion light guide plate 14 and the reflection sheet 16. Since the operations such as diffusion and reflection are performed, the occurrence of uneven color in the liquid crystal panel 5 is suppressed. In the optical sheet block 10, each optical stud member 17 provided in the light guide space portion H is formed of milky white light guide synthetic resin material, diffuses display light incident on the inside from its outer peripheral surface, and a tip portion 17h is formed. The display light is uniformly incident on the diffusing light guide plate 14 from the light guide space H by preventing the light from being partially illuminated.

  By the way, in the optical sheet block 10, as shown in FIG. 3, the optical stud member 17 described above is provided with five in the horizontal direction and three in the vertical direction, for a total of fifteen. LED12 is arrange | positioned and located between each row | line | column of the light emission block 11 mentioned later which has arrange | positioned 6 rows in the horizontal direction. Further, in the optical sheet block 10, the diffusion plate 15 and the reflection sheet 16 described above have different characteristics on the front and back surfaces, and must be combined without making a mistake.

  As described above, the diffusion plate 15 and the reflection sheet 16 are provided with mounting holes 15b and 16a through which the shaft-like base portion 17a of the optical stud member 17 passes. A total of 15 attachment holes 15 b and 16 a are formed in the diffusion plate 15 and the reflection sheet 16, corresponding to each optical stud member 17, five in the horizontal direction and three in the vertical direction. In the optical sheet block 10, as shown in FIG. 3, the second optical stud member 17A from the left side of the lower row is placed on the back panel 9 at a different position from the second optical stud members 17 on the upper row side. Stand up. In the optical sheet block 10, the second mounting holes 15 b and 16 a from the left side of the lower row facing the optical stud member 17 </ b> A are placed on the diffusion plate 15 and the reflection sheet 16 at different positions from the mounting holes 15 b and 16 a of the upper row. Form.

  Therefore, in the optical sheet block 10, even if the diffusion plate 15 and the reflection sheet 16 have the wrong front and back surfaces, the mounting holes 15b and 16a do not exist at positions facing the optical stud member 17A so that they cannot be combined. Thus, an incorrect combination prevention structure is configured. In the optical sheet block 10, the mounting holes 15b and 16a of the optical stud member 17A, the diffusing plate 15 and the reflecting sheet 16 constituting the erroneous combination preventing structure may be provided at any position other than the center position. Since they are combined in a stable state, it is better to provide them at the inner position than at the outer peripheral position, and they may be provided at a plurality of places instead of one place.

  In the backlight unit 3, since the light emitting unit 7 includes 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. So that As shown in FIG. 3, the light emitting block 11 includes six rows 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. The light emitting unit 11 includes three light emitting block bodies (18A to 18C) A to (18A to 18C) F, which will be described in detail later, in which each light emitting array 11A to 11F is arranged in the length direction. Thus, a total of 18 light emitting block bodies 18 are provided. 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 FIGS. 4 and 6, each light emitting block 18 includes a plurality of red LEDs, green LEDs, blue LEDs (referred to collectively as LEDs 12), and these LEDs 12 on the first main surface 19 a in the longitudinal direction. And a horizontally-long rectangular wiring board 19 mounted in a predetermined order. Each light emitting block 18 has a total of 25 LEDs 12 mounted on each wiring board 19 by combining an appropriate number of red LEDs, green LEDs, and blue LEDs. Accordingly, the light-emitting block 11 includes 75 LEDs 12 for a total of 450 LEDs 12 for each of the light-emitting arrays 11A to 11F. 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 near one side 19b in the width direction of the first main surface 19a and on both sides in the longitudinal direction, and the first connector 20A on the signal output side and the signal The second connector 20B on the input side is mounted. 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.

  As shown in FIG. 3, the light-emitting block 11 has three light-emitting block bodies 18AA to 18AC in the length direction, with each wiring board 19 facing one side 19b downward and the light-emitting array 11A in the first row. Arranged side by side. In the light emitting block 11, three light emitting block bodies 18BA to 18BC are arranged in the length direction in the light emitting array 11B in the second row, with each wiring board 19 having one side portion 19b facing the light emitting array 11A. Arranged in In the light emitting block 11, the light emitting blocks 11C to 11F are similarly arranged in such a manner that three light emitting block bodies 18 are arranged in the length direction by alternately changing the direction of the wiring board 19 with respect to each other.

