WO2013018499A1 - Backlight and liquid crystal display device - Google Patents

Backlight and liquid crystal display device Download PDF

Info

Publication number
WO2013018499A1
WO2013018499A1 PCT/JP2012/067216 JP2012067216W WO2013018499A1 WO 2013018499 A1 WO2013018499 A1 WO 2013018499A1 JP 2012067216 W JP2012067216 W JP 2012067216W WO 2013018499 A1 WO2013018499 A1 WO 2013018499A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
guide plate
led
light guide
backlight
Prior art date
Application number
PCT/JP2012/067216
Other languages
French (fr)
Japanese (ja)
Inventor
増田　純一
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 WO2013018499A1 publication Critical patent/WO2013018499A1/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
    • G02B6/0086—Positioning aspects
    • G02B6/0091—Positioning aspects of the light source relative to the light guide
    • 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
    • G02F1/133308—Support structures for LCD panels, e.g. frames or bezels
    • G02F1/133317—Intermediate frames, e.g. between backlight housing and front frame

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 are arranged side by side, receives light emitted from the light source unit from a light receiving surface on a side surface, and receives planar light from a light emitting surface of one main surface.
  • An output light guide plate, an optical sheet disposed adjacent to the light exit surface of the light guide plate, and a reflection sheet 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 light guide plate is used to efficiently cause the light emitted from the LED to enter the light guide plate, that is, to prevent the light emitted from the LED from coming off the light receiving surface. Is arranged so that the light receiving surface is close to the LED.
  • a semiconductor light emitting element such as an LED has a characteristic that the temperature rises when the input current increases. If the light receiving surface and the LED are too close together, it is difficult to release the heat of the LED, the temperature rises, and the light emission efficiency decreases. Due to the decrease in the light emission efficiency of the LED, uneven brightness of the planar light emitted from the backlight, a decrease in brightness, and the like have occurred, causing a decrease in the quality of the backlight.
  • FIG. 11 is a cross-sectional view of a conventional backlight with a countermeasure against heat.
  • the backlight 91 includes a light guide plate 92, a light source 95 including a film substrate 93 on which LEDs 931 are mounted in a row and a metal reflector 94, and a light source 95 attached to the light guide plate 92.
  • a frame-like frame 96 and a planar frame 97 for storing and holding are provided.
  • An optical sheet 98 made of a plurality of optical members is provided on the light exit surface of the light guide plate 92.
  • a metal thin film 932 and a soft aluminum sheet 933 are attached to the surface of the film substrate 93 where the LED 931 is not mounted.
  • the metal thin film 932 and the soft aluminum sheet 933 are held by the frame-shaped frame 96, and the frame-shaped frame 96 and the metal reflector 94 are attached by a heat-dissipating film sheet 90 (see Japanese Patent Application Laid-Open No. 2003-76287). .
  • the heat generated from the LED 931 is released to the frame-shaped frame 96 through the metal thin film 932 and the soft aluminum sheet 933 disposed in contact with the film substrate 93, so that the light guide plate 92 is heated by the heat generated from the LED 931 or the LED 931 itself. It is possible to suppress the temperature from rising. Thereby, the deterioration of the quality of the backlight by the heat
  • the heat generated from the LED 931 is transmitted to the film substrate 93 and is transmitted through the metal thin film 932 and the soft aluminum sheet 933 to the frame frame 96, the heat dissipation film sheet 90, and the planar shape.
  • heat is radiated to the frame 97, an air layer is easily formed between components (for example, the metal thin film 932 and the frame-shaped frame 96), which may cause a decrease in heat dissipation.
  • the light guide plate 92 is fixed by a plurality of members (planar frame 97, frame frame 96, etc.) and the light source 95 and the light guide plate 92 are disposed close to each other, the light guide plate 92 is likely to warp due to thermal expansion. When the light guide plate 92 is warped, the optical axes of the light receiving surface of the light guide plate 92 and the light emitting surface of the LED 931 are shifted, and light leakage is likely to occur. In addition, since the light source 95 and the light guide plate 92 are in contact with each other, when the light guide plate 92 expands due to the heat of the LED 931, the LED 931 may be pushed to destroy the LED 931.
  • the number of constituent members such as the metal thin film 932, the soft aluminum sheet 933, the heat dissipation film sheet 90, and the like increases, so that the time and labor required for the production increase, and the production cost tends to increase.
  • the present invention suppresses light leakage from the LED and reduction of the light emission efficiency of the LED without increasing the number of components, and provides an edge light type backlight having high light utilization efficiency and a liquid crystal display device using the backlight.
  • the purpose is to provide.
  • the present invention provides a light guide plate that receives light from a light receiving surface on a side surface and emits planar light from a light exit surface of one main surface, and an LED mounting in which a plurality of LEDs are mounted in a row. And an LED substrate having a U-shaped cross section including a first facing portion and a second facing portion that protrude from the LED mounting portion and surround the LED, and the LED substrate is mounted on the LED mounting surface.
  • a backlight attached to the light guide plate such that the portion faces the light receiving surface, the first facing portion contacts the light exit surface, and the second facing portion contacts the back surface of the light exit surface.
  • the LED substrate can efficiently dissipate heat, it is not necessary to provide a heat dissipating member, and accordingly, the increase in the number of members can be suppressed, which is advantageous for downsizing and weight reduction.
  • the LED substrate may be formed of a metal material.
  • the thermal conductivity of the LED substrate is high, an increase in temperature of the LED and the light guide plate can be suppressed. From this, the fall of the luminous efficiency of the said LED can be suppressed, and generation
  • the metal material constituting the LED substrate include aluminum and copper having high thermal conductivity. In addition to these, metals having high thermal conductivity can be employed.
  • the LED substrate may be manufactured by bending a flat metal substrate on which a notch is formed.
  • the LED substrate can be easily manufactured and processing accuracy can be increased, and a gap between the first facing portion and the light guide plate and between the second facing portion and the light guide plate is hardly generated. From this, it can suppress efficiently that the light emitted from the said LED leaks. Moreover, since the 1st opposing part and the 2nd opposing part can move to the direction which opens mutually, it is easy to attach to a light-guide plate.
  • a white resist may be applied to a surface of the LED mounting portion, the first facing portion, and the second facing portion that faces the light guide plate.
  • the white resist preferably has a reflectance of 70% or more, more preferably 80% or more. A higher reflectance is preferable because more light can be reflected and the light utilization rate can be increased.
  • the white resist include a photoresist formed by a photolithography method, a screen printing resist, or the like.
  • At least surfaces of the first facing portion and the second facing portion that are in contact with the light guide plate may be roughened.
  • At least one of the first facing portion and the second facing portion facing the light guide plate may be formed such that a gap is opened between the end portion side and the light guide plate.
  • the first counter portion or the A column portion for maintaining a gap between the second facing portion and the light guide plate may be formed.
  • the column portion may be a columnar one that makes point contact with the light guide plate or a plate-like one that makes line contact with the light guide plate.
  • a liquid crystal display apparatus in which a liquid crystal panel unit is disposed on the front side of the backlight can be cited.
  • the present invention since the first facing portion and the second facing portion are in contact with the light guide plate, leakage of light emitted from the LED can be suppressed. Moreover, since the heat generated from the LED can be efficiently dissipated, it is possible to suppress light leakage due to deformation of the light guide plate and a decrease in light emission efficiency due to the LED itself becoming a high temperature. Can be suppressed.
  • FIG. 1 is an exploded perspective view of an example of a liquid crystal display device including a backlight according to the present invention.
  • FIG. It is sectional drawing of the liquid crystal display device shown in FIG. It is a front view of the light source unit used for the backlight concerning this invention. It is sectional drawing of the light source unit shown in FIG. It is a front view which shows arrangement
  • 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 disposed to face the array substrate 611, and liquid crystal filled between the array substrate and the counter substrate.
  • 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 array substrate 611 and 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.
  • the bezel 7 includes a rectangular opening window 70 formed so as not to hide the image display area of the liquid crystal panel unit 6, a presser 71 that presses the liquid crystal panel unit 6 from the front side, and a rear side from the edge of the presser 71.
  • the cover part 72 which protrudes to the side and covers the edge part 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 reflection sheet 103 is disposed inside the backlight chassis 10 in addition to the light guide plate 2, the light source unit 3, and the optical sheet 4 described above. 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 protrudes from a bottom 100 having a rectangular shape in plan view and four sides of the bottom 100. And a side wall 101.
  • the backlight chassis 10 can also be referred to as a frame member having a bottom 100.
  • a reflective sheet 103, a light guide plate 2, and an optical sheet 4 are arranged in this order on the bottom 100 of the backlight chassis 10. Further, the light source unit 3 is fixed inside the portion of the side wall 101 of the backlight chassis 10 that protrudes from the two long sides of the bottom 100.
  • 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 exit surface 21, and one of the longitudinal side surfaces is configured as a light receiving surface 22 that receives light from the light source unit 3.
  • the light guide plate 2 when the incident angle exceeds the critical angle, the light is totally reflected and propagated into the light guide plate 2.
  • a texture pattern (not shown) is formed that reflects the totally reflected light so as to rise toward the light exit surface 21.
  • a lens-shaped pattern or a pattern printed with an ink having a higher refractive index than the light guide plate material is generally used.
  • the light that hits the embossed pattern changes its propagation angle when reflected (becomes smaller than the critical angle) and rises toward the exit slope 21.
  • the embossed pattern is provided with a phosphor. When the light rises in the embossed pattern, the light is excited by the phosphor and emitted from the light exit surface 21 as wavelength-converted light.
  • the backlight 1 is a lighting device that emits planar light, and the planar light preferably has a highly uniform luminance distribution. Therefore, the uniformity of the luminance distribution is controlled by adjusting the coverage of the embossed pattern.
  • the embossed pattern is a dot-like pattern having both a size and a thickness of 100 ⁇ m to 500 ⁇ m, and the coverage (the ratio occupied by the embossed pattern per unit area) is controlled from 0% to 100%.
  • the 1st opposing part 51 which opposes the light emission surface 21 is arrange
  • the light source unit 3 includes a long LED substrate 5 disposed to face the light receiving surface 22 and a plurality (eight) LEDs 31 arranged in a row on the LED substrate 5.
  • the LEDs 31 are arranged at equal intervals, but may be an arrangement in which the intervals are partially changed.
  • the light source unit 3 is attached to the backlight chassis 10, and the light emitted from the LEDs 31 enters from the light receiving surface 22 of the light guide plate 2. Details of the light source unit 3 and the LED substrate 5 will be described later.
  • 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. 3 is a front view of the light source unit used in the backlight according to the present invention
  • FIG. 4 is a sectional view of the light source unit shown in FIG. 3
  • FIG. 5 is a front view showing the arrangement of the backlight according to the present invention. It is.
  • the light source unit 3 includes eight LEDs 31 and an LED substrate 5 on which the eight LEDs 31 are mounted linearly.
  • the LED substrate 5 has a U-shaped cross section, and faces the first opposing portion 51 having a rectangular parallelepiped shape facing the front surface of the light guide plate 2 and the back surface 23 of the light guide plate 2.
  • a rectangular parallelepiped shaped second opposing portion 52, an LED mounting portion 53 on which the long side of the first opposing portion 51 and the long side of the second opposing portion 52 are connected and the LED 31 is mounted are provided.
  • the first facing portion 51 and the second facing portion 52 have a shape erected from one main surface of the LED mounting portion 53. Then, eight LEDs 31 are arranged at equal intervals in a portion sandwiched between the first facing portion 51 and the second facing portion 52 of the LED mounting portion 53.
  • a solder resist is formed as a protective film of the LED substrate 5 on the inner wall surfaces of the first facing portion 51 and the second facing portion 52 and the mounting surface of the LED mounting portion 53.
  • the solder resist is applied by a conventionally well-known method such as a photolithography method or a screen printing method.
  • the light source unit 3 and the light guide plate 2 are disposed inside a bottomed frame-like backlight chassis 10.
  • the light source unit 3 is disposed along the long side of the bottom portion 100 of the backlight chassis 10, the LED 31 mounted on the connecting portion 53 and the light receiving surface 22 face each other, and the first facing portion 51 emits light.
  • the surface 21 and the second facing portion 52 are disposed to face the surface opposite to the light exit surface 21. That is, the side surface on the long side of the light guide plate 2 is disposed so as to be surrounded by the light source unit 3.
  • the LED substrate 5 is arranged such that the inner wall surface of the first facing portion 51 and the inner wall surface of the second facing portion 52 are in contact with the light exit surface 21 and the back surface 23 of the light guide plate 2, respectively. Has been. By being formed in this way, light emitted from the LED 31 can be prevented from leaking from the gap between the LED substrate 5 and the light guide plate 2.
  • the light emitted from the LED 31 is prevented from leaking, it is possible to suppress the occurrence of uneven brightness in the planar light emitted from the backlight 1.
  • the light emitted from the LED 31 can be efficiently incident on the light receiving surface 22 of the light guide plate 2, the light use efficiency can be increased, and the energy consumed when the LED 31 emits light. (Electric power) can be reduced.
  • the LED board 5 is disposed in contact with the backlight chassis 10, heat from the LEDs 31 is transmitted to the backlight chassis 10 through the LED board 5. Since the LED substrate 5 is disposed so as to surround the LED 31, heat generated from the LED 31 is efficiently conducted to the LED substrate 5. Further, since the shape of the LED substrate 5 is U-shaped in cross section, it is possible to increase the area in contact with the bottom 100, the side wall 101, and the chassis case 102 of the backlight chassis 10. 5, the heat radiation to the backlight chassis 10 and the chassis case 102 is efficiently performed.
  • the length of the LED board 5 is formed shorter than the length of the light receiving surface 22 of the light-guide plate 2 in the longitudinal direction, it is not limited to this, It is the same length as the light receiving surface 22. Alternatively, it may be longer than the length of the light receiving surface 22 in the longitudinal direction.
  • the first facing portion 51 and the LED mounting portion 53, and the second facing portion 52 and the LED mounting portion 53 are described as an example, but the present invention is not limited thereto. It is good also as a structure which makes each separately and combines.
  • segmented into a longitudinal direction may be sufficient. Since the structure can be divided, the influence of the error of the member is reduced, so that the inspection process for manufacturing can be reduced.
  • a glass epoxy substrate is often used as a substrate for mounting LEDs.
  • Glass epoxy substrates have low thermal conductivity.
  • an LED substrate is manufactured with a glass epoxy substrate, the heat dissipation efficiency is low, and it may be difficult to efficiently suppress the temperature increase of the LED 31. Therefore, in the backlight of the present invention, an aluminum substrate is used in order to efficiently release the heat generated by the LED 31.
  • the configuration and shape are the same as those of the backlight according to the first embodiment, and detailed description thereof is omitted.
  • the thermal conductivity is 0.35 W / mK, but in the case of an aluminum substrate, it is 236 W / mK and has a thermal conductivity of about 500 times. .
  • fever which LED31 emits can be thermally radiated efficiently by utilizing the board
  • the thermal conductivity of copper is 390 W / mK, which is about 1.7 times that of aluminum, and the heat dissipation efficiency can be further increased by using a copper substrate.
  • the whole need not be aluminum or copper, and may be a substrate on which aluminum, copper, or a metal film having a higher thermal conductivity is formed on the surface of resin equipment. In that case, it is preferable that the structure facilitates heat conduction between the front surface and the back surface.
  • FIG. 6 is a front view showing a state before processing the LED substrate
  • FIG. 7 is a sectional view of the LED substrate shown in FIG. 6
  • FIG. 8 is a sectional view of the LED substrate after processing.
  • the LED substrate 5B is a substrate having a complicated shape such as a U-shaped cross section, and the manufacturing is simplified by the following method.
  • the unprocessed LED substrate 50b is a single metal substrate, the LED mounting portion 53b at the center, the first facing portion 51b and the LED mounting portion 53 on both sides in the short direction.
  • the second facing portions 52b are respectively disposed.
  • a notch 501 having a triangular cross section (right isosceles triangle) is formed in a portion between the LED mounting portion 53b and the first facing portion 51b.
  • a notch 502 having the same shape as the notch 501 is formed between the LED mounting portion 53b and the second facing portion 52b.
  • the first opposing portion 51b of the LED substrate 50 before processing is raised with the notch 501 as the center, and the second opposing portion 52b is raised with the notch 502 as the center, so that the cross section as shown in FIG. A U-shaped LED substrate 5B can be formed.
  • the LED substrate 5B is formed by a cutting process for forming a notch in a single metal substrate and a process (press process) for raising the first facing part 51b and the second facing part 52b. Since it can be manufactured, processing is easy, and it is possible to reduce the time and labor required for manufacturing. In addition, since the manufactured LED board 5B can rotate the 1st opposing part 51b and the 2nd opposing part 52b centering on notch 501,502, the attachment to the light-guide plate 2 becomes easy. Moreover, since the shape after manufacture is the same as the LED board of 1st Embodiment and 2nd Embodiment, about the effect, it is the same as 1st Embodiment and 2nd Embodiment.
  • a solder resist for protecting the LED substrate 5 is formed on the inner wall surfaces of the first facing portion 51, the second facing portion 52, and the LED mounting portion 53 of the LED substrate 5.
  • the LED substrate 5 is attached to the light guide plate 2 so as to surround the end portion on which the light receiving surface 22 is formed from three directions, and at least the first facing surface 51 and the second surface.
  • the facing surface 52 is disposed in contact with the light exit surface 21 and the back surface 23 of the light guide plate 2.
  • the light emitted from the LED 31 or the light propagated through the light guide plate 2 may be reflected by the first facing surface 51 or the second facing surface 52. Moreover, the light reflected by the light receiving surface 22 or the light propagated through the light guide plate 2 may be emitted from the light receiving surface 22. In this case, the light is incident on the surface on which the LED 31 of the LED mounting portion 53 is mounted. .
  • a solder resist is formed on the first opposing surface 51, the second opposing surface 52 and the inner wall surface of the LED mounting portion 53 of the LED substrate 5 on which light is incident, and the light is not reflected depending on the color of the solder resist. As a result, the light use efficiency decreases. Therefore, when a white solder resist that efficiently reflects light is used on the inner wall surface of the LED substrate 5, the light absorbed by the LED substrate 5 can be reduced and the light utilization rate can be increased.
  • a highly reflective white solder resist having a reflectance of 70% or more the amount of light absorbed by the LED substrate 5 is reduced, that is, the utilization factor of light emitted from the LED 31 is improved.
  • a white solder resist there are also a highly reflective white solder resist having a reflectance of 80% or more and a highly reflective white solder resist having a reflectance of 90% or more, and the light absorbed by using these highly reflective white resists. It is possible to reduce the ratio of light and to further improve the light use efficiency.
  • a solder resist having a high reflectance on the inner wall surface of the LED substrate 5 it is possible to increase the light use efficiency and reduce the energy (electric power) consumed when the LED 31 emits light. Is possible.
  • a white reflective layer is printed on the upper surface of a normal solder resist. May be formed. Even when the reflective layer is formed, it is possible to obtain the same light utilization efficiency as that for forming the highly reflective white solder resist.
  • FIG. 9 is an enlarged cross-sectional view of the LED substrate portion of the backlight according to the present invention.
  • the backlight 1 shown in FIG. 9 has the same configuration as that of the backlight 1 shown in FIG. 2 and the like except that the LED substrate 5C is different. Description is omitted.
  • the light incident on the inside of the light guide plate 2 propagates (diffuses) inside the light guide plate 2 while being repeatedly reflected.
  • the incident angle is determined by the refractive index of the light guide plate 2 and the refractive index of air.
  • Light incident at a larger angle is totally reflected at the boundary surface (side surface of the light guide plate 2), and the total amount of light propagates inside the light guide plate 2.
  • the LED substrate is a member that does not easily transmit light
  • the LED substrate 5C has a constant reflectance at the portion of the light guide plate 2 that contacts the LED substrate, but reflected light corresponding to the reflectance is generated. The remaining light that has not been reflected is absorbed by the LED substrate, and the light use efficiency decreases.
  • the contact area of the inner wall surface 511 of the first facing portion 51c, the inner wall surface 521 of the second facing portion 52c, that is, the surface facing the light guide plate 2 is reached. In order to reduce this, the surface is roughened.
  • the inner wall surface 511 of the first facing portion 51c and the inner wall surface 521 of the second facing portion 52c are roughened, so that the inner wall surface 511, the light exit surface 21, the inner wall surface 521, An air layer is formed between the back surface 23.
  • the incident angles of the light propagated in the light guide plate 2 and incident on the first facing portion 51c and the second facing portion 52c are larger than the critical angles determined by the respective refractive indexes of the light guide plate 2 and air.
  • the light is totally reflected by the light guide plate 2.
  • the light absorbed by the LED substrate 5C can be reduced, and the light use efficiency can be improved.
  • the inner wall surface of the 1st opposing part 51c and the 2nd opposing part 52c is roughened only the part facing the light emission surface 21 and the back surface 23 of the light-guide plate 2 (contact).
  • only the facing (contact) portion is roughened, so that the light emitted from the LED 31 and reaching the light receiving surface 22 reaches the first facing portion 51c or the second facing portion 52c. Reflected uniformly by the inner wall surfaces 511 and 521.
  • FIG. 10A is a cross-sectional view showing another example of the LED substrate
  • FIG. 10B is an enlarged cross-sectional view showing another example of the LED substrate.
  • the inner wall surface 511 of the first facing portion 51c and the inner wall surface 521 of the second facing portion 52c of the LED substrate 5C are in contact with the light emitting surface 21 and the back surface 23 only in the vicinity of the light receiving surface 22.
  • tip of the inner wall surface 511 and the inner wall surface 521 is formed so that it may leave
  • the light receiving surface 22 and the LED substrate 5C are in close contact with each other, and light leakage from the gap between the light receiving surface 22 and the LED substrate 5C is suppressed. Further, since an air layer is formed between the inner wall surface 511 and the light exit surface 21, and between the inner wall surface 521 and the rear surface 23, the light propagated inside the light guide plate 2 is totally reflected inside the light guide plate 2. Therefore, a decrease in light utilization efficiency can be suppressed.
  • support columns 512 and 522 that contact the light guide plate 2 may be formed on the light receiving surface 511 and the light receiving surface 521.
  • pillar part 512 is a column-shaped support
  • pillar part 522 is a plate-shaped support
  • the LED substrate 5 can be stably attached to the light guide plate 2 by providing the support columns 512 and 522.
  • pillar part 512 may be a plate-shaped support
  • pillar part 522 may be a column-shaped support
  • both may be a column shape, or both may be a column-shaped support
  • the contact area between the column part 512 and the light exit surface 21 and between the column part 522 and the back surface 23 is very small, it is difficult to affect the total reflection of the light propagated inside the light guide plate 2. Therefore, by providing the column portions 512 and 522, it is possible to stably attach the LED substrate 5C to the light guide plate 2, and it is possible to suppress a decrease in light utilization efficiency.
  • the column shape and the plate-like shape have been described as examples of the shape of the column portions 512 and 522, it is not limited to this, and a column with a small contact area with the surface of the light guide plate 2 is widely used. It is possible to adopt.
  • a double-sided pressure-sensitive adhesive sheet is used for fixing the LED substrate 5 and the backlight chassis 10.
  • the double-sided pressure-sensitive adhesive sheet is mostly formed of a resin, has a low thermal conductivity, and often becomes a thermal resistance between the LED substrate 5 and the backlight chassis 10.
  • the double-sided adhesive sheet between the LED substrate 5 and the backlight chassis 10 becomes a thermal resistance, and heat conduction is not performed so much.
  • the heat conducted from the LED 31 to the LED substrate 5 decreases, the temperature of the LED 31 increases, and the light emission efficiency of the LED 31 decreases.
  • heat is also conducted to the light guide plate 2 disposed close to the LED substrate 5, and the light guide plate 2 may be warped due to thermal deformation. It can also be a cause.
  • a double-sided pressure-sensitive adhesive sheet that has been often used conventionally has a thermal conductivity of 0.1 W / mK and a thermal resistance. Therefore, by using the heat conductive double-sided pressure-sensitive adhesive sheet having a heat conductivity of 1.0 W / mK, the heat dissipation efficiency is increased, and the temperature rise of the LED substrate 5 can be suppressed. Thereby, the temperature rise of LED31 can also be reduced and it can suppress that the luminous efficiency of LED31 falls. Moreover, since the temperature rise of the light-guide plate 2 can also be suppressed, it is possible to suppress light leakage that occurs when the light-guide plate 2 is warped. Further, by using a double-sided pressure-sensitive adhesive sheet having higher thermal conductivity, it is possible to further increase the heat radiation efficiency.
  • the LED substrate has the same length (width) in the short direction of the first facing portion and the length (width) in the short direction of the second facing portion, but is different.
  • the width of the second facing portion may be shorter than the width of the first facing portion.
  • the liquid crystal display device according to the present invention can be used for a television receiver, a PC monitor and the like.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Planar Illumination Modules (AREA)

