JP2012164435A - Planar light source device and liquid crystal display - Google Patents

Planar light source device and liquid crystal display Download PDF

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JP2012164435A
JP2012164435A JP2011021903A JP2011021903A JP2012164435A JP 2012164435 A JP2012164435 A JP 2012164435A JP 2011021903 A JP2011021903 A JP 2011021903A JP 2011021903 A JP2011021903 A JP 2011021903A JP 2012164435 A JP2012164435 A JP 2012164435A
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light
guide plate
source device
light source
incident
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JP5375845B2 (en
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Kenji Itoga
賢二 糸賀
Naoko Iwasaki
直子 岩崎
Akimasa Yuki
昭正 結城
Tetsuya Satake
徹也 佐竹
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Mitsubishi Electric Corp
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Abstract

PROBLEM TO BE SOLVED: To obtain a planar light source device, in which light incident into a light guide plate is dispersed, and is reduced in brightness unevenness.SOLUTION: The planar light source device 100a is provided with LEDs 1 as point light sources and a light guide plate 2 into which light emitted from the LEDs 1 is incident. The LEDs 1 are arranged in the vicinity of an incident face 2c of the light guide plate 2, and the light guide plate 2 is to make light incident from the incident face 2c emitted in plane from an emission face 2a nearly crossing the incident face 2c as well as an anti-incident face 2d. A light-diffusing face 22a, provided in the vicinity of the incident face 2c inside the light guide plate 2, is formed in a direction vertical to the emission face 2a, and that, two conical faces as concave faces facing the incident face 2c are coupled with each other at a center position of the LEDs 1.

Description

この発明は、面光源装置およびこの面光源装置を備えた液晶表示装置に関する。   The present invention relates to a surface light source device and a liquid crystal display device including the surface light source device.

液晶表示装置等の非発光表示装置に用いられる面光源装置として、導光板と、この導光板の端面に沿って一列に配列された複数のＬＥＤ（発光ダイオード）とを備え、端面から入射された光が導光板の出光面から面状に出射されるものが知られている。   As a surface light source device used for a non-light emitting display device such as a liquid crystal display device, the light source plate includes a light guide plate and a plurality of LEDs (light emitting diodes) arranged in a line along the end surface of the light guide plate, and is incident from the end surface One in which light is emitted in a planar shape from a light exit surface of a light guide plate is known.

このような面光源装置においては、光源であるＬＥＤが指向性を有するため、導光板の出光面から出射される光に輝度ムラが生じてしまうという問題がある。このため従来の面光源装置においては、導光板の端面のＬＥＤと対向する部分を曲面に形成するとともに、この曲面の両側に階段状の傾斜面を形成し、導光板の上記曲面に対向する位置にその頂角が上記曲面と対向する三角柱状の孔を形成していた。この構成によれば、ＬＥＤから出射された光は上記曲面で平行化された後、上記三角柱状の孔で上記傾斜面に向かって反射され、この傾斜面で導光板の端面に垂直な方向に向かって反射されるので、導光板の端面に平行な方向の光の量が増加し輝度ムラが少なくなる（例えば、特許文献１参照）。   In such a surface light source device, since the LED as the light source has directivity, there is a problem that luminance unevenness occurs in the light emitted from the light exit surface of the light guide plate. For this reason, in the conventional surface light source device, a portion facing the LED on the end face of the light guide plate is formed into a curved surface, and a stepped inclined surface is formed on both sides of the curved surface, and the position facing the curved surface of the light guide plate In addition, a triangular prism-shaped hole whose apex angle faces the curved surface was formed. According to this configuration, the light emitted from the LED is collimated by the curved surface and then reflected by the triangular prism-shaped hole toward the inclined surface, and the inclined surface is perpendicular to the end surface of the light guide plate. Therefore, the amount of light in the direction parallel to the end face of the light guide plate is increased, and the luminance unevenness is reduced (see, for example, Patent Document 1).

