JP2011003506A - Surface light source - Google Patents

Surface light source Download PDF

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JP2011003506A
JP2011003506A JP2009147845A JP2009147845A JP2011003506A JP 2011003506 A JP2011003506 A JP 2011003506A JP 2009147845 A JP2009147845 A JP 2009147845A JP 2009147845 A JP2009147845 A JP 2009147845A JP 2011003506 A JP2011003506 A JP 2011003506A
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sheet
frame
light
guide plate
light guide
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Hideaki Watanabe
英章 渡辺
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Casio Computer Co Ltd
カシオ計算機株式会社
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Abstract

PROBLEM TO BE SOLVED: To provide a surface light source capable of irradiating a light having a uniform luminance distribution, having no luminance unevenness.SOLUTION: A surface light source includes a frame 1, having a space opening to the outside; a light guide plate 10 including an incident end face 11, permitting a light to enter and an outgoing face 12 for outputting the light incident from the incident end face 11, while the light guide plate is arranged in the space inside the frame 1 so that the outgoing face 12 faces an opening face of the space; light-emitting elements 14 arranged in the space inside the frame 1 so as to face the incident end face of the light guide plate 10; and an optical sheet 21 arranged on the outgoing face side of the light guide plate 10. The frame 1 includes a sheet-mounting surface 3, formed in an end face of a frame 2, surrounding a space where the light guide plate 10 and the light-emitting elements 14 are arranged. In the optical sheet 21, a peripheral part on the entire circumference thereof overhangs the circumference of the light guide plate 10, and all of each side or sides other than a side corresponding to the arrangement side of the light-emitting elements 14 have a shape formed to be a straight line side over the entire length of the sides. The optical sheet is arranged so that the peripheral parts are mounted on the sheet-mounting face 3 of the frame 1.

Description

この発明は、面光源に関する。   The present invention relates to a surface light source.
例えば液晶表示パネルの背後に配置される面光源として、枠形状に形成されたフレーム内の空間に、1つの端面に光を入射させる入射端面が形成され、2つの板面の一方に前記入射端面から入射した光を出射させる出射面が形成された導光板を配置すると共に、前記フレーム内の空間に、前記導光板の入射端面に対向させて発光素子を配置し、さらに前記導光板の出射面側に、プリズムシート等の光学シートを配置したものがある。   For example, as a surface light source disposed behind a liquid crystal display panel, an incident end face for allowing light to enter one end face is formed in a frame-shaped space, and the incident end face is formed on one of two plate faces. A light guide plate formed with an emission surface for emitting light incident from the light source, and a light emitting element arranged in the space in the frame so as to face the incident end surface of the light guide plate, and further, the light emission surface of the light guide plate There is an optical sheet such as a prism sheet disposed on the side.
このような面光源において、前記光学シートは、その周縁部の複数箇所に耳状の凸部を形成した形状に形成されており、前記フレーム内の空間に、前記耳状の凸部を前記フレームに支持させて配置されている(特許文献1参照)。   In such a surface light source, the optical sheet is formed in a shape in which an ear-shaped convex portion is formed at a plurality of locations on the peripheral portion thereof, and the ear-shaped convex portion is formed in the space in the frame. (See Patent Document 1).
特開2003−315793号公報JP 2003-315793 A
しかし、上記従来の面光源は、前記導光板の出射面から出射し、さらに前記光学シートを透過して出射する照射光に輝度むらを生じるという問題をもっている。   However, the conventional surface light source has a problem in that unevenness in luminance occurs in irradiation light that is emitted from the emission surface of the light guide plate and is further transmitted through the optical sheet.
この発明は、輝度むらの無い均一な輝度分布の光を照射することができる面光源を提供することを目的としたものである。   An object of the present invention is to provide a surface light source capable of irradiating light having a uniform luminance distribution with no luminance unevenness.
請求項1に記載の発明は、外部に開口した空間を有するフレームと、光を入射させる入射端面と前記入射端面から入射した光を出射させる出射面とを有し、前記フレーム内の空間に、前記出射面を前記空間の開口面に対向させて配置された導光板と、前記フレーム内の空間に、前記導光板の入射端面に対向させて配置された発光素子と、前記導光板の出射面側に配置された光学シートと、を備えた面光源において、
前記フレームは、前記導光板及び前記発光素子の配置空間を囲む枠状部の端面に形成されたシート載置面を有し、
前記光学シートは、周縁部が全周にわたって前記導光板の周囲に張出し、且つ各辺の全てまたは前記発光素子の配置側の辺に対向する一辺とこれに隣接する二辺が、これらの辺の全長にわたって直線辺に形成された形状を有し、前記周縁部を前記フレームの前記シート載置面上に載置して配置されていることを特徴とする。
The invention according to claim 1 includes a frame having a space opened to the outside, an incident end face for allowing light to enter, and an exit face for emitting light incident from the incident end face, and the space in the frame includes: A light guide plate disposed so that the exit surface faces the opening surface of the space, a light emitting element disposed in the space in the frame so as to face the incident end surface of the light guide plate, and the exit surface of the light guide plate In a surface light source comprising an optical sheet disposed on the side,
The frame has a sheet placement surface formed on an end surface of a frame-shaped portion that surrounds an arrangement space of the light guide plate and the light emitting element,
The optical sheet has a peripheral edge that extends around the entire circumference of the light guide plate, and one side that faces all of the sides or the side on which the light emitting element is disposed and two sides that are adjacent to these sides are It has a shape formed on a straight side over its entire length, and is arranged with the peripheral edge placed on the sheet placement surface of the frame.
請求項2に記載の発明は、前記請求項1に記載の面光源において、前記フレームの枠状部は矩形枠形状に形成され、前記シート載置面は前記枠状部の端面の全周にわたって形成されており、前記導光板は、前記フレームの前記枠状部により囲まれた空間に収容される矩形形状に形成され、前記光学シートは、その周縁部が前記シート載置面上に重なる矩形形状に形成されていることを特徴とする。   According to a second aspect of the present invention, in the surface light source of the first aspect, the frame-shaped portion of the frame is formed in a rectangular frame shape, and the sheet placement surface extends over the entire circumference of the end surface of the frame-shaped portion. The light guide plate is formed in a rectangular shape that is accommodated in a space surrounded by the frame-shaped portion of the frame, and the optical sheet has a rectangular shape with a peripheral edge portion overlapping the sheet placement surface. It is formed in a shape.
請求項3に記載の発明は、前記請求項1または2に記載の面光源において、前記フレームは、前記導光板及び前記発光素子の配置空間を囲む枠状部と、前記枠状部の端面上に前記シート載置面を囲んで突設された側壁部と、前記側壁部のうちの少なくとも互いに反対側の2つの側壁部の内面の前記シート載置面上の部分を、その全長にわたって前記シート載置面の延長方向に凹入させて形成されたシート差込み溝とを有しており、前記光学シートは、その少なくとも互いに反対側の2つの辺の縁部の先端を前記シート差込み溝に差込んで前記シート載置面上に配置されていることを特徴とする。   According to a third aspect of the present invention, in the surface light source according to the first or second aspect, the frame includes a frame-shaped portion surrounding an arrangement space of the light guide plate and the light-emitting element, and an end surface of the frame-shaped portion. A portion of the side wall portion projecting around the sheet placement surface and the inner surface of at least two side wall portions opposite to each other of the side wall portions on the sheet placement surface over the entire length thereof. A sheet insertion groove formed by being recessed in the extending direction of the mounting surface, and the optical sheet includes at least the ends of the edges of the two sides opposite to each other and the sheet insertion groove. And arranged on the sheet placement surface.
請求項4に記載の発明は、前記請求項3に記載の面光源において、前記光学シートの周縁部の外面にその周縁部の全周にわたって、前記フレームの枠状部の内周面と前記導光板の外周縁との間の領域を覆う形状に形成された遮光膜が配置され、前記光学シート及び前記遮光膜は、その少なくとも互いに反対側の2つの辺の縁部の先端をそれぞれ前記シート差込み溝に差込んで前記シート載置面上に配置されていることを特徴とする。   According to a fourth aspect of the present invention, there is provided the surface light source according to the third aspect, wherein the outer peripheral surface of the peripheral edge of the optical sheet and the inner peripheral surface of the frame-shaped portion of the frame are guided over the entire periphery of the peripheral portion. A light-shielding film formed in a shape covering a region between the outer peripheral edge of the optical plate is disposed, and the optical sheet and the light-shielding film are inserted into the sheet at the ends of the edges of at least two sides opposite to each other. The sheet is inserted into a groove and disposed on the sheet placement surface.
