JPH10289604A - Surface light source device - Google Patents

Surface light source device

Info

Publication number
JPH10289604A
JPH10289604A JP9098894A JP9889497A JPH10289604A JP H10289604 A JPH10289604 A JP H10289604A JP 9098894 A JP9098894 A JP 9098894A JP 9889497 A JP9889497 A JP 9889497A JP H10289604 A JPH10289604 A JP H10289604A
Authority
JP
Japan
Prior art keywords
light
light guide
emitted
plate
guide plate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP9098894A
Other languages
Japanese (ja)
Inventor
Yasuhiro Daiku
康宏 代工
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Casio Computer Co Ltd
Original Assignee
Casio Computer Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Casio Computer Co Ltd filed Critical Casio Computer Co Ltd
Priority to JP9098894A priority Critical patent/JPH10289604A/en
Priority to US08/878,412 priority patent/US5914760A/en
Priority to KR1019970026082A priority patent/KR100237405B1/en
Priority to EP97110147A priority patent/EP0814300A1/en
Priority to TW086108626A priority patent/TW346546B/en
Publication of JPH10289604A publication Critical patent/JPH10289604A/en
Pending legal-status Critical Current

Links

Landscapes

  • Light Guides In General And Applications Therefor (AREA)
  • Liquid Crystal (AREA)
  • Planar Illumination Modules (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide a surface light source device in which light from a light source disposed sideways is emitted from its surface, wherein almost all of light emitted from the surface is emitted to a direction of a desired range of angles including a front direction without dispersing the same the circumference, thereby increasing luminance in the range sufficiently and substantially equalizing luminance distribution therein. SOLUTION: On a staggered surface of a light guiding plate 1 which takes in light from an end face and emits the light from each rising surface 2a of the staggered surface, a plurality of prism parts 8 are formed, wherein a plurality of light guiding areas A are defined and incident light from each rising surface 2a of a light guiding plate 1 is taken into a rear surfaces of the prism part 8 to refract it to the light guiding areas A, and a plurality of lens parts 9 are formed, which refracts the light led to the light guiding areas A to the focusing direction and emits it to a front surfaces of the lens parts 9. Further, on both sides of each light guiding area A, light guiding members 6 which has light guiding faces 10 formed thereon are provided to refract the light which goes outside of the focusing lens 9, among those led to the light guiding areas A, and lead it to the focusing lens parts 9.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】この発明は、側方に配置した
光源部からの光を表面から出射する面光源装置に関する
ものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface light source device which emits light from a light source section disposed on a side from a surface.

【０００２】[0002]

【従来の技術】液晶表示装置のバックライト等に用いら
れる面光源装置として、光源部を側方に配置し、この光
源部からの光を表面から出射するものがあり、この種の
面光源装置は、一般にサイドランプ型と呼ばれている。2. Description of the Related Art As a surface light source device used for a backlight or the like of a liquid crystal display device, there is a surface light source device in which a light source portion is arranged on a side and light from the light source portion is emitted from a surface. Is generally called a side lamp type.

【０００３】このサイドランプ型の面光源装置として
は、従来、平板状の導光板を用い、この導光板の端面に
対向させて、直管状の蛍光ランプや、複数のＬＥＤ（発
光ダイオード）を整列させたＬＥＤアレイ等からなる光
源部を配置したものが知られている。Conventionally, as a side lamp type surface light source device, a flat light guide plate is used, and a straight tube fluorescent lamp and a plurality of LEDs (light emitting diodes) are arranged opposite to the end face of the light guide plate. There is known an arrangement in which a light source unit composed of an illuminated LED array or the like is arranged.

【０００４】この面光源装置は、その正面、つまり導光
板の表面を、液晶表示パネル等の被照明体の入射面に対
向させて使用されるものであり、前記光源部からの光は
導光板にその端面から取り込まれ、この導光板内を導か
れてその表面に出射する。This surface light source device is used with its front surface, that is, the surface of the light guide plate facing the incident surface of an illuminated object such as a liquid crystal display panel, and the light from the light source unit is used as the light guide plate. And is guided from the end face thereof, guided through the light guide plate and emitted to the surface.

【０００５】[0005]

【発明が解決しようとする課題】しかし、上記従来の面
光源装置は、導光板内を導かれてきた光が導光板の表面
から様々な方向に向かって出射するため、導光板表面に
対する角度が極く小さい方向に出射して周囲に放散する
無駄な出射光が多く、したがって、正面方向およびその
付近の方向に出射する光量が不足して高い正面輝度（正
面方向から観察したときの輝度）が得られないし、また
出射光の輝度分布も不均一であるという問題をもってい
る。However, in the above-mentioned conventional surface light source device, the light guided in the light guide plate is emitted from the surface of the light guide plate in various directions, and the angle with respect to the surface of the light guide plate is small. There is a lot of useless emitted light that is emitted in a very small direction and radiates to the surroundings. Therefore, the amount of light emitted in the front direction and the vicinity thereof is insufficient, and high front luminance (luminance when observed from the front direction) is high. However, there is a problem that the luminance distribution of the emitted light is not uniform.

【０００６】この発明は、側方に配置した光源部からの
光を表面から出射する面光源装置として、その表面から
出射する光のほとんどを、周囲に放散させることなく正
面方向を含む所望の角度範囲の方向に出射して、その範
囲の輝度を充分に高くすることができるとともに、その
輝度分布もほぼ均一にすることができるものを提供する
ことを目的としたものである。The present invention is directed to a surface light source device which emits light from a light source unit disposed on the side from a surface, and a desired angle including a front direction without dispersing most of the light emitted from the surface to the surroundings. It is an object of the present invention to provide a device that emits light in a direction of a range and can sufficiently increase the brightness in the range and can also make the brightness distribution substantially uniform.

【０００７】[0007]

【課題を解決するための手段】この発明の面光源装置
は、表面が階段状面となっており端面から光を取り込ん
でその光を前記階段状面の各立上がり面から出射する導
光板と、前記導光板の光取り込み端面に対向させて配置
された光源部と、前記導光板の表面に配置され、その階
段状面の各立上がり面から出射する光を導いて表面方向
に出射する導光部材とを備え、前記導光部材は、内部を
前記導光板の階段状面の段ピッチに対応するピッチで複
数の導光領域に区画する複数の導光面と、裏面に前記各
導光領域にそれぞれ対応させて前記導光板の階段状面の
各立上がり面から出射する光を取り込んでその光を対応
する導光領域に向けて屈折させる複数のプリズム部と、
表面に前記各導光領域にそれぞれ対応させて前記導光領
域を導かれた光を集光方向に向けてて出射する複数の集
光レンズ部とが形成され前記プリズム部で屈折されて前
記導光領域に導かれた光のうち、その導光領域に対応す
る集光レンズ部の外側に向かう光を前記導光面により屈
折させて前記集光レンズ部に導く透明板からなっている
ことを特徴とするものである。A surface light source device according to the present invention has a light guide plate that has a stepped surface, takes in light from an end face, and emits the light from each rising surface of the stepped surface. A light source unit disposed to face the light capturing end face of the light guide plate; and a light guide member disposed on the surface of the light guide plate and guiding light emitted from each rising surface of the stepped surface and emitting the light in the surface direction. The light guide member comprises a plurality of light guide surfaces that partition the inside into a plurality of light guide regions at a pitch corresponding to the step pitch of the stepped surface of the light guide plate, and the light guide regions on the back surface. A plurality of prism portions that take in light emitted from each rising surface of the step-like surface of the light guide plate and refract the light toward the corresponding light guide region, respectively.
A plurality of condensing lens portions for emitting light guided through the light guide region in the light condensing direction corresponding to the respective light guide regions are formed on the surface, and are refracted by the prism portion to form the light guide. Among the light guided to the light region, the light guide surface is formed of a transparent plate that is refracted by the light guide surface and guides the light toward the outside of the condenser lens portion corresponding to the light guide region. It is a feature.

