JP4623613B2 - Image display device and surface light source device - Google Patents

Image display device and surface light source device Download PDF

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JP4623613B2
JP4623613B2 JP2000269328A JP2000269328A JP4623613B2 JP 4623613 B2 JP4623613 B2 JP 4623613B2 JP 2000269328 A JP2000269328 A JP 2000269328A JP 2000269328 A JP2000269328 A JP 2000269328A JP 4623613 B2 JP4623613 B2 JP 4623613B2
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guide plate
light guide
light
inclined surface
display device
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JP2002082622A (en
JP2002082622A5 (en
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学 高塩
浩 山崎
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Enplas Corp
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Enplas Corp
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Priority to KR1020010054441A priority patent/KR100768028B1/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
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
    • G02B6/0031—Reflecting element, sheet or layer
    • 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
    • G02F1/133524—Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133605—Direct backlight including specially adapted reflectors
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133615—Edge-illuminating devices, i.e. illuminating from the side

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Liquid Crystal (AREA)
  • Planar Illumination Modules (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)

Description

【０００１】
【発明の属する技術分野】
この発明は、携帯型電話や電子手帳等の画像表示装置及びこの画像表示装置に使用される面光源装置に関する。
【０００２】
【従来の技術】
例えば、携帯型電話の画像表示装置として使用される液晶表示装置は、液晶表示パネル（被照明部材）の裏面側に面光源装置を配置し、この面光源装置から発せられる光によって液晶表示パネルを照明するようになっている。
【０００３】
図１０は、このような従来の液晶表示装置１０１を示すものである。この液晶表示装置１０１は、導光板１０２の裏面１０３側に光源としての蛍光ランプ１０４を配置し、この蛍光ランプ１０４の光を導光板１０２の端部の傾斜面１０５に付設した反射体１０６で略直角に反射して、図１０中右方向に向かう光束が導光板１０２内部に導かれるようになっている。このような構成の液晶表示装置１０１は、蛍光ランプ１０４を導光板１０２の側面に配置する場合に比較し、蛍光ランプ１０４と液晶表示パネル１０７との間隔を広くすることができるため、蛍光ランプ１０４の熱が液晶表示パネル１０７に伝わり難く、液晶表示パネル１０７の温度上昇に起因する液晶表示パネル１０７の色むらが抑制されるようになっている（特開平４−３５５４２８号公報参照）。尚、導光板１０２、蛍光ランプ１０４、反射体１０６を備えた面光源装置１０８に液晶表示パネル１０７が組み付けられて液晶表示装置１０１が構成される。
【０００４】
【発明が解決しようとする課題】
しかしながら、このような従来の液晶表示装置１０１は、極めて薄い導光板（例えば、厚さ約１．０ｍｍ〜１．５ｍｍ）１０２の傾斜面１０５に反射体１０６としての光反射フィルムを接着固定するようになっているが、傾斜面１０５の寸法に合わせて光反射フィルムを切断し、その切断した光反射フィルム片を傾斜面１０５に接着することになるため、光反射フィルム（１０６）の接着作業が困難であり、液晶表示装置１０１の製造工数が嵩むという問題を有していた。しかも、光反射フィルム（１０６）の接着面積が狭く、光反射フィルム（１０６）が傾斜面１０５から剥がれやすいという問題をも有していた。尚、光反射フィルム（１０６）が傾斜面１０５から剥がれると、その光反射フィルム（１０６）が剥がれた部分から光が導光板１０２の外部に漏出し、光の利用効率が低下し、照明輝度が低下する。
【０００５】
そこで、本発明は、このような従来技術の問題点を解消できる構造の面光源装置及びこの面光源装置を備えた画像表示装置を提供することを目的とする。
【０００６】
【課題を解決するための手段】
請求項１の発明は、導光板の裏面側に光源が配置され、前記裏面側から前記導光板内へ入射した前記光源からの光を、前記導光板の内部側へ向けて前記導光板の内部を伝播させるように反射する角度の傾斜面が前記導光板の側面に形成され、前記傾斜面の表面側に反射部材が配置され、前記導光板の出射面に対向するように被照明部材が配置されてなる画像表示装置に関するものである。そして、前記反射部材が、導光板と被照明部材のいずれか一方に接着固定される第１部分と、前記傾斜面に密着させられる第２部分とを備えている。又、前記反射部材と前記被照明部材との間に、前記反射部材の第２部分を前記傾斜面に押し付ける弾性体が配置されるようになっている。
【０００７】
請求項２の発明は、導光板の裏面側に光源が配置され、前記裏面側から前記導光板内へ入射した前記光源からの光を、前記導光板の内部側へ向けて前記導光板の内部を伝播させるように反射する角度の傾斜面が前記導光板の側面に形成され、前記傾斜面の表面側に反射部材が配置され、前記導光板の出射面に対向するように被照明部材が配置されてなる画像表示装置に関するものである。そして、前記反射部材が、導光板と被照明部材のいずれか一方に接着固定される第１部分と、前記傾斜面に密着させられる第２部分とを備えている。そして、前記反射部材と前記被照明部材との間に、前記反射部材の第２部分を前記傾斜面に押し付ける充填材が配置されている。
【０００８】
請求項３の発明は、導光板の裏面側に光源が配置され、前記裏面側から前記導光板内へ入射した前記光源からの光を、前記導光板の内部側へ向けて前記導光板の内部を伝播させるように反射する角度の傾斜面が前記導光板の側面に形成され、前記傾斜面の表面側に反射部材が配置されてなる面光源装置に関するものである。そして、前記反射部材が、導光板の出射面に接着固定される第１部分と、前記傾斜面に密着させられる第２部分とを備えている。又、前記反射部材の第２部分の表面側に弾性体が固定されており、前記導光板の前記出射面上に被照明側部材が配置されると、該被照明部材によって前記弾性体が押圧され、前記反射部材の第２部分が前記傾斜面に前記弾性体の弾性力で押圧されるようになっている。
【０００９】
【発明の実施の形態】
以下、本発明の実施の形態を図面に基づき詳述する。
【００１０】
［第１の実施の形態］
