WO2021111749A1 - Planar illumination device - Google Patents

Planar illumination device Download PDF

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Publication number
WO2021111749A1
WO2021111749A1 PCT/JP2020/039411 JP2020039411W WO2021111749A1 WO 2021111749 A1 WO2021111749 A1 WO 2021111749A1 JP 2020039411 W JP2020039411 W JP 2020039411W WO 2021111749 A1 WO2021111749 A1 WO 2021111749A1
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WO
WIPO (PCT)
Prior art keywords
light
guide plate
light guide
lighting device
planar lighting
Prior art date
Application number
PCT/JP2020/039411
Other languages
French (fr)
Japanese (ja)
Inventor
和正 安達
暢彦 吉垣
Original Assignee
ミネベアミツミ株式会社
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 ミネベアミツミ株式会社 filed Critical ミネベアミツミ株式会社
Priority to CN202080071294.0A priority Critical patent/CN114556170A/en
Publication of WO2021111749A1 publication Critical patent/WO2021111749A1/en

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    • 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
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0055—Reflecting element, sheet or layer
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S2/00—Systems of lighting devices, not provided for in main groups F21S4/00 - F21S10/00 or F21S19/00, e.g. of modular construction
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]

Definitions

  • the present invention relates to a planar lighting device.
  • a so-called edge light type planar illumination device is known in which light is incident from the light entering side surface of the light guide plate and is emitted from one main surface of the light guide plate (see, for example, Patent Documents 1 and 2). ).
  • Such a planar lighting device is used as a backlight or the like in an in-vehicle liquid crystal display device.
  • a top frame provided with an opening for light emission is often used as a part of a housing, and the part of the top frame forming the opening for light emission is called a frame. ing.
  • a frame the part of the top frame forming the opening for light emission.
  • various optical sheets such as a diffusion sheet, a prism sheet, and a brightness improving sheet are laminated on the exit surface side of the light guide plate in order to adjust brightness uniformity and light distribution characteristics.
  • the amount of coverage between the light guide plate and the frame decreases, and when the user looks into the exit surface from the diagonally front direction, the light leaking from the light guide plate becomes linear. It looks like a picture frame and may feel strange.
  • the light leaked from the side surface other than the light entering side surface of the light guide plate is reflected on the inner surface of the side wall through the gap between the side surface and the inner surface of the side wall of the bottom frame, penetrates the optical sheet, and then passes through the Z clearance. It may be reflected and come out.
  • the frame of the planar lighting device becomes narrower, it is considered that measures against such edge light will become important.
  • the present invention has been made in view of the above, and an object of the present invention is to provide a planar lighting device capable of effectively suppressing end light.
  • the planar illumination device includes a light guide plate, a plurality of light sources, one or more optical sheets, and a bottom frame and a top frame. Be prepared.
  • the light guide plate receives light from the side of the light entering.
  • the plurality of light sources irradiate the light incoming side surface of the light guide plate with light.
  • the one or more optical sheets are laminated on the exit surface side of the light guide plate.
  • the bottom frame and the top frame accommodate the light guide plate, the light source, and the optical sheet.
  • a gap is provided between the light guide plate and any side surface of the optical sheet on the non-light receiving side with the inner surface of the side wall of the bottom frame.
  • the light guide plate and the end of the optical sheet are sandwiched between the eaves forming the opening of the top frame and the floor of the bottom frame.
  • a reflective layer is formed on any side surface of the light guide plate on the non-light receiving side where the gap is provided.
  • planar lighting device can effectively suppress end light.
  • FIG. 1 is an external perspective view of the planar lighting device according to the embodiment.
  • FIG. 2 is a YY end view of the planar lighting device in FIG.
  • FIG. 3A is an end view showing a configuration example of the planar lighting device according to the comparative example.
  • FIG. 3B is a diagram showing a state in which the exit surface of the planar lighting device is viewed from the front and a state in which the emission surface of the planar lighting device is viewed from a 45 ° oblique front direction.
  • FIG. 4A is an end view showing a state in which a light-shielding portion is added to the planar lighting device of the comparative example.
  • FIG. 1 is an external perspective view of the planar lighting device according to the embodiment.
  • FIG. 2 is a YY end view of the planar lighting device in FIG.
  • FIG. 3A is an end view showing a configuration example of the planar lighting device according to the comparative example.
  • FIG. 3B is a diagram showing a
  • FIG. 4B is a diagram showing a state in which the exit surface of the planar lighting device is viewed from the front and a state in which the emission surface of the planar lighting device is viewed from a 45 ° oblique front direction.
  • FIG. 5 is a diagram showing an example of the relationship between the position crossing the vicinity of the end portion and the brightness when the exit surface of the planar lighting device is viewed from the front in a state without a light-shielding portion and a state with a light-shielding portion.
  • FIG. 6 is a diagram showing an example of the relationship between the brightness and the position crossing the vicinity of the end portion when the exit surface of the planar lighting device is viewed from the front direction at an angle of 45 ° in the state without the light-shielding portion and in the state with the light-shielding portion. is there.
  • FIG. 7A is a diagram showing a state in which the exit surface is viewed from a 45 ° obliquely front direction in the case where the reflective layer is not provided and the case where the reflective layer made of various materials is provided in the planar lighting device.
  • FIG. 7B is a diagram showing an example of the relationship between the position crossing the vicinity of the end portion (broken line portion in FIG.
  • FIG. 8A is a diagram showing a state in which the exit surface is viewed from the front when the reflective layer is not provided and when the reflective layer is provided with various materials in the planar lighting device.
  • FIG. 8B is a diagram showing an example of the relationship between the position crossing the vicinity of the end portion (broken line portion in FIG. 8A) and the brightness when the exit surface is viewed from the front.
  • planar lighting device according to the embodiment will be described with reference to the drawings.
  • the present invention is not limited to this embodiment.
  • the relationship between the dimensions of each element in the drawing, the ratio of each element, and the like may differ from the reality. Even between drawings, there may be parts with different dimensional relationships and ratios. Further, in principle, the contents described in one embodiment or modification are similarly applied to other embodiments or modifications.
  • FIG. 1 is an external perspective view of the planar lighting device 1 according to the embodiment.
  • the left-right direction of the figure is the X-axis direction
  • the depth direction of the figure is the Y-axis direction
  • the vertical direction of the figure is the Z-axis direction.
  • the planar lighting device 1 has a substantially rectangular shape (may be a substantially square shape) and has a substantially plate-like outer shape, and has a floor box-shaped bottom frame 2 for accommodating a light guide plate and the like, which will be described later, and a bottom frame.
  • the housing is composed of a top frame 3 that covers the opening side of 2.
  • the top frame 3 is provided with an exit surface 4 by a substantially rectangular opening 3a, so that light is emitted from the inside to the outside of the surface illumination device 1.
  • the bottom frame 2 and the top frame 3 are formed of die casting, sheet metal, or the like.
  • FIG. 2 is a YY end view of the planar lighting device 1 in FIG.
  • the bottom frame 2 has a floor portion 2a and a side wall 2b surrounding four sides around the floor portion 2a.
  • a reflective sheet 5, a light guide plate 6, and optical sheets 7, 8 and 9 are laminated in this order on the floor portion 2a of the bottom frame 2.
  • the reflective sheet 5 is for reflecting the light leaked from the light guide plate 6 to the floor portion 2a side and returning it to the light guide plate 6. If the inner surface of the floor portion 2a of the bottom frame 2 is painted white and has good reflection characteristics, the reflection sheet 5 may be omitted.
  • the light guide plate 6 is made of a transparent resin such as acrylic, and guides the light incident from one side surface (light entry side surface) to the entire surface and emits it from one main surface.
  • Reflective layers 6a are provided on all or any of the three sides of the light guide plate 6 on the non-light receiving side.