【０００８】この面光源装置は、導光板の光取り込み端
面に対向させて配置した光源部からの光を前記導光板と
その表面に配置した導光部材とにより導いて表面方向に
出射するものであり、前記光源部からの光は、前記導光
板にその端面から取り込まれて導光板内を導かれ、階段
状面となっている導光板表面の各立上がり面から出射し
て、前記導光部材の裏面の各プリズム部にそれぞれ取り
込まれる。そして、前記各プリズム部に取り込まれた光
は、これらのプリズム部で屈折されて導光部材の各導光
領域を導かれ、その表面の各集光レンズ部により集光方
向に屈折されて出射する。In this surface light source device, light from a light source unit disposed opposite to a light-receiving end face of a light guide plate is guided by the light guide plate and a light guide member disposed on the surface thereof, and emitted toward the surface. The light from the light source unit is taken into the light guide plate from its end face and guided inside the light guide plate, and is emitted from each rising surface of the light guide plate surface that is a stepped surface, and the light guide member is provided. Are taken in by each prism part on the back surface of the. Then, the light taken into each of the prism portions is refracted by these prism portions, guided to each light guide region of the light guide member, and refracted in the light collecting direction by each of the light collecting lens portions on the surface thereof and emitted. I do.

【０００９】この場合、前記導光板にその端面から取り
込まれた光は、この導光板の表裏面で屈折しながら導光
板内を導かれてその階段状面の各立上がり面からある程
度の広がりをもって出射し、その光が前記導光部材の裏
面の各プリズム部に取り込まれて、このプリズム部への
入射角に応じた屈折角で屈折されて導光領域に導かれる
ため、前記導光部材の各導光領域を表面方向に向かって
進む光はある程度の広がりをもった光である。In this case, the light introduced into the light guide plate from the end surface is guided inside the light guide plate while being refracted on the front and back surfaces of the light guide plate, and is emitted with a certain spread from each rising surface of the stepped surface. Then, the light is taken into each prism portion on the back surface of the light guide member, is refracted at a refraction angle corresponding to the incident angle to the prism portion, and is guided to the light guide region. Light traveling in the light guide region toward the surface is light having a certain spread.

【００１０】そのため、前記導光領域を表面方向に導か
れる光のうち、ある広がり範囲内の光は、導光領域を直
進してその導光領域に対応する集光レンズ部に向かって
進み、それよりも広がり範囲の大きい光は前記集光レン
ズ部の外側に向かって進むが、この集光レンズ部の外側
に向う光は導光領域の両側の導光面で反射或は屈折され
て前記集光レンズ部に導かれるため、前記プリズム部か
ら取り込んだ光のほとんどをロスすることなく集光レン
ズ部に導くことができる。Therefore, of the light guided in the surface direction of the light guide region, light within a certain spread range goes straight through the light guide region toward the condenser lens portion corresponding to the light guide region, Light having a larger spread range proceeds toward the outside of the condenser lens portion, but light directed to the outside of the condenser lens portion is reflected or refracted by the light guide surfaces on both sides of the light guide region, and Since the light is guided to the condenser lens section, most of the light taken in from the prism section can be guided to the condenser lens section without loss.

【００１１】そして、前記集光レンズ部に入射した光
は、この集光レンズ部により集光方向に屈折されて出射
するが、前記導光領域を直進して集光レンズ部に入射し
た光、つまり集光レンズ部のレンズ光軸に沿った方向を
中心とする広がり方向に沿って前記集光レンズ部に入射
した光は、そのほとんどがほぼ正面方向（集光レンズ部
のレンズ光軸に沿った方向）に出射し、また前記導光面
で反射或は屈折して前記集光レンズ部に入射した光、つ
まり前記レンズ光軸に沿った方向を中心とする広がり方
向とは異なる方向から集光レンズ部に入射した光は、そ
のほとんどが正面方向に対してある程度の角度範囲の方
向に向かって出射する。The light that has entered the condenser lens section is refracted by the condenser lens section in the light-condensing direction and exits. However, the light that travels straight through the light-guiding region and enters the condenser lens section. In other words, most of the light incident on the condenser lens unit along the spreading direction centered on the direction along the lens optical axis of the condenser lens unit is almost in the front direction (along the lens optical axis of the condenser lens unit). Direction), and is reflected or refracted by the light guide surface and is incident on the condenser lens portion, that is, from the direction different from the spreading direction centered on the direction along the lens optical axis. Most of the light incident on the optical lens unit is emitted in a direction within a certain angle range with respect to the front direction.

【００１２】また、前記集光レンズ部に入射する光は、
導光領域を直進してきた光も、前記導光面で反射或は屈
折されて集光レンズ部に導かれた光も、ある広がりをも
った光であり、その光が集光レンズ部への入射角に応じ
て屈折されて出射するため、前記正面方向および正面方
向に対してある程度傾いた角度範囲の方向に出射する光
の輝度分布もほぼ均一である。The light incident on the condenser lens portion is
The light that has traveled straight through the light guide region, the light that has been reflected or refracted by the light guide surface and guided to the condenser lens unit is also light having a certain spread, and the light is transmitted to the condenser lens unit. Since the light is emitted after being refracted in accordance with the incident angle, the brightness distribution of the light emitted in the front direction and in the direction of the angle range slightly inclined with respect to the front direction is also substantially uniform.

【００１３】そして、前記集光レンズからの光の出射角
範囲は、この集光レンズ部のレンズ面の曲率を選ぶこと
によって任意に設定できるため、この面光源装置によれ
ば、その表面から出射する光のほとんどを、周囲に放散
させることなく正面方向を含む所望の角度範囲の方向に
出射して、その範囲の輝度を充分に高くすることができ
るとともに、その輝度分布もほぼ均一にすることができ
る。Further, the range of the emission angle of the light from the condenser lens can be arbitrarily set by selecting the curvature of the lens surface of the condenser lens portion. Most of the light to be emitted is emitted in the direction of a desired angle range including the front direction without dissipating to the surroundings, and the brightness in the range can be sufficiently increased, and the brightness distribution thereof is also substantially uniform. Can be.

【００１４】[0014]

【発明の実施の形態】この発明の面光源装置は、表面が
階段状面となっており、端面から光を取り込んでその光
を前記階段状面の各立上がり面から出射する導光板の表
面に、内部を複数の導光領域に区画し、裏面に前記導光
板の階段状面の各立上がり面から出射する光を取り込ん
でその光を対応する導光領域に向けて屈折させる複数の
プリズム部を形成し、表面に前記導光領域を導かれた光
を集光方向に屈折させて出射する複数の集光レンズ部を
形成するとともに、前記各導光領域の両側に、前記プリ
ズム部で屈折されて前記導光領域に導かれた光のうち、
その導光領域に対応する集光レンズ部の外側に向かう光
を屈折させて前記集光レンズ部に導く導光面を形成した
透明板からなる導光部材を配置することにより、前記導
光板の光取り込み端面に対向させて配置した光源部から
の光を前記導光板と導光部材とによって導いて表面方向
に出射するようにして、正面方向を含む所望の角度範囲
の方向に高輝度の光を出射させるとともに、その輝度分
布もほぼ均一にしたものである。DESCRIPTION OF THE PREFERRED EMBODIMENTS A surface light source device according to the present invention has a stepped surface, and receives light from an end surface and emits the light from each rising surface of the stepped surface to a surface of a light guide plate. A plurality of prism portions that divide the inside into a plurality of light guide regions, take in light emitted from each rising surface of the stepped surface of the light guide plate on the back surface, and refract the light toward the corresponding light guide region. Forming and forming a plurality of condensing lens portions for refracting the light guided to the light guiding region on the surface in the converging direction and emitting the light, and refracted by the prism portion on both sides of each light guiding region. Out of the light guided to the light guide region,
By arranging a light guide member made of a transparent plate having a light guide surface that refracts light directed to the outside of the condenser lens portion corresponding to the light guide region and guides the light to the condenser lens portion, High-brightness light is emitted in the direction of a desired angle range including the front direction by guiding the light from the light source unit disposed to face the light capturing end face by the light guide plate and the light guide member and emitting the light toward the surface direction. Is emitted and the luminance distribution is also made substantially uniform.

