JP2003007112A - Surface light source - Google Patents
Surface light sourceInfo
- Publication number
- JP2003007112A JP2003007112A JP2001188458A JP2001188458A JP2003007112A JP 2003007112 A JP2003007112 A JP 2003007112A JP 2001188458 A JP2001188458 A JP 2001188458A JP 2001188458 A JP2001188458 A JP 2001188458A JP 2003007112 A JP2003007112 A JP 2003007112A
- Authority
- JP
- Japan
- Prior art keywords
- light
- guide plate
- light guide
- face
- incident
- 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
Links
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】この発明は、液晶表示装置等
に用いられる面光源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 used for liquid crystal display devices and the like.
【０００２】[0002]
【従来の技術】液晶表示装置等に用いられる面光源とし
て、サイドライト型と呼ばれるものがある。2. Description of the Related Art As a surface light source used in a liquid crystal display device or the like, there is one called a side light type.
【０００３】図４および図５は従来のサイドライト型面
光源を示す平面図および側面図であり、この面光源は、
光を取込む入射端面１ａを有し、前記入射端面１ａから
入射した光を導いて前面から出射する導光板と、この導
光板１の側方の前記入射端面１ａに対向させて配置さ
れ、前記入射端面１ａの全長にわたる長さの冷陰極管２
と、前記冷陰極管２からの出射光を前記入射端面１ａに
向けて反射するリフレクタ３とを配置した構成となって
いる。4 and 5 are a plan view and a side view showing a conventional side light type surface light source.
A light guide plate which has an incident end face 1a for taking in light, guides the light incident from the incident end face 1a and emits the light from a front face, and the light guide plate is disposed so as to face the incident end face 1a on the side of the light guide plate 1, Cold cathode fluorescent lamp 2 having a length that extends over the entire length of the incident end face 1a
And a reflector 3 for reflecting the light emitted from the cold cathode fluorescent lamp 2 toward the incident end face 1a.
【０００４】また、図６は従来の他のサイドライト型面
光源を示す平面図であり、この面光源は、前記導光板１
の入射端面１ａに対向させて、ＬＥＤ（発光ダイオー
ド）等からなる複数（図では２つ）の固体発光素子４
を、前記入射端面１ａの長さ方向に沿わせて適当間隔で
並べて配置した構成となっている。FIG. 6 is a plan view showing another conventional side light type surface light source. This surface light source is the light guide plate 1 described above.
A plurality of (two in the figure) solid-state light-emitting elements 4 made up of LEDs (light-emitting diodes) or the like facing the incident end face 1a of
Are arranged side by side at appropriate intervals along the length direction of the incident end face 1a.
【０００５】[0005]
【発明が解決しようとする課題】図４および図５に示し
た従来の面光源は、導光板１の入射端面１ａの全長にわ
たる長さの冷陰極管２を備えたものであるため、この陰
極管２からの出射光を前記導光板１にその入射端面１ａ
の全域から入射させ、前記導光板１の前面から均一な輝
度分布の光を出射することができるが、その反面、前記
冷陰極管３の寿命が短いため、頻繁に冷陰極管３を交換
しなければならず、したがって維持費が嵩むという問題
をもっている。Since the conventional surface light source shown in FIGS. 4 and 5 is provided with the cold cathode tube 2 having the length over the entire length of the incident end face 1a of the light guide plate 1, this cathode is used. The light emitted from the tube 2 is incident on the light guide plate 1 at its incident end face 1a.
It is possible to allow the light to enter from the entire area of the light guide plate 1 and to emit light having a uniform luminance distribution from the front surface of the light guide plate 1. However, on the other hand, since the life of the cold cathode tube 3 is short, the cold cathode tube 3 is frequently replaced. There is a problem in that it must be done and therefore maintenance costs increase.
【０００６】これに対して、図６に示した従来の面光源
は、ＬＥＤ等の固体発光素子４の寿命が半永久的である
ため、発光素子４の交換はほとんど不要であるが、導光
板１への入射光が、前記導光板１の入射端面１ａの長さ
方向に沿わせて適当間隔で並べて配置された複数の固体
発光素子４からの出射光であるため、前記入射端面１ａ
から入射した光が導光板１の全域に均等に行き渡らず、
そのために、導光板１の前面から出射する光のうち、図
６に平行斜線を施して示した領域からの出射光の輝度が
低くて、均一な輝度分布の出射光が得られないという問
題をもっている。On the other hand, in the conventional surface light source shown in FIG. 6, since the solid-state light emitting element 4 such as an LED has a semi-permanent life, it is almost unnecessary to replace the light emitting element 4, but the light guide plate 1 The incident light on the incident end surface 1a of the light guide plate 1 is emitted from a plurality of solid-state light emitting elements 4 arranged at appropriate intervals along the length direction of the incident end surface 1a.
The light incident from does not spread evenly over the entire area of the light guide plate 1,
Therefore, among the lights emitted from the front surface of the light guide plate 1, the brightness of the lights emitted from the region shown by hatching in FIG. 6 is low, and thus the lights having a uniform brightness distribution cannot be obtained. There is.
【０００７】なお、前記固体発光素子４の数を多くし、
この発光素子４を導光板１の入射端面１ａの長さ方向に
沿わせて密な間隔で配置すれば、前記導光板１にその入
射端面１ａの全域から光を入射させ、前記導光板１の前
面から均一な輝度分布の光を出射することができるが、
発光素子数を多くしたのでは、面光源がコスト高になる
とともに、消費電力が増大してしまう。Incidentally, the number of the solid state light emitting elements 4 is increased,
By arranging the light emitting elements 4 along the length direction of the incident end face 1a of the light guide plate 1 at a close interval, light is made incident on the entire light guide plate 1 on the incident end face 1a, and It is possible to emit light with a uniform brightness distribution from the front surface,
Increasing the number of light emitting elements increases the cost of the surface light source and increases the power consumption.
【０００８】この発明は、固体発光素子を備えたサイド
ライト型の面光源として、少ない発光素子数で、導光板
の前面から均一な輝度分布の光を出射することができる
ものを提供することを目的としたものである。The present invention provides a side light type surface light source having a solid-state light emitting element, which can emit light having a uniform luminance distribution from the front surface of the light guide plate with a small number of light emitting elements. It is intended.
【０００９】[0009]
【課題を解決するための手段】この発明の面光源は、対
向する第１と第２の２つの端面と、前記第１の端面から
前記第２の端面に向かって進む光を前側に出射する複数
の出射面が形成された前面とを有する導光板と、前記導
光板の前記第２の端面に対向させて配置された少なくと
も１つの固体発光素子と、前記導光板の前記第１の端面
に設けられ、前記第２の端面から前記導光板に入射して
前記第１の端面に導かれた光を反射する反射手段とを備
えたことを特徴とするものである。The surface light source according to the present invention emits, to the front side, first and second two end faces facing each other and light traveling from the first end face toward the second end face. A light guide plate having a front surface on which a plurality of emission surfaces are formed; at least one solid-state light-emitting element arranged to face the second end surface of the light guide plate; and a first end surface of the light guide plate. And a reflection means for reflecting the light that is provided to the light guide plate from the second end face and is guided to the first end face.
【００１０】この面光源は、前記導光板の第１と第２の
２つの端面のうち、第２の端面に対向させて配置された
固体発光素子からの出射光を、前記導光板に前記第２の
端面から入射させて前記導光板内を前記第１の端面に導
き、この第１の端面に設けられた反射手段により反射さ
れて前記導光板内を前記第２の端面に向かって進ませ、
この光を、前記導光板の前面に形成された複数の出射面
から前側に出射させる。In this surface light source, the light emitted from a solid-state light emitting element, which is arranged facing the second end face of the first and second end faces of the light guide plate, is transmitted to the light guide plate by the first light. The light is introduced from the second end face to guide the inside of the light guide plate to the first end face, and is reflected by the reflection means provided on the first end face to advance inside the light guide plate toward the second end face. ,
This light is emitted to the front side from a plurality of emission surfaces formed on the front surface of the light guide plate.
【００１１】この面光源によれば、前記固体発光素子か
ら出射して前記導光板に前記第２の端面から入射した光
が、前記導光板内を前記第２の端面とは反対側の第１の
端面まで導かれる間に前記導光板の全幅にわたって広が
って前記第１の端面に設けられた反射手段により反射さ
れ、その光が前記導光板内を前記第２の端面に向かって
進みながら前記導光板の前面の複数の出射面から前側に
出射するため、少ない発光素子数で、前記導光板の前面
から均一な輝度分布の光を出射することができる。According to this surface light source, the light emitted from the solid-state light emitting element and incident on the light guide plate from the second end face is in the light guide plate at the first side opposite to the second end face. While being guided to the end surface of the light guide plate, the light guide plate spreads over the entire width of the light guide plate and is reflected by the reflection means provided on the first end face, and the light is guided through the light guide plate toward the second end face. Since light is emitted to the front side from a plurality of emission surfaces on the front surface of the light plate, it is possible to emit light having a uniform luminance distribution from the front surface of the light guide plate with a small number of light emitting elements.
