JP2010129359A - Backlight unit and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a backlight unit for a liquid crystal display device which clearly classifies a light amount distribution on the backlight unit according to a region, and controls the temperature rise of a backlight substrate. <P>SOLUTION: The backlight unit 6 includes: a backlight substrate 8; and two or more LEDs 10 arranged on one surface of the backlight substrate 8, wherein heat dissipation plates 14 containing metal arranged between two or more LEDs 10 are attached to the backlight substrate 8. Thereby, heat generated in the two or more LEDs 10 can be radiated through the heat dissipation plates 14 more efficiently than a conventional one. Moreover, since two or more LEDs 10 and the heat dissipation plates 14 are arranged on the same surface of the backlight substrate 8, the backlight unit 6 can be made thin. Namely, the temperature rise can be controlled without increasing the thickness. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a backlight unit built in a liquid crystal display device or the like. The present invention also relates to a liquid crystal display device incorporating a backlight unit.

  In recent years, liquid crystal display devices are often used for televisions, monitors, and the like due to the trend toward thinning and high quality image display devices. Since the liquid crystal panel of the liquid crystal display device does not emit light by itself, a backlight unit (hereinafter also referred to as BLU) is required. As a light source used for BLU, a cold cathode fluorescent lamp (CCFL) has been mainly used. However, BLU using CCFL has problems such as environmental pollution by mercury, slow response speed, and difficulty in partial driving. For this reason, recently, the light source used for BLU tends to be shifted from CCFL to LED (light emitting diode).

  Generally, BLUs using LEDs are classified into direct type BLU (direct type) and edge type BLU (side type). In the direct type BLU, a plurality of LEDs are arranged in a planar manner on the surface of the substrate facing the liquid crystal panel, and light emitted from these LEDs is directly applied to the back surface of the liquid crystal panel. On the other hand, in the edge type BLU, LEDs are linearly arranged on the side surface of the light guide plate, and light emitted from these LEDs is irradiated from the upper surface of the light guide plate to the back surface of the liquid crystal panel.

  The direct type BLU is often driven by a partial drive method in order to display a clearer image. Typical partial driving methods for the direct type LED include local dimming and impulsive.

  In the local dimming driving method, the liquid crystal panel is divided into a plurality of areas, and the light amount of the LED arranged on the backlight substrate is individually determined for each area according to the luminance in each area of the image to be displayed. This is a drive system that adjusts. As a result, a portion to be displayed brightly can be displayed brighter, and a portion to be displayed dark can be displayed darker. On the other hand, the impulsive driving method is a driving method in which the opening and closing of the liquid crystal shutter in the liquid crystal panel and the lighting of the light source are temporally synchronized by sequentially lighting a plurality of light source regions arranged vertically.

  A liquid crystal display device including a direct type BLU includes, for example, a liquid crystal panel, a BLU, and a large number of optical sheets disposed therebetween. The BLU is further arranged on the backlight substrate and the backlight substrate. A plurality of red, green, and blue LEDs. The backlight substrate is provided with a circuit unit for controlling and driving the LEDs.

  FIG. 7 is a diagram for explaining a partial (region-specific) driving method such as local dimming or impulsive. 7A shows the light / dark distribution of the image to be displayed on the liquid crystal panel, FIG. 7B shows the LED lighting state of the BLU corresponding to FIG. 7A, and FIG. It is a figure which shows light quantity distribution on BLU. As shown in FIG. 7A, when the image 31 to be displayed on the liquid crystal panel shows a light / dark distribution (or image signal distribution) divided into dark regions 31a and 31d and bright regions 31b and 31c, By driving the LEDs on the backlight substrate 32 for each region as shown in FIG. 7B, the displayed image can be made clearer. That is, only the LED groups 32b and 32c immediately below the bright areas 31b and 31c are turned on, and the LED groups 32a and 32d immediately below the dark areas 31a and 31d are turned off, thereby making the bright areas 31b and 31c brighter. The dark areas 31a and 31d can be displayed darker.