【００１５】この発明の面光源装置において、前記導光
部材の各導光領域の両側の導光面は、例えば、前記透明
板内の前記各導光領域の境界部に、光の屈折率が前記透
明板の屈折率よりも小さい物質からなる低屈折率層を設
けることによって形成でき、その場合は、前記低屈折率
層と前記透明板との界面が前記導光面となる。このよう
に前記透明板内の各領域の境界部に低屈折率層を設けて
前記導光面を形成する場合は、前記低屈折率層は空気層
でよい。In the surface light source device according to the present invention, the light guide surfaces on both sides of each light guide region of the light guide member have, for example, a refractive index of light at a boundary portion of each light guide region in the transparent plate. It can be formed by providing a low refractive index layer made of a material smaller than the refractive index of the transparent plate. In this case, the interface between the low refractive index layer and the transparent plate becomes the light guide surface. When the light guide surface is formed by providing the low refractive index layer at the boundary between the respective regions in the transparent plate, the low refractive index layer may be an air layer.

【００１６】[0016]

【実施例】以下、この発明を液晶表示装置のバックライ
トに用いる面光源装置に適用した一実施例を図１〜図３
を参照して説明する。図１は面光源装置のハッチングを
省略した断面図である。1 to 3 show an embodiment in which the present invention is applied to a surface light source device used for a backlight of a liquid crystal display device.
This will be described with reference to FIG. FIG. 1 is a sectional view of the surface light source device with hatching omitted.

【００１７】この面光源装置は、図１に示すように、導
光板１と、この導光板１の光取り込み端面に対向させて
その側方に配置された光源部３と、前記導光板１の表面
に配置された導光部材６とからなっている。As shown in FIG. 1, the surface light source device includes a light guide plate 1, a light source unit 3 disposed on a side of the light guide plate 1 so as to face a light receiving end face of the light guide plate 1, And a light guide member 6 disposed on the surface.

【００１８】前記導光板１は、アクリル樹脂等の透明樹
脂からなる成形品または切削加工品であり、その裏面は
平坦面とされ、表面は、一端側から他端側に向かって所
定ピッチで段階的に低くなる階段状面とされている。な
お、この階段状面の段ピッチは、液晶表示パネル（図示
せず）の画素ピッチと同じか、あるいは前記画素ピッチ
の整数分の１に設定されている。The light guide plate 1 is a molded product or a cut product made of a transparent resin such as an acrylic resin. The back surface is a flat surface, and the front surface is stepped at a predetermined pitch from one end to the other end. It is a stair-like surface that gradually becomes lower. Note that the step pitch of the stepped surface is set to be the same as the pixel pitch of the liquid crystal display panel (not shown), or set to a fraction of the pixel pitch.

【００１９】この導光板１は、前記一端側の端面（高さ
が大きい方の端面）から光を取り込んでその光を前記階
段状面の各段部２の立上がり面２ａから出射するもので
あり、光源部３から出射する実質的な平行光は、導光板
１にその光取り込み端面から取り込まれ、図１に矢線で
示すように、各階段面に平行に進む光は導光板１の立ち
上がり面２ａから直接的に出射し、また各階段面と交差
する方向に進む光は、導光板１の表裏面、つまり階段状
面の各段部２の表面と外気（空気）との界面および導光
板裏面と外気との界面で交互に屈折しながら導光板１内
を導かれて、前記階段状面の各立上がり面２ａから出射
する。The light guide plate 1 receives light from the end face on the one end side (the end face with the larger height) and emits the light from the rising face 2a of each step portion 2 of the stepped face. Substantially parallel light emitted from the light source unit 3 is taken into the light guide plate 1 from its light take-in end face, and light traveling parallel to each step surface as shown by arrows in FIG. Light emitted directly from the surface 2a and traveling in a direction intersecting with each stepped surface is the front and back surfaces of the light guide plate 1, that is, the interface between the surface of each stepped portion 2 of the stepped surface and the outside air (air) and the conduction. The light is guided inside the light guide plate 1 while being alternately refracted at the interface between the back surface of the light plate and the outside air, and exits from each rising surface 2a of the stepped surface.

【００２０】なお、この実施例で用いた光源３は、直管
状の蛍光ランプ４からなっており、その背後には、前記
蛍光ランプ４からの放射光を導光板１の光取り込み端面
に向けて反射させ実質的な平行光を得るためのリフレク
タ５が配置されている。The light source 3 used in this embodiment is a fluorescent lamp 4 having a straight tube shape, and the light emitted from the fluorescent lamp 4 is directed behind the fluorescent lamp 4 toward the light receiving end face of the light guide plate 1. A reflector 5 for reflecting and obtaining substantially parallel light is provided.

【００２１】また、前記導光板１の表面に配置した導光
部材６は、導光板表面の階段状面の各立上がり面２ａか
らの出射光を導いて表面方向に出射するものであり、こ
の導光部材６は、アクリル樹脂板等の透明板７からなっ
ている。The light guide member 6 disposed on the surface of the light guide plate 1 guides light emitted from each rising surface 2a of the stepped surface of the light guide plate and emits the light toward the surface. The optical member 6 is made of a transparent plate 7 such as an acrylic resin plate.

【００２２】すなわち、この導光部材６は、前記透明板
７の内部を前記導光板１の階段状面の段ピッチに対応す
るピッチで並ぶ複数の横長な導光領域Ａに導光面１０に
より区画されており、この透明板７の裏面に、前記各導
光領域Ａにそれぞれ対応させて、前記導光板１の階段状
面の各立上がり面２ａから出射する光を取り込んでその
光を対応する導光領域Ａに向けて屈折させる複数のプリ
ズム部８し、表面に、前記各導光領域Ａにそれぞれ対応
させて、前記導光領域Ａを導かれた光を集光方向に屈折
させて出射する複数の集光レンズ部９とが形成されてい
る。前記導光面１０は、前記各導光領域Ａの両側の境界
面に配置され、前記プリズム部８で屈折されて前記導光
領域Ａに導かれた光のうち、その導光領域Ａに対応する
集光レンズ部９の外側に向かう光を反射或は屈折させて
前記集光レンズ部９に導く反射及び／又は屈折導光面を
構成している。That is, the light guide member 6 is provided by the light guide surface 10 with a plurality of horizontally long light guide regions A arranged inside the transparent plate 7 at a pitch corresponding to the step pitch of the stepped surface of the light guide plate 1. The light emitted from each rising surface 2a of the stepped surface of the light guide plate 1 is taken into the rear surface of the transparent plate 7 corresponding to each of the light guide regions A to correspond to the light. A plurality of prism portions 8 for refracting the light toward the light guide region A are provided on the surface thereof so that the light guided through the light guide region A is refracted in the light condensing direction and emitted corresponding to each of the light guide regions A. And a plurality of condensing lens portions 9 are formed. The light guide surface 10 is disposed on a boundary surface on both sides of each of the light guide regions A, and corresponds to the light guide region A of the light refracted by the prism portion 8 and guided to the light guide region A. The reflection and / or refraction light guide surface is configured to reflect or refract light directed to the outside of the condensing lens unit 9 and guide the light to the condensing lens unit 9.

