JP2008251245A - Backlight device, and display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a backlight device with an inexpensive cost structure in which heat generated by a light-emitting diode is directly radiated from a heat radiation block thermally joined to a support base supporting the light-emitting diode without going through a lamp housing (installation base), thereby temperature increase and thermal distortion of the lamp housing are not caused. <P>SOLUTION: The backlight device has a light source in which a plurality of light-emitting diodes 31 are arranged flatly and is provided with a support base 32 to support the light-emitting diode flatly, a heat radiation block 33 which is thermally joined to the support base and radiates heat of the light-emitting diodes transmitted to the support base, and an installation base 20 such as a lamp housing to support the support base. The installation base has an arrangement aperture 23 opened to the back and at least a part of the heat radiation block is located in the arrangement aperture. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a novel backlight device and display device. More specifically, the present invention relates to a technology for effectively dissipating heat associated with driving of a light emitting diode with an inexpensive configuration in a backlight device using the light emitting diode as a light source.

  Conventionally, a display having a direct-type backlight device configured to arrange a backlight device on the back side of a transmissive display panel, for example, a transmissive liquid crystal display panel, and to irradiate light to the transmissive display panel from the rear. The device is known. Conventionally, a cold cathode fluorescent lamp (CCFL) has been widely used as a light source of a backlight device used in such a display device, but in recent years, a light emitting diode (LED) has attracted attention. Has been. The light-emitting diode has higher luminance than the CCFL tube, and when a transmissive liquid crystal display panel is used as a display panel, it is particularly promising as a light source that can cope with an increase in the size of the transmissive liquid crystal display panel.

  On the other hand, high-brightness light-emitting diodes generate a large amount of heat, and as the ambient temperature of the light-emitting diodes rises, the brightness and chromaticity of the light-emitting diodes fluctuate and affect the operating characteristics of surrounding semiconductors and electronic components. Efficient heat dissipation is important.

  In the conventional display device, the backlight device has a box-shaped lamp house (mounting base) in which only the front surface, that is, the surface facing the transmissive display panel is opened, and the opening side of the lamp house In many cases, a diffusion plate or the like is arranged on the closed surface, and the light emitting diode is supported on the closed surface side. Further, the inner surface of the lamp house, that is, the bottom surface and the inner surface of the side wall is formed of a highly reflective member in order to effectively use the light of the light emitting diode.

  In the structure of the conventional backlight device described above, since the substrate on which the light emitting diode is mounted is installed on the closed surface of the lamp house via the support base, the heat generated from the light emitting diode is first supported from the substrate. To the base, and then to the lamp house, the temperature of the lamp house is raised.

  On the other hand, heat radiation fins and fans are provided on the back of the lamp house, and the heat of the light emitting diode is radiated indirectly by radiating the heat of the light emitting diode through the lamp house. Because of the problem of strength, it is usually made of an iron-based material, so the thermal conductivity is inferior compared to copper, aluminum, etc., and the heat generated by the light emitting diode cannot be efficiently radiated.

  The inability to efficiently dissipate heat through the lamp house results in a rise in the temperature of the lamp house itself, resulting in a rise in the temperature inside the lamp house and distortion due to the heat of the lamp house itself. This causes deformation of a display panel such as an installed liquid crystal display panel, and causes malfunction and image failure.

  Therefore, in Patent Document 1, the heat of the light-emitting diode transmitted to the LED mounting substrate is conducted to the heat sink protruding from the back of both ends of the sheet metal member by the heat pipe, and the heat is radiated from the heat sink to the air. A light module is described.

  In the backlight module disclosed in Patent Document 1, the heat of the light emitting diode can be released outside the lamp house by projecting the heat sink outside the lamp house, and the heat is trapped in the lamp house. The above problem is solved.

