TW201235614A - Planar light source device and stereo display device - Google Patents

Planar light source device and stereo display device Download PDF

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Publication number
TW201235614A
TW201235614A TW100142171A TW100142171A TW201235614A TW 201235614 A TW201235614 A TW 201235614A TW 100142171 A TW100142171 A TW 100142171A TW 100142171 A TW100142171 A TW 100142171A TW 201235614 A TW201235614 A TW 201235614A
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TW
Taiwan
Prior art keywords
light
guide plate
light guide
light source
front side
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TW100142171A
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Chinese (zh)
Inventor
Yukihiro Takahashi
Masayuki Shinohara
Gouo Kurata
Hiroyuki Miyamoto
Morihisa Ota
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Omron Tateisi Electronics Co
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Publication of TW201235614A publication Critical patent/TW201235614A/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
    • G02B6/0028—Light guide, e.g. taper
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
    • G02B30/20—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes
    • G02B30/26—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the autostereoscopic type
    • G02B30/27—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the autostereoscopic type involving lenticular arrays
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
    • G02B30/20—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes
    • G02B30/34—Stereoscopes providing a stereoscopic pair of separated images corresponding to parallactically displaced views of the same object, e.g. 3D slide viewers
    • G02B30/35—Stereoscopes providing a stereoscopic pair of separated images corresponding to parallactically displaced views of the same object, e.g. 3D slide viewers using reflective optical elements in the optical path between the images and the observer
    • 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
    • G02B6/0075—Arrangements of multiple light guides
    • G02B6/0076—Stacked arrangements of multiple light guides of the same or different cross-sectional area
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
    • H04N13/30—Image reproducers
    • H04N13/302—Image reproducers for viewing without the aid of special glasses, i.e. using autostereoscopic displays
    • H04N13/31—Image reproducers for viewing without the aid of special glasses, i.e. using autostereoscopic displays using parallax barriers
    • H04N13/312—Image reproducers for viewing without the aid of special glasses, i.e. using autostereoscopic displays using parallax barriers the parallax barriers being placed behind the display panel, e.g. between backlight and spatial light modulator [SLM]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
    • H04N13/30—Image reproducers
    • H04N13/302—Image reproducers for viewing without the aid of special glasses, i.e. using autostereoscopic displays
    • H04N13/32—Image reproducers for viewing without the aid of special glasses, i.e. using autostereoscopic displays using arrays of controllable light sources; using moving apertures or moving light sources
    • 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
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0036—2-D arrangement of prisms, protrusions, indentations or roughened surfaces
    • 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
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0038—Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0045—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it by shaping at least a portion of the light guide
    • G02B6/0046—Tapered light guide, e.g. wedge-shaped light guide
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—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
    • G02B6/0053—Prismatic sheet or layer; Brightness enhancement element, sheet or layer
    • 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
    • G02B6/0058—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide
    • G02B6/0061—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide to provide homogeneous light output intensity
    • 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

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Planar Illumination Modules (AREA)
  • Liquid Crystal (AREA)

Abstract

A planar light source device is constructed by overlapping two light-guiding plates, such that luminous brightness of light emitting from one light-guiding plate positioned on the rear side and luminous brightness of light emitting from the other light-guiding plate positioned on the front side become more even when observing. Two light-guiding plates 32a, 32b are overlapped in such a way that one light-guiding plate 32a is positioned on the front side, and the other light-guiding plate 32b is positioned on the rear side. One light source 41a is arranged opposite to a light emitting end face of the light-guiding plate 32a and another light source 41b is arranged opposite to a light emitting end face of the light-guiding plate 32b. Two light sources 41a, 41b are lighted up alternately with time division. Each brightness of two light sources 41a, 41b are different. The brightness of the light source 41b positioned on the rear side is brighter than that of the light source 41a positioned on the front side.

Description

201235614 六、發明說明： 【發明所屬之技術領域】 本發明係關於面光源裝置及立體顯示裝置。具體而 吕’係關於用以使畫像、影像進行三維顯示的立體顯示 裝置、及使用於該立體顯示裝置的面光源裝置。 【先前技術】 用以顯示所謂三維影像之立體顯示裝置，具有使用 觀察用眼鏡之方法及不使用眼鏡的方法。但在使用眼鏡 之方法中’因觀察者必須將眼鏡戴在頭部，所以不僅麻 煩還會給觀察者f來不舒適感。因此，作為立體顯示 裝置’以不使用眼鏡之方法較佳。 作為不使用眼鏡之立體顯示裝置，例如，具有專利 文獻1所揭示者、或專利文獻2所揭示者。 圖1 (A)係顯示專利文獻1揭示之立體顯示裝置1 1。在 此立體顯示裝置11中’將呈楔形之導光板l2a與同樣呈楔 形之導光板12b重疊而形成導光體12。導光板i2a與導光 板12b係以導光板i2a成為前面側且導光板12b成為背面 側的方式’隔著空氣層重疊。使導光板1 2a之厚度較厚側 的端面與導光板12b之厚度較薄側的端面之左右位置對 齊，亦使導光板12a之厚度較薄側的端面與導光板12b之 厚度較厚側的端面之左右位置對齊。左側用光源1 3 a係與 導光板12a之厚度較厚的端面對向。右側用光源Ub係與 導光板12b之厚度較厚的端面對向。另外，於導光體 之前面配置有稜鏡片14’於該稜鏡片i 4之前面配置有液 晶面板1 5。 201235614 另外，液晶面板1 5係分時地交替顯示右眼用晝像及 左眼用畫像，左側用光源i 3a係與左眼用畫像同步地發光 (此時，右側用光源1 3 b熄滅），右側用光源1 3 b係與右眼 用晝像同步地發光（此時’左側用光源l3a熄滅）。其結果 ，在立體顯示裝置11中，從左側用光源i 3a射出之左侧照 明光16 a被轉換成左眼用畫像而射入觀察者之左眼丨7 &， 從右側用光源1 3b射出之右側照明光！ 6b被轉換成右眼用 畫像而射入觀察者之右眼17b，而由觀察者辨識立體影像 〇 此時’如圖1 (B)所示，從左側光源1 3 a射出的左側照 明光1 6a係在配置於前面側的導光板1 2a的背面反射，然 後穿透導光板1 2a而從該光射出面朝前方射出；從右侧光 源1 3b射出的右側照明光1 6b係在配置於背面側的導光板 12b的背面反射，然後依序穿透導光板m及12a而朝前方 射出。另一方面，導光板12a和導光板l2b僅配置的方向 與配置的前後相異，兩者是使用相同的構造且相同的材 料。因此’從背面側的導光板12b射出的右側照明光i6b 在穿透刖面側的導光板1 2 a時，比起左側照明光】6 a會產 生多餘的吸收、散射。其結果，觀察者觀看時，會感到 從背面側的導光板12b射出之右側照明光16b的亮度比從 前面側的導光板12a射出之左側照明光l6a的亮度還低， 會有右眼所辨識的畫像與左眼所辨識的晝像不均勻之問 題。 由於專利文獻2所揭示之立體顯示用面光源裝置亦 具有與專利文獻丨相同的構造，所以同樣地，從背面側的 201235614 導光板射出之光的亮度比從前面側的導光板射出之光的 亮度更低，觀察者會感到左右畫像的亮度不均句。 [先前技術文獻] [專利文獻] [專利文獻1]曰本專利第358578 1號公報 [專利文獻2]日本特開2008-287 180號公報 【發明内容】 [發明所欲解決之課題] 本發明係有鑑於上述的技術課題而開發者，其目的 在於：於重疊兩片導光板而構成的面光源裝置中，從位 於背面側的導光板射出之光所產生的發光亮度和從位於 則面側的導光板射出之光所產生的發光亮度可讓觀察者 觀看時感到更均勻。 [解決課題之手段] 本發明之面光源裝置’係具備：一對導光板，係以 則面與背面對向的方式重疊；前面侧的光源’係與位於 别面側的導光板的一端面對向而配置；及背面側的光源 係與位於背面側的導光板的一端面對向而配置； 其特徵為： 设成僅使前述前面側的光源點亮以使光從前述前面 ^的導光板的光射出面射出時的發光亮度、和僅使前述 月面側的光源點亮以使光從前述背面側的導光板的光射 出面射出時通過前述前面側的導光板所觀察到的發光亮 度成為相同亮度。 由於係設成僅使前面側的 本發明的面光源裝置中 201235614 光源點亮以使光從 發光亮度、和僅使 導光板的光射出面 的發光亮度成為相 眼的和進入右眼的 使用於顯示立體影 右平衡的立體影像 本發明之面光 背面側的光源時之 光亮度，係高於僅 側的導光板之光射 從背面側的導光板 產生的損失可藉由 償，僅點亮前面側 的光源時之發光亮 本發明之面光 側之光源的亮度係 此貫施態樣，由於 僅點亮背面側之光 發光亮度。因此， 面側的導光板時戶斤 板的發光亮度來補 度與僅點亮背面側 前面側的導光板的 背面側的光源點亮 射出時通過前面側 同亮度，所以可縮 光的強度差。因此 像的立體顯示裝置 〇 源裝置的某實施態 前述背面侧的導光 點亮前述前面側的 出面的發光亮度。 射出的光在穿透前 提高背面側的導光 的光源時之發光亮 度的亮度差會變小 源裝置的其他實施 高於前述前面侧之 提高背面側之光源 源時之背面側的導 從背面側的導光板 產生的損失可藉由 償，僅點亮前面側 的光源時之發光亮 光射出面射出時的 以使光從背面側的 的導光板所觀察到 小進入觀察者之左 ，將此面光源裝置 時，可觀察取得左 樣中’僅點亮前述 板之光射出面的發 光源時之前述前面 根據此實施態樣， 面側的導光板時所 板的發光亮度來補 度與僅點亮背面側 0 態樣中，前述背面 光源的亮度。根據 的亮度，故可提高 光板的光射出面的 射出的光在穿透前 提高背面側的導光 的光源時之發光亮 度的亮度差會變小 為了提兩前述背面側 的光源的亮度，只要使前述背 201235614 面側的光源的光度大於前述前面側的光源的光度即 然而’若考量到穿透前面側的導光板時的最大損失 前述背面側之光源的光度較佳為前述前面側之光源 度的1. 5倍以下。 本發明的面光源裝置的另一實施態樣之前述背 的導光板，其光射出效率比前述前面側的導光板的 出效率還尚。根據此貫施態樣，從背面側的導光板 的光在穿透前面側的導光板時所產生的損失可藉由 背面側的導光板的射出效率來補償，能縮小僅前面 光源點亮時的發光亮度與僅背面側的光源點亮時的 亮度的亮度差。 為了提高背面側的導光板的射出效率較佳為 如前述前面側的導光板及前述背面側的導光板係具 成為發光區域之厚度較薄的導光板本體， · 光導入部，其至少一部分具有比前述導光板本 大的厚度，並使前述前面側或前述背面側的光源對 置於端面；以及 光移行部，使前述導光板本體和前述光導入 的方式改變厚度； 前述背面側的導光板之前述光導人部與前述 邻* :厚度差係小於前述前面側的導光板之前述 4與則述導光板本體的厚度差。 : 光板的光導入部與導光部本體的厚度差愈 二：易從光導入部與導光部本體之中間厚度變化 因此，若在背面側的導光板中前述厚度的 〇 ，則 的光 面側 光射 射出 提高 側的 發光 ，例 有· 體更 向配 連接 光板 導入 ，光 部分 變小 201235614 ，則背面側的導光板之光的漏洩會小於前面側的導光板 之光的漏洩，背面側的導光板的射出效率會變高。其結 果，可縮小點亮前面側的光源時的發光亮度與點亮背面 側的光源時的發光亮度之差。 又，此實施態樣中，較佳為前述前面侧的導光板及 前述背面側的導光板各自之前述光導入部的厚度，係與 前述前面側的導光板之導光板本體的厚度及前述背面側 的導光板之導光板本體的厚度之和相等。根據此態樣， 由於面光源裝置的整體厚度大致均勻’所以容易組裝為 背光源，能使光學片、液晶面板穩定，且生産性亦提升 。再者，在前述背面側的導光板的前述光導入部比其導 光板本體的前面更朝前方突出，且前述前面側的導光板 的前述光導入部比其導光板本體的背面更朝後方突出的 情況’較佳為前述背面側的導光板之前述光導入部與前 述導光板本體的厚度差為前述前面側的導光板之前述光 導入部與前述導光板本體的厚度差的1/4倍以上。 本發明面光源裝置之又一實施態樣之前述前面側的 導光板的穿透損失係小於前述背面側的導光板的穿透損 失°根據此實施態樣’由於前面側的導光板的穿透損失 變小’故可減少從背面側的導光板發出的光在穿透前面 側的導光板時的損失，可減少僅點亮前面側的光源時的 發光7C度與僅點亮背面側的光源時的發光亮度的亮度差 〇 為了減少前面側的導光板的穿透損失，例如，只要 於則述引面側的導光板及前述背面側的導光板各自之前 201235614 面與背面的任一者，形成擴散圖案，使前述前面側的導 光板之前述擴散圖案的圖案密度或表面粗度小於前述背 面側的導光板之前述擴散圖案的圖案密度或表面粗度即 可。若使則面側的導光板之擴散圖案的圖案密度或表面 粗度變小，則可減少被擴散圖案反射而從前面側的導光 板射出的光量，可降低點亮前面側光源時的發光亮度。 又，若使前面側的導光板之擴散圖案的圖案密度或表面 粗度變小，則可減少從背面側的導光板射出的光在穿透 前面側的導光板時的損失。其結果，可縮小點亮前面側 光源時的發光亮度與點亮背面側光源時之發光亮度的差 。然而’若考量點亮前面側光源時與點亮背面側光源時 之發光亮度比的最大値’則前述前面側的導光板之前述 擴散圖案的圖案密度或表面粗度，較佳為前述背面側的 導光板之前述擴散圖案的圖案密度或表面粗度的1/2以 上。 又，為 前述前面側 的導光板之 之發光區域 出的光在穿 而造成穿透 前面側的光 之發光區域 光區域的厚 本發明 的導光板之 發光區域的 的厚度變薄 透前面側的 損失，故可 源時的亮度 的厚度較佳 度的1/3倍。 面光源裝置 叫守 發光區 厚度即 ，則可 導光板 縮小點 差。其 為厚於 光板的穿透損失，只要使 域的厚度薄於前述背面側 可。若使前面側的導光板 減少從背面側的導光板射 時因產生的吸收、散射等 亮背面側的光源時與點亮 中，前述前面側的導光板 前述背面側的導光板之發 的另一實施態樣中，從前述背面 -10- 201235614 側的導光板的光射出面射出之光的指向性係窄於從前述 前面側的導光板的光射出面射出之光的指向性。若從背 面側的導光板的光射出面射出之光的指向性變窄，則點 亮背面側光源時的發光亮度會變高，所以能縮小點亮前 面側的光源時的發光亮度與點亮背面側的光源時的發光 亮度之差。 為了使背面側的導光板的指向性變窄，例如，較佳 為使複數個雙凸透鏡（lenticular lens)排列於前述前面側 的導光板和前述背面側的導光板各自的前面和背面中的 任一者’只要使前述背面側的導光板之前述雙凸透鏡的 邊緣角度大於前述前面側的導光板之前述雙凸透鏡的邊 緣角度即可。若使設置於背面側的導光板之雙凸透鏡的 邊緣角度變大，則能提高該雙凸透鏡的透鏡效果，所以 月&使從背面側射出之光的指向性變窄，能提高點亮背面 側的光源時的發光亮度。其中，前述背面側的導光板之 刖述雙凸透鏡的邊緣角度較佳為6 〇 〇以下。 本發明的立體顯示裝置，其特徵為，於本發明的面 光源裝置的前方’配置有光學片及液晶面板。本發明的 立體顯7F裝置中’由於是使用本發明的面光源裝置，所 以可使左眼所觀察的畫像和右眼所觀察的晝像的發光亮 度相等’能觀察取得左右平衡的立體影像。 另外’用以解決本發明的前述課題的手段，具有適 當組合有上述說明之構成要素的特徵，本發明可藉由此 構成要素的組合而產生多種變形。 【實施方式】 -11 - 201235614 [實施發明之形態] 以下’參照附圖’說明本發明之較佳實施形態。惟 ’本發明不限定於以下的實施形態，在不脫離本發明之 主旨的範圍内皆可進行各種設計變更。 [第1實施形態] 首先，參照圖2及圖3，說明本發明實施形態1之面光 源裝置3 1的構造。圖2為顯示實施形態！之面光源裝置3 j 的立體圖。圖3為面光源裝置31的示意剖面圖。 圖2及圖3所示的面光源裝置31中，以導光板32a為前 面側且導光板32b為背面側的方式重疊兩導光板32a、32b 而形成導光體32。導光板32a和導光板32b是由聚碳酸酯 樹脂、聚甲基丙烯酸甲酯樹脂等折射率高的透光性樹脂 成形為大致整體為均勻厚度的平板狀。又，於導光板32a 、32b的前面及背面中的至少一面，成形有呈凸狀或凹狀 之微小的多數擴散圖案37a、37b。 如圖3所示，導光板32a和等光板3215係設成其各自的 光射入端面33a、33b相互位於相反側，且以導光板32a 的背面和導光板32b的前面相向的方式重疊。其中，導光 板32a和導光板32b並未直接密接，而是挾著折射率比兩 導光板32a、32b還小的低折射率層36(例如空氣層、透明 黏着劑層、透明液體層等）而重疊。 於導光體32的背面配置有反射構件4(^反射構件4〇 係由白色樹脂片、金屬簿等反射率高的材料形成，用以 將自導光體32背面漏出的光加以反射並使其再射入導光 體32 ’以減少漏光而提高光利用效率。 -12- 201235614 在與導光板32a的光射入端面33a對向的位置，配置 有1個或複數個光源41a。同樣地，在與導光板32b的光射 入端面33b對向的位置，配置有1個或複數個光源。光 源4U及41b皆由LED光源所構成。亦即’如圖3所示，在 兩光源4U、41b中，LED晶片42被封裝於透明樹脂43内 ，透明樹脂43之正面（光射出窗）以外的各面係被白色樹 脂所構成的被覆部44覆蓋著。因此，使LED晶片42發光 時，光會從各光源41a、4lb的正面射出。此光源4U在撓 性印刷基板45a上安裝有1個或複數個，撓性印刷基板45a 可如圖3所示位於光源41a的前面側，亦可位於光源41a 的後面側。光源41b於另一撓性印刷基板4513上安裝有1 個或複數個’撓性印刷基板4 5 b亦如圖3所示般可位於光 源4 lb的後面側’亦可位於光源4 lb的前面側。另外，就 光源4 1 a及4 1而言，亦可使用冷陰極管來取代led光源。 其次’參照圖3 ’說明上述構造之面光源裝置3丨中之 光的行徑。光源41 a和光源41b係被控制成能以一定周期 父替地反覆點兜或媳滅。當光從前面側^光源4 1 a射出時 ，該光會從光射入端面33a射入導光板32a内，一面在導 光板32a的前面和背面反覆進行全反射，一面導光於導光 板32a内。然後’當於導光板323内進行導光之光被設置 於導光板3 2 a背面的擴散圖案3 7 a反射，而以比全反射的 臨界角還小的射入角朝導光板32a的前面射入時（或被設 置於導光板32a前面的擴散圖案37a擴散時），係如左側照 明光38a般從導光體32朝左斜前方射出。同樣地，從背面 側的光源4 1 b射出而於導光板3 2 b内進行導光的光被設置 -13- 201235614 於導光板3 2b背面的擴散圖案3 7b反射而以比全反射的臨 界角還小的射入角朝導光板32b的前面射入時（或被設置 於導光板32b前面的擴散圖案37b擴散時），係如右側照明 光38b般從導光板32b射出，進一步穿透導光板而從導 光體32朝右斜前方射出。如圖3所示，此等左側照明光38a 和右側照明光38b係相對於垂直於導光板32a前面的法線 方向朝相反側傾斜，而如後述般成為用以產生立體影像 之最佳光線。 此面光源裝置3 1中’背面側光源4丨b的亮度相對較前 面側光源4 1 a的亮度高。