JP2008053062A - Backlight device and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify the structure of a backlight unit. <P>SOLUTION: Since a plurality of light source boards 10 each having a plurality of LEDs 11 emitting illumination light mounted thereon are attached to a thermally-conductive soaking plate 20, the LEDs 11 can be cooled by heat radiation of the soaking sheet 20, whereby the service life of each LED 11 can be extended; and the temperatures of the LEDs 11 can be equalized by the soaking plate 20, whereby the illumination light can be emitted to a liquid crystal panel 4 in a uniform and stable state. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a backlight device using an LED element as a light source for illuminating a transmissive liquid crystal panel, and a liquid crystal display device including the backlight device.

  In a liquid crystal display device, liquid crystal is sealed between two transparent substrates, and when a voltage is applied, the orientation of liquid crystal molecules is changed and the light transmittance is changed to optically display a predetermined image or the like. The In this liquid crystal display device, since the liquid crystal itself is not a light emitter, for example, a backlight device that illuminates illumination light using an LED (Light Emitting Diode) element as a light source on the back side of the liquid crystal panel is used. is there.

  In a backlight device including a light emitting diode (hereinafter referred to as LED) as a light source, illumination light is emitted from the LED from the back side of the liquid crystal panel, and this illumination light is diffused, reflected, and guided by each optical sheet. By performing the treatment, the illumination light is irradiated to the liquid crystal panel in a uniform and stable state over the entire surface.

  A backlight device using an LED as a light source needs to cool the temperature of the LED to a predetermined temperature or less in order to ensure the lifetime of the LED (for example, half the luminance time). Since the luminous efficiency of the LED is different if the difference is different, it is necessary to make the temperature of the LED uniform.

  In general, in a backlight device including the LED 100 as a light source, as shown in FIG. 13, the LED 100 is mounted on a light source substrate 110 or the like, and the light source substrate 110 on which the LED 100 is mounted is attached to the basic structure 120 or the like. Therefore, the generated heat generated from the LED 100 has a characteristic of being dissipated in the direction of the arrow A in FIG. 13, that is, toward the light source substrate 110 side. For this reason, in a backlight device including the LED 100 as a light source, the LED 100 is cooled to a predetermined temperature or lower by cooling the light source substrate 110 on which the LED 100 is mounted and heat generated from the LED 100 is conducted.

  For example, in the backlight device of Patent Document 1, a heat plate is attached to a light source substrate through which generated heat generated from an LED is transmitted, and the generated heat is transmitted from the heat plate to a heat sink through a heat pipe and then transmitted to the heat sink. The generated heat is cooled by a cooling fan or the like, so that the light source substrate is cooled, and the LEDs are also cooled to a predetermined temperature or less via the light source substrate.

  However, the cooling means of the backlight device of Patent Document 1 includes a heat plate, a heat pipe, a heat sink, and the like, and has a large number of parts, a heavy weight, and a high cost.

JP 2005-316337 A

  The present invention has been proposed in view of such conventional circumstances, and by efficiently cooling the temperature of the LED element with a simple configuration, the life of the LED is extended, and the temperature of the LED element is simplified. The present invention provides a backlight device capable of irradiating illumination light over the entire surface of the liquid crystal panel in a uniform and stable state, and a liquid crystal display device including the backlight device. Objective.

  In order to achieve the above-described object, a backlight device according to the present invention includes a plurality of light source boards on which a plurality of LED elements for illuminating a transmissive liquid crystal panel from the back side and irradiating illumination light are mounted; A plurality of thermally conductive first heat conducting members each having a substrate mounted on a surface thereof, and the first heat conducting member is opposed to the surface side of the first heat conducting member via a predetermined facing distance; Reflecting means for exposing the LED elements from openings formed respectively at positions corresponding to the LED elements mounted on the light source substrate, and reflecting illumination light emitted from the LED elements to the surface side; and the reflecting means A diffusion light guiding means that diffuses the illumination light incident on the surface side of the reflective means through a predetermined facing interval, diffuses the illumination light incident from the reflective means, and guides the illumination light to the transmissive liquid crystal panel. With.

  In order to achieve the above-described object, a liquid crystal display device according to the present invention includes a transmissive liquid crystal panel and a backlight device that illuminates the transmissive liquid crystal panel from the back side.

  According to the present invention, the LED element can be cooled with a simple configuration by providing the heat conductive first heat conducting member to which the plurality of light source boards on which the plurality of LED elements for irradiating illumination light are mounted. Therefore, the lifetime of the LED element can be extended, and the temperature of the LED element can be made uniform with a simple configuration by the first heat conducting member. And uniform and stable irradiation.

  Hereinafter, a backlight device and a liquid crystal display device to which the present invention is applied will be described with reference to the drawings.

  The liquid crystal display device 1 to which the present invention is applied 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 liquid crystal display device 1 is combined with a liquid crystal panel unit 2 having a transmissive liquid crystal panel 4 and a back side of the liquid crystal panel unit 2. And a backlight unit 3 to which the present invention for irradiating illumination light is applied.

  The liquid crystal panel unit 2 irradiated with illumination light from the back side by the backlight unit 3 includes a liquid crystal panel 4 having a substantially rectangular thin plate shape, and a front frame member 5a and a back frame member 5b for holding the liquid crystal panel 4.

  As shown in FIG. 2, the liquid crystal panel 4 held by the front frame member 5a and the back frame member 5b is composed of a first glass substrate 4a and a second glass substrate 4b, which are held at opposite intervals by spacer beads or the like. Although not shown, liquid crystal is enclosed. On the inner surface of the first glass substrate 4a, for example, a striped transparent electrode, an insulating film, and an alignment film for arranging liquid crystal molecules in a certain direction are provided. In addition, on the inner surface of the second glass substrate 4b, for example, a color filter of three primary colors of light, an overcoat layer for protecting the color filter, a striped transparent electrode, and an orientation for arranging liquid crystal molecules in a certain direction. A film or the like is provided.

  In the liquid crystal panel 4 having the above-described configuration, liquid crystal is sealed between the first glass substrate 4a and the second glass substrate 4b, which are opposed to each other by spacer beads, and a voltage is applied to the transparent electrode. Then, the liquid crystal molecules are aligned in the horizontal direction with respect to the interface by the alignment film made of polyimide resin or the like, and the light transmittance is changed by changing the direction of the liquid crystal molecules. Then, the wavelength characteristics of the illumination light that has been achromatic and whitened by the backlight unit 3 are made full color by the color filter provided on the liquid crystal panel 4, and a predetermined image or the like is displayed in color on the display screen or the like. The

  The liquid crystal panel 4 is not limited to the above-described configuration, and may be a liquid crystal panel having various configurations conventionally provided.