JP 2006-278041 A

  In the backlight module disclosed in Patent Document 1, since heat is transferred between the LED mounting substrate and the heat sink by the heat pipe, between the support base that supports the LED mounting substrate and the heat pipe, and the heat pipe. When it is difficult to join the heat sink to the heat sink without lowering the heat conduction efficiency and at low cost, the light-emitting diodes are arranged with a wide area and used for back lighting of large display panels The increase in cost is unavoidable due to the lengthening of the heat pipe piping path and the consumption of valuable resources due to the use of copper for the pipe.

  In addition, heat transfer efficiency near the heat pipe is good, but other non-heat pipe parts, such as the contact part between the support base of the LED mounting substrate and the lamp house, are directly transferred from the support base to the lamp house. However, the heat dissipation efficiency is not necessarily good.

  In view of the above-described conventional problems, the present invention directly radiates heat generated by the light emitting diodes from the heat radiation block thermally coupled to the support base that supports the light emitting diodes without passing through the lamp house (mounting base). It is an object of the present invention to prevent the temperature rise and thermal distortion of the lamp house from occurring at a low cost structure.

  In order to solve the above-described problem, the backlight device of the present invention is a backlight device in which a plurality of light emitting diodes are arranged in a plane and used as a light source, the support base supporting the light emitting diodes in a plane, A heat dissipating block that is thermally coupled to the support base and dissipates heat of the light emitting diodes transmitted to the support base; and a mounting base that supports the support base, and the mounting base opens at the back surface. And at least part of the heat dissipating block is located in the arrangement opening.

  Further, in order to solve the above-described problem, the display device of the present invention includes a transmissive display panel and a backlight device disposed on the back side of the transmissive display panel, and the transmissive display panel from behind is transmitted by the backlight device. A display device configured to irradiate light on a display panel, wherein the backlight device is supported by a planar support for a light emitting diode and is thermally coupled to the support base and transmitted to the support base. A heat dissipating block that dissipates heat of the light emitting diode, and a mounting base that supports the support base, the mounting base having an arrangement opening that is open to the back, and at least a part of the heat dissipating block. It is located in the arrangement opening.

  In the present invention, since the heat generated by the light emitting diode is directly radiated to the outside of the mounting base via the heat dissipation block, the heat of the light emitting diode is hardly transmitted to the mounting base.

  The best mode for carrying out the backlight device and the display device of the present invention will be described below with reference to the drawings.

  The backlight device of the present invention is a backlight device in which a plurality of light emitting diodes are arranged in a plane and used as a light source, and a support base that supports the light emitting diodes in a plane and is thermally coupled to the support base, A heat dissipating block for dissipating heat of the light emitting diode transmitted to the support base; and a mounting base for supporting the support base, the mounting base having an arrangement opening opened on the back surface, and the heat dissipating block is at least A part thereof is located in the arrangement opening.

  The display device of the present invention includes a transmissive display panel and a backlight device disposed on the back side of the transmissive display panel, and is configured to irradiate the transmissive display panel with light from behind by the backlight device. The backlight device includes: a support base that planarly supports the light emitting diode; and a heat dissipation that is thermally coupled to the support base and dissipates heat of the light emitting diode that is transmitted to the support base. A mounting base that supports the block and the support base, the mounting base having a disposition opening that is open to the back surface, and at least a part of the heat dissipating block is located in the disposition opening;

  In the backlight device and the display device according to the present invention, the mounting base has an arrangement opening, and the mounting base does not form a closed space, but is thermally coupled to the support base that supports the light emitting diode. Since at least a part of the heat dissipation block is located in the arrangement opening, which is a space connected to the space outside the mounting base, the heat of the light-emitting diode transmitted to the heat dissipation block via the support base can be quickly mounted. Heat is released to the space outside the base. Therefore, the temperature of the inside of the mounting base does not increase due to the heat of the light emitting diode, and the heat conduction to the mounting base itself is small, so that there is less possibility that the mounting base is distorted due to the temperature increase.