如此，若事先將光源4丨b的亮度 β又成南於光源41a的亮度，則點亮光源41b時之導光板32b 的光射出面的發光亮度會高於點亮光源41a時之導光板 3 2&的光射出面的發光亮度。因此，即便自導光板3 2b射 出之光源41b的光穿透導光板32a時被導光板32a吸收或 散射而產生損失’亦可縮小觀察者所感受到之左側照明 光38a和右側照明光38b的亮度差。 關於提高光源41b之亮度[cd/cm2 ]的方法，有例如： (1)增大通電至光源的電流値[mA]之方法、（2)提高光源的 光度[cd](或光束[lm])之方法、增加1個光源内的led( 晶片）數量之方法。 首先，說明使用相同光源來調整電流値的方法（1)。 例如’測定於前面側的光源4 1 a流通電流I a而僅點亮光源 41a時之面光源裝置31的發光亮度（導光板32&之光射出 面的發光亮度）。接著，以使僅點亮背面側的光源4丨b時 之面光源裝置31的發光亮度（自導光板3 2b的光射出面發 -14- 201235614 出而穿透導光板32a之光的發光亮度）與僅點亮光源41a 時之面光源裝置3 1的發光亮度大致相等的方式，調整流 通於光源4 1 b的電流。將此時之光源4 1 b的電流値設為Ib( > la)。依此方式’若使用面光源裝置3 1實驗性地求電流 値lb ’只要設成以電流値ia驅動光源4 1 a，以電流値11?驅 動光源4 1 b即可。 又’如圖4(A)所示’若由光源的目錄（特性表）、實 際測量等，得知光源的亮度與電流値的關係，便能決定 電流値為la時之光源41 a的亮度Ka與電流値為時之光 源41b的亮度Kb(或亮度比Kb/Ka)。 關於調整光度的方法（2)，只要將光源41a和光源41b 設成種類不同的光源’以僅點亮光源4 1 b時所觀察之面光 源裝置3 1的發光亮度與僅點亮光源4 1 a時的發光亮度大 致相等的方式來選擇各光源41a、41b即可。例如，如圖 4(B)所示，若得知光源的亮度與從光源發出之光的光束（ 或光度）的關係，便成決定從亮度K a求得作為光源4 1 a的 光束（或光度），且能決定從亮度Kb求得作為光源41b的光 束（或光度）。因此，只要根據光源的製品目錄等，依此 方式選擇具有所決定之光束（或光度）的値的光源4丨a、 41b即可。然而，由於自導光板32b的光射出面發出的光 穿透導光板32a所產生的損失，最大估計是三十幾％，因 此背面側光源41b的光度較佳為前面側光源41&的光度的 1 · 5倍以下。 又，關於使1光源内之LED的數量（晶片數）不同的方 法（3)，只要使用圖4(C)所示之LED的數量與亮度的關係 -15- 201235614 ，選擇滿足最接近所要求之亮度Ka、Kb(或亮度比）之LED 的數量之種類的光源作為各自的光源4 1 a、4 1 b即可。 此外’如圖5所示，亦可使與導光板32a的光射入端 面33a對向而配置之光源41a的數量、以及與導光板32b的 光射入端面33b對向而配置之光源4lb的數量不同以均等 地調整面光源裝置31的發光亮度。 圖6為顯示使用上述面光源裝置31之立體顯示裝置 51的構造。該立體顯示裝置51中，光學片53重疊於導光 體32的前面’邊緣片（rim sheet)52從該光學片53的前面黏 貼於面光源裝置3 1。邊緣片5 2係由黑色黏著帶等所形成 的光吸收用構件，其與導光體32之發光區域對應的區域 形成有開口，且覆蓋著導光體32的前面周圍。又，在邊 緣片5 2開口部的前方，重疊有液晶面板5 4。 光學片53的背面形成有排列著微細三角稜鏡的稜鏡 列53a，光學片53的前面則形成有排列著微細凸透鏡的圓 筒透鏡列53b。稜鏡列53a及圓筒透鏡列53b，其等與導光 板32a、32b之寬度方向（γ方向）垂直的剖面係呈均勻的剖 面形狀，且沿著導光板32a、32b的長度方向（χ方向）分別 以一定間距排列。其中，圓筒透鏡列53b的排列間距稍大 於稜鏡列53a的排列間距。稜鏡列53a係以相對於通過光 學片53中心之與X方向垂直的面成為對稱的方式配置，圓 筒透鏡列53b亦以相對於通過光學片53中心之與X方向垂 直的面成為對稱的方式配置。液晶面板5错藉由同㈣ 動裝置5 6控制成交替地顯示觀察者以右眼觀看時的畫像 (右眼用畫像）和以左目艮觀看時的畫像（左眼用纟像卜此外 •16- 201235614 ’圖7中’ Z方向表示導光板32a、32b的厚度方向。 液晶面板54的左眼用/右眼用畫像與光源41&及4卟 的點亮/熄滅係由同步驅動裝置56所同步控制。同步驅動 裝置56係以觀察者無法辨識左右晝像的切換之程度的短 周期交替地使液晶面板54顯示左眼用晝像和右眼用畫像 ，且與液晶面板54的左眼用晝像同步地而使光源4丨a點亮 (使光源41b熄滅），與右眼用畫像同步地而使光源41b點 免（使光源4 1 a媳滅）。 光源4 1 b點亮時，從光源4 1 b發出的光（白色光）係當 作最大強度方向一致的右側照明光38b而從導光體32的 發光區域整體朝右斜前方射出。從導光體32射出的右側 照明光38b中穿透各畫素的光藉光學片53彎折後，會射入 液晶面板54 ’以聚集在與液晶面板54相距大致既定距離 之觀察者的右眼55b。此右側照明光38b係藉由穿透液晶 面板54被轉換成右眼用晝像，而由觀察者的右眼5 5b所辨 識。 门樣地，光源4 1 a點亮時，從光源4 1 a發出的光（白色 光）係作為最大強度方向一致的左側照明光38a而從導光 體32的發光區域整體朝左斜前方射出。從導光體32射出 的左側照明光38a中穿透各晝素的光其方向藉光學片Η 考折後’會射入液晶面板54，以聚集在觀察者的左眼55a 。此左側照明光3 8a係藉由穿透液晶面板54被轉換成左眼 用晝像’而由觀察者的左眼55a所辨識。 此時’於藉由光學片5 3的作動使射入稜鏡列5 3 a的左 側Μ明光38a其光線方向藉稜鏡列53a彎折後，進一步穿 -17- 201235614 透圓筒透鏡列53b之際’光藉由圓筒透鏡列53b被彎折成 朝向左眼55a的方向而聚集在左眼55a。右側照明光38b係 以同樣的作動’穿透光學片53而聚集在右眼55b。 依此，左眼用晝像和右眼用晝像交替地被傳送至觀 察者的左眼55a和右眼55b ’而由於藉由殘影效果使得觀 察者可同時辨識右眼用晝像和左眼用晝像，所以能辨識 二維影像（立體影像）。此立體顯示裝置5 1中，由於是使 用面光源裝置3 1，故左眼用畫像和右眼用畫像感受到大 致相同的亮度，能辨識取得左右平衡之具立體感的立體 畫像。 [第2實施形態] 圖7係顯示本發明實施形態2之面光源裝置6丨的示意 剖面圖。使用於面光源裝置61的導光板32a、32b係如圖8 所不，由板厚較厚的光導入部62、成為發光區域之板厚 較薄的導光板本體63、和連結光導入部62和導光板本體 63之間的光移行部64(傾斜區域）所構成。導光板32&的前 面和導光板32b的背面成為平坦面65，與光導入部62的平 坦面65對向的面係成為與平坦面65大致平行的突平面66 ，與導光板本體63的平坦面65對向的面係成為與平坦面 65大致平行的本體平面67，與光移行部64的平坦面65對 向的面係成為從突平面66朝本體平面67傾斜的傾斜面68 三光導=部62的厚度係大於光源41a、41b之光射出窗的 问度且等於或小於光源41a、41b的高度。在導光板本體 6的f i一面65和本體平面67的任一面，形成有微細的多 數擴散圖案(例如，凹陷成剖面三角形的稜鏡狀圖案等係 -18- 201235614 排列成平行或圓弧狀），該微細的多數擴散圖案係用以使 光從導光板本體6 3朝前面側射出。 導光板3 2 a和導光板3 2 b係如圖7所示般設成以使導 光板32a上下翻轉’且光導入部62側彼此和導光板本體63 側彼此相互位於相反側的方式，隔著低折射率層使導光 板本體63的本體平面67彼此重疊。因此，導光板32a中導 光板本體63的平坦面65成為光射出面，導光板32b中導光 板本體63的本體平面67成為光射出面。又，無論是導光 板32a還是導光板32b，光導入部62的突出部分均朝向内 側而不會突出至導光體32的外面，所以可將面光源裝置 31薄型化。光源4la係與位於導光板32a之光導入部。側 的光射入端面33a對向而配置，光源41b係與位於導光板 32b之光導入部62側的光射入端面33b對向而配置。 此面光源裝置61中，由於光導入部62的厚度係與各 光源4 1 a ' 4 1 b的咼度大致相等，所以可將從各光源4 h 、41b發出的光高效率地射入導光板32&、3孔内而可提 高光的利用效率ϋ面，由於佔導光板％、咖之 大部分區域的導光板本體63的厚度變薄，所以可將重疊 導光板32a、32b彼此而成的導光體32 ’由於是將位於光導入部62和導光板本二:的= 仃部64的上面設為傾斜面68，所以可一面將射入光導入 部62的光在平坦面65和傾斜面“進行全反射一面抑制 漏光而高效率地將光引導至導光板本體63。 ’如圖7所示，位於背面 突平面66與導光板本體 另外’於此面光源裝置6丨中 側的導光板32b的光導入部62的 -19- 201235614 63的本體平面67之間的階差（即，傾斜面“所形成的階差 )Hb，係小於位於表面側之導光板32a的光導入部a的突 平面66與導光板本體63的本體平面67之間的階差（即，傾 斜面68所形成的階差）Hae又，導光板32a之導光板本體 63的厚度係薄於導光板32b之導光板本體63的厚度。圖9 為顯示實際測量圖8所示之形狀之導光板32a、3孔的階差 大小與因階差導致的損失之關係的結果之圖。如圖9所示 ，當階差變大時，傾斜面68的傾斜變陡，所以自光導入 邓62進入導光板32a、32b内的光容易從傾斜面μ漏出， 因此階差所導致的損失變大。 前面侧的導光板32a由於其階差Ha比較大，所以光的 損失大，點亮光源41a時從導光板32a射出之光的強度降 低的紅度嫒大。另一方面，背面側的導光板3 2b由於其階 差Hb比較小，所以損失少，點亮光源4 1 b(由於使用與光 源41a相同的構成）時從導光板32b的前面射出之光的強 度降低的程度較小。然而，從導光板32b的前面射出的光 ，其在穿透導光板32a時會因吸收或散射而產生損失，所 以，、要適當地選擇導光板323、3213之階差1^3、111)的差異 ,即可在自面光源裝置6丨的前面射出的階段，不論是僅 點亮光源41a時或僅點亮光源41b時都能調整成相同程度 的發光亮度。 · 然而’導光體32較佳為導光板32a之光導入部62的下 面（即犬平面66)與導光板32b的背面位在同一平面，且導 光板3 21>之光導入部62的前面（即突平面66)與導光板323 的对面位在同一平面。此時，導光板32&及32b之各光導 -20- 201235614 入部6 2的厚度择& κ丨# ’、 等於導光板32a之導光板本體63的 旱度及‘光板32b之導光板本體63的厚度之和，所以導光 體32的大致整體成為# 成為均勾厚度，因此可容易進行面光源 :置61的組裝、操作。再者，若導光體的厚度(即，導 光板32a之導光板本體63的厚度及導光板32b之導光板本 體63的厚度之和）與光源4U、川的高度相等，則面光源 裝置61的大致整體會成為均勻厚度。 ▲此種形態的面光源裝置61中’導光板32b的階差Hb 較佳為導光板32&的階差]^的1/4倍以上（即，Ha/4$Hb<201235614 VI. Description of the Invention: [Technical Field of the Invention] The present invention relates to a surface light source device and a stereoscopic display device. Specifically, the present invention relates to a stereoscopic display device for three-dimensionally displaying an image or an image, and a surface light source device for use in the stereoscopic display device. [Prior Art] A stereoscopic display device for displaying a so-called three-dimensional image has a method of using observation glasses and a method of not using glasses. However, in the method of using glasses, since the observer must wear the glasses on the head, it is not only annoying but also gives the observer an uncomfortable feeling. Therefore, it is preferable to use a method of not using glasses as the stereoscopic display device. As a stereoscopic display device that does not use glasses, for example, those disclosed in Patent Document 1 or disclosed in Patent Document 2 are disclosed. Fig. 1(A) shows a stereoscopic display device 1 1 disclosed in Patent Document 1. In the stereoscopic display device 11, a light guide plate 12 is formed by overlapping a wedge-shaped light guide plate 12a and a wedge-shaped light guide plate 12b. The light guide plate i2a and the light guide plate 12b are overlapped with each other via the air layer such that the light guide plate i2a is on the front side and the light guide plate 12b is on the back side. The end face on the thicker side of the light guide plate 12a is aligned with the left and right positions of the end face on the thinner side of the light guide plate 12b, and the end face of the light guide plate 12a having a thinner side and the thickness of the light guide plate 12b are thicker. The left and right positions of the end faces are aligned. The left side light source 1 3 a is opposed to the thick end surface of the light guide plate 12a. The right side light source Ub is opposed to the thick end surface of the light guide plate 12b. Further, a liquid crystal panel 15 is disposed on the front surface of the wafer i 4 with the cymbal sheet 14' disposed on the front surface of the light guide body. In addition, the liquid crystal panel 15 displays the image for the right eye and the image for the left eye alternately in a time-sharing manner, and the light source i 3a on the left side emits light in synchronization with the image for the left eye (in this case, the right light source 1 3 b is turned off). The right side light source 1 3 b is illuminated in synchronization with the right eye image (at this time, the left side light source l3a is turned off). As a result, in the stereoscopic display device 11, the left illumination light 16a emitted from the left side light source i3a is converted into the left eye image and enters the observer's left eyelid 7 & the right side light source 13b Shoot the right side of the lighting! 6b is converted into a right-eye image and incident on the observer's right eye 17b, and the observer recognizes the stereoscopic image. At this time, as shown in FIG. 1(B), the left illumination light 1 emitted from the left light source 1 3 a 6a is reflected on the back surface of the light guide plate 12a disposed on the front side, and then passes through the light guide plate 12a and is emitted forward from the light exit surface; the right side illumination light 16b emitted from the right side light source 13b is disposed in The back surface of the light guide plate 12b on the back side is reflected, and then sequentially passes through the light guide plates m and 12a to be emitted toward the front. On the other hand, the direction in which the light guide plate 12a and the light guide plate 12b are disposed is different from that of the front and rear of the arrangement, and the same material is used and the same material. Therefore, when the right illumination light i6b emitted from the light guide plate 12b on the back side penetrates the light guide plate 1 2 a on the side of the pupil surface, it absorbs and scatters excessively compared to the left illumination light 6 a. As a result, when the observer views, the brightness of the right illumination light 16b emitted from the light guide plate 12b on the back side is lower than the brightness of the left illumination light 16a emitted from the front side light guide plate 12a, and the right eye is recognized. The portrait is inconsistent with the unevenness of the image recognized by the left eye. Since the surface light source device for stereoscopic display disclosed in Patent Document 2 has the same structure as that of the patent document, the brightness of the light emitted from the backlight of the 201235614 light guide plate is higher than that of the light emitted from the light guide plate on the front side. The brightness is lower, and the observer will feel the uneven brightness of the left and right portraits. [PRIOR ART DOCUMENT] [Patent Document 1] Japanese Patent Laid-Open Publication No. Hei. No. Hei. No. Hei. No. 2008-287180. In view of the above-described technical problems, the developer has an object of illuminating the luminance of the light emitted from the light guide plate located on the back side of the surface light source device in which the two light guide plates are stacked, and from the surface side. The brightness of the light emitted by the light guide plate allows the viewer to feel more uniform when viewing. [Means for Solving the Problem] The surface light source device of the present invention includes a pair of light guide plates that overlap each other in such a manner that the surface faces the back surface, and the light source on the front side is an end surface of the light guide plate located on the other surface side. The light source on the back side is disposed facing the one end of the light guide plate on the back side; and is characterized in that: only the light source on the front side is illuminated to light from the front side The illuminance observed when the light exit surface of the light plate is emitted, and the light illuminating through the light guide plate on the front side when the light source on the moon surface side is illuminated to emit light from the light exit surface of the light guide plate on the back surface side The brightness becomes the same brightness. It is configured to illuminate only the 201235614 light source in the surface light source device of the present invention on the front side so that the light is emitted from the light-emitting luminance and the light-emitting luminance of only the light-emitting surface of the light guide plate is used for the eye and enters the right eye. The stereoscopic image showing the right balance of the stereoscopic image is lighter when the light source on the back side of the surface light of the present invention is higher than the light emitted from the light guide plate on the back side of the light guide plate on the other side. The light emitted from the light source on the front side is brighter than the light source on the light side of the present