Abstract

In order to suppress leakage of light from LEDs and decline in light emission efficiency of LEDs without increasing constituent members, a backlight comprises: a light-guide plate (2) which receives light from a light-receiving surface (22) and emits planar light from a light-emitting surface (21); and an LED substrate (5) which has a C-shaped cross section and includes an LED mounting part (53) having a plurality of LEDs (31) mounted thereon in rows, a first opposing part (51) and a second opposing part (52). The LED substrate (5) is attached to the light-guide plate (2) in such a way that the LED mounting part (53) opposes the light-receiving surface (22) and also the first opposing part (51) comes into contact with the light-emitting surface (21) and the second opposing part (52) comes into contact with a rear surface (23).

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、前記エッジライト方式のバックライトで、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、近年、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 with the edge light type backlight by improving the accuracy of the light guide plate and increasing the brightness of the LED used as the light source. In recent years, 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. ing.
　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、複数個のＬＥＤが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 are arranged side by side, receives light emitted from the light source unit from a light receiving surface on a side surface, and receives planar light from a light emitting surface of one main surface. An output light guide plate, an optical sheet disposed adjacent to the light exit surface of the light guide plate, and a reflection sheet 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.
　前記エッジライト方式のバックライトでは、前記ＬＥＤから出射された光を効率よく導光板に入射させるため、すなわち、前記ＬＥＤから出射された光が前記受光面から外れるのを抑制するため、前記導光板は前記受光面が前記ＬＥＤに近接するように配置されている。 In the edge light type backlight, the light guide plate is used to efficiently cause the light emitted from the LED to enter the light guide plate, that is, to prevent the light emitted from the LED from coming off the light receiving surface. Is arranged so that the light receiving surface is close to the LED.
　一方で、ＬＥＤのような半導体発光素子は入力する電流が大きくなると温度が上昇する特性を有している。前記受光面と前記ＬＥＤとを接近させすぎると、前記ＬＥＤの熱を放出することが難しくなり、温度が上昇し、発光効率が低下する。このＬＥＤの発光効率の低下によって、バックライトから出射される面状光の輝度むら、輝度低下等が発生し、前記バックライトの品質の低下の原因となっていた。 On the other hand, a semiconductor light emitting element such as an LED has a characteristic that the temperature rises when the input current increases. If the light receiving surface and the LED are too close together, it is difficult to release the heat of the LED, the temperature rises, and the light emission efficiency decreases. Due to the decrease in the light emission efficiency of the LED, uneven brightness of the planar light emitted from the backlight, a decrease in brightness, and the like have occurred, causing a decrease in the quality of the backlight.
　上述のような光漏れと、ＬＥＤの発熱による前記バックライトの品質低下を同時に抑制するため、ＬＥＤの熱を効率的に放熱する方法が提案されている。このような、放熱方法を備えたバックライトについて、図面を参照して説明する。図１１は従来の熱対策を施したバックライトの断面図である。 In order to simultaneously suppress the light leakage as described above and the deterioration in the quality of the backlight due to the heat generated by the LED, a method of efficiently dissipating the heat of the LED has been proposed. A backlight provided with such a heat dissipation method will be described with reference to the drawings. FIG. 11 is a cross-sectional view of a conventional backlight with a countermeasure against heat.
　図１１に示すように、バックライト９１は、導光板９２と、ＬＥＤ９３１が列状に実装されたフィルム基板９３及び金属リフレクタ９４を備える光源９５と、光源９５を導光板９２に取り付けた状態でこれら収納保持する枠状フレーム９６及び面状フレーム９７とを備えている。そして、導光板９２の出光面には、複数の光学部材からなる光学シート９８が備えられている。 As shown in FIG. 11, the backlight 91 includes a light guide plate 92, a light source 95 including a film substrate 93 on which LEDs 931 are mounted in a row and a metal reflector 94, and a light source 95 attached to the light guide plate 92. A frame-like frame 96 and a planar frame 97 for storing and holding are provided. An optical sheet 98 made of a plurality of optical members is provided on the light exit surface of the light guide plate 92.
　また、フィルム基板９３のＬＥＤ９３１が実装されていない面には金属薄膜９３２及び軟質アルミシート９３３が取り付けられている。金属薄膜９３２及び軟質アルミシート９３３が枠状フレーム９６に押さえられているとともに、枠状フレーム９６と金属リフレクタ９４とが放熱用フィルムシート９０で取り付けられている（特開２００３－７６２８７号公報参照）。 Further, a metal thin film 932 and a soft aluminum sheet 933 are attached to the surface of the film substrate 93 where the LED 931 is not mounted. The metal thin film 932 and the soft aluminum sheet 933 are held by the frame-shaped frame 96, and the frame-shaped frame 96 and the metal reflector 94 are attached by a heat-dissipating film sheet 90 (see Japanese Patent Application Laid-Open No. 2003-76287). .
　フィルム基板９３に接触配置された金属薄膜９３２及び軟質アルミシート９３３を介し、ＬＥＤ９３１から発せられる熱を枠状フレーム９６に逃がすので、ＬＥＤ９３１から発せられた熱で導光板９２が加熱されたり、ＬＥＤ９３１自体の温度が上昇したりするのを抑制することができる。これにより、上述したような、ＬＥＤの熱によるバックライトの品質の低下を抑制することができる。 The heat generated from the LED 931 is released to the frame-shaped frame 96 through the metal thin film 932 and the soft aluminum sheet 933 disposed in contact with the film substrate 93, so that the light guide plate 92 is heated by the heat generated from the LED 931 or the LED 931 itself. It is possible to suppress the temperature from rising. Thereby, the deterioration of the quality of the backlight by the heat | fever of LED as mentioned above can be suppressed.
特開２００３－７６２８７号公報JP 2003-76287 A
　しかしながら、特開２００３－７６２８７号公報に記載のバックライト装置では、ＬＥＤ９３１より生じた熱はフィルム基板９３に伝わり金属薄膜９３２及び軟質アルミシート９３３を通じて枠状フレーム９６、放熱用フィルムシート９０、面状フレーム９７へと放熱をさせているが、部品間（例えば、金属薄膜９３２と枠状フレーム９６）には、空気層が形成されてしまいやすく、放熱性の低下の原因となる場合がある。 However, in the backlight device described in Japanese Patent Application Laid-Open No. 2003-76287, the heat generated from the LED 931 is transmitted to the film substrate 93 and is transmitted through the metal thin film 932 and the soft aluminum sheet 933 to the frame frame 96, the heat dissipation film sheet 90, and the planar shape. Although heat is radiated to the frame 97, an air layer is easily formed between components (for example, the metal thin film 932 and the frame-shaped frame 96), which may cause a decrease in heat dissipation.
　また、導光板９２を複数の部材（面状フレーム９７、枠状フレーム９６等）で固定し、光源９５と導光板９２とを近接配置しているため、熱膨張によって導光板９２が反りやすい。導光板９２が反ってしまうと、導光板９２の受光面とＬＥＤ９３１の発光面との光軸がずれ、光漏れが発生しやすくなる。また、光源９５と導光板９２とが接触しているため、ＬＥＤ９３１の熱により導光板９２が膨張すると、ＬＥＤ９３１を押しＬＥＤ９３１を破壊する場合もある。 In addition, since the light guide plate 92 is fixed by a plurality of members (planar frame 97, frame frame 96, etc.) and the light source 95 and the light guide plate 92 are disposed close to each other, the light guide plate 92 is likely to warp due to thermal expansion. When the light guide plate 92 is warped, the optical axes of the light receiving surface of the light guide plate 92 and the light emitting surface of the LED 931 are shifted, and light leakage is likely to occur. In addition, since the light source 95 and the light guide plate 92 are in contact with each other, when the light guide plate 92 expands due to the heat of the LED 931, the LED 931 may be pushed to destroy the LED 931.
　さらに、金属薄膜９３２、軟質アルミシート９３３、放熱用フィルムシート９０等、構成部材が多くなり、それだけ、製造にかかる時間と手間が増え、製造コストが高くなりやすい。 Furthermore, the number of constituent members such as the metal thin film 932, the soft aluminum sheet 933, the heat dissipation film sheet 90, and the like increases, so that the time and labor required for the production increase, and the production cost tends to increase.
　そこで本発明は、構成部材を増やすことなく、ＬＥＤからの光漏れや、ＬＥＤの発光効率の低下を抑制し、光利用効率の高いエッジライト方式のバックライト及びバックライトを用いた液晶表示装置を提供することを目的とする。 Therefore, the present invention suppresses light leakage from the LED and reduction of the light emission efficiency of the LED without increasing the number of components, and provides an edge light type backlight having high light utilization efficiency and a liquid crystal display device using the backlight. The purpose is to provide.
　上記目的を達成するため本発明は、側面の受光面から光が入射され、一主面の出光面より面状光を出射する導光板と、複数個のＬＥＤが列状に実装されたＬＥＤ実装部、前記ＬＥＤ実装部より突出し前記ＬＥＤを囲むように配置された第１対向部及び第２対向部を含む断面コの字状のＬＥＤ基板と、を有し、前記ＬＥＤ基板は、前記ＬＥＤ実装部が前記受光面と対向するとともに、前記第１対向部が前記出光面と、前記第２対向部が前記出光面の裏側の面と接触するように導光板に取り付けられているバックライトを提供する。 In order to achieve the above object, the present invention provides a light guide plate that receives light from a light receiving surface on a side surface and emits planar light from a light exit surface of one main surface, and an LED mounting in which a plurality of LEDs are mounted in a row. And an LED substrate having a U-shaped cross section including a first facing portion and a second facing portion that protrude from the LED mounting portion and surround the LED, and the LED substrate is mounted on the LED mounting surface. Provided is a backlight attached to the light guide plate such that the portion faces the light receiving surface, the first facing portion contacts the light exit surface, and the second facing portion contacts the back surface of the light exit surface. To do.
　この構成によると、前記ＬＥＤより出射された光が、前記導光板と他の部材との隙間から漏れるのを抑制することが可能である。また、前記バックライトの厚みを変えることなく、従来のものに対して、ＬＥＤ基板の大きさを大きくすることができるので、ＬＥＤから発せられる熱をＬＥＤ基板を介して、効率よく放熱することが可能である。 According to this configuration, it is possible to suppress light emitted from the LED from leaking through a gap between the light guide plate and another member. In addition, since the size of the LED substrate can be increased compared to the conventional one without changing the thickness of the backlight, heat generated from the LED can be efficiently radiated through the LED substrate. Is possible.
　これにより、前記ＬＥＤの温度の上昇を抑制することができ、前記ＬＥＤが高温になることによる発光効率の低下を抑えることができる。また、前記ＬＥＤから前記導光板に伝導する熱も少なくなるので、前記導光板の熱変形による反りの発生を抑えることができる。これにより、前記導光板の受光面の中心と、前記ＬＥＤの発光面の光軸とがずれることにより発生する、光漏れを抑制することが可能である。 Thereby, an increase in the temperature of the LED can be suppressed, and a decrease in luminous efficiency due to the LED becoming high temperature can be suppressed. Moreover, since the heat conducted from the LED to the light guide plate is reduced, it is possible to suppress the occurrence of warpage due to thermal deformation of the light guide plate. Thereby, it is possible to suppress light leakage that occurs when the center of the light receiving surface of the light guide plate is shifted from the optical axis of the light emitting surface of the LED.
　これらのことより、ＬＥＤの光利用率の低下を抑制し、光漏れによって発生するバックライトから出射される面状光の輝度むらを抑制することが可能である。また、ＬＥＤ基板で効率よく放熱することができるので、放熱用の部材を備えなくてもよく、それだけ、部材点数が増えるのを抑えることができ、小型化、軽量化に有利である。 For these reasons, it is possible to suppress a decrease in the light utilization rate of the LED, and to suppress unevenness in the brightness of the planar light emitted from the backlight caused by light leakage. In addition, since the LED substrate can efficiently dissipate heat, it is not necessary to provide a heat dissipating member, and accordingly, the increase in the number of members can be suppressed, which is advantageous for downsizing and weight reduction.