【００２３】なお、前記各プリズム部８は、断面が逆三
角形状で、導光部材６の全幅にわたる長さと前記導光領
域Ａの幅ｗとほぼ同じ幅を有する横長プリズム部であ
る。また前記各集光レンズ部９は、導光部材６の全幅に
わたる長さと前記プリズム部８の幅と同じ幅を有する横
長の凸レンズであり、そのレンズ光軸は導光部材６の垂
線に平行な方向にある。Each of the prism portions 8 is a horizontally long prism portion having an inverted triangular cross section and a length substantially equal to the entire width of the light guide member 6 and the width w of the light guide region A. Each of the condensing lens portions 9 is a horizontally long convex lens having the same length as the width of the prism portion 8 and the entire width of the light guide member 6, and the optical axis of the lens is parallel to the perpendicular of the light guide member 6. In the direction.

【００２４】この導光部材６の各導光面１０は、上記導
光板１の階段状面の幅方向に平行で、かつ導光部材６の
垂線に沿った面であり、これらの導光面１０は、前記各
プリズム部８の間の谷部のレベルよりも僅かに透明板７
内に入り込んだ位置から、前記各集光レンズ部９の間の
谷部のレベルよりも僅かに透明板７内に入り込んだ位置
にかけて垂直に形成されている。したがって、前記導光
領域Ａの高さｈは、実質的に前記導光面１０の高さと同
じ高さである。Each light guide surface 10 of the light guide member 6 is a surface parallel to the width direction of the stepped surface of the light guide plate 1 and along a perpendicular line of the light guide member 6. Reference numeral 10 denotes a transparent plate 7 slightly lower than the level of a valley between the prism portions 8.
It is formed vertically from the position where it enters into the inside of the transparent plate 7 to the position where it enters the transparent plate 7 slightly more than the level of the valley between the condenser lenses 9. Therefore, the height h of the light guide region A is substantially the same as the height of the light guide surface 10.

【００２５】また、この実施例では、前記導光領域Ａの
配列ピッチを上記導光板１の階段状面の段ピッチと同じ
にしており、したがって各導光領域Ａの幅ｗは、図示し
ない液晶表示パネルの画素幅とほぼ同じか、あるいは前
記画素幅の整数分の１の幅である。なお、前記導光領域
Ａは、その幅ｗよりも高さｈを大きくした縦長の領域で
あり、その幅ｗと高さｈの比は、少なくとも２倍以上に
選ぶのが望ましい。In this embodiment, the arrangement pitch of the light guide regions A is the same as the step pitch of the stepped surface of the light guide plate 1. Therefore, the width w of each light guide region A is equal to the width of a liquid crystal (not shown). It is almost the same as the pixel width of the display panel, or a width that is a fraction of the pixel width. The light guide region A is a vertically long region in which the height h is larger than the width w, and the ratio of the width w to the height h is desirably selected to be at least twice or more.

【００２６】さらに、この導光部材６では、前記透明板
７内の前記各導光領域Ａの境界部に、光の屈折率が前記
透明板７の屈折率よりも小さい物質からなる低屈折率層
１１を設け、この低屈折率層１１と前記透明板７との界
面を前記導光面１０としている。Further, in the light guide member 6, a low refractive index made of a substance having a refractive index of light smaller than that of the transparent plate 7 is provided at the boundary between the light guide regions A in the transparent plate 7. A layer 11 is provided, and an interface between the low refractive index layer 11 and the transparent plate 7 is the light guide surface 10.

【００２７】前記低屈折率層１１は、前記透明板７より
も屈折率が充分小さい物質の層であればよいが、この実
施例では、前記低屈折率層１１を、最も屈折率が小さい
空気層としている。The low-refractive-index layer 11 may be a layer made of a material having a refractive index sufficiently smaller than that of the transparent plate 7. In this embodiment, the low-refractive-index layer 11 is made of air having the smallest refractive index. And layers.

【００２８】前記導光部材６は、次のような製造方法で
製造することができる。すなわち、図２は前記導光部材
６の構成を示す分解断面図であり、前記導光部材６は、
第１の透明板７ａと第２の透明板７ｂとを組合わせて構
成される。The light guide member 6 can be manufactured by the following manufacturing method. That is, FIG. 2 is an exploded cross-sectional view illustrating the configuration of the light guide member 6, and the light guide member 6 includes:
It is configured by combining the first transparent plate 7a and the second transparent plate 7b.

【００２９】前記第１の透明板７ａは、一方の面に上記
プリズム部８を密に並べて配列形成し、他方の面に１つ
おきのプリズム部８にそれぞれ対応させて透明板全幅に
わたる縦長の凸部を形成したものであり、第２の透明板
７ｂは、一方の面に上記集光レンズ部９を密に並べて配
列形成し、他方の面に前記第１の透明板７ａの各凸部の
間のプリズム部８に対応する集光レンズ部９にそれぞれ
対応させて前記第１の透明板７ａの凸部と同じ形状の縦
長凸部を形成したものである。なお、この第１および第
２の透明板７ａ，７ｂは、いずれもアクリル樹脂等の透
明樹脂からなる成形品または切削加工品である。The first transparent plate 7a is formed in such a manner that the prism portions 8 are densely arranged and formed on one surface, and are formed on the other surface so as to correspond to every other prism portion 8, respectively. The second transparent plate 7b has the condensing lens portions 9 arranged and arranged densely on one surface and the respective convex portions of the first transparent plate 7a on the other surface. A vertically long convex portion having the same shape as the convex portion of the first transparent plate 7a is formed so as to correspond to the condenser lens portion 9 corresponding to the prism portion 8 therebetween. Each of the first and second transparent plates 7a and 7b is a molded product or a cut product made of a transparent resin such as an acrylic resin.

【００３０】これらの透明板７ａ，７ｂの凸部はそれぞ
れ、前記導光領域Ａの幅ｗおよび高さｈと同じ幅および
高さを有する縦長矩形状の断面をもった凸部であり、こ
れらの凸部の間の空間の幅ｗ′は、前記凸部の幅ｗより
も極く僅かに広く設定されている。The projections of the transparent plates 7a and 7b are each a projection having a vertically long rectangular cross section having the same width and height as the width w and the height h of the light guide region A, respectively. The width w 'of the space between the convex portions is set to be extremely slightly larger than the width w of the convex portions.

【００３１】そして、前記導光部材６は、前記第１の透
明板７ａと第２の透明板７ｂとを、一方の透明板の各凸
部を他方の透明板の凸部間の各空間に挿入して、それぞ
れの凸部の側面間の間隔ｄが全て均等になるようにして
組合わせ、各凸部の端面と各空間の底面とを透明な接着
剤（図示せず）で接着して製造する。The light guide member 6 includes the first transparent plate 7a and the second transparent plate 7b, each of the convex portions of one of the transparent plates being placed in each space between the convex portions of the other transparent plate. It inserts and combines so that the space | interval d between the side surfaces of each convex part may become all equal, and adhere | attaches the end surface of each convex part and the bottom face of each space with a transparent adhesive (not shown). To manufacture.