請求項5に記載の発明は、前記請求項1または2に記載の面光源において、前記フレームは、前記導光板及び前記発光素子の配置空間を囲む枠状部と、前記枠状部の端面上に前記シート載置面を囲んで突設された側壁部とを有しており、前記光学シートは、その少なくとも互いに反対側の2つの辺の縁部の先端位置を前記側壁部の内面により位置決めして前記シート載置面上に配置されていることを特徴とする。   According to a fifth aspect of the present invention, in the surface light source according to the first or second aspect, the frame includes a frame-shaped portion surrounding an arrangement space of the light guide plate and the light-emitting element, and an end surface of the frame-shaped portion. And a side wall portion projecting around the sheet mounting surface, and the optical sheet positions at least the tip positions of the edges of two sides opposite to each other by the inner surface of the side wall portion. And it is arrange | positioned on the said sheet | seat mounting surface, It is characterized by the above-mentioned.
請求項6に記載の発明は、前記請求項1または2に記載の面光源において、前記フレームの前記シート載置面は、前記フレームの枠状部の端面の内周側の部分をその全周にわたって凹入させて形成されており、前記光学シートは、その少なくとも互いに反対側の2つの辺の縁部の先端位置を前記凹入したシート載置面の外側の立上がり面により位置決めして前記シート載置面上に配置されていることを特徴とする。   According to a sixth aspect of the present invention, in the surface light source according to the first or second aspect, the sheet placement surface of the frame has a portion on the inner peripheral side of the end surface of the frame-shaped portion of the frame. The optical sheet is formed by positioning the leading end positions of at least the edges of two sides opposite to each other by a rising surface outside the recessed sheet placement surface. It is arrange | positioned on the mounting surface, It is characterized by the above-mentioned.
請求項7に記載の発明は、前記請求項1〜3及び請求項5〜6の何れか一つに記載の面光源において、前記光学シートの周縁部の外面に、前記フレームの枠状部の内周面と前記導光板の外周縁との間の領域を覆う形状に形成された遮光膜が配置されていることを特徴とする。   According to a seventh aspect of the present invention, in the surface light source according to any one of the first to third aspects and the fifth to sixth aspects, the frame-shaped portion of the frame is formed on the outer surface of the peripheral portion of the optical sheet. The light-shielding film formed in the shape which covers the area | region between an internal peripheral surface and the outer periphery of the said light-guide plate is arrange | positioned, It is characterized by the above-mentioned.
請求項8に記載の発明は、前記請求項7に記載の面光源において、前記遮光膜は、前記光学シートの周縁部の全周にわって配置されていることを特徴とする。   According to an eighth aspect of the present invention, in the surface light source according to the seventh aspect, the light shielding film is arranged over the entire circumference of the peripheral edge of the optical sheet.
請求項9に記載の発明は、前記請求項7に記載の面光源において、前記遮光膜は、前記光学シートの周縁部のうちの前記発光素子の配置側に対応する縁部に配置されていることを特徴とする。   According to a ninth aspect of the present invention, in the surface light source according to the seventh aspect, the light shielding film is disposed at an edge portion corresponding to the light emitting element arrangement side in the peripheral portion of the optical sheet. It is characterized by that.
請求項10に記載の発明は、前記請求項1〜9の何れか一つに記載の面光源において、前記光学シートは、一方の面が平坦面に形成され、他方の面に複数の微細なプリズム部が配列形成されたプリズムシートであることを特徴とする。   A tenth aspect of the present invention is the surface light source according to any one of the first to ninth aspects, wherein the optical sheet has a flat surface on one surface and a plurality of fine surfaces on the other surface. It is a prism sheet in which prism portions are arranged and formed.
請求項11に記載の発明は、前記請求項10に記載の面光源において、前記導光板の出射面側に、前記導光板の外形と略同じ形状に形成された第1プリズムシートと、周縁部が全周にわたって前記導光板の周囲に張出し、且つ各辺の全てまたは前記発光素子の配置側に対向する一辺とこれに隣接する二辺がそれぞれ、これらの辺の全長にわたって直線辺に形成された形状の第2プリズムシートとが、それぞれの平坦面を前記導光板側に向けて配置され、前記第1プリズムシートは、前記導光板の出射面上に貼付けられ、前記第2プリズムシートが、前記周縁部を前記フレームの前記シート載置面上に載置して配置されていることを特徴とする。   The invention according to claim 11 is the surface light source according to claim 10, wherein a first prism sheet formed on the light exit surface side of the light guide plate and having a shape substantially the same as the outer shape of the light guide plate, and a peripheral portion Projecting around the light guide plate over the entire circumference, and all sides or one side facing the light emitting element arrangement side and two sides adjacent to each side are formed on straight sides over the entire length of these sides. Shaped second prism sheets are arranged with their respective flat surfaces facing the light guide plate side, the first prism sheet is affixed on the exit surface of the light guide plate, and the second prism sheet is The peripheral portion is placed on the sheet placement surface of the frame, and is arranged.
請求項12に記載の発明は、前記請求項11に記載の面光源において、前記導光板の出射面と前記第1プリズムシートとの間に、前記第1プリズムシートと略同じ形状に形成された拡散シートが配置され、前記第1プリズムシートは、前記拡散シートを介して前記導光板の出射面上に貼付けられていることを特徴とする。   According to a twelfth aspect of the present invention, in the surface light source according to the eleventh aspect, the light source plate is formed between the emission surface of the light guide plate and the first prism sheet in substantially the same shape as the first prism sheet. A diffusion sheet is disposed, and the first prism sheet is affixed on an output surface of the light guide plate via the diffusion sheet.
この発明の面光源によれば、輝度むらの無い均一な輝度分布の光を照射することができる。   According to the surface light source of the present invention, it is possible to irradiate light having a uniform luminance distribution without luminance unevenness.
この発明の第1実施例の面光源の平面図。The top view of the surface light source of 1st Example of this invention. 第1実施例の面光源の分解斜視図。The disassembled perspective view of the surface light source of 1st Example. 第1実施例の面光源の図1のIII−III矢視線に沿った拡大断面図。The expanded sectional view along the III-III arrow line of FIG. 1 of the surface light source of 1st Example. この発明の第2実施例の面光源の平面図。The top view of the surface light source of 2nd Example of this invention. この発明の第3実施例の面光源の平面図。The top view of the surface light source of 3rd Example of this invention. この発明の第4実施例の面光源におけるフレームと光学シートの一部分の断面図。Sectional drawing of the flame | frame and a part of optical sheet in the surface light source of 4th Example of this invention. この発明の第5実施例の面光源におけるフレームと光学シートの一部分の断面図。Sectional drawing of the flame | frame and a part of optical sheet in the surface light source of 5th Example of this invention. この発明の第6実施例の面光源におけるフレームと光学シートの一部分の断面図。Sectional drawing of a part of flame | frame and optical sheet in the surface light source of 6th Example of this invention. 比較例の面光源におけるフレームと光学シートの一部分の平面図。The top view of a part of frame and optical sheet in the surface light source of the comparative example. 比較例の面光源の図9のX−X矢視線に沿った部分の断面図。Sectional drawing of the part along the XX arrow line of FIG. 9 of the surface light source of a comparative example.
[第1実施例]
図1〜図3に示した第1実施例の面光源は、外部に開口した空間を有するフレーム1と、前記フレーム1内の空間に配置された導光板10及び複数の発光素子14と、前記導光板10の出射面12側に互いに積層して配置された3枚の光学シート19,20,21と、これらの光学シート19,20,21のうちの最も出射側に配置された光学シート21の周縁部の外面に配置された遮光膜22とを備えている。
[First embodiment]
The surface light source of the first embodiment shown in FIGS. 1 to 3 includes a frame 1 having a space opened to the outside, a light guide plate 10 and a plurality of light emitting elements 14 disposed in the space in the frame 1, Three optical sheets 19, 20, and 21 that are stacked on each other on the exit surface 12 side of the light guide plate 10, and the optical sheet 21 that is disposed on the most exit side of these optical sheets 19, 20, and 21. And a light-shielding film 22 disposed on the outer surface of the peripheral edge.