  In the light emitting block 11, each second connector 20B of the light emitting block bodies 18AC to 18FC arranged on the right side of each column light emitting array 11A to 11F constitutes a signal input unit that drives each LED 12 in each column. In the light emitting block 11, as shown in FIG. 4, one first connector 20A and the other second connector 20B of the light emitting block bodies 18 arranged adjacent to each other are adjacent to each other. The light emitting block 11 connects the first connector 20A and the other second connector 20B with a lead wire with a connector (not shown) so that the shortest wiring is performed. The light emitting block 11 draws out signal output lead wires 21 with connectors from the light emitting block bodies 18AA to 18FA arranged on the left side for each of the light emitting arrays 11A to 11F, and these lead wires 21 are as shown in FIG. The light emitting arrays 11A to 11F are guided between the light emitting arrays 11A to 11F and bundled with the clampers 22 provided to the light emitting arrays 11A to 11F.

  Although not shown, the light emitting block 11 has signal input lead wires with connectors connected to the light emitting block bodies 18AC to 18FC arranged on the right side for each of the light emitting arrays 11A to 11F. Each signal input lead wire is drawn from the second main surface 9e side of the back panel 9 through the drawing opening 23, and is bundled with a clamper 22 provided between the light emitting arrays 11A to 11F and the light emitting block bodies 18AC to 18FC. Connected. The light emitting block 11 includes a pair of light emitting blocks (11A, 11B), (11C, 11D), and (11E, 11F) that are paired with the first connector 20A and the second connector 20A provided on the wiring board 19, respectively. The connectors 20B are arranged to face each other.

  In the light emitting block 11, as described above, the holding of the signal input / output lead 21 using the space between the light emitting arrays 11A to 11F and the provision of the guide structure can improve the efficiency of the space and simplify the wiring process. Figured. In the light-emitting block 11, the position of the first connector 20A and the second connector 20B prevents each wiring board 19 from being mistakenly assembled, simplifies the wiring structure between the wiring boards 19, the wiring process, and the lead wires. Sharing will be achieved. In the light emitting block 11, the lead wires 21 are easily routed to the second main surface 9e side of the back panel 9. In the light emitting block 11, since the lead wire for signal input and the lead wire for signal output are guided by being bundled by the clamper 22, these lead wires cooperate to suppress noise.

  In the light emitting block body 18, a red LED, a green LED, and a blue LED, which are combined in an appropriate number as described above, are arranged on the first main surface 19 a of the wiring board 19 on the same axis line in this order. Twenty-five LEDs 12 are mounted. As for each LED12, as shown in FIG. 7, the light emitting element 12a is hold | maintained at the resin holder 12b, and the terminal 12c is pulled out from the resin holder 12b.

  In the light emitting block 11, the LEDs 12 of the light emitting block body 18 are turned on to generate heat as the display light is emitted. Since the light emitting unit 7 forms the light guide space H whose periphery is sealed by combining the light emitting block 11 on the back side of the optical sheet block 10 as described above, the heat generated from each of the plurality of LEDs 12 is large. The amount of heat becomes so large that the light guide space H is trapped in a high temperature state. The light emitting unit 7 changes the characteristics of the optical sheet bodies described above of the optical sheet block 10 due to the increase in temperature, causes the lighting state of the LEDs 12 to become unstable, and causes color unevenness in the liquid crystal panel 5. Problems such as destabilizing the operation of the electronic components and the like constituting the device occur.

  In the backlight unit 3, the occurrence of the above-described problem is suppressed by efficiently radiating the heat generated from each LED 12 by the light emitting unit 7 by the heat radiating unit 8. The heat dissipating unit 8 is provided for each of the light emitting arrays 11A to 11F described above, and has six heat dissipating plates 24A to 24F (hereinafter collectively referred to as heat dissipating plates 24) that also serve as mounting members for the light emitting block body 18, and these heat dissipating units. Six heat pipes 25A to 25F (hereinafter collectively referred to as heat pipes 25) attached to the plate 24, and a pair of left and right heat sinks 26A and 26B (hereinafter referred to as heat sinks) to which both ends of the heat pipes 25 are connected. 26), and a cooling fan 27 for promoting the cooling function of the heat sink 26. The heat radiating unit 8 forms an efficient heat conduction path for the heat sink 26 by assembling a heat pipe 25 integrally with each heat radiating plate 24 as will be described in detail later.