【００１２】この発明の面光源は、上記のように、対向
する第１と第２の２つの端面と、前記第１の端面から前
記第２の端面に向かって進む光を前側に出射する複数の
出射面が形成された前面とを有する導光板を備え、この
導光板の前記第２の端面に対向させて少なくとも１つの
固体発光素子を配置し、前記導光板の前記第１の端面
に、前記第２の端面から前記導光板に入射して前記第１
の端面に導かれた光を反射する反射手段を設けることに
より、少ない発光素子数で、前記導光板の前面から均一
な輝度分布の光を出射することができるようにしたもの
である。As described above, the surface light source according to the present invention emits, to the front side, the two first and second end faces facing each other and the light traveling from the first end face toward the second end face. A light guide plate having a front surface on which an emission surface of is formed, at least one solid-state light-emitting element is arranged facing the second end surface of the light guide plate, and the first end surface of the light guide plate is The light is incident on the light guide plate from the second end face and
By providing a reflecting means for reflecting the light guided to the end face of the light guide plate, it is possible to emit light having a uniform luminance distribution from the front surface of the light guide plate with a small number of light emitting elements.
【００１３】この面光源において、導光板は、その前面
の複数の出射面が、前記導光板の長さ方向に間隔をおい
て形成された複数の細長段差面からなっており、前記導
光板の前面の前記複数の出射面の間の領域がそれぞれ、
隣り合う前記出射面のうちの前記第１の端面側の出射面
の下端と前記第２の端面側の出射面の上端とをつなぐ直
線面状に形成された構成のものが好ましい。In this surface light source, the light guide plate has a plurality of emission surfaces on the front surface thereof, which are formed by a plurality of elongated step surfaces formed at intervals in the length direction of the light guide plate. The area between the plurality of emission surfaces of the front surface,
It is preferable that a linear surface is formed that connects the lower end of the emission surface on the side of the first end face and the upper end of the emission surface on the side of the second end face of the adjacent emission faces.
【００１４】さらに、この面光源おいては、前記導光板
の前面の複数の出射面の間の領域と前記導光板の後面と
のいずれかに、前側からの入射光を反射させるための反
射膜を設けるのが望ましい。Further, in this surface light source, a reflection film for reflecting incident light from the front side on either the region between the plurality of emission surfaces on the front surface of the light guide plate or the rear surface of the light guide plate. Is desirable.
【００１５】また、この面光源において、前記導光板の
第１の端面に設けられた反射手段は、光拡散手段を備え
ているのが好ましい。In this surface light source, it is preferable that the reflecting means provided on the first end surface of the light guide plate includes a light diffusing means.
【００１６】[0016]
【発明の実施の形態】図１はこの発明の第１の実施例を
示す面光源の側面図である。1 is a side view of a surface light source showing a first embodiment of the present invention.
【００１７】この実施例の面光源は、図１に示すよう
に、対向する第１と第２の２つの端面１０ａ，１０ｂ
と、前記第１の端面（図において左側の端面）１０ａか
ら前記第２の端面（図において右側の端面）１０ｂに向
かって進む光を前側に出射する複数の細長出射面１１が
形成された前面１０ｃと、直線面状の後面１０ｄとを有
する導光板１０と、前記導光板１０の第２の端面１０ｂ
に対向させて配置された少なくとも１つの固体発光素子
１３と、前記導光板１０の第１の端面１０ａに設けら
れ、前記第２の端面１０ｂから前記導光板１０に入射し
て前記第１の端面１０ａに導かれた光を反射する反射手
段１４と、前記導光板１０の前側に配置された光学部材
１６とを備えている。As shown in FIG. 1, the surface light source of this embodiment has two opposing first and second end faces 10a and 10b.
And a front surface on which a plurality of elongated emission surfaces 11 for emitting light traveling forward from the first end surface (the left end surface in the drawing) 10a toward the second end surface (the right end surface in the drawing) 10b are formed. 10c, a light guide plate 10 having a linear rear surface 10d, and a second end face 10b of the light guide plate 10.
And at least one solid-state light-emitting element 13 arranged to face each other and the first end face 10a of the light guide plate 10, the second end face 10b being incident on the light guide plate 10 to enter the first end face. The light guide unit 10 includes a reflection unit 14 that reflects the light guided to the light guide unit 10a, and an optical member 16 disposed on the front side of the light guide plate 10.
【００１８】前記導光板１０は、アクリル系樹脂等から
なる透明板であり、この導光板１０の前面１０ｃに形成
された複数の細長出射面１１は、前記導光板１０の長さ
方向に間隔をおいて形成された複数の段差面からなって
おり、前記導光板１０の前面１０ｃの前記複数の細長出
射面１１の間の領域（以下、出射面間領域と言う）はそ
れぞれ、隣り合う前記細長出射面１１のうちの前記第１
の端面１０ａ側の細長出射面１１の下端と前記第２の端
面１０ｂ側の細長出射面１１の上端とをつなぐ直線面状
に形成されている。The light guide plate 10 is a transparent plate made of acrylic resin or the like, and a plurality of elongated emission surfaces 11 formed on the front surface 10c of the light guide plate 10 are spaced in the lengthwise direction of the light guide plate 10. The area between the plurality of elongated emission surfaces 11 of the front surface 10c of the light guide plate 10 (hereinafter, referred to as an inter-emission surface area) is adjacent to each other. The first of the emission surfaces 11
Is formed in a straight line shape connecting the lower end of the elongated emission surface 11 on the side of the end face 10a and the upper end of the elongated emission surface 11 on the side of the second end face 10b.
【００１９】なお、この実施例では、前記導光板１０の
後面１０ｄを平坦面に形成するとともに、前記導光板１
０の前面１０ｃの複数の出射面間領域をそれぞれ、導光
板後面１０ｄと平行で、且つ、各出射面間領域の高さが
前記第１の端面１０ａから前記第２の端面１０ｂに向っ
て順次低くなるように形成しており、したがって、導光
板前面１０ｃの出射面間領域と導光板後面１０ｄとの間
の距離、つまり導光板１０の厚さは、前記第１の端面１
０ａから前記第２の端面１０ｂに向かって段階的に小さ
くなっている。In this embodiment, the rear surface 10d of the light guide plate 10 is formed into a flat surface, and the light guide plate 1 is formed.
The plurality of inter-emission surface areas of the front surface 10c of 0 are parallel to the rear surface 10d of the light guide plate, and the heights of the inter-emission surface areas are sequentially from the first end surface 10a toward the second end surface 10b. Therefore, the distance between the emission surface area of the light guide plate front surface 10c and the light guide plate rear surface 10d, that is, the thickness of the light guide plate 10 is equal to the first end surface 1
It gradually decreases from 0a toward the second end face 10b.
【００２０】そして、前記導光板１０の前面１０ｃの複
数の出射面間領域にはそれぞれ、その全域にわたって反
射膜１２が設けられている。この反射膜１２は、Ａｌ
（アルミニウム）等の金属膜からなっており、前記出射
面間領域に貼付けられるか、あるいは前記出射面間領域
に蒸着またはメッキされている。A reflective film 12 is provided over the entire area of each of the plurality of inter-emission areas on the front surface 10c of the light guide plate 10. This reflective film 12 is made of Al
It is made of a metal film such as (aluminum) and is attached to the area between the emission surfaces or is vapor-deposited or plated in the area between the emission surfaces.
【００２１】また、前記固体発光素子１３は、その構造
は図示しないが、ＬＥＤ（発光ダイオード）を、光拡散
性を有する透明樹脂によりモールドしたものであり、こ
の固体発光素子１３の出射光の色は、面光源の用途に応
じて設定されている。Although not shown, the solid-state light-emitting element 13 is an LED (light-emitting diode) molded with a transparent resin having a light diffusing property. Is set according to the application of the surface light source.