  However, even in such a partial drive method, there is a problem in that the light distribution on the BLU is not clearly divided for each region, and the effect of partial drive cannot be obtained sufficiently. Specifically, as shown in FIG. 7C, an LED group 32b is provided between the low luminance region 33c corresponding to the dark regions 31a and 31d and the high luminance region 33a corresponding to the bright regions 31b and 31c. And the light emitted from 32c leaks, and the intermediate region 33b in which the luminance changes gradually is formed. That is, even if only the LED groups 32b and 32c immediately below the bright areas 31b and 31c are lit, the low-luminance area and the high-luminance area cannot be clearly distinguished as the light quantity distribution on the BLU 33.

Patent Document 1 discloses a technique in which a partition wall is arranged between LEDs provided on a backlight substrate in order to clearly divide the light amount distribution on the direct type BLU for each region. That is, by arranging a partition that reflects or absorbs light between the LEDs, the light amount distribution on the BLU is clearly divided for each light source region.
JP 2007-286627 A (Publication date: November 1, 2007)

  However, the technique described in Patent Document 1 has a problem in that the LED deteriorates due to the temperature rise of the backlight substrate. In addition, there is a problem that color unevenness occurs because the temperature rise of the backlight substrate is not spatially uniform. Furthermore, in order to avoid such a problem, if a heat dissipation mechanism is provided on the back surface of the backlight substrate, a new problem of increasing the thickness of the backlight unit is caused.

  The present invention has been made in view of the above problems, and an object of the present invention is a backlight unit capable of classifying the light amount distribution for each region, and suppressing the temperature rise without increasing the thickness. Is to provide.

  In order to solve the above problems, a backlight unit according to the present invention is a backlight unit including a substrate and a plurality of light sources arranged on one surface of the substrate, and the substrate includes: A heat dissipation plate including metal disposed between the plurality of light sources is attached.

  Since the said heat sink contains a metal, heat conductivity is high compared with the simple light-shielding plate which does not contain a metal. Therefore, according to said structure, the heat | fever generate | occur | produced with said several light source can be thermally radiated more efficiently than the past through the said heat sink. And according to said structure, since the said several light source and the said heat sink are arrange | positioned on the same surface of the said board | substrate, a backlight unit can be made thin. That is, there is an effect of suppressing the temperature rise without increasing the thickness.

  It is preferable that the said heat sink of the backlight unit which concerns on this invention is formed with the metal.

  According to said structure, since the heat conductivity of the said heat sink further improves, there exists an effect that the heat dissipation effect can be heightened further.

  The heat sink of the backlight unit according to the present invention is preferably surface-coated with a metal.

  According to said structure, there exists the further effect that a backlight unit can be reduced in weight, without sacrificing a thermal radiation effect by comprising the inside of a heat sink with a material lighter than a metal.

  In addition, as a metal contained in the said heat sink, copper, aluminum, etc. can be mentioned, for example. However, any metal may be used as long as it has a higher thermal conductivity than the substrate, and the present invention is not limited to these.

  It is preferable that the board | substrate of the backlight unit which concerns on this invention is a rectangle, and the said heat sink is arrange | positioned in parallel with the short side or long side of the said board | substrate.

  According to said structure, since the said heat sink is arrange | positioned in parallel with the short side or long side of the said board | substrate, the further effect that it is especially useful when driving the said light source by an impulsive drive system is produced. Play.

  In the backlight unit according to the present invention, it is preferable that the plurality of heat sinks parallel to the short sides of the substrate and the plurality of heat sinks parallel to the long sides of the substrate are arranged in a matrix. .

  According to said structure, since the said heat sink is arrange | positioned in the matrix form on the said board | substrate, there exists the further effect that it is especially useful when driving the said light source by a local dimming drive system.

  It is preferable that the radiator plate of the backlight unit according to the present invention is disposed only in one of two regions obtained by dividing the substrate along a straight line parallel to the long side. .