  Each of the heat radiating plates 24 is made of an aluminum material having excellent thermal conductivity, good workability, light weight, and low cost, and has a long length substantially equal to the length and width of each of the light emitting arrays 11A to 11F described above by extrusion. It is formed in a rectangular plate shape. Each heat dissipating plate 24 also serves as an attachment member for the light emitting block body 18 and thus is formed with a predetermined thickness having mechanical rigidity. Note that each heat radiating plate 24 is not limited to an aluminum material, and may be formed of, for example, an aluminum alloy material, a magnesium alloy material, a silver alloy material, or a copper material having good thermal conductivity. When each heat dissipation plate 24 is relatively small, it is formed by an appropriate processing method such as pressing or cutting.

  As shown in FIGS. 6 and 7A, each wiring board 19 of the light-emitting block body 18 abuts the end face in the length direction of each heat radiating plate 24 with the first main surface 24a as an overlapping surface. Combined by state. Each heat radiating plate 24 is formed with a board fitting recess 24b in which the wiring board 19 is fitted to the first main surface 24a over the entire length. Each heat dissipating plate 24 has a board fitting recess 24b having substantially the same width as the wiring board 19 and a height substantially equal to the thickness thereof, and the second main surface 19c of the wiring board 19 in the width direction. Hold both sides and combine. Each heat dissipating plate 24 fixes the wiring board 19 combined with the board fitting recess 24 b onto the first main surface 24 a by a plurality of mounting screws 28.

  In each of the heat radiating plates 24, the receiving surface portion 24 c in the length direction in which the second main surface 19 c of the wiring substrate 19 is in close contact with each other by leaving the central region in the width direction as a convex portion having a predetermined width in the board fitting recess 24 b. And the meat stealing recesses 24d and 24e are formed on both sides of the receiving surface 24c over the entire length in the length direction. As shown in FIG. 7A, each heat radiating plate 24 is formed with a width corresponding to the LED mounting area 19d on which each LED 12 of the wiring board 19 is mounted, as shown in FIG. 7A. The heat is efficiently transmitted from the LED mounting region 19d that is heated and heated most by the operation, so that heat is radiated. In addition, although each heat sink plate 24 formed the meat stealing recessed part 24d and 24e in order to maintain weight reduction and dimensional accuracy, these meat stealing recessed parts 24d and 24e may also be comprised as a heat pipe fitting part. .

  Each heat radiating plate 24 is formed with a heat pipe fitting recess 24g into which the heat pipe 25 is fitted on the second main surface 24f side facing the first main surface 24a. Each heat dissipating plate 24 is integrally formed with a plurality of mounting stud portions 24h and positioning dowels 24i that constitute a mounting portion with the back panel 9 at an appropriate position on the second main surface 24f. The heat pipe fitting recess 24g is a groove having a substantially arch-shaped cross section formed over the entire region in the length direction at a substantially central portion in the width direction facing the receiving surface portion 24c. As will be described later, the heat pipe fitting recess 24g is formed with an opening shape that allows the heat pipe 25 fitted therein to be temporarily held without a holding member or the like. The heat pipe fitting recess 24g has an opening width substantially equal to the outer diameter of the heat pipe 25, and is formed with a slightly small height (depth).

  In the heat dissipating unit 8, the heat pipe fitting recess 24g is formed over the entire length in the length direction on the second main surface 24f side of the heat dissipating plate 24 and one heat pipe 25 is attached. In order to improve the heat dissipation capability, for example, two or more heat pipes 25 may be attached to each heat dissipation plate 24. Since each heat pipe 25 interferes with each other and the heat conduction ability may be lowered by attaching to each heat radiation plate 24 at the same location, one heat pipe 25 is attached to each second main surface 24f. Two or more heat pipe fitting recesses 24g parallel to each other are preferably formed adjacent to each other.

  In the heat radiating unit 8, for example, when two or more heat pipes 25 are attached to the heat radiating plate 24, the heat radiating unit 24 has the same diameter due to the characteristic of the heat pipe 25 that does not change much in the heat conduction ability due to the difference in outer diameter. Use it. With this measure, the heat pipe 25 can share parts, prevent assembly errors, and the like.

  In the heat radiating unit 8, one heat pipe 25 is attached to a heat pipe fitting recess 24 g formed in each heat radiating plate 24. In the heat radiating unit 8, due to the configuration of the transmissive liquid crystal display panel 1, for example, it may be necessary to form a mounting portion such as a part in the middle of the heat pipe fitting recess 24 g, Since it cannot arrange | position, the heat pipe 25 becomes long, and the heat conductive capability of a front-end | tip part may fall. In the heat radiating unit 8, two short heat pipes 25 may be fitted from the left and right sides in the heat pipe fitting recess 24g.