【００２２】すなわち、前記固体発光素子１３は、着色
光を出射するものでも、白色光を出射するものでもよ
く、着色光を出射する固体発光素子は、所定の色の着色
光を発するＬＥＤを前記透明樹脂によりモールドした構
成となっており、白色光を出射する固体発光素子は、赤
色光を発する赤色ＬＥＤと、緑色光を発する緑色ＬＥＤ
と、青色光を発する青色ＬＥＤとを１つずつ並べて配置
し、これらのＬＥＤを前記透明樹脂によりモールドした
構成となっている。That is, the solid-state light-emitting element 13 may emit colored light or white light. The solid-state light-emitting element that emits colored light is an LED that emits colored light of a predetermined color. The solid-state light-emitting element that emits white light has a red LED that emits red light and a green LED that emits green light.
And a blue LED that emits blue light are arranged side by side, and these LEDs are molded by the transparent resin.
【００２３】なお、前記少なくとも１つの固体発光素子
１３は、前記導光板１０の前記第２の端面１０ｂを長さ
方向に均等に分割した分割点付近に、前記導光板１０の
前記第２の端面１０ｂから僅かに離間させ、この第２の
端面１０ｂに対向させて配置されている。The at least one solid-state light emitting element 13 has the second end face of the light guide plate 10 near a dividing point where the second end face 10b of the light guide plate 10 is evenly divided in the length direction. The second end surface 10b is arranged so as to be slightly separated from the second end surface 10b.
【００２４】また、前記導光板１０の第１の端面１０ａ
にその全域にわたって設けられた反射手段１４は、例え
ば、Ａｌ等の金属膜からなる反射膜１５であり、この反
射膜１５は、前記第１の端面１０ａに貼付けられるか、
あるいは前記第１の端面１０ａに蒸着またはメッキされ
ている。The first end face 10a of the light guide plate 10 is also provided.
The reflection means 14 provided over the entire area is a reflection film 15 made of, for example, a metal film such as Al. This reflection film 15 is attached to the first end face 10a,
Alternatively, the first end face 10a is vapor-deposited or plated.
【００２５】一方、前記導光板１０の前側に配置された
光学部材１６は、前記導光板１０の前面１０ｃの複数の
細長出射面１１から出射する光を取り込んでその光を前
側に出射するとともに、前側からの入射光を後側に出射
し、前記導光板１０の前面１０ｃの複数の出射面間領域
に設けられた反射膜１２により反射されて後側から入射
する光を前側に出射する機能をもっている。On the other hand, the optical member 16 disposed on the front side of the light guide plate 10 takes in light emitted from the plurality of elongated emission surfaces 11 of the front surface 10c of the light guide plate 10 and emits the light to the front side. It has a function of emitting incident light from the front side to the rear side, and emitting light incident from the rear side to the front side, which is reflected by the reflection film 12 provided in a plurality of emission surface areas of the front surface 10c of the light guide plate 10. There is.
【００２６】この光学部材１６は、前記導光板１０と同
じ横幅を有し、前面が平坦面とされ、後面に、前記導光
板１０の複数の細長出射面１１から出射する光を取り込
むための複数の横長プリズム部１８が長さ方向に間隔を
おいて所定のピッチで形成されたプリズムシート１７か
らなっている。The optical member 16 has the same width as that of the light guide plate 10, the front surface thereof is a flat surface, and the rear surface thereof has a plurality of portions for taking in light emitted from the plurality of elongated emission surfaces 11 of the light guide plate 10. The horizontally long prism portions 18 are composed of prism sheets 17 formed at a predetermined pitch with a space in the length direction.
【００２７】このプリズムシート１７はアクリル系樹脂
等からなっており、前面は平坦面に形成され、後面は、
前記導光板１０の複数の細長出射面１１の長さ方向（導
光板１０の幅方向）と平行な複数の横長プリズム部１８
が所定のピッチで形成されている。The prism sheet 17 is made of an acrylic resin or the like, has a flat front surface and a rear surface.
A plurality of laterally long prism portions 18 parallel to the length direction (width direction of the light guide plate 10) of the plurality of elongated emission surfaces 11 of the light guide plate 10.
Are formed at a predetermined pitch.
【００２８】そして、前記複数の横長プリズム部１８の
一方の側面は、前記導光板１０の細長出射面１１から出
射する光を取り込む入射面１８ａとされており、他方の
側面が前記入射面１８ａから入射した光を前方に向けて
屈折させる屈折面１８ｂとされている。One side surface of each of the plurality of horizontally long prism portions 18 serves as an incident surface 18a for taking in the light emitted from the elongated light emitting surface 11 of the light guide plate 10, and the other side surface from the incident surface 18a. It is a refracting surface 18b that refracts incident light forward.
【００２９】また、前記プリズムシート１７の後面の前
記複数のプリズム部１８の間の部分はそれぞれ前面側お
よび後面側からの入射光を透過させる入出射面１９とさ
れている。The portions of the rear surface of the prism sheet 17 between the plurality of prism portions 18 are input / output surfaces 19 for transmitting incident light from the front surface side and the rear surface side, respectively.
【００３０】この実施例の面光源は、前記プリズムシー
ト１７の後面の複数の横長プリズム部１８の長さ方向を
前記導光板１０の前面１０ｃの複数の細長出射面１１の
長さ方向と平行にするとともに、前記横長プリズム部１
８の一方の側面である入射面１８ａを前記導光板１０の
細長出射面１１に向き合わせた状態で、前記導光板１０
の前側に配置されている。In the surface light source of this embodiment, the lengthwise direction of the plurality of horizontally long prism portions 18 on the rear surface of the prism sheet 17 is made parallel to the lengthwise direction of the plurality of elongated emission surfaces 11 of the front surface 10c of the light guide plate 10. In addition, the horizontal prism unit 1
8, the light incident surface 18a, which is one side surface of the light guide plate 10, faces the elongated light emitting surface 11 of the light guide plate 10.
It is located on the front side of.
【００３１】なお、前記導光板１０は、その複数の細長
出射面１１の上端を通る仮想の直線が前記プリズムシー
ト１７の複数の横長プリズム部１８の頂部を通る仮想の
直線と平行になるように長さ方向に傾けて配置されてお
り、前記プリズムシート１７は、その後面の複数の横長
プリズム部１８の頂部を前記導光板１０の前面１０ｃの
複数の出射面間領域に設けられた反射膜１２の表面に近
接または一致させて配置されている。The light guide plate 10 is arranged so that an imaginary straight line passing through the upper ends of the plurality of elongated emission surfaces 11 is parallel to an imaginary straight line passing through the tops of the plurality of horizontally long prism portions 18 of the prism sheet 17. The prism sheet 17 is disposed so as to be inclined in the length direction, and the tops of the plurality of laterally long prism parts 18 on the rear surface of the prism sheet 17 are provided in the plurality of inter-emission surface regions of the front surface 10c of the light guide plate 10. Placed close to or in line with the surface of.
【００３２】また、前記プリズムシート１７の複数のプ
リズム部１８は、前記導光板１０の複数の細長出射面１
１のピッチよりも小さいピッチで設けられており、した
がって、前記導光板１０の各細長出射面１１に対してそ
れぞれ、前記プリズムシート１７の横長プリズム部１８
が少なくとも１つ以上対向している。Further, the plurality of prism portions 18 of the prism sheet 17 are provided in the plurality of elongated emission surfaces 1 of the light guide plate 10.
They are provided at a pitch smaller than the pitch of 1. Therefore, the horizontally long prism portion 18 of the prism sheet 17 is provided for each of the elongated emission surfaces 11 of the light guide plate 10.
Are facing at least one or more.
【００３３】この面光源は、前記固体発光素子１３から
の出射光を、前記導光板１０により導いてその前面１０
ｃの複数の細長出射面１１から出射し、その光を前記プ
リズムシート１７の前側に出射するとともに、前記プリ
ズムシート１７の前側から入射した光を、前記導光板１
０の前面１０ｃの複数の細長出射面１１の間の領域にそ
れぞれ設けられた反射膜１２により反射し、その反射光
を前記プリズムシート１７の前側に出射する。This surface light source guides the light emitted from the solid-state light emitting device 13 by the light guide plate 10 and the front surface 10 thereof.
The light emitted from the plurality of elongated emission surfaces 11 of c is emitted to the front side of the prism sheet 17, and the light incident from the front side of the prism sheet 17 is emitted to the light guide plate 1.
The light is reflected by the reflection films 12 provided in the regions between the plurality of elongated emission surfaces 11 of the front surface 10c of 0, and the reflected light is emitted to the front side of the prism sheet 17.