  The front frame member 5a and the back frame member 5b for holding the liquid crystal panel 4 are formed in a frame shape, and sandwich the outer peripheral edge of the liquid crystal panel 4 via the spacers 2a and 2b and the guide member 2c as shown in FIG. The liquid crystal panel 4 is held.

  In the liquid crystal panel unit 2 configured as described above, the backlight unit 3 is combined on the back side, and illumination light is applied to the liquid crystal panel unit 2 so that a predetermined image or the like is displayed in color. The liquid crystal display device to which the present invention is applied is provided with a backlight unit 3 to which the present invention described below is applied on the back side, so that the backlight unit 3 illuminates the liquid crystal panel unit 2 with illumination light. Is irradiated in a uniform and stable state over the entire surface to improve the image quality and the like.

  As shown in FIG. 2, the backlight unit 3 that is combined with the back side of the liquid crystal panel unit 2 and emits illumination light is mounted with a plurality of light emitting diodes (hereinafter referred to as LEDs) 11 that emit illumination light as light sources. A plurality of light source substrates 10, a soaking plate 20 serving as a first heat conducting member to which the plurality of light source substrates 10 are attached, and an LED 11 of the light source substrate 10 are irradiated through a soaking interval with the soaking plate 20. And an optical sheet block 30 that performs optical processing on the illumination light.

  As shown in FIG. 3, the plurality of light source substrates 10 on which the plurality of LEDs 11 that irradiate illumination light are mounted are glass epoxy substrates having a conductive layer formed on the surface, and are formed in a substantially rectangular thin plate shape. A plurality of LEDs 11 are mounted on the surface of the light source substrate 10 by combining red LEDs, green LEDs, and blue LEDs on substantially the same axis with respect to the longitudinal direction. Each LED 11 is mounted on a wiring pattern (not shown). For example, a connector 12 for connecting a control signal lead wire or the like of the LED 11 is mounted on the wiring pattern. Further, although not shown, a heat dissipation pattern that is electrically insulated from the wiring pattern is provided on the surface of the light source substrate 10, and a plurality of heat conduction through holes connected to the heat dissipation pattern are formed. Yes. The heat conduction through hole is provided by performing a metal plating process such as gold or copper in the heat conduction through hole or filling a heat conductive paste in the heat conduction through hole. Thereby, in the light source substrate 10, heat is conducted from one surface side to the other surface side.

  The light source substrate 10 is not limited to a glass epoxy substrate, and may be a metal core substrate such as aluminum. Further, the light source substrate 10 is not limited to the LED 11 mounted on substantially the same axis with respect to the longitudinal direction.

  Further, as shown in FIG. 4, the light source substrate 10 is attached to the surface of a soaking plate 20 described later, for example, arranged in 3 rows and 6 columns in a matrix. As a mounting method for attaching the light source substrate 10 to the soaking plate 20, although not shown, a thermally conductive double-sided tape excellent in thermal conductivity is used, and the back surface of the light source substrate 10 and the surface of the soaking plate 20 are bonded. Has been. Further, the light source substrates 10 are arranged close to each other in the row direction, that is, the arrow X direction in FIG. 4, and are arranged apart from each other in the column direction, that is, the arrow Y direction in FIG. Further, although not shown, the light source substrates 10 arranged close to each other in the row direction are electrically connected by lead wires.

  The light source substrate 10 is not limited to being arranged in 3 rows and 6 columns in a matrix, and can be appropriately changed depending on the size of the backlight unit 3 and the like. Moreover, as an attachment method for attaching the light source substrate 10 to the soaking plate 20, it may be fastened with screws, bonded with an adhesive having excellent snap fit and thermal conductivity, or the like.

  A plurality of light source substrates 10 are attached to the surface, and the soaking plate 20 serving as the first heat conducting member is an illumination area of the liquid crystal panel 4 made of an aluminum material or a copper material having a high thermal conductivity, as shown in FIG. That is, it is formed in a substantially rectangular thin plate shape having an area substantially equal to the outer shape of the liquid crystal panel 4. Moreover, the heat equalization plate 20 attaches all the light source substrates 10 to the surface with a heat conductive double-sided tape or the like excellent in heat conductivity, so that the heat generated from the LEDs 11 is made uniform by the heat equalization plate 20. Further, a film treatment such as chromite treatment is performed on the back surface of the soaking plate 20 to form a heat dissipating coating so that the heat soaking plate 20 has a high radiation effect and promotes heat dissipation of the soaking plate 20. Is done. Thereby, the soaking plate 20 cools the LEDs 11 by making the generated heat generated from the plurality of LEDs 11 mounted on the plurality of light source substrates 10 attached to the front surface uniform and radiating the generated heat on the back surface. Let

  Further, as shown in FIG. 4, the heat source plate 20 is arranged with the light source substrates 10 spaced apart in the column direction, that is, the arrow Y direction in FIG. 4, thereby arranging the light source substrates 10 and 10. 20a is provided. A plurality of through holes 20b into which an optical stud member 33 described later is inserted are formed in the arrangement portion 20a. The through-holes 20b are arranged in the row direction, that is, five in the arrow X direction in FIG. 4, and three in the column direction, that is, the arrow Y direction in FIG. A total of 15 pieces are arranged. Further, as shown in FIG. 5, the control signal lead wire 13 connected to the connector 12 of the light source substrate 10 is bundled by the clamper 14 in the arrangement portion 20 a, and the arrangement portion 20 a is connected through a drawing opening 15 formed in the soaking plate 20. Thus, the control signal lead wire 13 is pulled in and pulled out.

  Further, as shown in FIG. 2, the back chassis 6 is disposed on the back side of the soaking plate 20 so as to be separated from the soaking plate 20. The back chassis 6 is a basic structure of the backlight unit 3, and has a substantially rectangular thin plate-like main surface portion that is slightly larger than the outer shape of the liquid crystal panel 4 by an aluminum material having mechanical rigidity and high thermal conductivity. 6a and an outer peripheral wall portion 6b combined at the outer peripheral portion with the back frame member 5b around the main surface portion 6a. The back chassis 6 is disposed on the back side of the soaking plate 20 with a plurality of spacers 7 therebetween, and an air layer 8 is provided between the soaking plate 20 and the back chassis 6.