invention, since only the light-emitting luminance on the back side is illuminated. Therefore, when the light guide plate on the front side of the light guide plate is used to supplement the light source and the light source on the back side of the light guide plate on the front side of the rear side is illuminated, the light is emitted through the front side, so that the intensity of the light can be reduced. . Therefore, in a certain embodiment of the image display device, the light guide light on the back surface side illuminates the light emission luminance on the front surface side. When the emitted light increases the light source of the light guide on the back side before the penetration, the difference in luminance of the light-emitting luminance is small. The other implementation of the source device is higher than that of the front side of the light source of the back side. The loss of the light guide plate on the side can be compensated, and only when the light-emitting surface of the light source on the front side is emitted, the light is emitted from the light guide plate on the back side to the left of the observer. In the case of the surface light source device, it is possible to observe the above-mentioned front surface when the light source of the light exit surface of the above-mentioned panel is only obtained in the left sample, and according to this embodiment, the light-emitting luminance of the panel on the surface side is complemented and only Lights up the brightness of the back side light source in the back side 0 aspect. According to the brightness, the difference in luminance of the light-emitting luminance when the light emitted from the light-emitting surface of the light-emitting plate is increased by the light source on the back side before the penetration is increased, in order to increase the brightness of the light source on the back side. The illuminance of the light source on the front side of the back surface 201235614 is larger than the illuminance of the light source on the front side, that is, the maximum loss when the light guide plate penetrates the front side is considered to be the light source of the front side. 1.5 times or less. In another embodiment of the surface light source device of the present invention, the light guiding efficiency of the back light guide plate is higher than that of the light guide plate on the front side. According to this aspect, the loss of light from the light guide plate on the back side when passing through the light guide plate on the front side can be compensated by the emission efficiency of the light guide plate on the back side, and can be reduced only when the front light source is turned on. The luminance of the light is different from the luminance of the luminance when only the light source on the back side is lit. In order to improve the light-emitting efficiency of the light guide plate on the back side, it is preferable that the light guide plate on the front side and the light guide plate on the back side are light guide plate bodies having a small thickness in the light-emitting region, and at least a part of the light-introducing portion has a thickness larger than the thickness of the light guide plate, and the light source on the front side or the back side is disposed on the end surface; and the light transfer portion changes the thickness of the light guide plate body and the light introduction manner; the light guide plate on the back side The thickness difference between the light guide portion and the front side is smaller than the difference between the fourth portion of the light guide plate on the front side and the light guide plate body. The difference in thickness between the light introducing portion of the light guide plate and the light guiding portion main body is two: it is easy to change from the thickness between the light introducing portion and the light guiding portion main body. Therefore, if the thickness of the light guide plate on the back side is 〇, the smooth surface The side light is emitted to the side of the light-emitting side. For example, the body is introduced into the light-transmitting plate, and the light portion is reduced to 201235614. The light leakage of the light guide plate on the back side is smaller than that of the light guide plate on the front side, and the back side is The light-emitting plate has a higher emission efficiency. As a result, the difference between the light-emitting luminance when the light source on the front side is illuminated and the light-emitting luminance when the light source on the back side is illuminated can be reduced. Further, in this embodiment, it is preferable that a thickness of each of the light introducing portions of the front side light guide plate and the back side light guide plate is a thickness of the light guide plate body of the front side light guide plate and the back surface The sum of the thicknesses of the light guide body of the side light guide plate is equal. According to this aspect, since the overall thickness of the surface light source device is substantially uniform, it is easy to assemble into a backlight, and the optical sheet and the liquid crystal panel can be stabilized, and productivity is also improved. Further, the light introducing portion of the light guide plate on the back surface side protrudes forward from the front surface of the light guide plate main body, and the light introducing portion of the front side light guide plate protrudes rearward from the rear surface of the light guide plate main body In a case where the thickness difference between the light introducing portion of the light guide plate on the back surface side and the light guide plate main body is 1/4 times the difference in thickness between the light introducing portion and the light guide plate body of the light guide plate on the front side the above. In another embodiment of the surface light source device of the present invention, the penetration loss of the light guide plate on the front side is smaller than the penetration loss of the light guide plate on the back side. According to this embodiment, the penetration of the light guide plate on the front side is Since the loss becomes small, the loss of light emitted from the light guide plate on the back side when passing through the light guide plate on the front side can be reduced, and the light-emitting 7C degree when only the light source on the front side is illuminated and the light source on the back side only can be reduced. In order to reduce the penetration loss of the light guide plate on the front side, for example, any one of the front and back sides of the light guide plate on the front side and the light guide on the back side may be used. The diffusion pattern is formed such that the pattern density or the surface roughness of the diffusion pattern of the light guide plate on the front side is smaller than the pattern density or the surface roughness of the diffusion pattern of the light guide plate on the back surface side. When the pattern density or the surface roughness of the diffusion pattern of the light guide plate on the surface side is reduced, the amount of light that is reflected by the diffusion pattern and emitted from the light guide plate on the front side can be reduced, and the luminance of the light when the front side light source is turned on can be reduced. . Further, when the pattern density or the surface roughness of the diffusion pattern of the light guide plate on the front side is made small, the loss of light emitted from the light guide plate on the back side when passing through the light guide plate on the front side can be reduced. As a result, the difference between the light-emitting luminance when the front side light source is turned on and the light-emitting luminance when the back side light source is turned on can be reduced. However, it is preferable that the pattern density or the surface roughness of the diffusion pattern of the light guide plate on the front side is preferably the back side when considering the maximum 値 of the ratio of the luminance of the light when the front side light source is turned on and the light source for the rear side light source. The pattern density of the diffusion pattern of the light guide plate or the surface roughness is 1/2 or more. Further, the light emitted from the light-emitting region of the light guide plate on the front side is thicker than the light-emitting region of the light that penetrates the front side, and the thickness of the light-emitting region of the light guide plate of the present invention is thinned toward the front side. Loss, so the thickness of the brightness at the time of source can be 1/3 times better. The surface light source device is called the light-emitting area, that is, the thickness of the light guide plate can be reduced. It is a penetration loss thicker than the light plate as long as the thickness of the domain is thinner than the aforementioned back side. When the light guide plate on the front side is used to reduce the light source on the back side due to absorption or scattering caused by the light guide plate on the back side, the light guide plate on the front side of the light guide plate on the front side is additionally In one embodiment, the directivity of the light emitted from the light exit surface of the light guide plate on the side of the back surface -10- 201235614 is narrower than the directivity of the light emitted from the light exit surface of the light guide plate on the front side. When the directivity of the light emitted from the light exit surface of the light guide plate on the back side is narrowed, the light emission luminance when the back side light source is turned on is increased, so that the light emission luminance and the lighting when the light source on the front side is lighted can be reduced. The difference in luminance between the light sources on the back side. In order to narrow the directivity of the light guide plate on the back side, for example, it is preferable that a plurality of lenticular lenses are arranged on the front surface and the back surface of each of the light guide plate on the front surface side and the light guide plate on the back surface side. In one case, the edge angle of the lenticular lens of the light guide plate on the back side may be larger than the edge angle of the lenticular lens of the light guide plate on the front side. When the edge angle of the lenticular lens of the light guide plate provided on the back side is increased, the lens effect of the lenticular lens can be improved, so that the directivity of the light emitted from the back side is narrowed, and the back surface can be improved. Luminance of the light source on the side. The angle of the edge of the lenticular lens of the light guide plate on the back side is preferably 6 〇 or less. The stereoscopic display device of the present invention is characterized in that an optical sheet and a liquid crystal panel are disposed in front of the surface light source device of the present invention. In the stereoscopic 7F device of the present invention, since the surface light source device of the present invention is used, it is possible to make the stereoscopic image in which the right and left balance is obtained by making the image observed by the left eye and the illuminance of the pupil observed by the right eye equal. Further, the means for solving the above-described problems of the present invention has the features in which the above-described constituent elements are appropriately combined, and the present invention can be variously modified by the combination of the constituent elements. [Embodiment] -11 - 201235614 [Embodiment of the Invention] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the embodiments described below, and various modifications can be made without departing from the spirit and scope of the invention. [First Embodiment] First, a structure of a surface light source device 3 1 according to a first embodiment of the present invention will be described with reference to Figs. 2 and 3 . Figure 2 shows the embodiment! A perspective view of the surface light source device 3 j . 