前記フレーム1は、合成樹脂成形品からなっており、前記導光板10及び発光素子14の配置空間を囲む枠状部2と、前記枠状部2の図2及び図3において上側の端面に形成されたシート載置面3と、前記枠状部2の前記端面上に前記シート載置面3を囲んで突設された側壁部4と、前記側壁部4のうちの少なくとも互いに反対側の2つの側壁部4の内面の前記シート載置面3上の部分を、その全長にわたって前記シート載置面3の延長方向、即ち前記枠状部2に対して前記導光板10が配置された側とは反対側の向きに凹入させて形成されたシート差込み溝6とを有している。   The frame 1 is made of a synthetic resin molded product, and is formed on the frame-shaped portion 2 surrounding the space for arranging the light guide plate 10 and the light-emitting element 14 and on the upper end surface of the frame-shaped portion 2 in FIGS. The sheet placement surface 3, the side wall portion 4 projecting from the end surface of the frame-like portion 2 so as to surround the sheet placement surface 3, and at least two of the side wall portions 4 opposite to each other. The portion of the inner surface of one side wall portion 4 on the sheet placement surface 3 extends along the entire length of the sheet placement surface 3, that is, the side on which the light guide plate 10 is disposed with respect to the frame-like portion 2. Has a sheet insertion groove 6 formed to be recessed in the opposite direction.
なお、この実施例の面光源は、図3に仮想線(二点鎖線)で示した液晶表示パネル23に向けて照明光を照射するものであり、前記液晶表示パネル23は、前記フレーム1の前記枠状部2よりも上側の前記側壁部4によって囲まれたスペースに配置される。   In addition, the surface light source of this Example irradiates illumination light toward the liquid crystal display panel 23 shown by the phantom line (two-dot chain line) in FIG. It is arranged in a space surrounded by the side wall part 4 above the frame-like part 2.
前記液晶表示パネル23は、液晶層(図示せず)を挟んで対向配置された観察側とその反対側の一対の透明基板24,25の内面それぞれに複数の画素を形成するための透明電極(図示せず)が設けられ、これらの基板24,25の外面にそれぞれ偏光板26,27が貼付けられた構成のものであり、前記反対側の基板25の一端部に、観察側基板24の外方に張出すドライバ搭載部25aが形成され、このドライバ搭載部25aに、前記複数の画素の電極間に駆動電圧を印加するためのドライバ素子28が搭載されると共に、前記ドライバ素子28に図示しない外部回路からの制御信号を供給するための配線フィルム29の一端が接続されている。   The liquid crystal display panel 23 includes transparent electrodes (not shown) for forming a plurality of pixels on the inner surfaces of a pair of transparent substrates 24 and 25 on the opposite side of the observation side, which are arranged opposite to each other with a liquid crystal layer (not shown) interposed therebetween. (Not shown), and polarizing plates 26 and 27 are attached to the outer surfaces of the substrates 24 and 25, respectively. One end of the substrate 25 on the opposite side is attached to the outside of the observation-side substrate 24. A driver mounting portion 25a extending in the direction is formed, and a driver element 28 for applying a driving voltage between the electrodes of the plurality of pixels is mounted on the driver mounting portion 25a, and the driver element 28 is not illustrated. One end of a wiring film 29 for supplying a control signal from an external circuit is connected.
前記液晶表示パネル23は、矩形形状の平面形状を有しており、前記フレーム1の枠状部2は、前記液晶表示パネル23の外形に対応した矩形枠形状に形成され、前記シート載置面3は前記枠状部2の端面の全周にわたって形成されている。   The liquid crystal display panel 23 has a rectangular planar shape, and the frame portion 2 of the frame 1 is formed in a rectangular frame shape corresponding to the outer shape of the liquid crystal display panel 23, and the sheet placement surface 3 is formed over the entire circumference of the end surface of the frame-like portion 2.
また、前記枠状部2の上側の端面上に前記シート載置面3を囲んで突設された側壁部4のうちの前記液晶表示パネル23のドライバ搭載部25aに対応する部分には、前記配線フィルム29をフレーム1外に引出すための切欠部5が形成されている。   Further, the portion corresponding to the driver mounting portion 25a of the liquid crystal display panel 23 in the side wall portion 4 protruding from the upper end surface of the frame-like portion 2 so as to surround the sheet placement surface 3 includes A cutout portion 5 for drawing the wiring film 29 out of the frame 1 is formed.
一方、前記導光板10は、光を入射させる入射端面11と前記入射端面11から入射した光を出射させる出射面12とを有している。なお、この導光板10は、板状の透明部材からなっており、その1つの端面に前記入射端面11が形成され、2つの板面の一方に前記出射面12が形成され、他方の板面に、前記入射端面11から入射した光を前記出射面12に向けて内面反射する反射面13が形成されている。   On the other hand, the light guide plate 10 has an incident end face 11 on which light is incident and an exit face 12 on which light incident from the incident end face 11 is emitted. The light guide plate 10 is made of a plate-shaped transparent member, the incident end surface 11 is formed on one end surface thereof, the output surface 12 is formed on one of the two plate surfaces, and the other plate surface is formed. In addition, a reflection surface 13 is formed which internally reflects light incident from the incident end surface 11 toward the emission surface 12.
前記導光板10は、前記フレーム1の枠状部2により囲まれた空間に収容される矩形形状に形成されており、前記フレーム1内の前記枠状部2により囲まれた空間に、前記出射面12を前記空間の上側の開口面に対向させて配置されている。   The light guide plate 10 is formed in a rectangular shape that is accommodated in a space surrounded by the frame-like portion 2 of the frame 1, and the light emission plate 10 is formed in the space surrounded by the frame-like portion 2 in the frame 1. The surface 12 is disposed so as to face the upper opening surface of the space.
なお、前記導光板10は、前記フレーム1の枠状部2により囲まれた空間の幅(矩形枠の短辺方向の寸法)よりも僅かに小さい幅と、前記空間の長さ(矩形枠の長辺方向の寸法)よりもある程度小さい長さを有しており、その入射端面11とは反対側の端面と両側面とをそれぞれ前記枠状部2の内周面に近接対向させて前記空間に配置されている。   The light guide plate 10 has a width slightly smaller than the width of the space surrounded by the frame-like portion 2 of the frame 1 (dimension in the short side direction of the rectangular frame) and the length of the space (the rectangular frame). (The dimension in the long side direction) has a length that is somewhat smaller than that, and the end surface opposite to the incident end surface 11 and both side surfaces thereof are close to and opposed to the inner peripheral surface of the frame-shaped portion 2, respectively. Is arranged.
また、前記フレーム1の枠状部2により囲まれた空間のうちの前記導光板10の入射端面11と前記枠状部2の内周面との間の部分には、LED(発光ダイオード)等の複数の発光素子14が、その出射面を前記導光板10の入射端面11に対向させて、前記入射端面11の長さ方向(導光板10の幅方向)に適当間隔で並べて配置されている。   Further, in a space surrounded by the frame-like portion 2 of the frame 1, an LED (light emitting diode) or the like is provided between the incident end surface 11 of the light guide plate 10 and the inner peripheral surface of the frame-like portion 2. The plurality of light emitting elements 14 are arranged at an appropriate interval in the length direction of the incident end surface 11 (width direction of the light guide plate 10) with the emission surface facing the incident end surface 11 of the light guide plate 10. .
前記複数の発光素子14は、これらの発光素子14の接続配線が形成された配線基板15上に設けられており、この配線基板15の一方の側縁部を、前記導光板10の出射面12の入射端面11側の端部に、両面粘着テープ16により貼付けることにより、前記導光板10の入射端面11に対向させて配置されている。   The plurality of light emitting elements 14 are provided on a wiring board 15 on which connection wirings of these light emitting elements 14 are formed, and one side edge portion of the wiring board 15 is disposed on the emission surface 12 of the light guide plate 10. Is attached to the end portion on the incident end surface 11 side with a double-sided adhesive tape 16 so as to face the incident end surface 11 of the light guide plate 10.