  The spacer 7 is made of an aluminum material having mechanical rigidity and high thermal conductivity. As shown in FIG. 2, the spacer 7 is disposed between the soaking plate 20 and the back chassis 6 in contact with each other. It is installed. Further, as shown in FIG. 4, eight spacers 7 are arranged at substantially equal intervals in the vicinity of the substantially outer peripheral edge portion of the soaking plate 20, and soaking is performed using a thermally conductive double-sided tape or the like having excellent thermal conductivity. The plate 20 and the back chassis 6 are attached. Thereby, the spacer 7 conducts heat generated from the LEDs 11 from the soaking plate 20 to the back chassis 6.

  Note that the number and arrangement position of the spacers 7 are not limited to this, and can be appropriately changed depending on the size of the backlight device. Moreover, as an attachment method for attaching the spacer 7 to the soaking plate 20, it may be fastened with screws, bonded with an adhesive having excellent snap fit and thermal conductivity, or the like.

  Further, as shown in FIG. 2, a plurality of insertion holes 6c into which a plurality of optical stud members 33 described later are inserted and erected are formed in the main surface portion 6a of the back chassis 6. As shown in FIG. 4, the insertion holes 6 c have 5 in the row direction corresponding to the arrangement positions of the through holes 20 b provided in the arrangement portion 20 a between the light source substrates 10 and 10 attached to the soaking plate 20. 15 in total, 3 in the row direction.

  Further, as shown in FIGS. 2 and 6, the main surface portion 6 a of the back chassis 6 has an outside air in the air layer 8 between the soaking plate 20 and the back chassis 6 provided via the spacer 7 from the outside. Or the openings 9a to 9d (hereinafter, the openings 9a to 9d are also simply referred to as the openings 9) from which the air in the air layer 8 is exhausted to the outside, An exhaust fan 40 is provided as exhaust means for exhausting the air in the air layer 8 to the outside.

  The openings 9 have a substantially rectangular shape in plan view, and are formed at four locations near the four corners of the main surface 6 a of the back chassis 6. Further, the openings 9a and 9b are provided on the upper side after the assembly of the back chassis 6, and the openings 9c and 9d are provided on the lower side after the assembly of the back chassis 6.

  Exhaust fans 40 and 40 serving as exhaust means for exhausting the air in the air layer 8 to the outside are disposed on the back surfaces of the openings 9a and 9b provided on the upper side. In addition, the exhaust fans 40, 40 are externally opened from the openings 9 a, 9 b provided on the upper side in the air layer 8 heated by the heat generated by the LEDs 11 being radiated on the back surface of the soaking plate 20. To exhaust. The air layer 8 is ventilated by the outside air being taken in from the openings 9c and 9d provided on the lower side by the exhaust fans 40 and 40 and exhausted to the outside from the openings 9a and 9b provided on the upper side. . Therefore, the inside of the air layer 8 of the soaking plate 20 is cooled by ventilation by the exhaust fans 40 and 40.

  The number of openings 9 is not limited to four, and can be changed as appropriate depending on the size of the backlight device and the like. Further, the shape of the opening 9 can be changed as appropriate, for example, corresponding to the shape of the exhaust fan 40.

  Although not shown in the figure, the soaking plate 20 is provided in, for example, two parts in the longitudinal direction, and the temperature distribution of the soaking plate 20 is simulated to disperse the heat at the substantially upper center that shows a high temperature. The entire temperature of the soaking plate 20 may be made uniform by cooling with ventilation.

  Specifically, the soaking plate 20 provided in two parts is insulated by providing a heat insulating material or the like between the soaking plates 20, 20. For this reason, in the soaking plate 20, the substantially central upper part of each soaking plate 20 exhibits a high temperature, and the region showing this high temperature and the opening 9 into which outside air is taken in or exhausted by ventilation cooling are provided. It is almost matched.

  As a result, the soaking plate 20 is ventilated and cooled by the exhaust fan 40, and the soaking plate 20 is divided into two parts so that the substantially central upper part is intensively cooled by ventilation. The temperature is made uniform.

  In addition, the number of division | segmentation of the soaking | uniform-heating plate 20 is not limited to this, According to the magnitude | size of the backlight unit 3, etc., it can change suitably.

  Further, as shown in FIG. 7A, an air guide plate 50 serving as an air guide means for guiding the outside air taken in from the openings 9c and 9d is formed on the surface of the main surface portion 6a of the back chassis 6, and soaking is performed. As a result of simulating the temperature distribution of the plate 20, the central upper part showing a high temperature is intensively cooled, and the openings 9 c and 9 d through which the outside air is taken into the air layer 8 and the vicinity thereof are locally cooled. By preventing this, the entire temperature of the soaking plate 20 may be made uniform.

  Specifically, the air guide plate 50 is formed so as to protrude in a substantially C shape in plan view so that the upper surface is in contact with the back surface of the heat equalizing plate 20. Further, in the air guide plate 50, the direction of the arrow B in FIG. 7A, that is, the outside air taken in from the openings 9c and 9d flows to the substantially upper center of the soaking plate 20, and is exhausted through the openings 9a and 9b. To guide.

  As a result, the heat equalizing plate 20 is ventilated and cooled by the exhaust fan 40, and the substantially central upper portion showing a high temperature as a result of simulating the temperature distribution of the heat equalizing plate 20 by the air guide plate 50 is intensively cooled. Thus, the entire temperature of the soaking plate 20 is made uniform. In addition, the air guide plate 50 is locally cooled by the outside air being intensively blown to the openings 9c and 9d through which the outside air is taken into the air layer 8 and the back surface of the heat equalizing plate 20 facing the vicinity thereof. And the temperature of the soaking plate 20 is made uniform.

  Note that the upper surface of the air guide plate 50 is not limited to be formed so as to be in contact with the back surface of the soaking plate 20, and may be formed so as to protrude partially leaving a gap.

  As a cooling means, instead of the exhaust fan 40 or in combination with the exhaust fan 40, the divided heat equalizing plate 20 and the air guide plate 50 may be provided.