【００３２】このように第１の透明板７ａと第２の透明
板７ｂとを組み合わせると、各透明板７ａ，７ｂの各凸
部がそれぞれ導光領域Ａとなり、これらの凸部の側面間
の隙間が空気層（低屈折率層）１１となるとともに、こ
の空気層１１の両側面と前記凸部（透明板）との界面が
それぞれ、隣り合う一方の導光領域Ａの一側の導光面１
０と、他方の導光領域Ａの他側の導光面１０となり、ま
た裏面と表面に、各導光領域にそれぞれ対応する複数の
プリズム部８と複数の集光レンズ部９が配列した導光部
材６が得られる。When the first transparent plate 7a and the second transparent plate 7b are combined as described above, each convex portion of each of the transparent plates 7a and 7b becomes a light guide region A, and a side surface between these convex portions is formed. The gap becomes an air layer (low-refractive index layer) 11, and the interface between both side surfaces of the air layer 11 and the convex portion (transparent plate) is a light guide on one side of one adjacent light guide region A. Face 1
0, the light guide surface 10 on the other side of the other light guide region A, and a plurality of prism portions 8 and a plurality of condenser lens portions 9 corresponding to each light guide region on the back and front surfaces, respectively. The optical member 6 is obtained.

【００３３】なお、前記接着剤としては、できるだけ第
１および第２の透明板７ａ，７ｂの屈折率に近い屈折率
を有するものを用いるのが望ましく、前記透明板７ａ，
７ｂと接着剤層との屈折率が同じか、あるいは極く近い
屈折率であれば、前記凸部の端面と空間の底面との界面
での光の屈折がほとんど無い、良好な導光特性の導光部
材６を得ることができる。The adhesive preferably has a refractive index as close as possible to that of the first and second transparent plates 7a and 7b.
If the refractive index of 7b and the adhesive layer is the same or very close to each other, there is almost no refraction of light at the interface between the end surface of the convex portion and the bottom surface of the space. The light guide member 6 can be obtained.

【００３４】上記導光部材６は、図１に示したように、
その裏面の各プリズム部８の頂部を上記導光板１の階段
状面の各段部２の表面に当接させるとともに、これらの
プリズム部８の一側面を前記導光板１の階段状面の各立
上がり面２ａに近接対向させて導光板１の表面に配置さ
れている。The light guide member 6 is, as shown in FIG.
The top of each prism portion 8 on the back surface is brought into contact with the surface of each step portion 2 of the stepped surface of the light guide plate 1, and one side surface of these prism portions 8 is connected to each step surface of the light guide plate 1. The light guide plate 1 is arranged on the surface of the light guide plate 1 so as to be close to the rising surface 2a.

【００３５】この面光源装置は、導光板１の光取り込み
端面に対向させて配置した光源部３からの光を前記導光
板１とその表面に配置した導光部材６とにより導いて表
面方向に出射するものであり、前記光源部３からの光
は、図１に矢線で示したように導光板１にその端面から
取り込まれて導光板１内を導かれ、階段状面となってい
る導光板表面の各立上がり面２ａから出射して、前記導
光部材６の裏面の各プリズム部８にそれぞれ取り込まれ
る。In this surface light source device, the light from the light source unit 3 arranged opposite to the light receiving end face of the light guide plate 1 is guided by the light guide plate 1 and the light guide member 6 arranged on the surface thereof, and is directed in the surface direction. The light emitted from the light source unit 3 is taken into the light guide plate 1 from its end face and guided through the light guide plate 1 as shown by arrows in FIG. The light exits from each rising surface 2a of the light guide plate surface and is taken into each prism section 8 on the back surface of the light guide member 6, respectively.

【００３６】そして、前記各プリズム部８に取り込まれ
た光は、これらのプリズム部８で屈折されて導光部材６
の各導光領域Ａを導かれ、その表面の各集光レンズ部９
により集光方向に屈折されて出射する。The light introduced into each of the prism portions 8 is refracted by these prism portions 8 and is refracted by the light guide member 6.
Of each light guide region A, and each of the condenser lens portions 9 on the surface thereof.
The light is refracted in the light collecting direction and is emitted.

【００３７】この場合、前記導光板１にその端面から取
り込まれた光は、上述したように導光板１の表裏面で屈
折しながら導光板１内を導かれてその階段状面の各立上
がり面２ａからある程度の広がりをもって出射し、その
光が導光部材６の裏面の各プリズム部８に取り込まれ
て、このプリズム部８への入射角に応じた屈折角で屈折
されて導光領域Ａに導かれるため、導光部材６の各導光
領域Ａを表面方向に向かって進む光はある程度の広がり
をもった光である。In this case, the light taken into the light guide plate 1 from the end surface is guided inside the light guide plate 1 while being refracted on the front and back surfaces of the light guide plate 1 as described above, and each rising surface of the step-like surface is raised. 2a, the light is emitted with a certain degree of spread, the light is taken into each prism portion 8 on the back surface of the light guide member 6, and is refracted at a refraction angle corresponding to the angle of incidence on the prism portion 8 and enters the light guide region A. Since the light is guided, the light traveling toward the surface direction in each light guide region A of the light guide member 6 is light having a certain spread.

【００３８】すなわち、図３は上記面光源装置における
光の出射経路を示す導光部材６の一部分のハッチングを
省略した拡大断面図であり、導光板１の階段状面の各立
上がり面２ａから出射して導光部材６の裏面の各プリズ
ム部８に取り込まれた光は、図に矢線で示すように前記
プリズム部８への入射位置およびその入射角に応じて方
向に屈折され、ある程度の広がりをもって導光領域Ａを
表面方向に向かって進む。That is, FIG. 3 is an enlarged cross-sectional view of the surface light source device, showing a light emission path of the light guide member 6 with a part of the light guide member 6 being omitted from hatching. The light taken into each prism portion 8 on the back surface of the light guide member 6 is refracted in a direction according to the incident position and the incident angle on the prism portion 8 as shown by an arrow in the figure, and to a certain extent. The light guide region A travels toward the surface with spreading.

【００３９】そのため、前記導光領域Ａを表面方向に導
かれる光のうち、ある広がり範囲内の光は、導光領域Ａ
を直進してその導光領域Ａに対応する集光レンズ部９に
向かって進み、それよりも広がり範囲の大きい光は前記
集光レンズ部９の外側に向かって進むが、この集光レン
ズ部９の外側に向う光は導光領域Ａの両側の導光面１０
で反射或は屈折されて前記集光レンズ部９に導かれるた
め、前記プリズム部８から取り込んだ光のほとんどをロ
スすることなく集光レンズ部９に導くことができる。Therefore, of the light guided through the light guide region A in the surface direction, the light within a certain spread range is the light guide region A
Goes straight toward the condenser lens section 9 corresponding to the light guide area A, and light having a wider spread range proceeds toward the outside of the condenser lens section 9. 9 is directed to the light guide surfaces 10 on both sides of the light guide region A.
Then, the light is reflected or refracted and guided to the condenser lens section 9, so that most of the light taken in from the prism section 8 can be guided to the condenser lens section 9 without loss.