図１〜図３は、本発明の第１の実施の形態に係る画像表示装置１を示すものである。尚、図１は、本実施の形態に係る画像表示装置１の分解斜視図である。図２は、面光源装置２に被照明部材としての液晶表示パネル３を組み付ける前の状態を示す断面図（図１のＡ−Ａ線に沿う方向の断面図）である。又、図３は、面光源装置２に液晶表示パネル３を組み付けてなる画像表示装置１の一部を示す断面図である。
【００１１】
これらの図に示すように、面光源装置２は、導光板４と、導光板４の出射面５の両端部に固定される一対の反射部材６，６と、導光板４の裏面７側の四隅に対応するようにそれぞれ配置された光源としての発光ダイオード（ＬＥＤ）８とを備えている。そして、導光板４の出射面５に対向するように液晶表示パネル３を配置して画像表示装置１が構成されている。
【００１２】
導光板４は、ＰＣ（ポリカーボネート）、ＰＭＭＡ（ポリメタクリル酸メチル）、シクロオレフィン系樹脂等の透明材料で平板状に形成されたものであり、平面形状が略矩形形状に形成されている。そして、この導光板４は、図４〜図５に詳細を示すように、四隅が面取りされ、更に、その面取り部分（側面）１０が斜めに切り取られ、傾斜面１１が形成されている。この傾斜面１１の傾斜角度θは、ＬＥＤ８から発せられた光が反射して出射面５と略平行な方向へ進行するような光成分を多くする角度に形成される。尚、本実施の形態においては、ＬＥＤ８から発せられた光が導光板４の出射面５に略直交するように導光板４に入射するので、傾斜面１１の傾斜角θが約４５度になっている。
【００１３】
反射部材６は、白色ＰＥＴ（ポリエチレンテレフタレート）等の光反射性に優れたフィルムで形成されており、導光板４に対向する面に銀が蒸着され、この銀蒸着面に接着材が塗布されている。この反射部材６は、導光板４の出射面５に接着固定される第１部分６ａと、導光板４の傾斜面１１に接着固定される第２部分６ｂとを備えている。反射部材４の第１部分６ａは、第２部分６ｂに比較して接着面積が格段に大きく、導光板４の出射面１１に確実に接着固定される。反射部材６の第２部分６ｂは、導光板４の形状に沿うように折り曲げられた状態で傾斜面１１に接着されるが、傾斜面１１との接着面積が小さく十分な接着強度が得られ難いため、反射部材６の復元力で傾斜面から剥がれやすい（図２参照）。
【００１４】
そこで、本実施の形態の画像表示装置１は、反射部材６の第２部分６ｂの液晶表示パネル３に対向する面（非接着面）に弾性体１２を固着し、この弾性体１２が面光源装置２に組み付けられた液晶表示パネル３によって押圧されるようにして、弾性体１２で反射部材６の第２部分６ｂを傾斜面１１に押し付けるようになっている。これにより、画像表示装置１の使用中において、反射部材６の第２部分６ｂが傾斜面１１から剥がれるようなことがない。又、反射部材６の第１部分６ａは、両端部にそれぞれ舌片６ｃが形成されており、傾斜面１１近傍の接着面積を十分確保できるため、反射部材６が導光板４に十分な接着強度で固定される。従って、画像表示装置１の使用中に導光板４から反射部材６の第２部分６ｂが剥がれるようなことがない。尚、本実施の形態において、弾性体１２は、略三角錐形状であるが、これに限られるものでなく、液晶表示パネル３に押圧されて反射部材６の第２部分６ｂを傾斜面１１に密着させることができるものであればよく、例えば三角柱状や半球状に形成してもよい。また、弾性体１２としては、ポリウレタンフォーム、発泡ポリオレフィン、発泡ゴム等を例示することができ、反射部材６の第２部分６ｂを傾斜面１１に押し付けることができれば、その材質は特に問われないが、液晶表示パネル３や導光板４等の他部材への負荷を考慮すると、スポンジ状の軟質フォームが好ましい。
【００１５】
導光板４の裏面７側で且つ導光板４の傾斜面１１に対応する位置、換言すれば、導光板４の裏面７側の四隅部に対向する位置に、それぞれＬＥＤ８が配置されている。このＬＥＤ８は、導光板４の出射面５に対して略垂直となる方向に光りを出射するように配置されている。
【００１６】
又、導光板４の裏面７側には、光反射性に優れたＰＥＴ等の樹脂シートから形成された反射シート１３が配置されるようになっている。そして、この反射シート１３の四隅部には、ＬＥＤ８から発せられた光の通過を可能にする切り欠き部１４がそれぞれ形成されている。このような反射シート１３は、導光板４の裏面７から漏出した光を反射して導光板４内部に戻すようになっている。尚、導光板４の裏面７側に光反射性に優れたフレームパネルが配置され（図９参照）、このフレームパネルで導光板４の裏面７側から出射する光を反射できる場合には、上記反射シート１３を省略することができる。
【００１７】
このような構成の画像表示装置１において、ＬＥＤ８から発せられた光の多くは、導光板４の内部に入射した後、傾斜面１１に接着された反射部材６で反射され、導光板４の出射面５に略平行な方向へ向きを変え、導光板４内部を伝播する。そして、導光板４内部を伝播する光のうちで、出射面５に対して臨界角以下の角度で入射する光が出射面５から導光板４の外部に出射する。ここで、本実施の形態の画像表示装置１は、導光板４の四隅からＬＥＤ８の光が入射するようになっているため、導光板４の出射面５から出射される光の輝度が均一化し、明るく高品質の面照明が可能になる。従って、本実施の形態の画像表示装置１は、液晶表示パネル３の画像が明るくて見やすく、画像表示品質が優れている。
【００１８】
以上のように、本実施の形態の画像表示装置１は、導光板４の出射面５側に液晶表示パネル３を組み付けると、導光板４の出射面５の端部に固定した反射部材６の弾性体１２が液晶表示パネル３で押圧され、その弾性体１２が反射部材６の第２部分６ｂを確実に傾斜面１１に密着させることができるため、ＬＥＤ８の光を傾斜面１１から導光板４の外部に漏出させることなく反射し、ＬＥＤ８の光を導光板４内部に確実に入射させることができる。従って、本実施の形態の画像表示装置１によれば、従来例に比較し、ＬＥＤ８（光源）の光の有効利用率が向上し、導光板４からの出射光の輝度アップが図られる。
【００１９】
又、本実施の形態の画像表示装置１は、反射部材６が導光板４の出射面５に接着固定される第１部分６ａと傾斜面１１に接着させられる第２部分６ｂとを備えているため、反射体１０６が導光板１０２の傾斜面１０５にのみ接着固定される従来例（図１０参照）に比較して、反射部材６の接着面積を大きくすることができ、反射部材６の接着固定作業が容易化し、画像表示装置１の製造工数を従来例よりも削減することが可能になる。
【００２０】
尚、傾斜面１１の形成個数及びＬＥＤ８の設置個数は、導光板４の有効発光面積や画像表示装置１の取付スペース等の設計条件に応じて適宜変更することができる。
【００２１】
［第２の実施の形態］
図６〜図８は、本発明の第２の実施の形態に係る画像表示装置２１を示すものである。尚、図６は、本実施の形態に係る画像表示装置２１の分解斜視図である。図７は、面光源装置２２に被照明部材としての液晶表示パネル２３を組み付ける前の状態を示す断面図（図６のＣ−Ｃ線に沿う方向の断面図）である。又、図８は、面光源装置２２に液晶表示パネル２３を組み付けてなる画像表示装置２１の一部を示す断面図である。
【００２２】
本実施の形態の画像表示装置２１は、導光板２４の裏面２７側に光源としての蛍光ランプ２８が配置されると共に反射シート３３が配置され、導光板２４の出射面２５側の一端部に反射部材２６が接着固定され、導光板２４の出射面２５に対向するように液晶表示パネル２３が配置されるようになっている。
【００２３】
導光板２４は、その一端部の厚みが他端部よりも厚く形成されており、図６のＣ−Ｃ線に沿って切断した断面形状が略楔形形状で且つ平面形状が矩形形状を呈しており、ＰＣ、ＰＭＭＡ、シクロオレフィン系樹脂等で形成されている。そして、この導光板２４の一端部には、側面２４ａを斜めに切り取られたような傾斜面３１が形成されている。この傾斜面３１の出射面２５に対する傾斜角度θは、蛍光ランプ２８から発せられた光の多くが導光板２４の出射面２５と略平行な方向へ反射して伝播する角度に設定される。
【００２４】
反射部材２６は、前記第１の実施の形態と同様に、白色ＰＥＴ等の光反射性に優れたフィルムで形成されており、導光板２４に対向する面に銀が蒸着され、この銀蒸着面に接着材が塗布されている。この反射部材２６は、導光板２４の出射面２５に接着固定される第１部分２６ａと、導光板２４の傾斜面３１に接着固定される第２部分２６ｂとを備えている。反射部材２６の第１部分２６ａは、第２部分２６ｂに比較して接着面積が大きく、導光板２４の出射面２５に確実に接着固定される。反射部材２６の第２部分２６ｂは、導光板２４の形状に沿うように折り曲げられた状態で傾斜面３１に接着されるが、傾斜面３１との接着面積が小さいため、反射部材２６の復元力で傾斜面３１から剥がれやすい（図７参照）。