  Therefore, the temperature rise of the light emitting diode itself is suppressed, which contributes to the stability of the light emitting characteristics of the light emitting diode, prevents deterioration and breakage due to excessive temperature rise of the light emitting diode, and enables stable use at the rated value. Therefore, the life of the light emitting diode is extended, and the temperature rise of the mounting base (lamp house) is prevented. Therefore, the deformation and distortion due to the temperature rise of the mounting base are eliminated, and the transmissive display panel supported by the mounting base is deformed. Occurrence of image quality defects can be avoided, and heat from the light emitting diodes can be prevented from being transmitted to the transmissive display panel via the mounting base, thus eliminating the malfunction of the transmissive display panel caused by heat. Effects.

  In the present specification and claims, the term “thermally coupled” is used to mean “coupled to improve heat transfer”.

  The support base is formed of a material having better heat conductivity than the mounting base. For example, since the mounting base that normally serves as the casing of the backlight device requires high strength, it is formed of an iron-based material, for example, a kind of cold rolled steel plate SPCC. It is made of a good material such as aluminum or copper. Further, the heat dissipating block is also made of a material having better heat conductivity than the mounting base, like the support base.

  As described above, it is desirable that the heat dissipating block is formed of a material having good heat conduction and has a structure with good heat dissipation such as having a large number of heat dissipating fins.

  Further, the support base and the heat dissipation block may be formed separately and joined in a state where heat conduction is good, but a structure for supporting a light emitting diode (LED mounting board on which the LED is mounted) on the front end of the heat dissipation block. That is, a structure in which the support base and the heat dissipation block are integrally formed may be employed.

  The light emitting diode is usually supported by a support base via an LED mounting substrate, but the LED mounting substrate is omitted, and an insulating layer and a current-carrying layer having a required circuit shape are formed on the support base to form a circuit portion. It is also possible to mount a light emitting diode on the circuit portion.

  It is sufficient that at least a part of the heat dissipating block is located in the arrangement opening of the mounting base, and the rear end may protrude rearward from the arrangement opening. Since the rear end portion of the heat dissipation block protrudes rearward from the arrangement opening, the rear end portion of the heat dissipation block is located in the space outside the mounting base, and heat can be reliably radiated out of the mounting base.

  The heat radiation from the heat radiation block may be natural heat radiation, or an electric fan may be installed to promote quicker heat radiation by forced air convection. The electric fan can be provided, for example, by being installed on the back surface of the mounting base or by being installed in the outer casing of the display device.

  Light emitting diodes used as light sources include single color types of R (red), G (green), and B (blue), and white types that mix a single color. The type of diode is not particularly limited.

  As the transmissive display panel of the display device, for example, a transmissive liquid crystal display panel can be applied.

  The backlight device of the present invention can be implemented in the following modes (1) to (3).

  (1) The rear end portion of the heat dissipation block protrudes further rearward from the arrangement opening. Since the rear end portion of the heat dissipation block protrudes rearward from the arrangement opening, the rear end portion of the heat dissipation block is located in the space outside the mounting base, and heat can be reliably radiated out of the mounting base.

  (2) The support base and the heat dissipation block are integrally formed. By reducing the joints between the members, the heat transfer efficiency from the light emitting diode to the heat dissipation block is improved. Furthermore, the number of parts and the number of assembly steps can be reduced, which contributes to cost reduction.

  (3) The heat dissipating block includes a plurality of heat dissipating fins arranged in a comb shape. The contact area with the heat radiation space is increased, and rapid heat radiation becomes possible.

  Each of the above-described embodiments shows only a part of the embodiments of the backlight device of the present invention, and does not hinder the implementation according to the embodiments other than the above-described embodiments. Is also included in the technical scope of the present invention.

  Next, an example of a specific embodiment of the backlight device and the display device of the present invention will be described with reference to FIGS. In the illustrated embodiment, the present invention is applied to a liquid crystal display device and a backlight device used therefor.

