WO2013008740A1 - Backlight, and liquid crystal display device - Google Patents

Backlight, and liquid crystal display device Download PDF

Info

Publication number
WO2013008740A1
WO2013008740A1 PCT/JP2012/067312 JP2012067312W WO2013008740A1 WO 2013008740 A1 WO2013008740 A1 WO 2013008740A1 JP 2012067312 W JP2012067312 W JP 2012067312W WO 2013008740 A1 WO2013008740 A1 WO 2013008740A1
Authority
WO
WIPO (PCT)
Prior art keywords
backlight
sheet
heat
light
light source
Prior art date
Application number
PCT/JP2012/067312
Other languages
French (fr)
Japanese (ja)
Inventor
達朗 黒田
Original Assignee
シャープ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by シャープ株式会社 filed Critical シャープ株式会社
Publication of WO2013008740A1 publication Critical patent/WO2013008740A1/en

Links

Images

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0081—Mechanical or electrical aspects of the light guide and light source in the lighting device peculiar to the adaptation to planar light guides, e.g. concerning packaging
    • G02B6/0085—Means for removing heat created by the light source from the package
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133615—Edge-illuminating devices, i.e. illuminating from the side
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0081—Mechanical or electrical aspects of the light guide and light source in the lighting device peculiar to the adaptation to planar light guides, e.g. concerning packaging
    • G02B6/0086—Positioning aspects
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133628—Illuminating devices with cooling means