  • the reflective layer 6a is for preventing light from the inside of the light guide plate 6 from leaking to the outside of the light guide plate 6. Since it is difficult to return the light once leaked from the light guide plate 6 to the light guide plate 6, the reflective layer 6a prevents the light from leaking from the light guide plate 6 as much as possible.
  • the brightness of the light emitting surface 4 is likely to decrease due to the absorption and scattering of light by the reflective layer 6a, so that the light is not simply leaked. It is important not only to do so, but also to reflect almost all the light that has reached the reflective layer 6a.
  • the specific effect of the reflective layer 6a will be described later, but one due to total reflection and one due to diffuse reflection can be used.
  • the total internal reflection can be realized by adhering a sheet (tape) on which a metal such as silver or aluminum is vapor-deposited, or by depositing a metal such as silver or aluminum directly on the side surface of the light guide plate 6. it can.
  • a sheet (tape) it is desirable to use, for example, an acrylic adhesive having less light scattering or absorption in order to prevent light scattering or absorption by the adhesive (adhesive layer).
  • the adhesive is directly sprayed on the sheet (tape). Or may be applied.
  • the position of the side surface of the light guide plate 6 can be separated from the opening 3a of the top frame 3 by the thickness of the base material.
  • the diffuse reflection can be realized by adhering a sheet (tape) or the like of a white PET (polyethylene terephthalate) material.
  • the optical sheet 7 is, for example, a diffusion sheet.
  • the optical sheet 8 is, for example, a prism sheet.
  • the optical sheet 9 is, for example, a brightness increasing film (DBEF: Dual Brightness Enhancement Film).
  • DBEF Dual Brightness Enhancement Film
  • a substrate 10 in which a plurality of light sources 11 by LEDs (Light Emitting Diodes) are arranged in a row is fixed to the side wall 2b of the bottom frame 2, and the light source 11 emits light.
  • the surface faces the side surface (light entry side surface) of the light guide plate 6.
  • a top view type LED or the like that emits light from the top surface
  • the surface of the substrate 10 is arranged orthogonal to the light entering side surface of the light guide plate 6.
  • FIG. 3A is an end view showing a configuration example of the planar illumination device 1'according to the comparative example, and shows an end portion on the non-light receiving side.
  • the reflective sheet 5', the light guide plate 6', and the optical sheets 7', 8', and 9' are arranged in this order on the floor portion 2a'of the bottom frame 2'.
  • a gap is formed between the non-light receiving side end of the light guide plate 6'and the inner surface of the side wall 2b' of the bottom frame 2', and the end of the light guide plate 6'and the like is the eaves of the top frame 3'.
  • a reflecting portion 12'by a white PET material sheet (tape) or the like is provided on the inner surface of the side wall 2b'of the bottom frame 2'.
  • the reflective sheet 5'and the reflective portion 12' may be integrated by extending and bending the reflective sheet 5'to the side wall 2b'.
  • the configuration on the incoming light side is the same as in FIG.
  • the arrival path of the end light observed when the user looks into the exit surface from the diagonally front direction is considered to be due to the broken lines A, B, and C.
  • the broken line A indicates that the light leaking from the side surface of the light guide plate 6'is incident on the reflecting portion 12'through the gap between the side wall 2b'of the bottom frame 2'and the light guide plate 6'and is reflected, and is reflected by the optical sheet 9'. It is reflected in the clearance (Z clearance) between the top frame 3'and the eaves 3b' of the top frame 3'.
  • the broken line B the light leaking from the side surface of the light guide plate 6'is incident on the reflecting portion 12'through the gap between the side wall 2b'of the bottom frame 2'and the optical sheet 7'. , 8', 9', and then reflected in the Z clearance.
  • the broken line C indicates that the brilliance of the corner portion of the light guide plate 6'on the reflective sheet 5'side comes out through the light guide plate 6', the optical sheets 7', 8', and 9'.
  • FIG. 3B is a diagram showing a state in which the exit surface of the planar lighting device 1'in FIG. 3A is viewed from the front (upper row) and a state in which the exit surface is viewed from a 45 ° oblique front direction (lower row).
  • FIG. 4A is an end view showing a state in which a light-shielding portion 13'is added to the planar illumination device 1'of the comparative example, and includes an end portion of the light guide plate 6'on the non-light receiving side and an end portion of the optical sheet 7'.
  • a light-shielding portion 13'made of a white PET material or the like is sandwiched between the light-shielding portions 13', and the light-shielding portion 13'extends until it comes into contact with the reflective portion 12'. As a result, the paths of the broken lines A and B in FIG. 3A are blocked.
  • the light-shielding portion 13' is provided with a width W in the depth direction from the front end in FIG. 4A.
  • FIG. 4B is a diagram showing a state in which the exit surface of the planar lighting device 1'in FIG. 4A is viewed from the front (upper row) and a state in which the exit surface of the planar illumination device 1'in FIG. 4A is viewed from a 45 ° diagonally front direction (lower row). It is not clear when viewed from the front of the upper row, but when viewed from the 45 ° diagonally front direction of the lower row, the linear end light in the vicinity of the end E disappears in the region of the width W where the light-shielding portion 13'is provided. doing.
  • FIG. 5 is a diagram showing an example of the relationship between the brightness and the position crossing the vicinity of the end portion when the exit surface of the planar lighting device 1'is viewed from the front in the state without the light-shielding portion 13'and in the state with the light-shielding portion 13'. is there.
  • FIG. 6 shows an example of the relationship between the position crossing the vicinity of the end portion and the brightness when the exit surface of the planar lighting device 1'is viewed from the front direction at an angle of 45 ° in the state without the light-shielding portion 13'and in the state with the light-shielding portion 13'. It is a figure which shows.
  • the position crossing the vicinity of the end portion is a position on a line indicated by a chain line in the vertical direction in FIGS. 3B and 4B, and the origin is placed on the frame outside the exit surface.
  • the light-shielding portion 13'in FIG. 4A can suppress the generation of end light, but it is difficult to provide the light-shielding portion 13'. That is, since the light guide plate 6'and the optical sheets 7', 8', and 9'expand and contract due to temperature changes, the light-shielding portion 13'is stabilized between their ends and the side wall 2b'of the bottom frame 2'. This is because it is difficult to arrange. Therefore, in the planar illumination device 1 of FIG. 2, a reflection layer 6a is provided integrally with the light guide plate 6 on all or any of the three sides of the light guide plate 6 on the non-light receiving side.
  • FIG. 7A is a diagram showing a state in which the exit surface is viewed from a 45 ° obliquely front direction in the case where the reflective layer 6a is not provided and the case where the reflective layer 6a made of various materials is provided in the planar lighting device 1. ..
  • "INITIAL” is a case where the reflective layer 6a is not provided (instead, when a reflective portion 12'is provided as shown in FIG. 3A), "white PET” is a white PET material as the reflective layer 6a. Is affixed with double-sided tape, the "Al vapor-deposited tape" is used as the reflective layer 6a.
  • the "Ag reflective tape” is silver as the reflective layer 6a. This is the case where the tape on which is vapor-deposited is attached with double-sided tape. In the case of "white PET”, it is diffuse reflection, and in the case of "Al vapor deposition tape” and “Ag reflection tape”, it is specular reflection. The reflectance of the "Al-deposited tape” is about 90%, and the reflectance of the "Ag reflective tape” is about 97%.
  • FIG. 7B is a diagram showing an example of the relationship between the position crossing the vicinity of the end portion (broken line portion in FIG. 7A) and the brightness when the exit surface is viewed from the front direction at an angle of 45 °.
  • the brightness increased in P2 in "INITIAL" without the reflective layer 6a does not increase in any material when the reflective layer 6a is provided, and the edge light is suppressed.
  • any material of "white PET", “Al vapor deposition tape", and “Ag reflective tape” may be used for the reflective layer 6a from the viewpoint of suppressing edge light.
  • “Al-deposited tape” and “Ag-reflecting tape” that provide specular reflection are preferable.