  The liquid crystal display device 10 includes a lamp house 20 as a mounting base, and necessary parts and members are supported by the lamp house 20. The lamp house 20 needs to have a predetermined strength in order to support components and members necessary as a liquid crystal display device including a backlight device, and is formed of an iron-based material, for example, SPCC. The lamp house 20 includes a rear surface portion 21 and a peripheral wall portion 22 projecting forward from the peripheral edge portion of the rear surface portion 21, and a plurality of vertically long arrangement openings 23 are arranged in the width direction on the rear surface portion 21. It is preferable that the inner surface of the lamp house 20 has high reflectivity by reflection coating, metal vapor deposition, white film sticking, or the like.

  A plurality of light source units 30 are supported by the lamp house 20. As can be clearly seen in FIG. 4, the light source unit 30 includes a plurality of light emitting diodes 31, a support base 32 that supports the plurality of light emitting diodes 31, and a heat dissipation block 32 that dissipates heat of the light emitting diodes 31 transmitted to the support base 32. Prepare. The support base 32 is formed of a material having high thermal conductivity, for example, aluminum, and has a thick plate shape that is a slightly vertically long rectangle when viewed from the front, and a disposition groove 32a extending in the horizontal direction is formed on the front surface in the vertical direction. Are formed in large numbers. Further, the upper and lower ends of the rear surface of the support base 32 slightly protrude rearward, and the portion between these protrusions is a fitting portion 32b.

  A plurality of light emitting diodes 31 are arranged and supported on the front surface of the support base 32 as described above so as to form a surface light emitter. Specifically, a plurality of light emitting diodes 31 are mounted in an array on the LED mounting substrate 34 formed in a strip shape. As described above, the LED mounting substrate 34 on which the plurality of light emitting diodes 31 are mounted is arranged and fixed in the arrangement groove 32 a of the support base 32. The LED mounting board 34 is fixed to the support base 32 by, for example, a double-sided adhesive tape having good thermal conductivity, but the fixing means is not limited to this. In short, it is only necessary that the light-emitting diodes 31 transmitted to the LED mounting substrate 34 are coupled to each other so that the heat is quickly transferred to the support base 32. It is also possible to omit the LED mounting substrate 34, form an insulating layer and a current-carrying layer having a required circuit shape on the support base 32, form a circuit portion, and mount the light emitting diode 31 on the circuit portion.

  The heat dissipating block 33 is made of a material having high thermal conductivity, for example, aluminum, and has a plate-like base portion 33a having a slightly long rectangular shape when viewed from the front, and a plurality of heat dissipating fins 33b protruding rearward from the rear surface of the base portion 33a. And are integrally formed. The base 33 a has a vertical length equal to the vertical length of the fitting portion 32 b of the support base 32, and a horizontal width equal to the width of the support base 32. The heat radiating fins 33b have a vertically long thin plate shape, and are arranged in a plurality of comb teeth in the horizontal direction on the rear surface of the base portion 33a except for both sides in the horizontal direction. The light source unit 30 is formed by bonding and fixing the base portion 33a of the heat dissipation block 33 to the fitting portion 32b on the back surface of the support base 32. The support base 32 and the heat radiating block 33 are bonded to each other by, for example, a double-sided adhesive tape having good thermal conductivity, but the fixing means is not limited to this. In short, it is only necessary that the light emitting diodes 31 transmitted to the support base 32 are coupled to each other so that the heat is quickly transferred to the heat dissipation block 33. Reference numeral 35 denotes a connector connected to both ends of the LED mounting board 34 for connecting a LED drive circuit (not shown) and the LED mounting board 34 to supply power to the light emitting diode 31.

  The light source unit 30 formed as described above is attached to the attachment base, that is, the lamp house 20 as follows. As can be seen in FIGS. 1, 2, 5, and 6, the heat radiation fin 33 b side of the light source unit 30 is inserted into the arrangement opening 23 of the lamp house 20 from the front side. Then, one of the upper and lower end portions of the rear surface of the support base 32 and the left and right side portions of the rear surface of the base portion 33a of the heat radiating block 33 are in contact with the front opening edge of the arrangement opening 23 of the lamp house 20, Is fixed by bonding or the like. At this time, a means for preventing heat transfer between the light source unit 30 and the lamp house 20, such as an adhesive having low thermal conductivity, may be taken as the fixing means.