なお、前記配線基板15は、前記導光板10の幅と略同じ幅を有しており、その両端縁と前記導光板10への貼付け側とは反対側の側縁とを前記枠状部2の内周面に近接対向させて前記空間に収容されている。   The wiring board 15 has substantially the same width as that of the light guide plate 10, and both frame edges and side edges opposite to the side to be attached to the light guide plate 10 are connected to the frame-like portion 2. And is accommodated in the space so as to face and oppose the inner peripheral surface.
また、前記配線基板15には、前記複数の発光素子14を図示しない発光素子点灯回路に接続するためのリード配線フィルム15aが接続されており、このリード配線フィルム15aは、前記フレーム1の側壁部4に形成された前記切欠部5からフレーム1外に引出されている。   The wiring board 15 is connected to a lead wiring film 15a for connecting the plurality of light emitting elements 14 to a light emitting element lighting circuit (not shown). The lead wiring film 15a is connected to the side wall portion of the frame 1. 4 is pulled out of the frame 1 from the notch 5 formed in the frame 4.
また、前記導光板10の反射面13側には、前記導光板10にその入射端面11から入射した光のうちの前記反射面13からの漏れ光を反射して前記導光板10内に戻すための反射板17が配置されている。   Further, on the reflective surface 13 side of the light guide plate 10, the light leaked from the reflective surface 13 out of the light incident on the light guide plate 10 from the incident end surface 11 is reflected back into the light guide plate 10. The reflector 17 is arranged.
この反射板17は、前記導光板10の外形よりも大きく、且つ周縁部が前記フレーム1の枠状部2の下側の端面の内周側の部分に対向する矩形形状に形成されたアルミニウム板等の金属板からなっており、前記導光板10の反射面13の周縁部に、両面粘着テープ18によって貼付けられている。   The reflecting plate 17 is an aluminum plate formed in a rectangular shape that is larger than the outer shape of the light guide plate 10 and that has a peripheral portion facing the inner peripheral side portion of the lower end surface of the frame-like portion 2 of the frame 1. The light guide plate 10 is affixed to the periphery of the reflective surface 13 with a double-sided adhesive tape 18.
さらに、前記両面粘着テープ18は、前記導光板10の縁部から前記反射板17の外側縁にわたる幅を有しており、前記導光板10と反射板17は、前記両面粘着テープ18の外側の縁部を前記枠状部2の下側端面に貼付けることにより、前記枠状部2に支持されている。   Further, the double-sided pressure-sensitive adhesive tape 18 has a width extending from the edge of the light guide plate 10 to the outer edge of the reflection plate 17, and the light guide plate 10 and the reflection plate 17 are arranged outside the double-sided pressure-sensitive adhesive tape 18. The frame portion 2 is supported by sticking the edge portion to the lower end surface of the frame portion 2.
なお、前記枠状部2の下側端面は、その内周側の部分をその全周にわたって凹入させた形状に形成されており、前記反射板17は、前記枠状部2の下側端面の凹入面に前記両面粘着テープ18によって貼付けられている。   The lower end surface of the frame-shaped portion 2 is formed in a shape in which a portion on the inner peripheral side is recessed over the entire circumference, and the reflecting plate 17 is a lower end surface of the frame-shaped portion 2. The double-sided pressure-sensitive adhesive tape 18 is attached to the recessed surface.
一方、前記導光板10の出射面12側に互いに積層して配置された3枚の光学シート19,20,21のうちの前記導光板10の出射面12上に配置された光学シート19は、前記導光板10の出射面12からの出射光を拡散させる拡散シートであり、この拡散シート19は、光散乱粒子が分散された透明な粘着剤層または光散乱粒子が分散された透明な樹脂フィルムからなっている。   On the other hand, of the three optical sheets 19, 20, and 21 disposed on the light exit surface 12 side of the light guide plate 10, the optical sheet 19 disposed on the light exit surface 12 of the light guide plate 10 is: The diffusion sheet 19 is a diffusion sheet for diffusing light emitted from the emission surface 12 of the light guide plate 10. The diffusion sheet 19 is a transparent adhesive layer in which light scattering particles are dispersed or a transparent resin film in which light scattering particles are dispersed. It is made up of.
また、拡散シート19の上に配置された2枚の光学シート20,21は、一方の面が平坦面に形成され、他方の面に複数の微細なプリズム部20a,21aが密なピッチで形成された第1プリズムシート及び第2プリズムシートであり、それぞれの平坦面を前記導光板10側に向けて配置されている。   The two optical sheets 20 and 21 disposed on the diffusion sheet 19 have one surface formed as a flat surface and a plurality of fine prism portions 20a and 21a formed at a dense pitch on the other surface. The first prism sheet and the second prism sheet are arranged with their flat surfaces facing the light guide plate 10 side.
この第1プリズムシート20と第2プリズムシート21は、前記導光板10の出射面12から出射し前記拡散シート19により拡散された光を前記導光板10の出射面12の法線方向に対する角度が小さくなる方向に屈折させ、前記法線方向、つまり正面方向の出射光強度が高い強度分布の照明光を出射するために設けられている。   The first prism sheet 20 and the second prism sheet 21 have an angle with respect to the normal direction of the exit surface 12 of the light guide plate 10 that is emitted from the exit surface 12 of the light guide plate 10 and diffused by the diffusion sheet 19. The light beam is refracted in a decreasing direction, and is provided to emit illumination light having an intensity distribution in which the emitted light intensity in the normal direction, that is, the front direction is high.
なお、前記第1プリズムシート20複数のプリズム部20aと、前記第2プリズムシート21の複数のプリズム部21aは、互いに異なる方向に沿った線状プリズム部であり、例えば、前記第1プリズムシート20の複数のプリズム部20aは、前記導光板10の幅方向と平行な方向に沿わせて互いに平行に形成され、前記第2プリズムシート21の複数のプリズム部21aは、前記導光板10の幅方向に対して直交する方向に沿わせて互いに平行に形成されている。   The plurality of prism portions 20a of the first prism sheet 20 and the plurality of prism portions 21a of the second prism sheet 21 are linear prism portions along different directions, for example, the first prism sheet 20 The plurality of prism portions 20 a are formed in parallel with each other along a direction parallel to the width direction of the light guide plate 10, and the plurality of prism portions 21 a of the second prism sheet 21 are formed in the width direction of the light guide plate 10. Are formed parallel to each other along a direction orthogonal to the direction.
そして、前記第1プリズムシート20及び第2プリズムシート21のうち、前記拡散シート19の上に配置された第1プリズムシート20は、前記導光板10の外形と略同じ矩形形状に形成され、また、前記導光板10の出射面12と前記第1プリズムシート20との間に配置された前記拡散シート19は、前記第1プリズムシート20と略同じ矩形形状に形成されており、前記第1プリズムシート20は、その平坦面を前記導光板10側に向けて前記拡散シート19の上に重ねて配置され、前記拡散シート19を介して前記導光板10の出射面12上に貼付けられている。   Of the first prism sheet 20 and the second prism sheet 21, the first prism sheet 20 disposed on the diffusion sheet 19 is formed in a rectangular shape substantially the same as the outer shape of the light guide plate 10, and The diffusion sheet 19 disposed between the light exit surface 12 of the light guide plate 10 and the first prism sheet 20 is formed in a substantially same rectangular shape as the first prism sheet 20, and the first prism. The sheet 20 is disposed so as to overlap the diffusion sheet 19 with its flat surface facing the light guide plate 10, and is stuck on the emission surface 12 of the light guide plate 10 via the diffusion sheet 19.
一方、前記第1プリズムシート20の上に配置された第2プリズムシート21は、その周縁部が全周にわたって前記導光板10の周囲に張出し、且つ各辺の全てが、これらの辺の全長にわたって直線辺に形成された矩形形状に形成されている。   On the other hand, the second prism sheet 21 disposed on the first prism sheet 20 has a peripheral portion that protrudes around the light guide plate 10 over the entire circumference, and all the sides extend over the entire length of these sides. It is formed in a rectangular shape formed on a straight side.
そして、この第2プリズムシート21は、その平坦面を前記導光板10側に向けて、周縁部を前記フレーム1の前記シート載置面3上に載置すると共に、少なくとも互いに反対側の2つの辺の縁部の先端を、前記フレーム1に設けられた前記シート差込み溝6に差込んで配置されている。   The second prism sheet 21 has a flat surface directed toward the light guide plate 10 and a peripheral portion placed on the sheet placement surface 3 of the frame 1 and at least two opposite sides. The front edge of the side edge is inserted into the sheet insertion groove 6 provided in the frame 1.