Definitions

  • the present invention relates to an edge light type backlight using an LED as a light source and a liquid crystal display device using the backlight.
  • the liquid crystal display device includes a liquid crystal panel unit and a backlight disposed on the back surface of the liquid crystal panel unit, and the liquid crystal panel unit adjusts a light transmittance (amount of transmission) from the backlight, An image is displayed on the front surface of the liquid crystal panel unit.
  • the backlight there is a light guide plate method (edge light method) in which light is incident from the side surface of the light guide plate. Since the edge light type backlight has a structure in which light is incident from the side surface of the light guide plate, it is difficult to emit large planar light with a uniform luminance distribution. Therefore, an edge light type backlight is often used for a small liquid crystal display device such as a notebook PC monitor or a gaming machine monitor.
  • the edge-light type backlight has a light source unit in which a plurality of LEDs as light sources are arranged side by side, and light emitted from the light source unit is received from the light receiving surface on the side surface, and is more planar than the light exit surface of one main surface
  • a light guide plate that emits light, an optical sheet that is disposed adjacent to the light exit surface of the light guide plate, and a reflective sheet that is disposed adjacent to a surface opposite to the light exit surface of the light guide plate are provided. These members are arranged inside the backlight chassis.
  • the reflection sheet is positioned and fixed at the four corners with screws, pins or the like.
  • the four corners are fixed, so that the amount of deformation cannot be absorbed, and wrinkles and deflection may occur.
  • a heat spreader is attached to a portion of the backlight chassis adjacent to the light source unit. The heat spreader radiates heat generated from the light source unit to the outside.
  • the heat spreader alone cannot sufficiently release heat from the light source unit, and heat is transmitted to the reflection sheet disposed inside the backlight chassis.
  • the reflection sheet is deformed (expanded) by the heat, and undulations such as wrinkles and deflection occur. Due to this undulation, the direction of the light reflected by the reflection sheet is disturbed, which may cause uneven brightness of the planar light.
  • a heat transfer sheet formed of a material having high thermal conductivity such as graphite Has been proposed which is arranged on the back side of the reflection sheet. Since the heat transfer sheet assists in releasing the heat of the reflection sheet to the outside, it is possible to suppress the reflection sheet from being deformed by heat.
  • the heat dissipation sheet is disposed on the back surface of the reflection sheet, the heat dissipation sheet is formed thin in order to prevent unevenness from being formed on the reflection sheet. Moreover, the said heat radiating sheet is formed in the adhesive sheet shape, and can be easily affixed on the said backlight chassis.
  • the heat-dissipating sheet has the property of being easily torn due to its material, thinness, etc., it is difficult to work in a state where tension is applied, and it is difficult to stick it so that wrinkles do not occur, and advanced technology is required. Cost.
  • wrinkles often form an air layer (so-called air pocket) between the heat dissipation sheet and the heat spreader. Since air has a lower thermal conductivity than the heat dissipation sheet, heat conduction from the LED substrate to the heat spreader or from the reflective sheet to the heat spreader decreases due to the air accumulation.
  • an object of the present invention is to provide a backlight capable of suppressing the deformation of the reflection sheet due to heat from a light source or the like and suppressing the occurrence of luminance unevenness of the emitted planar light.
  • the present invention provides a light source unit that is arranged on a side surface of a light guide plate and that has a plurality of light sources arranged side by side, a reflective sheet that reflects at least light in the visible light region, the light source unit, and the light guide plate. And a backlight chassis in which the reflection sheet is disposed, a heat spreader that is attached to a portion of the backlight chassis in which the light source unit is disposed, and dissipates heat from the light source unit, an upper portion of the heat spreader, and the backlight
  • a backlight comprising: a heat dissipating sheet disposed on an upper portion of a bottom portion of the chassis adjacent to the light source unit and having a plurality of slits.
  • the air reservoir is formed between the heat radiation sheet and the heat spreader and / or the bottom, it is possible to suppress the reflection sheet from rising and disturbing the direction of the reflected light.
  • the plurality of slits may be arranged side by side along the light source unit.
  • the plurality of slits may be cuts formed inwardly from the edge of the heat dissipation sheet.
  • the tip of each of the plurality of slits may be connected to a through hole having a shape formed by an obtuse angle or a curve.
  • the heat dissipation sheet has a plurality of slits formed on each of the opposing sides, and the leading ends of the slits on the opposing sides are adjacent to the leading ends of the slits formed on the opposing sides. It may be formed.
  • the heat radiating sheet may have a plurality of through holes formed at a further portion of the ends of the plurality of slits.
  • Examples of the apparatus using the above-described backlight include a liquid crystal display device including a liquid crystal panel unit disposed on the entire surface side of the backlight.
  • the present invention it is possible to suppress the formation of air pockets when the heat dissipation sheet is attached, and it is possible to efficiently dissipate heat generated by the LED, which is a light source, with the heat dissipation sheet.
  • FIG. 1 It is a disassembled perspective view of an example of the liquid crystal display device provided with the backlight concerning this invention. It is sectional drawing of the liquid crystal display device shown in FIG. It is a figure which shows the backlight with which the thermal radiation sheet was attached. It is an enlarged view of a thermal radiation sheet. It is an enlarged view of the thermal radiation sheet
  • FIG. 1 is an exploded perspective view of an example of a liquid crystal display device having a backlight according to the present invention
  • FIG. 2 is a cross-sectional view of the liquid crystal display device shown in FIG.
  • the liquid crystal display device A includes a backlight 1 and a liquid crystal panel unit 6.
  • the liquid crystal panel unit 6 is disposed on the front side (observer side) of the backlight 1, and the liquid crystal panel unit 6 is held by a metal bezel 7 having an opening window 70 in the center. It has been.
  • the upper side of the drawing is the front side, that is, the observer side, and the lower side is the back side. Further, in the following description, the description will be given with reference to the front surface and the back surface in the state of FIG. 1 or 2 unless otherwise specified.
  • the backlight 1 is an illumination device that irradiates the liquid crystal panel unit 6 with planar light.
  • the backlight 1 includes a flat light guide plate 2, a light source unit 3 that emits light toward a light receiving surface 22 formed on a side surface of the light guide plate 2, and an optical sheet 4 that is disposed in the vicinity of the light guide plate 2.
  • the backlight 1 includes a backlight chassis 10, and at least the light guide plate 2, the light source unit 3, and the optical sheet 4 are disposed inside the backlight chassis 10.
  • the detail of the backlight 1 which is the principal part of this invention is mentioned later.
  • the liquid crystal panel unit 6 includes a liquid crystal panel 61 in which liquid crystal is sealed, and a polarizing plate 62 attached to the front surface (observer side) and the back surface (backlight 1 side) of the liquid crystal panel 61.
  • the liquid crystal panel 61 includes an array substrate 611, a counter substrate 612 arranged to face the array substrate 611, and liquid crystal filled between the array substrate and the counter substrate. It is out.
  • the array substrate 611 is provided with a source wiring and a gate wiring orthogonal to each other, a switching element (for example, a thin film transistor) connected to the source wiring and the gate wiring, a pixel electrode connected to the switching element, an alignment film, and the like.
  • the counter substrate 612 is provided with a color filter in which colored portions of red, green, and blue (RGB) are arranged in a predetermined arrangement, a common electrode, an alignment film, and the like.
  • the array substrate 611 is formed so as to protrude from the counter substrate 612.
  • a circuit for driving the switching element is formed in the protruding portion, and the drive substrate 8 is connected via the flexible substrate 81.
  • the drive substrate 8 transmits a drive signal to the switching elements of the array substrate 611 via the flexible substrate 81.
  • a voltage is applied between the pixel electrode of the array substrate 611 and the counter electrode k of the counter substrate 612 in each pixel of the liquid crystal panel 61.
  • the light transmission degree in each pixel is changed. As a result, an image is displayed in the image display area on the viewer side of the liquid crystal panel 61.
  • the bezel 7 is a metal frame, and has a shape that covers the front edge of the liquid crystal panel unit 6. As shown in FIG. 2, the bezel 7 includes a rectangular opening window 70 formed so that the image display area of the liquid crystal panel unit 6 is not hidden, a presser 71 that presses the liquid crystal panel unit 6 from the front side, and a presser A cover portion 72 that protrudes from the edge portion of 71 to the back side and covers the edge portion of the liquid crystal panel unit 6 and the backlight 1 is provided.
  • the bezel 7 is grounded and shields the liquid crystal panel unit 6 and the backlight 1.
  • the drive substrate 8 is attached to a chassis case 102 described later provided in the backlight 1.
  • a reflective sheet 104 is disposed inside the backlight chassis 10. Further, the edge side of the front side of the optical sheet 4 (liquid crystal panel unit side) is held by the chassis case 102.
  • the backlight chassis 10 is a box-shaped member whose front side (liquid crystal panel unit side) is open, and has a bottom 100 that is rectangular in plan view, and a side wall that protrudes from the bottom 100. 101.
  • the backlight chassis 10 can also be referred to as a frame member having a bottom 100.
  • the light source unit 3 is fixed to the long side of the bottom 100 of the backlight chassis 10, and a heat spreader 103 for radiating heat from the light source unit 3 is attached.
  • the heat spreader 103 is formed with a wall body integrated with the side wall portion 101, and the light source unit 3 is fixed to the wall body.
  • the heat spreader 103 is a member for transferring the heat emitted from the light source unit 3 and releasing the heat to the outside, and a material having a higher thermal conductivity than the backlight chassis 10 (for example, a metal such as aluminum or stainless steel). It is formed with. Between the heat spreader 103 and the reflection sheet 104, a heat dissipation sheet 5 for efficiently transferring the heat transmitted from the light source unit 3 to the reflection sheet 104 to the heat spreader 103 is disposed.
  • the light guide plate 2 is formed by forming a transparent resin such as polymethyl methacrylate (PMMA) or polycarbonate into a flat plate shape.
  • a transparent resin such as polymethyl methacrylate (PMMA) or polycarbonate
  • PMMA polymethyl methacrylate
  • polycarbonate polycarbonate
  • the light guide plate 2 is a flat plate member having a rectangular shape in plan view.
  • the main surface facing the liquid crystal panel unit 6 is configured as a light output surface 21, and the side surface in the short direction is configured as a light receiving surface 22 that receives light from the light source unit 3.
  • the light source unit 3 includes a long LED array substrate 30 disposed to face the light receiving surface 22, and a plurality (eight) of LEDs 31 (light sources) arranged linearly on the LED array substrate 30. ing.
  • the LEDs 31 are arranged at equal intervals, but may be an arrangement in which the intervals are partially changed.
  • the LED array substrate 30 is attached and fixed to the side wall portion 101 of the backlight chassis 10. At this time, the LED 31 faces the inside of the backlight 1, that is, the light receiving surface 22 of the light guide plate 2. Thereby, the light emitted from the LED 31 enters the light receiving surface 22.
  • the optical sheet 4 is emitted from the light exit surface 21 as an optical sheet member, a diffusion sheet 41 that diffuses the light emitted from the light exit surface 21 of the light guide plate 2, a brightness enhancement sheet (DBEF) 42 that improves brightness.
  • a prism sheet 43 is provided that aligns the direction of light, that is, changes the direction so that light entering obliquely faces the liquid crystal panel unit 6.
  • An optical sheet member having optical characteristics other than these may be used.
  • FIG. 3A is a view showing a backlight to which a heat dissipation sheet is attached
  • FIG. 3B is an enlarged view of the heat dissipation sheet.
  • the longitudinal direction of the backlight chassis 10 is the X direction
  • the short direction is the Y direction.
  • the X direction and the Y direction may be used similarly.
  • the light guide plate 2 and the optical sheet 4 are not shown.
  • the heat dissipation sheet 5 is attached so as to partially overlap the heat spreader 103. More specifically, the heat radiating sheet 5 is attached to a portion of the light source unit 3 where the LED 31 is disposed, and efficiently transmits heat generated from the LED 31 to the heat spreader 103.
  • the heat radiating sheet 5 is a thin film sheet containing a material having high thermal conductivity such as graphite, and one surface is an adhesive sheet formed on an adhesive surface.
  • the heat-dissipating sheet 5 containing graphite is easily damaged due to its nature, and it is difficult to rework (rework).
  • it is a thin film sheet, wrinkles are easily formed in the heat dissipation sheet 5 when it is attached to the backlight chassis 10.
  • a so-called air pocket that is wrinkled is easily formed. When the air pool is formed, heat conduction from the light source unit 3 to the heat spreader 103 or from the reflection sheet 104 to the heat spreader 103 is deteriorated.
  • FIG. 3B air pockets are suppressed by forming slits 51 in the heat dissipating sheet 5.
  • a method for suppressing air accumulation by the slit 51 will be described. It is difficult to attach the heat dissipating sheet 5 so as not to be wrinkled, requiring special tools and techniques. Therefore, the heat radiating sheet 5 is attached to the heat spreader 103 and the backlight chassis 10 on the assumption that a certain amount of wrinkles are formed.
  • the heat radiation sheet 5 is an adhesive sheet, and the air accumulated in the wrinkles can be moved to some extent by pressing the heat radiation sheet 5.
  • the slits 51 By forming the slits 51 at a predetermined interval, the air accumulated in the wrinkles can be pushed to the slits 51 and can be extracted from the slits 51.
  • the heat radiation sheet 5 and the heat spreader 103 can be brought into close contact with each other. From this, it can suppress that the heat conduction from the light source unit 3 to the heat spreader 103 falls by the air pocket.
  • most of the heat of the light source unit 3 is transmitted to the heat spreader via the heat radiating sheet 5, and the amount of heat conducted from the light source unit 3 to the reflection sheet 104 can be reduced.
  • the portion of the reflective sheet 104 close to the light source unit 3 is in contact with the heat radiating sheet 5, the heat transmitted from the light source unit 3 to the reflective sheet 104 is also efficiently released to the heat spreader 103 via the heat radiating sheet 5. .
  • the slit 51 is in a cut state extending inward from the edge of the heat radiating sheet 5, but is not limited thereto. 5 may be formed in both ends so as not to reach the edge. It is possible to widely employ a notch that can effectively remove the air entering the wrinkle generated when the heat radiation sheet 5 is attached. Further, the slit 51 may have a rectangular or triangular cutout shape instead of the cut shape. The same applies to the following embodiments.
  • FIG. 4 is an enlarged view of a heat dissipation sheet used in another example of the backlight according to the present invention.
  • the heat radiating sheet 5B has a circular through hole 52b, and the tip of the slit 51b is connected to the through hole 52b.
  • the through hole 52b at the tip of the slit 51b, it is possible to prevent stress from concentrating on the tip of the slit 51b.
  • it can suppress that the heat-radiation sheet 5B tears from the front-end
  • the heat dissipation sheet 5B includes the circular through-holes 52b.
  • the present invention is not limited to this, and when the heat dissipation sheet 5B is attached to the backlight chassis 10, corner portions where stress is likely to concentrate (for example, It is good also as a through-hole of a shape (for example, an ellipse, a hexagon, etc.) which does not have an acute angle, the front-end
  • FIG. 5 is an enlarged view of a heat dissipation sheet used in yet another example of the backlight according to the present invention.
  • the heat radiation sheet 5C has a certain width (for example, 5 cm, etc.)
  • an air pocket is easily formed in a portion other than the portion where the slit 51c is formed. Therefore, in order to effectively remove air formed in a portion other than the portion where the slit 51c is formed, a plurality of circular air vent holes 53c are formed in the heat dissipation sheet 5C.
  • the air vent holes 53c are formed in a line with a predetermined interval. Since the air vent hole 53c is formed in this way, the close contact between the heat radiation sheet 5C and the heat spreader 103 can be enhanced. It is possible to increase heat conduction.
  • the air vent hole 53c is a circular through hole, but is not limited thereto, and may be an ellipse, a polygon, or the like. Further, in the heat dissipation sheet 5C, the air vent holes 53c are arranged at equal intervals, but the present invention is not limited to this.
  • FIG. 6 is an enlarged view of a heat dissipation sheet used in another example of the backlight according to the present invention.
  • auxiliary slits 54d are also formed on the side opposite to the side where the slits 51d are formed.
  • the slits 51d and the auxiliary slits 54d are alternately formed so that the slits 51d and the auxiliary slits 54d are not connected.
  • the auxiliary slit 54d is formed in this way, in the heat radiating sheet 5D, air accumulated in wrinkles generated at the time of pasting can be efficiently removed, and the heat radiating sheet 5D and the heat spreader 103 can be brought into close contact with each other. Moreover, it can suppress that an air pocket is formed in the back surface side of the reflective sheet 104 of the thermal radiation sheet
  • the liquid crystal display device according to the present invention can be used for a television receiver, a PC monitor and the like.