3 is a schematic cross-sectional view of the surface light source device 31. In the surface light source device 31 shown in Fig. 2 and Fig. 3, the light guides 32 are formed by overlapping the two light guide plates 32a and 32b so that the light guide plate 32a is on the front side and the light guide plate 32b is on the back side. The light guide plate 32a and the light guide plate 32b are formed of a light-transmissive resin having a high refractive index such as a polycarbonate resin or a polymethyl methacrylate resin, and are formed into a substantially flat plate shape having a uniform thickness. Further, on at least one of the front surface and the back surface of the light guide plates 32a and 32b, a plurality of minute diffusion patterns 37a and 37b which are minute in a convex shape or a concave shape are formed. As shown in Fig. 3, the light guide plate 32a and the iso-optical plate 3215 are disposed such that their respective light incident end faces 33a and 33b are located on opposite sides of each other, and the back surface of the light guide plate 32a and the front surface of the light guide plate 32b are opposed to each other. The light guide plate 32a and the light guide plate 32b are not directly in close contact with each other, but a low refractive index layer 36 (for example, an air layer, a transparent adhesive layer, a transparent liquid layer, etc.) having a smaller refractive index than the two light guide plates 32a and 32b. And overlap. The reflection member 4 is disposed on the back surface of the light guide body 32. The reflection member 4 is formed of a material having a high reflectance such as a white resin sheet or a metal sheet, and reflects light leaking from the back surface of the light guide 32. The light guide 32' is incident on the light guide 32' to reduce the light leakage to improve the light use efficiency. -12- 201235614 One or a plurality of light sources 41a are disposed at positions facing the light incident end surface 33a of the light guide plate 32a. One or a plurality of light sources are disposed at a position opposed to the light incident end surface 33b of the light guide plate 32b. The light sources 4U and 41b are each composed of an LED light source. That is, as shown in Fig. 3, at two light sources 4U In the 41b, the LED chip 42 is encapsulated in the transparent resin 43, and the surface other than the front surface (light emitting window) of the transparent resin 43 is covered with the covering portion 44 made of white resin. Therefore, when the LED chip 42 is illuminated The light is emitted from the front surface of each of the light sources 41a and 4b. One or a plurality of the light sources 4U are mounted on the flexible printed circuit board 45a, and the flexible printed circuit board 45a is located on the front side of the light source 41a as shown in FIG. It can be located on the back side of the light source 41a. The light source 41b is on the other side. One or a plurality of 'flexible printed boards 4 5 b on the printed substrate 4513 may be located on the rear side of the light source 4 lb as shown in FIG. 3 ' may also be located on the front side of the light source 4 lb. In addition, the light source 4 In the case of 1 a and 4 1 , a cold cathode tube may be used instead of the led light source. Next, the path of the light in the surface light source device 3 of the above configuration will be described with reference to Fig. 3 '. The light source 41 a and the light source 41 b are controlled to The light can be reversed or annihilated by a certain period of time. When light is emitted from the front side light source 4 1 a, the light is incident into the light guide plate 32a from the light incident end face 33a, and the light is incident on the front side of the light guide plate 32a. And the back surface is totally reflected and the light is guided in the light guide plate 32a. Then, when the light guided in the light guide plate 323 is reflected by the diffusion pattern 3 7 a disposed on the back surface of the light guide plate 3 2 a, When the incident angle of the reflection is small, the incident angle is incident toward the front surface of the light guide plate 32a (or when the diffusion pattern 37a is disposed in front of the light guide plate 32a), and is leftward from the light guide 32 as the left illumination light 38a. Shooting obliquely forward. Similarly, the light source 4 1 b from the back side is emitted and guided The light guided in the plate 3 2 b is set to be reflected by the diffusion pattern 37b on the back surface of the light guide plate 3 2b from 13 to 201235614, and is incident on the front surface of the light guide plate 32b at an incident angle smaller than the critical angle of total reflection. The time (or when the diffusion pattern 37b provided on the front surface of the light guide plate 32b is diffused) is emitted from the light guide plate 32b like the right illumination light 38b, and further penetrates the light guide plate to be emitted obliquely forward from the light guide body 32 to the right. As shown in Fig. 3, the left illumination light 38a and the right illumination light 38b are inclined toward the opposite side with respect to the normal direction perpendicular to the front surface of the light guide plate 32a, and are optimal light for generating a stereoscopic image as will be described later. In the surface light source device 3 1 , the luminance of the back side light source 4 丨 b is higher than the brightness of the front side light source 4 1 a. In this manner, if the brightness β of the light source 4丨b is made souther than the brightness of the light source 41a, the light-emitting surface of the light-emitting surface 32b when the light source 41b is turned on is higher than the light-guide plate 3 when the light source 41a is turned on. The brightness of the light exiting the surface of 2& Therefore, even if the light from the light source 41b emitted from the light guide plate 32b passes through the light guide plate 32a, it is absorbed or scattered by the light guide plate 32a to cause a loss, and the brightness of the left illumination light 38a and the right illumination light 38b perceived by the observer can be reduced. difference. Regarding the method of increasing the luminance [cd/cm2 ] of the light source 41b, for example, (1) increasing the current 値 [mA] applied to the light source, and (2) increasing the luminosity [cd] of the light source (or the beam [lm] The method of adding a number of leds (wafers) in one light source. First, a method (1) of adjusting the current 使用 using the same light source will be described. For example, the light-emitting luminance of the surface light source device 31 (the light-emitting luminance of the light-emitting surface of the light guide plate 32 & light source) when the light source 41 a on the front side flows and the light source 41 a flows only. Then, the light-emitting luminance of the surface light source device 31 when the light source 4b on the back side is illuminated only (the light-emitting luminance of the light that has passed through the light guide plate 32a from the light exit surface of the light guide plate 32b) The current flowing through the light source 4 1 b is adjusted so as to be substantially equal to the light-emitting luminance of the surface light source device 3 1 when only the light source 41a is turned on. The current 値 of the light source 4 1 b at this time is set to Ib ( > la). In this manner, if the surface light source device 3 1 is used to experimentally calculate the current 値 lb ', the light source 4 1 a is driven by the current 値 ia, and the light source 4 1 b is driven by the current 値 11 。. Further, as shown in Fig. 4(A), if the relationship between the brightness of the light source and the current 得知 is obtained from the catalogue (characteristic table) of the light source, actual measurement, etc., the brightness of the light source 41a when the current 値 is la can be determined. Ka is the luminance Kb (or luminance ratio Kb/Ka) of the light source 41b when the current is 値. Regarding the method (2) of adjusting the illuminance, the light source 41a and the light source 41b are provided as light sources of different types to illuminate the light source brightness of the surface light source device 3 1 and only the light source 4 1 when only the light source 4 1 b is illuminated. The light sources 41a and 41b may be selected in such a manner that the light-emitting luminances at a are substantially equal. For example, as shown in FIG. 4(B), if the relationship between the brightness of the light source and the light beam (or luminosity) of the light emitted from the light source is known, it is determined that the light beam as the light source 4 1 a is obtained from the luminance K a (or The illuminance) can be determined from the luminance Kb to obtain a light beam (or luminosity) as the light source 41b. Therefore, it is only necessary to select the light sources 4a, 41b having the determined light beam (or luminosity) in accordance with the product catalog of the light source or the like. However, since the loss of light emitted from the light exit surface of the light guide plate 32b through the light guide plate 32a is estimated to be 30%, the illuminance of the back side light source 41b is preferably the luminosity of the front side light source 41& 1 · 5 times or less. Further, regarding the method (3) of making the number of LEDs (the number of wafers) in one light source different, the relationship between the number of LEDs shown in FIG. 4(C) and the brightness is -15-201235614, and the selection is made to satisfy the closest requirement. The light source of the type of the number of LEDs of the luminance Ka, Kb (or luminance ratio) may be the respective light sources 4 1 a, 4 1 b. Further, as shown in FIG. 5, the number of the light sources 41a disposed opposite to the light incident end surface 33a of the light guide plate 32a and the light source 41b disposed to face the light incident end surface 33b of the light guide plate 32b may be used. The number is different to uniformly adjust the light emission luminance of the surface light source device 31. Fig. 6 is a view showing the configuration of a stereoscopic display device 51 using the above-described surface light source device 31. In the stereoscopic display device 51, the optical sheet 53 is superposed on the front surface of the light guide body 32. A rim sheet 52 is adhered to the surface light source device 31 from the front surface of the optical sheet 53. The edge sheet 52 is a light absorbing member formed of a black adhesive tape or the like, and an opening corresponding to a light-emitting region of the light guide 32 is formed to cover the periphery of the front surface of the light guide 32. Further, a liquid crystal panel 54 is superposed on the front side of the opening of the edge piece 52. On the back surface of the optical sheet 53, a matrix 53a in which fine triangular ridges are arranged is formed, and on the front surface of the optical sheet 53, a cylindrical lens array 53b in which fine convex lenses are arranged is formed. The cross-section 53a and the cylindrical lens row 53b have a uniform cross-sectional shape