  The backlight unit is usually used such that the short side of the substrate is substantially perpendicular to the floor and the long side of the substrate is substantially parallel to the floor. At this time, when two regions obtained by dividing the substrate by a straight line parallel to the long side thereof are compared, the temperature of the ceiling side region is higher than that of the floor side region. By the way, according to said structure, when the two area | regions obtained by dividing | segmenting the said board | substrate by the straight line parallel to the long side are compared, the area | region where the heat sink is arrange | positioned is not arrange | positioned. Higher heat dissipation effect than the area. Therefore, when the backlight unit is arranged so that the region where the heat radiating plate is arranged is on the ceiling side, the temperature of the substrate can be made substantially uniform. That is, there is a further effect of reducing color unevenness due to temperature rise.

  It is preferable that the said heat sink of the backlight unit which concerns on this invention is arrange | positioned only at the outer periphery of the said board | substrate.

  According to said structure, since the said heat sink is arrange | positioned only at the outer periphery of the said board | substrate, there exists the further effect that the said heat sink can be arrange | positioned efficiently.

  It is preferable that a heat pipe is attached to the heat radiating plate of the backlight unit according to the present invention.

  According to said structure, since the heat pipe is attached to the said heat sink, there exists the further effect that a higher heat dissipation effect is acquired rather than the case where only a heat sink is arrange | positioned.

  It is preferable that the heat radiating part of the heat pipe of the backlight unit according to the present invention is disposed outside the substrate.

  According to said structure, since the said thermal radiation part is arrange | positioned outside the said board | substrate, heat can be released outside the said board | substrate. Therefore, there is an additional effect that heat in the substrate can be efficiently released.

  It is preferable that a fin is provided in the heat dissipation part of the backlight unit according to the present invention.

  According to said structure, since the said heat radiating part is provided with the fin, the surface area of the said heat radiating part becomes large. Therefore, there is an additional effect that the heat in the substrate can be released more efficiently.

  The heat sink of the backlight unit according to the present invention preferably has a visible light reflectance of 50% or less.

  According to said structure, it can prevent that the reflected light radiated | emitted from a certain light source and reflected by the heat sink surrounding the light source leaks outside the area | region enclosed by those heat sinks. Therefore, there is an additional effect that the light amount distribution on the backlight unit can be clearly divided for each region partitioned by the heat sink.

  The width of the backlight unit according to the present invention in the vertical direction with respect to the substrate of the radiator plate is preferably 5 mm or more.

  According to said structure, it can prevent that the light radiated | emitted from a certain light source leaks outside the area | region enclosed by those heat sinks exceeding the heat sink surrounding the light source. Therefore, there is an additional effect that the light amount distribution on the backlight unit can be clearly divided for each region partitioned by the heat sink.

  A liquid crystal display device having the backlight unit, wherein the liquid crystal display device emits light to the liquid crystal panel by driving the plurality of light sources for each region divided by the heat sink. Included in the category.

  As described above, the backlight unit according to the present invention is a backlight unit including a substrate and a plurality of light sources arranged on one surface of the substrate, and the substrate includes the plurality of light sources. A heat sink including metal, which is disposed between the light sources, is attached. Therefore, the heat generated by the plurality of light sources can be radiated more efficiently than before through the heat radiating plate. And according to said structure, since the said several light source and the said heat sink are arrange | positioned on the same surface of the said board | substrate, a backlight unit can be made thin. That is, the temperature rise can be suppressed without increasing the thickness.

  An embodiment of the present invention will be described below with reference to the drawings.

(Configuration of the liquid crystal display device 1)
First, the configuration of the liquid crystal display device 1 according to the present embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view showing the configuration of the liquid crystal display device 1. The liquid crystal display device 1 includes a liquid crystal panel 2, a backlight unit 6, and an optical sheet 4 disposed between the liquid crystal panel 2 and the backlight unit 6. The backlight unit 6 is a direct-type BLU, and is disposed on the side opposite to the display surface side of the liquid crystal panel 2, and emits light to the back surface of the liquid crystal panel 2. The backlight unit 6 further includes a backlight substrate 8, a plurality of LEDs (light emitting diodes) 10 arranged on the backlight substrate 8, a circuit unit 12 including a control unit that controls the LEDs 10 and a driving unit that drives the LEDs 10, And a heat radiating plate 14 including a metal disposed between the plurality of LEDs 10 on the backlight substrate 8. The heat sink 14 is formed substantially perpendicular to the backlight substrate 8 and is formed of a metal such as Cu or Al. In addition, the heat sink 14 does not need to be formed only with the metal, and should just contain the metal. For example, the surface may be coated with a metal such as Cu or Al.