【００２５】
そこで、本実施の形態の画像表示装置２１は、前記第１の実施の形態と同様に、反射部材２６の第２部分２６ｂの液晶表示パネル２３に対向する面（非接着面）にスポンジや発泡ゴム等の弾性体３２を固着し、この弾性体３２が面光源装置２２に組み付けられた液晶表示パネル２３によって押圧されるようにして、弾性体３２で反射部材２６の第２部分２６ｂを傾斜面３１に押し付けるようになっている。又、反射部材２６は、両端部にそれぞれ舌片２６ｃが形成されており、導光板２４の端部近傍の接着面積を十分確保できるため、反射部材２６の第１部分２６ａが導光板２４に十分な接着強度で固定される。これにより、画像表示装置２１の使用中において、反射部材２６の第２部分２６ｂが傾斜面３１から剥がれたり、反射部材２６の第１部分２６ａが出射面２５から剥がれるようなことがない。尚、本実施の形態における弾性体３２は、断面略三角形状であり、傾斜面３１の寸法に対応するような寸法に形成されている。
【００２６】
導光板２４の裏面２７側で且つ導光板２４の傾斜面３１に対応する位置、換言すれば、導光板２４の裏面２７の傾斜面３１側端部に対向する位置に蛍光ランプ２８が配置されている。この蛍光ランプ２８から発せられた光が導光板２４の裏面２７から内部に入射する。
【００２７】
又、導光板２４の裏面２７側には、光反射性に優れたＰＥＴ等の樹脂シートから形成された反射シート３３が配置されるようになっている。この反射シート３３の蛍光ランプ２８側端部は、図６に示すように、蛍光ランプ２８から発せられた光が導光板２４の傾斜面３１側端部に入射するように切り欠かれており（図６の２点鎖線部３４）、導光板２４の裏面２７の面積よりも小さく形成されている。このような反射シート３３は、導光板２４の裏面２７から漏出した光を反射して導光板２４内部に戻すようになっている。尚、導光板２４の裏面２７側に光反射性に優れたフレームパネルが配置され（図９参照）、このフレームパネルで導光板２４の裏面２７側から出射する光を反射できる場合には、上記反射シート３３を省略することができる。
【００２８】
このような構成の画像表示装置２１において、蛍光ランプ２８から発せられた光の多くは、導光板２４の内部に入射した後、傾斜面３１に接着された反射部材２６で反射され、導光板２４の出射面２５に略平行な方向へ向きを変え、導光板２４内部を伝播する。そして、導光板２４内部を伝播する光のうちで、出射面２５に対して臨界角以下の角度で入射する光が出射面２５から導光板２４の外部に出射する。ここで、本実施の形態の画像表示装置２１は、蛍光ランプ２８が導光板２４の裏面２７側に位置し、蛍光ランプ２８が液晶表示パネル２３から離れた位置にあるため、蛍光ランプ２８の熱が液晶表示パネル２３に伝達されにくい。従って、本実施の形態によれば、液晶表示パネル２３が部分的に加熱されることに起因する色ムラの発生を防止することができ、均一で高品質の画像表示が可能になる。
【００２９】
以上のように、本実施の形態の画像表示装置２１は、導光板２４の出射面２５側に液晶表示パネル２３を組み付けると、導光板２４の出射面２５の端部に固定した反射部材２６の弾性体３２が液晶表示パネル２３で押圧され、その弾性体３２が反射部材２６の第２部分２６ｂを確実に傾斜面３１に密着させることができるため、蛍光ランプ２８から発せられた光を傾斜面３１から外部に漏出させることなく反射し、蛍光ランプ２８からの光を導光板２４内部に確実に入射させることができる。従って、本実施の形態の画像表示装置２１によれば、従来例に比較し、蛍光ランプ２８の光の有効利用率が向上し、導光板２４からの出射光の輝度アップが図られる。
【００３０】
又、本実施の形態の画像表示装置２１は、前記第１の実施の形態と同様に、反射部材２６が導光板２４の出射面２５に接着固定される第１部分２６ａと傾斜面３１に接着させられる第２部分２６ｂとを備えているため、反射体１０６が導光板１０２の傾斜面１０５にのみ接着固定される従来例（図１０参照）に比較して、反射部材２６の接着面積を大きくすることができ、反射部材２６の接着固定作業が容易化し、画像表示装置２１の製造工数を従来例よりも削減することが可能になる。
【００３１】
尚、本実施の形態において、断面略楔形形状の導光板２４を例示したが、これに限られず、平板状やその他の断面形状の導光板にも適用できる。
【００３２】
又、本実施の形態において、導光板２４の裏面２７側の一端部にのみ蛍光ランプ２８を配置する態様を例示したが、これに限られず、他の３辺のうちの少なくとも１辺に対応するように蛍光ランプ２８を設置し、複数の蛍光ランプ２８を使用して面照明を行うようにしてもよい。
【００３３】
又、本実施の形態において、弾性体３２は、断面略三角形状であるが、これに限られるものでなく、液晶表示パネル２３に押圧されて反射部材２６の第２部分２６ｂを傾斜面３１に密着させることができるものであればよく、例えば、断面略半円形状等でもよい。
【００３４】
又、本実施の形態において、弾性体３２としては、前記第１の実施の形態の弾性体１２と同様に、ポリウレタンフォーム、発泡ポリオレフィン、発泡ゴム等を例示することができ、反射部材２６の第２部分２６ｂを傾斜面３１に押し付けることができれば、その材質は特に問われないが、液晶表示パネル２３や導光板２４等の他部材への負荷を考慮すると、スポンジ状の軟質フォームが好ましい。
【００３５】
［第３の実施の形態］
図９は、本発明の第３の実施の形態を示すものであり、前記第１及び第２の実施の形態の変形例を示すものである。
【００３６】
即ち、本実施の形態の画像表示装置４１は、前記第１及び第２の実施の形態において、弾性体１２，３２の代わりに充填材４２を使用した点に特徴を有している。詳しくは、反射部材４３の第１部分４３ａと第２部分４３ｂを導光板４４の出射面４５と傾斜面４６に接着した後、導光板４４や液晶表示パネル（被照明部材）４７等を収容するフレーム４８と反射部材４３との隙間に充填材（スポンジ，ゴム等の弾性体や、隙間の形状に合わせて変形することができるガム状，粘土状，ゲル状の可塑性材料）４２が収容され、液晶表示パネル４７がフレーム４８に組み付けられた際に、充填材４２で反射部材４３を傾斜面４６に押し付けるようになっている。ここで、導光板４４の裏面５０を支持するフレームパネル５１が光反射性に優れた白色に形成されており、その端部に導光板４４側に向けて開口する蛍光ランプ（光源）５２の収容凹部５３が形成されている。尚、傾斜面４６は、導光板４４の側面４４ａに形成されている。
【００３７】
このような構成の本実施の形態は、前記第１及び第２の実施の形態と同様の効果を奏し得る。
【００３８】
尚、上記の各実施の形態において、反射部材６，２６，４３の第１部分６ａ，２６ａ，４３ａを導光板４，２４，４４の出射面５，２５，４５側に接着固定する態様を例示したが、これに限られず、反射部材６，２６，４３の第１部分６ａ，２６ａ，４３ａを被照明部材としての液晶表示パネル３，２３，４７に接着固定するようにしてもよい。又、弾性体１２，３２や充填材４２によって反射部材６，２６，４３の第２部分６ｂ，２６ｂ，４３ｂを傾斜面１１，３１，４６に十分に密着させることができるのであれば、当該第２部分６ｂ，２６ｂ，４３ｂへの接着材の塗布は必要に応じて省略することができる。
【００３９】
又、上記第３の実施の形態において、フレームパネル５１が導光板４４の裏面５０側に配置されない場合には、前記第１及び第２の実施の形態のように、導光板４４の裏面５０側に反射シートが配置される。
【００４０】
又、上記各実施の形態において、被照明部材として液晶表示パネル３，２３，４７を例示したが、これに限られるものでなく、導光板４，２４，４４から出射した光で照射される部材（例えば、拡散シートやプリズムシート等）も被照明部材に含まれる。
【００４１】
【発明の効果】
以上のように、本発明は、反射部材が導光板の出射面に接着固定される第１部分と傾斜面に密着させられる第２部分とを備えているため、反射フィルムが導光板の傾斜面にのみ接着固定される従来例に比較して、反射部材の接着面積を大きくすることができ、反射部材の接着固定作業が容易化し、面光源装置やこの面光源装置を備えた画像表示装置の製造工数を従来例よりも削減することが可能になる。
【００４２】