  The openings 9a and 9b are not limited to the exhaust fans 40 and 40, and an intake fan serving as an intake means for taking outside air into the air layer 8 from the outside may be provided. Further, exhaust fans 40 and 40 or intake fans may be attached to the back chassis 6 in the openings 9c and 9d, and the soaking plate 20 may be ventilated and cooled. Further, the exhaust fans 40, 40 are disposed on one side of the openings 9a, 9b provided on the upper side or the openings 9c, 9d provided on the lower side, and the intake fans are disposed on the other side. The heat plate 20 may be ventilated and cooled. Further, ventilation cooling may be performed by outside air without providing the exhaust fan 40 and / or the intake fan.

  Here, as shown in FIG. 7B, another use example of the air guide plate 50 when the intake fan 41 is disposed on the back surface of the openings 9c and 9d of the back chassis 6 will be described. Specifically, the air guide plate 50 is substantially L-shaped in plan view so that the upper surface contacts the back surface of the heat equalizing plate 20 along the edge on the front surface side of the openings 9c and 9d of the back chassis 6. Protrusions are formed.

  Further, the air guide plate 50 restricts the outside air from flowing into the space 6d surrounded by the dotted line in FIG. 7B between the inner wall of the outer peripheral wall portion 6b of the back chassis 6 and the air guide plate 50, It guides so that external air may be supplied intensively in the direction of arrow C in FIG.

  As a result, the heat equalizing plate 20 is ventilated and cooled by the intake fan 41, and the temperature distribution of the heat equalizing plate 20 is simulated by the air guide plate 50, and a substantially central upper portion showing a high temperature is intensively cooled by ventilation. As a result, the entire temperature of the soaking plate 20 is made uniform. Further, the air guide plate 50 is locally cooled by the outside air being intensively blown onto the openings 9c and 9d through which the outside air is taken into the air layer 8 and the back surface of the soaking plate 20 facing the openings 9c and 9d. And the temperature of the soaking plate 20 is made uniform.

  Note that the upper surface of the air guide plate 50 is not limited to be formed so as to be in contact with the back surface of the soaking plate 20, and may be formed so as to protrude partially leaving a gap.

  Further, the main surface portion 6a of the back chassis 6 is not provided with the opening 9, and the temperature of the LED 11 is made uniform by the soaking plate 20, and the generated heat generated from the LED 11 by the soaking plate 20 and the back chassis 6 is dissipated. By doing so, the LED 11 may be cooled.

  Further, the back chassis 6 is disposed on the back side of the soaking plate 20 with a plurality of spacers 7 interposed therebetween, and an air layer 8 is provided between the soaking plate 20 and the back chassis 6. It is not limited to this. Further, the back chassis 6 is attached so that, for example, the soaking plate 20 and the back chassis 6 are in direct contact with each other, so that the temperature of the LED 11 is made uniform by the soaking plate 20, and the LED 11 is made by the soaking plate 20 and the back chassis 6. As long as the LED 11 can be cooled by dissipating the heat generated from the heat, the soaking plate 20 and the back chassis 6 do not have to be spaced apart.

  As shown in FIG. 2, the optical sheet block 30 attached to the back chassis 6 is provided to face the back side of the liquid crystal panel 4 through the heat equalizing plate 20 and the facing distance.

  In addition, the optical sheet block 30 is a reflection sheet that serves as a reflection means for reflecting the illumination light emitted from the LED 11 that is opposed to the surface side of the heat equalizing plate 20 with a predetermined facing distance from the LED 11 to the surface side. 31 is a diffusion light guide means that is opposed to the reflective sheet 31 on the surface side of the reflective sheet 31 with a predetermined facing distance, diffuses the incident illumination light, and guides the illumination light to the transmissive liquid crystal panel 4 And a plurality of optical stud members 33 that respectively define the facing distance between the soaking plate 20 and the reflecting sheet 31 and the facing distance between the reflecting sheet 31 and the diffusing light guiding plate 32.

  In addition, the optical stud member 33 is inserted into the back chassis 6 in accordance with the arrangement position of the through hole 20b provided in the arrangement portion 20a between the light source substrates 10 and 10 attached to the soaking plate 20. 6 are arranged in a row direction, that is, five in the direction of the arrow X in FIG. 4, and three in the column direction, that is, in the direction of the arrow Y in FIG.

  As shown in FIG. 2, a reflection sheet 31 serving as a reflection means facing the surface of the heat equalizing plate 20 with a predetermined distance from the heat equalizing plate 20 is a surface of an aluminum plate base material having mechanical rigidity. A reflective material made of foamed PET (Polyethylene Terephthalate) containing a fluorescent material and having a high reflectivity characteristic is provided on the surface, and is a substantially rectangular thin plate having substantially the same shape as the soaking plate 20. Is formed. In addition, as shown in FIG. 3, openings 31 a are formed in the reflection sheet 31 at positions corresponding to the LEDs 11 mounted on the light source substrate 10. The opening 31a exposes the LED 11 mounted on the light source substrate 10 to the front surface side. Further, the reflection sheet 31 reflects the illumination light emitted from the LED 11 exposed on the front surface side to the front surface side, so that the illumination light is guided to a diffusion light guide plate 32 serving as a diffusion light guide unit described later. The In addition, as shown in FIG. 4, an optical stud member 33 described later is inserted into the reflection sheet 31, and five through holes 31 b corresponding to the arrangement positions of the through holes 20 b of the heat equalizing plate 20 are provided in the row direction. , 3 in the column direction, 15 in total.

  In addition, the base material of the reflection sheet 31 is not limited to an aluminum plate, For example, a silver plate, a stainless plate, etc. may be used. The reflection sheet 31 may be made of a silver plate having a mirror surface, a stainless plate, an aluminum plate, or the like without providing a reflection material. Further, when the reflective sheet 31 is a relatively small liquid crystal display device, the reflective sheet 31 may be formed of a reflective material made of, for example, foaming PET (Polyethylene Terephthalate) containing a fluorescent agent.

  A diffusion light guide that opposes the surface of the reflection sheet 31 with a predetermined facing interval, diffuses illumination light incident from the reflection sheet 31, and guides the illumination light to the transmissive liquid crystal panel 4. As shown in FIG. 2, the diffusion light guide plate 32 as a means is formed into a substantially rectangular thin plate shape substantially the same shape as the reflective sheet 31 by using a milky white synthetic resin material having a light guide property, such as an acrylic resin or a polycarbonate resin. Has been.