特開２００４―１９２９３７号公報JP 2004-192937 A

上記の面光源装置において、三角柱状の孔や傾斜面が設けられた領域である導入部は発光領域として使用することができないデッドスペースであるため、近年では、この導入部を狭小化して発光領域を拡大することが要求されている。これに加えて、各ＬＥＤ間の間隔を広げてＬＥＤの使用個数を低減することも要求されており、これら２つの要求から導入部の幅に対するＬＥＤ間隔の比率を大きくすることが課題となっている。しかしながら、上記の従来技術では端面の形状が複雑であるので、導入部の幅に対するＬＥＤ間隔の比率を大きくすると輝度ムラが抑制できないという問題点があった。   In the above surface light source device, since the introduction portion, which is a region provided with a triangular prism-shaped hole or an inclined surface, is a dead space that cannot be used as a light emission region, in recent years, the introduction portion has been reduced to a light emission region. Is required to expand. In addition to this, it is also required to increase the interval between the LEDs to reduce the number of LEDs used. From these two requirements, it becomes a problem to increase the ratio of the LED interval to the width of the introduction portion. Yes. However, since the shape of the end face is complicated in the above prior art, there is a problem that luminance unevenness cannot be suppressed if the ratio of the LED interval to the width of the introduction portion is increased.

この発明は、上述のような点に着目してなされたもので、輝度ムラの少ない面光源装置を得ることを目的とする。   The present invention has been made paying attention to the above-described points, and an object thereof is to obtain a surface light source device with less luminance unevenness.

この発明に係る面光源装置においては、点光源と、点光源から出射された光が入射される導光板とを備え、点光源は、導光板の一方の端面に近接して配置され、導光板は、一方の端面から入射した光を、一方の端面および一方の端面に対向する他方の端面に対し略直交する出光面から面状に出射させるようにした面光源装置において、導光板内の一方の端面近傍に光拡散面が設けられ、光拡散面は、出光面に垂直な方向に形成され、かつ一方の端面に臨む凹面である２つの円弧面が、点光源の中心位置で連結して構成されていることを特徴とするものである。   The surface light source device according to the present invention includes a point light source and a light guide plate on which light emitted from the point light source is incident. The point light source is disposed close to one end surface of the light guide plate, Is a surface light source device in which light incident from one end surface is emitted in a planar shape from a light exit surface substantially orthogonal to one end surface and the other end surface opposed to the one end surface. A light diffusing surface is provided in the vicinity of the end surface of the light source. The light diffusing surface is formed in a direction perpendicular to the light emitting surface, and two circular arc surfaces that are concave surfaces facing one end surface are connected at the center position of the point light source. It is characterized by being comprised.

この発明に係る面光源装置得によれば、導光板の一方の端面近傍に、出光面に垂直な方向に形成され、かつ入光面を臨む凹面である２つの円弧面が点光源の中心位置で連結した形状の光拡散面を設けたことにより、導光板内に入射した光が拡散され、輝度ムラが少なくなる。   According to the surface light source device according to the present invention, the two arcuate surfaces that are formed in the direction perpendicular to the light exit surface in the vicinity of one end surface of the light guide plate and that face the light incident surface are the center positions of the point light sources. By providing the light diffusing surface having a shape connected with, the light incident on the light guide plate is diffused and the luminance unevenness is reduced.

実施の形態１に係る面光源装置の斜視図を示す。1 is a perspective view of a surface light source device according to Embodiment 1. FIG. 実施の形態１に係る面光源装置において導光板の入光面近傍の一部を示す上面図である。FIG. 3 is a top view showing part of the vicinity of the light incident surface of the light guide plate in the surface light source device according to Embodiment 1; 実施の形態１に係る面光源装置において図２に示す導光板の光拡散面を拡大して示す上面図である。3 is an enlarged top view showing a light diffusion surface of the light guide plate shown in FIG. 2 in the surface light source device according to Embodiment 1. FIG. 図３のＡＡ線に沿って示す断面図である。FIG. 4 is a cross-sectional view taken along line AA in FIG. 3. 比較例の面光源装置において導光板の光拡散面を拡大して示す上面図である。It is a top view which expands and shows the light-diffusion surface of a light-guide plate in the surface light source device of a comparative example. 図５のＢＢ線に沿って示す断面図である。It is sectional drawing shown along BB line of FIG. 実施の形態１に係る面光源装置の導光板内部の相対輝度分布を示す特性図である。It is a characteristic view which shows the relative luminance distribution inside the light-guide plate of the surface light source device which concerns on Embodiment 1. FIG. 実施の形態２に係る面光源装置において導光板の光拡散面を拡大して示す上面図である。FIG. 6 is an enlarged top view showing a light diffusion surface of a light guide plate in a surface light source device according to Embodiment 2. 図８のＤＤ線に沿って示す断面図である。It is sectional drawing shown along the DD line of FIG. 実施の形態３に係る面光源装置において導光板の出光面側の光拡散面を拡大して示す上面図である。FIG. 9 is an enlarged top view showing a light diffusing surface on a light exit surface side of a light guide plate in a surface light source device according to Embodiment 3. 実施の形態３に係る面光源装置において導光板の反出光面側の光拡散面を拡大して示す上面図である。FIG. 10 is an enlarged top view showing a light diffusion surface on the side of the light exit surface of the light guide plate in the surface light source device according to Embodiment 3. 図１０および図１１のＥＥ線に沿って示す断面図である。It is sectional drawing shown along the EE line | wire of FIG. 10 and FIG. 実施の形態４に係る面光源装置の導光板の光拡散面を拡大して示す上面図である。It is a top view which expands and shows the light-diffusion surface of the light-guide plate of the surface light source device which concerns on Embodiment 4. 実施の形態５に係る面光源装置の導光板の光拡散面を拡大して示す上面図である。It is a top view which expands and shows the light-diffusion surface of the light-guide plate of the surface light source device which concerns on Embodiment 5. FIG. 実施の形態６に係る面光源装置の導光板の光拡散面を拡大して示す上面図である。It is a top view which expands and shows the light-diffusion surface of the light-guide plate of the surface light source device which concerns on Embodiment 6. FIG. 実施の形態７に係る面光源装置の導光板の光拡散面を拡大して示す上面図である。It is a top view which expands and shows the light-diffusion surface of the light-guide plate of the surface light source device which concerns on Embodiment 7. 実施の形態１に係る液晶表示装置の斜視図を示す。1 is a perspective view of a liquid crystal display device according to Embodiment 1. FIG.