又、本発明は、反射部材の第２部分と被照明部材との間に配置された弾性体や充填材によって反射部材の第２部分が傾斜面に押し付けられるようになっているため、反射部材の第２部分が傾斜面から剥がれるようなことがなく、光源からの光を効率よく導光板内部に入射させることができる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態に係る画像表示装置の分解斜視図である。
【図２】本発明の第１の実施の形態に係る面光源装置に被照明部材としての液晶表示パネルを組み付ける前の状態を示す断面図（図１のＡ−Ａ線に沿う方向の断面図）である。
【図３】本発明の第１の実施の形態に係る面光源装置に液晶表示パネルを組み付けてなる画像表示装置の一部を示す断面図である。
【図４】本発明の第１の実施の形態に係る導光板の平面図である。
【図５】図４の導光板の側面側から見た図である。図５（ａ）が導光板の側面図であり、図５（ｂ）が図４のＢ方向から見た部分的側面図である。
【図６】本発明の第２の実施の形態に係る画像表示装置の分解斜視図である。
【図７】本発明の第２の実施の形態に係る面光源装置に被照明部材としての液晶表示パネルを組み付ける前の状態を示す断面図（図６のＣ−Ｃ線に沿う方向の断面図）である。
【図８】本発明の第２の実施の形態に係る面光源装置に液晶表示パネルを組み付けてなる画像表示装置の一部を示す断面図である。
【図９】本発明の第３の実施の形態に係る画像表示装置の部分的断面図である。
【図１０】従来の液晶表示装置の部分的断面図である。
【符号の説明】
１，２１，４１……画像表示装置、２，２２……面光源装置、３，２３，４７……液晶表示パネル（被照明部材）、４，２４，４４……導光板、５，２５，４５……出射面、６，２６，４３……反射部材、６ａ，２６ａ，４３ａ……第１部分、６ｂ，２６ｂ，４３ｂ……第２部分、７，２７，５０……裏面、８……ＬＥＤ（光源）、１０……面取り部分（側面）、１１，３１，４６……傾斜面、１２，３２……弾性体、２４ａ……側面、２８，５２……蛍光ランプ（光源）、４２……充填材、４４ａ……側面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image display device such as a portable telephone and an electronic notebook, and a surface light source device used in the image display device.
[0002]
[Prior art]
For example, a liquid crystal display device used as an image display device for a portable telephone has a surface light source device disposed on the back side of a liquid crystal display panel (illuminated member), and the liquid crystal display panel is formed by light emitted from the surface light source device. It comes to illuminate.
[0003]
FIG. 10 shows such a conventional liquid crystal display device 101. In this liquid crystal display device 101, a fluorescent lamp 104 as a light source is disposed on the back surface 103 side of the light guide plate 102, and the light from the fluorescent lamp 104 is substantially reflected by a reflector 106 attached to the inclined surface 105 at the end of the light guide plate 102. A light beam reflected at a right angle and directed rightward in FIG. 10 is guided into the light guide plate 102. In the liquid crystal display device 101 having such a configuration, the interval between the fluorescent lamp 104 and the liquid crystal display panel 107 can be widened as compared with the case where the fluorescent lamp 104 is arranged on the side surface of the light guide plate 102. Therefore, the color unevenness of the liquid crystal display panel 107 due to the temperature rise of the liquid crystal display panel 107 is suppressed (see Japanese Patent Laid-Open No. 4-355428). A liquid crystal display panel 107 is assembled to a surface light source device 108 including a light guide plate 102, a fluorescent lamp 104, and a reflector 106 to constitute a liquid crystal display device 101.
[0004]
[Problems to be solved by the invention]
However, in such a conventional liquid crystal display device 101, a light reflecting film as the reflector 106 is bonded and fixed to an inclined surface 105 of an extremely thin light guide plate 102 (for example, a thickness of about 1.0 mm to 1.5 mm). However, since the light reflecting film is cut in accordance with the dimension of the inclined surface 105 and the cut light reflecting film piece is bonded to the inclined surface 105, the light reflecting film (106) is bonded. It is difficult and the manufacturing man-hour of the liquid crystal display device 101 is increased. In addition, the adhesive area of the light reflecting film (106) is narrow, and the light reflecting film (106) has a problem that it is easily peeled off from the inclined surface 105. When the light reflecting film (106) is peeled off from the inclined surface 105, light leaks from the portion where the light reflecting film (106) is peeled off to the outside of the light guide plate 102, the light use efficiency is lowered, and the illumination brightness is reduced. descend.