  On the surface of the diffusion light guide plate 32 on the liquid crystal panel 4 side, a substantially rectangular shape that is substantially the same shape as the diffusion light guide plate 32, and a plurality of optical function sheets 34 are laminated. The optical function sheet 34 laminated on the surface of the diffusion light guide plate 32 is not limited thereto, but is an illumination that is irradiated from the LED 11 mounted on the light source substrate 10 and guided to the liquid crystal panel 4. A polarizing film having a function of decomposing light into polarized light components orthogonal to each other, a diffusion film having a function of diffusing illumination light, and a brightness improving film for improving brightness.

  In addition, the diffusion light guide plate 32 has the illumination light incident from the back surface on the reflective sheet 31 side refracted, reflected, and diffused inside, so that the optical function sheet 34 laminated on the surface covers the entire surface. Illumination light is guided in a uniform state.

  Further, the diffusion light guide plate 32 is attached to an outer peripheral wall portion 6b of the back chassis 6 to be described later with an outer peripheral portion held by a bracket member 32a.

  As shown in FIG. 2, the optical stud member 33 that defines the distance between the optical sheets facing each other is, for example, light-white or transparent light having a light guiding property such as a polycarbonate resin and mechanical rigidity and a certain degree of elasticity. The reflecting member is integrally formed. The optical stud member 33 has a main body portion 33a whose front end is abutted against the back surface of the diffusion light guide plate 32 and defines a facing distance between the diffusion light guide plate 32 and the back chassis 6, and a base end of the main body portion 33a. And a mounting portion 33b formed continuously.

  The main body portion 33a that defines the facing distance between the diffusion light guide plate 32 and the back chassis 6 has a bottom surface that is larger in diameter than the through hole 31b of the reflection sheet 31 on the front end side of the main body portion 33a, and gradually toward the front end. It has a conical shape with a small diameter.

  The main body 33a has a conical bottom surface in contact with the surface of the reflection sheet 31, and a tip portion is brought into contact with the back surface of the diffusion light guide plate 32 at a point or a small area so as to abut on the diffusion light guide. The facing interval between the plate 32 and the reflecting sheet 31 is defined, and the parallelism between these opposing main surfaces is positioned with high accuracy over the entire surface.

  The mounting portion 33b formed continuously from the base end of the main body portion 33a is inserted into the insertion hole 6c of the back chassis 6, and the distal end is larger in diameter than the insertion hole 6c at the outer peripheral portion of the base end. Is formed so as to be supported around the back side of the insertion hole 6c.

  In addition, you may provide the diffusion plate 61 in the optical sheet block 30 so that the illumination light irradiated from LED11 may have sufficient illumination light distribution.

  Here, an assembling method of the backlight unit 3 will be described.

  First, as shown in FIG. 4, the light source substrate 10 on which the plurality of LEDs 11 are mounted is attached to the surface of the soaking plate 20 arranged in a matrix of 3 rows and 6 columns. As shown in FIG. 2, the exhaust fan 40 is already attached to the back side of the opening 9 on the back side of the soaking plate 20, separated from the soaking plate 20 via a plurality of spacers 7. A back chassis 6 is provided. Thereby, an air layer 8 is provided between the soaking plate 20 and the back chassis 6.

  Next, the reflection sheet 31 is placed on a reflection sheet support (not shown) provided around the soaking plate 20. Further, the reflection sheet 31 is disposed so that the through hole 31 b of the reflection sheet 31 faces the through hole 20 b of the soaking plate 20.

  Next, the mounting portion 33 b of the optical stud member 33 is pushed into the insertion hole 6 c of the back chassis 6 from the surface side of the reflection sheet 31 through the through hole 31 b of the reflection sheet 31 and the through hole 20 b of the soaking plate 20. It is. The mounting portion 33b of the optical stud member 33 is supported around the back surface side of the insertion hole 6c.

  At this time, in each optical stud member 33, the attachment portion 33 b is supported around the back surface side of the insertion hole 6 c and the conical bottom surface portion of the main body portion 33 a is brought into contact with the surface of the reflection sheet 31. Attached to the back chassis 6. As a result, each optical stud member 33 holds the reflection sheet 31 in the thickness direction between the reflection sheet support portion (not shown) provided around the reflection sheet 31 and the conical bottom surface portion of the main body portion 33a. The facing interval between the heat plate 20 and the reflective sheet 31 is defined, and the parallelism between these opposing main surfaces is positioned with high accuracy over the entire surface.

  Next, the front end portion of each optical stud member 33 is abutted against the back surface of the diffusion light guide plate 32, and the diffusion light guide plate 32 is attached to the outer peripheral wall portion 6b of the back chassis 6 described later using a bracket member 32a. It is attached.

  As a result, each optical stud member 33 has its tip portion contacted and abutted against the back surface of the diffusion light guide plate 32 at a point or a narrow area, thereby defining the facing distance between the diffusion light guide plate 32 and the reflection sheet 31. The parallelism between these opposing main surfaces is positioned with high accuracy over the entire surface.

  In the backlight unit 3 configured as described above, a plurality of light source substrates 10 on which a plurality of LEDs 11 that irradiate illumination light are mounted on a heat conductive soaking plate 20 are attached. The heat generated from the LED 11 is conducted to the LED 11, and the heat generated from the LED 11 is dissipated by the soaking plate 20, whereby the LED 11 can be cooled. Therefore, the life of the LED 11 can be extended. Moreover, since the backlight unit 3 can equalize | homogenize the temperature of LED11 with the soaking | uniform-heating plate 20, it can irradiate illumination light with respect to the liquid crystal panel 4 over the whole surface in a uniform and stable state.

  In the backlight unit 3, the back chassis 6 is disposed on the back side of the soaking plate 20 with a plurality of spacers 7 therebetween, and an air layer 8 is provided between the soaking plate 20 and the back chassis 6. Since the back chassis 6 has a plurality of openings 9, outside air is taken into the air layer 8 from the opening 9 on one side, and heat is released from the opening 9 on the other side by the soaking plate 20. Since the warmed air is exhausted to the outside, the soaking plate 20 can be intensively cooled by cooling, and the LED 11 can be cooled. Therefore, the life of the LED 11 can be extended. Moreover, since the backlight unit 3 can equalize | homogenize the temperature of LED11 with the soaking | uniform-heating plate 20, it can irradiate illumination light with respect to the liquid crystal panel 4 over the whole surface in a uniform and stable state.