【００４０】そして、前記集光レンズ部９に入射した光
は、図３のように集光レンズ部９により集光方向に屈折
されて出射するが、前記導光領域Ａを直進して集光レン
ズ部９に入射した光、つまり集光レンズ部９のレンズ光
軸に沿った方向を中心とする広がり方向に沿って前記集
光レンズ部９に入射した光は、そのほとんどがほぼ正面
方向（集光レンズ部９のレンズ光軸に沿った方向）に出
射し、また前記導光面１０で反射或は屈折して前記集光
レンズ部９に入射した光、つまり前記レンズ光軸に沿っ
た方向を中心とする広がり方向とは異なる方向から集光
レンズ部９に入射した光は、そのほとんどが前記正面方
向に対してある程度の角度範囲の方向に向かって出射す
る。The light incident on the condenser lens section 9 is refracted by the condenser lens section 9 in the focusing direction as shown in FIG. Most of the light incident on the lens unit 9, that is, the light incident on the condenser lens unit 9 along a spreading direction centered on the direction along the lens optical axis of the condenser lens unit 9 is almost in the front direction ( (In the direction along the lens optical axis of the condensing lens unit 9), and the light reflected or refracted by the light guide surface 10 and incident on the condensing lens unit 9, ie, along the lens optical axis. Most of the light incident on the condenser lens section 9 from a direction different from the spreading direction centered on the direction is emitted in a direction within a certain angle range with respect to the front direction.

【００４１】したがって、この面光源装置によれば、そ
の表面から出射する光のほとんどを、周囲に放散するこ
となく正面方向および正面方向に対してある程度傾いた
角度範囲の方向に出射して、その範囲の出射光の輝度を
充分に高くすることができる。Therefore, according to the surface light source device, most of the light emitted from the surface is emitted in the front direction and in the direction of the angle range slightly inclined with respect to the front direction without radiating to the surroundings. The brightness of the emitted light in the range can be made sufficiently high.

【００４２】この面光源装置の光の出射範囲を、前記導
光領域Ａと導光面１０を有しない導光部材を用いた場合
と比べてみると、図４は、裏面と表面に前記導光部材６
と同様なプリズム部８′と集光レンズ部９′を形成した
だけの導光部材６′を上記導光板１の表面に配置したと
きの光の出射経路を示す図である。FIG. 4 shows that the light emission range of the surface light source device is compared with the case where a light guide member having neither the light guide region A nor the light guide surface 10 is used. Light member 6
FIG. 9 is a diagram showing a light exit path when a light guide member 6 ′ having only a prism portion 8 ′ and a condenser lens portion 9 ′ similar to the above is arranged on the surface of the light guide plate 1.

【００４３】なお、この導光部材６′は、その裏面のプ
リズム部８′から表面の集光レンズ部９′までの距離
（導光部材の厚さ）を小さくして前記プリズム部８′で
屈折された光の広がり範囲を規制し、前記プリズム部
８′により表面方向に向けて屈折された光を、そのプリ
ズム部８′に対応する集光レンズ部９′から出射させる
ようにしたものである。In this light guide member 6 ', the distance (thickness of the light guide member) from the prism portion 8' on the back surface to the converging lens portion 9 'on the front surface is reduced so that the prism portion 8' The spread range of the refracted light is regulated, and the light refracted toward the surface direction by the prism portion 8 'is emitted from the condenser lens portion 9' corresponding to the prism portion 8 '. is there.

【００４４】このような導光部材６′を用いた場合は、
その裏面のプリズム部８′により表面方向に向けて屈折
された光が図４に矢線で示した集光レンズ部９′のレン
ズ光軸に沿った方向を中心とする広がり方向に沿って前
記集光レンズ部９′に入射し、その光のほとんどがほぼ
正面方向に出射するため、光の出射角範囲が狭く、した
がって正面輝度は高いが、斜め方向から観察すると輝度
が極端に低くなる。When such a light guide member 6 'is used,
The light refracted toward the front surface by the prism portion 8 'on the rear surface is spread along the spreading direction centered on the direction along the lens optical axis of the condenser lens portion 9' shown by an arrow in FIG. Since the light is incident on the condenser lens portion 9 'and most of the light is emitted almost in the front direction, the emission angle range of the light is narrow. Therefore, the front luminance is high, but the luminance becomes extremely low when obliquely observed.

【００４５】これに対して、上記実施例の面光源装置で
は、上述したように、導光部材６の裏面のプリズム部８
で屈折されて導光領域Ａを表面方向に導かれる光のう
ち、導光領域Ａを直進して集光レンズ部９に入射した光
がほぼ正面方向に出射し、前記導光領域Ａの両側の導光
面１０で反射或は屈折されて前記集光レンズ部９に入射
した光が前記正面方向に対してある程度の角度範囲の方
向に向かって斜め方向に出射するため、正面輝度だけで
なく、正面方向に対してある程度傾いた角度範囲から観
察したときの輝度も高い。On the other hand, in the surface light source device of the above embodiment, as described above, the prism portion 8 on the back surface of the light guide member 6 is provided.
Of the light refracted by the light guide region A and guided to the surface direction, the light that travels straight through the light guide region A and enters the condenser lens portion 9 is emitted substantially in the front direction, and both sides of the light guide region A The light reflected or refracted by the light guide surface 10 and incident on the condenser lens portion 9 is emitted obliquely toward a direction within a certain angle range with respect to the front direction. Also, the brightness when viewed from an angle range inclined to some extent with respect to the front direction is high.

【００４６】また、前記集光レンズ部９に入射する光
は、導光領域Ａを直進してきた光も、前記導光面１０で
反射或は屈折されて集光レンズ部９に導かれた光も、あ
る広がりをもった光であり、その光が集光レンズ部９へ
の入射角に応じて屈折されて出射するため、前記正面方
向および正面方向に対してある程度傾いた角度範囲の方
向に出射する光の輝度分布もほぼ均一である。The light incident on the condensing lens portion 9 is also the light that has traveled straight through the light guide region A and is reflected or refracted by the light guiding surface 10 and guided to the condensing lens portion 9. Is also a light having a certain spread, and the light is refracted and emitted in accordance with the incident angle to the condenser lens unit 9, so that the light is directed in the front direction and in a direction of an angle range slightly inclined with respect to the front direction. The luminance distribution of the emitted light is also substantially uniform.

【００４７】そして、前記集光レンズ９からの光の出射
角範囲は、この集光レンズ部９のレンズ面の曲率を選ぶ
ことによって任意に設定できるため、この面光源装置に
よれば、正面方向を含む所望の角度範囲の輝度を高くす
るとともに、その輝度分布もほぼ均一にすることができ
る。The exit angle range of the light from the condenser lens 9 can be arbitrarily set by selecting the curvature of the lens surface of the condenser lens section 9. Therefore, according to the surface light source device, , And the luminance distribution can be made substantially uniform.

【００４８】そのため、上記面光源装置は、液晶表示装
置のバックライトとして好適であり、この面光源装置を
バックライトに用いれば、前記液晶表示装置に、正面輝
度が高く、しかも視野角も広い良好な表示を行なわせる
ことができる。Therefore, the above-mentioned surface light source device is suitable as a backlight of a liquid crystal display device. If this surface light source device is used as a backlight, the liquid crystal display device has a high front luminance and a wide viewing angle. Display can be performed.