【００３４】この面光源は、例えば、反射表示と透過表
示との両方の表示を行なう反射／透過型液晶表示装置に
用いられるものであり、前記反射／透過型液晶表示装置
は、図１に仮想線（二点鎖線）で示した液晶表示素子３
０の後側に、前記面光源を、前記プリズムシート１７の
前面が前記液晶表示素子３０の後面と平行になるように
配置して構成される。This surface light source is used, for example, in a reflective / transmissive liquid crystal display device that performs both reflective display and transmissive display. The reflective / transmissive liquid crystal display device is shown in FIG. Liquid crystal display element 3 indicated by a line (two-dot chain line)
0, the surface light source is arranged so that the front surface of the prism sheet 17 is parallel to the rear surface of the liquid crystal display element 30.
【００３５】なお、図１では、便宜上、前記導光板１０
の複数の細長出射面１１のピッチと前記プリズムシート
１７の複数の横長プリズム部１８のピッチを大きく誇張
して示しているが、前記プリズムシート１７の複数の横
長プリズム部１８は、前記液晶表示素子３０の画素ピッ
チと同程度のピッチ、あるいはそれよりも小さいピッチ
で形成されており、前記導光板１０の複数の細長出射面
１１は、前記プリズムシート１７の複数の横長プリズム
部１８のピッチに応じて設定されている。In FIG. 1, for convenience, the light guide plate 10 is shown.
The pitch of the plurality of elongated emission surfaces 11 and the pitch of the plurality of laterally elongated prism portions 18 of the prism sheet 17 are greatly exaggerated. However, the plurality of horizontally elongated prism portions 18 of the prism sheet 17 are the liquid crystal display elements. The plurality of elongated emission surfaces 11 of the light guide plate 10 are formed at a pitch similar to or smaller than the pixel pitch of 30 and the pitch of the plurality of horizontally long prism portions 18 of the prism sheet 17. Is set.
【００３６】前記反射／透過型液晶表示装置は、充分な
明るさの外光が得られる環境下では、その使用環境の光
である外光を利用する反射型表示を行ない、充分な明る
さの外光が得られない環境下では、前記面光源からの照
明光を利用する透過型表示を行なうものであり、前記面
光源の固体発光素子１３は、前記透過型表示のときに点
灯される。In the reflection / transmission type liquid crystal display device, under the environment where the outside light having a sufficient brightness is obtained, the reflection type display utilizing the outside light which is the light of the use environment is performed to obtain the sufficient brightness. In an environment where outside light is not obtained, transmissive display is performed using illumination light from the surface light source, and the solid state light emitting element 13 of the surface light source is turned on during the transmissive display.
【００３７】まず、前記反射／透過型液晶表示装置に透
過表示を行なわせるときの前記面光源からの照明光の出
射について説明すると、前記固体発光素子１３から出射
した光は、前記導光板１０にその第２の端面１０ｂから
入射し、導光体前面１０ｃの複数の出射面間領域の反射
膜１２での反射と、導光板後面１０ｄと外気（空気）と
の界面での全反射とを繰り返しながら、前記導光体１０
内を前記第２の端面１０ｂからその反対側の第１の端面
１０ａに向かって導かれる。First, the emission of illumination light from the surface light source when the reflective / transmissive liquid crystal display device is to perform transmissive display will be described. Light emitted from the solid state light emitting element 13 is directed to the light guide plate 10. It is incident from the second end face 10b, and is repeatedly reflected by the reflection film 12 in a plurality of inter-emission surface regions of the light guide front face 10c and total reflection at the interface between the light guide plate rear face 10d and the outside air (air). While the light guide 10
The inside is guided from the second end face 10b toward the opposite first end face 10a.
【００３８】この場合、前記導光板１０の前面１０ｃの
複数の出射面間領域は、導光板後面１０ｄと平行で、且
つ、各出射面間領域の高さが前記第１の端面１０ａから
前記第２の端面１０ｂに向って順次低くなるように形成
されているため、前記導光体１０に前記第２の端面１０
ｂから入射した光は、前記複数の出射面間領域の間の細
長出射面１１に入射してこの出射面１１から漏れること
無く、前記導光板１０内を前記第１の端面１０ａに向か
って導かれる。In this case, the plurality of inter-emission surface areas of the front surface 10c of the light guide plate 10 are parallel to the rear surface 10d of the light guide plate, and the heights of the respective inter-emission surface areas are from the first end surface 10a to the first end surface 10a. The second end face 10 is formed on the light guide 10 since the light guide body 10 is formed so as to be gradually lowered toward the second end face 10b.
The light incident from b is guided to the first end face 10a in the light guide plate 10 without entering the elongated emission faces 11 between the plurality of emission face regions and leaking from the emission faces 11. Get burned.
【００３９】そして、前記導光体１０内を前記第２の端
面１０ｂからその反対側の第１の端面１０ａに向かって
導かれながら導光体１０の幅方向に光束を広げ、前記導
光体１０の全幅にわたる幅の光となって前記第１の端面
１０ａに設けられた反射膜１５に入射し、この反射膜１
５により反射される。Then, while being guided from the second end face 10b toward the first end face 10a on the opposite side in the light guide body 10, the light beam is spread in the width direction of the light guide body 10 and the light guide body is formed. The light having a width over the entire width of 10 is incident on the reflection film 15 provided on the first end face 10a, and this reflection film 1
Reflected by 5.
【００４０】なお、前記導光体１０内を導かれる光のう
ち、導光体１０の側面に向かう光は、前記導光板１０の
側面と外気との界面で全反射して導光板１０内に戻るた
め、導光板１０の側面から光が漏れることはない。Of the light guided in the light guide body 10, the light directed to the side surface of the light guide body 10 is totally reflected at the interface between the side surface of the light guide plate 10 and the outside air and enters the light guide plate 10. Since it returns, light does not leak from the side surface of the light guide plate 10.
【００４１】前記反射膜１５により反射された光は、再
び、導光板前面１０ｃの複数の出射面間領域の反射膜１
２での反射と、導光板後面１０ｄと外気との界面での全
反射とを繰り返しながら前記導光板１０内を前記第２の
端面１０ｂに向かって導かれ、その過程で、導光板前面
１０ｃの複数の細長出射面１１のいずれかに入射し、そ
の細長出射面１１から前側に出射する。The light reflected by the reflection film 15 is again reflected by the reflection film 1 in the area between the plurality of emission surfaces of the front surface 10c of the light guide plate.
2 and the total reflection at the interface between the rear surface 10d of the light guide plate and the outside air are repeatedly guided through the inside of the light guide plate 10 toward the second end face 10b, and in the process, the front surface 10c of the light guide plate 10c is guided. The light is incident on any of the plurality of elongated emission surfaces 11 and emitted from the elongated emission surface 11 to the front side.
【００４２】前記導光板１０の前面１０ｃの複数の細長
出射面１１から前側に出射する光は、上記のように、前
記固体発光素子１３から出射して前記導光板１０にその
第２の端面１０ｂから入射し、前記導光体１０内を導か
れながら前記導光体１０の全幅にわたる幅に光束を広げ
た光であるため、その輝度分布は、前記導光体１０の全
幅、つまり前記細長出射面１１の全長にわたって均一で
ある。The light emitted from the plurality of elongated emission surfaces 11 on the front surface 10c of the light guide plate 10 to the front side is emitted from the solid-state light emitting device 13 and the second end surface 10b of the light guide plate 10 is emitted as described above. Since the light is light that is incident on the light guide body 10 and is guided through the light guide body 10 and has a luminous flux spread over the entire width of the light guide body 10, the luminance distribution thereof is the entire width of the light guide body 10, that is, the elongated emission. It is uniform over the entire length of the surface 11.
【００４３】前記導光板１０の前面１０ｃの複数の細長
出射面１１から出射した光はそれぞれ、前記導光板１０
の前側に配置されたプリズムシート１７の後面の複数の
横長プリズム部１８にその一方の側面である入射面１８
ａから入射し、これらのプリズム部１８の他方の側面で
ある屈折面１８ｂと外気との界面で全反射して前記プリ
ズムシート１７の前面の法線に対する角度が小さくなる
方向に屈折し、前記プリズムシート１７の前側に出射す
る。The light emitted from the plurality of elongated emission surfaces 11 on the front surface 10c of the light guide plate 10 is respectively reflected.
The plurality of horizontally long prism portions 18 on the rear surface of the prism sheet 17 arranged on the front side of the
The light enters from a, is totally reflected at the interface between the refraction surface 18b, which is the other side surface of the prism portion 18, and the outside air, and is refracted in a direction in which the angle with respect to the normal line of the front surface of the prism sheet 17 becomes smaller, The light is emitted to the front side of the sheet 17.