  • FIG. 8A is a diagram showing a state in which the exit surface is viewed from the front when the reflective layer 6a is not provided and when the reflective layer 6a made of various materials is provided in the planar lighting device 1.
  • FIG. 8B is a diagram showing an example of the relationship between the position crossing the vicinity of the end portion (broken line portion in FIG. 8A) and the brightness when the exit surface is viewed from the front.
  • FIG. 8B in the case of "Al-deposited tape" in P3, a decrease in brightness of 2 to 3% is observed. It is considered that this is because the reflectance of the "Al-deposited tape" is about 90%. Therefore, considering the result of FIG. 7B and the result of FIG. 8B, it is considered that the "Ag reflective tape" having a specular reflection is the most preferable.
  • the planar illumination device is laminated with a light guide plate that receives light from the light entrance side surface, a plurality of light sources that irradiate the light entrance side surface of the light guide plate, and a light guide plate on the exit surface side.
  • One or more optical sheets, and a bottom frame and a top frame accommodating a light guide plate, a light source, and an optical sheet are provided, and a side wall of the bottom frame is provided on any side surface of the light guide plate and the optical sheet on the non-light receiving side.
  • a gap is provided between the inner surface and the edge of the light guide plate and the optical sheet between the eaves forming the opening of the top frame and the floor of the bottom frame.
  • a reflective layer is formed on any side surface provided with a gap. Thereby, the end light can be effectively suppressed.
  • the reflective layer is a specular reflective layer. As a result, the edge light can be suppressed more effectively than the diffuse reflection.
  • the specular reflection layer includes a layer made by vapor deposition of silver. As a result, the end light can be suppressed more effectively than other materials.
  • the specular reflection layer includes a layer made by vapor deposition of aluminum. As a result, edge light can be effectively suppressed, although it is slightly inferior to the case where a layer formed by vapor deposition of silver is included.
  • the reflective layer is a diffuse reflective layer.
  • the edge light can be effectively suppressed, although it is slightly inferior to the case of specular reflection.
  • the diffuse reflection layer includes a layer made of white PET material. As a result, the edge light can be effectively suppressed, although it is slightly inferior to the case of specular reflection.
  • a clearance is provided between the edge of the light guide plate and the optical sheet sandwiched between the eaves and the floor and the eaves. Thereby, expansion and contraction of the light guide plate and the optical sheet can be allowed.
  • the present invention is not limited by the above-described embodiment.
  • the present invention also includes a configuration in which the above-mentioned components are appropriately combined. Further, further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspect of the present invention is not limited to the above-described embodiment, and various modifications can be made.
  • 1 planar lighting device 2 bottom frame, 3 top frame, 3a opening, 3b eaves, 4 exit surface, 5 reflective sheet, 6 light guide plate, 6a reflective layer, 7-9 optical sheet, 10 substrate, 11 light source

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
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  • Planar Illumination Modules (AREA)

Abstract

A planar illumination device (1) according to one embodiment comprises: a light guide plate (6); a plurality of light sources (11); one or more optical sheets (7-9); and a bottom frame (2) and a top frame (3). The light guide plate (6) receives light from a light-incident-side surface. The plurality of light sources (11) irradiate the light-incident-side surface of the light guide plate (6) with light. The one or more optical sheets (7-9) are laminated on an emission-side surface of the light guide plate (6). The bottom frame (2) and the top frame (3) accommodate the light guide plate (6), the light sources (11), and the optical sheets (7-9). One side surface on the non-light-incident side of the light guide plate (6) and the optical sheets (7-9) is provided with a gap between the side surface and the inner surface of a side wall (2b) of the bottom frame (2). The ends of the light guide plate (6) and the optical sheets (7-9) are held between an eaves part (3b) forming an opening (3a) in the top frame (3) and a floor part (2a) of the bottom frame (2). A reflective layer (6a) is formed on the one side surface of the non-light-incident-side of the light guide plate (6) provided with the gap.

Description

面状照明装置Planar lighting device
　本発明は、面状照明装置に関する。 The present invention relates to a planar lighting device.
　導光板の入光側面から光を入射し、導光板の一方の主面から光を出射する、いわゆるエッジライト型の面状照明装置が知られている（例えば、特許文献１、２等を参照）。このような面状照明装置は、車載用の液晶表示装置におけるバックライト等として用いられている。 A so-called edge light type planar illumination device is known in which light is incident from the light entering side surface of the light guide plate and is emitted from one main surface of the light guide plate (see, for example, Patent Documents 1 and 2). ). Such a planar lighting device is used as a backlight or the like in an in-vehicle liquid crystal display device.
　一般的な面状照明装置では、光出射用の開口が設けられたトップフレームが筐体の一部として用いられることが多く、トップフレームにおける光出射用の開口を形成する部分は額縁と呼ばれている。昨今では主にデザイン上の観点から、額縁の幅を狭くする狭額縁化が要請されている。 In a general planar lighting device, a top frame provided with an opening for light emission is often used as a part of a housing, and the part of the top frame forming the opening for light emission is called a frame. ing. Nowadays, there is a demand for narrowing the width of the frame, mainly from the viewpoint of design.
　また、一般的な面状照明装置では、輝度均一性や配光特性を調整するために、拡散シート、プリズムシート、輝度向上シート等の各種の光学シートが導光板の出射面側に積層されている。 Further, in a general planar lighting device, various optical sheets such as a diffusion sheet, a prism sheet, and a brightness improving sheet are laminated on the exit surface side of the light guide plate in order to adjust brightness uniformity and light distribution characteristics. There is.
特開２００５－７７７５３号公報Japanese Unexamined Patent Publication No. 2005-77753 特開２０１７－９８２７１号公報JP-A-2017-98271
　しかしながら、面状照明装置の狭額縁化に伴い、導光板と額縁との被り量が減少し、ユーザが出射面を斜め手前方向から覗き込んだときに、導光板からの漏れ光が直線状の端光として見え、違和感がある場合がある。端光の要因としては、いくつかが考えられる。一つは、導光板の入光側面以外の側面から漏れ出た光が、ボトムフレームの側壁の内面との間の隙間を介して側壁の内面にて反射し、光学シートとトップフレームの庇部（額縁を構成する部分）との間のクリアランス（Ｚクリアランス）内を反射して出てくる場合が考えられる。また、導光板の入光側面以外の側面から漏れ出た光が、ボトムフレームの側壁の内面との間の隙間を介して側壁の内面にて反射し、光学シートを貫通した後にＺクリアランス内を反射して出てくる場合が考えられる。今後、面状照明装置の狭額縁化が進むにつれ、そのような端光への対策が重要になってくると考えられる。 However, with the narrowing of the frame of the planar lighting device, the amount of coverage between the light guide plate and the frame decreases, and when the user looks into the exit surface from the diagonally front direction, the light leaking from the light guide plate becomes linear. It looks like a picture frame and may feel strange. There are several possible causes of the end light. One is that the light leaked from the side surface other than the light entry side surface of the light guide plate is reflected on the inner surface of the side wall through the gap between the inner surface of the side wall of the bottom frame and the eaves of the optical sheet and the top frame. It is conceivable that the light may be reflected in the clearance (Z clearance) between the frame and the frame. Further, the light leaked from the side surface other than the light entering side surface of the light guide plate is reflected on the inner surface of the side wall through the gap between the side surface and the inner surface of the side wall of the bottom frame, penetrates the optical sheet, and then passes through the Z clearance. It may be reflected and come out. In the future, as the frame of the planar lighting device becomes narrower, it is considered that measures against such edge light will become important.
　本発明は、上記に鑑みてなされたものであって、端光を有効に抑制することのできる面状照明装置を提供することを目的とする。 The present invention has been made in view of the above, and an object of the present invention is to provide a planar lighting device capable of effectively suppressing end light.