【００４９】また、上記面光源装置では、前記導光部材
６を構成する透明板７内の各導光領域Ａの境界部に、光
の屈折率が前記透明板７の屈折率よりも小さい物質から
なる低屈折率層１１を設け、この低屈折率層１１と前記
透明板７との界面を、前記導光領域Ａを表面方向に導か
れる光のうちの集光レンズ部９の外側に向かう光を反射
させて前記集光レンズ部９に導く導光面１０としている
ため、前記透明板７内に前記低屈折率層１１を設けるだ
けで、前記導光領域Ａとその両側の導光面１０を同時に
形成することができるし、さらに上記実施例のように前
記低屈折率層１１を空気層とすれば、前記導光部材６を
上述した製造方法で容易に製造することができる。In the above surface light source device, a material having a refractive index of light smaller than the refractive index of the transparent plate 7 is provided at a boundary portion of each light guide region A in the transparent plate 7 constituting the light guide member 6. Is provided, and the interface between the low-refractive-index layer 11 and the transparent plate 7 is directed toward the outside of the converging lens portion 9 of the light guided through the light-guiding region A toward the surface. Since the light guide surface 10 reflects the light and guides the light to the condenser lens portion 9, the light guide region A and the light guide surfaces on both sides thereof are provided only by providing the low refractive index layer 11 in the transparent plate 7. 10 can be formed simultaneously, and if the low refractive index layer 11 is an air layer as in the above embodiment, the light guide member 6 can be easily manufactured by the above-described manufacturing method.

【００５０】なお、前記導光部材６の導光面１０は、上
記実施例に限らず、例えば各導光領域Ａの境界部に反射
膜を設けて形成してもよく、その場合は、上述した前記
導光部材６の製造方法において各透明板７ａ，７ｂの凸
部の両側面に金属膜を蒸着またはメッキして前記反射膜
を形成してもよいし、また、前記導光部材６を樹脂成形
により形成し、その成形時に前記反射膜をインサートし
てもよい。The light guide surface 10 of the light guide member 6 is not limited to the above embodiment, and may be formed, for example, by providing a reflection film at the boundary of each light guide region A. In the method of manufacturing the light guide member 6 described above, the reflective film may be formed by depositing or plating a metal film on both side surfaces of the convex portion of each of the transparent plates 7a and 7b. It may be formed by resin molding, and the reflective film may be inserted during the molding.

【００５１】また、上記実施例では、導光板１の階段状
面の段ピッチと前記導光部材６の導光領域Ａのピッチと
を同じにしたが、前記導光板１の階段状面の段ピッチを
導光部材６の導光領域Ａのピッチの整数分の１に小さく
し、前記階段状面の複数の立上がり面２ａからの出射光
を前記導光部材６の１つのプリズム部８に取り込むよう
にしてもよい。In the above embodiment, the step pitch of the stepped surface of the light guide plate 1 and the pitch of the light guide region A of the light guide member 6 are the same. The pitch is reduced to an integral fraction of the pitch of the light guide region A of the light guide member 6, and light emitted from the plurality of rising surfaces 2 a of the stepped surface is taken into one prism portion 8 of the light guide member 6. You may do so.

【００５２】さらに上記実施例では、導光板１として、
その表面を一端側から他端側に向かって低くなる階段状
面とし、前記一端側の端面を光取り込み端面としたもの
を用いたが、導光板は、その中間部から一端側と他端側
とをそれぞれその端部から前記中間部に向かって低くな
る階段状面とし、両端面をそれぞれ光取り込み端面とし
たもの、すなわち、図１に示した形状の導光板１とそれ
と左右対称な形状の導光板とをその先端同士を付き合わ
せた状態で配置した形状のものであってもよく、このよ
うな形状の導光板を用いれば、その両端面にそれぞれ対
向させて光源部３を配置して、より高輝度の光を出射す
ることができる。Further, in the above embodiment, the light guide plate 1 is
The surface is a step-like surface that becomes lower from one end side to the other end side, and the end face on the one end side is used as a light capturing end face. Is a step-like surface that becomes lower from its end toward the intermediate portion, and both end surfaces are light-intake end surfaces, that is, a light guide plate 1 having the shape shown in FIG. The light guide plate and the light guide plate may be arranged in such a state that their tips are attached to each other. If a light guide plate having such a shape is used, the light source unit 3 is arranged to face both end surfaces thereof. Thus, light with higher luminance can be emitted.

【００５３】なお、この場合は、導光板の一端面から取
り込まれた光がその側の階段状面の各立上がり面から出
射し、他端面から取り込まれた光がその側の階段状面の
各立上がり面から出射するため、導光部材６の一半分の
領域の各プリズム部８の光の取り込み方向と、他半分の
領域の各プリズム部８の光の取り込み方向とが逆になる
が、全てのプリズム部８を左右対称な形状とするか、あ
るいは前記一半分の領域の各プリズム部８の形状と他半
分の領域の各プリズム部８の形状とをそれぞれの光取り
込み方向に応じて設計すれば、いずれの領域のプリズム
部８に取り込んだ光もそのプリズム部８に対応する導光
領域Ａに向けて屈折させることができる。In this case, the light taken in from one end face of the light guide plate is emitted from each rising face of the stepped face on that side, and the light taken in from the other end face is taken out of each stepped face on that side. Since the light is emitted from the rising surface, the light capturing direction of each prism portion 8 in one half of the light guide member 6 is opposite to the light capturing direction of each prism portion 8 in the other half region. Or the shape of each prism portion 8 in the one-half region and the shape of each prism portion 8 in the other half region are designed in accordance with the respective light capturing directions. Thus, the light taken into the prism portion 8 in any region can be refracted toward the light guide region A corresponding to the prism portion 8.

【００５４】また、上記実施例では、導光部材６の表面
の各集光レンズ部９を凸レンズとしたが、この集光レン
ズ部９はフレネルレンズであってもよく、さらに光源部
３は、蛍光ランプ４を用いるものに限らず、例えば複数
のＬＥＤ（発光ダイオード）を整列させたＬＥＤアレイ
等を用いるものでもよい。なお、この発明は、液晶表示
装置のバックライトに用いる面光源装置に限らず、各種
用途の面光源装置に広く適用することができる。In the above embodiment, each of the condenser lenses 9 on the surface of the light guide member 6 is a convex lens. However, the condenser lenses 9 may be Fresnel lenses. The present invention is not limited to the one using the fluorescent lamp 4, but may be one using an LED array in which a plurality of LEDs (light emitting diodes) are arranged. The present invention is not limited to the surface light source device used for the backlight of the liquid crystal display device, and can be widely applied to the surface light source device for various uses.

【００５５】[0055]

【発明の効果】この発明の面光源装置は、表面が階段状
面となっており、端面から光を取り込んでその光を前記
階段状面の各立上がり面から出射する導光板の表面に、
内部を複数の導光領域に区画する複数の導光面と、裏面
に前記導光板の階段状面の各立上がり面から出射する光
を取り込んでその光を対応する導光領域に向けて屈折さ
せる複数のプリズムと、表面に前記導光領域を導かれた
光を集光方向に屈折させて出射する複数の集光レンズ部
とが形成され前記プリズム部で屈折されて前記導光領域
に導かれた光のうち、その導光領域に対応する集光レン
ズ部の外側に向かう光を前記導光面により反射或は屈折
させて前記集光レンズ部に導く透明板からなる導光部材
を配置することにより、前記導光板の光取り込み端面に
対向させて配置した光源部からの光を前記導光板と導光
部材とによって導いて表面方向に出射するようにしたも
のであるから、その表面から出射する光のほとんどを、
周囲に放散させることなく正面方向を含む所望の角度範
囲の方向に出射して、その範囲の輝度を充分に高くする
ことができるとともに、その輝度分布もほぼ均一にする
ことができる。According to the surface light source device of the present invention, the surface has a stepped surface, and the surface of the light guide plate which takes in light from the end surface and emits the light from each rising surface of the stepped surface is provided.
A plurality of light guide surfaces that divide the interior into a plurality of light guide regions, and light emitted from each rising surface of the stepped surface of the light guide plate is taken into the back surface and the light is refracted toward the corresponding light guide region. A plurality of prisms and a plurality of condensing lens portions that refract light guided to the light guide region in the direction of light condensing on the surface and emit the light are formed, and are refracted by the prism portion and guided to the light guide region. The light guide member made of a transparent plate that reflects or refracts the light directed to the outside of the condensing lens portion corresponding to the light guiding region out of the collected light and guides the light to the condensing lens portion is disposed. With this configuration, light from the light source unit disposed opposite to the light capturing end face of the light guide plate is guided by the light guide plate and the light guide member and emitted toward the surface, and is emitted from the surface. Most of the light
The light is emitted in the direction of a desired angle range including the front direction without being diffused to the surroundings, and the brightness in the range can be sufficiently increased, and the brightness distribution can be made substantially uniform.