[0005]
SUMMARY OF THE INVENTION An object of the present invention is to provide a surface light source device having a structure capable of solving such problems of the prior art and an image display device including the surface light source device.
[0006]
[Means for Solving the Problems]
The invention according to claim 1, the light source is arranged on the back side of the light guide plate, the interior of the light from the light source from the back side incident to the light guide plate within the light guide plate toward the inner side of the light guide plate An inclined surface that reflects the light so as to propagate is formed on the side surface of the light guide plate, a reflective member is disposed on the surface side of the inclined surface, and an illuminated member is disposed so as to face the output surface of the light guide plate The present invention relates to an image display apparatus. The reflective member includes a first portion that is bonded and fixed to either the light guide plate or the illumination target member, and a second portion that is brought into close contact with the inclined surface. Further, an elastic body that presses the second portion of the reflecting member against the inclined surface is disposed between the reflecting member and the illuminated member.
[0007]
According to a second aspect of the invention, the light source is arranged on the back side of the light guide plate, the interior of the light from the light source from the back side incident to the light guide plate within the light guide plate toward the inner side of the light guide plate An inclined surface that reflects the light so as to propagate is formed on the side surface of the light guide plate, a reflective member is disposed on the surface side of the inclined surface, and an illuminated member is disposed so as to face the output surface of the light guide plate The present invention relates to an image display apparatus. The reflective member includes a first portion that is bonded and fixed to either the light guide plate or the illumination target member, and a second portion that is brought into close contact with the inclined surface. And the filler which presses the 2nd part of the said reflection member against the said inclined surface is arrange | positioned between the said reflection member and the said to-be-illuminated member.
[0008]
The invention according to claim 3, the light source is arranged on the back side of the light guide plate, the interior of the light from the light source from the back side incident to the light guide plate within the light guide plate toward the inner side of the light guide plate The present invention relates to a surface light source device in which an inclined surface having an angle of reflection so as to propagate is formed on a side surface of the light guide plate, and a reflecting member is disposed on the surface side of the inclined surface. The reflecting member includes a first portion that is bonded and fixed to the light exit surface of the light guide plate and a second portion that is brought into close contact with the inclined surface. Further, an elastic body is fixed to the surface side of the second portion of the reflecting member, and when the illuminated side member is disposed on the emission surface of the light guide plate, the elastic body is pressed by the illuminated member. The second portion of the reflecting member is pressed against the inclined surface by the elastic force of the elastic body.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0010]
[First Embodiment]
1 to 3 show an image display device 1 according to a first embodiment of the present invention. FIG. 1 is an exploded perspective view of the image display device 1 according to the present embodiment. FIG. 2 is a cross-sectional view (a cross-sectional view taken along the line AA in FIG. 1) showing a state before the liquid crystal display panel 3 as a member to be illuminated is assembled to the surface light source device 2. FIG. 3 is a cross-sectional view showing a part of an image display device 1 in which the liquid crystal display panel 3 is assembled to the surface light source device 2.
[0011]
As shown in these drawings, the surface light source device 2 includes a light guide plate 4, a pair of reflecting members 6 and 6 fixed to both ends of the light exit surface 5 of the light guide plate 4, and a rear surface 7 side of the light guide plate 4. Light emitting diodes (LEDs) 8 serving as light sources are provided so as to correspond to the four corners. Then, the liquid crystal display panel 3 is arranged so as to face the light exit surface 5 of the light guide plate 4 to constitute the image display device 1.
[0012]
The light guide plate 4 is formed in a flat plate shape using a transparent material such as PC (polycarbonate), PMMA (polymethyl methacrylate), or cycloolefin resin, and the planar shape is formed in a substantially rectangular shape. As shown in detail in FIGS. 4 to 5, the light guide plate 4 has four corners chamfered, and further chamfered portions (side surfaces) 10 are cut obliquely to form inclined surfaces 11. The inclination angle θ of the inclined surface 11 is formed to an angle that increases the light component such that the light emitted from the LED 8 is reflected and travels in a direction substantially parallel to the emission surface 5. In the present embodiment, since the light emitted from the LED 8 is incident on the light guide plate 4 so as to be substantially orthogonal to the emission surface 5 of the light guide plate 4, the inclination angle θ of the inclined surface 11 is about 45 degrees. ing.
[0013]
The reflecting member 6 is formed of a film having excellent light reflectivity such as white PET (polyethylene terephthalate), and silver is vapor-deposited on a surface facing the light guide plate 4, and an adhesive is applied to the silver vapor-deposited surface. Yes. The reflecting member 6 includes a first portion 6 a that is bonded and fixed to the light exit surface 5 of the light guide plate 4 and a second portion 6 b that is bonded and fixed to the inclined surface 11 of the light guide plate 4. The first portion 6a of the reflecting member 4 has a remarkably larger bonding area than the second portion 6b, and is securely bonded and fixed to the emission surface 11 of the light guide plate 4. The second portion 6b of the reflecting member 6 is bonded to the inclined surface 11 while being bent along the shape of the light guide plate 4. However, the bonding area with the inclined surface 11 is small and it is difficult to obtain sufficient adhesive strength. Therefore, it is easy to peel off from the inclined surface by the restoring force of the reflecting member 6 (see FIG. 2).
[0014]
Therefore, in the image display device 1 of the present embodiment, the elastic body 12 is fixed to the surface (non-adhesive surface) of the second portion 6b of the reflecting member 6 that faces the liquid crystal display panel 3, and the elastic body 12 is a surface light source. The second portion 6 b of the reflecting member 6 is pressed against the inclined surface 11 by the elastic body 12 so as to be pressed by the liquid crystal display panel 3 assembled in the device 2. Thereby, the second portion 6 b of the reflecting member 6 is not peeled off from the inclined surface 11 during use of the image display device 1. Further, the first portion 6a of the reflecting member 6 has tongue pieces 6c formed at both ends thereof, so that a sufficient bonding area in the vicinity of the inclined surface 11 can be secured, so that the reflecting member 6 has a sufficient adhesive strength to the light guide plate 4. It is fixed with. Therefore, the second portion 6 b of the reflecting member 6 is not peeled off from the light guide plate 4 during use of the image display device 1. In the present embodiment, the elastic body 12 has a substantially triangular pyramid shape. However, the elastic body 12 is not limited to this, and the second portion 6b of the reflecting member 6 is pressed to the inclined surface 11 by being pressed by the liquid crystal display panel 3. Any material can be used as long as it can be in close contact with each other. The elastic body 12 may be exemplified by polyurethane foam, foamed polyolefin, foamed rubber, etc. The material is not particularly limited as long as the second portion 6b of the reflecting member 6 can be pressed against the inclined surface 11. Considering the load on other members such as the liquid crystal display panel 3 and the light guide plate 4, a sponge-like flexible foam is preferable.
[0015]
The LEDs 8 are arranged at positions corresponding to the inclined surface 11 of the light guide plate 4 on the back surface 7 side of the light guide plate 4, in other words, at positions facing the four corners on the back surface 7 side of the light guide plate 4. The LED 8 is arranged to emit light in a direction substantially perpendicular to the emission surface 5 of the light guide plate 4.