  Since the heat radiating plate 14 includes metal, the heat on the surface of the backlight substrate 8 can be dissipated from the backlight substrate 8 into the atmosphere in the liquid crystal display device 1. The heat dissipated in the atmosphere moves upward in the vertical direction by convection, and is dissipated outside the liquid crystal display device 1 through a slit (not shown) formed in the outer wall of the liquid crystal display device 1. Thus, by suppressing the temperature rise of the backlight substrate 8 by the heat radiating plate 14, problems due to the temperature rise such as the deterioration of the LED 10 can be suppressed. Moreover, since it becomes unnecessary to arrange | position the member which suppresses a temperature rise on the back surface of the backlight board | substrate 8, it can suppress that the backlight unit 6 becomes thick here.

  The backlight substrate 8 is divided into a plurality of light source regions, and each light source region includes at least one red, green, and blue LED 10. By using the red, green, and blue LEDs 10, the backlight unit 6 can emit white light having excellent color reproducibility. Each light source region may include at least one white LED 10 obtained by using a blue LED chip and a yellow phosphor.

  Each light source region can be partially driven by each light source region by controlling the circuit unit 12 so as to implement a local dimming driving method or an impulsive driving method. In the local dimming driving method, the luminance of each light source region is controlled by controlling and driving the LED 10 according to the peak value of the gray level (separated luminance value) of each light source region. Specifically, the control unit included in the circuit unit 12 is configured so that at least a part of the light source region has a luminance different from that of the other light source regions in accordance with the gray level peak value in each light source region. Operation is controlled and the said drive part drives LED10 by control of the said control part. In the impulsive drive system, a plurality of light source regions arranged in parallel with the short side or the long side on the rectangular backlight substrate are sequentially turned on.

(Effect of light quantity distribution by heat sink 14)
The heat radiating plate 14 is disposed at the boundary between the light source regions that are partially driven. Since the heat sink 14 absorbs light emitted from the LEDs 10 in each light source region, the light is prevented from leaking out from the emitted light source region. That is, by providing the heat radiating plate 14, the light quantity distribution on the backlight unit 6 can be more clearly classified for each light source region.

  It is preferable that the heat sink 14 has a low reflectance in the visible light region. This is because the lower the reflectance of the heat sink 14, the more the reflected light emitted from a certain LED 10 and reflected by the heat sink 14 surrounding the LED 10 leaks to the outside of the area surrounded by the heat sink 14. This is because it can be prevented. Therefore, the light quantity distribution on the backlight unit 6 can be more clearly divided for each region partitioned by the heat sink 14. Specifically, the reflectance of the heat sink 14 is preferably 50% or less in the visible light region of 360 nm to 830 nm.

  Moreover, it is preferable that the width | variety of the orthogonal | vertical direction with respect to the backlight board | substrate 8 of the heat sink 14 is longer. This is because, as the vertical width of the heat sink 14 increases, the light emitted from a certain LED 10 leaks beyond the heat sink 14 surrounding the light source to the outside of the region surrounded by the heat sink 14. Can be prevented. Therefore, the light quantity distribution on the backlight unit 6 can be more clearly divided for each region partitioned by the heat sink 14. Specifically, the vertical width of the heat sink 14 with respect to the backlight substrate 8 is preferably 5 mm or more, and more preferably 10 mm or more.

  This will be described with reference to FIG. FIG. 2 is a graph showing the light amount distribution on the backlight unit 6 with respect to the height of the heat sink 14. The dotted lines B and B ′ shown in FIG. 2 are the positions of the heat radiating plate 14 on the backlight substrate 8, and C is the position of the lighted light source region. As shown in FIG. 2, the higher the heat sink 14 is, the higher the luminance in the vicinity of the lighted light source region (in the center of the graph) and the lower the luminance in the vicinity of the unlighted light source region (both ends of the graph). Become. That is, as the height of the heat radiating plate 14 is increased, the brightness is more clearly divided.