【００５６】また、この発明の面光源装置において、前
記導光部材を構成する透明板内の各導光領域の境界部
に、光の屈折率が前記透明板の屈折率よりも小さい物質
からなる低屈折率層を設け、この低屈折率層と前記透明
板との界面を、前記導光領域を表面方向に導かれる光の
うちの集光レンズ部の外側に向かう光を屈折させて前記
集光レンズ部に導く導光面とすれば、前記透明板内に前
記低屈折率層を設けるだけで、前記導光領域とその両側
の導光面を同時に形成することができるし、さらに前記
低屈折率層を空気層とすれば、前記導光部材を容易に製
造することができる。Further, in the surface light source device according to the present invention, the boundary portion between the light guide regions in the transparent plate constituting the light guide member is made of a substance having a refractive index of light smaller than that of the transparent plate. A low-refractive-index layer is provided, and the interface between the low-refractive-index layer and the transparent plate is refracted by the light directed to the outside of the converging lens portion of the light guided through the light guide region toward the surface. If the light guide surface guides to the optical lens portion, the light guide region and the light guide surfaces on both sides thereof can be simultaneously formed only by providing the low refractive index layer in the transparent plate, and If the refractive index layer is an air layer, the light guide member can be easily manufactured.

【図面の簡単な説明】[Brief description of the drawings]

【図１】この発明の一実施例による面光源装置のハッチ
ングを省略した断面図。FIG. 1 is a cross-sectional view of a surface light source device according to an embodiment of the present invention, in which hatching is omitted.

【図２】前記面光源装置に用いた導光部材の構成を示す
分解断面図。FIG. 2 is an exploded cross-sectional view showing a configuration of a light guide member used in the surface light source device.

【図３】前記面光源装置における光の出射経路を示す導
光部材の一部分のハッチングを省略した拡大断面図。FIG. 3 is an enlarged cross-sectional view showing a light exit path of the surface light source device, in which a part of a light guide member is omitted from hatching.

【図４】導光領域と導光面を有しない導光部材を用いた
場合の光の出射経路を示す図。FIG. 4 is a diagram showing a light emission path when a light guide member having no light guide region and a light guide surface is used.

【符号の説明】 １…導光板 ２…段部 ２ａ…立上がり面 ３…光源部 ６…導光部材 ７…透明板 Ａ…導光領域 ８…プリズム部 ９…集光レンズ部 １０…導光面 １１…低屈折率層（空気層）[Description of Symbols] 1 ... Light guide plate 2 ... Stepped portion 2a ... Rising surface 3 ... Light source portion 6 ... Light guide member 7 ... Transparent plate A ... Light guide region 8 ... Prism portion 9 ... Condensing lens portion 10 ... Light guide surface 11 Low refractive index layer (air layer)

Claims (3)

【特許請求の範囲】[Claims] 【請求項１】表面が階段状面となっており端面から光を
取り込んでその光を前記階段状面の各立上がり面から出
射する導光板と、 前記導光板の光取り込み端面に対向させて配置された光
源部と、 前記導光板の表面に配置され、その階段状面の各立上が
り面から出射する光を導いて表面方向に出射する導光部
材とを備え、 前記導光部材は、内部を前記導光板の階段状面の段ピッ
チに対応するピッチで複数の導光領域に区画する複数の
導光面と、裏面に前記各導光領域にそれぞれ対応させて
前記導光板の階段状面の各立上がり面から出射する光を
取り込んでその光を対応する導光領域に向けて屈折させ
る複数のプリズム部と、表面に前記各導光領域にそれぞ
れ対応させて前記導光領域を導かれた光を集光方向に向
けてて出射させる複数の集光レンズ部とが形成され、前
記プリズム部で屈折されて前記導光領域に導かれた光の
うち、その導光領域に対応する集光レンズ部の外側に向
かう光を前記導光面により前記集光レンズ部に導く透明
板からなっていることを特徴とする面光源装置。A light guide plate for receiving light from an end surface and emitting the light from each rising surface of the step surface; and a light guide plate disposed opposite to a light receiving end surface of the light guide plate. And a light guide member disposed on the surface of the light guide plate and guiding light emitted from each rising surface of the stepped surface and emitting the light toward the surface direction. A plurality of light guide surfaces that are divided into a plurality of light guide regions at a pitch corresponding to the step pitch of the step surface of the light guide plate, and a step surface of the light guide plate corresponding to each of the light guide regions on the back surface. A plurality of prism portions that take in light emitted from each rising surface and refract the light toward the corresponding light guide region, and light guided through the light guide region corresponding to each of the light guide regions on the surface. Multiple light-collecting lasers And the light guided by the prism portion and guided to the light guide region is directed toward the outside of the condensing lens portion corresponding to the light guide region by the light guide surface. A surface light source device comprising a transparent plate leading to an optical lens portion. 【請求項２】前記透明板内の前記各導光領域の反射面
は、前記各導光領域の境界部に形成された、光の屈折率
が前記透明板の屈折率よりも小さい物質からなる低屈折
率層と前記透明板との界面からなることを特徴とする請
求項１に記載の面光源装置。2. The reflection surface of each of the light guide regions in the transparent plate is formed of a substance formed at a boundary between the light guide regions and having a refractive index of light smaller than that of the transparent plate. The surface light source device according to claim 1, comprising an interface between a low refractive index layer and the transparent plate. 【請求項３】前記低屈折率層は空気層であることを特徴
とする請求項２に記載の面光源装置。3. The surface light source device according to claim 2, wherein the low refractive index layer is an air layer.
JP9098894A 1996-06-21 1997-04-16 Surface light source device Pending JPH10289604A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
JP9098894A JPH10289604A (en) 1997-04-16 1997-04-16 Surface light source device
US08/878,412 US5914760A (en) 1996-06-21 1997-06-18 Surface light source device and liquid crystal display device using the same
KR1019970026082A KR100237405B1 (en) 1996-06-21 1997-06-20 Surface light source device and lcd device using the same
EP97110147A EP0814300A1 (en) 1996-06-21 1997-06-20 Surface light source device and liquid crystal display device using the same
TW086108626A TW346546B (en) 1996-06-21 1997-06-20 Surface light source device and liquid crystal display device using the same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP9098894A JPH10289604A (en) 1997-04-16 1997-04-16 Surface light source device

Publications (1)

Publication Number Publication Date
JPH10289604A true JPH10289604A (en) 1998-10-27

Family

ID=14231847

Family Applications (1)

Application Number Title Priority Date Filing Date
JP9098894A Pending JPH10289604A (en) 1996-06-21 1997-04-16 Surface light source device

Country Status (1)

Country Link
JP (1) JPH10289604A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020507128A (en) * 2017-01-04 2020-03-05 スリーエム イノベイティブ プロパティズ カンパニー Light control film for display assembly

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020507128A (en) * 2017-01-04 2020-03-05 スリーエム イノベイティブ プロパティズ カンパニー Light control film for display assembly

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