　上記構成において、前記ＬＥＤ基板は、金属材料で形成されていてもよい。 In the above configuration, the LED substrate may be formed of a metal material.
　この構成によると、前記ＬＥＤ基板の熱伝導率が高いので、前記ＬＥＤ及び前記導光板の温度上昇を抑えることができる。このことから、前記ＬＥＤの発光効率の低下を抑制し、前記導光板の熱変形による反りの発生をより効果的に抑えることができる。なお、ＬＥＤ基板を構成する金属材料として、熱伝導率の高いアルミニウム、銅等を挙げることができる。また、これら以外にも熱伝導率が高い金属を採用することができる。 According to this configuration, since the thermal conductivity of the LED substrate is high, an increase in temperature of the LED and the light guide plate can be suppressed. From this, the fall of the luminous efficiency of the said LED can be suppressed, and generation | occurrence | production of the curvature by the thermal deformation of the said light-guide plate can be suppressed more effectively. In addition, examples of the metal material constituting the LED substrate include aluminum and copper having high thermal conductivity. In addition to these, metals having high thermal conductivity can be employed.
　上記構成において、前記ＬＥＤ基板は、ノッチが形成された平板状の金属基板を折り曲げて作製されていてもよい。 In the above configuration, the LED substrate may be manufactured by bending a flat metal substrate on which a notch is formed.
　前記ＬＥＤ基板を製造するときに容易に製造することができるとともに、加工精度を高めることができ、前記第１対向部と導光板、前記第２対向部と導光板の隙間が発生しにくい。このことから、前記ＬＥＤから発せられた光が漏れるのを効率よく抑制することができる。また、第１対向部及び第２対向部が互いに開く方向に移動可能であるので、導光板に取り付けることが容易である。 The LED substrate can be easily manufactured and processing accuracy can be increased, and a gap between the first facing portion and the light guide plate and between the second facing portion and the light guide plate is hardly generated. From this, it can suppress efficiently that the light emitted from the said LED leaks. Moreover, since the 1st opposing part and the 2nd opposing part can move to the direction which opens mutually, it is easy to attach to a light-guide plate.
　上記構成において、前記ＬＥＤ実装部、前記第１対向部及び前記第２対向部の前記導光板と対向する面には、白色レジストが施されていてもよい。 In the above configuration, a white resist may be applied to a surface of the LED mounting portion, the first facing portion, and the second facing portion that faces the light guide plate.
　この構成によると、前記ＬＥＤから出射された光が直接、あるいは、前記導光板を伝導したのち、前記ＬＥＤ基板の表面で反射されるので、光の利用効率が高くなる。なお、白色レジストとして、反射率が、７０％以上のものが好ましく、８０%以上のものがより好ましい。反射率は高い方が多くの光を反射し光利用率を上げることができるので好ましい。白色レジストとしては、フォトリソグラフィー法、スクリーン印刷レジスト等で形成されたフォトレジストを挙げることができる。 According to this configuration, since the light emitted from the LED is reflected directly or after being conducted through the light guide plate, it is reflected on the surface of the LED substrate, so that the light utilization efficiency is increased. The white resist preferably has a reflectance of 70% or more, more preferably 80% or more. A higher reflectance is preferable because more light can be reflected and the light utilization rate can be increased. Examples of the white resist include a photoresist formed by a photolithography method, a screen printing resist, or the like.
　上記構成において、前記第１対向部及び前記第２対向部の少なくとも前記導光板と接触する面が、粗面化されていてもよい。 In the above configuration, at least surfaces of the first facing portion and the second facing portion that are in contact with the light guide plate may be roughened.
　前記第１対向部又は前記第２対向部の前記導光板と接触する面が粗面化されることで、空気の層が形成され、導光板内部を伝播する光が全反射可能な状態となる。これにより、導光板内部を伝播する光のＬＥＤ基板に吸収される量を低減し（光の損失を低減し）光利用効率を向上することが可能である。 By roughening the surface of the first facing portion or the second facing portion that contacts the light guide plate, an air layer is formed, and light propagating through the light guide plate can be totally reflected. . Thereby, it is possible to reduce the amount of light propagating through the inside of the light guide plate to be absorbed by the LED substrate (reduce light loss) and improve the light utilization efficiency.
　上記構成において、前記第１対向部又は前記第２対向部の少なくとも一方の前記導光板と対向する面は、端部側が前記導光板との間に隙間が開くように形成されていてもよい。このとき、前記第１対向部又は前記第２対向部の少なくとも一方の前記導光板と対向する面の前記導光板との間に隙間が形成されている部分には、前記第１対向部又は前記第２対向部と前記導光板との隙間を維持するための支柱部が形成されていてもよい。支柱部として、前記導光板と点接触する円柱状のものや、前記導光板と線接触する板状のものとすることができる。 In the above configuration, at least one of the first facing portion and the second facing portion facing the light guide plate may be formed such that a gap is opened between the end portion side and the light guide plate. At this time, in a portion where a gap is formed between the light guide plate of the surface facing the light guide plate of at least one of the first counter portion or the second counter portion, the first counter portion or the A column portion for maintaining a gap between the second facing portion and the light guide plate may be formed. The column portion may be a columnar one that makes point contact with the light guide plate or a plate-like one that makes line contact with the light guide plate.
　この構成によると、前記ＬＥＤ基板と前記導光板との間に空気の層が形成されるので、前記導光板内部を伝播した光が全反射できるようになる。これにより、光損失を低減することができ、光利用効率を向上することが可能である。 According to this configuration, since an air layer is formed between the LED substrate and the light guide plate, the light propagating through the light guide plate can be totally reflected. Thereby, light loss can be reduced and light utilization efficiency can be improved.
　上述したバックライトを利用する装置として、例えば、前記バックライトの前面側に液晶パネルユニットを配置した液晶表示装置を挙げることができる。 As an apparatus using the above-described backlight, for example, a liquid crystal display apparatus in which a liquid crystal panel unit is disposed on the front side of the backlight can be cited.
　本発明によると、第１対向部及び第２対向部が導光板と接していることで、ＬＥＤから出射された光が漏れるのを抑制することができる。また、ＬＥＤから発せられる熱を、効率的に放熱することができるので、導光板の変形による光漏れや、ＬＥＤ自体が高温になることによる発光効率の低下を抑制することができ、光利用率の低減を抑制することが可能である。 According to the present invention, since the first facing portion and the second facing portion are in contact with the light guide plate, leakage of light emitted from the LED can be suppressed. Moreover, since the heat generated from the LED can be efficiently dissipated, it is possible to suppress light leakage due to deformation of the light guide plate and a decrease in light emission efficiency due to the LED itself becoming a high temperature. Can be suppressed.
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本発明にかかる液晶表示装置の一例の分解斜視図である。1 is an exploded perspective view of an example of a liquid crystal display device including a backlight according to the present invention. FIG. 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. 本発明にかかるバックライトに用いられる光源ユニットの正面図である。It is a front view of the light source unit used for the backlight concerning this invention. 図３に示す光源ユニットの断面図である。It is sectional drawing of the light source unit shown in FIG. 本発明にかかるバックライトの配置を示す正面図である。It is a front view which shows arrangement | positioning of the backlight concerning this invention. ＬＥＤ基板の加工前の状態を示す正面図である。It is a front view which shows the state before the process of a LED board. 図６に示すＬＥＤ基板の断面図である。It is sectional drawing of the LED board shown in FIG. 加工後のＬＥＤ基板の断面図である。It is sectional drawing of the LED board after a process. 本発明にかかるバックライトの他の例の拡大断面図である。It is an expanded sectional view of the other example of the backlight concerning this invention. ＬＥＤ基板の他の例を示す断面図である。It is sectional drawing which shows the other example of an LED board. ＬＥＤ基板の他の例を示す断面図である。It is sectional drawing which shows the other example of an LED board. 従来の熱対策を施したバックライトの断面図である。It is sectional drawing of the backlight which gave the conventional heat countermeasure.
　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。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. The liquid crystal panel 61 includes an array substrate 611, a counter substrate 612 disposed to face the array substrate 611, and liquid crystal filled between the array substrate and the counter substrate.
　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と対向基板６１２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 array substrate 611 and 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。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. The bezel 7 includes a rectangular opening window 70 formed so as not to hide the image display area of the liquid crystal panel unit 6, a presser 71 that presses the liquid crystal panel unit 6 from the front side, and a rear side from the edge of the presser 71. The cover part 72 which protrudes to the side and covers the edge part 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１０３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)
Details of the backlight according to the present invention will be described. As shown in FIG. 2, in the backlight 1, a reflection sheet 103 is disposed inside the backlight chassis 10 in addition to the light guide plate 2, the light source unit 3, and the optical sheet 4 described above. 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の四辺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 protrudes from a bottom 100 having a rectangular shape in plan view and four sides of the bottom 100. And a side wall 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には、反射シート１０３、導光板２、光学シート４が順に重ねて配置されている。また、バックライトシャーシ１０の側壁部１０１のうち、底部１００の２つの長辺より突出する部分の内側に、光源ユニット３が固定されている。 A reflective sheet 103, a light guide plate 2, and an optical sheet 4 are arranged in this order on the bottom 100 of the backlight chassis 10. Further, the light source unit 3 is fixed inside the portion of the side wall 101 of the backlight chassis 10 that protrudes from the two long sides of the bottom 100.
　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、長手方向の側面のうち一方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。導光板２の内部において、光は入射角が臨界角を超えると全反射し、導光板２内に伝播される。導光板２の出光面２２と反対側の面（裏面２３とする）には、全反射する光を出光面２１に向かって立ち上げるように反射するシボパターン（不図示）が形成されている。 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 exit surface 21, and one of the longitudinal side surfaces is configured as a light receiving surface 22 that receives light from the light source unit 3. Inside the light guide plate 2, when the incident angle exceeds the critical angle, the light is totally reflected and propagated into the light guide plate 2. On the surface opposite to the light exit surface 22 of the light guide plate 2 (referred to as the back surface 23), a texture pattern (not shown) is formed that reflects the totally reflected light so as to rise toward the light exit surface 21.
　このようなシボパターンにはレンズ形状のものや導光板材料よりも高い屈折率のインクで印刷されたもの等が一般的に用いられている。このシボパターンに当った光は反射されるときに伝播する角度が変わり（臨界角よりも小さくなり）、出斜面２１に向かって立ち上がる。シボパターンには蛍光体が備えられており、光はシボパターンで立ち上がるとき、蛍光体によって励起され、波長変換された光として出光面２１より出射される。 For such a texture pattern, a lens-shaped pattern or a pattern printed with an ink having a higher refractive index than the light guide plate material is generally used. The light that hits the embossed pattern changes its propagation angle when reflected (becomes smaller than the critical angle) and rises toward the exit slope 21. The embossed pattern is provided with a phosphor. When the light rises in the embossed pattern, the light is excited by the phosphor and emitted from the light exit surface 21 as wavelength-converted light.