　上述した課題を解決し、目的を達成するために、本発明の一態様に係る面状照明装置は、導光板と、複数の光源と、１以上の光学シートと、ボトムフレームおよびトップフレームとを備える。前記導光板は、入光側面から入光する。前記複数の光源は、前記導光板の入光側面に光を照射する。前記１以上の光学シートは、前記導光板の出射面側に積層される。前記ボトムフレームおよび前記トップフレームは、前記導光板、前記光源および前記光学シートを収容する。前記導光板および前記光学シートの非入光側のいずれかの側面には前記ボトムフレームの側壁の内面との間に隙間が設けられる。前記トップフレームの開口部を形成する庇部と前記ボトムフレームの床部との間に前記導光板および前記光学シートの端部が挟持される。前記導光板の非入光側の前記隙間が設けられたいずれかの側面には、反射層が形成されている。 In order to solve the above-mentioned problems and achieve the object, the planar illumination device according to one aspect of the present invention includes a light guide plate, a plurality of light sources, one or more optical sheets, and a bottom frame and a top frame. Be prepared. The light guide plate receives light from the side of the light entering. The plurality of light sources irradiate the light incoming side surface of the light guide plate with light. The one or more optical sheets are laminated on the exit surface side of the light guide plate. The bottom frame and the top frame accommodate the light guide plate, the light source, and the optical sheet. A gap is provided between the light guide plate and any side surface of the optical sheet on the non-light receiving side with the inner surface of the side wall of the bottom frame. The light guide plate and the end of the optical sheet are sandwiched between the eaves forming the opening of the top frame and the floor of the bottom frame. A reflective layer is formed on any side surface of the light guide plate on the non-light receiving side where the gap is provided.
　本発明の一態様に係る面状照明装置は、端光を有効に抑制することができる。 The planar lighting device according to one aspect of the present invention can effectively suppress end light.
図１は、一実施形態にかかる面状照明装置の外観斜視図である。FIG. 1 is an external perspective view of the planar lighting device according to the embodiment. 図２は、図１における面状照明装置のＹ－Ｙ端面図である。FIG. 2 is a YY end view of the planar lighting device in FIG. 図３Ａは、比較例にかかる面状照明装置の構成例を示す端面図である。FIG. 3A is an end view showing a configuration example of the planar lighting device according to the comparative example. 図３Ｂは、面状照明装置の出射面を正面から見た状態と４５°斜め手前方向から見た状態とを示す図である。FIG. 3B is a diagram showing a state in which the exit surface of the planar lighting device is viewed from the front and a state in which the emission surface of the planar lighting device is viewed from a 45 ° oblique front direction. 図４Ａは、比較例の面状照明装置に遮光部を追加した状態を示す端面図である。FIG. 4A is an end view showing a state in which a light-shielding portion is added to the planar lighting device of the comparative example. 図４Ｂは、面状照明装置の出射面を正面から見た状態と４５°斜め手前方向から見た状態とを示す図である。FIG. 4B is a diagram showing a state in which the exit surface of the planar lighting device is viewed from the front and a state in which the emission surface of the planar lighting device is viewed from a 45 ° oblique front direction. 図５は、遮光部がない状態とある状態とで、面状照明装置の出射面を正面から見た状態における端部付近を横切る位置と輝度との関係の例を示す図である。FIG. 5 is a diagram showing an example of the relationship between the position crossing the vicinity of the end portion and the brightness when the exit surface of the planar lighting device is viewed from the front in a state without a light-shielding portion and a state with a light-shielding portion. 図６は、遮光部がない状態とある状態とで、面状照明装置の出射面を４５°斜め手前方向から見た状態における端部付近を横切る位置と輝度との関係の例を示す図である。FIG. 6 is a diagram showing an example of the relationship between the brightness and the position crossing the vicinity of the end portion when the exit surface of the planar lighting device is viewed from the front direction at an angle of 45 ° in the state without the light-shielding portion and in the state with the light-shielding portion. is there. 図７Ａは、面状照明装置において、反射層を設けない場合と、各種の素材による反射層を設けた場合における、出射面を４５°斜め手前方向から見た状態を示す図である。FIG. 7A is a diagram showing a state in which the exit surface is viewed from a 45 ° obliquely front direction in the case where the reflective layer is not provided and the case where the reflective layer made of various materials is provided in the planar lighting device. 図７Ｂは、出射面を４５°斜め手前方向から見た状態における端部付近を横切る位置（図７Ａの破線部分）と輝度との関係の例を示す図である。FIG. 7B is a diagram showing an example of the relationship between the position crossing the vicinity of the end portion (broken line portion in FIG. 7A) and the brightness when the exit surface is viewed from the front direction at an angle of 45 °. 図８Ａは、面状照明装置において、反射層を設けない場合と、各種の素材による反射層を設けた場合における、出射面を正面から見た状態を示す図である。FIG. 8A is a diagram showing a state in which the exit surface is viewed from the front when the reflective layer is not provided and when the reflective layer is provided with various materials in the planar lighting device. 図８Ｂは、出射面を正面から見た状態における端部付近を横切る位置（図８Ａの破線部分）と輝度との関係の例を示す図である。FIG. 8B is a diagram showing an example of the relationship between the position crossing the vicinity of the end portion (broken line portion in FIG. 8A) and the brightness when the exit surface is viewed from the front.
　以下、実施形態に係る面状照明装置について図面を参照して説明する。なお、この実施形態によりこの発明が限定されるものではない。また、図面における各要素の寸法の関係、各要素の比率などは、現実と異なる場合がある。図面の相互間においても、互いの寸法の関係や比率が異なる部分が含まれている場合がある。また、１つの実施形態や変形例に記載された内容は、原則として他の実施形態や変形例にも同様に適用される。 Hereinafter, the planar lighting device according to the embodiment will be described with reference to the drawings. The present invention is not limited to this embodiment. In addition, the relationship between the dimensions of each element in the drawing, the ratio of each element, and the like may differ from the reality. Even between drawings, there may be parts with different dimensional relationships and ratios. Further, in principle, the contents described in one embodiment or modification are similarly applied to other embodiments or modifications.
　図１は、一実施形態にかかる面状照明装置１の外観斜視図である。図１において、説明の便宜上、図の左右方向をＸ軸方向、図の奥行方向をＹ軸方向、図の上下方向をＺ軸方向とする。 FIG. 1 is an external perspective view of the planar lighting device 1 according to the embodiment. In FIG. 1, for convenience of explanation, the left-right direction of the figure is the X-axis direction, the depth direction of the figure is the Y-axis direction, and the vertical direction of the figure is the Z-axis direction.
　図１において、面状照明装置１は、略長方形（略正方形でも可）で略板状の外形をしており、後述する導光板等を収容する有床箱状のボトムフレーム２と、ボトムフレーム２の開口側を覆うトップフレーム３とから筐体が構成されている。トップフレーム３には略矩形状の開口部３ａにより出射面４が設けられており、面状照明装置１の内部から外部に向かって光が照射されるようになっている。ボトムフレーム２およびトップフレーム３は、ダイカストや板金等により形成されている。車載用のナビゲーション装置やインジケータ等のバックライトとして面状照明装置１が用いられる場合、液晶表示装置等は出射面４の側に装着される。 In FIG. 1, the planar lighting device 1 has a substantially rectangular shape (may be a substantially square shape) and has a substantially plate-like outer shape, and has a floor box-shaped bottom frame 2 for accommodating a light guide plate and the like, which will be described later, and a bottom frame. The housing is composed of a top frame 3 that covers the opening side of 2. The top frame 3 is provided with an exit surface 4 by a substantially rectangular opening 3a, so that light is emitted from the inside to the outside of the surface illumination device 1. The bottom frame 2 and the top frame 3 are formed of die casting, sheet metal, or the like. When the planar lighting device 1 is used as a backlight for an in-vehicle navigation device, an indicator, or the like, the liquid crystal display device or the like is mounted on the exit surface 4.