実施の形態１．
図１ないしは図４は、実施の形態１に係る面光源装置を示すものであって、図１（ａ）は面光源装置を示す斜視図、図１（ｂ）は面光源装置の導光板を示す斜視図、図２は導光板の入光面近傍を示す上面図、図３は図２に示す導光板の光拡散面を拡大して示す上面図、図４は図３のＡＡ線に沿って示す断面図である。また、図５および図６は、比較例の面光源装置を示すものであって、図５は導光板の光拡散面を拡大して示す上面図、図６は図５のＢＢ線に沿って示す断面図である。また、図７は実施の形態１に係る面光源装置の導光板内部の相対輝度分布を示す特性図である。 Embodiment 1 FIG.
1 to 4 show the surface light source device according to Embodiment 1, in which FIG. 1A is a perspective view showing the surface light source device, and FIG. 1B is a light guide plate of the surface light source device. 2 is a top view showing the vicinity of the light incident surface of the light guide plate, FIG. 3 is an enlarged top view showing the light diffusion surface of the light guide plate shown in FIG. 2, and FIG. 4 is along the line AA in FIG. FIG. 5 and 6 show a surface light source device of a comparative example, in which FIG. 5 is an enlarged top view showing the light diffusion surface of the light guide plate, and FIG. 6 is taken along line BB in FIG. It is sectional drawing shown. FIG. 7 is a characteristic diagram showing a relative luminance distribution inside the light guide plate of the surface light source device according to the first embodiment.

面光源装置１００ａは、図１（ａ）および図１（ｂ）に示すように、点光源である３個のＬＥＤ１と、このＬＥＤ１から出射された光が入射される導光板２とを備えている。ＬＥＤ１は導光板２の一方の端面（以下、入光面２ｃと称する）に近接して配置されており、入光面２ｃから他方の端面（以下、反入光面２ｄと称する）に向かって入射するＬＥＤ１の光が入光面２ｃおよび反入光面２ｄに略直交する出光面２ａから面状に出射される。また、面光源装置１００ａは、出光面２ａの入光面２ｃ近傍、入光面２ｃおよび反出光面２ｂを覆うように配置された反射板３と、出光面２ａ上に配置され、導光板２からの光を均等に拡散する拡散板４とを備えている。さらに、面光源装置１００ａは、拡散板４上に配置され、拡散板４を通過した光を集めて方向を変える縦プリズムシート５と、縦プリズムシート５上に配置され、縦プリズムシート５を通過した光を集めて方向を変える横プリズムシート６とを備えている。   As shown in FIGS. 1A and 1B, the surface light source device 100a includes three LEDs 1 that are point light sources, and a light guide plate 2 on which light emitted from the LEDs 1 is incident. Yes. The LED 1 is disposed in the vicinity of one end surface (hereinafter referred to as a light incident surface 2c) of the light guide plate 2, and is directed from the light incident surface 2c toward the other end surface (hereinafter referred to as a counter light incident surface 2d). Incident light of the LED 1 is emitted in a planar shape from a light exit surface 2a substantially orthogonal to the light incident surface 2c and the counter light incident surface 2d. In addition, the surface light source device 100a is disposed on the light exit surface 2a in the vicinity of the light entrance surface 2c of the light exit surface 2a, on the light exit surface 2a, and on the light exit surface 2a. And a diffusion plate 4 that diffuses the light from the light evenly. Further, the surface light source device 100 a is disposed on the diffusion plate 4, collects the light that has passed through the diffusion plate 4 and changes its direction, and is disposed on the vertical prism sheet 5 and passes through the vertical prism sheet 5. And a horizontal prism sheet 6 that collects and changes the direction of the collected light.