  In the backlight unit 3, exhaust and / or intake fans 40 and 41 are disposed on the back surface of the opening 9 on one side of the back chassis 6, and the exhaust and / or intake fans 40 and 41 are provided from the one opening 9. The outside air is taken into the air layer 8 and the air heated by the heat dissipation by the soaking plate 20 is exhausted to the outside through the other opening 9, so that the soaking plate 20 can be intensively cooled by ventilation. Since the LED 11 can be cooled, the life of the LED 11 can be extended. Moreover, since the backlight unit 3 can equalize | homogenize the temperature of LED11 with the soaking | uniform-heating plate 20, it can irradiate illumination light with respect to the liquid crystal panel 4 over the whole surface in a uniform and stable state.

  The backlight unit 3 has a heat radiation coating formed on the back surface of the soaking plate 20 by a chromite treatment or the like, and is made black. Therefore, the backlight unit 3 has a high radiation effect and promotes heat radiation of the soaking plate 20. As a result, the LEDs 11 can be intensively cooled, so that the lifetime of the LEDs 11 can be extended. Moreover, since the backlight unit 3 can equalize | homogenize the temperature of LED11 with the soaking | uniform-heating plate 20, it can irradiate illumination light with respect to the liquid crystal panel 4 over the whole surface in a uniform and stable state.

  Next, another example of the backlight unit 60 when the diffusion plate 61 is provided so that the illumination light emitted from the LED 11 has a more sufficient illumination light distribution will be described. Hereinafter, when the backlight unit 60 has the same configuration as the backlight unit 3 described above, the same reference numerals are given and the description thereof is omitted.

  As shown in FIG. 8, the backlight unit 60 is provided with a diffusion plate 61 that is opposed to the reflective sheet 31 via a predetermined facing distance on the surface side of the reflective sheet 31.

  The diffusion plate 61 is formed in a substantially rectangular thin plate shape that is substantially the same shape as the reflective sheet 31 with a transparent synthetic resin material, for example, an acrylic resin. Further, the diffusing plate 61 guides the illuminating light to the diffusing light guide plate 32 as the illuminating light incident from the back surface on the reflecting sheet 31 side is refracted, reflected and diffused inside. Further, the diffusion plate 61 is formed with a plurality of through holes 61a into which the optical stud member 33 is inserted. As shown in FIG. 4, a total of 15 through holes 61a are formed corresponding to the arrangement positions of the through holes 20b of the soaking plate 20, 3 in the row direction and 3 in the column direction.

  As shown in FIG. 8, the optical stud member 33 that defines the distance between the optical sheets facing each other includes a main body 33a that defines the distance between the diffusion light guide plate 32 and the back chassis 6, and the tip of the main body 33a. On the side, the bottom surface has a larger diameter than the through hole 61a of the diffusion plate 61, and is formed in a conical shape with a gradually decreasing diameter toward the tip.

  The main body 33a has a conical bottom surface in contact with the surface of the diffusing plate 61, and a tip portion is brought into contact with the back surface of the diffusing light guide plate 32 at a point or a small area, so that the diffusing light guide The opposing interval between the plate 32 and the diffusion plate 61 is defined, and the parallelism between these opposing main surfaces is positioned with high accuracy over the entire surface.

  In addition, the main body portion 33a is formed with a diffusion plate defining portion 62 having a larger diameter than the through hole 61a of the diffusion plate 61 with a predetermined distance from the conical bottom surface. In the diffusion plate defining portion 62, the surface of the diffusion plate defining portion 62 is in contact with the back surface of the diffusion plate 61. Further, the main body portion 33a is formed with a reflecting sheet defining portion 63 having a larger diameter than the through hole 31b of the reflecting sheet 31 protruding from the diffusion plate defining portion 62 with a predetermined distance. In the reflection sheet defining portion 63, the back surface of the reflection sheet defining portion 63 is in contact with the surface of the reflection sheet 31.

  Here, a method for assembling the backlight unit 60 will be described.

  As shown in FIG. 8, the mounting portion 33 b of the optical stud member 33 is inserted into the insertion hole of the back chassis 6 from the surface side of the reflection sheet 31 through the through hole 31 b of the reflection sheet 31 and the through hole 20 b of the soaking plate 20. It is pushed into 6c. The mounting portion 33b of the optical stud member 33 is supported around the back surface side of the insertion hole 6c. At this time, each optical stud member 33 is attached to the back chassis 6 by the attachment portion 33b being supported around the back side of the insertion hole 6c and the reflection sheet defining portion 63 being in contact with the surface of the reflection sheet 31. It is attached. As a result, each optical stud member 33 holds the reflection sheet 31 in the thickness direction between the reflection sheet support portion (not shown) provided around the reflection sheet 31 and the reflection sheet defining portion 63, so that the soaking plate 20 The facing interval with the reflecting sheet 31 is defined, and the parallelism between these opposing main surfaces is positioned with high accuracy over the entire surface.

  Next, in the through holes 61a of the diffusion plate 61, the tip portions of the respective optical stud members 33 facing each other are fitted and combined. The conical bottom surface portion of the main body portion 33 a is in contact with the surface of the diffusion plate 61. At this time, the diffusion plate defining portion 62 is in contact with the back surface of the diffusion plate 61. Accordingly, each optical stud member 33 holds the diffusion plate 61 between the reflection sheet 31 and the diffusion plate 61 by sandwiching the diffusion plate 61 in the thickness direction between the diffusion plate defining portion 62 and the conical bottom surface on the distal end side of the main body portion 33a. The opposing interval is defined, and the parallelism between these opposing main surfaces is positioned with high accuracy over the entire surface.

  Next, the front end portion of each optical stud member 33 is abutted against the back surface of the diffusion light guide plate 32, and the diffusion light guide plate 32 is attached to the outer peripheral wall portion 6b of the back chassis 6 described later using a bracket member 32a. It is attached. As a result, each optical stud member 33 has its tip portion contacted and abutted against the back surface of the diffusion light guide plate 32 at a point or a narrow area, thereby defining the facing distance between the diffusion plate 61 and the diffusion light guide plate 32. The parallelism between these opposing main surfaces is positioned with high accuracy over the entire surface.

  In the backlight unit 60 configured as described above, the illumination light is repeatedly reflected by the diffusion plate 61 between the diffusion plate 61 and the reflection sheet 31, so that the illumination light is uniformly distributed over the entire surface. And is incident on the diffusion light guide plate 32.