  As described above, the heat radiating unit 8 is formed with the heat pipe fitting recess 24g in each heat radiating plate 24, and the heat pipe 25 is assembled therein. It is arranged at a position closer to the mounting area 19d. The heat dissipating unit 8 uses each heat dissipating plate 24 having a predetermined thickness, and a heat pipe fitting recess 24g having an interval (thickness) between the apex portion and the receiving surface portion 24c of about 1 mm is formed on the heat dissipating plate 24, for example. As a result, the LEDs 12 mounted on the wiring board 19 having a thickness of about 1.7 mm to 1.8 mm and the heat pipes 25 are arranged to face each other at an interval of 2 mm or less, and efficient heat dissipation is performed. It becomes like this.

  In the heat radiating unit 8, each heat radiating plate 24 also serves as a holding member for the heat pipe 25 by attaching the heat pipe 25 in the heat pipe fitting recess 24g. The handling is simplified and the occurrence of bending or breakage is prevented. In the heat radiating unit 8, each heat radiating plate 24 is combined with the light emitting block body 18 and the heat pipe 25 positioned and close to each other. An efficient heat conduction path is formed between them. In the heat radiating unit 8, simplification of the attaching process of the heat pipe 25 to each heat radiating plate 24 is achieved.

  In the heat dissipating unit 8, each heat dissipating plate 24 is attached to the back panel 9 with the light emitting block body 18 being combined with the board fitting recess 24b and the heat pipe 25 being assembled within the heat pipe fitting recess 24g. It is precisely positioned and fixed via the part 24h and the positioning dowel 24i. Each of the heat radiating plates 24 may be fixed on the first main surface 9d of the back panel 9 by using an attachment screw 28 for fixing the wiring board 19.

  Each of the heat radiating plates 24 has a heat pipe fitting concave portion 24g having an arch-shaped concave portion that can be formed with high dimensional accuracy by extrusion, but is not limited to such a shape. The heat pipe fitting recess 24g may have any shape as long as the heat pipe 25 is fitted and held and adhesion to the outer periphery thereof is maintained. It is also possible to form in a shape.

  By the way, each heat radiating plate 24 presses the heat pipe 25 assembled in the heat pipe fitting recess 24g by the back panel 9 so as to adhere to the inner wall. For example, the dimensional accuracy of each part or the dimensional accuracy of the back panel 9 It is also considered that a gap is partially formed between the heat pipe 25 and the like and the heat conductivity is lowered. Therefore, in each heat radiating plate 24, as shown in FIG. 7B, for example, the heat pipe 25 may be caulked in the heat pipe fitting recess 24j by a caulking structure.

  Each heat dissipating plate 24 is formed so that the heat pipe fitting recess 24j has a depth substantially equal to the outer diameter of the heat pipe 25, and the heat pipe fitting recess 24j has a full length at the opposite opening edge. The caulking convex portions 24k and 24l are integrally formed. The caulking convex portions 24k and 24l may be formed at one opening edge portion of the heat pipe fitting concave portion 24j or may be partially formed. The caulking convex portions 24k and 24l may be provided in a staggered manner, for example, when they are partially formed at the opening edge portions facing each other.

  Each heat radiating plate 24 has the heat pipe fitting recess 24j assembled in the heat pipe fitting recess 24j with respect to the caulking projections 24k and 24l as shown by the chain line in FIG. 7B. Apply the caulking process to bend inward. In each heat radiation plate 24, the heat pipe 25 is pressed against the inner wall of the heat pipe fitting concave portion 24j by the caulking convex portions 24k and 24l and is brought into close contact therewith. Each heat dissipating plate 24 is more reliably integrated with the heat pipe 25, and the adhesion to the back panel 9 is also improved.

  In each of the heat dissipation plates 24, heat pipe fitting recesses 24g and 24j opened in the second main surface 24f are formed and the heat pipe 25 is attached from the second main surface 24f side. It is not limited. In each heat radiating plate 24, a heat pipe fitting hole opened at at least one end in the longitudinal direction may be formed so that the heat pipe 25 is assembled therein. Moreover, in each heat radiating plate 24, you may make it form the heat pipe fitting recessed part opened to the end surface of the width direction.