　バックライト１は面状光を出射する照明装置であり、面状光が均一性の高い輝度分布であることが好ましい。そのため、シボパターンの被覆率を調整することで、輝度分布の均一性を制御している。なお、シボパターンは点状で、大きさ、厚みともに１００μｍ～５００μｍのものを挙げることができ、被覆率（単位面積当たりのシボパターンが占める割合）は、０％～１００％で制御される。 The backlight 1 is a lighting device that emits planar light, and the planar light preferably has a highly uniform luminance distribution. Therefore, the uniformity of the luminance distribution is controlled by adjusting the coverage of the embossed pattern. Note that the embossed pattern is a dot-like pattern having both a size and a thickness of 100 μm to 500 μm, and the coverage (the ratio occupied by the embossed pattern per unit area) is controlled from 0% to 100%.
　なお、裏面２３のＬＥＤ基板５の後述する第２対向部５２が対向する部分では、光がシボパターンで立ち上がっても、出光面２１と対向する第１対向部５１が配置されているので、シボパターンによって立ち上げる必要がない。そのため、裏面２３のＬＥＤ基板５の第２対向部５２が対向する部分では、シボパターンが形成されていない。 In addition, in the part which the 2nd opposing part 52 mentioned later of the LED board 5 of the back surface 23 opposes, even if light stands | starts up by a grain pattern, the 1st opposing part 51 which opposes the light emission surface 21 is arrange | positioned. There is no need to start up with patterns. Therefore, a wrinkle pattern is not formed in the portion of the back surface 23 where the second facing portion 52 of the LED substrate 5 faces.
　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基板５と、ＬＥＤ基板５上に列状に配列された複数個（８個）のＬＥＤ３１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、光源ユニット３がバックライトシャーシ１０に取り付けられており、ＬＥＤ３１から出射された光は、導光板２の受光面２２より入射する。なお、光源ユニット３及びＬＥＤ基板５の詳細については後述する。 The light source unit 3 includes a long LED substrate 5 disposed to face the light receiving surface 22 and a plurality (eight) LEDs 31 arranged in a row on the LED substrate 5. 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 light source unit 3 is attached to the backlight chassis 10, and the light emitted from the LEDs 31 enters from the light receiving surface 22 of the light guide plate 2. Details of the light source unit 3 and the LED substrate 5 will be described later.
　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.
　本発明にかかるバックライトに用いられる光源ユニットの詳細について新たな図面を参照して説明する。図３は本発明にかかるバックライトに用いられる光源ユニットの正面図であり、図４は図３に示す光源ユニットの断面図であり、図５は本発明にかかるバックライトの配置を示す正面図である。 Details of the light source unit used in the backlight according to the present invention will be described with reference to a new drawing. 3 is a front view of the light source unit used in the backlight according to the present invention, FIG. 4 is a sectional view of the light source unit shown in FIG. 3, and FIG. 5 is a front view showing the arrangement of the backlight according to the present invention. It is.
　図３、図４に示すように、光源ユニット３は８個のＬＥＤ３１と、８個のＬＥＤ３１が直線状に実装されるＬＥＤ基板５とを含む構成となっている。そして、ＬＥＤ基板５はコの字形状の断面を有しており、導光板２の前面と対向して配置される直方体形状の第１対向部５１と、導光板２の裏面２３と対向して配置される直方体形状の第２対向部５２と、第１対向部５１の長辺と第２対向部５２の長辺とを連結し、ＬＥＤ３１が実装されるＬＥＤ実装部５３とを備えている。 As shown in FIGS. 3 and 4, the light source unit 3 includes eight LEDs 31 and an LED substrate 5 on which the eight LEDs 31 are mounted linearly. The LED substrate 5 has a U-shaped cross section, and faces the first opposing portion 51 having a rectangular parallelepiped shape facing the front surface of the light guide plate 2 and the back surface 23 of the light guide plate 2. A rectangular parallelepiped shaped second opposing portion 52, an LED mounting portion 53 on which the long side of the first opposing portion 51 and the long side of the second opposing portion 52 are connected and the LED 31 is mounted are provided.
　また、図３、図４に示すように、第１対向部５１及び第２対向部５２はＬＥＤ実装部５３の一方の主面より立設する形状を有している。そして、ＬＥＤ実装部５３の第１対向部５１及び第２対向部５２とで挟まれた部分に、８個のＬＥＤ３１が等間隔に並んで配置されている。第１対向部５１、第２対向部５２の内壁面及びＬＥＤ実装部５３の実装面とは、ＬＥＤ基板５の保護膜としてソルダレジストが形成されている。なお、ソルダレジストは、フォトリソグラフィー法、スクリーン印刷法等、従来、周知の方法で施される。 Further, as shown in FIGS. 3 and 4, the first facing portion 51 and the second facing portion 52 have a shape erected from one main surface of the LED mounting portion 53. Then, eight LEDs 31 are arranged at equal intervals in a portion sandwiched between the first facing portion 51 and the second facing portion 52 of the LED mounting portion 53. A solder resist is formed as a protective film of the LED substrate 5 on the inner wall surfaces of the first facing portion 51 and the second facing portion 52 and the mounting surface of the LED mounting portion 53. The solder resist is applied by a conventionally well-known method such as a photolithography method or a screen printing method.
　図１、２、５等に示すように、光源ユニット３及び導光板２は、有底枠状のバックライトシャーシ１０の内部に配置される。光源ユニット３は、バックライトシャーシ１０の底部１００の長辺に沿うように配置されるとともに、連結部５３に実装されたＬＥＤ３１と受光面２２とが対向し、さらに、第１対向部５１が出光面２１と、第２対向部５２が出光面２１の反対側の面と対向する配置される。すなわち、導光板２の長辺側の側面は、光源ユニット３に囲まれるように配置される。 As shown in FIGS. 1, 2, 5 and the like, the light source unit 3 and the light guide plate 2 are disposed inside a bottomed frame-like backlight chassis 10. The light source unit 3 is disposed along the long side of the bottom portion 100 of the backlight chassis 10, the LED 31 mounted on the connecting portion 53 and the light receiving surface 22 face each other, and the first facing portion 51 emits light. The surface 21 and the second facing portion 52 are disposed to face the surface opposite to the light exit surface 21. That is, the side surface on the long side of the light guide plate 2 is disposed so as to be surrounded by the light source unit 3.
　また、図２に示すように、ＬＥＤ基板５は、第１対向部５１の内壁面及び第２対向部５２の内壁面は、それぞれ、導光板２の出光面２１及び裏面２３と接触して配置されている。このように形成されていることで、ＬＥＤ３１より出射された光がＬＥＤ基板５と導光板２の隙間から漏れるのを抑制することができる。 As shown in FIG. 2, the LED substrate 5 is arranged such that the inner wall surface of the first facing portion 51 and the inner wall surface of the second facing portion 52 are in contact with the light exit surface 21 and the back surface 23 of the light guide plate 2, respectively. Has been. By being formed in this way, light emitted from the LED 31 can be prevented from leaking from the gap between the LED substrate 5 and the light guide plate 2.
　以上のことより、ＬＥＤ３１から出射された光が漏れるのを抑制するので、バックライト１から出射される面状光に輝度むらが発生するのを抑制することができる。また、光漏れを抑えることから、ＬＥＤ３１から出射された光を導光板２の受光面２２に効率よく入射させることができ光の利用効率を高めることができ、ＬＥＤ３１が発光するときに消費するエネルギ（電力）を低減することが可能である。 From the above, since the light emitted from the LED 31 is prevented from leaking, it is possible to suppress the occurrence of uneven brightness in the planar light emitted from the backlight 1. In addition, since light leakage is suppressed, the light emitted from the LED 31 can be efficiently incident on the light receiving surface 22 of the light guide plate 2, the light use efficiency can be increased, and the energy consumed when the LED 31 emits light. (Electric power) can be reduced.
　また、ＬＥＤ基板５はバックライトシャーシ１０と接触して配置されているので、ＬＥＤ３１からの熱がＬＥＤ基板５を介して、バックライトシャーシ１０に伝達される。ＬＥＤ基板５はＬＥＤ３１を囲むように配置されているので、ＬＥＤ３１から発せられる熱は、効率よくＬＥＤ基板５に伝導される。また、ＬＥＤ基板５の形状が断面コの字型であることから、バックライトシャーシ１０の底部１００、側壁部１０１及びシャーシケース１０２とに接触する面積を大きくすることが可能であるので、ＬＥＤ基板５から、バックライトシャーシ１０及びシャーシケース１０２への放熱が効率よくおこなわれる。 In addition, since the LED board 5 is disposed in contact with the backlight chassis 10, heat from the LEDs 31 is transmitted to the backlight chassis 10 through the LED board 5. Since the LED substrate 5 is disposed so as to surround the LED 31, heat generated from the LED 31 is efficiently conducted to the LED substrate 5. Further, since the shape of the LED substrate 5 is U-shaped in cross section, it is possible to increase the area in contact with the bottom 100, the side wall 101, and the chassis case 102 of the backlight chassis 10. 5, the heat radiation to the backlight chassis 10 and the chassis case 102 is efficiently performed.
　このことから、ＬＥＤ３１自体が高温になるのを抑制することができ、ＬＥＤ３１の熱による発光効率の低下が抑制される。また、ＬＥＤ３１から導光板２に伝達される熱を低減することができるので、導光板２の変形（膨張、反り）の発生を抑えることができるので、導光板２の受光面２２の軸とＬＥＤ３１の中心軸とのずれによる光漏れの発生を抑えることができる。 From this, it can suppress that LED31 itself becomes high temperature, and the fall of the luminous efficiency by the heat | fever of LED31 is suppressed. Moreover, since the heat transmitted from the LED 31 to the light guide plate 2 can be reduced, the occurrence of deformation (expansion and warpage) of the light guide plate 2 can be suppressed, so that the axis of the light receiving surface 22 of the light guide plate 2 and the LED 31 can be suppressed. It is possible to suppress the occurrence of light leakage due to the deviation from the central axis.
　これにより、同じ輝度を得るために高輝度、すなわち、高温化しやすいＬＥＤを用いることができるので、ＬＥＤの数を減らすことも可能である。また、ＬＥＤ基板５を大きくし、ＬＥＤ３１から発せられる熱をＬＥＤ基板５で効率よく放熱することができるので、放熱のための部材を追加しなくてもよく、部材点数が増加しないので、小型化、軽量化に有利である。 Thereby, in order to obtain the same luminance, it is possible to use LEDs with high luminance, that is, with high temperature easily, and therefore it is possible to reduce the number of LEDs. Moreover, since the LED substrate 5 can be enlarged and the heat generated from the LED 31 can be efficiently radiated by the LED substrate 5, it is not necessary to add a member for heat dissipation, and the number of members does not increase, so the size is reduced. It is advantageous for weight reduction.
　なお、ＬＥＤ基板５の長さは、導光板２の受光面２２の長手方向の長さよりも短く形成されているが、これに限定されるものではなく、受光面２２と同じ長さであってもよいし、受光面２２の長手方向の長さよりも長くてもよい。また、ＬＥＤ基板５では、第１対向部５１とＬＥＤ実装部５３、第２対向部５２とＬＥＤ実装部５３とが一体で形成されているものを例に説明しているが、それに限定されるものではなく、それぞれ、別体で作成し、組み合わせる構成としてもよい。また、長手方向に分割可能な構成であってもよい。分割可能な構成であることで、部材の誤差の影響が小さくなるので製造にかかる検査工程を減らすことが可能である。 In addition, although the length of the LED board 5 is formed shorter than the length of the light receiving surface 22 of the light-guide plate 2 in the longitudinal direction, it is not limited to this, It is the same length as the light receiving surface 22. Alternatively, it may be longer than the length of the light receiving surface 22 in the longitudinal direction. In the LED substrate 5, the first facing portion 51 and the LED mounting portion 53, and the second facing portion 52 and the LED mounting portion 53 are described as an example, but the present invention is not limited thereto. It is good also as a structure which makes each separately and combines. Moreover, the structure which can be divided | segmented into a longitudinal direction may be sufficient. Since the structure can be divided, the influence of the error of the member is reduced, so that the inspection process for manufacturing can be reduced.
（第２の実施形態）
　本発明にかかるバックライトの他の例について説明する。通常、ＬＥＤを実装する基板として、ガラスエポキシ基板を用いることが多い。ガラスエポキシ基板は熱伝導率が低くい。ガラスエポキシ基板でＬＥＤ基板を作製すると、放熱効率が低く、ＬＥＤ３１の温度上昇を効率的に抑制するのが難しい場合がある。そこで、本発明のバックライトでは、ＬＥＤ３１が発する熱を効率よく放出するため、アルミニウム製の基板を用いている。なお、構成、形状に関しては第１の実施形態のバックライトと同じであり詳細な説明は省略する。 (Second Embodiment)
Another example of the backlight according to the present invention will be described. Usually, a glass epoxy substrate is often used as a substrate for mounting LEDs. Glass epoxy substrates have low thermal conductivity. When an LED substrate is manufactured with a glass epoxy substrate, the heat dissipation efficiency is low, and it may be difficult to efficiently suppress the temperature increase of the LED 31. Therefore, in the backlight of the present invention, an aluminum substrate is used in order to efficiently release the heat generated by the LED 31. The configuration and shape are the same as those of the backlight according to the first embodiment, and detailed description thereof is omitted.