【００４４】上記のように、前記面光源は、前記導光板
１０の第１と第２の２つの端面１０ａ，１０ｂのうち、
第２の端面１０ｂに対向させて配置された固体発光素子
１３からの出射光を、前記導光板１０に前記第２の端面
１０ｂから入射させて前記導光板１０内を前記第１の端
面１０ａに導き、この第１の端面１０ａに設けられた反
射膜１５により反射されて前記導光板１０内を前記第２
の端面１０ｂに向かって進む光を、前記導光板１０の前
面１０ｃに形成された複数の細長出射面１１から前側に
出射し、その光を、前記プリズムシート１７により、こ
のプリズムシート１７の前面の法線に対する角度が小さ
くなる方向に屈折させて前側に出射する。As described above, the surface light source is one of the first and second end surfaces 10a and 10b of the light guide plate 10,
Light emitted from the solid-state light-emitting element 13 arranged so as to face the second end face 10b is made incident on the light guide plate 10 from the second end face 10b so that the inside of the light guide plate 10 is directed to the first end face 10a. The light is guided and reflected by the reflection film 15 provided on the first end face 10a, so that the inside of the light guide plate 10 moves to the second position.
Of the light traveling toward the end face 10b of the light guide plate 10 is emitted to the front side from a plurality of elongated emission faces 11 formed on the front face 10c of the light guide plate 10, and the light is emitted from the front face of the prism sheet 17 by the prism sheet 17. The light is refracted in a direction in which the angle with respect to the normal line becomes smaller, and then emitted to the front side.
【００４５】この面光源によれば、前記固体発光素子１
３から出射して前記導光板１０にその前記第２の端面１
０ｂから入射した光が、前記導光板１０内を前記第２の
端面１０ｂとは反対側の第１の端面１０ａまで導かれる
間に前記導光板１０の全幅にわたって広がって前記第１
の端面１０ａに設けられた反射膜１２により反射され、
その光が前記導光板１０内を前記第２の端面１０ｂに向
かって進みながら前記導光板１０の前面１０ｃの複数の
細長出射面１１から前側に出射するため、前記発光素子
１４を前記導光板１０の第２の端面１０ｂの長さ方向に
密な間隔で配置して前記第２の端面１０ｂの全域から光
を入射させる必要はなく、したがって、少ない発光素子
数で、前記導光板１０の前面１０ｃの複数の細長出射面
１１から均一な輝度分布の光を出射することができる。According to this surface light source, the solid-state light emitting device 1
3 from which the second end surface 1 is emitted to the light guide plate 10.
The light incident from 0b spreads over the entire width of the light guide plate 10 while being guided through the light guide plate 10 to the first end surface 10a opposite to the second end surface 10b.
Is reflected by the reflection film 12 provided on the end surface 10a of
Since the light travels in the light guide plate 10 toward the second end surface 10b and is emitted to the front side from the plurality of elongated emission surfaces 11 of the front surface 10c of the light guide plate 10, the light emitting element 14 is guided to the light guide plate 10. It is not necessary to arrange the second end faces 10b at a close interval in the longitudinal direction to allow light to be incident from the entire area of the second end face 10b, and therefore the front face 10c of the light guide plate 10 can be provided with a small number of light emitting elements. Light having a uniform luminance distribution can be emitted from the plurality of elongated emission surfaces 11.
【００４６】また、この面光源は、前記導光板１０の前
側に前記プリズムシート１７を配置しているため、前記
導光板１０の前面１０ｃに形成された複数の細長出射面
１１から前側に出射した光を、前記プリズムシート１７
により、このプリズムシート１７の前面の法線に対する
角度が小さくなる方向に屈折させて前側に出射すること
ができる。Further, since the prism sheet 17 is arranged on the front side of the light guide plate 10, this surface light source emits light to the front side from a plurality of elongated emission surfaces 11 formed on the front surface 10c of the light guide plate 10. The light is transmitted to the prism sheet 17
Thus, the prism sheet 17 can be refracted in a direction in which the angle with respect to the normal to the front surface of the prism sheet 17 becomes smaller and emitted to the front side.
【００４７】そのため、この面光源によれば、前記固体
発光素子１３からの出射光を、輝度分布が均一で、しか
も正面方向（プリズムシート１７の前面の法線付近の方
向）に指向性をもつ光として出射することができる。Therefore, according to this surface light source, the light emitted from the solid-state light emitting element 13 has a uniform luminance distribution and has directivity in the front direction (direction near the normal to the front surface of the prism sheet 17). It can be emitted as light.
【００４８】そして、前記面光源からの出射光（プリズ
ムシート１７の前側に出射した光）は、前記液晶表示素
子３０にその後側から入射し、この液晶表示素子３０を
透過して画像光となって前側に出射する。The light emitted from the surface light source (the light emitted to the front side of the prism sheet 17) enters the liquid crystal display element 30 from the rear side and is transmitted through the liquid crystal display element 30 to become image light. And emits to the front side.
【００４９】この透過表示のときの表示は、前記面光源
からの出射光が、輝度分布が均一で、しかも正面方向に
指向性をもった光であるため、画面全体の輝度が均一
で、正面輝度の高い表示である。In the case of this transmissive display, since the light emitted from the surface light source has a uniform brightness distribution and has directivity in the front direction, the brightness of the entire screen is uniform and It is a display with high brightness.
【００５０】次に、前記反射／透過型液晶表示装置に外
光を利用する反射型表示を行なわせるときの前記面光源
による入射光の反射について説明すると、この反射表示
のときは、前側から入射した外光が、図１に破矢線で示
したように、前記液晶表示素子３０を透過し、画像光と
なって前記面光源にその前側から入射する。Next, the reflection of the incident light by the surface light source when the reflection / transmission type liquid crystal display device is made to perform the reflection type display utilizing the external light will be explained. In the case of the reflection display, the incident light is incident from the front side. The outside light passes through the liquid crystal display element 30 and becomes image light and enters the surface light source from its front side, as shown by a broken line in FIG.
【００５１】なお、前記反射／透過型液晶表示装置は、
外光を利用する反射型表示のときは、その画面（液晶表
示素子３０の前面）の法線に対して前記画面の上縁側
（図１において左側）に傾いた方向を、最も明るい外光
が得られる方向に向けて使用されるため、最も明るい外
光の入射方向は、前記画面の法線に対して前記画面の上
縁側に傾いた方向である。The reflective / transmissive liquid crystal display device is
In the case of the reflection type display utilizing external light, the brightest external light is directed in a direction inclined to the upper edge side (left side in FIG. 1) of the screen with respect to the normal line of the screen (the front surface of the liquid crystal display element 30). Since it is used toward the obtained direction, the incident direction of the brightest external light is a direction inclined to the upper edge side of the screen with respect to the normal line of the screen.
【００５２】そのため、前記面光源は、前記プリズムシ
ート１７の複数の横長プリズム部１８の長さ方向を前記
液晶表示素子３０の画面の横軸方向と平行にするととも
に、前記横長プリズム部１８の入射面１８ａと屈折面１
８ｂのうち、前記入射面１８ａを前記画面の上縁側に向
け、前記屈折面１８ｂを前記画面の下縁側に向けて配置
されている。Therefore, in the surface light source, the lengthwise direction of the plurality of horizontally long prism portions 18 of the prism sheet 17 is made parallel to the horizontal axis direction of the screen of the liquid crystal display element 30, and the incidence of the horizontally long prism portions 18 is made. Surface 18a and refracting surface 1
8b, the incident surface 18a is arranged to face the upper edge side of the screen, and the refracting surface 18b is arranged to face the lower edge side of the screen.
【００５３】図１に破矢線で示した光の経路は、最も明
るい外光の入射方向（画面の法線に対して前記画面の上
縁側に傾いた方向）から入射した光の経路であり、前側
から入射し、前記液晶表示素子３０を透過して前記面光
源に入射した光は、まず前記プリズムシート１７に入射
し、このプリズムシート１７の後面の複数のプリズム部
１８および各プリズム部１８の間の入出射面１９から出
射して、前記導光板１０の前面１０ｃの出射面間領域に
設けられた反射膜１２により反射される。The light path shown by the broken line in FIG. 1 is the light path that is incident from the direction of the brightest external light incident (the direction inclined to the upper edge side of the screen with respect to the normal to the screen). The light entering from the front side, passing through the liquid crystal display element 30, and entering the surface light source first enters the prism sheet 17, and the plurality of prism portions 18 on the rear surface of the prism sheet 17 and each prism portion 18 are incident. The light is emitted from the incident / emission surface 19 between the reflection surfaces and is reflected by the reflection film 12 provided in the area between the emission surfaces of the front surface 10c of the light guide plate 10.