  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 made of a metal pipe such as copper 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 material is exhausted, and has a highly efficient heat conduction capability. As described above, the heat pipe 25 is integrally assembled with each heat radiating plate 24, and both ends of each heat pipe 25 are connected to a heat sink 26 described later. In the heat pipe 25, the conduction medium enclosed inside receives heat conduction from the high-temperature side heat radiating plate 24 and vaporizes from liquid to gas. In the heat pipe 25, the vaporized conductive medium flows through the pipe to the connection portion with the low-temperature heat sink 26 and is cooled, thereby releasing condensation heat and liquefying. In the heat pipe 25, the liquefied conductive medium moves to the heat radiating plate 24 side by a capillary phenomenon through a plurality of longitudinal grooves or porous layers formed on the inner wall of the metal pipe, and circulates in the pipe. As a result, it has a highly efficient heat conduction effect.

  As described above, the heat pipe 25 is integrally mounted in the pipe fitting recess 24g of the heat radiating plate 24 so as to be provided for each of the light emitting arrays 11A to 11F and to face the light emitting block body 18. The heat pipe 25 is mounted in the pipe fitting recess 24g with a part of the outer peripheral portion protruding from the opening. As the heat pipe 25 is attached to the back panel 9 by attaching the heat radiating plate 24, the protruding portion is pressed into the pipe fitting recess 24g as shown by the arrow in FIG. It will be in close contact. As described above, the heat pipe 25 does not require a holding member with respect to the heat radiating plate 24, and is kept in close contact in the pipe fitting recess 24g. In general, the heat pipe 25 is combined by applying silicon grease or the like to the mounting portion in order to maintain adhesion with the heat radiating member. However, by adopting the above-described structure, such a countermeasure becomes unnecessary.

  The heat pipe 25 is more reliably integrated with the heat radiating plate 24 by adopting the above-described caulking structure shown in FIG. Become.

  In the heat radiating unit 8, the heat pipe 25 having a high efficiency of heat conduction is integrated and attached to the heat radiating plate 24 having the above-described configuration, so that the heat pipe 25 is close to the area immediately below the arrangement region of the LEDs 12 of the heat source. Thus, the configuration is extended. In the heat radiating unit 8, the wiring board 19 on which each LED 12 is mounted, the heat radiating plate 24 that holds the wiring board 19, and the heat pipe 25 are overlapped with each other to form a heat conductor to the heat sink 26. . In the heat radiating unit 8, space efficiency is achieved by such a configuration, and heat generated from each LED 12 is conducted to the heat sink 26 very efficiently to dissipate heat, thereby reducing the high temperature of the light guide space H and the backlight. The unit 3 supplies display light to the liquid crystal panel 5 with a stable operation.

  In the heat radiating unit 8, as shown in FIG. 8, the heat sinks 26 are respectively attached to the second main surface 9 e of the back panel 9 so as to be located on both sides in the length direction. These heat sinks 26 are also used alone or in combination with the heat pipe 25 as a heat radiating member such as a power source in various electronic devices. The heat sink 26 is a member having a large surface area by integrally forming a large number of fins from an aluminum material having excellent thermal conductivity. The heat sink 26 cools the high temperature part by receiving heat conduction from the high temperature part side and radiating heat from the surface of each fin.

  The larger the heat sink 26, the greater the heat dissipation effect, but the larger the thickness of the backlight unit 3 and the entire apparatus. The heat sink 26 is a large and heavy component. For example, when directly attached to a wiring board or the like, a heat conducting member interposed between a mounting bracket member or a high-temperature portion that retains insulation from a circuit component or a wiring pattern or the like. Etc., and the structure becomes complicated.

  In the heat dissipating unit 8, the large heat sink 26 that requires the above-described correspondence together with the plurality of heat dissipating plates 24 and the heat pipes 25 is skillfully arranged on the back panel 9, thereby suppressing the increase in size and the light emitting unit 7. The heat generated from the multiple LEDs 12 is efficiently radiated. In the heat radiating unit 8, the back panel 9 is not required to have a relief recess formed along the arrangement path of the heat pipe 25 due to the configuration of the heat radiating plate 24 and the heat pipe 25 described above. 9 can be formed in a flat shape as a whole. In the heat radiating unit 8, the flat portion is formed in the central region of the back panel 9 by attaching the heat sinks 26 to the left and right sides of the second main surface 9 e as described above with respect to the flat back panel 9. So that