この実施例では、前記フレーム1の枠状部2の上側端面上に突設された側壁部4のうちの前記枠状部2の長さ方向(導光板10の幅方向に直交する方向)の両端側の側壁部4に前記シート差込み溝6を設け、前記第2プリズムシート21の長さ方向(導光板10の幅方向に直交する方向)の両端側の2つの辺の縁部の先端を前記シート差込み溝6に差込んでいる。   In this embodiment, the length direction of the frame-like portion 2 of the side wall portion 4 projecting on the upper end surface of the frame-like portion 2 of the frame 1 (direction orthogonal to the width direction of the light guide plate 10). The sheet insertion grooves 6 are provided in the side wall portions 4 on both ends, and the ends of the edges of the two sides on both ends in the length direction of the second prism sheet 21 (direction perpendicular to the width direction of the light guide plate 10) are provided. The sheet is inserted into the sheet insertion groove 6.
なお、前記第2プリズムシート21は、無理なく湾曲させることができる可撓性を有しており、従って、この第2プリズムシート21の一端側の縁部の先端を前記枠状部2の長さ方向の一端側の側壁部4に設けられたシート差込み溝6に差込み、次いで前記第2プリズムシート21を湾曲させて、この第2プリズムシート21の他端側の縁部の先端を前記枠状部2の長さ方向の他端側の側壁部4に設けられたシート差込み溝6に差込んだ後に、前記第2プリズムシート21をその弾性によりフラットな状態に復帰させることにより、容易に前記シート載置面3上に載置することができる。   The second prism sheet 21 is flexible enough to bend without difficulty. Therefore, the tip of the edge on the one end side of the second prism sheet 21 is the length of the frame-like portion 2. The second prism sheet 21 is inserted into a sheet insertion groove 6 provided in the side wall 4 on one end side in the vertical direction, and then the second prism sheet 21 is bent, and the tip of the edge on the other end side of the second prism sheet 21 is attached to the frame. After the second prism sheet 21 is returned to a flat state due to its elasticity after being inserted into the sheet insertion groove 6 provided in the side wall portion 4 on the other end side in the length direction of the shape portion 2, It can be placed on the sheet placement surface 3.
また、前記3枚の光学シート19,20,21のうちの最も出射側に配置された第2プリズムシート21の周縁部の外面に配置された遮光膜22は、前記フレーム1の枠状部2の内周面と前記導光板10の外周縁との間の領域を覆う枠形状に形成されており、前記第2プリズムシート21の外面(図3の上側)にその周縁部の全周にわって配置され、前記第2プリズムシート21の上に図示しない両面粘着テープにより貼付けられている。   Further, the light shielding film 22 disposed on the outer surface of the peripheral portion of the second prism sheet 21 disposed on the most emission side of the three optical sheets 19, 20, 21 is the frame-shaped portion 2 of the frame 1. Is formed in a frame shape that covers a region between the inner peripheral surface of the light guide plate 10 and the outer peripheral edge of the light guide plate 10, and is arranged on the outer surface (upper side in FIG. 3) of the second prism sheet 21 over the entire periphery. Disposed on the second prism sheet 21 with a double-sided adhesive tape (not shown).
前記遮光膜22は、前記導光板10の入射端面11と前記フレーム1の枠状部2と間の領域、つまり複数の発光素子14が設けられた配線基板15の配置部に対応する部分の幅が、前記導光板10の他の外周縁と前記枠状部2と間の領域に対応する部分の幅よりも広い枠形状に形成されている。   The light shielding film 22 has a width corresponding to a region between the incident end face 11 of the light guide plate 10 and the frame-like portion 2 of the frame 1, that is, a placement portion of the wiring substrate 15 provided with a plurality of light emitting elements 14. However, it is formed in a frame shape wider than the width of the portion corresponding to the region between the other outer peripheral edge of the light guide plate 10 and the frame-shaped part 2.
この面光源は、前記導光板10の出射面12から出射した光を前記拡散シート19により拡散し、その光を、前記第1プリズムシート20及び前記第2プリズムシート21により、前記導光板10の出射面12の法線方向に対する角度が小さくなる方向に屈折させて出射する。   The surface light source diffuses the light emitted from the light exit surface 12 of the light guide plate 10 by the diffusion sheet 19, and the light is emitted from the light guide plate 10 by the first prism sheet 20 and the second prism sheet 21. The light is refracted in a direction in which the angle with respect to the normal direction of the emission surface 12 becomes smaller and emitted.
そして、この面光源は、前記フレーム1の前記導光板10及び前記複数の発光素子14の配置空間を囲む枠状部2の端面にシート載置面3を形成し、前記3枚の光学シート19,20,21のうちの最も出射側に配置された第2プリズムシート21を、周縁部が全周にわたって前記導光板10の周囲に張出し、且つ各辺の全てが、これらの辺の全長にわたって直線辺に形成された形状に形成し、この第2プリズムシート21を、その周縁部を前記フレーム1の前記シート載置面3上に載置して配置しているため、輝度むらの無い均一な輝度分布の光を照射することができる。   The surface light source forms a sheet placement surface 3 on an end surface of the frame-like portion 2 surrounding the arrangement space of the light guide plate 10 and the plurality of light emitting elements 14 of the frame 1, and the three optical sheets 19. , 20 and 21, the second prism sheet 21 arranged on the most exit side is projected around the light guide plate 10 over the entire circumference, and all of the sides are straight over the entire length of these sides. The second prism sheet 21 is formed in a shape formed on the side, and the peripheral edge portion thereof is placed on the sheet placement surface 3 of the frame 1, so that there is no uneven brightness. Light with a luminance distribution can be irradiated.
すなわち、図9及び図10に示した比較例の面光源は、最も出射側に配置された光学シート(例えばプリズムシート)33を、その周縁部の複数箇所に耳状の凸部34を形成した形状に形成し、この光学シート33をフレーム30内の空間に、前記耳状の凸部34を前記フレーム30の枠状部31の端面に形成された凹入面32に支持させて配置したものであり、この比較例の面光源は、前記光学シート33の耳状の凸部34の付近の領域Aから、他の領域からの出射光とは異なる輝度の光が出射し、照射光に輝度むらを生じる。   That is, in the surface light source of the comparative example shown in FIGS. 9 and 10, the optical sheet (for example, prism sheet) 33 arranged on the most emission side is formed, and the ear-shaped convex portions 34 are formed at a plurality of positions on the peripheral edge thereof. The optical sheet 33 is formed in a shape, and the optical sheet 33 is disposed in a space in the frame 30 and the ear-shaped convex portion 34 is supported by a concave insertion surface 32 formed on the end surface of the frame-shaped portion 31 of the frame 30. The surface light source of this comparative example emits light having a brightness different from that of the light emitted from the other area from the area A in the vicinity of the ear-shaped convex portion 34 of the optical sheet 33, and the brightness of the irradiated light Causes unevenness.
この比較例の面光源における照射光の輝度むらは、前記光学シート33の周縁部の上に遮光膜35を配置することによってある程度目立たなくすることができるが、その場合でも、前記光学シート33の法線方向に対して斜めに傾いた方向から観察すると、前記輝度むらが見える。   The brightness unevenness of the irradiated light in the surface light source of this comparative example can be made inconspicuous to some extent by arranging the light shielding film 35 on the peripheral edge of the optical sheet 33. When observed from a direction inclined obliquely with respect to the normal direction, the luminance unevenness can be seen.
なお、この比較例の面光源において、前記遮光膜35を、前記異なる輝度の光が出射する領域Aを完全に覆い隠すように幅広に形成すれば、斜めに傾いた方向から観察したときも輝度むらが見えないようにすることができるが、前記遮光膜35を幅広に形成したのでは、照明光の照射領域の面積が小さくなってしまう。   In addition, in the surface light source of this comparative example, if the light shielding film 35 is formed wide so as to completely cover the region A from which the light having different luminance is emitted, the luminance can be obtained even when observed obliquely. Although unevenness can be made invisible, if the light shielding film 35 is formed wide, the area of the illumination light irradiation region is reduced.