[0016]
Further, on the back surface 7 side of the light guide plate 4, a reflection sheet 13 formed of a resin sheet such as PET having excellent light reflectivity is arranged. And the notch part 14 which enables passage of the light emitted from LED8 is formed in the four corner parts of this reflection sheet 13, respectively. Such a reflection sheet 13 reflects light leaked from the back surface 7 of the light guide plate 4 and returns it to the inside of the light guide plate 4. In addition, when the frame panel excellent in light reflectivity is arrange | positioned at the back surface 7 side of the light-guide plate 4 (refer FIG. 9) and the light radiate | emitted from the back surface 7 side of the light-guide plate 4 can be reflected with this frame panel, the above-mentioned The reflection sheet 13 can be omitted.
[0017]
In the image display device 1 having such a configuration, most of the light emitted from the LED 8 is incident on the inside of the light guide plate 4, then reflected by the reflecting member 6 bonded to the inclined surface 11, and emitted from the light guide plate 4. The direction is changed in a direction substantially parallel to the surface 5 and propagates in the light guide plate 4. Of the light propagating through the inside of the light guide plate 4, light incident at an angle less than the critical angle with respect to the emission surface 5 is emitted from the emission surface 5 to the outside of the light guide plate 4. Here, in the image display device 1 according to the present embodiment, the light of the LED 8 is incident from the four corners of the light guide plate 4, so that the luminance of the light emitted from the emission surface 5 of the light guide plate 4 is uniformized. Bright and high quality surface lighting is possible. Therefore, the image display device 1 of the present embodiment has a bright and easy-to-see image on the liquid crystal display panel 3 and excellent image display quality.
[0018]
As described above, when the liquid crystal display panel 3 is assembled on the light exit surface 5 side of the light guide plate 4, the image display device 1 of the present embodiment has the reflective member 6 fixed to the end of the light exit surface 5 of the light guide plate 4. The elastic body 12 is pressed by the liquid crystal display panel 3, and the elastic body 12 can reliably bring the second portion 6 b of the reflecting member 6 into close contact with the inclined surface 11, so that the light of the LED 8 is transmitted from the inclined surface 11 to the light guide plate 4. Therefore, the light from the LED 8 can be reliably incident on the inside of the light guide plate 4. Therefore, according to the image display device 1 of the present embodiment, the effective utilization rate of the light of the LED 8 (light source) is improved and the brightness of the emitted light from the light guide plate 4 is increased as compared with the conventional example.
[0019]
In addition, the image display device 1 according to the present embodiment includes a first portion 6 a in which the reflecting member 6 is bonded and fixed to the emission surface 5 of the light guide plate 4 and a second portion 6 b that is bonded to the inclined surface 11. Therefore, compared to the conventional example (see FIG. 10) in which the reflector 106 is bonded and fixed only to the inclined surface 105 of the light guide plate 102, the bonding area of the reflecting member 6 can be increased, and the reflecting member 6 is bonded and fixed. The work is facilitated, and the number of manufacturing steps of the image display device 1 can be reduced as compared with the conventional example.
[0020]
The number of inclined surfaces 11 formed and the number of LEDs 8 installed can be appropriately changed according to the design conditions such as the effective light emitting area of the light guide plate 4 and the mounting space of the image display device 1.
[0021]
[Second Embodiment]
6 to 8 show an image display device 21 according to a second embodiment of the present invention. FIG. 6 is an exploded perspective view of the image display device 21 according to the present embodiment. FIG. 7 is a cross-sectional view (a cross-sectional view taken along the line CC in FIG. 6) showing a state before the liquid crystal display panel 23 as an illuminated member is assembled to the surface light source device 22. FIG. 8 is a cross-sectional view showing a part of an image display device 21 in which the liquid crystal display panel 23 is assembled to the surface light source device 22.
[0022]
In the image display device 21 of the present embodiment, a fluorescent lamp 28 as a light source is disposed on the back surface 27 side of the light guide plate 24 and a reflection sheet 33 is disposed, and is reflected at one end portion on the light exit surface 25 side of the light guide plate 24. The member 26 is bonded and fixed, and the liquid crystal display panel 23 is disposed so as to face the light exit surface 25 of the light guide plate 24.
[0023]
The light guide plate 24 is formed such that its one end is thicker than the other end, the cross-sectional shape cut along the line CC in FIG. 6 is a substantially wedge shape, and the planar shape is a rectangular shape. It is made of PC, PMMA, cycloolefin resin or the like. At one end of the light guide plate 24, an inclined surface 31 is formed such that the side surface 24a is cut obliquely. The inclination angle θ of the inclined surface 31 with respect to the emission surface 25 is set to an angle at which much of the light emitted from the fluorescent lamp 28 is reflected and propagated in a direction substantially parallel to the emission surface 25 of the light guide plate 24.
[0024]
As in the first embodiment, the reflecting member 26 is formed of a film having excellent light reflectivity such as white PET, and silver is deposited on the surface facing the light guide plate 24. An adhesive is applied to the surface. The reflecting member 26 includes a first portion 26 a that is bonded and fixed to the light emission surface 25 of the light guide plate 24, and a second portion 26 b that is bonded and fixed to the inclined surface 31 of the light guide plate 24. The first portion 26 a of the reflecting member 26 has a larger bonding area than the second portion 26 b, and is securely bonded and fixed to the emission surface 25 of the light guide plate 24. The second portion 26b of the reflecting member 26 is bonded to the inclined surface 31 while being bent along the shape of the light guide plate 24. However, since the bonding area with the inclined surface 31 is small, the restoring force of the reflecting member 26 is It is easy to peel off from the inclined surface 31 (see FIG. 7).
[0025]
Therefore, in the image display device 21 of the present embodiment, as in the first embodiment, a sponge or foam is formed on the surface (non-adhesive surface) of the second portion 26b of the reflecting member 26 facing the liquid crystal display panel 23. An elastic body 32 such as rubber is fixed, and the elastic body 32 is pressed by the liquid crystal display panel 23 assembled to the surface light source device 22 so that the second portion 26b of the reflecting member 26 is inclined by the elastic body 32. It is designed to be pressed against 31. In addition, since the reflecting member 26 has tongue pieces 26 c formed at both ends, and a sufficient bonding area in the vicinity of the end of the light guide plate 24 can be secured, the first portion 26 a of the reflecting member 26 is sufficient for the light guide plate 24. It is fixed with a good adhesive strength. Thereby, the second portion 26 b of the reflecting member 26 is not peeled off from the inclined surface 31 and the first portion 26 a of the reflecting member 26 is not peeled off from the emitting surface 25 during use of the image display device 21. In addition, the elastic body 32 in the present embodiment has a substantially triangular cross section, and is formed in a size corresponding to the size of the inclined surface 31.