　図２は、図１における面状照明装置１のＹ－Ｙ端面図である。図２において、ボトムフレーム２は、床部２ａと、この床部２ａの周囲の４辺を囲む側壁２ｂとを有している。ボトムフレーム２の床部２ａ上には、反射シート５、導光板６、光学シート７、８、９が順に積層されている。反射シート５は、導光板６から床部２ａ側に漏れた光を反射して、導光板６に戻すためのものである。ボトムフレーム２の床部２ａの内面に白色の塗装等が施されて反射特性が良好な場合は、反射シート５が省略される場合もある。 FIG. 2 is a YY end view of the planar lighting device 1 in FIG. In FIG. 2, the bottom frame 2 has a floor portion 2a and a side wall 2b surrounding four sides around the floor portion 2a. A reflective sheet 5, a light guide plate 6, and optical sheets 7, 8 and 9 are laminated in this order on the floor portion 2a of the bottom frame 2. The reflective sheet 5 is for reflecting the light leaked from the light guide plate 6 to the floor portion 2a side and returning it to the light guide plate 6. If the inner surface of the floor portion 2a of the bottom frame 2 is painted white and has good reflection characteristics, the reflection sheet 5 may be omitted.
　導光板６は、アクリル等の透明な樹脂により形成されており、一の側面（入光側面）から入射された光を全面に導き、一の主面から出射する。導光板６の、非入光側の３辺の全てまたはいずれかの側面には、反射層６ａが設けられている。反射層６ａは、導光板６の内部からの光を導光板６の外部に漏らさないためのものである。導光板６からいったん漏れた光を導光板６に戻すのは困難であるため、反射層６ａにより導光板６から可能な限り光を漏らさないようにしている。ただし、導光板６の非入光側の側面に反射層６ａを設けることで、反射層６ａによる光の吸収や散乱によって出射面４への輝度の低下が生じやすいことから、単に光を漏らさないようにするだけではなく、反射層６ａに到来した光のほぼ全てを反射することが重要となる。 The light guide plate 6 is made of a transparent resin such as acrylic, and guides the light incident from one side surface (light entry side surface) to the entire surface and emits it from one main surface. Reflective layers 6a are provided on all or any of the three sides of the light guide plate 6 on the non-light receiving side. The reflective layer 6a is for preventing light from the inside of the light guide plate 6 from leaking to the outside of the light guide plate 6. Since it is difficult to return the light once leaked from the light guide plate 6 to the light guide plate 6, the reflective layer 6a prevents the light from leaking from the light guide plate 6 as much as possible. However, by providing the reflective layer 6a on the side surface of the light guide plate 6 on the non-light receiving side, the brightness of the light emitting surface 4 is likely to decrease due to the absorption and scattering of light by the reflective layer 6a, so that the light is not simply leaked. It is important not only to do so, but also to reflect almost all the light that has reached the reflective layer 6a.
　反射層６ａによる具体的な効果については後述するが、全反射によるものと拡散反射によるものとを用いることができる。全反射によるものとしては、銀やアルミ等の金属を蒸着したシート（テープ）を接着したり、導光板６の側面に直接に銀やアルミ等の金属を蒸着したりすることによって実現することができる。シート（テープ）を接着する場合、接着材（接着層）による光の散乱や吸収を防止するために、光の散乱や吸収の少ない、例えば、アクリル系の接着材を用いることが望ましい。なお、薄い両面テープであれば、両面テープを構成する基材の影響もほとんどないことが確認されているが、基材の影響を確実に除くために、シート（テープ）に接着材を直接吹き付けたり塗布したりしてもよい。この場合、導光板６の側面の位置を基材の厚さ分トップフレーム３の開口部３ａから離すことができる。これらによって、端光をより一層有効に抑制することができる。また、拡散反射によるものとしては、白色のＰＥＴ（polyethylene　terephthalate）材のシート（テープ）等を接着することによって実現することができる。 The specific effect of the reflective layer 6a will be described later, but one due to total reflection and one due to diffuse reflection can be used. The total internal reflection can be realized by adhering a sheet (tape) on which a metal such as silver or aluminum is vapor-deposited, or by depositing a metal such as silver or aluminum directly on the side surface of the light guide plate 6. it can. When adhering a sheet (tape), it is desirable to use, for example, an acrylic adhesive having less light scattering or absorption in order to prevent light scattering or absorption by the adhesive (adhesive layer). It has been confirmed that if the double-sided tape is thin, there is almost no influence of the base material that constitutes the double-sided tape, but in order to surely eliminate the influence of the base material, the adhesive is directly sprayed on the sheet (tape). Or may be applied. In this case, the position of the side surface of the light guide plate 6 can be separated from the opening 3a of the top frame 3 by the thickness of the base material. As a result, the end light can be suppressed more effectively. Further, the diffuse reflection can be realized by adhering a sheet (tape) or the like of a white PET (polyethylene terephthalate) material.
　光学シート７は、例えば、拡散シートである。光学シート８は、例えば、プリズムシートである。光学シート９は、例えば、輝度上昇フィルム（ＤＢＥＦ：Dual　Brightness　Enhancement　Film）である。なお、導光板６の出射面側に配置される光学シートの枚数は３枚に限られない。 The optical sheet 7 is, for example, a diffusion sheet. The optical sheet 8 is, for example, a prism sheet. The optical sheet 9 is, for example, a brightness increasing film (DBEF: Dual Brightness Enhancement Film). The number of optical sheets arranged on the exit surface side of the light guide plate 6 is not limited to three.
　導光板６および光学シート７、８、９の非入光側の端部とボトムフレーム２の側壁２ｂとの間には、温度変化による導光板６および光学シート７、８、９の伸縮を許容するために、隙間が形成されている。また、導光板６および光学シート７、８、９の非入光側の端部は、トップフレーム３の額縁を形成する庇部３ｂと、ボトムフレーム２の床部２ａとの間に挟持されるようになっている。 Allows expansion and contraction of the light guide plate 6 and the optical sheets 7, 8 and 9 due to temperature changes between the non-light receiving side ends of the light guide plate 6 and the optical sheets 7, 8 and 9 and the side wall 2b of the bottom frame 2. Therefore, a gap is formed. Further, the end portions of the light guide plate 6 and the optical sheets 7, 8 and 9 on the non-light receiving side are sandwiched between the eaves portion 3b forming the frame of the top frame 3 and the floor portion 2a of the bottom frame 2. It has become like.
　一方、導光板６の入光側の構成として、ボトムフレーム２の側壁２ｂには、ＬＥＤ（Light　Emitting　Diode）等による光源１１が例えば一列に複数配置された基板１０が固定され、光源１１の発光面が導光板６の側面（入光側面）と対向するようになっている。なお、トップビュータイプ（天面から発光するタイプ）のＬＥＤ等による光源１１の場合を図示しているが、トップビュータイプに代えて、側面から発光するサイドビュータイプのＬＥＤ等を光源１１として用いてもよい。この場合、基板１０の面は導光板６の入光側面と直交して配置されることになる。 On the other hand, as a configuration on the light receiving side of the light guide plate 6, a substrate 10 in which a plurality of light sources 11 by LEDs (Light Emitting Diodes) are arranged in a row is fixed to the side wall 2b of the bottom frame 2, and the light source 11 emits light. The surface faces the side surface (light entry side surface) of the light guide plate 6. Although the case of the light source 11 using a top view type (type that emits light from the top surface) LED or the like is shown in the figure, a side view type LED or the like that emits light from the side surface is used as the light source 11 instead of the top view type. You may. In this case, the surface of the substrate 10 is arranged orthogonal to the light entering side surface of the light guide plate 6.