  Further, the light amount distribution on the backlight unit 6 is also affected by the width in the direction perpendicular to the backlight substrate 8 between the backlight substrate 8 and the optical sheet 4 as indicated by an arrow A in FIG. In other words, the width of the heat sink 14 in the vertical direction with respect to the backlight substrate 8 is longer and the width in the vertical direction with respect to the backlight substrate 8 between the backlight substrate 8 and the optical sheet 4 is shorter, that is, FIG. The shorter the distance indicated by the arrow A ′ is, the clearer the light quantity distribution on the backlight unit 6 becomes. Note that the length of the heat radiating plate 14 does not have to be taken into consideration when the purpose is to dissipate only the backlight substrate 8 and not the light quantity distribution. For example, the heat sink 14 may be 5 mm or less.

(Arrangement of heat sink 14)
Next, the arrangement | positioning aspect of the heat sink 14 on the backlight board | substrate 8 is demonstrated with reference to FIG. FIG. 3 is a plan view of the backlight substrate 8 on which the heat sink 14 is disposed. As shown in FIGS. 3A and 3B, the heat dissipation plate 14 is disposed on the rectangular backlight substrate 8 in parallel with the short side or the long side of the backlight substrate 8. Such an arrangement mode is particularly useful when the LED 10 is driven by an impulsive driving method.

  Further, as shown in FIGS. 3C and 3D, the heat sink 14 may be arranged in a matrix. Such an arrangement mode is particularly useful when the LED 10 is driven by a local dimming driving method. Further, as shown in FIG. 3E, the heat radiating plate 14 may be disposed only on the outer periphery of the backlight substrate 8.

  Here, the temperature difference in the backlight substrate 8 will be described with reference to FIG. FIG. 4A shows the distribution of the back surface temperature in the backlight substrate 8 when the liquid crystal display device 1 is finally used as a product in the vertical direction, and FIG. 4B shows the backlight substrate. 8 is a graph showing the distribution of the back surface temperature of FIG. In FIG. 4A, X represents the horizontal direction, and Z represents the vertical direction. Due to the convection of air around the backlight substrate 8, the temperature of the upper portion of the backlight substrate 8 becomes higher than the temperature of the lower portion of the backlight substrate 8 as shown in FIG.

  Further, when a heat conducting member is provided in the backlight substrate 8, as shown by a dotted line in FIG. 4B, an effect of making the substrate temperature uniform can be obtained, but it does not contribute to a decrease in the average substrate temperature. On the other hand, when the heat radiating plate 14 is provided on the backlight substrate 8, as shown by a chain line in FIG. 4B, the effects of making the substrate temperature uniform and lowering the average substrate temperature are obtained.

  From the above, when the heat radiating plate 14 is arranged in the upper part of the backlight substrate 8 in the vertical direction, the upper region of the backlight substrate 8 where the temperature becomes high (the backlight substrate 8 is divided by a straight line parallel to the long side thereof. Thus, it is preferable to dispose the heat sink 14 so that the tip protrudes into a region on the ceiling side obtained in this manner and a region occupying 1/3 or more of the backlight substrate 8. This configuration is shown in FIGS. 3 (f) and 3 (g). The arrows D and D ′ in FIGS. 3 (f) and 3 (g) indicate the vertical height when the backlight substrate 8 is used, and the arrows E and E ′ indicate the upper region of the backlight substrate 8. Yes. As shown in FIGS. 3 (f) and 3 (g), the heat sink 14 is provided only in one of the two regions obtained by dividing the backlight substrate 8 by a straight line parallel to the long side. Has been placed.

  Next, the case where the heat pipe 20 is attached to the heat sink 14 will be described with reference to FIG.