perpendicular to the width direction (γ direction) of the light guide plates 32a and 32b, and along the longitudinal direction of the light guide plates 32a and 32b (χ direction) ) are arranged at a certain interval. Among them, the arrangement pitch of the cylindrical lens rows 53b is slightly larger than the arrangement pitch of the matrix columns 53a. The array 53a is disposed symmetrically with respect to a plane perpendicular to the X direction passing through the center of the optical sheet 53, and the cylindrical lens array 53b is also symmetrical with respect to a plane perpendicular to the X direction passing through the center of the optical sheet 53. Mode configuration. The liquid crystal panel 5 is controlled by the same (4) moving device 56 to alternately display an image when the observer views with the right eye (the image for the right eye) and the image when viewed with the left eye (the left eye is used for the image). - 201235614 'The direction of Z in 'Fig. 7' indicates the thickness direction of the light guide plates 32a and 32b. The left eye/right eye image of the liquid crystal panel 54 and the light source/lighting/lighting of the light sources 41& and 4 are driven by the synchronous driving device 56. The synchronous drive device 56 alternately causes the liquid crystal panel 54 to display the left-eye image and the right-eye image in a short period in which the viewer cannot recognize the degree of switching of the right and left images, and the left eye of the liquid crystal panel 54 is used. The light source 4丨a is turned on in synchronization with the image (the light source 41b is turned off), and the light source 41b is clicked in synchronization with the image for the right eye (the light source 4 1 a is extinguished). When the light source 4 1 b is turned on, The light (white light) emitted from the light source 4 1 b is emitted as the right side illumination light 38b having the largest intensity direction, and is emitted obliquely forward from the entire light-emitting region of the light guide body 32. The right side illumination light emitted from the light guide body 32 is emitted. After the light penetrating each pixel in 38b is bent by the optical sheet 53, The liquid crystal panel 54' is incident on the right eye 55b of the observer gathered at a predetermined distance from the liquid crystal panel 54. The right illumination light 38b is converted into a right-eye image by penetrating the liquid crystal panel 54, and is observed by The right eye 5 5b is recognized by the right eye. When the light source 4 1 a is turned on, the light (white light) emitted from the light source 4 1 a is emitted from the light guide body 32 as the left side illumination light 38a having the largest intensity direction. The light-emitting area is entirely obliquely forward toward the left. The light that penetrates each element in the left-side illumination light 38a emitted from the light guide body 32 is incident on the liquid crystal panel 54 by the optical sheet, and is collected in the observation. The left eye 55a of the left side is identifiable by the viewer's left eye 55a by being transmissive to the left eye 昼 image by penetrating the liquid crystal panel 54. At this time, 'by the optical sheet 5 3 The action is such that the left side of the light beam 38a of the array 5 3 a is bent by the column 53a, and further penetrates the -17-201235614 through the cylindrical lens column 53b. 53b is bent to face the left eye 55a and gathers in the left eye 55a. Right side illumination light 38b By the same action, the optical sheet 53 is penetrated and gathered in the right eye 55b. Accordingly, the left eye and the right eye are alternately transmitted to the observer's left eye 55a and right eye 55b' due to The image sticking effect allows the observer to recognize the right eye image and the left eye image at the same time, so that the two-dimensional image (stereoscopic image) can be recognized. In the stereoscopic display device 51, the surface light source device 3 1 is used. Therefore, the left-eye image and the right-eye image have substantially the same brightness, and the three-dimensional image having the three-dimensional effect of the right and left balance can be recognized. [Second Embodiment] Fig. 7 shows a surface light source device according to the second embodiment of the present invention. A schematic cross-sectional view of 6丨. The light guide plates 32a and 32b used in the surface light source device 61 are as shown in Fig. 8. The light introduction portion 62 having a thick plate thickness, the light guide plate main body 63 having a thin thickness as a light-emitting region, and the connection light introduction portion 62 are provided. The light transition portion 64 (inclined region) between the light guide plate body 63 and the light guide plate body 63 is formed. The front surface of the light guide plate 32& and the back surface of the light guide plate 32b are flat surfaces 65, and the surface facing the flat surface 65 of the light introduction portion 62 is a projection plane 66 substantially parallel to the flat surface 65, and is flat with the light guide plate main body 63. The surface facing the surface 65 is a body plane 67 substantially parallel to the flat surface 65, and the surface facing the flat surface 65 of the light transition portion 64 is an inclined surface 68 inclined from the projection plane 66 toward the body plane 67. The thickness of the portion 62 is greater than the light-emitting window of the light sources 41a, 41b and is equal to or smaller than the height of the light sources 41a, 41b. On either side of the fi side 65 and the body plane 67 of the light guide plate main body 6, a fine plurality of diffusion patterns are formed (for example, a 稜鏡-shaped pattern recessed into a triangular cross section, etc., arranged in a parallel or arc shape) -18-201235614) The fine majority of the diffusion pattern is for emitting light from the light guide plate main body 63 toward the front side. The light guide plate 3 2 a and the light guide plate 3 2 b are arranged such that the light guide plate 32a is turned upside down as shown in FIG. 7 and the light introduction portion 62 side and the light guide plate main 63 side are located on opposite sides of each other, respectively. The low refractive index layer overlaps the body planes 67 of the light guide plate body 63 with each other. Therefore, the flat surface 65 of the light guide plate main body 63 in the light guide plate 32a serves as a light exit surface, and the main body plane 67 of the light guide plate main body 63 in the light guide plate 32b serves as a light exit surface. Further, regardless of the light guide plate 32a or the light guide plate 32b, the protruding portions of the light introducing portion 62 are directed toward the inner side without protruding to the outer surface of the light guide body 32, so that the surface light source device 31 can be made thinner. The light source 41a is connected to the light introducing portion of the light guide plate 32a. The light incident end surface 33a is disposed to face each other, and the light source 41b is disposed to face the light incident end surface 33b on the light introducing portion 62 side of the light guide plate 32b. In the surface light source device 61, since the thickness of the light introducing portion 62 is substantially equal to the thickness of each of the light sources 4 1 a ' 4 1 b, the light emitted from the respective light sources 4 h and 41 b can be efficiently incident on the light guide unit 62. In the light plate 32& and the three holes, the light utilization efficiency can be improved, and since the thickness of the light guide plate main body 63 in the majority of the light guide plate and the coffee cup is reduced, the overlapping light guide plates 32a and 32b can be formed. Since the light guide body 32' is provided on the upper surface of the light introduction portion 62 and the light guide plate 2 as the inclined surface 68, the light incident on the light introduction portion 62 can be on the flat surface 65 and The inclined surface "high-efficiency is used to suppress light leakage while guiding light to the light guide plate main body 63. As shown in Fig. 7, the rear projection plane 66 and the light guide plate body are additionally disposed on the middle side of the light source device 6A. The step difference between the body planes 67 of -19-201235614 63 of the light introducing portion 62 of the light guide plate 32b (that is, the step formed by the inclined surface) Hb is smaller than the light introducing portion of the light guide plate 32a on the surface side. The step difference between the projection plane 66 of a and the body plane 67 of the light guide plate body 63 ( , The stepped inclined surface 68 is formed) and Hae light guide plate main body 32a of the light guide plate is thinner than the thickness of the light guide plate line 32b of the light guide plate 63 of the thickness of the body 63. Fig. 9 is a view showing the result of actually measuring the relationship between the step size of the light guide plates 32a and 3 of the shape shown in Fig. 8 and the loss due to the step difference. As shown in FIG. 9, when the step becomes large, the inclination of the inclined surface 68 becomes steep, so that light entering the light guide plates 32a and 32b from the light introduction Deng 62 easily leaks from the inclined surface μ, and thus the loss due to the step difference is caused. Become bigger. Since the light guide plate 32a on the front side has a relatively large step Ha, the light loss is large, and the intensity of the light emitted from the light guide plate 32a when the light source 41a is turned on is reduced. On the other hand, since the light guide plate 32b on the back side has a small step Hb, the loss is small, and the light source 4 1b (the same configuration as the light source 41a) emits light from the front surface of the light guide plate 32b. The degree of strength reduction is small. However, the light emitted from the front surface of the light guide plate 32b is lost due to absorption or scattering when passing through the light guide plate 32a. Therefore, the step difference of the light guide plates 323 and 3213 is appropriately selected 1^3, 111) The difference can be adjusted to the same level of light emission when the light source 41a is turned on only when the light source 41a is turned on or only when the light source 41b is lighted. However, the light guide body 32 is preferably such that the lower surface of the light introducing portion 62 of the light guide plate 32a (i.e., the dog plane 66) is positioned on the same plane as the back surface of the light guide plate 32b, and the front surface of the light introducing portion 62 of the light guide plate 3 21 > (ie, the protrusion plane 66) is in the same plane as the opposite side of the light guide plate 323. At this time, the thickness of each light guide -20-201235614 of the light guide plates 32& and 32b is selected to be & κ 丨 # ', equal to the dryness of the light guide plate body 63 of the light guide plate 32a, and the light guide plate body 63 of the light plate 32b. Since the thickness of the light guide body 32 is substantially equal to the thickness of the light guide body 32, assembly and operation of the surface light source: 61 can be easily performed. Further, if the thickness of the light guide body (that is, the sum of the thickness of the light guide plate main body 63 of the light guide plate 32a and the thickness of the light guide plate main body 63 of the light guide plate 32b) is equal to the height of the light source 4U and the river, the surface light source device 61 is used. The approximate overall shape will become a uniform thickness. ▲ In the surface light source device 61 of this type, the step Hb of the light guide plate 32b is preferably 1/4 times or more of the step of the light guide plate 32& (i.e., Ha/4$Hb<;