　ＬＥＤ基板をガラスエポキシ樹脂製の基板の場合、熱伝導率が０．３５Ｗ／ｍＫであるが、アルミニウム製の基板の場合、２３６Ｗ／ｍＫであり、約５００倍の熱伝導率を有している。このように、アルミニウム製の基板を利用することで、ＬＥＤ３１が発する熱を効率よく放熱することができる。これにより、バックライト１動作時のＬＥＤ３１の温度を低く抑えることができ、ＬＥＤ３１の発光効率の低下を抑えることができる。 In the case where the LED substrate is a glass epoxy resin substrate, the thermal conductivity is 0.35 W / mK, but in the case of an aluminum substrate, it is 236 W / mK and has a thermal conductivity of about 500 times. . Thus, the heat | fever which LED31 emits can be thermally radiated efficiently by utilizing the board | substrate made from aluminum. Thereby, the temperature of LED31 at the time of backlight 1 operation | movement can be suppressed low, and the fall of the luminous efficiency of LED31 can be suppressed.
　さらに、銅の熱伝導率は３９０Ｗ／ｍＫとアルミニウムの約１．７倍であり、銅製の基板を用いることで、放熱効率をさらに高めることが可能である。 Furthermore, the thermal conductivity of copper is 390 W / mK, which is about 1.7 times that of aluminum, and the heat dissipation efficiency can be further increased by using a copper substrate.
　なお、全体がアルミニウム、銅である必要はなく、樹脂製の機材の表面にアルミニウム、銅あるいはそれよりも熱伝導率の高い金属膜が形成されている基板であってもよい。その場合、表面と裏面との熱の伝導を容易にする構成となっていることが好ましい。 It should be noted that the whole need not be aluminum or copper, and may be a substrate on which aluminum, copper, or a metal film having a higher thermal conductivity is formed on the surface of resin equipment. In that case, it is preferable that the structure facilitates heat conduction between the front surface and the back surface.
　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他の例について図面を参照して説明する。図６はＬＥＤ基板の加工前の状態を示す正面図であり、図７は図６に示すＬＥＤ基板の断面図であり、図８は加工後のＬＥＤ基板の断面図である。 (Third embodiment)
Another example of the backlight according to the present invention will be described with reference to the drawings. 6 is a front view showing a state before processing the LED substrate, FIG. 7 is a sectional view of the LED substrate shown in FIG. 6, and FIG. 8 is a sectional view of the LED substrate after processing.
　ＬＥＤ基板５Ｂの製造について図面を参照して説明する。ＬＥＤ基板５Ｂは断面コの字型といった複雑な形状の基板であり、次の方法で製造を簡略化している。図６に示すように、加工前のＬＥＤ基板５０ｂは一枚の金属製基板であり、中央にＬＥＤ実装部５３ｂが、ＬＥＤ実装部５３の短手方向の両隣りに、第１対向部５１ｂ及び第２対向部５２ｂがそれぞれ配置されている。図７に示すように、ＬＥＤ実装部５３ｂと第１対向部５１ｂとの間の部分には断面三角形状（直角二等辺三角形）のノッチ５０１が形成されている。また、ＬＥＤ実装部５３ｂと第２対向部５２ｂの間の部分にはノッチ５０１と同形状のノッチ５０２が形成されている。 The manufacture of the LED substrate 5B will be described with reference to the drawings. The LED substrate 5B is a substrate having a complicated shape such as a U-shaped cross section, and the manufacturing is simplified by the following method. As shown in FIG. 6, the unprocessed LED substrate 50b is a single metal substrate, the LED mounting portion 53b at the center, the first facing portion 51b and the LED mounting portion 53 on both sides in the short direction. The second facing portions 52b are respectively disposed. As shown in FIG. 7, a notch 501 having a triangular cross section (right isosceles triangle) is formed in a portion between the LED mounting portion 53b and the first facing portion 51b. Further, a notch 502 having the same shape as the notch 501 is formed between the LED mounting portion 53b and the second facing portion 52b.
　図７に示すように、加工前のＬＥＤ基板５０の第１対向部５１ｂをノッチ５０１を中心に起こすとともに、第２対向部５２ｂをノッチ５０２を中心に起こすことで、図８に示すような断面コの字状のＬＥＤ基板５Ｂを形成することができる。 As shown in FIG. 7, the first opposing portion 51b of the LED substrate 50 before processing is raised with the notch 501 as the center, and the second opposing portion 52b is raised with the notch 502 as the center, so that the cross section as shown in FIG. A U-shaped LED substrate 5B can be formed.
　このような製造方法を採用することで、一枚の金属基板にノッチを形成する切削加工と、第１対向部５１ｂ、第２対向部５２ｂを起こす加工（プレス加工）とで、ＬＥＤ基板５Ｂを製造することができるので、加工が容易であり、製造に要する時間及び手間を減らすことが可能である。なお、製造されたＬＥＤ基板５Ｂは、第１対向部５１ｂ及び第２対向部５２ｂを、ノッチ５０１、５０２を中心に回動させることができるので、導光板２への取り付けが容易になる。また、製造完了後の形状は、第１の実施形態、第２の実施形態のＬＥＤ基板と同じであるので、効果については第１の実施形態及び第２の実施形態と同じである。 By adopting such a manufacturing method, the LED substrate 5B is formed by a cutting process for forming a notch in a single metal substrate and a process (press process) for raising the first facing part 51b and the second facing part 52b. Since it can be manufactured, processing is easy, and it is possible to reduce the time and labor required for manufacturing. In addition, since the manufactured LED board 5B can rotate the 1st opposing part 51b and the 2nd opposing part 52b centering on notch 501,502, the attachment to the light-guide plate 2 becomes easy. Moreover, since the shape after manufacture is the same as the LED board of 1st Embodiment and 2nd Embodiment, about the effect, it is the same as 1st Embodiment and 2nd Embodiment.
（第４の実施形態）
　本発明にかかるバックライトの他の例について説明する。ＬＥＤ基板５の第１対向部５１、第２対向部５２及びＬＥＤ実装部５３の内壁面には、ＬＥＤ基板５を保護するためのソルダレジストが形成されている。図２等に示しているように、ＬＥＤ基板５は受光面２２が形成されている端部を３方向から囲むように導光板２に取り付けられるものであり、少なくとも第１対向面５１及び第２対向面５２は導光板２の出光面２１及び裏面２３と接触して配置される。 (Fourth embodiment)
Another example of the backlight according to the present invention will be described. A solder resist for protecting the LED substrate 5 is formed on the inner wall surfaces of the first facing portion 51, the second facing portion 52, and the LED mounting portion 53 of the LED substrate 5. As shown in FIG. 2 and the like, the LED substrate 5 is attached to the light guide plate 2 so as to surround the end portion on which the light receiving surface 22 is formed from three directions, and at least the first facing surface 51 and the second surface. The facing surface 52 is disposed in contact with the light exit surface 21 and the back surface 23 of the light guide plate 2.
　ＬＥＤ３１から出射された光や導光板２の内部を伝播した光が、第１対向面５１又は第２対向面５２で反射される場合がある。また、受光面２２で反射されたり、導光板２を伝播した光が受光面２２より出光したりする場合もあり、その場合、光はＬＥＤ実装部５３のＬＥＤ３１が実装されている面に入射する。 The light emitted from the LED 31 or the light propagated through the light guide plate 2 may be reflected by the first facing surface 51 or the second facing surface 52. Moreover, the light reflected by the light receiving surface 22 or the light propagated through the light guide plate 2 may be emitted from the light receiving surface 22. In this case, the light is incident on the surface on which the LED 31 of the LED mounting portion 53 is mounted. .
　光が入射するＬＥＤ基板５の第１対向面５１、第２対向面５２及びＬＥＤ実装部５３の内壁面には、ソルダレジストが形成されており、ソルダレジストの色によっては、光が反射されずに吸収され、それだけ光の利用効率が低下する。そこで、ＬＥＤ基板５の内壁面には、光を効率よく反射する白色のソルダレジストを用いると、ＬＥＤ基板５で吸収される光を減らし、光の利用率を上げることができる。 A solder resist is formed on the first opposing surface 51, the second opposing surface 52 and the inner wall surface of the LED mounting portion 53 of the LED substrate 5 on which light is incident, and the light is not reflected depending on the color of the solder resist. As a result, the light use efficiency decreases. Therefore, when a white solder resist that efficiently reflects light is used on the inner wall surface of the LED substrate 5, the light absorbed by the LED substrate 5 can be reduced and the light utilization rate can be increased.
　例えば、反射率が７０％以上の高反射の白色のソルダレジストを用いることで、ＬＥＤ基板５に吸収される光の量が減る、すなわち、ＬＥＤ３１から出射された光の利用率が向上する。また、白色ソルダレジストとして、反射率が８０％以上の高反射白色ソルダレジスト、反射率が９０％以上の高反射白色ソルダレジストもあり、これらの高反射白色レジストを用いることで、吸収される光の割合を低下させることができ、光の利用効率をさらに向上することが可能である。このように、ＬＥＤ基板５の内壁面に反射率の高いソルダレジストを形成することで、光の利用効率を上げることができ、ＬＥＤ３１が発光するときに消費するエネルギ（電力）を低減することが可能である。 For example, by using a highly reflective white solder resist having a reflectance of 70% or more, the amount of light absorbed by the LED substrate 5 is reduced, that is, the utilization factor of light emitted from the LED 31 is improved. In addition, as a white solder resist, there are also a highly reflective white solder resist having a reflectance of 80% or more and a highly reflective white solder resist having a reflectance of 90% or more, and the light absorbed by using these highly reflective white resists. It is possible to reduce the ratio of light and to further improve the light use efficiency. As described above, by forming a solder resist having a high reflectance on the inner wall surface of the LED substrate 5, it is possible to increase the light use efficiency and reduce the energy (electric power) consumed when the LED 31 emits light. Is possible.
　なお、本実施形態では、ソルダレジスト自体を高反射の白色のものを利用する例を示しているが、白色のソルダレジストを用いる代わりに、通常のソルダレジストの上面に印刷等で白色の反射層を形成したものであってもよい。反射層を形成する場合でも高反射白色ソルダレジストを形成するものと同等の光利用効率を得ることが可能である。 In this embodiment, an example of using a highly reflective white solder resist is shown, but instead of using a white solder resist, a white reflective layer is printed on the upper surface of a normal solder resist. May be formed. Even when the reflective layer is formed, it is possible to obtain the same light utilization efficiency as that for forming the highly reflective white solder resist.
　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５の実施形態）
　本発明にかかるバックライトの他の例について図面を参照して説明する。図９は本発明にかかるバックライトのＬＥＤ基板部分を拡大した断面図である。図９に示すバックライト１はＬＥＤ基板５Ｃが異なる以外は、図２等に示すバックライト１と同じ構成を有するものであり、実質上同じ部分には同じ符号を付すとともに、同じ部分の詳細な説明は省略する。 (Fifth embodiment)
Another example of the backlight according to the present invention will be described with reference to the drawings. FIG. 9 is an enlarged cross-sectional view of the LED substrate portion of the backlight according to the present invention. The backlight 1 shown in FIG. 9 has the same configuration as that of the backlight 1 shown in FIG. 2 and the like except that the LED substrate 5C is different. Description is omitted.
　上述したように、導光板２の内部に入射した光は、反射を繰り返しながら導光板２の内部に伝播（拡散）する。このとき、導光板２よりも屈折率が低い（例えば、空気）と面している面に光が入射する場合、その入射角が導光板２の屈折率と空気の屈折率とで決まる臨界角よりも大きな角度で入射した光は、その境界面（導光板２の側面）で全反射され、全光量が導光板２の内部に伝播する。 As described above, the light incident on the inside of the light guide plate 2 propagates (diffuses) inside the light guide plate 2 while being repeatedly reflected. At this time, when light is incident on a surface facing a lower refractive index than the light guide plate 2 (for example, air), the incident angle is determined by the refractive index of the light guide plate 2 and the refractive index of air. Light incident at a larger angle is totally reflected at the boundary surface (side surface of the light guide plate 2), and the total amount of light propagates inside the light guide plate 2.
　一方で、導光板２の表面と光を透過しにくい部材（屈折率が導光板よりも高い部材）とが接触している場合、導光板２の内部の光が部材に入射すると、その角度にかかわらず光は部材に吸収される。ＬＥＤ基板は光を透過しにくい部材であるので、導光板２のＬＥＤ基板と接触する部分では、ＬＥＤ基板５Ｃが一定の反射率を有しているので反射率相当の反射光が発生するが、反射しなかった残りの光はＬＥＤ基板に吸収され、光の利用効率が低下する。 On the other hand, when the surface of the light guide plate 2 is in contact with a member that hardly transmits light (a member having a higher refractive index than the light guide plate), when light inside the light guide plate 2 enters the member, the angle is Regardless, light is absorbed by the member. Since the LED substrate is a member that does not easily transmit light, the LED substrate 5C has a constant reflectance at the portion of the light guide plate 2 that contacts the LED substrate, but reflected light corresponding to the reflectance is generated. The remaining light that has not been reflected is absorbed by the LED substrate, and the light use efficiency decreases.