[0026]
The fluorescent lamp 28 is arranged on the back surface 27 side of the light guide plate 24 and at a position corresponding to the inclined surface 31 of the light guide plate 24, in other words, a position facing the end portion on the inclined surface 31 side of the back surface 27 of the light guide plate 24. Yes. Light emitted from the fluorescent lamp 28 is incident on the inside from the back surface 27 of the light guide plate 24.
[0027]
Further, on the back surface 27 side of the light guide plate 24, a reflection sheet 33 formed of a resin sheet such as PET having excellent light reflectivity is arranged. As shown in FIG. 6, the reflection sheet 33 is cut out so that the light emitted from the fluorescent lamp 28 is incident on the inclined surface 31 side end of the light guide plate 24 as shown in FIG. 6 is formed smaller than the area of the back surface 27 of the light guide plate 24. Such a reflection sheet 33 reflects light leaked from the back surface 27 of the light guide plate 24 and returns it to the inside of the light guide plate 24. In addition, when the frame panel excellent in light reflectivity is arranged on the back surface 27 side of the light guide plate 24 (see FIG. 9) and the light emitted from the back surface 27 side of the light guide plate 24 can be reflected by this frame panel, The reflection sheet 33 can be omitted.
[0028]
In the image display device 21 having such a configuration, most of the light emitted from the fluorescent lamp 28 is incident on the inside of the light guide plate 24 and then reflected by the reflecting member 26 bonded to the inclined surface 31. The direction is changed in a direction substantially parallel to the emission surface 25 of the light and propagates in the light guide plate 24. Of the light propagating through the light guide plate 24, light incident on the emission surface 25 at an angle less than the critical angle is emitted from the emission surface 25 to the outside of the light guide plate 24. Here, in the image display device 21 of the present embodiment, the fluorescent lamp 28 is located on the back surface 27 side of the light guide plate 24, and the fluorescent lamp 28 is located away from the liquid crystal display panel 23. Is not easily transmitted to the liquid crystal display panel 23. Therefore, according to the present embodiment, it is possible to prevent color unevenness due to partial heating of the liquid crystal display panel 23 and to display a uniform and high-quality image.
[0029]
As described above, when the liquid crystal display panel 23 is assembled on the light exit surface 25 side of the light guide plate 24, the image display device 21 of the present embodiment has the reflection member 26 fixed to the end of the light exit surface 25 of the light guide plate 24. Since the elastic body 32 is pressed by the liquid crystal display panel 23 and the elastic body 32 can securely bring the second portion 26b of the reflecting member 26 into close contact with the inclined surface 31, the light emitted from the fluorescent lamp 28 is inclined. Therefore, the light from the fluorescent lamp 28 can be reliably incident on the inside of the light guide plate 24. Therefore, according to the image display device 21 of the present embodiment, the effective utilization rate of the light of the fluorescent lamp 28 is improved and the brightness of the emitted light from the light guide plate 24 is increased as compared with the conventional example.
[0030]
Further, in the image display device 21 of the present embodiment, the reflective member 26 is bonded to the inclined surface 31 and the first portion 26a that is bonded and fixed to the emission surface 25 of the light guide plate 24, as in the first embodiment. Since the second portion 26b is provided, the reflective member 26 has a larger bonding area than the conventional example (see FIG. 10) in which the reflector 106 is bonded and fixed only to the inclined surface 105 of the light guide plate 102. This facilitates the bonding and fixing work of the reflecting member 26, and the number of manufacturing steps of the image display device 21 can be reduced as compared with the conventional example.
[0031]
In the present embodiment, the light guide plate 24 having a substantially wedge-shaped cross section is illustrated, but the present invention is not limited to this, and the present invention can be applied to a light guide plate having a flat plate shape or other cross sectional shapes.
[0032]
Moreover, in this Embodiment, although the aspect which arrange | positions the fluorescent lamp 28 only in the one end part by the side of the back surface 27 of the light-guide plate 24 was illustrated, it is not restricted to this, It respond | corresponds to at least 1 side of other 3 sides. As described above, the fluorescent lamp 28 may be installed, and surface illumination may be performed using a plurality of fluorescent lamps 28.
[0033]
In the present embodiment, the elastic body 32 has a substantially triangular cross section. However, the elastic body 32 is not limited to this, and the second portion 26b of the reflecting member 26 is pressed to the inclined surface 31 by being pressed by the liquid crystal display panel 23. Any material can be used as long as it can be in close contact with each other.
[0034]
In the present embodiment, the elastic body 32 can be exemplified by polyurethane foam, foamed polyolefin, foamed rubber, and the like, similar to the elastic body 12 of the first embodiment. The material is not particularly limited as long as the two portions 26b can be pressed against the inclined surface 31, but a sponge-like flexible foam is preferable in consideration of loads on other members such as the liquid crystal display panel 23 and the light guide plate 24.
[0035]
[Third Embodiment]
FIG. 9 shows a third embodiment of the present invention, and shows a modification of the first and second embodiments.
[0036]
That is, the image display device 41 of the present embodiment is characterized in that the filler 42 is used instead of the elastic bodies 12 and 32 in the first and second embodiments. Specifically, after the first portion 43a and the second portion 43b of the reflecting member 43 are bonded to the emission surface 45 and the inclined surface 46 of the light guide plate 44, the light guide plate 44, the liquid crystal display panel (illuminated member) 47, and the like are accommodated. In the gap between the frame 48 and the reflecting member 43, a filler (an elastic body such as sponge or rubber, or a gum-like, clay-like, or gel-like plastic material that can be deformed according to the shape of the gap) 42 is accommodated. When the liquid crystal display panel 47 is assembled to the frame 48, the reflecting member 43 is pressed against the inclined surface 46 by the filler 42. Here, the frame panel 51 that supports the back surface 50 of the light guide plate 44 is formed in white with excellent light reflectivity, and accommodates a fluorescent lamp (light source) 52 that opens toward the light guide plate 44 at the end thereof. A recess 53 is formed. The inclined surface 46 is formed on the side surface 44 a of the light guide plate 44.
[0037]
This embodiment having such a configuration can achieve the same effects as those of the first and second embodiments.
[0038]
In each of the above-described embodiments, the first portions 6a, 26a, 43a of the reflecting members 6, 26, 43 are illustrated as being bonded and fixed to the exit surfaces 5, 25, 45 side of the light guide plates 4, 24, 44. However, the present invention is not limited to this, and the first portions 6a, 26a, 43a of the reflecting members 6, 26, 43 may be bonded and fixed to the liquid crystal display panels 3, 23, 47 as illumination members. If the second portions 6b, 26b, 43b of the reflecting members 6, 26, 43 can be sufficiently adhered to the inclined surfaces 11, 31, 46 by the elastic bodies 12, 32 and the filler 42, the first Application of the adhesive material to the two portions 6b, 26b, and 43b can be omitted as necessary.
[0039]
Further, in the third embodiment, when the frame panel 51 is not disposed on the back surface 50 side of the light guide plate 44, the back surface 50 side of the light guide plate 44 as in the first and second embodiments. A reflective sheet is disposed on the surface.
[0040]
In each of the above embodiments, the liquid crystal display panels 3, 23, and 47 are exemplified as the members to be illuminated. However, the present invention is not limited to this, and the members irradiated with the light emitted from the light guide plates 4, 24, and 44 are used. (For example, a diffusion sheet, a prism sheet, etc.) are also included in the illuminated member.