　以下、面状照明装置において端光が発生する要因について比較例を用いて考察する。図３Ａは、比較例にかかる面状照明装置１’の構成例を示す端面図であり、非入光側の端部を示している。図３Ａにおいて、ボトムフレーム２’の床部２ａ’には、反射シート５’、導光板６’、光学シート７’、８’、９’が順に積み上げられて配置されている。導光板６’等の非入光側の端部とボトムフレーム２’の側壁２ｂ’の内面との間には隙間が形成され、導光板６’等の端部はトップフレーム３’の庇部３ｂ’とボトムフレーム２’の床部２ａ’とにより挟持されるようになっている。また、ボトムフレーム２’の側壁２ｂ’の内面には、白色のＰＥＴ材のシート（テープ）等による反射部１２’が設けられている。反射部１２’としては、反射シート５’を側壁２ｂ’まで延ばして折り曲げることで、反射シート５’と反射部１２’とを一体化する場合もある。入光側の構成は、図２と同様である。 Hereinafter, the factors that cause edge light in the planar lighting device will be considered using a comparative example. FIG. 3A is an end view showing a configuration example of the planar illumination device 1'according to the comparative example, and shows an end portion on the non-light receiving side. In FIG. 3A, the reflective sheet 5', the light guide plate 6', and the optical sheets 7', 8', and 9'are arranged in this order on the floor portion 2a'of the bottom frame 2'. A gap is formed between the non-light receiving side end of the light guide plate 6'and the inner surface of the side wall 2b' of the bottom frame 2', and the end of the light guide plate 6'and the like is the eaves of the top frame 3'. It is sandwiched between the 3b'and the floor portion 2a'of the bottom frame 2'. Further, on the inner surface of the side wall 2b'of the bottom frame 2', a reflecting portion 12'by a white PET material sheet (tape) or the like is provided. As the reflective portion 12', the reflective sheet 5'and the reflective portion 12'may be integrated by extending and bending the reflective sheet 5'to the side wall 2b'. The configuration on the incoming light side is the same as in FIG.
　図３Ａにおいて、ユーザが出射面を斜め手前方向から覗き込んだときに観測される端光の到来経路としては、破線Ａ、Ｂ、Ｃによるものが考えられる。破線Ａは、導光板６’の側面から漏れ出た光が、ボトムフレーム２’の側壁２ｂ’の内面との間の隙間を介して反射部１２’に入射して反射し、光学シート９’とトップフレーム３’の庇部３ｂ’との間のクリアランス（Ｚクリアランス）内を反射して出てくるものである。破線Ｂは、導光板６’の側面から漏れ出た光が、ボトムフレーム２’の側壁２ｂ’の内面との間の隙間を介して反射部１２’に入射して反射し、光学シート７’、８’、９’のいずれかを貫通した後にＺクリアランス内を反射して出てくるものである。破線Ｃは、導光板６’の端部の反射シート５’側の角部の輝きが、導光板６’、光学シート７’、８’、９’を通して出てくるものである。 In FIG. 3A, the arrival path of the end light observed when the user looks into the exit surface from the diagonally front direction is considered to be due to the broken lines A, B, and C. The broken line A indicates that the light leaking from the side surface of the light guide plate 6'is incident on the reflecting portion 12'through the gap between the side wall 2b'of the bottom frame 2'and the light guide plate 6'and is reflected, and is reflected by the optical sheet 9'. It is reflected in the clearance (Z clearance) between the top frame 3'and the eaves 3b' of the top frame 3'. In the broken line B, the light leaking from the side surface of the light guide plate 6'is incident on the reflecting portion 12'through the gap between the side wall 2b'of the bottom frame 2'and the optical sheet 7'. , 8', 9', and then reflected in the Z clearance. The broken line C indicates that the brilliance of the corner portion of the light guide plate 6'on the reflective sheet 5'side comes out through the light guide plate 6', the optical sheets 7', 8', and 9'.
　図３Ｂは、図３Ａの面状照明装置１’の出射面を正面から見た状態（上段）と４５°斜め手前方向から見た状態（下段）とを示す図である。上段の正面から見た状態では分からないが、下段の４５°斜め手前方向から見た状態では、端部付近Ｅに図において横方向に延びる線状の端光が発生している。 FIG. 3B is a diagram showing a state in which the exit surface of the planar lighting device 1'in FIG. 3A is viewed from the front (upper row) and a state in which the exit surface is viewed from a 45 ° oblique front direction (lower row). Although it is not clear when viewed from the front of the upper row, when viewed from the front direction at an angle of 45 ° in the lower row, linear end light extending in the lateral direction is generated near the end portion E in the figure.
　図４Ａは、比較例の面状照明装置１’に遮光部１３’を追加した状態を示す端面図であり、導光板６’の非入光側の端部と光学シート７’の端部との間に白色のＰＥＴ材等からなる遮光部１３’が挟まれ、遮光部１３’は反射部１２’に接するまで延在されている。これにより、図３Ａにおける破線Ａ、Ｂの経路が遮断されることになる。なお、遮光部１３’は、図４Ａにおける手前側の端から奥行方向に幅Ｗだけ設けられているものとしている。 FIG. 4A is an end view showing a state in which a light-shielding portion 13'is added to the planar illumination device 1'of the comparative example, and includes an end portion of the light guide plate 6'on the non-light receiving side and an end portion of the optical sheet 7'. A light-shielding portion 13'made of a white PET material or the like is sandwiched between the light-shielding portions 13', and the light-shielding portion 13'extends until it comes into contact with the reflective portion 12'. As a result, the paths of the broken lines A and B in FIG. 3A are blocked. The light-shielding portion 13'is provided with a width W in the depth direction from the front end in FIG. 4A.
　図４Ｂは、図４Ａの面状照明装置１’の出射面を正面から見た状態（上段）と４５°斜め手前方向から見た状態（下段）とを示す図である。上段の正面から見た状態ではわからないが、下段の４５°斜め手前方向から見た状態では、端部付近Ｅにおける線状の端光が、遮光部１３’が設けられた幅Ｗの領域では消失している。 FIG. 4B is a diagram showing a state in which the exit surface of the planar lighting device 1'in FIG. 4A is viewed from the front (upper row) and a state in which the exit surface of the planar illumination device 1'in FIG. 4A is viewed from a 45 ° diagonally front direction (lower row). It is not clear when viewed from the front of the upper row, but when viewed from the 45 ° diagonally front direction of the lower row, the linear end light in the vicinity of the end E disappears in the region of the width W where the light-shielding portion 13'is provided. doing.
　図５は、遮光部１３’がない状態とある状態とで、面状照明装置１’の出射面を正面から見た状態における端部付近を横切る位置と輝度との関係の例を示す図である。図６は、遮光部１３’がない状態とある状態とで、面状照明装置１’の出射面を４５°斜め手前方向から見た状態における端部付近を横切る位置と輝度との関係の例を示す図である。端部付近を横切る位置は、図３Ｂ、図４Ｂにおいて、上下方向に一点鎖線で示した線上の位置であり、出射面の外側の額縁上に原点が置かれている。 FIG. 5 is a diagram showing an example of the relationship between the brightness and the position crossing the vicinity of the end portion when the exit surface of the planar lighting device 1'is viewed from the front in the state without the light-shielding portion 13'and in the state with the light-shielding portion 13'. is there. FIG. 6 shows an example of the relationship between the position crossing the vicinity of the end portion and the brightness when the exit surface of the planar lighting device 1'is viewed from the front direction at an angle of 45 ° in the state without the light-shielding portion 13'and in the state with the light-shielding portion 13'. It is a figure which shows. The position crossing the vicinity of the end portion is a position on a line indicated by a chain line in the vertical direction in FIGS. 3B and 4B, and the origin is placed on the frame outside the exit surface.