このような比較例に対して、上記実施例の面光源は、最も出射側に配置された前記第2プリズムシート21を、その周縁部が全周にわたって前記導光板10の周囲に張出し、且つ各辺の全てが、これらの辺の全長にわたって直線辺に形成された形状に形成し、この第2プリズムシート21を、その周縁部を前記フレーム1の前記シート載置面3上に載置して配置しているため、前記第2プリズムシート21の全域から略同じ輝度の光を出射させ、前記第2プリズムシート21の法線方向から観察したときはもちろん、前記法線方向に対して斜めに傾いた方向から観察したときも輝度むらが見えない、均一な輝度分布の光を照射することができる。   In contrast to such a comparative example, the surface light source of the above-described embodiment has the second prism sheet 21 arranged on the most emission side, the peripheral edge of which extends around the light guide plate 10 over the entire circumference, and each All of the sides are formed in a shape formed into a straight side over the entire length of these sides, and the second prism sheet 21 is placed on the sheet placement surface 3 of the frame 1 with the peripheral edge thereof. Therefore, when the light is emitted from the entire area of the second prism sheet 21 and observed from the normal direction of the second prism sheet 21, of course, the light is oblique to the normal direction. Even when observed from an inclined direction, it is possible to irradiate light having a uniform luminance distribution in which luminance unevenness is not visible.
また、上記実施例の面光源は、前記フレーム1の枠状部2を矩形枠形状に形成し、前記シート載置面3を前記枠状部2の上側端面の全周にわたって形成すると共に、前記導光板10を、前記フレーム1の前記枠状部2により囲まれた空間に収容される矩形形状に形成し、前記第2プリズムシート21を、その周縁部が前記シート載置面3上に重なる矩形形状に形成しているため、矩形形状の出射領域の全域から、輝度むらの無い均一な輝度分布の光を照射することができる。   In the surface light source of the above embodiment, the frame-like portion 2 of the frame 1 is formed in a rectangular frame shape, the sheet placement surface 3 is formed over the entire circumference of the upper end surface of the frame-like portion 2, and The light guide plate 10 is formed in a rectangular shape that is accommodated in the space surrounded by the frame-shaped portion 2 of the frame 1, and the peripheral edge of the second prism sheet 21 overlaps the sheet placement surface 3. Since it is formed in a rectangular shape, light having a uniform luminance distribution with no luminance unevenness can be irradiated from the entire rectangular emission region.
さらに、上記実施例の面光源は、前記フレーム1を、前記導光板10及び前記複数の発光素子14の配置空間を囲む枠状部2と、前記枠状部2の端面上に前記シート載置面3を囲んで突設された側壁部4と、前記側壁部4のうちの互いに反対側の2つの側壁部4の内面の前記シート載置面3上の部分を、その全長にわたって前記シート載置面3の延長方向に凹入させて形成されたシート差込み溝6とを有する形状に形成し、前記第2プリズムシート21を、その互いに反対側の2つの辺の縁部の先端を前記シート差込み溝6に差込んで前記シート載置面3上に配置しているため、前記第2プリズムシート21を、前記シート差込み溝6により位置決めすると共に、みだりに脱落しないように配置することができる。   Further, in the surface light source of the above embodiment, the frame 1 is mounted on the sheet on the frame-like part 2 surrounding the arrangement space of the light guide plate 10 and the plurality of light-emitting elements 14 and the end face of the frame-like part 2. A portion on the sheet placement surface 3 of an inner surface of the side wall portion 4 projecting around the surface 3 and the two side wall portions 4 on the opposite sides of the side wall portion 4 is placed over the entire length of the sheet. The second prism sheet 21 is formed in a shape having a sheet insertion groove 6 formed by being recessed in the extending direction of the mounting surface 3, and the tips of the edges of two sides opposite to each other are formed on the sheet. Since it is inserted into the insertion groove 6 and disposed on the sheet placement surface 3, the second prism sheet 21 can be positioned by the sheet insertion groove 6 and can be disposed so as not to fall off unnecessarily.
また、上記実施例の面光源は、前記第2プリズムシート21の周縁部の外面に、前記フレーム1の枠状部2の内周面と前記導光板10の外周縁との間の領域を覆う形状に形成された遮光膜22を配置しているため、輪郭がシャープな矩形形状の光を照射することができる。   Further, the surface light source of the above embodiment covers a region between the inner peripheral surface of the frame-like portion 2 of the frame 1 and the outer peripheral edge of the light guide plate 10 on the outer surface of the peripheral portion of the second prism sheet 21. Since the light shielding film 22 formed in a shape is arranged, light having a rectangular shape with a sharp outline can be irradiated.
さらに、上記実施例の面光源は、前記導光板10の出射面12上に配置された拡散シート19と、この拡散シート19上に配置された第1プリズムシート20とを、前記導光板10の外形と略同じ形状に形成し、最も出射側に配置された前記第2プリズムシート21を、その周縁部が全周にわたって前記導光板10の周囲に張出す形状に形成しているため、前記導光板10の出射面12から出射した光のほとんどを前記拡散シート19により拡散すると共に前記第1プリズムシート20により屈折させ、その光の全てを前記第2プリズムシート21により屈折させて出射することができ、従って前記複数の発光素子14が発する光を効率良く前記第2プリズムシート21の全域から出射することができる。   Further, the surface light source of the above embodiment includes a diffusion sheet 19 disposed on the emission surface 12 of the light guide plate 10 and a first prism sheet 20 disposed on the diffusion sheet 19 of the light guide plate 10. The second prism sheet 21 that is formed in substantially the same shape as the outer shape and is arranged on the most exit side is formed in a shape in which the peripheral edge extends around the light guide plate 10 over the entire circumference. Most of the light emitted from the emission surface 12 of the optical plate 10 is diffused by the diffusion sheet 19 and refracted by the first prism sheet 20, and all the light is refracted by the second prism sheet 21 and emitted. Therefore, the light emitted from the plurality of light emitting elements 14 can be efficiently emitted from the entire area of the second prism sheet 21.
なお、上記実施例では、前記フレーム1の枠状部2の上側端面上に突設された側壁部4のうちの前記枠状部2の長さ方向の両端側の側壁部4に前記シート差込み溝6を設け、前記第2プリズムシート21の長さ方向の両端側の2つの辺の縁部の先端を前記シート差込み溝6に差込んでいるが、前記フレーム1の側壁部4のうちの前記枠状部2の幅方向の両端側の側壁部4に前記シート差込み溝6を設け、前記第2プリズムシート21の幅方向の両端側の2つの辺の縁部の先端を前記シート差込み溝6に差込んでもよい。   In the above-described embodiment, the sheet is inserted into the side wall portions 4 on both end sides in the length direction of the frame-like portion 2 out of the side wall portions 4 protruding on the upper end surface of the frame-like portion 2 of the frame 1. A groove 6 is provided, and the leading ends of two side edges of the second prism sheet 21 in the length direction are inserted into the sheet insertion groove 6. Of the side walls 4 of the frame 1, The sheet insertion grooves 6 are provided in the side wall portions 4 on both ends in the width direction of the frame-shaped portion 2, and the ends of the edges of the two sides on both ends in the width direction of the second prism sheet 21 are formed on the sheet insertion grooves. 6 may be inserted.
また、上記実施例では、前記第2プリズムシート21を、その各辺の全てが直線辺に形成された形状に形成しているが、前記第2プリズムシート21は、前記発光素子14の配置側に対向する一辺とこれに隣接する二辺を、これらの辺の全長にわたって直線辺に形成した形状に形成してもよい。   Moreover, in the said Example, although the said 2nd prism sheet 21 is formed in the shape by which all the each sides were formed in the linear side, the said 2nd prism sheet 21 is the arrangement | positioning side of the said light emitting element 14. You may form in the shape which formed the one side which opposes to this, and two sides adjacent to this in the linear side over the full length of these sides.
[第2実施例]
さらに、上記第1実施例では、前記遮光膜22を前記第2プリズムシート21の周縁部の全周にわって配置しているが、この遮光膜22は、図4に示した第2実施例のように、前記第2プリズムシート21の周縁部のうちの前記発光素子14の配置側に対応する縁部だけに配置してもよい。
[Second Embodiment]
Further, in the first embodiment, the light shielding film 22 is arranged along the entire periphery of the peripheral portion of the second prism sheet 21, and the light shielding film 22 is formed in the second embodiment shown in FIG. As described above, the second prism sheet 21 may be disposed only at the edge corresponding to the arrangement side of the light emitting element 14 in the peripheral portion of the second prism sheet 21.