【００５４】前記反射膜１２により反射された光は、前
記プリズムシート１７の後面の複数の横長プリズム部１
８および各プリズム部１８の間の入出射面１９から入射
し、前記プリズムシート１７の前面の法線に対する角度
が前側から入射した外光の入射角よりも小さくなる方向
に屈折されて、このプリズムシート１７の前面から出射
する。The light reflected by the reflection film 12 is reflected by the plurality of horizontally long prism portions 1 on the rear surface of the prism sheet 17.
8 and each prism portion 18 is refracted in a direction such that the angle with respect to the normal line of the front surface of the prism sheet 17 becomes smaller than the incident angle of external light incident from the front side, and the prism sheet 17 is refracted. The light is emitted from the front surface of the sheet 17.
【００５５】このように、前記面光源は、最も明るい外
光の入射方向から入射し、前記導光板１０の前面１０ｃ
の出射面間領域に設けられた反射膜１２により反射され
た光を、前記プリズムシート１７によりその前面の法線
に対する角度が前側から入射した外光の入射角よりも小
さくなる方向に屈折させて前記プリズムシート１７の前
面から出射するため、前記反射膜１２により反射された
光を、正面方向（プリズムシート１７の前面の法線付近
の方向）に指向性をもつ光として出射することができ
る。As described above, the surface light source enters the brightest external light from the incident direction, and the front surface 10c of the light guide plate 10 is incident.
The light reflected by the reflection film 12 provided in the inter-emission surface area is refracted by the prism sheet 17 in a direction in which the angle with respect to the normal line of the front surface becomes smaller than the incident angle of the external light incident from the front side. Since the light is emitted from the front surface of the prism sheet 17, the light reflected by the reflective film 12 can be emitted as light having directivity in the front direction (direction near the normal to the front surface of the prism sheet 17).
【００５６】しかも、前記面光源は、前記導光板１０の
前面１０ｃの複数の細長出射面１１の間の領域にそれぞ
れその全域にわたって反射膜１２を設けたものであるた
め、連続した一枚膜状の反射板とほとんど変わらない反
射特性をもっており、したがって、前側から入射した光
のほとんど反射し、均一な輝度分布の反射光を出射する
ことができる。Moreover, since the surface light source is provided with the reflective film 12 over the entire area in the area between the plurality of elongated emission surfaces 11 on the front surface 10c of the light guide plate 10, a continuous single film shape is provided. The reflection characteristics are almost the same as those of the reflection plate of (1), and therefore, most of the light incident from the front side is reflected and the reflected light having a uniform luminance distribution can be emitted.
【００５７】そして、前記面光源により反射された光
は、前記液晶表示素子３０にその後側から入射し、この
液晶表示素子３０を透過して前側に出射する。The light reflected by the surface light source enters the liquid crystal display element 30 from the rear side, passes through the liquid crystal display element 30, and is emitted to the front side.
【００５８】この反射表示のときの表示は、前記面光源
が均一な輝度分布の反射光を正面方向に出射するため、
上述した透過表示のときと同様に、画面全体の輝度が均
一で、正面輝度の高い表示である。In this reflective display, the surface light source emits reflected light having a uniform brightness distribution in the front direction.
Similar to the case of the transmissive display described above, the brightness of the entire screen is uniform and the front brightness is high.
【００５９】なお、上記実施例の面光源では、前記固体
発光素子１３から前記導光体１０に入射してこの導光板
１０内を導かれる光のうち、導光体１０の後面１０ｄお
よび側面に向かう光を、前記導光板１０の後面１０ｄお
よび側面と外気との界面で全反射させるようにしている
が、前記導光板１０の後面１０ｄおよび側面に反射膜を
設け、導光体１０の後面１０ｄおよび側面に向かう光を
前記反射膜で反射させるようにしてもよく、このように
することにより、導光板１０の後面１０ｄおよび側面か
らの光の漏れを完全に無くすことができる。In the surface light source of the above-mentioned embodiment, of the light that enters the light guide 10 from the solid-state light emitting element 13 and is guided through the light guide plate 10, the light is guided to the rear surface 10d and the side surface of the light guide 10. The traveling light is totally reflected at the interface between the rear surface 10d and the side surface of the light guide plate 10 and the outside air. However, a reflective film is provided on the rear surface 10d and the side surface of the light guide plate 10, and the rear surface 10d of the light guide body 10 is provided. Alternatively, the light traveling toward the side surface and the side surface may be reflected by the reflective film. By doing so, it is possible to completely eliminate the leakage of the light from the rear surface 10d and the side surface of the light guide plate 10.
【００６０】図２および図３はこの発明の第２の実施例
を示しており、図２は面光源の側面図、図３は導光板の
第１の端面に設けられた反射手段の斜視図である。2 and 3 show a second embodiment of the present invention. FIG. 2 is a side view of a surface light source, and FIG. 3 is a perspective view of a reflecting means provided on a first end face of a light guide plate. Is.
【００６１】この実施例の面光源は、導光板１０の第１
の端面１０ａに、上述した第１の実施例の反射膜１５か
らなる反射手段１４に代えて、光拡散手段を備えた反射
手段２０を設けたものであり、他の構成は第１の実施例
の面光源と同じである。The surface light source according to this embodiment is the first light source of the light guide plate 10.
In place of the reflection means 14 formed of the reflection film 15 of the first embodiment described above, a reflection means 20 having a light diffusion means is provided on the end face 10a of the above, and other configurations are the same as those of the first embodiment. Is the same as the surface light source.
【００６２】この実施例において、前記反射手段２０
は、前記導光板１０の第１の端面１０ａに対向させて配
置された拡散部材２１と、この拡散部材２１の背後に配
置された反射板２２とからなっている。In this embodiment, the reflecting means 20
Is composed of a diffusing member 21 arranged to face the first end face 10 a of the light guide plate 10 and a reflecting plate 22 arranged behind the diffusing member 21.
【００６３】前記拡散部材２１は、例えば図３に示した
ように、アクリル系樹脂等からなる透明シートの一方の
面に、前記導光板１０の第１の端面１０ａの高さ方向に
沿う縦長の円柱面を持った縦長凸レンズ部２１ａを前記
第１の端面１０ａの長さ方向（導光板１０の幅方向）に
並べて形成したレンズシートからなっており、この拡散
部材２１は、前記縦長凸レンズ部２１ａの形成面とは反
対側の平坦面を前記導光板１０の第１の端面１０ａに対
向させて配置され、前記第１の端面１０ａに、図示しな
い粘着剤または両面粘着テープにより貼付けられてい
る。As shown in FIG. 3, for example, the diffusing member 21 has a vertically long shape along the height direction of the first end surface 10a of the light guide plate 10 on one surface of a transparent sheet made of acrylic resin or the like. The diffusing member 21 includes a vertically long convex lens portion 21a having a cylindrical surface and is arranged in the length direction of the first end surface 10a (width direction of the light guide plate 10). The flat surface on the side opposite to the surface on which is formed is disposed so as to face the first end surface 10a of the light guide plate 10, and the first end surface 10a is attached to the first end surface 10a with an adhesive or a double-sided adhesive tape (not shown).
【００６４】また、前記反射板２２は、アルミニウム等
の金属板からなっており、この反射板２２は、前記拡散
部材２１の背後に、この拡散部材２１の複数の縦長凸レ
ンズ部２１ａから僅かに離間させて配置され、図示しな
い支持手段により支持されている。The reflector 22 is made of a metal plate such as aluminum, and the reflector 22 is slightly behind the diffusing member 21 from the plurality of vertically long convex lens portions 21a of the diffusing member 21. And is supported by a support means (not shown).
【００６５】この実施例の面光源は、上記のように、前
記導光板１０の前記第１の端面１０ａに、前記拡散部材
２１と反射板２２とからなる反射手段２０を設けたもの
であるため、固体発光素子１３から出射して導光板１０
に第２の端面１０ｂから入射し、前記導光板１０内をそ
の幅方向に光束を広げながら反対側の第１の端面１０ａ
まで導かれて前記反射手段２０により反射される光を、
前記拡散部材２１により前記導光板１０の幅方向に拡散
することができる。As described above, the surface light source of this embodiment is provided with the reflecting means 20 including the diffusing member 21 and the reflecting plate 22 on the first end face 10a of the light guide plate 10. The light guide plate 10 is emitted from the solid state light emitting device 13.
From the second end face 10b to the first end face 10a on the opposite side while spreading the light flux in the light guide plate 10 in the width direction thereof.
The light that is guided up to and reflected by the reflecting means 20,
The diffusion member 21 can diffuse the light in the width direction of the light guide plate 10.