Abstract

In order to prevent the occurrence of luminance variation in the emitted planar light and the deformation of a reflective sheet even when heat is generated from a light source and such, a backlight (1) is provided with a heat-releasing sheet (5) which has a plurality of slits (51) and is disposed on a section in the vicinity of a light source unit (3) on the bottom (100) of a backlight chassis (10).

Description

バックライト及び液晶表示装置Backlight and liquid crystal display device
　本発明は、光源にＬＥＤを用いたエッジライト方式のバックライト及び前記バックライトを用いた液晶表示装置に関するものである。 The present invention relates to an edge light type backlight using an LED as a light source and a liquid crystal display device using the backlight.
　液晶表示装置は、液晶パネルユニットと、前記液晶パネルユニットの背面に配置されるバックライトを備えており、前記液晶パネルユニットが、前記バックライトからの光の透過率（透過量）を調整し、前記液晶パネルユニットの前面に映像を表示している。 The liquid crystal display device includes a liquid crystal panel unit and a backlight disposed on the back surface of the liquid crystal panel unit, and the liquid crystal panel unit adjusts a light transmittance (amount of transmission) from the backlight, An image is displayed on the front surface of the liquid crystal panel unit.
　前記バックライトとして、導光板の側面から光を入射させる導光板方式（エッジライト方式）がある。エッジライト方式のバックライトは導光板の側面より光を入射する構造のため、輝度分布が均一で大きな面状光を出射するのが困難であった。そのため、エッジライト方式のバックライトは、ノートブック型ＰＣのモニタや遊技機のモニタのような小型の液晶表示装置に用いられることが多かった。 As the backlight, there is a light guide plate method (edge light method) in which light is incident from the side surface of the light guide plate. Since the edge light type backlight has a structure in which light is incident from the side surface of the light guide plate, it is difficult to emit large planar light with a uniform luminance distribution. Therefore, an edge light type backlight is often used for a small liquid crystal display device such as a notebook PC monitor or a gaming machine monitor.
　近年、導光板の精度の向上、光源として用いられるＬＥＤの高輝度化等によって、輝度分布が均一で大きな面状光を出射することが可能となった。また、前記液晶表示装置に対する薄型化及び小型化の要求の高まっていることもあり、大型テレビのような大型の液晶表示装置でも、前記エッジライト方式のバックライトを採用することが増えてきている。 In recent years, it has become possible to emit large planar light with a uniform luminance distribution by improving the accuracy of the light guide plate and increasing the luminance of the LED used as the light source. In addition, there is an increasing demand for thinning and miniaturization of the liquid crystal display device, and the use of the edge light type backlight is increasing even in a large liquid crystal display device such as a large television. .
　以下に、エッジライト方式のバックライトについて説明する。エッジライト方式のバックライトは、光源であるＬＥＤが複数個並んで配置された光源ユニットと、光源ユニットから出射された光を側面の受光面から受光し、一方の主面の出光面より面状光を出射する導光板と、導光板の出光面に隣接して配置された光学シートと、導光板の出光面の反対側の面に隣接して配置された反射シートとを備えている。そして、これらの部材は、バックライトシャーシの内部に配置されている。 The following describes the edge light type backlight. The edge-light type backlight has a light source unit in which a plurality of LEDs as light sources are arranged side by side, and light emitted from the light source unit is received from the light receiving surface on the side surface, and is more planar than the light exit surface of one main surface A light guide plate that emits light, an optical sheet that is disposed adjacent to the light exit surface of the light guide plate, and a reflective sheet that is disposed adjacent to a surface opposite to the light exit surface of the light guide plate are provided. These members are arranged inside the backlight chassis.
　従来のバックライトにおいて、前記反射シートは四隅をねじ、ピン等で位置決め、固定するようになっている。このような反射シートでは光源ユニットが発する熱によって変形（膨張）すると、四隅が固定されていることから変形量を吸収することができず、しわやたわみが発生する場合がある。このような熱による変形を抑制するため、バックライトシャーシの光源ユニットと近接した部分に、ヒートスプレッダが取り付けられている。前記ヒートスプレッダによって、前記光源ユニットから発せられる熱を外部に放熱している。 In the conventional backlight, the reflection sheet is positioned and fixed at the four corners with screws, pins or the like. In such a reflection sheet, when the light source unit is deformed (expanded) by heat generated, the four corners are fixed, so that the amount of deformation cannot be absorbed, and wrinkles and deflection may occur. In order to suppress such heat deformation, a heat spreader is attached to a portion of the backlight chassis adjacent to the light source unit. The heat spreader radiates heat generated from the light source unit to the outside.
　しかしながら、前記ヒートスプレッダだけでは、前記光源ユニットからの熱を十分に放出できない場合が多く、バックライトシャーシの内部に配置される前記反射シートに熱が伝達されてしまう。前記反射シートは、その熱で変形（膨張）し、しわ、たわみ等の起伏が発生する。この起伏によって、反射シートで反射される光の方向が乱れ、面状光の輝度むらの原因となる場合がある。 However, in many cases, the heat spreader alone cannot sufficiently release heat from the light source unit, and heat is transmitted to the reflection sheet disposed inside the backlight chassis. The reflection sheet is deformed (expanded) by the heat, and undulations such as wrinkles and deflection occur. Due to this undulation, the direction of the light reflected by the reflection sheet is disturbed, which may cause uneven brightness of the planar light.
　前記反射シートの熱による変形を抑制するため、例えば、特開２００４－１０１６９３号公報に記載の面状光源装置（バックライト）では、グラファイト等の熱伝導性の高い材料で形成された伝熱シートを反射シートの背面に配置するものが提案されている。前記伝熱シートが、反射シートの熱を外部に放出するのを補助するので、前記反射シートが熱によって変形するのを抑制することが可能である。 In order to suppress deformation of the reflection sheet due to heat, for example, in a planar light source device (backlight) described in Japanese Patent Application Laid-Open No. 2004-101893, a heat transfer sheet formed of a material having high thermal conductivity such as graphite. Has been proposed which is arranged on the back side of the reflection sheet. Since the heat transfer sheet assists in releasing the heat of the reflection sheet to the outside, it is possible to suppress the reflection sheet from being deformed by heat.
　前記放熱シートは前記反射シートの背面に配置されるものであるので、前記反射シートに凹凸が形成されるのを防ぐため、薄く形成されている。また、前記放熱シートは粘着シート状に形成されており、前記バックライトシャーシに容易に貼り付けることができるようになっている。 Since the heat dissipation sheet is disposed on the back surface of the reflection sheet, the heat dissipation sheet is formed thin in order to prevent unevenness from being formed on the reflection sheet. Moreover, the said heat radiating sheet is formed in the adhesive sheet shape, and can be easily affixed on the said backlight chassis.
特開２００４－１０１６９３号公報JP 2004-101893 A
　しかしながら、前記放熱シートはその材質、薄さ等によって、破れやすい性質を有しており、張力をかけた状態での作業が難しく、しわが発生しないように貼り付けるのが難しく、高度な技術を要する。また、しわが発生することで、前記放熱シートと前記ヒートスプレッダとの間に空気の層（いわゆる、空気溜まり）が形成されてしまう場合が多い。空気は放熱シートに比べて熱伝導率が低いので、前記空気溜まりによって、前記ＬＥＤ基板から前記ヒートスプレッダ、あるいは、前記反射シートから前記ヒートスプレッダへの熱伝導が低下する。 However, the heat-dissipating sheet has the property of being easily torn due to its material, thinness, etc., it is difficult to work in a state where tension is applied, and it is difficult to stick it so that wrinkles do not occur, and advanced technology is required. Cost. In addition, wrinkles often form an air layer (so-called air pocket) between the heat dissipation sheet and the heat spreader. Since air has a lower thermal conductivity than the heat dissipation sheet, heat conduction from the LED substrate to the heat spreader or from the reflective sheet to the heat spreader decreases due to the air accumulation.
　また、また、前記放熱シートは、一度貼ってしまうと、はがして張りなおす（リワークする）のが困難であり、また、気密性が高い素材であることから、一度空気溜まりが形成されてしまうと、空気溜まりを取り除くのが困難である。また、前記放熱シートの前記反射シートの背面に配置される部分で空気溜まりが形成されてしまうと、前記反射シートが前記放熱シートの空気溜まりに押されて起伏が形成され、反射の方向が乱れ、輝度むらの原因になる場合もある。 In addition, once the heat-dissipating sheet is pasted, it is difficult to peel off and re-stretch (rework), and since it is a highly airtight material, once an air pocket is formed. It is difficult to remove air pockets. In addition, if an air pocket is formed in a portion of the heat radiating sheet disposed on the back surface of the reflective sheet, the reflective sheet is pushed by the air pocket of the heat radiating sheet to form undulations, and the direction of reflection is disturbed. In some cases, it may cause uneven brightness.
　そこで本発明は、光源等からの熱による反射シートの変形を抑制し、出射される面状光の輝度むらの発生を抑制することができるバックライトを提供することを目的とする。 Therefore, an object of the present invention is to provide a backlight capable of suppressing the deformation of the reflection sheet due to heat from a light source or the like and suppressing the occurrence of luminance unevenness of the emitted planar light.
　上記目的を達成するため本発明は、導光板の側面に配置され、複数個の光源を並べて配置した光源ユニットと、少なくとも可視光領域の光を反射する反射シートと、前記光源ユニット、前記導光板及び前記反射シートが配置されるバックライトシャーシと、前記バックライトシャーシの前記光源ユニットが配置される部分に取付けられ、前記光源ユニットからの熱を放熱するヒートスプレッダと、前記ヒートスプレッダの上部及び前記バックライトシャーシの底部の前記光源ユニットに近接した部分の上部に配置され、複数個のスリットを有する放熱シートと、を備えていることを特徴とするバックライト。 In order to achieve the above object, the present invention provides a light source unit that is arranged on a side surface of a light guide plate and that has a plurality of light sources arranged side by side, a reflective sheet that reflects at least light in the visible light region, the light source unit, and the light guide plate. And a backlight chassis in which the reflection sheet is disposed, a heat spreader that is attached to a portion of the backlight chassis in which the light source unit is disposed, and dissipates heat from the light source unit, an upper portion of the heat spreader, and the backlight A backlight comprising: a heat dissipating sheet disposed on an upper portion of a bottom portion of the chassis adjacent to the light source unit and having a plurality of slits.