　そこで、図９に示すバックライトに用いられているＬＥＤ基板５Ｃでは、第１対向部５１ｃの内壁面５１１、第２対向部５２ｃの内壁面５２１、すなわち、導光板２と対向する面の接触面積を減らすため、表面を粗面化している。 Therefore, in the LED substrate 5C used in the backlight shown in FIG. 9, the contact area of the inner wall surface 511 of the first facing portion 51c, the inner wall surface 521 of the second facing portion 52c, that is, the surface facing the light guide plate 2 is reached. In order to reduce this, the surface is roughened.
　図９に示しているように、第１対向部５１ｃの内壁面５１１、第２対向部５２ｃの内壁面５２１が粗面化されていることで、内壁面５１１と出光面２１、内壁面５２１と裏面２３との間に空気の層が形成される。これにより、導光板２内で伝播された光の第１対向部５１ｃ、第２対向部５２ｃに入射する入射角が、導光板２と空気のそれぞれの屈折率で決定される臨界角よりも大きい場合、導光板２で全反射される。これにより、ＬＥＤ基板５Ｃで吸収される光を減らすことが可能であり、光の利用効率を向上することが可能である。 As shown in FIG. 9, the inner wall surface 511 of the first facing portion 51c and the inner wall surface 521 of the second facing portion 52c are roughened, so that the inner wall surface 511, the light exit surface 21, the inner wall surface 521, An air layer is formed between the back surface 23. As a result, the incident angles of the light propagated in the light guide plate 2 and incident on the first facing portion 51c and the second facing portion 52c are larger than the critical angles determined by the respective refractive indexes of the light guide plate 2 and air. In this case, the light is totally reflected by the light guide plate 2. Thereby, the light absorbed by the LED substrate 5C can be reduced, and the light use efficiency can be improved.
　なお、第１対向部５１ｃ及び第２対向部５２ｃの内壁面は、導光板２の出光面２１及び裏面２３と対向（接触）する部分のみ粗面化されていることが好ましい。このように、対向（接触）部分のみ粗面化されていることで、ＬＥＤ３１から出射され受光面２２までの間に、第１対向部５１ｃ又は第２対向部５２ｃに到達した光は、それぞれの内壁面５１１、５２１で均一に反射される。 In addition, it is preferable that the inner wall surface of the 1st opposing part 51c and the 2nd opposing part 52c is roughened only the part facing the light emission surface 21 and the back surface 23 of the light-guide plate 2 (contact). Thus, only the facing (contact) portion is roughened, so that the light emitted from the LED 31 and reaching the light receiving surface 22 reaches the first facing portion 51c or the second facing portion 52c. Reflected uniformly by the inner wall surfaces 511 and 521.
（変形例）
　また、第１対向部５１ｃ及び第２対向部５２ｃは、導光板２との間に空気の層が形成されるように形成されていればよい。本実施形態の変形例について図面を参照して説明する。図１０ＡはＬＥＤ基板の他の例を示す断面図であり、図１０ＢはＬＥＤ基板の他の例を示す拡大した断面図である。図１０Ａに示すように、ＬＥＤ基板５Ｃの第１対向部５１ｃの内壁面５１１及び第２対向部５２ｃの内壁面５２１は、受光面２２の近傍のみ、出光面２１及び裏面２３と接触している。そして、内壁面５１１及び内壁面５２１の先端は導光板２の出光面２１、裏面２３から離れるように形成されている。 (Modification)
Moreover, the 1st opposing part 51c and the 2nd opposing part 52c should just be formed so that the layer of air may be formed between the light-guide plates 2. FIG. A modification of this embodiment will be described with reference to the drawings. FIG. 10A is a cross-sectional view showing another example of the LED substrate, and FIG. 10B is an enlarged cross-sectional view showing another example of the LED substrate. As shown in FIG. 10A, the inner wall surface 511 of the first facing portion 51c and the inner wall surface 521 of the second facing portion 52c of the LED substrate 5C are in contact with the light emitting surface 21 and the back surface 23 only in the vicinity of the light receiving surface 22. . And the front-end | tip of the inner wall surface 511 and the inner wall surface 521 is formed so that it may leave | separate from the light emission surface 21 and the back surface 23 of the light-guide plate 2. FIG.
　このように形成されることで、受光面２２とＬＥＤ基板５Ｃとが密着しており、受光面２２とＬＥＤ基板５Ｃとの隙間から光が漏れるのを抑制している。また、内壁面５１１と出光面２１、内壁面５２１と裏面２３との間に空気の層が形成されるので、導光板２の内部を伝播した光は、導光板２の内部で全反射することが可能であるので、光利用効率の低下を抑制することができる。 By being formed in this manner, the light receiving surface 22 and the LED substrate 5C are in close contact with each other, and light leakage from the gap between the light receiving surface 22 and the LED substrate 5C is suppressed. Further, since an air layer is formed between the inner wall surface 511 and the light exit surface 21, and between the inner wall surface 521 and the rear surface 23, the light propagated inside the light guide plate 2 is totally reflected inside the light guide plate 2. Therefore, a decrease in light utilization efficiency can be suppressed.
　また、図１０Ｂに示すように、受光面５１１及び受光面５２１に導光板２と接触する支柱部５１２、５２２が形成されていてもよい。なお、支柱部５１２は、導光板２と略点で接触する円柱状の支柱であり、支柱部５２２は導光板と略線で接触する板状の支柱である。このように、支柱部５１２、５２２を備えることで、ＬＥＤ基板５を安定的に導光板２に取り付けることが可能である。なお、支柱部５１２が板状の支柱で、支柱部５２２が円柱状の支柱であってもよく、両方が円柱状又は両方が柱状の支柱であってもよい。 Further, as shown in FIG. 10B, support columns 512 and 522 that contact the light guide plate 2 may be formed on the light receiving surface 511 and the light receiving surface 521. In addition, the support | pillar part 512 is a column-shaped support | pillar which contacts the light-guide plate 2 at a substantially point, and the support | pillar part 522 is a plate-shaped support | pillar which contacts a light-guide plate by a substantially line. As described above, the LED substrate 5 can be stably attached to the light guide plate 2 by providing the support columns 512 and 522. In addition, the support | pillar part 512 may be a plate-shaped support | pillar, the support | pillar part 522 may be a column-shaped support | pillar, both may be a column shape, or both may be a column-shaped support | pillar.
　支柱部５１２と出光面２１、支柱部５２２と裏面２３との接触面積はごく小さいので、導光板２の内部を伝播した光の全反射には影響しにくい。そのため、支柱部５１２、５２２を備えることで、ＬＥＤ基板５Ｃを安定して導光板２に取り付けることができるとともに、光の利用効率の低下を抑制することができる。なお、支柱部５１２、５２２の形状として、円柱状、板状のものを例に説明しているが、これに限定されるものではなく、導光板２の表面との接触面積が小さい支柱を広く採用することが可能である。 Since the contact area between the column part 512 and the light exit surface 21 and between the column part 522 and the back surface 23 is very small, it is difficult to affect the total reflection of the light propagated inside the light guide plate 2. Therefore, by providing the column portions 512 and 522, it is possible to stably attach the LED substrate 5C to the light guide plate 2, and it is possible to suppress a decrease in light utilization efficiency. In addition, although the column shape and the plate-like shape have been described as examples of the shape of the column portions 512 and 522, it is not limited to this, and a column with a small contact area with the surface of the light guide plate 2 is widely used. It is possible to adopt.
　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６の実施形態）
　本発明にかかるバックライトのさらに他の例について説明する。通常のバックライトでは、ＬＥＤ基板５とバックライトシャーシ１０との固定に両面粘着シートを用いている。通常、両面粘着シートは樹脂で形成されている場合がほとんどであり、熱伝導率が低く、ＬＥＤ基板５とバックライトシャーシ１０との間の熱抵抗になる場合が多い。 (Sixth embodiment)
Still another example of the backlight according to the present invention will be described. In a normal backlight, a double-sided pressure-sensitive adhesive sheet is used for fixing the LED substrate 5 and the backlight chassis 10. Usually, the double-sided pressure-sensitive adhesive sheet is mostly formed of a resin, has a low thermal conductivity, and often becomes a thermal resistance between the LED substrate 5 and the backlight chassis 10.
　つまり、ＬＥＤ３１で発生した熱が効率よくＬＥＤ基板５に伝導しても、ＬＥＤ基板５とバックライトシャーシ１０との間の両面粘着シートが熱抵抗となり、熱伝導があまり行われず、ＬＥＤ基板５の温度が上昇する。その結果、ＬＥＤ３１からＬＥＤ基板５へ伝導する熱が減少しＬＥＤ３１の温度が上昇し、ＬＥＤ３１の発光効率が低下する。また、ＬＥＤ基板５の温度が上昇することでＬＥＤ基板５と近接して配置されている導光板２にも熱が伝導し、導光板２が熱変形によって反ってしまうことがあり、光漏れの原因にもなる。 That is, even if the heat generated in the LED 31 is efficiently conducted to the LED substrate 5, the double-sided adhesive sheet between the LED substrate 5 and the backlight chassis 10 becomes a thermal resistance, and heat conduction is not performed so much. The temperature rises. As a result, the heat conducted from the LED 31 to the LED substrate 5 decreases, the temperature of the LED 31 increases, and the light emission efficiency of the LED 31 decreases. In addition, when the temperature of the LED substrate 5 rises, heat is also conducted to the light guide plate 2 disposed close to the LED substrate 5, and the light guide plate 2 may be warped due to thermal deformation. It can also be a cause.
　そこで、ＬＥＤ基板５とバックライトシャーシ１０とを熱伝導率の高い熱伝導性両面粘着シートを用いて固定することで、ＬＥＤ基板５からバックライトシャーシ１０への熱の伝導を高めることができ、ＬＥＤ基板５の熱を効率的に放熱することが可能となる。 Therefore, by fixing the LED substrate 5 and the backlight chassis 10 using a heat conductive double-sided adhesive sheet having a high thermal conductivity, heat conduction from the LED substrate 5 to the backlight chassis 10 can be increased. It becomes possible to efficiently radiate the heat of the LED substrate 5.
　例えば、従来よく用いられている両面粘着シートは、熱伝導率が０．１Ｗ／ｍＫであり、熱抵抗になっている。そこで、熱伝導率１．０Ｗ／ｍＫの熱伝導率の熱伝導性両面粘着シートを利用することで、放熱効率が上昇し、ＬＥＤ基板５の温度上昇を抑制することができる。これにより、ＬＥＤ３１の温度上昇も低減でき、ＬＥＤ３１の発光効率が低下するのを抑制することができる。また、導光板２の温度上昇も抑えることができるので、導光板２が反ることで発生する光漏れを抑制することが可能である。また、さらに熱伝導率の高い両面粘着シートを利用することで、さらに放熱効率を上げることが可能である。 For example, a double-sided pressure-sensitive adhesive sheet that has been often used conventionally has a thermal conductivity of 0.1 W / mK and a thermal resistance. Therefore, by using the heat conductive double-sided pressure-sensitive adhesive sheet having a heat conductivity of 1.0 W / mK, the heat dissipation efficiency is increased, and the temperature rise of the LED substrate 5 can be suppressed. Thereby, the temperature rise of LED31 can also be reduced and it can suppress that the luminous efficiency of LED31 falls. Moreover, since the temperature rise of the light-guide plate 2 can also be suppressed, it is possible to suppress light leakage that occurs when the light-guide plate 2 is warped. Further, by using a double-sided pressure-sensitive adhesive sheet having higher thermal conductivity, it is possible to further increase the heat radiation efficiency.
　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.
　以上示した各実施形態において、ＬＥＤ基板は、第１対向部の短手方向の長さ（幅）と第２対向部の短手方向の長さ（幅）とが同じものとしているが、異なるものであってもよいのはもちろんである。例えば、ＬＥＤ３１から出射される光のうち、反射シート１０３側に伝播する光は、出光面２１より直接出射するものではないので、ある程度は反射シート１０３と導光板２との間に照射されてもよい。そのため、第２対向部の幅が第１対向部の幅よりも短めに形成されているものであってもよい。 In each of the embodiments described above, the LED substrate has the same length (width) in the short direction of the first facing portion and the length (width) in the short direction of the second facing portion, but is different. Of course, it may be a thing. For example, of the light emitted from the LED 31, the light propagating to the reflective sheet 103 side is not directly emitted from the light exit surface 21, so that even if it is irradiated to some extent between the reflective sheet 103 and the light guide plate 2. Good. Therefore, the width of the second facing portion may be shorter than the width of the first facing portion.
　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　反射シート
２　導光板
３　光源ユニット
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　ＬＥＤ基板
５１　第１対向部
５２　第２対向部
５３　ＬＥＤ実装部
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 Reflective sheet 2 Light guide plate 3 Light source unit 31 LED
4 Optical sheet 41 Diffusion sheet 42 Brightness improving sheet 43 Prism sheet 5 LED substrate 51 First facing portion 52 Second facing portion 53 LED mounting portion 6 Liquid crystal panel unit 61 Liquid crystal panel 62 Polarizing plate 7 Bezel 8 Driving substrate