  By the way, the back panel 9 is formed in an oblong rectangular plate shape having a size substantially equal to the outer shape of the liquid crystal panel 5 by using, for example, an aluminum material that is relatively light and has mechanical rigidity. Since the back panel 9 itself has thermal conductivity, the back panel 9 has an action of radiating heat generated from the light guide space H, circuit components, and the like. As described above, the back panel 9 is formed with the outer peripheral wall portion 9a combined with the front frame member 6 at the outer peripheral portion, and fixes a plurality of mounting portions 9b for mounting the optical stud member 17 and the heat radiating plate 24. A pull-out opening 23 or the like for drawing out the mounting hole or the lead wire 21 is formed. The back panel 9 is assembled by superimposing the heat radiating unit 8, the light emitting unit 7, and the liquid crystal panel 5 on the front surface, and further assembled to the mounting portion of the housing 33.

  The transmissive liquid crystal display panel 1 is provided with a control circuit package for driving the liquid crystal panel 5 and controlling the lighting operation of each LED 12 of the light emitting unit 7, and as shown in FIG. Also used as a mounting panel. The details of the control package are omitted, but the liquid crystal controller 29 that outputs a signal for controlling the operation to the liquid crystal panel 5 and the power control units 30A and 30B that control the power supply units of the liquid crystal panel 5 and the light emitting unit 7 are described. Or LED control units 31A and 31B for controlling the operation of the light emitting unit 7.

  In the transmissive liquid crystal display panel 1, a flat region is formed between the heat sinks 26A and 26B disposed on the left and right sides of the second main surface 9e of the back panel 9 as described above. Each control circuit package 29 to 31 is mounted. In the transmissive liquid crystal display panel 1, by mounting the control circuit packages 29 to 31 in a flat region, it is possible to attach the control circuit packages 29 to 31 firmly without causing a lift or the like by a simple process. In the liquid crystal display panel 1, since the control circuit packages 29 to 31 are thinner than the large heat sink 26 having a large thickness, the overall thinning is maintained.

  The control circuit packages 29 to 31 described above are mounted on a control board (not shown), and the control board is attached to the back panel 9. The control board is attached to the back panel 9 so as to be positioned between the heat sinks 26 arranged on both sides of the back panel 9 as described later.

  In the transmissive liquid crystal display panel 1, display light is supplied to the liquid crystal panel 5 using a large number of LEDs 12 provided in the light emitting unit 7 as a light source, as described above. The liquid crystal display panel 1 includes the heat dissipating unit 8 having the above-described configuration, so that heat generated from each LED 12 is efficiently conducted to the heat sink 26 by the heat dissipating plate 24 and the heat pipe 25 to be dissipated. This prevents a large amount of heat from being trapped in the light guide space H or the like. In the transmissive liquid crystal display panel 1, the characteristics of each optical sheet and the like are maintained, and the entire large screen of the liquid crystal panel 5 is maintained in a substantially uniform temperature distribution so as to display a uniform image without color unevenness. And the operations of the control circuit packages 29 to 31 are stabilized.

  9 and 10 show the results of measuring the heat dissipation characteristics of the first heat dissipating knit composed of a heat conducting member combined with a heat pipe and a heat sink, and the second heat dissipating knit composed of the heat conducting member and the heat sink. It is shown. In this measurement method, the temperature at the left and right end portions and the center portion with the passage of time was measured in a state where a 34 W applied DDC heat sink was divided from the center and only the right side was left. In the first heat dissipating knit, as shown in FIG. 9A, the overall temperature gradually increases with the passage of time, but the temperature difference of each part is stable within 1 ° C. Further, in the first heat dissipating knit, as shown in FIG. 5B, even in the left end portion where the heat sink does not exist, efficient heat conduction is performed to the heat sink by the action of the heat conducting member and the heat pipe. A substantially constant temperature distribution is maintained over the entire area.

  On the other hand, in the second heat radiating unit, as shown in FIG. 10A, the overall temperature gradually increases with time, and the right end portion where the heat sink is provided is restrained from rising due to its heat radiating action. The temperature difference between the right end and the left end gradually increases. In the second heat radiating unit, for example, the temperature distribution after 26 hours reaches a maximum of 7 ° C. at the right end and the left end as shown in FIG. Therefore, in the heat radiating unit, by combining the heat conducting member combined with the heat pipe and the heat sink, efficient heat conduction from the high temperature part to the heat sink is performed and heat radiation is performed. And uniform temperature distribution.