  In addition, as shown in FIG. 8, you may provide the light control dot 61b in the back surface which opposes LED11 of the light source board | substrate 10 in the diffusion plate 61. As shown in FIG. The dimming dot 61b is formed by screen printing or the like using a reflective ink in which a light-blocking agent such as titanium oxide or barium sulfide or a diffusing agent such as glass powder or silicon oxide is mixed. The incident light amount of the illumination light incident on the diffusion light guide plate 32 may be regulated by the light control dots 61b.

  Next, as a result of simulating the temperature distribution of the soaking plate 20, the second heat conducting member 70 that intensively cools the substantially central upper portion showing a high temperature and makes the entire temperature of the soaking plate 20 uniform is obtained. The backlight unit 80 having the above will be described. Hereinafter, when the backlight unit 80 has the same configuration as the backlight units 3 and 60 described above, the same reference numerals are given and description thereof is omitted.

  As shown in FIGS. 9 and 10, the second heat conducting member 70 is made of a highly heat conductive aluminum material or the like, and is formed in a substantially T shape in plan view. It is arranged in contact. The first piece of the second heat conducting member 70 formed in a T shape in plan view is disposed in the left-right direction so as to correspond to the substantially central upper portion showing a high temperature. In addition, the second piece of the second heat conducting member 70 provided in a direction substantially perpendicular to the first piece is disposed in the vertical direction so as to correspond to the substantially central upper portion showing a high temperature. .

  As a result, the heat equalizing plate 20 is ventilated and cooled by the exhaust fan 40, and the temperature distribution of the heat equalizing plate 20 is simulated by the second heat conducting member 70. As a result, a substantially central upper portion showing a high temperature is concentrated. By cooling, the entire temperature of the soaking plate 20 is made uniform.

  In addition, the shape of the 2nd heat conductive member 70 is not limited to this, It can change suitably according to the magnitude | size etc. of a backlight apparatus.

  In the backlight unit 80 configured as described above, the second heat conductive member 70 is disposed so as to be in contact with the air layer 8 between the soaking plate 20 and the back chassis 6, respectively, and the high temperature is increased. By conducting the heat at the substantially upper center of the illustrated soaking plate 20 to the back chassis 6 in a concentrated manner, the substantially upper center can be cooled intensively, and the temperature of the soaking plate 20 can be made uniform. As a result, the temperature of the LED 11 can be made uniform, and the temperature unevenness of the LED 11 can be prevented. Accordingly, the backlight unit 80 can extend the life of the LED 11 and can irradiate the liquid crystal panel 4 with illumination light over the entire surface in a uniform and stable state.

  In order to confirm the effect of the backlight unit 3 to which the present invention is applied, the following experiment was performed. In this experiment, the temperature of the LED 11 and the back chassis 6 during illumination light irradiation was measured from the LED 11 of the backlight unit 3 to which the present invention was applied. FIG. 11 shows the temperature measurement points at this time.

  As shown in FIG. 11, the temperature measurement method of the LED 11 is a total of approximately three rows and three columns of thermocouples arranged in a matrix between the light source substrate 10 and the soaking plate 20 from the back side of the back chassis 6. Temperature measurement was carried out by arranging in nine places p1 to p9. The temperature measurement method of the back chassis 6 measured the temperature by arrange | positioning the thermocouple in nine places p1-p9 on the back surface of the back chassis 6. FIG.

  In addition, since the structure of the backlight unit 3 mentioned later was left-right symmetric, these temperature measurement measured only the left side from the back view center of the soaking | uniform-heating plate 20. FIG. Moreover, the power consumption of LED11 at the time of illumination light irradiation was set to 220W.

  FIG. 12 shows the results of measuring the temperature of the LED 11 and the back chassis 6 by the above-described temperature measurement method. FIG. 12 shows the maximum temperature of LED 11 (LED MAX), the minimum temperature of LED 11 (LED MIN), and the maximum temperature of back chassis 6 among the nine temperature measurement points where the temperature of LED 11 and back chassis 6 was measured. (Back chassis MAX) is shown.

  Here, the maximum temperature that guarantees stable operation of the LED 11 is set to 60 ° C., and the maximum temperature that guarantees stable operation of, for example, an electronic device for LED 11 drive control attached to the back chassis is set to 50 ° C. did.

  As shown in FIG. 12, (A) shows that a plurality of light source substrates 10 on which a plurality of LEDs 11 are mounted are attached to a soaking plate 20, and the soaking plate 20 is placed between the soaking plate 20 and the back chassis 6. It is a temperature measurement result of the backlight unit 3 provided with the layer 8 and disposed on the back chassis 6. (B) is a temperature measurement result of the backlight unit 3 in which the opening portions 9 are provided in the vicinity of the four corners of the main surface portion of the backlight chassis 6 in the backlight unit 3 of (A). (C) is a temperature measurement result of the backlight unit 3 in which the exhaust fans 40, 40 are disposed in the openings 9a, 9b provided on the upper side of the backlight unit 3 in (B). (D) is a temperature measurement result of the backlight unit 3 in which the back surface of the soaking plate 20 of the backlight unit 3 of (C) is subjected to chromite treatment to form a heat dissipation coating. (E) is a temperature measurement result of the backlight unit 3 in which the second heat conducting member 70 is provided between the soaking plate 20 and the back chassis 6 of the backlight unit 3 of (D). It is. That is, the backlight units 3 of (A) to (E) increase the cooling means as they go from the backlight unit 3 of (A) to the backlight unit 3 of (E).

  As shown in FIG. 12, the backlight unit 3 of (A) to (E) has a maximum temperature (LED MAX) of the LED 11 as it goes from the backlight unit 3 of (A) to the backlight unit 3 of (E). ), The minimum temperature (LED MIN) of the LED 11 and the maximum temperature (back chassis MAX) of the back chassis 6 are reduced, and it can be confirmed that the cooling effect is increased.

  Moreover, the backlight unit 3 of (D)-(E) can confirm that the maximum temperature of LED11 is about 60 degrees C or less, and exists in the temperature range where operation | movement of LED11 is performed stably. Further, the backlight unit 3 of (B) to (E) has a maximum temperature of the back chassis 6 of 50 ° C. or less, and is in a temperature range in which operations of electronic devices and the like attached to the back chassis 6 are stably performed. Can be confirmed.