Claims (10)

  1. 　側面の受光面から光が入射され、一主面の出光面より面状光を出射する導光板と、
    　複数個のＬＥＤが列状に実装されたＬＥＤ実装部、前記ＬＥＤ実装部より突出し前記ＬＥＤを囲むように配置された第１対向部及び第２対向部を含む断面コの字状のＬＥＤ基板と、を有し、
    　前記ＬＥＤ基板は、前記ＬＥＤ実装部が前記受光面と対向するとともに、前記第１対向部が前記出光面と、前記第２対向部が前記出光面の裏側の面と接触するように導光板に取り付けられていることを特徴とするバックライト。     A light guide plate that receives light from the light receiving surface on the side surface and emits planar light from the light exit surface of one main surface;
    An LED mounting portion in which a plurality of LEDs are mounted in a row, an LED substrate having a U-shaped cross section including a first opposing portion and a second opposing portion that are arranged so as to protrude from the LED mounting portion and surround the LED; Have
    The LED substrate is disposed on the light guide plate such that the LED mounting portion faces the light receiving surface, the first facing portion contacts the light exit surface, and the second facing portion contacts the back surface of the light exit surface. Backlight characterized by being attached.
  2. 　前記ＬＥＤ基板は、金属材料で形成されている請求項１に記載のバックライト。 The backlight according to claim 1, wherein the LED substrate is formed of a metal material.
  3. 　前記ＬＥＤ基板は、ノッチが形成された平板状の金属基板を折り曲げて作製される請求項２に記載のバックライト。 The backlight according to claim 2, wherein the LED substrate is manufactured by bending a flat metal substrate having a notch.
  4. 　前記ＬＥＤ実装部、前記第１対向部及び前記第２対向部の前記導光板と対向する面には、白色レジストが施されている請求項１から請求項３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 3, wherein a white resist is applied to a surface of the LED mounting portion, the first facing portion, and the second facing portion that faces the light guide plate.
  5. 　前記第１対向部及び前記第２対向部の少なくとも前記導光板と接触する面が、粗面化されている請求項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 at least surfaces of the first facing portion and the second facing portion that are in contact with the light guide plate are roughened.
  6. 　前記第１対向部又は前記第２対向部の少なくとも一方の前記導光板と対向する面は、端部側が前記導光板との間に隙間が開くように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。 5. The surface of the first facing portion or the second facing portion that faces at least one of the light guide plates is formed such that a gap is opened between the end portion side and the light guide plate. The backlight in any one of.
  7. 　前記第１対向部又は前記第２対向部の少なくとも一方の前記導光板と対向する面の前記導光板との間に隙間が形成されている部分には、前記第１対向部又は前記第２対向部と前記導光板との隙間を維持するための支柱部が形成されている請求項６に記載のバックライト。 At a portion where a gap is formed between the light guide plate on the surface facing at least one of the light guide plate of the first counter portion or the second counter portion, the first counter portion or the second counter portion is formed. The backlight according to claim 6, wherein a support column part is formed to maintain a gap between the part and the light guide plate.
  8. 　前記支柱部は前記導光板と点接触する円柱状である請求項７に記載のバックライト。 The backlight according to claim 7, wherein the support column has a cylindrical shape that makes point contact with the light guide plate.
  9. 　前記支柱部は前記導光板と線接触する板状である請求項７に記載のバックライト。 The backlight according to claim 7, wherein the support column has a plate shape in line contact with the light guide plate.
  10. 　請求項１から請求項９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 9,
    And a liquid crystal panel unit disposed on the front side of the backlight.
PCT/JP2012/067216 2011-08-01 2012-07-05 Backlight and liquid crystal display device WO2013018499A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2011168519 2011-08-01
JP2011-168519 2011-08-01