  First, a basic configuration of the heat pipe 20 will be described with reference to FIG. The heat pipe 20 illustrated in FIG. 5A includes a heat input portion 21, a heat radiating portion 22, and a connection portion 23 that connects the heat input portion 21 and the heat radiating portion 22. When the heat pipe 20 is arranged in the horizontal direction when the backlight substrate 8 is used, the heat radiating part 22 is arranged so as to be higher than the heat input part 21 in the vertical direction or at the same height. Further, the heat radiating portion 22 is disposed outside the backlight substrate 8. For this reason, heat can be released outside the backlight substrate 8. Further, as shown in FIG. 5B, the heat radiating portion 22 may be provided with fins 24. By providing the fins 24, the surface area of the heat radiating portion 22 is increased. Therefore, the heat in the backlight substrate 8 can be released more efficiently.

  Next, the arrangement | positioning aspect of the heat pipe 20 on the backlight board | substrate 8 is demonstrated with reference to FIG. FIG. 6 is a plan view of the backlight substrate 8 on which the heat pipe 20 is arranged. FIGS. 6A to 6G are plan views of the backlight substrate 8 in which the heat pipe 20 is attached to the heat radiating plate 14 shown in FIGS. 3A to 3G. As shown in FIGS. 6A and 6F, when the heat pipe 20 is arranged parallel to the vertical direction when the liquid crystal display device 1 is used, the heat input portion 21 is placed inside the backlight substrate 8 and the heat radiating portion. 22 is disposed outside the backlight substrate 8 in the vertical direction. Further, as shown in FIGS. 6B to 6E and 6G, when the heat pipe 20 is arranged in the horizontal direction when the liquid crystal display device 1 is used, as shown in FIG. The heat input portions 21 of the two heat pipes 20 are connected inside the backlight substrate 8, and the heat radiating portion 22 is arranged outside the backlight substrate 8. Further, as shown in FIGS. 6C to 6E, a heat pipe 20 is attached to the horizontal heat radiating plate 14 when the liquid crystal display device 1 is used, and only the heat radiating plate 14 is arranged in the vertical direction. Good. In addition, arrows F and F ′ shown in FIGS. 6 (f) and 6 (g) indicate vertical heights when the backlight substrate 8 is used, and arrows G and G ′ indicate upper regions of the backlight substrate 8. Is shown. As shown in FIGS. 6 (f) and 6 (g), the heat pipe 20 is only in one of the two regions obtained by dividing the backlight substrate 8 by a straight line parallel to the long side. Has been placed.

[Additional Notes]
The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

The present invention can also be expressed as follows, for example.
1. In a direct type backlight unit that is disposed at the bottom of the liquid crystal panel and emits light from the rear surface of the liquid crystal panel, the backlight unit has a plurality of light source regions formed on the substrate, and the LED light source unit includes at least one LED, A backlight unit for a liquid crystal display device, wherein a heat sink is formed on a mounting surface formed between the light source regions of the LED light source unit formed on the substrate.

  The backlight unit according to 2.1, wherein the heat sink is formed of a material satisfying a reflectance of 80% or more in a visible light region: 360 nm to 830 nm.

  The backlight unit using Cu (copper) or Al (aluminum) as the material of the heat sink described in 3.1.

  The backlight unit used by coating the surface of Cu (copper) or Al (aluminum) as the heat sink material described in 4.1.

  A backlight unit in which the height of the heat sink according to 5.1 from the substrate surface is 5 mm or less.

  The arrangement of the heat sink described in 6.1 is a backlight unit that extends horizontally or vertically on the surface substrate.

  The arrangement of the heat sink described in 7.1 is a backlight unit arranged on a matrix on a surface substrate.

  The arrangement of the heat sink described in 8.1 is a backlight unit that extends horizontally or vertically in the upper half on the surface substrate.

  The heat sink described in 9.1 is a backlight unit arranged on the outermost periphery of the substrate on the front substrate.

  A backlight unit using a heat pipe for the heat sink according to 10.1.

  The arrangement of the heat pipe described in 11.10 is a backlight unit that extends in the horizontal or vertical direction on the surface substrate and installs a heat dissipation (pseudo-constriction) portion outside the backlight unit.