  As described above, the heat dissipating unit 7 is improved in heat dissipating efficiency by combining each heat sink 26 with the cooling fan 27. Each heat sink 26 blows air between the fins by the cooling fan 27, thereby promoting heat dissipation from the surface of each fin. In the heat dissipation unit 7, a pair of cooling fans (27A, 27B) and (27C, 27D) are attached to the heat sinks 26, respectively. The cooling fan 27 is also commonly used as a cooling and heat dissipating device by attaching it to a housing or the like in various electronic devices or the like. Each heat sink 26 is configured so that the fins are closed by, for example, a back cover of the housing, etc., except for the mounting portion of the cooling fan 27, so that the cooling air flow path is held.

  As shown in FIG. 12, the cooling fan 27 is rotated by a square frame casing 27a, a motor section 27c disposed at the center of the casing 27a via a plurality of arm sections 27b, and the motor section 27c. And the fan 27d. In the cooling fan 27, attachment portions 27e are formed at the four corners of the housing 27a, and openings 27f penetrating in the thickness direction are formed between the arm portions 27b. The cooling fan 27 is attached with the opening 27f facing the opening 33a formed in the back cover of the housing 33 as shown in FIG. The cooling fan 27 rotates when the motor unit 27c is powered on, and the fan 27d draws air from one side of the opening 27f and exhausts air from the other side. That is, the cooling fan 27 is a so-called vertical cooling fan.

  The cooling fan 27 is attached to the back surface portion of the heat sink 26 by screwing the attachment portion 27e on the attachment portions 26a and 26a having a large width, and is cooled by sending air between the fins through the opening portion 27f. . As shown in FIG. 11, the cooling fan 27 is mounted at a substantially central portion in the length direction of the heat sink 26 to uniformly cool the heat sink 26 in the vertical direction.

  By the way, in the cooling fan 27, when each side of the casing 27a is mounted in a parallel state with respect to the direction of the fins as shown in FIG. 12B, an opening is formed by the mounting portions 26b and 26b on the heat sink 26 side. A part of 27f is blocked, the amount of air blown between the fins is reduced, and the cooling efficiency is lowered. Therefore, the cooling fan 27 is fixed in a state where each side of the casing 27a is inclined by 90 degrees with respect to the fin direction as shown in FIG. The heat sink 26 is efficiently cooled by performing more air flow.

  As described above, the heat radiating unit 7 is thinned by mounting the control circuit packages 29 to 31 in a flat region formed between the heat sinks 26. When each cooling fan 27 is attached to the back surface of the heat sink 26, the heat radiating unit 7 protrudes to the back side, so that the effect of the above-described reduction in thickness can be sufficiently exerted. .

  Therefore, in the heat radiating unit 7, as shown in FIG. 13, the left and right heat sinks 26 may be constituted by an upper heat sink 26A1, a lower heat sink 26A2, and an upper heat sink 26B1 and a lower heat sink 26B2, respectively. In the heat dissipating unit 7, the upper heat sinks 26A1, 26B1 and the lower heat sinks 26A2, B2 each hold a space sufficient to dispose the cooling fan 32 at a substantially central position in the height direction so as to face each other. 9 is attached.

  Two cooling fans 32 are disposed between the upper heat sink 26A1 and the lower heat sink 26A2 on one side, respectively, and two units 32C are disposed between the upper heat sink 26B1 and the lower heat sink B2 on the other side. 32D is arranged. These cooling fans 32 have a basic configuration similar to that of the vertical cooling fan 27 described above, but a so-called horizontal cooling fan that has an opening formed on the outer peripheral side surface of the casing 27a and blows air in the outer peripheral direction. Used to be attached directly to the back panel 9. Therefore, in the heat radiating unit 7, the cooling fan 32 is disposed between the divided heat sinks as shown in FIG. The

  Note that the cooling fan 32 is not only used in a specification that sucks outside air and blows air between the fins of the heat sink 26 as described above. The cooling fan 32 may be used in a specification in which air is sucked out from between the fins of the heat sink 26 and exhausted to the outside by, for example, being inverted and attached.

  In the heat radiating unit 7, the pair of left and right heat sinks 26 are attached to the back panel 9 as described above. The heat sink 26 is integrally formed with a large number of small fins facing each other in parallel by an aluminum material, and has a characteristic shape when cut vertically. Therefore, in the liquid crystal display panel 1, as shown in FIG. 14, an opening 34 is formed in a part of the housing 33, and the end 26 c is exposed outward from the opening 34. It is attached to the back panel 9.