  As described above, the plurality of light source units 30 on the rear surface portion 21 of the lamp house 20 are arrayed and supported, and the backlight device 1 which is a surface light emitter by the plurality of light emitting diodes 31 is formed. And the radiation fin 33b of the radiation block 33 will be in the state which protruded back from the arrangement | positioning opening part 23 of the lamp house 20. As shown in FIG. That is, the rear end portion of the radiation fin 33b is located outside the lamp house 20 (see FIGS. 1, 2, and 6). Therefore, when the light emitting diode 31 is energized, it starts to generate heat simultaneously with light emission. The heat generated by the light emitting diode 31 is transmitted to the LED mounting substrate 34, then is transmitted to the heat radiating block 33 through the support base 32, and is radiated from the heat radiating fins 33 b. Thus, most of the heat from the light emitting diode 31 is dissipated from the heat radiation fins 33b to the outside of the lamp house 20, so that the temperature rise of the light emitting diode 31 is suppressed, and the temperature rise of the lamp house 20 and heat are caused. Deformation is suppressed. Furthermore, as described above, since the contact area between the light source unit 30 and the lamp house 20 is small, the heat directly transmitted from the light source unit 30 to the lamp house 20 is extremely small.

  1 to 3, the reflection sheet 40 is in contact with the front surface of the light source unit 30 arranged as described above, that is, the front surface of the support base 32, and the diffusion plate 50 and the optical sheet are further in front of the reflection sheet 40. 60 and the transmissive liquid crystal display panel 70 are arranged to constitute the liquid crystal display device 10.

  The reflection sheet 40 is a sheet processed so that the front surface has light reflectivity, and has a large number of openings 41 that project the light emitting diodes 31 forward, and the light emitting diodes 31 project forward from the openings 41. As described above, the support base 32 is disposed in contact with the front surface. Thereby, a part of the light emitted from the light emitting diode 31 is reflected by the reflection sheet 40 and directed forward, and the light of the light emitting diode 31 is effectively used.

  A side reflection frame 80 is disposed inside the lamp house 20. The side reflection frame 80 has a frame shape that fits inside the lamp house 20 and is formed of white resin, iron-based material with a white film attached, etc., and reflects the light coming from the side. Thus, it is for the purpose of returning to the front. Further, the distance between the light source unit 30 and the diffusion plate 50 is appropriately maintained, and the distance for forming the planar light that is averaged by mixing the light of the individual light emitting diodes 31 is obtained.

  The diffuser plate 50 is disposed at a sufficient diffusion distance from the light source unit 30, and diffuses light from the light source unit 30 to make the luminance distribution uniform.

  The optical sheet 60 has a function of decomposing light incident from the backlight device 1 through the diffuser plate 50 into orthogonal polarization components, a function of compensating for the phase difference of the light wave to widen the viewing angle and preventing coloring, and incident light. It has a function of diffusing, a function of improving luminance, and the like, and is provided to convert light emitted from the backlight device 1 into illumination light having optical characteristics optimal for illumination of the transmissive liquid crystal display panel 70. .

  The transmissive liquid crystal display panel 70 includes a common transparent electrode and a plurality of pixel electrodes arranged in a matrix with a liquid crystal layer sandwiched between the transparent electrodes. A color filter layer corresponding to each color of B, G, and R is formed on each pixel electrode.

  The diffusion plate 50, the optical sheet 60, and the transmissive liquid crystal display panel 70 are supported by the front end portion of the lamp house 20, although detailed illustration is omitted.

  The liquid crystal display device 10 includes a receiving unit such as an analog tuner or a digital tuner that receives terrestrial or satellite waves, a video signal processing unit that processes video signals and audio signals received by the receiving unit, and an audio signal processing unit, respectively. An audio signal output unit such as a speaker that outputs an audio signal processed by the audio signal processing unit may be provided.