　この構成によると、放熱シートをヒートスプレッダ及びバックライトシャーシの底部に配置するとき、しわが形成され、そのしわの部分に空気層が形成されてしまった場合でも、空気層の空気をスリットより外部に排出することが可能である。 According to this configuration, when the heat-dissipating sheet is disposed at the bottom of the heat spreader and the backlight chassis, even if wrinkles are formed and an air layer is formed in the wrinkled part, the air in the air layer is moved outside from the slits. It is possible to discharge.
　このことから、前記放熱シートと前記ヒートスプレッダ又は前記バックライトシャーシの底部との間に空気層が残る（空気溜りが形成される）のを抑制することができる。熱伝導の悪い空気溜りのせいで、熱伝導が低下するのを抑制することができ、ＬＥＤが高温になって発光効率が低下するのを抑制することができる。 From this, it is possible to suppress an air layer from being left (an air pocket is formed) between the heat dissipation sheet and the heat spreader or the bottom of the backlight chassis. It is possible to suppress a decrease in heat conduction due to an air reservoir having poor heat conduction, and it is possible to suppress a decrease in luminous efficiency due to high temperature of the LED.
　また、放熱シートとヒートスプレッダ及び（又は）底部との間に空気溜まりが形成されていることで、反射シートが盛り上がり、反射光の方向が乱れるのを抑制することができる。 Further, since the air reservoir is formed between the heat radiation sheet and the heat spreader and / or the bottom, it is possible to suppress the reflection sheet from rising and disturbing the direction of the reflected light.
　上記構成において、前記複数個のスリットが、前記光源ユニットに沿って並んで配置されていてもよい。 In the above configuration, the plurality of slits may be arranged side by side along the light source unit.
　上記構成において、前記複数個のスリットが、前記放熱シートの辺縁部より内側にむかって形成された切込みであってもよい。 In the above configuration, the plurality of slits may be cuts formed inwardly from the edge of the heat dissipation sheet.
　上記構成において、前記複数個のスリットそれぞれの先端部分は、鈍角又は曲線で形成された形状の貫通孔が連結されていてもよい。 In the above-described configuration, the tip of each of the plurality of slits may be connected to a through hole having a shape formed by an obtuse angle or a curve.
　上記構成において、前記放熱シートには、対向する辺のそれぞれに複数個のスリットが形成されており、対向する辺のスリットの先端は、対向する辺に形成されたスリットの先端と隣り合うように形成されていてもよい。 In the above configuration, the heat dissipation sheet has a plurality of slits formed on each of the opposing sides, and the leading ends of the slits on the opposing sides are adjacent to the leading ends of the slits formed on the opposing sides. It may be formed.
　上記構成において、前記放熱シートは、前記複数個のスリットの先端のさらに先の部分に複数個の貫通孔が形成されていてもよい。 In the above-described configuration, the heat radiating sheet may have a plurality of through holes formed at a further portion of the ends of the plurality of slits.
　上述したバックライトを利用した機器として、前記バックライトの全面側に配置された液晶パネルユニットを備えた液晶表示装置を挙げることができる。 Examples of the apparatus using the above-described backlight include a liquid crystal display device including a liquid crystal panel unit disposed on the entire surface side of the backlight.
　本発明によると、放熱シートを貼り付けるときに、空気溜まりが形成されるのを抑制することができ、光源であるＬＥＤの発熱を放熱シートで効率よく放熱することが可能となっている。 According to the present invention, it is possible to suppress the formation of air pockets when the heat dissipation sheet is attached, and it is possible to efficiently dissipate heat generated by the LED, which is a light source, with the heat dissipation sheet.
　このことから、光源からの熱が反射シートに伝わりにくく、しわになりにくく、光を正確な方向に反射することが可能である。これにより、導光板より出射される面状光の均一度を高くすることが可能である。また、面状光の均一度が高くなることから、液晶表示装置で表示される映像を高品質で維持することが可能である。 Therefore, it is difficult for heat from the light source to be transmitted to the reflection sheet and to be wrinkled, and it is possible to reflect light in an accurate direction. Thereby, the uniformity of the planar light emitted from the light guide plate can be increased. Further, since the uniformity of the planar light becomes high, it is possible to maintain the video displayed on the liquid crystal display device with high quality.
本発明にかかるバックライトを備えた液晶表示装置の一例の分解斜視図である。It is a disassembled perspective view of an example of the liquid crystal display device provided with the backlight concerning this invention. 図１に示す液晶表示装置の断面図である。It is sectional drawing of the liquid crystal display device shown in FIG. 放熱シートが取り付けられたバックライトを示す図である。It is a figure which shows the backlight with which the thermal radiation sheet was attached. 放熱シートの拡大図である。It is an enlarged view of a thermal radiation sheet. 本発明にかかるバックライトの他の例に用いられる放熱シートの拡大図である。It is an enlarged view of the thermal radiation sheet | seat used for the other example of the backlight concerning this invention. 本発明にかかるバックライトのさらに他の例に用いられる放熱シートの拡大図である。It is an enlarged view of the thermal radiation sheet | seat used for the further another example of the backlight concerning this invention. 本発明にかかるバックライトの他の例に用いられる放熱シートの拡大図である。It is an enlarged view of the thermal radiation sheet | seat used for the other example of the backlight concerning this invention.
　以下に本発明の実施形態について図面を参照して説明する。 Embodiments of the present invention will be described below with reference to the drawings.
　図１は本発明にかかるバックライトを備えた液晶表示装置の一例の分解斜視図であり、図２は図１に示す液晶表示装置の断面図である。図１、図２に示すように、液晶表示装置Ａは、バックライト１及び液晶パネルユニット６を備えている。液晶表示装置Ａは、バックライト１の前面側（観察者側）に液晶パネルユニット６が配置され、液晶パネルユニット６は前面側を中央部に開口窓７０を備えた金属製のベゼル７に押えられている。なお、図１、図２に示す液晶表示装置Ａでは、紙面上側が前面、すなわち、観察者側であり、下側が背面として説明する。また、以下において、特に記載されていない場合、図１あるいは図２の状態における前面及び背面を基準に説明する。 FIG. 1 is an exploded perspective view of an example of a liquid crystal display device having a backlight according to the present invention, and FIG. 2 is a cross-sectional view of the liquid crystal display device shown in FIG. As shown in FIGS. 1 and 2, the liquid crystal display device A includes a backlight 1 and a liquid crystal panel unit 6. In the liquid crystal display device A, the liquid crystal panel unit 6 is disposed on the front side (observer side) of the backlight 1, and the liquid crystal panel unit 6 is held by a metal bezel 7 having an opening window 70 in the center. It has been. In the liquid crystal display device A shown in FIGS. 1 and 2, the upper side of the drawing is the front side, that is, the observer side, and the lower side is the back side. Further, in the following description, the description will be given with reference to the front surface and the back surface in the state of FIG. 1 or 2 unless otherwise specified.
　バックライト１は、面状光を液晶パネルユニット６に照射する照明装置である。バックライト１は、平板形状の導光板２と、導光板２の側面に形成された受光面２２に向けて光を照射する光源ユニット３と、導光板２と近接して配置された光学シート４とを備えている。また、バックライト１はバックライトシャーシ１０を備えており、少なくとも、導光板２及び光源ユニット３及び光学シート４がバックライトシャーシ１０の内部に配置される。なお、本発明の要部であるバックライト１の詳細については、後述する。 The backlight 1 is an illumination device that irradiates the liquid crystal panel unit 6 with planar light. The backlight 1 includes a flat light guide plate 2, a light source unit 3 that emits light toward a light receiving surface 22 formed on a side surface of the light guide plate 2, and an optical sheet 4 that is disposed in the vicinity of the light guide plate 2. And. The backlight 1 includes a backlight chassis 10, and at least the light guide plate 2, the light source unit 3, and the optical sheet 4 are disposed inside the backlight chassis 10. In addition, the detail of the backlight 1 which is the principal part of this invention is mentioned later.
　液晶パネルユニット６は、液晶が封入された液晶パネル６１と、液晶パネル６１の前面（観察者側）及び背面（バックライト１側）に貼り付けられた偏光板６２とを有している。また、図２に示すように、液晶パネル６１は、アレイ基板６１１と、アレイ基板６１１と対向して配置された対向基板６１２と、アレイ基板と対向基板との間に充填される液晶とを含んでいる。 The liquid crystal panel unit 6 includes a liquid crystal panel 61 in which liquid crystal is sealed, and a polarizing plate 62 attached to the front surface (observer side) and the back surface (backlight 1 side) of the liquid crystal panel 61. As shown in FIG. 2, the liquid crystal panel 61 includes an array substrate 611, a counter substrate 612 arranged to face the array substrate 611, and liquid crystal filled between the array substrate and the counter substrate. It is out.
　アレイ基板６１１には、互いに直交するソース配線及びゲート配線、ソース配線及びゲート配線に接続されたスイッチング素子（例えば、薄膜トランジスタ）、スイッチング素子に接続された画素電極及び配向膜等が設けられている。そして、対向基板６１２には、赤、緑、青（ＲＧＢ）の各着色部が所定の配列で配置されたカラーフィルタ、共通電極、配向膜等が設けられている。 The array substrate 611 is provided with a source wiring and a gate wiring orthogonal to each other, a switching element (for example, a thin film transistor) connected to the source wiring and the gate wiring, a pixel electrode connected to the switching element, an alignment film, and the like. The counter substrate 612 is provided with a color filter in which colored portions of red, green, and blue (RGB) are arranged in a predetermined arrangement, a common electrode, an alignment film, and the like.
　図２に示すように、アレイ基板６１１は、対向基板６１２よりも突出して形成されている。この突出部分にスイッチング素子を駆動するための回路が形成されており、フレキシブル基板８１を介して駆動基板８が接続されている。駆動基板８はフレキシブル基板８１を介し、アレイ基板６１１のスイッチング素子に駆動信号を送信している。スイッチング素子が駆動されることで、液晶パネル６１の各画素におけるアレイ基板６１１の画素電極と対向基板６１２の対向電極ｋとの間に電圧が印加される。アレイ基板６１１と対向基板６１２の間の電圧が変化することで、各画素での光の透過度合が変更される。これにより、液晶パネル６１の観察者側の画像表示領域に画像を表示する。 As shown in FIG. 2, the array substrate 611 is formed so as to protrude from the counter substrate 612. A circuit for driving the switching element is formed in the protruding portion, and the drive substrate 8 is connected via the flexible substrate 81. The drive substrate 8 transmits a drive signal to the switching elements of the array substrate 611 via the flexible substrate 81. By driving the switching element, a voltage is applied between the pixel electrode of the array substrate 611 and the counter electrode k of the counter substrate 612 in each pixel of the liquid crystal panel 61. By changing the voltage between the array substrate 611 and the counter substrate 612, the light transmission degree in each pixel is changed. As a result, an image is displayed in the image display area on the viewer side of the liquid crystal panel 61.