　図５において、遮光部１３’がない状態の面状照明装置１’（Initial）と、遮光部１３’がある状態の面状照明装置１’（w/PET）とで、輝度の差はほとんどない。しかし、図６において、遮光部１３’がない状態（Initial）では、Ｐ１において端光による輝度の上昇が発生しているが、遮光部１３’がある状態（w/PET）では輝度の上昇はない。このことから、端光の発生の要因は、ほとんどが図３Ａにおける破線Ａ、Ｂの経路によるものと判断することができる。 In FIG. 5, there is almost no difference in brightness between the planar illumination device 1'(Initial) without the light-shielding portion 13'and the planar illumination device 1'(w / PET) with the light-shielding portion 13'. Absent. However, in FIG. 6, in the state without the light-shielding portion 13'(Initial), the brightness increases due to the edge light in P1, but in the state with the light-shielding portion 13'(w / PET), the brightness increases. Absent. From this, it can be determined that most of the causes of the generation of the end light are due to the paths of the broken lines A and B in FIG. 3A.
　以上のことから、図４Ａにおける遮光部１３’により端光の発生を抑制できることが分かったが、遮光部１３’を設けることは困難である。すなわち、導光板６’や光学シート７’、８’、９’は温度変化によって伸縮するため、それらの端部とボトムフレーム２’の側壁２ｂ’との間に遮光部１３’を安定して配置することは困難だからである。そのため、図２の面状照明装置１では、導光板６の、非入光側の３辺の全てまたはいずれかの側面には、導光板６に一体に反射層６ａが設けられるものとしている。 From the above, it was found that the light-shielding portion 13'in FIG. 4A can suppress the generation of end light, but it is difficult to provide the light-shielding portion 13'. That is, since the light guide plate 6'and the optical sheets 7', 8', and 9'expand and contract due to temperature changes, the light-shielding portion 13'is stabilized between their ends and the side wall 2b'of the bottom frame 2'. This is because it is difficult to arrange. Therefore, in the planar illumination device 1 of FIG. 2, a reflection layer 6a is provided integrally with the light guide plate 6 on all or any of the three sides of the light guide plate 6 on the non-light receiving side.
　次に、導光板６の反射層６ａとして、具体的にどのような素材を用いるのが適切であるかについて考察する。 Next, we will consider what kind of material is specifically suitable for the reflective layer 6a of the light guide plate 6.
　図７Ａは、面状照明装置１において、反射層６ａを設けない場合と、各種の素材による反射層６ａを設けた場合における、出射面を４５°斜め手前方向から見た状態を示す図である。図７Ａにおいて、「INITIAL」は反射層６ａが設けられていない場合（代わりに図３Ａのように反射部１２’が設けられている場合）、「白ＰＥＴ」は反射層６ａとして白色のＰＥＴ材が両面テープで貼り付けられている場合、「Ａｌ蒸着テープ」は反射層６ａとしてアルミニウムが蒸着されたテープが両面テープで貼り付けられている場合、「Ａｇ反射テープ」は、反射層６ａとして銀が蒸着されたテープが両面テープで貼り付けられている場合である。「白ＰＥＴ」の場合は拡散反射、「Ａｌ蒸着テープ」と「Ａｇ反射テープ」の場合は正反射となる。なお、「Ａｌ蒸着テープ」の反射率は約９０％、「Ａｇ反射テープ」の反射率は約９７％である。 FIG. 7A is a diagram showing a state in which the exit surface is viewed from a 45 ° obliquely front direction in the case where the reflective layer 6a is not provided and the case where the reflective layer 6a made of various materials is provided in the planar lighting device 1. .. In FIG. 7A, "INITIAL" is a case where the reflective layer 6a is not provided (instead, when a reflective portion 12'is provided as shown in FIG. 3A), "white PET" is a white PET material as the reflective layer 6a. Is affixed with double-sided tape, the "Al vapor-deposited tape" is used as the reflective layer 6a. When the tape with aluminum vapor-deposited is attached with the double-sided tape, the "Ag reflective tape" is silver as the reflective layer 6a. This is the case where the tape on which is vapor-deposited is attached with double-sided tape. In the case of "white PET", it is diffuse reflection, and in the case of "Al vapor deposition tape" and "Ag reflection tape", it is specular reflection. The reflectance of the "Al-deposited tape" is about 90%, and the reflectance of the "Ag reflective tape" is about 97%.
　図７Ｂは、出射面を４５°斜め手前方向から見た状態における端部付近を横切る位置（図７Ａの破線部分）と輝度との関係の例を示す図である。図７Ｂから分かるように、反射層６ａを設けない「INITIAL」ではＰ２において上昇していた輝度が、反射層６ａを設けた場合にはいずれの素材においても上昇せず、端光が抑制されている。このことから、端光の抑制という観点からは、「白ＰＥＴ」「Ａｌ蒸着テープ」「Ａｇ反射テープ」のいずれの素材を反射層６ａに用いてもよいことが分かる。なお、端光が発生していた部分の輝度がより低いという観点からは、正反射となる「Ａｌ蒸着テープ」および「Ａｇ反射テープ」が好ましい。 FIG. 7B is a diagram showing an example of the relationship between the position crossing the vicinity of the end portion (broken line portion in FIG. 7A) and the brightness when the exit surface is viewed from the front direction at an angle of 45 °. As can be seen from FIG. 7B, the brightness increased in P2 in "INITIAL" without the reflective layer 6a does not increase in any material when the reflective layer 6a is provided, and the edge light is suppressed. There is. From this, it can be seen that any material of "white PET", "Al vapor deposition tape", and "Ag reflective tape" may be used for the reflective layer 6a from the viewpoint of suppressing edge light. From the viewpoint that the brightness of the portion where the edge light is generated is lower, "Al-deposited tape" and "Ag-reflecting tape" that provide specular reflection are preferable.
　図８Ａは、面状照明装置１において、反射層６ａを設けない場合と、各種の素材による反射層６ａを設けた場合における、出射面を正面から見た状態を示す図である。図８Ｂは、出射面を正面から見た状態における端部付近を横切る位置（図８Ａの破線部分）と輝度との関係の例を示す図である。図８Ｂから分かるように、Ｐ３において「Ａｌ蒸着テープ」の場合に２～３％の輝度の低下がみられる。これは、「Ａｌ蒸着テープ」の反射率が約９０％ということによるものと考えられる。よって、図７Ｂの結果と図８Ｂの結果とを考慮すると、正反射となる「Ａｇ反射テープ」が最も好ましいと考えられる。 FIG. 8A is a diagram showing a state in which the exit surface is viewed from the front when the reflective layer 6a is not provided and when the reflective layer 6a made of various materials is provided in the planar lighting device 1. FIG. 8B is a diagram showing an example of the relationship between the position crossing the vicinity of the end portion (broken line portion in FIG. 8A) and the brightness when the exit surface is viewed from the front. As can be seen from FIG. 8B, in the case of "Al-deposited tape" in P3, a decrease in brightness of 2 to 3% is observed. It is considered that this is because the reflectance of the "Al-deposited tape" is about 90%. Therefore, considering the result of FIG. 7B and the result of FIG. 8B, it is considered that the "Ag reflective tape" having a specular reflection is the most preferable.
　以上、本発明の実施形態について説明したが、本発明は上記実施形態に限定されるものではなく、その趣旨を逸脱しない限りにおいて種々の変更が可能である。 Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.
　以上のように、実施形態に係る面状照明装置は、入光側面から入光する導光板と、導光板の入光側面に光を照射する複数の光源と、導光板の出射面側に積層された１以上の光学シートと、導光板、光源および光学シートを収容するボトムフレームおよびトップフレームとを備え、導光板および光学シートの非入光側のいずれかの側面にはボトムフレームの側壁の内面との間に隙間が設けられ、トップフレームの開口部を形成する庇部とボトムフレームの床部との間に導光板および光学シートの端部が挟持され、導光板の非入光側の隙間が設けられたいずれかの側面には、反射層が形成されている。これにより、端光を有効に抑制することができる。 As described above, the planar illumination device according to the embodiment is laminated with a light guide plate that receives light from the light entrance side surface, a plurality of light sources that irradiate the light entrance side surface of the light guide plate, and a light guide plate on the exit surface side. One or more optical sheets, and a bottom frame and a top frame accommodating a light guide plate, a light source, and an optical sheet are provided, and a side wall of the bottom frame is provided on any side surface of the light guide plate and the optical sheet on the non-light receiving side. A gap is provided between the inner surface and the edge of the light guide plate and the optical sheet between the eaves forming the opening of the top frame and the floor of the bottom frame. A reflective layer is formed on any side surface provided with a gap. Thereby, the end light can be effectively suppressed.