【００６６】そのため、この実施例の面光源によれば、
前記導光板１０の複数の細長出射面１１から、上記第１
の実施例よりもさらに輝度分布が均一な光を出射するこ
とができる。Therefore, according to the surface light source of this embodiment,
From the plurality of elongated emission surfaces 11 of the light guide plate 10, the first
It is possible to emit light having a more uniform luminance distribution than in the above embodiment.
【００６７】なお、この実施例では、前記反射手段２０
の拡散部材２１を、一方の面に前記導光板１０の第１の
端面１０ａの高さ方向に沿う複数の縦長凸レンズ部２１
ａを前記第１の端面１０ａの長さ方向に並べて形成した
レンズシートとしているが、前記拡散部材２１は、前記
導光板１０の第１の端面１０ａの高さ方向に沿う複数の
縦長プリズム部を前記第１の端面１０ａの長さ方向に並
べて形成したプリズムシートや、あるいは複数の角錐状
プリズムを前記導光板１０の第１の端面１０ａの長さ方
向および高さ方向に並べて形成したプリズムシート等で
もよい。In this embodiment, the reflecting means 20 is used.
A plurality of vertically-elongated convex lens portions 21 on one surface of the diffusing member 21 along the height direction of the first end surface 10a of the light guide plate 10.
Although a is a lens sheet formed by arranging a in the length direction of the first end face 10a, the diffusing member 21 includes a plurality of vertically long prism portions along the height direction of the first end face 10a of the light guide plate 10. A prism sheet formed by arranging in the length direction of the first end surface 10a, or a prism sheet formed by arranging a plurality of pyramidal prisms in the length direction and the height direction of the first end surface 10a of the light guide plate 10 and the like. But it's okay.
【００６８】さらに、前記反射手段２０の拡散手段は、
前記拡散部材２１に限らず、前記導光板１０の第１の端
面１０ａを前記レンズシートまたはプリズムシート等と
同様な凹凸面に形成することにより、前記導光板１０に
一体に形成してもよい。Further, the diffusing means of the reflecting means 20 is
Not only the diffusion member 21 but also the first end surface 10a of the light guide plate 10 may be formed integrally with the light guide plate 10 by forming an uneven surface similar to the lens sheet or the prism sheet.
【００６９】また、上記第１および第２の実施例の面光
源では、導光板１０の前面１０ｃの複数の細長出射面１
１の間の領域に反射膜１２を設けているが、この反射膜
１２を省略し、前記導光板１０の後面１０ｄに、前側か
らの入射光を反射させるための反射膜を設けてもよい。In the surface light sources of the first and second embodiments, the plurality of elongated emission surfaces 1 on the front surface 10c of the light guide plate 10 are used.
Although the reflective film 12 is provided in the region between the two, the reflective film 12 may be omitted and a reflective film for reflecting incident light from the front side may be provided on the rear surface 10d of the light guide plate 10.
【００７０】なお、このように導光板１０の前面１０ｃ
の複数の細長出射面１１の間の領域の反射膜１２を省略
しても、前記導光板１０の第２の端面１０ｂから入射し
た光および前記導光板１０の第１の端面１０ａにおいて
反射手段１４，２０により反射された光を、前記導光板
１０の前面１０ｃの出射面間領域と外気との界面で全反
射させて前記導光板１０内を導くことができる。The front surface 10c of the light guide plate 10 is
Even if the reflective film 12 in the region between the plurality of elongated emission surfaces 11 is omitted, the light incident from the second end face 10b of the light guide plate 10 and the reflection means 14 at the first end face 10a of the light guide plate 10 are omitted. , 20 can be totally reflected at the interface between the emission surface area of the front surface 10c of the light guide plate 10 and the outside air to be guided through the light guide plate 10.
【００７１】さらに、前記導光板１０は、その前面に前
記第１の端面１０ａから前記第２の端面１０ｂに向かっ
て進む光を前側に出射する複数の出射面が形成されたも
のであれば、上記実施例の形状のものに限られるもので
はなく、また、前記導光板１０の第２の端面１０ｂに対
向させて配置する固体発光素子１３は、ＬＥＤに限ら
ず、ＥＬ（エレクトロルミネッセンス）等からなるもの
でもよい。Furthermore, if the light guide plate 10 is provided with a plurality of emission faces for emitting the light traveling from the first end face 10a toward the second end face 10b to the front side on the front surface thereof, It is not limited to the shape of the above embodiment, and the solid state light emitting element 13 arranged facing the second end surface 10b of the light guide plate 10 is not limited to an LED but may be an EL (electroluminescence) or the like. It may be
【００７２】また、前記導光板１０の前側に配置する光
学部材１６は、上記実施例のプリズムシート１７に限ら
ず、前記導光板１０の前面１０ｃの複数の出射面１１か
ら出射する光を取り込んでその光を前側に出射するとと
もに、前側からの入射光を後側に出射し、前記導光板１
０の前面１０ｃの出射面間領域に設けられた反射膜１２
（または導光板１０の後面１０ｄに設けられた前側から
の入射光を反射させるための反射膜）により反射されて
後側から入射する光を前側に出射する機能をもつもので
あればよい。Further, the optical member 16 arranged on the front side of the light guide plate 10 is not limited to the prism sheet 17 of the above-mentioned embodiment, and takes in light emitted from the plurality of emission surfaces 11 of the front surface 10c of the light guide plate 10. The light is emitted to the front side and the incident light from the front side is emitted to the rear side, and the light guide plate 1
The reflective film 12 provided in the area between the emission surfaces of the front surface 10c of 0.
(Or a light reflection plate for reflecting incident light from the front side provided on the rear surface 10d of the light guide plate 10) may be used as long as it has a function of emitting the light incident from the rear side to the front side.
【００７３】さらに、この発明の面光源は、液晶表示装
置に限らず、他の用途にも広く使用することができるも
のであり、その場合、前記導光板１０の前面１０ｃの複
数の出射面１１からの出射光および前記反射膜１２によ
り反射された反射光の向きに指向性をもたせる必要が無
いときは、上記実施例において前記導光板１０の前側に
配置している光学部材１６を省略してもよい。Further, the surface light source of the present invention can be widely used not only for the liquid crystal display device but also for other purposes. In that case, the plurality of emission surfaces 11 of the front surface 10c of the light guide plate 10 are used. When it is not necessary to give directivity to the direction of the light emitted from the light and the direction of the reflected light reflected by the reflective film 12, the optical member 16 disposed on the front side of the light guide plate 10 in the above embodiment is omitted. Good.
【００７４】[0074]
【発明の効果】この発明の面光源は、対向する第１と第
２の２つの端面と、前記第１の端面から前記第２の端面
に向かって進む光を前側に出射する複数の出射面が形成
された前面とを有する導光板と、前記導光板の前記第２
の端面に対向させて配置された少なくとも１つの固体発
光素子と、前記導光板の前記第１の端面に設けられ、前
記第２の端面から前記導光板に入射して前記第１の端面
に導かれた光を反射する反射手段とを備えたものである
ため、少ない発光素子数で、前記導光板の前面から均一
な輝度分布の光を出射することができる。The surface light source of the present invention has two opposing first and second end faces and a plurality of emission faces for emitting the light traveling from the first end face toward the second end face to the front side. A light guide plate having a front surface on which the second surface of the light guide plate is formed.
At least one solid-state light-emitting element that is arranged to face the end surface of the light guide plate, and the first end surface of the light guide plate, the second end surface is incident on the light guide plate and guided to the first end surface. Since it is provided with a reflecting means for reflecting the emitted light, it is possible to emit light having a uniform luminance distribution from the front surface of the light guide plate with a small number of light emitting elements.
【００７５】この面光源において、前記導光板は、その
前面の複数の出射面が、前記導光板の長さ方向に間隔を
おいて形成された複数の細長段差面からなっており、前
記導光板の前面の前記複数の出射面の間の領域がそれぞ
れ、隣り合う前記出射面のうちの前記第１の端面側の出
射面の下端と前記第２の端面側の出射面の上端とをつな
ぐ直線面状に形成された構成のものが好ましく、このよ
うにすることにより、前記導光板に前記第２の端面から
入射した光を前記出射面から漏れさせること無く前記第
１の端面１０ａに導き、前記反射手段により反射されて
前記第１の端面から前記第２の端面に向かって進む光を
前記出射面から前側に出射することができる。In this surface light source, the light guide plate has a plurality of emission surfaces on the front surface thereof, which are composed of a plurality of elongated step surfaces formed at intervals in the length direction of the light guide plate. A region between the plurality of emission surfaces on the front surface of the straight line connecting the lower end of the emission surface on the side of the first end face and the upper end of the emission surface on the side of the second end face of the adjacent emission surfaces. It is preferable that the structure is formed in a planar shape, and by doing so, the light incident on the light guide plate from the second end surface is guided to the first end surface 10a without leaking from the emission surface, Light reflected by the reflecting means and traveling from the first end surface toward the second end surface can be emitted from the emission surface to the front side.