[0041]
【The invention's effect】
As described above, according to the present invention, since the reflective member includes the first portion that is bonded and fixed to the light exit surface of the light guide plate and the second portion that is closely attached to the inclined surface, the reflective film is the inclined surface of the light guide plate. Compared to the conventional example in which only the adhesive member is bonded and fixed, the bonding area of the reflecting member can be increased, the bonding and fixing work of the reflecting member is facilitated, and the surface light source device and the image display device equipped with the surface light source device are improved. Manufacturing man-hours can be reduced as compared with the conventional example.
[0042]
Further, in the present invention, since the second portion of the reflecting member is pressed against the inclined surface by the elastic body or the filler disposed between the second portion of the reflecting member and the illuminated member, the reflecting member The second portion is not peeled off from the inclined surface, and the light from the light source can be efficiently incident on the inside of the light guide plate.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an image display apparatus according to a first embodiment of the present invention.
2 is a cross-sectional view showing a state before the liquid crystal display panel as a member to be illuminated is assembled to the surface light source device according to the first embodiment of the present invention (a cross-sectional view along the line AA in FIG. 1); ).
FIG. 3 is a cross-sectional view showing a part of an image display device in which a liquid crystal display panel is assembled to the surface light source device according to the first embodiment of the present invention.
FIG. 4 is a plan view of the light guide plate according to the first embodiment of the present invention.
5 is a view of the light guide plate of FIG. 4 as viewed from the side. FIG. 5A is a side view of the light guide plate, and FIG. 5B is a partial side view seen from the direction B of FIG.
FIG. 6 is an exploded perspective view of an image display device according to a second embodiment of the present invention.
FIG. 7 is a cross-sectional view showing a state before a liquid crystal display panel as an illuminated member is assembled to a surface light source device according to a second embodiment of the present invention (a cross-sectional view taken along the line CC in FIG. 6); ).
FIG. 8 is a cross-sectional view showing a part of an image display device in which a liquid crystal display panel is assembled to a surface light source device according to a second embodiment of the present invention.
FIG. 9 is a partial cross-sectional view of an image display device according to a third embodiment of the present invention.
FIG. 10 is a partial cross-sectional view of a conventional liquid crystal display device.
[Explanation of symbols]
1, 21, 41 ... Image display device, 2, 22 ... Surface light source device, 3, 23, 47 ... Liquid crystal display panel (illuminated member), 4, 24, 44 ... Light guide plate, 5, 25, 45... Exit surface, 6, 26, 43... Reflective member, 6a, 26a, 43a... First portion, 6b, 26b, 43b... Second portion, 7, 27, 50. LED (light source), 10... Chamfered portion (side surface), 11, 31, 46 .. inclined surface, 12, 32... Elastic body, 24a .. side surface, 28, 52. ... Filler, 44a ... Side

Claims (3)

導光板の裏面側に光源が配置され、前記裏面側から前記導光板内へ入射した前記光源からの光を、前記導光板の内部側へ向けて前記導光板の内部を伝播させるように反射する角度の傾斜面が前記導光板の側面に形成され、前記傾斜面の表面側に反射部材が配置され、前記導光板の出射面に対向するように被照明部材が配置されてなる画像表示装置において、
前記反射部材が、導光板と被照明部材のいずれか一方に接着固定される第１部分と、前記傾斜面に密着させられる第２部分とを備え、
前記反射部材と前記被照明部材との間に、前記反射部材の第２部分を前記傾斜面に押し付ける弾性体が配置されたことを特徴とする画像表示装置。Light source is disposed on the back side of the light guide plate, the light from the light source incident to the light guide plate in from the back side, reflected so as to propagate within the light guide plate toward the inner side of the light guide plate In an image display device, an inclined surface having an angle is formed on a side surface of the light guide plate, a reflecting member is disposed on a surface side of the inclined surface, and an illuminated member is disposed so as to face the exit surface of the light guide plate. ,
The reflection member includes a first portion that is bonded and fixed to either the light guide plate or the illuminated member, and a second portion that is closely attached to the inclined surface,
An image display device, wherein an elastic body that presses the second portion of the reflecting member against the inclined surface is disposed between the reflecting member and the illuminated member. 導光板の裏面側に光源が配置され、前記裏面側から前記導光板内へ入射した前記光源からの光を、前記導光板の内部側へ向けて前記導光板の内部を伝播させるように反射する角度の傾斜面が前記導光板の側面に形成され、前記傾斜面の表面側に反射部材が配置され、前記導光板の出射面に対向するように被照明部材が配置されてなる画像表示装置において、
前記反射部材が、導光板と被照明部材のいずれか一方に接着固定される第１部分と、前記傾斜面に密着させられる第２部分とを備え、
前記反射部材と前記被照明部材との間に、前記反射部材の第２部分を前記傾斜面に押し付ける充填材が配置されたことを特徴とする画像表示装置。Light source is disposed on the back side of the light guide plate, the light from the light source incident to the light guide plate in from the back side, reflected so as to propagate within the light guide plate toward the inner side of the light guide plate In an image display device, an inclined surface having an angle is formed on a side surface of the light guide plate, a reflecting member is disposed on a surface side of the inclined surface, and an illuminated member is disposed so as to face the exit surface of the light guide plate. ,
The reflection member includes a first portion that is bonded and fixed to either the light guide plate or the illuminated member, and a second portion that is closely attached to the inclined surface,
An image display device, wherein a filler for pressing the second portion of the reflecting member against the inclined surface is disposed between the reflecting member and the illuminated member. 導光板の裏面側に光源が配置され、前記裏面側から前記導光板内へ入射した前記光源からの光を、前記導光板の内部側へ向けて前記導光板の内部を伝播させるように反射する角度の傾斜面が前記導光板の側面に形成され、前記傾斜面の表面側に反射部材が配置されてなる面光源装置であって、
前記反射部材が、導光板の出射面に接着固定される第１部分と、前記傾斜面に密着させられる第２部分とを備え、
前記反射部材の第２部分の表面側に弾性体が固定され、
前記導光板の前記出射面上に被照明側部材が配置されると、該被照明部材によって前記弾性体が押圧され、前記反射部材の第２部分が前記傾斜面に前記弾性体の弾性力で押圧されることを特徴とする面光源装置。Light source is disposed on the back side of the light guide plate, the light from the light source incident to the light guide plate in from the back side, reflected so as to propagate within the light guide plate toward the inner side of the light guide plate An angle inclined surface is formed on a side surface of the light guide plate, and a surface light source device in which a reflecting member is disposed on the surface side of the inclined surface,
The reflective member includes a first portion that is bonded and fixed to the light exit surface of the light guide plate, and a second portion that is closely attached to the inclined surface,
An elastic body is fixed to the surface side of the second portion of the reflecting member,
When the illuminated side member is disposed on the emission surface of the light guide plate, the elastic body is pressed by the illuminated member, and the second portion of the reflecting member is applied to the inclined surface by the elastic force of the elastic body. A surface light source device that is pressed.
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