Ha)。其理由如下：目前，因為不可能製作厚度為匪 以下的導光板，所以在如本實施形態之形狀的導光板中 ，導光板本體63可製成的最小厚度為約〇 lmm。又，目 前，由於一般所使用之光源41a、41b的高度為〇 5mm， 所以在使導光體32的厚度與光源41a、41b的高度一致的 情況下，另一導光板本體63的厚度成為〇 4mm以下。因 此，此種形態中，導光板32b的階差Hb(=導光板32a之導 光板本體63的厚度）成為導光板32a的階差Ha( =導光板 32b之導光板本體63的厚度）的ι/4倍以上。 不過’即便將背面側的導光板32b的階差Hb設成最小 (0.1mm) ’仍不足以使導光板32a和導光板32b的亮度相等 ’所以只要不拘泥於使面光源裝置6 1的整體厚度均勻的 點’亦可藉由將導光板32b的階差Hb設定為比導光板32a 的階差Ha的1/4倍更小的適當値’來縮小導光板32a、32b 彼此的亮度差。 此外’在光導入部從導光板本體的前面及背面等兩 -21 · 201235614 面突出的情況’只要將背面侧的導光板3 2b的光導入部62 與導光板本體6 3之厚度的差設成小於前面側的導光板 32a的光導入部62與導光板本體63之厚度的差即可。 [第2實施形態的變形例] 圖1 0(A)為顯示實施形態2之變形例的示意剖面圖。 此面光源裝置71中，導光板32a及32b之光導入部62各自 的高度、和重疊之導光板32a及3 2b之各導光板本體63的 合計厚度、和光源41a、41b各自的高度係彼此大致相等 。此面光源裝置7 1中，由於整體的厚度大致均勻，所以 容易組裝為背光源’能使光學片、液晶面板穩定，且亦 提升生産性。 圖10(B)為顯示實施形態2之其他變形例的示意剖面 圖。如此面光源裝置72所示，若導光板32b之光導入部62 與導光板本體63之間的階差Hb小於導光板32a之光導入 部62與導光板本體63之間的階差Ha，則導光板32b之導光 板本體63的厚度與導光板32a之導光板本體63的厚度亦 可相同。 圖1 1為顯示使用於實施形態2之面光源裝置6丨的導 光板32 a(或導光板3 2b)的其他例之立體圖。又，圖丨}中 一併顯示V槽69的剖面。圖13的導光板32a(或導光板32b) 中，沿著光移行部64的傾斜面6 8，相互平行且連續地排 列有多個微細之v槽。在使用此種導光板32a、32b之情況 ’可藉由V槽69使從光導入部62側射入傾斜面68的光返回 反射’所以可減少在將射入光導入部62的光朝導光板本 體63導光之途中從傾斜面68漏出的光，從而可提高光之 -22- 201235614 利用效率。藉此，可提高面光源裝置6丨之亮度。 圖1 2為顯示使用於實施形態2之面光源裝置6丨的導 光板32 a(或導光板3 2b)的另一例之立體圖。在圖12之導 光板32a(或導光板32b)中’於各光源4la(或光源41b)之前 方’於光移行部64之傾斜面68形成有呈大致扇形的圖案 區域70。於各圖案區域70中’多數微細的v槽69係形成放 射狀。當從垂直於本體平面67之方向觀察時，各光源41a( 或光源41b)前方之V槽69係以各光源41a(或光源41b)之 發光點或其附近的點為中心而形成為放射狀。在使用圖 12所示之導光板32a、32b的情況下，亦可藉由v槽69使從 光射入端面33a射入傾斜面68的光返回反射，所以可減少 在將從光射入端面33a、33b射入的光朝導光板本體63導 光的途中從傾斜面68漏出的光，從而可提高光的利用效 率。藉此，可提高面光源裝置61的亮度。尤其是在使用 L E D光丨原作為光源4 1 a、4 1 b的情況下，以使用此種導光 板為佳。 又’圖12之導光板32a、32b中雖未設置光導入部62 ’但亦可於導光板32a、32b之端部設置光導入部62。 圖1 3為顯示使用於實施形態2之面光源裝置6丨的導 光板32a(或導光板32b)的又一例之立體圖。在圖13之導 光板32a(或導光板32b)中，在與各光源41a(或光源41b) 對應之位置’於光移行部64之傾斜面68設有呈大致半圓 錐台形的膨出部73。於膨出部73之外周面連續地形成有 多個V槽74。在此種導光板32a、32b中，從垂直於導光板 32&、3213之方向觀察時，各¥槽74係以各光源41&、411) -23- 201235614 為中心排列成放射狀，所以可減少在將射入光導入部62 之光朝導光板本體63導光之途中從傾斜面65漏出的光， 從而可進一步提高光之利用效率。 [第3實施形態] 圖14為顯示本發明實施形態3之面光源裝置8 1的示 意剖面圖。此面光源裝置8丨的特徵為，前面側的導光板 32a的厚度薄於背面侧的導光板32b的厚度。藉由將導光 板32a的厚度薄化，可減少從導光板32b射出的光在穿透 導光板32a時因產生的吸收或散射等而造成穿透損失。例 如’圖15為模擬穿透厚度為oimm〜3mm之導光板32a的 光的穿透損失之結果。在此，穿透導光板3 2a之光的穿透 損失係指，在光穿透導光板32a之際，若將射入導光板32a 背面之光的光度設為α ’將從導光板32a前面射出之光的 光度設為β時，以1〇〇χ(α_β)/α[% ]表示。因此，藉由將導 光板32a的厚度薄化，可減少穿透導光板32a之光的穿透 損失，所以可減少點亮光源41a時與點亮光源41b時的亮 度差。 另外，由於難以成形厚度薄於〇lmm的導光板，所 以導光板32a的厚度較佳為〇lmm以上。此外，一般，導 光板的厚度為0.3mm左右，故若使用〇 3mm的厚度作為導 ，板32b ’導光板32a的厚度較佳為比導光板32b的厚度還 薄，且比導光板32b的厚度的ι/g倍還厚。 [第4實施形態] 圖1 6為顯示本發明實施形能4少而水 肛心恶4之面先源裝置9 1的立 體圖。此面光源裝置91中，力 ^在配置於前面侧的導光板32a -24- 201235614 的前面，設有雙凸透鏡圖案92a，在背面設有擴散圖案37a 。同樣地，在配置於背面側的導光板3 2b的前面設有擴散 圖案37b，在背面設有雙凸透鏡圖案92b。 雙凸透鏡圖案92a、9 2b(以下，稱為雙凸透鏡圖案。 )為雙凸透鏡沿導光板3 2a、3 2b的寬度方向按一定間距排 列而成。又’擴散圖案37a、37b係呈凸狀或凹狀的微細 圖案，設成例如三角稜鏡狀。此外，亦可與圖1 6相反， 在導光板32a的前面設置擴散圖案37a，在導光板32a的背 面設置雙凸透鏡圖案92a。又，亦可在導光板3 2b的前面 設置雙凸透鏡圖案92b，在導光板32b的背面設置擴散圖 案 37b。 圖17(A)為設置於導光板32a之雙凸透鏡圖案92a的 放大圖，圖17(B)為設置於導光板3 2b之雙凸透鏡圖案9 2b 的放大圖。於導光板32a設有表面曲率小且邊緣角度ea 較小的雙凸透鏡圖案92a，於導光板32b設有表面曲率大 且邊緣角度0b較大的雙凸透鏡圖案92b。在此，邊緣角度 係指’如圖1 7所示之0a、0b，設想與雙凸透鏡呈圓筒狀 之表面下端相切的切面N，以雙凸透鏡圖案的底面為基準 所測得之該切面N的角度。 實施形態4中’由於是使設置於背面側的導光板32b 之雙凸透鏡圖案92b的邊緣角度9b大於導光板32a之雙凸 透鏡圖案92a的邊緣角度ea(即，0b>ea)，所以雙凸透鏡圖 案92b的表面曲率變大且透鏡作用變強。因此，從導光板 3 2b射出之光的指向性變窄，峰值方向之光的亮度變高。 圖18為顯示設置於導光板之雙凸透鏡圖案的邊緣角 -25- 201235614 度、與從導光板射出之光的亮度比及指向性的關係。在 此’免度比係指，從導光板射出之光的強度相對於從導 光板射出之光的亮度的最大値（飽和値）之比。又，指向 性為顯示從導光板射出之光強度的分布中成為峰值強度 之1/2之角度的擴展（半値全角）。根據圖18，得知隨著雙 凸透鏡圖案的邊緣角度變大’指向性變窄且亮度比增加 。又’根據圖18’當邊緣角度成為60。以上時，亮度比飽 和而不會改變，所以導光板32]3之雙凸透鏡圖案92b的邊 緣角度0b較佳為設成0a< eb$ 60。。又，當邊緣角度成為 θ 〇 (約2 1。）以上時，亮度比的增加變缓和，所以較佳為設 成 ea< θο 或 ea< θο< ebg 60。。 [第5實施形態] 圖1 9為顯示本發明實施形態5之面光源裝置93的示 意剖面圖。此面光源裝置9 3中，在配置於前面側的導光 板32a的前面’設有雙凸透鏡圖案92a，在背面設有擴散 圖案3 7a。又，在配置於背面側的導光板3 2b的前面設有 擴散圖案37b ’在背面設有雙凸透鏡圖案92b。 實施形態5中，如圖20(A)及圖20(B)所示，前面侧導 光板32a的背面之擴散圖案37a的圖案密度小於背面側的 導光板32b的前面之擴散圖案37b的圖案密度。若將前面 側的導光板32a的圖案密度變小，則被擴散圖案37a全反 射而從光射出面射出的光量會減少，發光亮度會降低。 因此，若將導光板32a的圖案密度設成小於導光板32b的 圖案密度’可減小光源4 1 a點亮時之面光源裝置9 3的發光 亮度、和光源41b點亮時之面光源裝置93的發光亮度的亮 -26- 201235614 度差。再者，將前面側的導光板32a的圖案密度變小時， 在導光板32b發出的光被導光板323散射的量會變小，光 源4 1 b點亮時之面光源裝置93的發光亮度會變大。其結果 ，光源41 a點亮時之面光源裝置93的發光亮度、和光源41b 點亮時之面光源裝置93的發光亮度的亮度差會變小。 圖2 1為顯示導光板的圖案密度比和亮度比的關係。 導光板的圖案密度比係指：（前面側的導光板32a之擴散 圖案37a的圖案密度）/(背面侧的導光板32b之擴散圖案 3 7b的圖案拔度）；亮度比係指：（點亮光源4 1 b時之導光 板32b的光射出面的發光亮度）/(點亮光源4U時之導光板 32a的光射出面的發光亮度）。在前面側與背面側使用相 同導光板及相同光源的情況，點亮前面側的光源時和點 亮背面側的光源時面光源裝置之發光亮度的比為最大 1.5倍，所以，參照圖21得知，擴散圖案37a的圖案密度 只要設成擴散圖案37b的圖案密度的〇5倍以上且小於^ 倍即可。 又’亦可使前面側導光板32a的背面之擴散圖案37a 所形成的表面杈度小於背面側導光板3 2 b的前面之擴散 圖案37b所形成的表面粗度，來取代使圖案密度不同。在 此表面4度係4曰鼻術平均粗度Ra，其因擴散圖案的 度所形成。 ° 【圖式簡單說明】 圖1 (A)為顯不專利文獻1所揭示之立體顯示裝置的 構造之不意圖。圖1 (B)為顯示該立體顯示裝置中從導光 板射出之光的路徑之圖。 -27- 201235614 圖2為本發明之實施形態1之面光源裝置的 圖3為實施形態i之面光源裝置的示意剖面 圖4(A)為顯示光源的亮度與流通於光源的 關係圖；圖4(B)為顯示光源的亮度與從光源發 的關係圖；圖4(C)為顯示光源的亮度與光源内 數量的關係圖。 圖5為在前面側和背面側配置有不同數重 面光源裝置的俯視圖。 圖6為顯示使用實施形態1的面光源裝置的 裝置的一例之示意剖面圖。 圖7為本發明實施形態2之面光源裝置的示 〇 圖8為使用於實施形態2之面光源裝置的導 體圖。 圖9為顯示設有光導入部之導光板表面的 小與該階差的損失之關係圖。 圖10(A)為顯示實施形態2的變形例之面光 示意剖面圖。圖10(B)為顯示實施形態2的其他 面光源裝置的示意剖面圖。 圖11為顯示使用於實施形態2之面光源裝 導光板的立體圖。 圖1 2為顯示使用於實施形態2之面光源裝 導光板的立體圖。 圖1 3為顯示使用於實施形態2之面光源裝 導光板的立體圖。 立體圖。 圖。 電流値的 出之光束 之LED的 的光源之 立體顯示 意剖面圖 光板之立 階差的大 源裝置的 變形例之 置的其他 置的另一 置的又一 -28- 201235614 β aA '音别面 圖1 4為本發明實施形態3之面光源裝置，不，V> 圖。 圖1 5為顯示前面側的導光板的穿透損失辛月j 導光板的厚度之關係圖。 圖1 6為本發明實施形態4之面光源裝置的立體圖 圖1 7(A)為設置於前面侧的導光板之雙凸透鏡圖案 的示意剖面圖。圖！ 7(B)為設置於背面側的導光板之芰 透鏡圖案的示意剖面圖。 圖18為顯示雙凸透鏡圖案的邊緣角度與冗度比及 向性的關係圖。 圖1 9為顯示本發明實施形態5之面光源裝置的示意 剖面圖。 圖20(A)為顯示前面側的導光板的背面之示意圖’圖 20(B)為顯示背面側的導光板的前面之示意圖。 圖2 1為顯示前面侧導光板的圖案密度比與亮度比的 關係圖。 【主要元件符號說明】 面光源裝置 導光體 導光板 光射入端面 低折射率層 擴散圖案 左側照明光 31 '61、 71、 72、 81 、 91 、 93 32 32a 、 32b 33a、 33b 36 37a、37b 38a -29- 201235614 38b 右 側 昭 明 光 40 反 射 構件 41b、 41a 光 源 42 LED 晶 片 43 透 明 樹脂 44 被 覆 部 45a ' 45b 撓 性 印 刷 基 板 51 立 體 顯 示 裝 置 53 光 學 片 53a 稜 鏡 列 53b 圓 筒 透 鏡 列 54 液 晶 面 板 55a 左 眼 55b 右 眼 62 光 導 入 部 63 導 光 板 本 體 64 光 移 行 部 68 傾 斜 面 92a、 92b 雙 凸 透 鏡 圖 案 -30-Ha). The reason is as follows: At present, since it is impossible to produce a light guide plate having a thickness of 匪 or less, the light guide plate body 63 can be made to have a minimum thickness of about 〇1 mm in the light guide plate having the shape of the present embodiment. Further, at present, since the heights of the light sources 41a and 41b which are generally used are 〇5 mm, when the thickness of the light guide body 32 is made to match the heights of the light sources 41a and 41b, the thickness of the other light guide plate main body 63 becomes 〇. 4mm or less. Therefore, in this embodiment, the step Hb of the light guide plate 32b (=the thickness of the light guide plate main body 63 of the light guide plate 32a) becomes the step Ha of the light guide plate 32a (=the thickness of the light guide plate main body 63 of the light guide plate 32b) /4 times more. However, even if the step Hb of the light guide plate 32b on the back side is set to a minimum (0.1 mm) 'there is not enough to equalize the brightness of the light guide plate 32a and the light guide plate 32b, the whole of the surface light source device 6 1 is not limited. The point 'with a uniform thickness' can also reduce the difference in luminance between the light guide plates 32a and 32b by setting the step Hb of the light guide plate 32b to be smaller than 1/4 of the step Ha of the light guide plate 32a. In addition, 'the case where the light introduction portion protrudes from the front surface and the back surface of the light guide plate main body, and the like, 'the difference between the thickness of the light introduction portion 62 of the light guide plate 3 2b on the back side and the thickness of the light guide plate main body 63 is set. The difference between the thickness of the light introducing portion 62 of the light guide plate 32a on the front side and the thickness of the light guide plate body 63 may be smaller. [Modification of Second Embodiment] Fig. 10 (A) is a schematic cross-sectional view showing a modification of the second embodiment. In the surface light source device 71, the height of each of the light introducing portions 62 of the light guiding plates 32a and 32b, and the total thickness of each of the light guiding plate bodies 63 of the light guide plates 32a and 32b which are overlapped, and the heights of the light sources 41a and 41b are each other. Almost equal. In the surface light source device 71, since the overall thickness is substantially uniform, it is easy to assemble into a backlight. The optical sheet and the liquid crystal panel can be stabilized, and productivity can be improved. Fig. 10 (B) is a schematic cross-sectional view showing another modification of the second embodiment. As shown in the surface light source device 72, if the step difference Hb between the light introducing portion 62 of the light guiding plate 32b and the light guiding plate main body 63 is smaller than the step difference Ha between the light introducing portion 62 of the light guiding plate 32a and the light guiding plate main body 63, The thickness of the light guide plate main body 63 of the light guide plate 32b may be the same as the thickness of the light guide plate main body 63 of the light guide plate 32a. Fig. 11 is a perspective view showing another example of the light guide plate 32a (or the light guide plate 32b) used in the surface light source device 6A of the second embodiment. Further, the cross section of the V-groove 69 is shown together in the figure 丨. In the light guide plate 32a (or the light guide plate 32b) of Fig. 13, a plurality of fine v-grooves are arranged in parallel and continuously along the inclined surface 68 of the light-transferring portion 64. In the case where the light guide plates 32a and 32b are used, the light incident on the inclined surface 68 from the light introduction portion 62 side can be reflected back by the V groove 69. Therefore, the light incident on the light introduction portion 62 can be reduced. The light leaking from the inclined surface 68 during the light guiding of the light guide body 63 can improve the utilization efficiency of the light -22-201235614. Thereby, the brightness of the surface light source device 6 can be increased. Fig. 12 is a perspective view showing another example of the light guide plate 32a (or the light guide plate 32b) used in the surface light source device 6A of the second embodiment. In the light guide plate 32a (or the light guide plate 32b) of Fig. 12, a pattern region 70 having a substantially fan shape is formed on the inclined surface 68 of the light transfer portion 64 before the respective light sources 41a (or the light source 41b). In each of the pattern regions 70, a plurality of fine v grooves 69 are formed in a radiating shape. When viewed from a direction perpendicular to the body plane 67, the V-groove 69 in front of each of the light sources 41a (or the light source 41b) is formed radially around the light-emitting point of each light source 41a (or the light source 41b) or a point near it. . When the light guide plates 32a and 32b shown in Fig. 12 are used, the light incident on the inclined surface 68 from the light incident end surface 33a can be reflected and reflected by the v groove 69, so that the light incident from the end face can be reduced. The light incident on the inclined light guide surface 68 in the middle of the light guided by the light guide plate main body 63 by the light incident from 33a and 33b can improve the light use efficiency. Thereby, the brightness of the surface light source device 61 can be improved. In particular, in the case where the L E D diaphragm is used as the light sources 4 1 a, 4 1 b, it is preferable to use such a light guide plate. Further, although the light introducing portions 62' are not provided in the light guiding plates 32a and 32b of Fig. 12, the light introducing portions 62 may be provided at the end portions