  The housing 33 is formed so that the opening 34 has an opening size substantially equal to the cross-sectional shape of the heat sink 26, and the front end of the heat sink 26 is fitted so as to form substantially the same surface as the outer surface. Therefore, in the liquid crystal display panel 1, the tip of the heat sink 26 exposed in the opening 34 forms part of the exterior body in cooperation with the housing 33, and forms a unique design from its unique shape and color. . In the liquid crystal display panel 1, a part of the heat sink 26 is directly exposed to the outside, so that the cooling efficiency can be improved.

  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 liquid crystal display devices having a large screen. Is done.

It is a principal part disassembled perspective view of the transmissive liquid crystal display panel shown as embodiment. It is a principal part longitudinal cross-sectional view of a transmissive liquid crystal display panel. It is a top view of a thermal radiation unit. It is a principal part perspective view of a light emission block. It is a principal part longitudinal cross-sectional view of the optical sheet block provided with the optical stud member. It is a perspective view of the assembly of a light emission block body and a thermal radiation plate. It is a side view of the assembly of a light emission block body and a thermal radiation plate. It is a principal part perspective view from the back side of a transmissive liquid crystal display panel. It is a heat dissipation characteristic figure of the heat dissipation unit which has a heat pipe and a heat sink. It is a thermal radiation characteristic figure of the thermal radiation unit which has a heat sink. It is a principal part perspective view from the back side of the transmissive liquid crystal display panel which combined the cooling fan with the heat sink. It is a principal part top view which shows the attachment structure of the cooling fan to a heat sink. It is a principal part perspective view from the back side of the transmissive liquid crystal display panel provided with the combined structure of another heat sink and a cooling fan. It is a principal part perspective view of the transmissive liquid crystal display panel using a heat sink as an exterior material.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Transmission type liquid crystal display panel, 2 Liquid crystal panel unit, 3 Backlight unit, 4 Full frame member, 5 Liquid crystal panel, 6 Back frame member, 7 Light emission unit, 8 Heat radiation unit, 9 Back panel, 10 Optical sheet block, 11 Light emission Block, 12 Light emitting diode (LED), 13 Optical sheet laminated body, 14 Diffusing light guide plate, 15 Diffusing plate, 16 Reflecting sheet, 17 Optical stud member, 18 Light emitting block body, 19 Wiring board, 20 Connector, 21 Lead wire, 22 Clamper, 23 Drawer opening, 24 Heat radiation plate, 25 Heat pipe, 26 Heat sink, 27 Cooling fan, 29 Liquid crystal controller, 30 Power supply control unit, 31 LED control unit, 32 Cooling fan, 33 Housing, 34 Opening

Claims (6)

In a backlight device that supplies display light to the display panel from a backlight unit that is combined on the back side of the transmissive display panel and has a plurality of light emitting diodes mounted on a wiring board.
A heat dissipation plate that fixes the wiring board and is attached to the back panel, a heat pipe that is attached to a heat pipe fitting formed on the heat dissipation plate, a heat sink that is attached to the back panel, and a cooling that cools the heat sink A heat dissipation unit having a fan,
A backlight device characterized in that heat generated from the light emitting diode group of the backlight unit is conducted to the heat sink through the heat radiating plate and the heat pipe to radiate heat.   The cooling fan is a vertical cooling fan having one main surface portion in the thickness direction as an air intake portion or an exhaust portion and the other main surface portion as an exhaust portion or an air intake portion, and is assembled to the back surface portion of the heat sink. The backlight device according to claim 1.   The cooling fan has fixing portions formed at four corners of a rectangular casing, and is fixed in a state where each side of the casing is inclined by approximately 90 degrees with respect to the heat sink. The backlight device according to claim 2. The heat sink is composed of a pair of upper and lower heat sinks that are attached to the side part of the back panel by providing a cooling fan attachment region between opposing ends with the fin direction as a height direction,
The horizontal cooling fan in which one main surface portion in the thickness direction is an intake portion or an exhaust portion and an orthogonal side surface portion is an exhaust portion or an intake portion is disposed in the cooling fan mounting region. The backlight device according to 1.   Each of the heat sinks forms a part of the exterior surface by facing the opening formed in the housing with the other end opposite to the end constituting the cooling fan mounting region facing substantially the same surface. The backlight device according to claim 4. The heat sinks are arranged opposite to each other on both sides in the longitudinal direction with respect to the back panel, and the circuit unit is mounted on the back panel with a region between the heat sinks as an attachment portion. The backlight device according to 1.

Images