縦プリズムシート５は、ＬＥＤ１の並び方向に直行する方向に三角プリズムの溝が形成されており、横プリズムシート６は、ＬＥＤ１の並び方向に三角プリズムの溝が形成されている。   The vertical prism sheet 5 has a triangular prism groove formed in a direction perpendicular to the LED 1 arrangement direction, and the horizontal prism sheet 6 has a triangular prism groove formed in the LED 1 arrangement direction.

反射板３は、拡散反射の特性を有する白色ポリエステルフィルムミラーで構成されており、導光板２外部に取り出された光を反射して導光板２内部に戻す役割を有する。   The reflection plate 3 is composed of a white polyester film mirror having a diffuse reflection characteristic, and has a role of reflecting light extracted outside the light guide plate 2 and returning it to the inside of the light guide plate 2.

導光板２は、屈折率が１．４９のポリメチルメタクリレート（ＰＭＭＡ）で形成されている。この導光板２の反出光面２ｂには、スクリーン印刷によってシボと呼ばれる半球凹状の反射ドット（図示せず）が形成されており、この反射ドットにより光が散乱されて出光面２ａから光が取り出され、拡散板４、縦プリズムシート５および横プリズムシート６を透過して、最適な配光角度で光が放射される。なお、反射ドットは、半球凸状でもよい。また、ここでは導光板２としてＰＭＭＡを用いているが、材料はこれに限らず、アクリル樹脂、ポリカーボネート樹脂（ＰＣ）、シクロオレフィン系材料などの高屈折率の透明樹脂を用いることができる。   The light guide plate 2 is made of polymethyl methacrylate (PMMA) having a refractive index of 1.49. On the light exit surface 2b of the light guide plate 2, hemispherical concave reflection dots (not shown) are formed by screen printing, and light is scattered by the reflection dots and light is extracted from the light exit surface 2a. Then, the light is transmitted through the diffusion plate 4, the vertical prism sheet 5 and the horizontal prism sheet 6, and light is emitted at an optimal light distribution angle. The reflective dots may be hemispherical convex. Here, although PMMA is used as the light guide plate 2, the material is not limited to this, and a transparent resin having a high refractive index such as an acrylic resin, a polycarbonate resin (PC), or a cycloolefin-based material can be used.

導光板２の入光面２ｃ近傍の領域（以下、導入部２１と称する）には、図２に示すように、光拡散面２２ａが設けられている。光拡散面２２ａは、出光面２ａに垂直な方向に形成され、かつ入光面２ｃを臨む凹面である２つの円弧面が、ＬＥＤ１の中心位置で連結する形状である。光拡散面２２ａの各円弧面はそれぞれ半円弧状であり、その直径は各ＬＥＤ１間の距離の３分の１に形成されている。   As shown in FIG. 2, a light diffusing surface 22 a is provided in a region in the vicinity of the light incident surface 2 c of the light guide plate 2 (hereinafter referred to as the introduction portion 21). The light diffusing surface 22a is formed in a direction perpendicular to the light exit surface 2a and has a shape in which two arcuate surfaces that are concave surfaces facing the light incident surface 2c are connected at the center position of the LED 1. Each arc surface of the light diffusing surface 22a has a semicircular arc shape, and its diameter is formed to one third of the distance between the LEDs 1.