　ベゼル７は、金属製の枠体であり、液晶パネルユニット６の前面の辺縁部分を覆う形状を有している。図２に示すように、ベゼル７は、液晶パネルユニット６の映像表示領域が隠れないように形成された矩形の開口窓７０と、液晶パネルユニット６を前面側から押える押え部７１と、押え部７１の辺縁部より背面側に突出し、液晶パネルユニット６及びバックライト１の辺縁部を覆うカバー部７２とを備えている。ベゼル７は接地されており、液晶パネルユニット６及びバックライト１をシールドしている。 The bezel 7 is a metal frame, and has a shape that covers the front edge of the liquid crystal panel unit 6. As shown in FIG. 2, the bezel 7 includes a rectangular opening window 70 formed so that the image display area of the liquid crystal panel unit 6 is not hidden, a presser 71 that presses the liquid crystal panel unit 6 from the front side, and a presser A cover portion 72 that protrudes from the edge portion of 71 to the back side and covers the edge portion of the liquid crystal panel unit 6 and the backlight 1 is provided. The bezel 7 is grounded and shields the liquid crystal panel unit 6 and the backlight 1.
　駆動基板８は、バックライト１に備えられた後述のシャーシケース１０２に取り付けられている。 The drive substrate 8 is attached to a chassis case 102 described later provided in the backlight 1.
（第１の実施形態）
　本発明にかかるバックライトの詳細について、新たな図面を参照して説明する。図２に示すように、バックライト１は、上述した、導光板２、光源ユニット３、光学シート４に加え、反射シート１０４が、バックライトシャーシ１０の内部に配置されている。また、光学シート４の前面側（液晶パネルユニット側）は、辺縁部をシャーシケース１０２に押えられている。 (First embodiment)
The details of the backlight according to the present invention will be described with reference to a new drawing. As shown in FIG. 2, in the backlight 1, in addition to the light guide plate 2, the light source unit 3, and the optical sheet 4 described above, a reflective sheet 104 is disposed inside the backlight chassis 10. Further, the edge side of the front side of the optical sheet 4 (liquid crystal panel unit side) is held by the chassis case 102.
　図１、図２に示すように、バックライトシャーシ１０は、前面側（液晶パネルユニット側）が開口した箱状の部材であり、平面視長方形状の底部１００と、底部１００より突出した側壁部１０１とを備えている。また、バックライトシャーシ１０は、底部１００を有する枠部材ということもできる。 As shown in FIGS. 1 and 2, the backlight chassis 10 is a box-shaped member whose front side (liquid crystal panel unit side) is open, and has a bottom 100 that is rectangular in plan view, and a side wall that protrudes from the bottom 100. 101. The backlight chassis 10 can also be referred to as a frame member having a bottom 100.
　バックライトシャーシ１０の底部１００の長辺には、光源ユニット３が固定され、光源ユニット３からの熱を放熱するためのヒートスプレッダ１０３が取り付けられている。ヒートスプレッダ１０３には、側壁部１０１と一体化される壁体が形成されており、壁体に光源ユニット３が固定されている。 The light source unit 3 is fixed to the long side of the bottom 100 of the backlight chassis 10, and a heat spreader 103 for radiating heat from the light source unit 3 is attached. The heat spreader 103 is formed with a wall body integrated with the side wall portion 101, and the light source unit 3 is fixed to the wall body.
　ヒートスプレッダ１０３は光源ユニット３より出射された熱が伝達され、その熱を外部に放出するための部材であり、バックライトシャーシ１０よりも熱伝導率の高い材料（例えば、アルミニウム、ステンレス等の金属）で形成されている。ヒートスプレッダ１０３と反射シート１０４との間には、光源ユニット３から反射シート１０４に伝達された熱を効率よくヒートスプレッダ１０３に伝導させるための放熱シート５が配置されている。 The heat spreader 103 is a member for transferring the heat emitted from the light source unit 3 and releasing the heat to the outside, and a material having a higher thermal conductivity than the backlight chassis 10 (for example, a metal such as aluminum or stainless steel). It is formed with. Between the heat spreader 103 and the reflection sheet 104, a heat dissipation sheet 5 for efficiently transferring the heat transmitted from the light source unit 3 to the reflection sheet 104 to the heat spreader 103 is disposed.
　導光板２は、ポリメチルメタクリレート（ＰＭＭＡ）、ポリカーボネイト等の透明な樹脂を平板形状に成形したものである。なお、これらの樹脂に限定されるものではなく、透明な平板形状に形成することができるものを広く採用することができる。 The light guide plate 2 is formed by forming a transparent resin such as polymethyl methacrylate (PMMA) or polycarbonate into a flat plate shape. In addition, it is not limited to these resin, The thing which can be formed in a transparent flat plate shape can be employ | adopted widely.
　図１に示すように、導光板２は平面視長方形状の平板部材である。液晶パネルユニット６と対向する主面が出光面２１として、短手方向の側面が光源ユニット３からの光を受光する受光面２２として構成されている。 As shown in FIG. 1, the light guide plate 2 is a flat plate member having a rectangular shape in plan view. The main surface facing the liquid crystal panel unit 6 is configured as a light output surface 21, and the side surface in the short direction is configured as a light receiving surface 22 that receives light from the light source unit 3.
　光源ユニット３は、受光面２２と対向して配置される長尺形状のＬＥＤアレイ基板３０と、ＬＥＤアレイ基板３０上に直線状に配列された複数個（８個）のＬＥＤ３１（光源）を備えている。なお、光源ユニット３では、ＬＥＤ３１は等間隔で配列されているが、部分的に間隔を変えた配列であってもよい。図２に示すように、ＬＥＤアレイ基板３０がバックライトシャーシ１０の側壁部１０１に取り付け固定されている。このとき、ＬＥＤ３１がバックライト１の内側、すなわち、導光板２の受光面２２に対向する。これにより、ＬＥＤ３１から出射された光が、受光面２２に入射する。 The light source unit 3 includes a long LED array substrate 30 disposed to face the light receiving surface 22, and a plurality (eight) of LEDs 31 (light sources) arranged linearly on the LED array substrate 30. ing. In the light source unit 3, the LEDs 31 are arranged at equal intervals, but may be an arrangement in which the intervals are partially changed. As shown in FIG. 2, the LED array substrate 30 is attached and fixed to the side wall portion 101 of the backlight chassis 10. At this time, the LED 31 faces the inside of the backlight 1, that is, the light receiving surface 22 of the light guide plate 2. Thereby, the light emitted from the LED 31 enters the light receiving surface 22.
　光学シート４は、光学シート部材として、導光板２の出光面２１より出射される光を拡散する拡散シート４１と、輝度を向上する輝度向上シート（ＤＢＥＦ）４２と、出光面２１より出射される光の方向を揃える、すなわち、斜めに進入した光を液晶パネルユニット６に向くように方向を変えるプリズムシート４３とを備えている。なお、これら以外の光学特性を有する光学シート部材を用いる場合もある。 The optical sheet 4 is emitted from the light exit surface 21 as an optical sheet member, a diffusion sheet 41 that diffuses the light emitted from the light exit surface 21 of the light guide plate 2, a brightness enhancement sheet (DBEF) 42 that improves brightness. A prism sheet 43 is provided that aligns the direction of light, that is, changes the direction so that light entering obliquely faces the liquid crystal panel unit 6. An optical sheet member having optical characteristics other than these may be used.
　次に本発明にかかるバックライトに用いられる放熱シートの詳細について新たな図面を参照して説明する。図３Ａは放熱シートが取り付けられたバックライトを示す図であり、図３Ｂは放熱シートの拡大図である。なお、図３Ａに示しているように、バックライトシャーシ１０の長手方向をＸ方向、短手方向をＹ方向としており、以下の説明でも、同様にＸ方向、Ｙ方向を用いて説明する場合がある。また、図３Ａ、図３Ｂに示すバックライトでは、導光板２、光学シート４の表示を省略している。 Next, details of the heat dissipation sheet used in the backlight according to the present invention will be described with reference to a new drawing. FIG. 3A is a view showing a backlight to which a heat dissipation sheet is attached, and FIG. 3B is an enlarged view of the heat dissipation sheet. As shown in FIG. 3A, the longitudinal direction of the backlight chassis 10 is the X direction, and the short direction is the Y direction. In the following description, the X direction and the Y direction may be used similarly. is there. 3A and 3B, the light guide plate 2 and the optical sheet 4 are not shown.
　図３Ａ、図３Ｂに示すように、放熱シート５は、ヒートスプレッダ１０３と一部重なるように取り付けられている。詳しく説明すると、放熱シート５は、光源ユニット３のＬＥＤ３１が配置されている部分に取り付けられており、ＬＥＤ３１から発せられる熱を効率よくヒートスプレッダ１０３に伝達する。 3A and 3B, the heat dissipation sheet 5 is attached so as to partially overlap the heat spreader 103. More specifically, the heat radiating sheet 5 is attached to a portion of the light source unit 3 where the LED 31 is disposed, and efficiently transmits heat generated from the LED 31 to the heat spreader 103.
　放熱シート５は、グラファイト等の熱伝導率の高い材料を含む薄膜シートであり、一方の面が粘着面に形成された粘着シートである。グラファイトを含む放熱シート５は、その性質上、破損しやすく、貼り直し（リワーク）が難しい。さらに、薄膜シートであることから、バックライトシャーシ１０に貼り付けるときに、放熱シート５にしわが形成されやすい。また、しわに溜まる、いわゆる、空気溜まりが形成やすい。空気だまりが形成されると、光源ユニット３からヒートスプレッダ１０３或いは反射シート１０４からヒートスプレッダ１０３への熱の伝導が悪くなる。 The heat radiating sheet 5 is a thin film sheet containing a material having high thermal conductivity such as graphite, and one surface is an adhesive sheet formed on an adhesive surface. The heat-dissipating sheet 5 containing graphite is easily damaged due to its nature, and it is difficult to rework (rework). Furthermore, since it is a thin film sheet, wrinkles are easily formed in the heat dissipation sheet 5 when it is attached to the backlight chassis 10. In addition, a so-called air pocket that is wrinkled is easily formed. When the air pool is formed, heat conduction from the light source unit 3 to the heat spreader 103 or from the reflection sheet 104 to the heat spreader 103 is deteriorated.
　そこで、図３Ｂに示すように放熱シート５に、スリット５１を形成することで、空気溜まりを抑制している。スリット５１による空気溜まりを抑制する方法について説明する。放熱シート５をしわができないように貼り付けるには特殊な道具や技術が必要であり困難である。そこで、放熱シート５はある程度のしわが形成されることを前提としてヒートスプレッダ１０３及びバックライトシャーシ１０に貼り付けられる。放熱シート５は粘着シートであり、しわに溜まった空気は、放熱シート５を押えることである程度移動させることが可能である。スリット５１を所定の間隔で形成しておくことで、しわに溜まった空気をスリット５１まで押し、スリット５１から抜くことが可能である。 Therefore, as shown in FIG. 3B, air pockets are suppressed by forming slits 51 in the heat dissipating sheet 5. A method for suppressing air accumulation by the slit 51 will be described. It is difficult to attach the heat dissipating sheet 5 so as not to be wrinkled, requiring special tools and techniques. Therefore, the heat radiating sheet 5 is attached to the heat spreader 103 and the backlight chassis 10 on the assumption that a certain amount of wrinkles are formed. The heat radiation sheet 5 is an adhesive sheet, and the air accumulated in the wrinkles can be moved to some extent by pressing the heat radiation sheet 5. By forming the slits 51 at a predetermined interval, the air accumulated in the wrinkles can be pushed to the slits 51 and can be extracted from the slits 51.