  The arrangement of the heat pipe described in 12.10 is a backlight unit in which a heat connection portion is extended in a horizontal or vertical direction on a surface substrate, and a heat sink (fin) is installed outside the backlight unit.

  13. In a direct type backlight unit that is disposed at the bottom of the liquid crystal panel and emits light from the rear surface of the liquid crystal panel, the backlight unit has a plurality of light source regions formed on the substrate, and the LED light source unit includes at least one LED, A backlight unit that forms a heat sink as a material on a light shielding wall surrounding one or more LEDs on a mounting surface formed between the light source regions of the LED light source unit formed on the substrate.

  A backlight unit using a light shielding wall material described in 14.13 having a light reflectance of 50% or less.

  A backlight unit in which the height of the heat sink according to 15.13 from the substrate surface is 10 mm or more.

  The backlight unit of the present invention can be widely applied to general backlight units, and in particular, can be applied to backlight units for liquid crystal display devices.

1, showing an embodiment of the present invention, is a cross-sectional view illustrating a configuration of a liquid crystal display device. FIG. FIG. 4 is a graph showing an embodiment of the present invention and showing a light amount distribution on a backlight unit with respect to a height of a heat sink. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1, showing an embodiment of the present invention, is a plan view showing an arrangement mode of a heat sink on a backlight substrate. FIG. 3 is a diagram illustrating an embodiment of the present invention and explaining a temperature difference in a backlight substrate. (A) is a figure which shows the temperature difference of the air in a backlight board | substrate perpendicular | vertical direction, (b) is a figure which shows the board | substrate temperature of a backlight. 1 is a cross-sectional view illustrating a configuration of a heat pipe according to an embodiment of the present invention. (A) is sectional drawing which shows the heat pipe which is not provided with the fin, (b) is sectional drawing which shows the heat pipe provided with the fin. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an embodiment of the present invention, in which (a) to (g) are plan views illustrating an arrangement mode of heat pipes on a backlight substrate, and (h) is a diagram illustrating connection of heat pipes. FIG. 2A is a diagram illustrating a prior art, in which FIG. 1A is a diagram illustrating a light / dark distribution of an image to be displayed on a liquid crystal panel, FIG. 2B is a diagram illustrating a lighting state of an LED, and FIG. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2 Liquid crystal panel 4 Optical sheet 6 Backlight unit 8 Backlight board 10 LED
12 circuit part 14 heat sink 20 heat pipe 21 heat input part 22 heat radiating part 23 connection part 24 fin

Claims (12)

A backlight unit comprising a substrate and a plurality of light sources arranged on one surface of the substrate,
The substrate is attached with a heat sink including metal, disposed between the plurality of light sources.
Backlight unit characterized by that. The heat sink is made of metal.
The backlight unit according to claim 1. The heat sink is surface-coated with metal,
The backlight unit according to claim 1. The metal is copper or aluminum.
The backlight unit according to any one of claims 1 to 3, wherein the backlight unit is provided. The substrate is rectangular,
The heat sink is arranged in parallel with the short side or the long side of the substrate,
The backlight unit according to any one of claims 1 to 4, wherein the backlight unit is provided. The plurality of heat sinks parallel to the short sides of the substrate and the plurality of heat sinks parallel to the long sides of the substrate are arranged in a matrix.
The backlight unit according to claim 5. The heat radiating plate is disposed only in one of two regions obtained by dividing the substrate by a straight line parallel to its long side,
The backlight unit according to claim 5. The heat sink is disposed only on the outer periphery of the substrate.
The backlight unit according to claim 5. A heat pipe is attached to the heat sink,
The backlight unit according to claim 1, wherein the backlight unit is a backlight unit. The heat dissipating part of the heat pipe is disposed outside the substrate,
The backlight unit according to claim 9. The heat dissipation part is provided with fins,
The backlight unit according to claim 10.   A liquid crystal display device comprising the backlight unit according to any one of claims 1 to 11, wherein the liquid crystal panel is driven by driving the plurality of light sources for each region divided by the heat sink. A liquid crystal display device characterized by irradiating light.

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