　また、反射層は、正反射層である。これにより、拡散反射に比べて端光をより有効に抑制することができる。 Also, the reflective layer is a specular reflective layer. As a result, the edge light can be suppressed more effectively than the diffuse reflection.
　また、正反射層は、銀の蒸着による層を含む。これにより、他の素材に比べて端光をより有効に抑制することができる。 The specular reflection layer includes a layer made by vapor deposition of silver. As a result, the end light can be suppressed more effectively than other materials.
　また、正反射層は、アルミニウムの蒸着による層を含む。これにより、銀の蒸着による層を含む場合よりは若干劣るが、端光を有効に抑制することができる。 The specular reflection layer includes a layer made by vapor deposition of aluminum. As a result, edge light can be effectively suppressed, although it is slightly inferior to the case where a layer formed by vapor deposition of silver is included.
　また、反射層は、拡散反射層である。これにより、正反射の場合よりは若干劣るが、端光を有効に抑制することができる。 Also, the reflective layer is a diffuse reflective layer. As a result, the edge light can be effectively suppressed, although it is slightly inferior to the case of specular reflection.
　また、拡散反射層は、白色のＰＥＴ材による層を含む。これにより、正反射の場合よりは若干劣るが、端光を有効に抑制することができる。 The diffuse reflection layer includes a layer made of white PET material. As a result, the edge light can be effectively suppressed, although it is slightly inferior to the case of specular reflection.
　また、庇部と床部との間に挟持される導光板および光学シートの端部と、庇部との間にはクリアランスが設けられる。これにより、導光板および光学シートの伸縮を許容することができる。 In addition, a clearance is provided between the edge of the light guide plate and the optical sheet sandwiched between the eaves and the floor and the eaves. Thereby, expansion and contraction of the light guide plate and the optical sheet can be allowed.
　また、上記実施の形態により本発明が限定されるものではない。上述した各構成要素を適宜組み合わせて構成したものも本発明に含まれる。また、さらなる効果や変形例は、当業者によって容易に導き出すことができる。よって、本発明のより広範な態様は、上記の実施の形態に限定されるものではなく、様々な変更が可能である。 Further, the present invention is not limited by the above-described embodiment. The present invention also includes a configuration in which the above-mentioned components are appropriately combined. Further, further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspect of the present invention is not limited to the above-described embodiment, and various modifications can be made.
　１　面状照明装置，２　ボトムフレーム，３　トップフレーム，３ａ　開口部，３ｂ　庇部，４　出射面，５　反射シート，６　導光板，６ａ　反射層，７～９　光学シート，１０　基板，１１　光源 1 planar lighting device, 2 bottom frame, 3 top frame, 3a opening, 3b eaves, 4 exit surface, 5 reflective sheet, 6 light guide plate, 6a reflective layer, 7-9 optical sheet, 10 substrate, 11 light source

Claims (7)

  1. 　入光側面から入光する導光板と、
    　前記導光板の入光側面に光を照射する複数の光源と、
    　前記導光板の出射面側に積層された１以上の光学シートと、
    　前記導光板、前記光源および前記光学シートを収容するボトムフレームおよびトップフレームと、
    を備え、
    　前記導光板および前記光学シートの非入光側のいずれかの側面には前記ボトムフレームの側壁の内面との間に隙間が設けられ、
    　前記トップフレームの開口部を形成する庇部と前記ボトムフレームの床部との間に前記導光板および前記光学シートの端部が挟持され、
    　前記導光板の非入光側の前記隙間が設けられたいずれかの側面には、反射層が形成されている、
    面状照明装置。     A light guide plate that receives light from the side of the light entry and
    A plurality of light sources that irradiate the light incoming side surface of the light guide plate with light,
    One or more optical sheets laminated on the exit surface side of the light guide plate, and
    A bottom frame and a top frame accommodating the light guide plate, the light source, and the optical sheet,
    With
    A gap is provided between the light guide plate and any side surface of the optical sheet on the non-light receiving side with the inner surface of the side wall of the bottom frame.
    The light guide plate and the end of the optical sheet are sandwiched between the eaves forming the opening of the top frame and the floor of the bottom frame.
    A reflective layer is formed on any side surface of the light guide plate on the non-light receiving side where the gap is provided.
    Planar lighting device.
  2. 　前記反射層は、正反射層である、
    請求項１に記載の面状照明装置。     The reflective layer is a specular reflective layer.
    The planar lighting device according to claim 1.
  3. 　前記正反射層は、銀の蒸着による層を含む、
    請求項２に記載の面状照明装置。     The specular reflection layer includes a layer made by vapor deposition of silver.
    The planar lighting device according to claim 2.
  4. 　前記正反射層は、アルミニウムの蒸着による層を含む、
    請求項２に記載の面状照明装置。     The specular reflection layer includes a layer made by vapor deposition of aluminum.
    The planar lighting device according to claim 2.
  5. 　前記反射層は、拡散反射層である、
    請求項１に記載の面状照明装置。     The reflective layer is a diffuse reflective layer.
    The planar lighting device according to claim 1.
  6. 　前記拡散反射層は、白色のＰＥＴ材による層を含む、
    請求項５に記載の面状照明装置。     The diffuse reflection layer includes a layer made of white PET material.
    The planar lighting device according to claim 5.
  7. 　前記庇部と前記床部との間に挟持される前記導光板および前記光学シートの端部と、前記庇部との間にはクリアランスが設けられる、
    請求項１～６のいずれか一つに記載の面状照明装置。     A clearance is provided between the edge of the light guide plate and the optical sheet sandwiched between the eaves and the floor, and the eaves.
    The planar lighting device according to any one of claims 1 to 6.
PCT/JP2020/039411 2019-12-03 2020-10-20 Planar illumination device WO2021111749A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012086511A1 (en) * 2010-12-24 2012-06-28 シャープ株式会社 Lighting unit, display unit and television receiver
JP2017204484A (en) * 2017-08-09 2017-11-16 サターン ライセンシング エルエルシーＳａｔｕｒｎ Ｌｉｃｅｎｓｉｎｇ ＬＬＣ Display device
JP2018120793A (en) * 2017-01-26 2018-08-02 シャープ株式会社 Luminaire, display device and television receiver
JP2019129066A (en) * 2018-01-24 2019-08-01 シャープ株式会社 Illumination device and display device

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4075977B2 (en) * 1999-09-10 2008-04-16 株式会社エンプラス Surface light source device and image display device including the surface light source device
CN104736919B (en) * 2012-10-26 2017-03-08 夏普株式会社 Backlight and display device
KR102429136B1 (en) * 2015-10-30 2022-08-03 엘지디스플레이 주식회사 Display device
JP6669691B2 (en) * 2017-05-11 2020-03-18 ミネベアミツミ株式会社 Planar lighting device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012086511A1 (en) * 2010-12-24 2012-06-28 シャープ株式会社 Lighting unit, display unit and television receiver
JP2018120793A (en) * 2017-01-26 2018-08-02 シャープ株式会社 Luminaire, display device and television receiver
JP2017204484A (en) * 2017-08-09 2017-11-16 サターン ライセンシング エルエルシーＳａｔｕｒｎ Ｌｉｃｅｎｓｉｎｇ ＬＬＣ Display device
JP2019129066A (en) * 2018-01-24 2019-08-01 シャープ株式会社 Illumination device and display device

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