　以上の方法で、放熱シート５とヒートスプレッダ１０３との間に空気溜まりが形成されるのを抑制できる、換言すると、放熱シート５とヒートスプレッダ１０３とを密着させることができる。このことから、空気溜まりによって光源ユニット３からヒートスプレッダ１０３への熱伝導が低下するのを抑制できる。このことより、光源ユニット３の熱の多くは放熱シート５を介してヒートスプレッダに伝達され、光源ユニット３から反射シート１０４に伝導される熱量を減らすことが可能である。さらに、反射シート１０４の光源ユニット３に近い部分が放熱シート５と接触しているので、光源ユニット３より反射シート１０４に伝達された熱も、放熱シート５を介してヒートスプレッダ１０３に効率よく逃がされる。 By the above method, it is possible to suppress the formation of an air pocket between the heat radiation sheet 5 and the heat spreader 103. In other words, the heat radiation sheet 5 and the heat spreader 103 can be brought into close contact with each other. From this, it can suppress that the heat conduction from the light source unit 3 to the heat spreader 103 falls by the air pocket. Thus, most of the heat of the light source unit 3 is transmitted to the heat spreader via the heat radiating sheet 5, and the amount of heat conducted from the light source unit 3 to the reflection sheet 104 can be reduced. Further, since the portion of the reflective sheet 104 close to the light source unit 3 is in contact with the heat radiating sheet 5, the heat transmitted from the light source unit 3 to the reflective sheet 104 is also efficiently released to the heat spreader 103 via the heat radiating sheet 5. .
　以上のことより、反射シート１０４が高温になるのを抑制することができるので、反射シートがしわになったりたわんだりするのを抑制することができる。これにより、反射シートで反射される光の方向が乱れるのを抑制でき、バックライト１から出射される面状光の輝度ムラを抑制することができる。 From the above, since it is possible to suppress the reflection sheet 104 from becoming high temperature, it is possible to suppress the reflection sheet from being wrinkled or bent. Thereby, it can suppress that the direction of the light reflected by a reflecting sheet is disturbed, and the brightness nonuniformity of the planar light radiate | emitted from the backlight 1 can be suppressed.
　なお、図３Ｂ等に示すように、放熱シート５では、スリット５１が放熱シート５の辺縁部より内側に延びる切り込み状態のものとしているが、これに限定されるものではなく、例えば、放熱シート５の内部に形成され両端部が辺縁部に到達しないものであってもよい。放熱シート５を貼り付けるときに発生するしわに入る空気を効果的に抜くことができる切欠きを広く採用することが可能である。また、スリット５１として、切り込み形状ではなく、矩形状あるいは三角形状の切り欠き形状であってもよい。以下の実施形態でも同様である。 As shown in FIG. 3B and the like, in the heat radiating sheet 5, the slit 51 is in a cut state extending inward from the edge of the heat radiating sheet 5, but is not limited thereto. 5 may be formed in both ends so as not to reach the edge. It is possible to widely employ a notch that can effectively remove the air entering the wrinkle generated when the heat radiation sheet 5 is attached. Further, the slit 51 may have a rectangular or triangular cutout shape instead of the cut shape. The same applies to the following embodiments.
（第２の実施形態）
　本発明にかかるバックライトの詳細について、新たな図面を参照して説明する。図４は本発明にかかるバックライトの他の例に用いられる放熱シートの拡大図である。図４に示すように、放熱シート５Ｂには、円形状の貫通孔５２ｂが形成されており、スリット５１ｂの先端が貫通孔５２ｂと接続している。このように、スリット５１ｂの先端に貫通孔５２ｂが形成されていることで、スリット５１ｂの先端に応力が集中するのを抑制することができる。これにより、放熱シート５Ｂをバックライトシャーシ１０３に貼り付けるとき、スリット５１ｂの先端から放熱シート５Ｂが裂けるのを抑制することができる。 (Second Embodiment)
The details of the backlight according to the present invention will be described with reference to a new drawing. FIG. 4 is an enlarged view of a heat dissipation sheet used in another example of the backlight according to the present invention. As shown in FIG. 4, the heat radiating sheet 5B has a circular through hole 52b, and the tip of the slit 51b is connected to the through hole 52b. Thus, by forming the through hole 52b at the tip of the slit 51b, it is possible to prevent stress from concentrating on the tip of the slit 51b. Thereby, when sticking the heat-radiation sheet 5B to the backlight chassis 103, it can suppress that the heat-radiation sheet 5B tears from the front-end | tip of the slit 51b.
　なお、放熱シート５Ｂでは円形状の貫通孔５２ｂを備えているが、これに限定されるものではなく、放熱シート５Ｂをバックライトシャーシ１０に貼り付けるとき、応力が集中しやすい角部（例えば、鋭角、切込みの先端等）を備えない形状（たとえば、楕円、六角形等）の貫通孔としてもよい。 The heat dissipation sheet 5B includes the circular through-holes 52b. However, the present invention is not limited to this, and when the heat dissipation sheet 5B is attached to the backlight chassis 10, corner portions where stress is likely to concentrate (for example, It is good also as a through-hole of a shape (for example, an ellipse, a hexagon, etc.) which does not have an acute angle, the front-end | tip of cutting, etc.
　その他の効果については第１の実施形態と同じである。 Other effects are the same as those in the first embodiment.
（第３の実施形態）
　本発明にかかるバックライトの詳細について、新たな図面を参照して説明する。図５は本発明にかかるバックライトのさらに他の例に用いられる放熱シートの拡大図である。図５に示すように放熱シート５Ｃは、一定の幅（例えば、５ｃｍ等）があるので、スリット５１ｃが形成されている部分以外の部分にも空気溜まりが形成されやすい。そこで、スリット５１ｃが形成されている部分以外の部分に形成された空気を効果的に抜くため、放熱シート５Ｃには、円形の空気抜き孔５３ｃが複数個形成されている。 (Third embodiment)
The details of the backlight according to the present invention will be described with reference to a new drawing. FIG. 5 is an enlarged view of a heat dissipation sheet used in yet another example of the backlight according to the present invention. As shown in FIG. 5, since the heat radiation sheet 5C has a certain width (for example, 5 cm, etc.), an air pocket is easily formed in a portion other than the portion where the slit 51c is formed. Therefore, in order to effectively remove air formed in a portion other than the portion where the slit 51c is formed, a plurality of circular air vent holes 53c are formed in the heat dissipation sheet 5C.
　図５に示すように空気抜き孔５３ｃは一定の間隔を開けて整列して形成されている。このように空気抜き孔５３ｃが形成されていることで、放熱シート５Ｃとヒートスプレッダ１０３との密着を高めることができるので、光源ユニット３からヒートスプレッダ１０３への熱の伝導、反射シート１０４からヒートスプレッダ１０３への熱の伝導を高めることが可能である。なお、本実施形態の放熱シート５Ｃでは、空気抜き孔５３ｃが円形の貫通孔であるが、それに限定されるものではなく、楕円、多角形等であってもよい。また、放熱シート５Ｃでは、空気抜き孔５３ｃが等間隔に並んでいるが、これに限定されるものではない。 As shown in FIG. 5, the air vent holes 53c are formed in a line with a predetermined interval. Since the air vent hole 53c is formed in this way, the close contact between the heat radiation sheet 5C and the heat spreader 103 can be enhanced. It is possible to increase heat conduction. In the heat dissipation sheet 5C of the present embodiment, the air vent hole 53c is a circular through hole, but is not limited thereto, and may be an ellipse, a polygon, or the like. Further, in the heat dissipation sheet 5C, the air vent holes 53c are arranged at equal intervals, but the present invention is not limited to this.
　その他の効果については第１の実施形態と同じである。 Other effects are the same as those in the first embodiment.
（第４の実施形態）
　本発明にかかるバックライトの詳細について、新たな図面を参照して説明する。図６は本発明にかかるバックライトの他の例に用いられる放熱シートの拡大図である。図６に示すように、放熱シート５Ｄでは、スリット５１ｄが形成されている辺と反対側の辺にも、補助スリット５４ｄが形成されている。スリット５１ｄと補助スリット５４ｄとは、交互に形成されており、スリット５１ｄと補助スリット５４ｄとが繋がらないように形成されている。 (Fourth embodiment)
The details of the backlight according to the present invention will be described with reference to a new drawing. FIG. 6 is an enlarged view of a heat dissipation sheet used in another example of the backlight according to the present invention. As shown in FIG. 6, in the heat dissipation sheet 5D, auxiliary slits 54d are also formed on the side opposite to the side where the slits 51d are formed. The slits 51d and the auxiliary slits 54d are alternately formed so that the slits 51d and the auxiliary slits 54d are not connected.
　このように補助スリット５４ｄが形成されていることで、放熱シート５Ｄでは、貼り付け時に発生するしわに溜まる空気を効率よく抜くことができ、放熱シート５Ｄとヒートスプレッダ１０３とを密着させることができる。また、放熱シート５Ｄの反射シート１０４の背面側に空気溜まりができるのを抑制することができ、反射シート１０４に起伏が形成されるのを抑制できる。 Since the auxiliary slit 54d is formed in this way, in the heat radiating sheet 5D, air accumulated in wrinkles generated at the time of pasting can be efficiently removed, and the heat radiating sheet 5D and the heat spreader 103 can be brought into close contact with each other. Moreover, it can suppress that an air pocket is formed in the back surface side of the reflective sheet 104 of the thermal radiation sheet | seat 5D, and can suppress that undulation is formed in the reflective sheet 104. FIG.
　その他の効果については第１の実施形態と同じである。 Other effects are the same as those in the first embodiment.
　以上、本発明の実施形態について説明したが、本発明はこの内容に限定されるものではない。また本発明の実施形態は、発明の趣旨を逸脱しない限り、種々の改変を加えることが可能である。 As mentioned above, although embodiment of this invention was described, this invention is not limited to this content. The embodiments of the present invention can be variously modified without departing from the spirit of the invention.
　本発明にかかる、液晶表示装置はテレビ受像機、ＰＣ用モニタ等に利用することが可能である。 The liquid crystal display device according to the present invention can be used for a television receiver, a PC monitor and the like.
１　バックライト
１０　バックライトフレーム
１００　底部
１０１　側壁部
１０２　シャーシケース
１０３　ヒートスプレッダ
１０４　反射シート
２　導光板
３　光源ユニット
３０　ＬＥＤアレイ基板
３１　ＬＥＤ
４　光学シート
４１　拡散シート
４２　輝度向上シート
４３　プリズムシート
５　放熱シート
５１　スリット
５２ｂ　貫通孔
５３ｃ　空気抜き孔
５４ｄ　補助スリット
６　液晶パネルユニット
６１　液晶パネル
６２　偏光板
７　ベゼル
８　駆動基板 DESCRIPTION OF SYMBOLS 1 Backlight 10 Backlight frame 100 Bottom part 101 Side wall part 102 Chassis case 103 Heat spreader 104 Reflective sheet 2 Light guide plate 3 Light source unit 30 LED array board 31 LED
4 Optical sheet 41 Diffusion sheet 42 Brightness improving sheet 43 Prism sheet 5 Heat radiation sheet 51 Slit 52b Through hole 53c Air vent hole 54d Auxiliary slit 6 Liquid crystal panel unit 61 Liquid crystal panel 62 Polarizing plate 7 Bezel 8 Driving substrate