In addition, as shown in FIG. 12, the backlight unit 3 of (A) to (E) has a maximum temperature of the LED 11 as it goes from the backlight unit 3 of (A) to the backlight unit 3 of (E). When the difference D between (LED MAX) and the minimum temperature (LED MIN) of the LED 11, that is, the difference D between the maximum temperature characteristic line 90 of the LED 11 and the minimum temperature characteristic line 91 of the LED 11, The difference D gradually decreases from the backlight unit 3,
It can be confirmed that the temperature of the LED 11 is uniform.

  The maximum temperature (back chassis MAX) of the back chassis 6 of the backlight unit 3 of (E) is provided with the second heat conducting member 70, and the heat of the soaking plate 20 is the second heat conducting member 70. The maximum temperature of the back chassis 6 (back chassis MAX) is increased by being conducted to the back chassis 6 through the LED, but the cooling effect is further enhanced, and the maximum temperature of the LED 11 (LED MAX) and the minimum temperature of the LED 11 (LED It can be confirmed that MIN) is lowered.

  In this experiment, the maximum temperature that guarantees stable operation of the LED 11 is set to 60 ° C., and the maximum temperature that guarantees stable operation of, for example, an electronic device for LED 11 drive control attached to the back chassis is 50 ° C. However, the present invention is not limited to these, and may be set to a higher temperature or a lower temperature depending on the LED 11 or electronic device to be mounted, and can be changed as appropriate.

It is a principal part disassembled perspective view of the liquid crystal display device to which this invention is applied. It is a principal part longitudinal cross-sectional view of the liquid crystal display device to which this invention is applied. It is a principal part perspective view of the light source substrate and the opening part of a reflective sheet. It is a rear view of the assembly of a light source substrate, a soaking plate, and a back chassis. It is a principal part perspective view of the assembly of a light source board | substrate and a soaking | uniform-heating plate. It is a top view of a back chassis. It is a top view of a back chassis, and (A) is a usage example of a baffle plate when an exhaust fan is provided. (B) is an example of the use of an air guide plate when an intake fan is provided. It is a principal part longitudinal cross-sectional view of the liquid crystal display device when a diffusion plate is provided. It is a top view of a back chassis at the time of providing the 2nd heat conduction member. It is a principal part longitudinal cross-sectional view of a liquid crystal display device at the time of providing a 2nd heat conductive member. It is a rear view of the back chassis which showed the temperature measurement location. It is the graph which showed the temperature measurement result of LED and a back chassis. It is the cross-sectional view which showed the thermal radiation characteristic of LED.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Liquid crystal display device, 2 Liquid crystal panel unit, 3 Backlight unit, 4 Liquid crystal panel, 10 Light source board, 11 Light emitting diode (LED), 20 Soaking plate, 30 Optical sheet block, 31 Reflective sheet, 32 Diffusing light guide plate, 33 Optical Stud Member, 34 Optical Function Sheet

Claims (16)

In a backlight device that illuminates a transmissive liquid crystal panel from the back side,
A plurality of light source boards on which a plurality of LED elements for irradiating illumination light are mounted;
A thermally conductive first heat conducting member having a plurality of light source substrates attached to the surface;
Openings formed at positions corresponding to the LED elements mounted on the light source substrate, facing the first heat conductive member with a predetermined facing interval on the surface side of the first heat conductive member. Reflecting means for exposing the LED element from, and reflecting the illumination light emitted from the LED element to the surface side;
Diffusion that is opposed to the surface of the reflecting means through a predetermined facing distance, diffuses the illumination light incident from the reflecting means, and guides the illumination light to the transmissive liquid crystal panel A backlight device comprising light guiding means. The first heat conducting member is formed in an area substantially equal to the illumination area of the liquid crystal panel,
2. The backlight device according to claim 1, wherein the plurality of light source substrates are provided over the entire first heat conducting member. Further, a back chassis is disposed on the back side of the first heat conducting member so as to be separated from the first heat conducting member, and an air layer is provided between the first heat conducting member and the back chassis. Is provided,
The backlight device according to claim 1, wherein a plurality of openings are formed in the back chassis.   4. The backlight device according to claim 3, wherein exhaust and / or intake means are disposed in the opening of the back chassis.   The backlight device according to claim 1, wherein a heat-dissipating film is formed on the back surface of the first heat conducting member.   4. The backlight device according to claim 3, wherein a second heat conductive member that contacts each of the first heat conductive member and the back chassis is disposed.   4. The backlight device according to claim 3, wherein the first heat conducting member is divided.   4. The backlight device according to claim 3, wherein the back chassis is formed with air guiding means for guiding outside air to a central portion of the first heat conducting member. A transmissive LCD panel;
A backlight device that illuminates the transmissive liquid crystal panel from the back side;
The backlight device includes a plurality of light source substrates on which a plurality of LED elements for irradiating illumination light are mounted, a heat conductive first heat conducting member having a plurality of light source substrates attached to the surface, and the first The LED is opened from the opening formed on the surface side of the heat conducting member at a position corresponding to the LED element mounted on the light source substrate so as to face the first heat conducting member with a predetermined facing distance. Reflecting means that exposes the element and reflects the illumination light emitted from the LED element to the surface side, and is opposed to the surface side of the reflecting means with the reflecting means through a predetermined facing distance, and is incident from the reflecting means A liquid crystal display device comprising: a diffusion light guide unit that diffuses the illumination light and guides the illumination light to the transmissive liquid crystal panel. The first heat conducting member is formed in an area substantially equal to the illumination area of the liquid crystal panel,
The liquid crystal display device according to claim 9, wherein the plurality of light source substrates are provided over the entire first heat conducting member. Further, a back chassis is disposed on the back side of the first heat conducting member so as to be separated from the first heat conducting member, and an air layer is provided between the first heat conducting member and the back chassis. Is provided,
The liquid crystal display device according to claim 9, wherein a plurality of openings are formed in the back chassis.   12. The liquid crystal display device according to claim 11, wherein exhaust and / or intake means are disposed in the opening of the back chassis.   The liquid crystal display device according to claim 9, wherein a heat radiating film is formed on a back surface of the first heat conducting member.   The liquid crystal display device according to claim 11, wherein a second heat conductive member that contacts each of the first heat conductive member and the back chassis is disposed.   12. The liquid crystal display device according to claim 11, wherein the first heat conducting member is divided.   12. The liquid crystal display device according to claim 11, wherein the back chassis is formed with air guiding means for guiding outside air to a central portion of the first heat conducting member.

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