[第3実施例]
図5に示した第3実施例の面光源は、前記フレーム1の側壁部4の内周面に、その全周にわたって前記シート差込み溝6を設け、前記第2プリズムシート21の全ての辺の縁部の先端を前記シート差込み溝6に差込んだものであり、他の構成は上記第1実施例と同じである。
[Third embodiment]
In the surface light source of the third embodiment shown in FIG. 5, the sheet insertion groove 6 is provided on the inner peripheral surface of the side wall portion 4 of the frame 1 over the entire periphery, and all the sides of the second prism sheet 21 are provided. The front end of the edge is inserted into the sheet insertion groove 6, and the other configuration is the same as in the first embodiment.
[第4実施例]
また、図6に示した第4実施例の面光源は、遮光膜22を、その外周縁が前記第2プリズムシート21の外周縁と略一致する形状に形成し、前記第2プリズムシート21の縁部の先端と前記遮光膜22の縁部の先端とを重ね合わせて前記シート差込み溝6に差込んだものであり、他の構成は第1実施例の面光源と同じである。
[Fourth embodiment]
In the surface light source of the fourth embodiment shown in FIG. 6, the light shielding film 22 is formed in a shape in which the outer peripheral edge substantially coincides with the outer peripheral edge of the second prism sheet 21. The leading edge of the edge and the leading edge of the edge of the light shielding film 22 are overlapped and inserted into the sheet insertion groove 6, and other configurations are the same as those of the surface light source of the first embodiment.
[第5実施例]
図7に示した第5実施例の面光源は、前記フレーム1を、前記シート差込み溝6を有しない形状、つまり、前記導光板10及び前記発光素子14の配置空間を囲む枠状部2と、前記枠状部2の端面上に前記シート載置面3を囲んで突設された側壁部4とを有する形状に形成し、前記第2プリズムシート21を、その少なくとも互いに反対側の2つの辺の縁部の先端位置を前記側壁部4の内面により位置決めして前記シート載置面3上に配置したものであり、他の構成は第1実施例の面光源と同じである。
[Fifth embodiment]
In the surface light source of the fifth embodiment shown in FIG. 7, the frame 1 is shaped so as not to have the sheet insertion groove 6, that is, the frame-like portion 2 surrounding the arrangement space of the light guide plate 10 and the light emitting element 14. And a side wall portion 4 protruding from the end surface of the frame-like portion 2 so as to surround the sheet mounting surface 3, and the second prism sheet 21 is at least two opposite to each other. The front end position of the edge of the side is positioned by the inner surface of the side wall portion 4 and arranged on the sheet placing surface 3, and the other configurations are the same as those of the surface light source of the first embodiment.
[第6実施例]
図8に示した第8実施例の面光源は、前記フレーム1を、前記シート差込み溝6を有さず、且つ、前記シート載置面3を、前記枠状部2の端面の内周側の部分をその全周にわたって前記シート載置面3に対して前記側壁部4が突設された側とは反対側の向きに凹入させて形成した形状に形成し、前記第2プリズムシート21を、その少なくとも互いに反対側の2つの辺の縁部の先端位置を前記凹入したシート載置面3の外側の立上がり面により位置決めして前記シート載置面3上に配置したものであり、他の構成は第1実施例の面光源と同じである。
[Sixth embodiment]
In the surface light source of the eighth embodiment shown in FIG. 8, the frame 1 does not have the sheet insertion groove 6, and the sheet placement surface 3 serves as the inner peripheral side of the end surface of the frame-like portion 2. The second prism sheet 21 is formed in a shape that is recessed in the direction opposite to the side on which the side wall 4 protrudes with respect to the sheet placement surface 3 over the entire circumference. Is positioned on the sheet placement surface 3 by positioning the tip positions of at least the edges of the two sides opposite to each other with the rising surface on the outside of the recessed sheet placement surface 3; Other configurations are the same as those of the surface light source of the first embodiment.
[他の実施例]
なお、上記各実施例の面光源は、前記導光板10の出射面12側に、拡散シート19と第1プリズムシート20と第2プリズムシート21との3枚の光学シートを配置したものであるが、前記導光板10の出射面12側に配置する光学シートは、前記拡散シート19と第2プリズムシート20との2枚の光学シートでも、前記第1プリズムシート20と第2プリズムシート21との2枚の光学シートでも、或いは前記第2プリズムシート21だけの1枚の光学シートでもよい。
[Other embodiments]
In the surface light source of each of the above embodiments, three optical sheets of the diffusion sheet 19, the first prism sheet 20, and the second prism sheet 21 are arranged on the light exit surface 12 side of the light guide plate 10. However, the optical sheet disposed on the light exit surface 12 side of the light guide plate 10 may be the two optical sheets of the diffusion sheet 19 and the second prism sheet 20, or the first prism sheet 20 and the second prism sheet 21. Or two optical sheets, or only one optical sheet of the second prism sheet 21.
また、最も出射側に配置する光学シートは、前記第2プリズムシート21に限らず、例えば偏光板等の他の光学シートでもよく、その場合も、この最も出射側の光学シートを、周縁部が全周にわたって前記導光板10の周囲に張出し、且つ各辺の全てまたは前記発光素子14の配置側に対向する一辺とこれに隣接する二辺が、これらの辺の全長にわたって直線辺に形成された形状に形成し、この光学シートの周縁部を前記フレーム1のシート載置面3上に載置して配置することにより、輝度むらの無い均一な輝度分布の光を照射することができる。   Further, the optical sheet disposed on the most exit side is not limited to the second prism sheet 21, and may be another optical sheet such as a polarizing plate. The entire surface of the light guide plate 10 is projected over the entire periphery, and all sides or one side facing the light emitting element 14 is disposed on the straight side over the entire length of these sides. By forming the optical sheet in a shape and placing the periphery of the optical sheet on the sheet placement surface 3 of the frame 1, light having a uniform luminance distribution without uneven luminance can be irradiated.
1…フレーム、2…枠状部、3…シート載置面、4…側壁部、6…シート差込み溝、10…導光板、11…入射端面、12…出射面、13…反射面、14…発光素子、15…配線基板、16…両面粘着テープ、17…反射板、18…両面粘着テープ、19…拡散シート(光学シート)、20…第1プリズムシート(光学シート)、21…第2プリズムシート(光学シート)、20a,21a…プリズム部、22…遮光膜、23…液晶表示パネル   DESCRIPTION OF SYMBOLS 1 ... Frame, 2 ... Frame-shaped part, 3 ... Sheet mounting surface, 4 ... Side wall part, 6 ... Sheet insertion groove, 10 ... Light guide plate, 11 ... Incident end surface, 12 ... Output surface, 13 ... Reflecting surface, 14 ... Light emitting element, 15 ... Wiring substrate, 16 ... Double-sided adhesive tape, 17 ... Reflector, 18 ... Double-sided adhesive tape, 19 ... Diffusion sheet (optical sheet), 20 ... First prism sheet (optical sheet), 21 ... Second prism Sheet (optical sheet), 20a, 21a ... prism portion, 22 ... light shielding film, 23 ... liquid crystal display panel

Claims (12)

  1. 外部に開口した空間を有するフレームと、
    光を入射させる入射端面と前記入射端面から入射した光を出射させる出射面とを有し、前記フレーム内の空間に、前記出射面を前記空間の開口面に対向させて配置された導光板と、
    前記フレーム内の空間に、前記導光板の入射端面に対向させて配置された発光素子と、
    前記導光板の出射面側に配置された光学シートと、を備えた面光源において、
    前記フレームは、前記導光板及び前記発光素子の配置空間を囲む枠状部の端面に形成されたシート載置面を有し、
    前記光学シートは、周縁部が全周にわたって前記導光板の周囲に張出し、且つ各辺の全てまたは前記発光素子の配置側の辺に対向する一辺とこれに隣接する二辺が、これらの辺の全長にわたって直線辺に形成された形状を有し、前記周縁部を前記フレームの前記シート載置面上に載置して配置されていることを特徴とする面光源。
    A frame having a space opened to the outside;
    A light guide plate having an incident end surface for entering light and an exit surface for emitting light incident from the incident end surface, and disposed in a space in the frame with the exit surface facing an opening surface of the space; ,
    A light emitting element disposed in the space in the frame so as to face the incident end face of the light guide plate;
    In a surface light source comprising an optical sheet disposed on the light exit surface side of the light guide plate,
    The frame has a sheet placement surface formed on an end surface of a frame-shaped portion that surrounds an arrangement space of the light guide plate and the light emitting element,
    The optical sheet has a peripheral edge that extends around the entire circumference of the light guide plate, and one side that faces all of the sides or the side on which the light emitting element is disposed and two sides that are adjacent to these sides are A surface light source characterized by having a shape formed on a straight side over its entire length and placing the peripheral edge on the sheet placement surface of the frame.