Publications (1)

Publication Number Publication Date
WO2013018499A1 true WO2013018499A1 (en) 2013-02-07

Family

ID=47629030

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2012/067216 WO2013018499A1 (en) 2011-08-01 2012-07-05 Backlight and liquid crystal display device

Country Status (1)

Country Link
WO (1) WO2013018499A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016189413A (en) * 2015-03-30 2016-11-04 大日本印刷株式会社 Led packaging module and led display device
US11931490B2 (en) 2018-10-05 2024-03-19 Seoul Viosys Co., Ltd. Air purification module and refrigerator comprising the same

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006310221A (en) * 2005-05-02 2006-11-09 Matsushita Electric Ind Co Ltd Edge input type backlight and liquid crystal display device
JP2009158315A (en) * 2007-12-27 2009-07-16 Hitachi Ltd Light source module
JP2009252419A (en) * 2008-04-03 2009-10-29 Minebea Co Ltd Linear light source device and planar lighting device
JP2010092739A (en) * 2008-10-08 2010-04-22 Sumitomo Electric Printed Circuit Inc Wiring module, method of manufacturing the same, and electronic equipment
JP2010146931A (en) * 2008-12-22 2010-07-01 Minebea Co Ltd Linear and planar light-source devices
JP2010147012A (en) * 2008-12-22 2010-07-01 Panasonic Electric Works Co Ltd Planar light source, and display lighting fixture
JP2010198792A (en) * 2009-02-23 2010-09-09 More Tenso:Kk Shelf with lighting system

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006310221A (en) * 2005-05-02 2006-11-09 Matsushita Electric Ind Co Ltd Edge input type backlight and liquid crystal display device
JP2009158315A (en) * 2007-12-27 2009-07-16 Hitachi Ltd Light source module
JP2009252419A (en) * 2008-04-03 2009-10-29 Minebea Co Ltd Linear light source device and planar lighting device
JP2010092739A (en) * 2008-10-08 2010-04-22 Sumitomo Electric Printed Circuit Inc Wiring module, method of manufacturing the same, and electronic equipment
JP2010146931A (en) * 2008-12-22 2010-07-01 Minebea Co Ltd Linear and planar light-source devices
JP2010147012A (en) * 2008-12-22 2010-07-01 Panasonic Electric Works Co Ltd Planar light source, and display lighting fixture
JP2010198792A (en) * 2009-02-23 2010-09-09 More Tenso:Kk Shelf with lighting system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016189413A (en) * 2015-03-30 2016-11-04 大日本印刷株式会社 Led packaging module and led display device
US11931490B2 (en) 2018-10-05 2024-03-19 Seoul Viosys Co., Ltd. Air purification module and refrigerator comprising the same

Similar Documents

Publication Publication Date Title
JP4640188B2 (en) Surface light source device
KR101529556B1 (en) Liquid crystal display device having good heat radiating function
US7440046B2 (en) Backlight assembly and liquid crystal display having the same
JP4840121B2 (en) Surface light source device
JP5064528B2 (en) Backlight unit and liquid crystal display device including the same
US20110128463A1 (en) Liquid crystal display device
JP2010177190A (en) Backlight assembly
JP2006156324A (en) Backlight unit and liquid crystal display device provided with the same
JP2006310221A (en) Edge input type backlight and liquid crystal display device
JP2007286467A (en) Back-light device and liquid crystal display device
KR20130048607A (en) Backlight unit, display apparatus using the same, and the lighting apparatus including the same
WO2014021304A1 (en) Illumination device, display device, and television reception device
WO2012169441A1 (en) Lighting device, display device and television receiver
KR20160117026A (en) Display device
KR101513160B1 (en) Liquid crystal display device having heat radiation sheet
KR101796553B1 (en) Liquid crystal display device
TWI410717B (en) Liquid crystal display device
WO2012102193A1 (en) Lighting device, display device, and television reception device
WO2011052259A1 (en) Lighting device, and display device
JP5098778B2 (en) LIGHTING DEVICE, LIQUID CRYSTAL DISPLAY DEVICE, AND ELECTRONIC DEVICE
WO2013018499A1 (en) Backlight and liquid crystal display device
KR20120136879A (en) Liquid crystal display device
KR102047223B1 (en) Backlight unit using LED and liquid crystal display device including the same
KR20120018979A (en) Liquid crystal display device
KR20130001522A (en) Cover bottom and liquid crystal display device module including the same

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: 12819316

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: 12819316

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: JP