of the light guiding plates 32a and 32b. Fig. 13 is a perspective view showing still another example of the light guide plate 32a (or the light guide plate 32b) used in the surface light source device 6A of the second embodiment. In the light guide plate 32a (or the light guide plate 32b) of Fig. 13, a bulging portion 73 having a substantially semi-reangular shape is provided on the inclined surface 68 of the light transfer portion 64 at a position corresponding to each of the light sources 41a (or the light source 41b). . A plurality of V grooves 74 are continuously formed on the outer peripheral surface of the bulging portion 73. In the light guide plates 32a and 32b, when viewed from a direction perpendicular to the light guide plates 32 & 3213, each of the light guide grooves 74 is radially arranged around the respective light sources 41 & 411) -23 - 201235614. The light leaking from the inclined surface 65 in the middle of guiding the light incident on the light introducing portion 62 toward the light guide plate main body 63 is reduced, and the light use efficiency can be further improved. [Third Embodiment] Fig. 14 is a schematic cross-sectional view showing a surface light source device 8 1 according to a third embodiment of the present invention. This surface light source device 8A is characterized in that the thickness of the light guide plate 32a on the front side is thinner than the thickness of the light guide plate 32b on the back side. By thinning the thickness of the light guide plate 32a, it is possible to reduce the penetration loss caused by absorption or scattering generated by the light emitted from the light guide plate 32b when penetrating the light guide plate 32a. For example, Fig. 15 is a result of simulating the penetration loss of light passing through the light guide plate 32a having a thickness of oi mm 3 mm. Here, the penetration loss of the light that penetrates the light guide plate 32a means that the luminosity of the light incident on the back surface of the light guide plate 32a is set to α' from the front of the light guide plate 32a when the light passes through the light guide plate 32a. When the luminosity of the emitted light is β, it is expressed by 1 〇〇χ (α_β) / α [% ]. Therefore, by reducing the thickness of the light guide plate 32a, the penetration loss of light passing through the light guide plate 32a can be reduced, so that the difference in brightness when the light source 41a is turned on and when the light source 41b is turned on can be reduced. Further, since it is difficult to form a light guide plate having a thickness thinner than 〇1 mm, the thickness of the light guide plate 32a is preferably 〇1 mm or more. Further, in general, the thickness of the light guide plate is about 0.3 mm, so if the thickness of 〇3 mm is used as the guide, the thickness of the light guide plate 32a of the plate 32b' is preferably thinner than the thickness of the light guide plate 32b, and is thicker than the thickness of the light guide plate 32b. The ι/g times are still thick. [Fourth Embodiment] Fig. 16 is a perspective view showing a surface source device 9 1 having a small form of water and an anal heart 4 in the present invention. In the surface light source device 91, a force is applied to the front surface of the light guide plate 32a - 24 to 201235614 disposed on the front side, and a lenticular lens pattern 92a is provided, and a diffusion pattern 37a is provided on the back surface. Similarly, a diffusion pattern 37b is provided on the front surface of the light guide plate 3 2b disposed on the back side, and a lenticular lens pattern 92b is provided on the back surface. The lenticular lens patterns 92a and 92b (hereinafter referred to as lenticular lens patterns) are formed by lenticular lenses arranged at a constant pitch along the width direction of the light guide plates 3 2a and 3 2b. Further, the diffusion patterns 37a and 37b have a fine pattern of a convex shape or a concave shape, and are formed, for example, in a triangular shape. Further, in contrast to Fig. 16, a diffusion pattern 37a may be provided on the front surface of the light guide plate 32a, and a lenticular lens pattern 92a may be provided on the back surface of the light guide plate 32a. Further, a lenticular lens pattern 92b may be provided on the front surface of the light guide plate 32b, and a diffusion pattern 37b may be provided on the back surface of the light guide plate 32b. Fig. 17(A) is an enlarged view of the lenticular lens pattern 92a provided on the light guide plate 32a, and Fig. 17(B) is an enlarged view of the lenticular lens pattern 9 2b provided on the light guide plate 32b. The light guide plate 32a is provided with a lenticular lens pattern 92a having a small surface curvature and a small edge angle ea, and the light guide plate 32b is provided with a lenticular lens pattern 92b having a large surface curvature and a large edge angle 0b. Here, the edge angle means '0a, 0b as shown in FIG. 17. The cut surface N which is tangent to the lower end of the cylindrical surface of the lenticular lens is assumed, and the cut surface is measured based on the bottom surface of the lenticular lens pattern. The angle of N. In the fourth embodiment, the lenticular lens pattern is such that the edge angle 9b of the lenticular lens pattern 92b of the light guide plate 32b provided on the back surface side is larger than the edge angle ea of the lenticular lens pattern 92a of the light guide plate 32a (i.e., 0b > ea). The surface curvature of 92b becomes large and the lens action becomes strong. Therefore, the directivity of the light emitted from the light guide plate 3 2b is narrowed, and the brightness of the light in the peak direction is increased. Fig. 18 is a view showing the relationship between the luminance ratio of the light emitted from the light guide plate and the directivity at an edge angle of -25 - 201235614 degrees of the lenticular lens pattern provided on the light guide plate. Here, the ratio is the ratio of the intensity of light emitted from the light guide plate to the maximum 値 (saturation 値) of the brightness of the light emitted from the light guide plate. Further, the directivity is an extension (full half angle) which is an angle which becomes 1/2 of the peak intensity in the distribution of the light intensity emitted from the light guide plate. According to Fig. 18, it is found that as the edge angle of the lenticular lens pattern becomes larger, the directivity is narrowed and the luminance ratio is increased. Further, according to Fig. 18, the edge angle becomes 60. In the above case, the luminance ratio is saturated without changing, so that the edge angle 0b of the lenticular lens pattern 92b of the light guide plate 32]3 is preferably set to 0a < eb$ 60. . Further, when the edge angle is θ 〇 (about 2 1 or more), the increase in the luminance ratio is moderated, so it is preferable to set ea < θο or ea < θο < ebg 60. . [Fifth Embodiment] Fig. 19 is a schematic cross-sectional view showing a surface light source device 93 according to a fifth embodiment of the present invention. In the surface light source device 9.3, a lenticular lens pattern 92a is provided on the front surface of the light guide plate 32a disposed on the front side, and a diffusion pattern 377a is provided on the back surface. Further, a diffusion pattern 37b is provided on the front surface of the light guide plate 3 2b disposed on the back side, and a lenticular lens pattern 92b is provided on the back surface. In the fifth embodiment, as shown in Figs. 20(A) and 20(B), the pattern density of the diffusion pattern 37a on the back surface of the front side light guide plate 32a is smaller than the pattern density of the diffusion pattern 37b on the front surface of the light guide plate 32b on the back side. . When the pattern density of the light guide plate 32a on the front side is reduced, the amount of light that is totally reflected by the diffusion pattern 37a and emitted from the light exit surface is reduced, and the light emission luminance is lowered. Therefore, if the pattern density of the light guide plate 32a is set to be smaller than the pattern density of the light guide plate 32b, the light-emitting luminance of the surface light source device 93 when the light source 41a is turned on and the surface light source device when the light source 41b is turned on can be reduced. The brightness of 93 is bright -26- 201235614 degree difference. Further, when the pattern density of the light guide plate 32a on the front side is reduced, the amount of light emitted from the light guide plate 32b by the light guide plate 323 becomes small, and the light emission luminance of the surface light source device 93 when the light source 4 1 b is turned on Become bigger. As a result, the luminance difference between the light-emitting luminance of the surface light source device 93 when the light source 41a is turned on and the light-emitting luminance of the surface light source device 93 when the light source 41b is turned on becomes small. Fig. 21 is a graph showing the relationship between the pattern density ratio of the light guide plate and the luminance ratio. The pattern density ratio of the light guide plate means: (the pattern density of the diffusion pattern 37a of the light guide plate 32a on the front side) / (the pattern extraction degree of the diffusion pattern 37b of the light guide plate 32b on the back side); the brightness ratio means: The light-emitting luminance of the light-emitting surface of the light guide plate 32b when the light source 4 1b is bright)/(the light-emitting luminance of the light-emitting surface of the light guide plate 32a when the light source 4U is turned on). When the same light guide plate and the same light source are used on the front side and the back side, the ratio of the light-emitting luminance of the surface light source device when the light source on the front side is turned on and the light source on the back side is turned up to 1.5 times. Therefore, referring to FIG. 21 It is to be understood that the pattern density of the diffusion pattern 37a may be set to be 〇5 times or more and less than 2 times the pattern density of the diffusion pattern 37b. Further, the surface roughness of the diffusion pattern 37a formed on the back surface of the front side light guide plate 32a may be made smaller than the surface roughness of the diffusion pattern 37b formed on the front surface of the back side light guide plate 32b instead of the pattern density. On this surface, the average degree of roughness Ra of the nose is 4 degrees, which is formed by the degree of diffusion pattern. [Brief Description of the Drawings] Fig. 1 (A) is a schematic view showing the configuration of a stereoscopic display device disclosed in Patent Document 1. Fig. 1(B) is a view showing a path of light emitted from a light guide plate in the stereoscopic display device. -27- 201235614 FIG. 2 is a schematic cross-sectional view of a surface light source device according to Embodiment 1 of the present invention; FIG. 3 is a schematic cross-sectional view showing a relationship between brightness of a light source and a light source; FIG. 4(B) is a graph showing the relationship between the brightness of the light source and the light source; FIG. 4(C) is a graph showing the relationship between the brightness of the light source and the number of light sources. Fig. 5 is a plan view showing a device for arranging different numbers of surface light sources on the front side and the back side. Fig. 6 is a schematic cross-sectional view showing an example of an apparatus using the surface light source device of the first embodiment. Fig. 7 is a view showing a surface light source device according to a second embodiment of the present invention. Fig. 8 is a view showing a surface light source device used in the second embodiment. Fig. 9 is a view showing the relationship between the small surface of the light guide plate provided with the light introducing portion and the loss of the step. Fig. 10 (A) is a schematic cross-sectional view showing a surface light of a modification of the second embodiment. Fig. 10 (B) is a schematic cross-sectional view showing another surface light source device of the second embodiment. Fig. 11 is a perspective view showing a light guide plate used in the surface light source of the second embodiment. Fig. 12 is a perspective view showing a light guide plate used in the surface light source of the second embodiment. Fig. 13 is a perspective view showing a light guide plate used in the surface light source of the second embodiment. Stereo picture. Figure. The stereoscopic display of the light source of the LED of the current beam, the cross-sectional view of the light source, and the other example of the modification of the large-source device of the light source plate. Another set is another -28-201235614 β aA ' sound Fig. 14 is a surface light source device according to Embodiment 3 of the present invention, and is not a V> diagram. Fig. 15 is a graph showing the relationship between the penetration loss of the light guide plate on the front side and the thickness of the light guide plate. Fig. 16 is a perspective view showing a surface light source device according to a fourth embodiment of the present invention. Fig. 17 (A) is a schematic cross-sectional view showing a lenticular lens pattern of a light guide plate provided on the front side. Figure! 