  FIG. 7 shows a modification of the light source unit in the backlight device of the present invention. The light source unit 90 according to this modification is different from the light source unit 30 according to the above embodiment in that the shape of the LED mounting substrate 91 is not a strip shape but a flat plate shape. It is almost the same. Therefore, the same parts as those of the light source unit 30 are denoted by the same reference numerals as those of the same parts of the light source unit 30, and the description thereof is omitted.

  The LED mounting substrate 91 has a flat plate shape, and a plurality of light emitting diodes 31 are arranged on the front surface of the LED mounting substrate 91 with a planar extension. Similar to the support base 32, the support base 92 is made of a material having good thermal conductivity, such as aluminum, and has a substantially flat plate shape. An arrangement surface 92a is formed on the front surface of the support base 92 so as to be retracted one step rearward from the upper and lower end portions, and a fitting portion 92b is formed on the rear surface.

  Then, the LED mounting substrate 91 on which the light emitting diode 31 is mounted is fixed to the arrangement surface 92 a on the front surface of the support base 92. As this fixing means, a double-sided adhesive tape having good thermal conductivity is used. Further, the base portion 33 a of the heat dissipation block 33 is fixed to the fitting portion 92 b on the rear surface of the support base 92. Also for this fixing means, a double-sided adhesive tape or the like having good thermal conductivity is used.

  Even in the light source unit 90 according to this modification, the heat of the light emitting diode 31 generated by energization is transmitted to the support base 92 via the LED mounting substrate 91 and further from the support base 92 to the heat dissipation block 33, and Heat is radiated from the 33 heat radiation fins 33b.

  The shapes and structures of the respective parts shown in the illustrated embodiments are merely examples of implementations for carrying out the present invention, and these limit the technical scope of the present invention. It should not be interpreted.

The drawings show an embodiment in which the present invention is applied to a liquid crystal display device and a backlight device used in the liquid crystal display device, and this drawing is a schematic central longitudinal sectional view. It is a schematic horizontal sectional view. It is a whole exploded perspective view. FIG. 4 is an enlarged perspective view of a portion IV surrounded by a circle in FIG. 3, that is, a light source unit. It is a schematic perspective view which shows the whole backlight apparatus from the front in the state which isolate | separated one light source unit. It is a schematic perspective view which shows the whole backlight apparatus seeing from the back in the state which isolate | separated one light source unit. It is a disassembled perspective view which shows the modification of a light source unit.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Backlight apparatus, 10 ... Liquid crystal display device (display apparatus), 20 ... Lamp house (mounting base), 23 ... Arrangement | positioning opening part, 31 ... Light emitting diode, 32 ... Support base, 33 ... Radiation block, 33b ... Radiation fin , 70 ... Transmission type liquid crystal display panel (transmission type display panel), 92 ... Support base

Claims (5)

A backlight device in which a plurality of light emitting diodes are arranged in a plane and used as a light source,
A support base for planarly supporting the light emitting diode;
A heat dissipation block that is thermally coupled to the support base and dissipates heat of the light-emitting diode transmitted to the support base;
An attachment base for supporting the support base,
The mounting base has a disposition opening that opens to the back surface, and at least a part of the heat dissipation block is located in the disposition opening. The backlight device according to claim 1, wherein a rear end portion of the heat dissipating block protrudes further rearward from the arrangement opening. The backlight device according to claim 1, wherein the support base and the heat dissipation block are integrally formed. The backlight device according to claim 1, wherein the heat dissipating block includes a plurality of heat dissipating fins arranged in a comb shape. A display device comprising: a transmissive display panel; and a backlight device disposed on a back side of the transmissive display panel, wherein the backlight device irradiates light to the transmissive display panel from behind. ,
The backlight device includes: a support base that planarly supports the light emitting diode; a heat dissipation block that is thermally coupled to the support base to dissipate heat of the light emitting diode that is transmitted to the support base; and the support base. A display device, comprising: a mounting base for supporting, wherein the mounting base has an arrangement opening that is open to a back surface, and at least a part of the heat dissipation block is located in the arrangement opening.

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