Claims (7)

  1. 　導光板の側面に配置され、複数個の光源を並べて配置した光源ユニットと、
    　少なくとも可視光領域の光を反射する反射シートと、
    　前記光源ユニット、前記導光板及び前記反射シートが配置されるバックライトシャーシと、
    　前記バックライトシャーシの前記光源ユニットが配置される部分に取付けられ、前記光源ユニットからの熱を放熱するヒートスプレッダと、
    　前記ヒートスプレッダの上部及び前記バックライトシャーシの底部の前記光源ユニットに近接した部分の上部に配置され、複数個のスリットを有する放熱シートと、を備えていることを特徴とするバックライト。     A light source unit arranged on a side surface of the light guide plate and arranged with a plurality of light sources arranged;
    A reflective sheet that reflects at least light in the visible light region;
    A backlight chassis in which the light source unit, the light guide plate and the reflective sheet are disposed;
    A heat spreader that is attached to a portion of the backlight chassis where the light source unit is disposed and radiates heat from the light source unit;
    A backlight comprising: a heat dissipating sheet disposed on an upper portion of the heat spreader and a portion of the bottom portion of the backlight chassis adjacent to the light source unit and having a plurality of slits.
  2. 　前記複数個のスリットが、前記光源ユニットに沿って並んで配置されている請求項１に記載のバックライト。 The backlight according to claim 1, wherein the plurality of slits are arranged along the light source unit.
  3. 　前記複数個のスリットが、前記放熱シートの辺縁部より内側にむかって形成された切込みである請求項１又は請求項２に記載のバックライト。 The backlight according to claim 1 or 2, wherein the plurality of slits are cuts formed inwardly from the edge of the heat-dissipating sheet.
  4. 　前記複数個のスリットそれぞれの先端部分は、鈍角又は曲線で形成された形状の貫通孔が連結されている請求項３に記載のバックライト。 The backlight according to claim 3, wherein a tip portion of each of the plurality of slits is connected to a through hole having a shape formed by an obtuse angle or a curve.
  5. 　前記放熱シートは、前記複数個のスリットの先端のさらに先の部分に複数個の貫通孔が形成されている請求項１から請求項４のいずれかに記載のバックライト。 The backlight according to any one of claims 1 to 4, wherein the heat radiation sheet has a plurality of through holes formed at a further portion of the tips of the plurality of slits.
  6. 　前記放熱シートには、対向する辺のそれぞれに複数個のスリットが形成されており、
    　対向する辺のスリットの先端は、対向する辺に形成されたスリットの先端と隣り合うように形成されている請求項３又は請求項４に記載のバックライト。     In the heat dissipation sheet, a plurality of slits are formed on each of the opposing sides,
    5. The backlight according to claim 3, wherein the tip of the slit on the opposite side is formed adjacent to the tip of the slit formed on the opposite side.
  7. 　請求項１から請求項６のいずれかに記載のバックライトと、
    　前記バックライトの前面側に配置された液晶パネルユニットと、を備えた液晶表示装置。     The backlight according to any one of claims 1 to 6,
    And a liquid crystal panel unit disposed on the front side of the backlight.
PCT/JP2012/067312 2011-07-13 2012-07-06 Backlight, and liquid crystal display device WO2013008740A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2011155025 2011-07-13
JP2011-155025 2011-07-13