7(B) is a schematic cross-sectional view of the 透镜 lens pattern of the light guide plate provided on the back side. Fig. 18 is a graph showing the relationship between the edge angle of the lenticular lens pattern and the redundancy ratio and the directivity. Fig. 19 is a schematic cross-sectional view showing a surface light source device according to a fifth embodiment of the present invention. Fig. 20(A) is a schematic view showing the back surface of the light guide plate on the front side. Fig. 20(B) is a schematic view showing the front surface of the light guide plate on the back side. Fig. 21 is a graph showing the relationship between the pattern density ratio and the luminance ratio of the front side light guide plate. [Description of main component symbols] Surface light source device Light guide light guide plate light incident end face low refractive index layer diffusion pattern left side illumination light 31 '61, 71, 72, 81, 91, 93 32 32a, 32b 33a, 33b 36 37a, 37b 38a -29- 201235614 38b Right side Vision light 40 Reflecting members 41b, 41a Light source 42 LED wafer 43 Transparent resin 44 Covered portion 45a '45b Flexible printed circuit board 51 Stereoscopic display device 53 Optical sheet 53a Array 53b Cylindrical lens array 54 Liquid crystal panel 55a Left eye 55b Right eye 62 Light introduction portion 63 Light guide plate body 64 Light transfer portion 68 Inclined surface 92a, 92b lenticular lens pattern -30-

Claims (1)

201235614 七、申請專利範圍： 1. 一種面光源裝置’係具備：一對導光板，係以前面與 背面對向的方式重疊；前面側的光源，係與位於前面 側的導光板的一端面對向而配置；及背面側的光源， 係與位於背面側的導光板的一端面對向而配置； 其特徵為： 没成僅使前述前面側的光源點亮以使光從前述前 面側的導光板的光射出面射出時的發光亮度、和僅使 刖述背面側的光源點亮以使光從前述背面側的導光板 的光射出面射出時通過前述前面側的導光板所觀察到 的發光亮度成為相同亮度。 2. 如申明專利範圍第1項之面光源裝置，其中僅點亮前述 背面側的光源時之前述背面側的導光板之光射出面的 發光亮度，係高於僅點亮前述前面側的光源時之前述 前面侧的導光板之光射出面的發光亮度。 3. 如申請專利範圍第1項之面光源裝置，其中前述背面側 之光源的亮度係高於前述前面側之光源的亮度。 4. 如申請專利範圍第3項之面光源裝置，其中前述背面側 之光源的光度係大於前述前面側之光源的光度。 5. 如申請專利範圍第4項之面光源裝置，其中前述背面側 之光源的光度係為前述前面側之光源的光度的1.5倍以 下。 6. 如申請專利範圍第丨項之面光源裝置，其中前述背面側 的導光板的光射出效率比前述前面側的導光板的光射 出效率還高。 -31- 201235614 7.如申請專利範圍第6項之面光源裝置，其中前述前面 的導光板及前述背面側的導光板係具有： 成為發光區域之厚度較薄的導光板本體； 光導入部，其至少一部分具有比前述導光板本 更大的厚度，並使前述前面側或前述背面側的光源 向配置於端面；以及 光移行部’以使前述導光板本體和前述光導入 連接的方式改變厚度； 則述背面側的導光板之前述光導入部與前述導 板本體的厚度差係小於前述前面側的導光板之前述 導入部與前述導光板本體的厚度差。 8 ·如申請專利範圍第7項之面光源裝置，其中前述前面 的導光板及前述背面側的導光板各自之前述光導入 的厚度，係與前述前面側的導光板之導光板本體的 度及前述背面侧的導光板之導光板本體的厚度之和 等。 9·如申請專利範圍第8項之面光源裝置，其中前述背面 =導光板的前述光導入部係由該導光板本體的前面 則方突出’前述前面側的導光板的前述光導入部係 該導光板本體的背面朝後方突出； 月;J述背面侧的導光板之前述光導入部與前述導 板本體的厚度差為前述前面側的導光板之前述光導 部與前述導光板本體的厚度差的1/4倍以上。 .士申响專利範圍第丨項之面光源裝置，其中前述前面 的導光板的穿透損失係小於前述背面側的導光板的 透損失。 側 體 對 部 光 光 側 部 厚 相 側 朝 由 光 入 側 穿 -32- 201235614 ιι·如申請專利範圍第1〇項之面光源裝置，其中於 面側的導光板及前述背面側的導光板各自之前 面的任-者，形成擴散圖案，使前述前面側的 之前述擴散圖案的圖案密度或表面粗度小於前 側的導光板之前述擴散圓案的圖案密度或表面: I2·如申請專利範圍第11項之面光源裝置，其中前 側的導光板之前述擴散圖案的圖案密度或表= 係為前述背面側的導光板之前述擴散圖案的圖 或表面粗度的1/2以上。 13. 如申請專利範圍第1〇項之面光源裝置，其中前 侧的導光板之發光區域的厚度係薄於前述背= , 光板之發光區域的厚度。 14. 如申請專利範圍第13項之面光源叢置，其中前 側的導光板之發光區域的厚度係厚於前述背面 光板之發光區域的厚度的1/3倍。 15. 如申請專利範圍第1項之面光源裝置，其中從前 側的導光板的光射出面射出之光的指向性係窄 述前面側的導光板的光射出面射出之光的指向，f 16. 如申請專利範圍第15項之面光源裝置，其中使 雙凸透鏡排列於前述前面側的導光板和前述背 導光板各自的前面和背面中的任—者，使前述 的導光板之前述雙凸透鏡的邊緣角度大於前述 的導光板之前述雙凸透鏡的邊緣角度。 1 7.如申請專利範圍第1 6項之面光源裝置，其中前 側的導光板之前述雙凸透鏡的邊緣角度為6〇。以 前述前 面與背 導光板 述背面 Ja度。 述前面 粗度， 案密度 述前面 側的導 述前面 側的導 述背面 於從前 生。 複數個 面側的 背面側 前面側 述背面 下。 -33- 201235614 18.- 有 種立體顯示裝置，其特徵為： 於申請專利範圍第1項之面光源裝置的前方，配置 光學片及液晶面板。 -34-201235614 VII. Patent application scope: 1. A surface light source device is provided with: a pair of light guide plates overlapping the front and back sides; the front side light source is facing the one end of the light guide plate located at the front side And the light source on the back side is disposed facing the one end of the light guide plate located on the back side; and is characterized in that: the light source of the front side is not illuminated to guide the light from the front side The light-emitting luminance when the light-emitting surface of the light-emitting panel is emitted, and the light-emitting light that is observed by the light guide plate on the front side when the light source on the back surface side is illuminated to emit light from the light-emitting surface of the light guide plate on the back surface side The brightness becomes the same brightness. 2. The surface light source device according to claim 1, wherein the light-emitting luminance of the light-emitting surface of the light-guiding plate on the back surface side when the light source on the back surface side is illuminated is higher than the light source that only lights the front side At the time of the light emission luminance of the light exit surface of the light guide plate on the front side. 3. The surface light source device of claim 1, wherein the brightness of the light source on the back side is higher than the brightness of the light source on the front side. 4. The surface light source device of claim 3, wherein the illuminance of the light source on the back side is greater than the illuminance of the light source on the front side. 5. The surface light source device of claim 4, wherein the illuminance of the light source on the back side is 1.5 times or less of the illuminance of the light source on the front side. 6. The surface light source device according to claim 2, wherein the light-emitting efficiency of the light guide plate on the back side is higher than the light-emitting efficiency of the light guide plate on the front side. 7. The surface light source device according to claim 6, wherein the front light guide plate and the light guide plate on the back side have a light guide plate body having a thin thickness as a light-emitting region; and a light introduction portion. At least a portion thereof has a thickness larger than that of the light guide plate, and the light source on the front side or the back side is disposed on the end surface; and the light transfer portion is changed in thickness in such a manner that the light guide plate body and the light are introduced and connected. The thickness difference between the light introducing portion of the light guide plate on the back side and the guide main body is smaller than the thickness difference between the introduction portion of the light guide plate on the front surface side and the light guide plate body. The surface light source device of claim 7, wherein the thickness of the light guide of each of the front light guide plate and the light guide plate on the back side is the same as the thickness of the light guide plate of the front side light guide plate. The sum of the thicknesses of the light guide plate body of the light guide plate on the back side. 9. The surface light source device according to claim 8, wherein the light-introducing portion of the front surface of the light guide plate protrudes from a front surface of the light guide plate body, and the light-introducing portion of the light guide plate on the front side is configured The back surface of the light guide plate body protrudes rearward; the thickness difference between the light introduction portion of the light guide plate on the back surface side and the guide plate body is the difference in thickness between the light guide portion and the light guide plate body of the light guide plate on the front side. More than 1/4 times. The surface light source device of the ninth aspect of the invention, wherein the front light guide plate has a penetration loss smaller than a permeability loss of the light guide plate on the back side. The surface light source side of the side of the light side of the side of the side of the side of the side of the side of the side of the side of the light side of the side of the light source device Any one of the former faces forms a diffusion pattern such that the pattern density or surface roughness of the diffusion pattern on the front side is smaller than the pattern density or surface of the diffusion pattern of the front side light guide plate: I2· In the surface light source device of the eleventh aspect, the pattern density or the surface of the diffusion pattern of the light guide plate on the front side is 1/2 or more of the map or the surface roughness of the diffusion pattern of the light guide plate on the back surface side. 13. The surface light source device of claim 1, wherein the thickness of the light-emitting region of the light guide plate on the front side is thinner than the thickness of the light-emitting region of the light plate. 14. The surface light source of claim 13 wherein the light-emitting area of the front side light guide plate is thicker than 1/3 times the thickness of the light-emitting area of the back light plate. 15. The surface light source device according to claim 1, wherein the directivity of the light emitted from the light exit surface of the light guide plate on the front side is a narrower direction of the light emitted from the light exit surface of the light guide plate on the front side, f 16 The surface light source device of claim 15, wherein the lenticular lens is arranged on the front surface and the back surface of each of the light guide plate and the front light guide plate on the front side, and the lenticular lens of the light guide plate is used. The edge angle is larger than the edge angle of the aforementioned lenticular lens of the light guide plate. 1. The surface light source device of claim 16, wherein the front lenticular lens of the front side light guide plate has an edge angle of 6 〇. The back side of the front surface and the back light guide plate are Ja degrees. The front thickness, the density of the front side of the guide on the front side is derived from the front. The back side of the plurality of sides is the back side of the front side. -33- 201235614 18.- There is a stereoscopic display device characterized in that an optical sheet and a liquid crystal panel are disposed in front of the surface light source device of the first application of the patent application. -34-
TW100142171A 2010-12-25 2011-11-18 Planar light source device and stereo display device TW201235614A (en)

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