  2. 前記フレームの枠状部は矩形枠形状に形成され、前記シート載置面は前記枠状部の端面の全周にわたって形成されており、前記導光板は、前記フレームの前記枠状部により囲まれた空間に収容される矩形形状に形成され、前記光学シートは、その周縁部が前記シート載置面上に重なる矩形形状に形成されていることを特徴とする請求項1に記載の面光源。   The frame-shaped portion of the frame is formed in a rectangular frame shape, the sheet placement surface is formed over the entire periphery of the end surface of the frame-shaped portion, and the light guide plate is surrounded by the frame-shaped portion of the frame. 2. The surface light source according to claim 1, wherein the optical sheet is formed in a rectangular shape that is accommodated in a space, and the optical sheet is formed in a rectangular shape with a peripheral edge overlapping the sheet placement surface.
  3. 前記フレームは、前記導光板及び前記発光素子の配置空間を囲む枠状部と、前記枠状部の端面上に前記シート載置面を囲んで突設された側壁部と、前記側壁部のうちの少なくとも互いに反対側の2つの側壁部の内面の前記シート載置面上の部分を、その全長にわたって前記シート載置面の延長方向に凹入させて形成されたシート差込み溝とを有しており、前記光学シートは、その少なくとも互いに反対側の2つの辺の縁部の先端を前記シート差込み溝に差込んで前記シート載置面上に配置されていることを特徴とする請求項1または2に記載の面光源。   The frame includes a frame-shaped portion surrounding an arrangement space for the light guide plate and the light-emitting element, a side wall portion projecting from the end surface of the frame-shaped portion so as to surround the sheet placement surface, and the side wall portion. A sheet insertion groove formed by recessing a portion of the inner surface of the two side wall portions opposite to each other on the sheet placement surface over the entire length thereof in the extending direction of the sheet placement surface. The optical sheet is arranged on the sheet placing surface with at least tips of edges of two sides opposite to each other being inserted into the sheet insertion groove. 2. A surface light source according to 2.
  4. 前記光学シートの周縁部の外面にその周縁部の全周にわたって、前記フレームの枠状部の内周面と前記導光板の外周縁との間の領域を覆う形状に形成された遮光膜が配置され、前記光学シート及び前記遮光膜は、その少なくとも互いに反対側の2つの辺の縁部の先端をそれぞれ前記シート差込み溝に差込んで前記シート載置面上に配置されていることを特徴とする請求項3に記載の面光源。   A light-shielding film formed in a shape covering the area between the inner peripheral surface of the frame-shaped portion of the frame and the outer peripheral edge of the light guide plate is arranged on the outer surface of the peripheral portion of the optical sheet over the entire periphery of the peripheral portion. The optical sheet and the light-shielding film are arranged on the sheet placement surface with at least tips of edges of two sides opposite to each other being inserted into the sheet insertion groove, respectively. The surface light source according to claim 3.
  5. 前記フレームは、前記導光板及び前記発光素子の配置空間を囲む枠状部と、前記枠状部の端面上に前記シート載置面を囲んで突設された側壁部とを有しており、前記光学シートは、その少なくとも互いに反対側の2つの辺の縁部の先端位置を前記側壁部の内面により位置決めして前記シート載置面上に配置されていることを特徴とする請求項1または2に記載の面光源。   The frame includes a frame-shaped portion that surrounds an arrangement space of the light guide plate and the light-emitting element, and a side wall portion that protrudes from the end surface of the frame-shaped portion so as to surround the sheet placement surface. 2. The optical sheet is arranged on the sheet placement surface with at least tip positions of edges of two sides opposite to each other positioned by an inner surface of the side wall portion. 2. A surface light source according to 2.
  6. 前記フレームの前記シート載置面は、前記フレームの枠状部の端面を凹入させて形成されており、前記光学シートは、その少なくとも互いに反対側の2つの辺の縁部の先端位置を前記凹入したシート載置面の外側の立上がり面により位置決めして前記シート載置面上に配置されていることを特徴とする請求項1または2に記載の面光源。   The sheet mounting surface of the frame is formed by recessing the end surface of the frame-shaped portion of the frame, and the optical sheet has the tip positions of the edge portions of at least two sides opposite to each other. The surface light source according to claim 1, wherein the surface light source is positioned on the sheet placement surface while being positioned by a rising surface on the outside of the recessed sheet placement surface.
  7. 前記光学シートの周縁部の外面に、前記フレームの枠状部の内周面と前記導光板の外周縁との間の領域を覆う形状に形成された遮光膜が配置されていることを特徴とする請求項1〜3及び請求項5〜6の何れか一つに記載の面光源。   A light-shielding film formed in a shape covering a region between the inner peripheral surface of the frame-shaped portion of the frame and the outer peripheral edge of the light guide plate is disposed on the outer surface of the peripheral portion of the optical sheet. The surface light source as described in any one of Claims 1-3 and Claims 5-6.
  8. 前記遮光膜は、前記光学シートの周縁部の全周にわって配置されていることを特徴とする請求項7に記載の面光源。   The surface light source according to claim 7, wherein the light shielding film is disposed over the entire circumference of the peripheral edge of the optical sheet.
  9. 前記遮光膜は、前記光学シートの周縁部のうちの前記発光素子の配置側に対応する縁部に配置されていることを特徴とする請求項7に記載の面光源。   The surface light source according to claim 7, wherein the light shielding film is disposed on an edge portion corresponding to the light emitting element arrangement side in a peripheral portion of the optical sheet.
  10. 前記光学シートは、一方の面が平坦面に形成され、他方の面に複数の微細なプリズム部が配列形成されたプリズムシートであることを特徴とする請求項1〜9の何れか一つに記載の面光源。   The optical sheet according to any one of claims 1 to 9, wherein the optical sheet is a prism sheet in which one surface is formed as a flat surface and a plurality of fine prism portions are arranged on the other surface. The surface light source described.
  11. 前記導光板の出射面側に、前記導光板の外形と略同じ形状に形成された第1プリズムシートと、周縁部が全周にわたって前記導光板の周囲に張出し、且つ各辺の全てまたは前記発光素子の配置側に対向する一辺とこれに隣接する二辺がそれぞれ、これらの辺の全長にわたって直線辺に形成された形状の第2プリズムシートとが、それぞれの平坦面を前記導光板側に向けて配置され、前記第1プリズムシートは、前記導光板の出射面上に貼付けられ、前記第2プリズムシートが、前記周縁部を前記フレームの前記シート載置面上に載置して配置されていることを特徴とする請求項10に記載の面光源。   A first prism sheet formed in substantially the same shape as the outer shape of the light guide plate on the light emitting surface side of the light guide plate, and a peripheral portion overhangs the periphery of the light guide plate, and all of the sides or the light emission The second prism sheet having a shape in which one side facing the element arrangement side and two adjacent sides are formed on the straight sides over the entire length of these sides, with each flat surface facing the light guide plate side The first prism sheet is affixed on the light exit surface of the light guide plate, and the second prism sheet is disposed with the peripheral edge placed on the sheet placement surface of the frame. The surface light source according to claim 10.
  12. 前記導光板の出射面と前記第1プリズムシートとの間に、前記第1プリズムシートと略同じ形状に形成された拡散シートが配置され、前記第1プリズムシートは、前記拡散シートを介して前記導光板の出射面上に貼付けられていることを特徴とする請求項11に記載の面光源。   A diffusion sheet formed in substantially the same shape as the first prism sheet is disposed between the exit surface of the light guide plate and the first prism sheet, and the first prism sheet passes through the diffusion sheet. The surface light source according to claim 11, wherein the surface light source is affixed on an emission surface of the light guide plate.
JP2009147845A 2009-06-22 2009-06-22 Surface light source Pending JP2011003506A (en)

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