【００７６】さらに、この面光源おいては、前記導光板
の前面の複数の出射面の間の領域と前記導光板の後面と
のいずれかに、前側からの入射光を反射させるための反
射膜を設けるのが望ましく、このようにすることによ
り、前記固体発光素子からの出射光を前側に出射するだ
けでなく、前側からの入射光を前側に反射することがで
きる。Further, in this surface light source, a reflection film for reflecting incident light from the front side on either the region between the plurality of emission surfaces on the front surface of the light guide plate or the rear surface of the light guide plate. Is preferably provided. By doing so, not only the light emitted from the solid-state light-emitting element can be emitted to the front side, but also the incident light from the front side can be reflected to the front side.
【００７７】また、この面光源において、前記導光板の
第１の端面に設けられた反射手段は、光拡散手段を備え
ているのが好ましく、このようにすることにより、さら
に均一な輝度分布の光を出射することができる。Further, in this surface light source, it is preferable that the reflecting means provided on the first end face of the light guide plate is provided with a light diffusing means. By doing so, a more uniform luminance distribution can be obtained. Light can be emitted.
【図１】この発明の第１の実施例を示す面光源の平面
図。FIG. 1 is a plan view of a surface light source showing a first embodiment of the present invention.
【図２】この発明の第２の実施例を示す面光源の平面
図。FIG. 2 is a plan view of a surface light source showing a second embodiment of the present invention.
【図３】第２の実施例の導光板の第１の端面に設けられ
た反射手段の斜視図。FIG. 3 is a perspective view of a reflecting means provided on a first end surface of a light guide plate according to a second embodiment.
【図４】従来の面光源の平面図。FIG. 4 is a plan view of a conventional surface light source.
【図５】前記従来の面光源の側面図。FIG. 5 is a side view of the conventional surface light source.
【図６】従来の他の面光源の平面図。FIG. 6 is a plan view of another conventional surface light source.
１０…導光板 １０ａ…第１の端面 １０ｂ…第２の端面 １０ｃ…前面 １０ｄ…後面 １１…出射面 １２…反射膜 １３…固体発光素子 １４，２０…反射手段 １５…反射膜 ２１…拡散部材 ２２…反射板 １６…光学部材 １７…プリズムシート 10 ... Light guide plate 10a ... first end face 10b ... second end face 10c ... Front 10d ... rear surface 11 ... Emitting surface 12 ... Reflective film 13 ... Solid-state light-emitting element 14, 20 ... Reflecting means 15 ... Reflective film 21 ... Diffusing member 22 ... Reflector 16 ... Optical member 17 ... Prism sheet
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｇ０２Ｆ 1/13357 Ｇ０２Ｆ 1/13357 // Ｆ２１Ｙ 101:02 Ｆ２１Ｙ 101:02 ─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. 7 Identification code FI theme code (reference) G02F 1/13357 G02F 1/13357 // F21Y 101: 02 F21Y 101: 02
Claims (4)
第１の端面から前記第２の端面に向かって進む光を前側
に出射する複数の出射面が形成された前面とを有する導
光板と、 前記導光板の前記第２の端面に対向させて配置された少
なくとも１つの固体発光素子と、 前記導光板の前記第１の端面に設けられ、前記第２の端
面から前記導光板に入射して前記第１の端面に導かれた
光を反射する反射手段とを備えたことを特徴とする面光
源。1. A first and a second end surface facing each other, and a front surface on which a plurality of emission surfaces for emitting light traveling from the first end surface toward the second end surface to the front side are formed. A light guide plate having; at least one solid-state light-emitting element arranged to face the second end face of the light guide plate; provided on the first end face of the light guide plate; and guiding the light from the second end face. A surface light source, comprising: a reflection unit that reflects light that is incident on the light plate and is guided to the first end face.
板の長さ方向に間隔をおいて形成された複数の細長段差
面からなっており、前記導光板の前面の前記複数の出射
面の間の領域がそれぞれ、隣り合う前記出射面のうちの
第１の端面側の出射面の下端と第２の端面側の出射面の
上端とをつなぐ直線面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。2. A plurality of emission surfaces on the front surface of the light guide plate are composed of a plurality of elongated step surfaces formed at intervals in the length direction of the light guide plate, and the plurality of emission surface surfaces on the front surface of the light guide plate. Each of the regions between the emission surfaces is formed in a linear surface shape that connects the lower end of the emission surface on the first end face side and the upper end of the emission surface on the second end face side of the adjacent emission faces. The surface light source according to claim 1, wherein:
前記導光板の後面とのいずれかに、前側からの入射光を
反射させるための反射膜が設けられていることを特徴と
する請求項２に記載の面光源。3. A reflection film for reflecting incident light from the front side is provided on either the region between a plurality of emission surfaces on the front surface of the light guide plate or the rear surface of the light guide plate. The surface light source according to claim 2.
は、光拡散手段を備えていることを特徴とする請求項１
〜３のいずれかに記載の面光源。4. The reflecting means provided on the first end face of the light guide plate comprises a light diffusing means.
The surface light source according to any one of to 3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001188458A JP2003007112A (en) | 2001-06-21 | 2001-06-21 | Surface light source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001188458A JP2003007112A (en) | 2001-06-21 | 2001-06-21 | Surface light source |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2003007112A true JP2003007112A (en) | 2003-01-10 |
Family
ID=19027557
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001188458A Pending JP2003007112A (en) | 2001-06-21 | 2001-06-21 | Surface light source |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2003007112A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20140086082A (en) * | 2012-12-28 | 2014-07-08 | 엘지디스플레이 주식회사 | Led package and back light unit having the same |
| JP2017225125A (en) * | 2010-11-19 | 2017-12-21 | リアルディー スパーク エルエルシー | Directional display device |
| WO2020093945A1 (en) * | 2018-11-09 | 2020-05-14 | 深圳Tcl新技术有限公司 | Side edge reflecting plate attaching process of light guide plate and light guide plate |
-
2001
- 2001-06-21 JP JP2001188458A patent/JP2003007112A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2017225125A (en) * | 2010-11-19 | 2017-12-21 | リアルディー スパーク エルエルシー | Directional display device |
| KR20140086082A (en) * | 2012-12-28 | 2014-07-08 | 엘지디스플레이 주식회사 | Led package and back light unit having the same |
| KR102024646B1 (en) | 2012-12-28 | 2019-09-24 | 엘지디스플레이 주식회사 | Led package and back light unit having the same |
| WO2020093945A1 (en) * | 2018-11-09 | 2020-05-14 | 深圳Tcl新技术有限公司 | Side edge reflecting plate attaching process of light guide plate and light guide plate |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6805468B2 (en) | Surface light source device and liquid crystal display device using it | |
| JP4273002B2 (en) | Compact lighting system and display device | |
| JP4263611B2 (en) | Compact lighting system and display device | |
| US8152320B2 (en) | Surface light source device | |
| JP5475684B2 (en) | Lighting system, lighting fixture and backlight unit | |
| KR100810806B1 (en) | Illumination system, light mixing chamber and display device | |
| US7527411B2 (en) | Lightguide plate of a double-sided illumination backlight and a double-sided liquid crystal display unit using the backlight | |
| US20070263383A1 (en) | Illumination System | |
| WO2009125618A1 (en) | Light emitting device | |
| US8118467B2 (en) | Light guide plate and edge-lighting type backlight module | |
| JP4165579B2 (en) | Light source device, display device | |
| JP2008305923A (en) | Light-emitting device, surface light source device, and image display device | |
| JP2001312916A (en) | Surface light source device | |
| JP2000048618A (en) | Illumination panel and display device using it | |
| JP2004171947A (en) | Backlight device | |
| JP4622787B2 (en) | Backlight system and liquid crystal display device | |
| KR100664373B1 (en) | Backlight panel employing white light emitting diode | |
| JP4096540B2 (en) | Surface light source | |
| KR100855490B1 (en) | Backlight Unit | |
| JP4135402B2 (en) | Surface light source | |
| WO2012133118A1 (en) | Lighting device and display device | |
| JP2003007112A (en) | Surface light source | |
| JP2004119143A (en) | Surface light source | |
| JP2011198479A (en) | Surface light source and liquid crystal display device | |
| JP3889958B2 (en) | Surface light emitter and liquid crystal display device |