Publications (1)

Publication Number Publication Date
WO2013008740A1 true WO2013008740A1 (en) 2013-01-17

Family

ID=47506031

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2012/067312 WO2013008740A1 (en) 2011-07-13 2012-07-06 Backlight, and liquid crystal display device

Country Status (1)

Country Link
WO (1) WO2013008740A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014208368A1 (en) * 2013-06-27 2014-12-31 堺ディスプレイプロダクト株式会社 Light source device and display device

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004227941A (en) * 2003-01-23 2004-08-12 Seiko Epson Corp Backlight unit, electro-optical device, electronic apparatus, and manufacturing method of backlight unit and electro-optical device
JP2005038771A (en) * 2003-07-17 2005-02-10 Mitsubishi Electric Corp Surface light source, display device and guiding light device
JP2006154136A (en) * 2004-11-26 2006-06-15 Kyocera Corp Liquid crystal display device and display body using the same
JP2008299181A (en) * 2007-06-01 2008-12-11 Hitachi Ltd Liquid crystal display

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004227941A (en) * 2003-01-23 2004-08-12 Seiko Epson Corp Backlight unit, electro-optical device, electronic apparatus, and manufacturing method of backlight unit and electro-optical device
JP2005038771A (en) * 2003-07-17 2005-02-10 Mitsubishi Electric Corp Surface light source, display device and guiding light device
JP2006154136A (en) * 2004-11-26 2006-06-15 Kyocera Corp Liquid crystal display device and display body using the same
JP2008299181A (en) * 2007-06-01 2008-12-11 Hitachi Ltd Liquid crystal display

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014208368A1 (en) * 2013-06-27 2014-12-31 堺ディスプレイプロダクト株式会社 Light source device and display device
US10031278B2 (en) 2013-06-27 2018-07-24 Sakai Display Products Corporation Light source device and display device

Similar Documents

Publication Publication Date Title
KR101541352B1 (en) Liquid crystal display device
JP4840121B2 (en) Surface light source device
KR101001405B1 (en) Liquid crystal display device
US9746602B2 (en) Backlight device and display device including the same
US20140362325A1 (en) Display apparatus
WO2012023322A1 (en) Illumination device, display device and television receiver
US9507079B2 (en) Display apparatus
WO2011074354A1 (en) Illuminating device, display device, and television receiver
JP2007194022A (en) Surface light source device
US9016919B2 (en) Lighting device, display device and television receiver
WO2012081395A1 (en) Illumination device and liquid crystal display device comprising same
US20150226913A1 (en) Lighting device, display device and television device
KR20130046240A (en) Borderless liquid crystal display device
WO2012128193A1 (en) Lighting device and display device
WO2012169441A1 (en) Lighting device, display device and television receiver
WO2011089789A1 (en) Lighting device, display device, and television receiver
WO2013018648A1 (en) Illumination device, display device, and television receiving device
US20150293298A1 (en) Lighting device, display device, and television device
KR101818464B1 (en) Liquid Crystal Display
WO2013008741A1 (en) Backlight, and liquid crystal display device
WO2012077562A1 (en) Illumination device, display device and television receiving device
KR20120136879A (en) Liquid crystal display device
TWI470323B (en) Display device and back light module thereof
WO2013008740A1 (en) Backlight, and liquid crystal display device
WO2013077279A1 (en) Backlight unit and liquid crystal display device

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12811690

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12811690

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: JP