光拡散面２２ａは、出光面２ａおよび反出光面２ｂから所定の深さを有してそれぞれ設けられた溝３０の側面である。この溝３０は、所定の幅を有する２つの円弧溝がＬＥＤ１の中心位置で連結するように構成されており、円弧溝が連結する部分での溝幅ｗｃ、即ちＡＡ線で示す方向における溝幅ｗｃがその他の部分の同方向における溝幅ｗよりも大きく形成されている。そして、２つの円弧溝の連結位置および各円弧溝の端部は鋭角に形成されている。また、ここでは出光面２ａ側に設けられた溝３０の深さと反出光面２ｂ側に設けられた溝３０の深さとを同一としているが、これは同一でなくてもよい。
なお、導光板２を入光面２ｃから反入光面２ｄの方向に見たとき、導入部２１の幅Ｈは入光面２ｃから溝３０の外端までの距離である。そして、この導入部２１の深さは導光板２の出光面２ａから反出光面２ｂまで、即ち導光板の厚さＴである。 The light diffusion surface 22a is a side surface of the groove 30 provided with a predetermined depth from the light exit surface 2a and the counter light exit surface 2b. The groove 30 is configured such that two arc grooves having a predetermined width are connected at the center position of the LED 1, and the groove width wc at the portion where the arc grooves are connected, that is, the groove width in the direction indicated by the AA line. wc is formed to be larger than the groove width w in the same direction of other portions. The connecting position of the two arc grooves and the end of each arc groove are formed at an acute angle. Here, the depth of the groove 30 provided on the light exit surface 2a side is the same as the depth of the groove 30 provided on the anti-light exit surface 2b side, but this need not be the same.
When the light guide plate 2 is viewed in the direction from the light incident surface 2 c to the opposite light incident surface 2 d, the width H of the introduction portion 21 is a distance from the light incident surface 2 c to the outer end of the groove 30. The depth of the introduction portion 21 is the thickness T of the light guide plate from the light exit surface 2a to the light exit surface 2b of the light guide plate 2.

実施の形態１の面光源装置１００ａの寸法は、各ＬＥＤ１間の距離Ｌが２０.０ｍｍ、入光面２ｃから溝３０の外端までの距離、即ち導入部２１の幅Ｈが３．９７ｍｍ、溝３０の幅ｗが０．５ｍｍ、溝３０の円弧溝が連結する部分の幅ｗｃが３．３ｍｍ、導光板の厚さＴが２．０ｍｍ、溝３０の深さｄが０．５ｍｍである。ここで、面光源装置１００ａの導入部２１の幅Ｈに対する各ＬＥＤ１間の距離Ｌの比率は５．０である。   The dimensions of the surface light source device 100a of the first embodiment are such that the distance L between the LEDs 1 is 20.0 mm, the distance from the light incident surface 2c to the outer end of the groove 30, that is, the width H of the introducing portion 21 is 3.97 mm, The width w of the groove 30 is 0.5 mm, the width wc of the portion where the arc grooves of the groove 30 are connected is 3.3 mm, the thickness T of the light guide plate is 2.0 mm, and the depth d of the groove 30 is 0.5 mm. . Here, the ratio of the distance L between the respective LEDs 1 to the width H of the introduction part 21 of the surface light source device 100a is 5.0.

次に、図３および４を用いて実施の形態１の面光源装置１００ａの動作を説明する。
図３および４において、矢印はＬＥＤ１より放射された光の軌跡を示している。なお、ＬＥＤ１の発光面に対し垂直方向を放射角度０°と定義する。 Next, the operation of the surface light source device 100a according to the first embodiment will be described with reference to FIGS.
3 and 4, arrows indicate the locus of light emitted from the LED 1. A direction perpendicular to the light emitting surface of the LED 1 is defined as a radiation angle of 0 °.

ＬＥＤ１から放射された光は、図３に示すように、入光面２ｃから導光板２の内部に入射する。そして、放射角度０°から６０°近くまでの光が光拡散面２２ａで全反射する。全反射した光は光拡散面２２ａの円弧面に沿ってさらに全反射を繰り返し、光拡散面２２ａの端部付近で入光面２ｃから導光板２の外部に取り出される。   The light emitted from the LED 1 is incident on the inside of the light guide plate 2 from the light incident surface 2c as shown in FIG. And the light from radiation angle 0 degree to near 60 degrees is totally reflected by the light-diffusion surface 22a. The totally reflected light further repeats total reflection along the arc surface of the light diffusion surface 22a, and is taken out of the light guide plate 2 from the light incident surface 2c near the end of the light diffusion surface 22a.

導光板２の外部に取り出された光は反射板３によって反射され、再び入光面２ｃから導光板２内部に入射する。これにより、光拡散面２２ａの端部付近が疑似的に新たな光源となる。この結果、ＬＥＤ１から放射された光は、入光面２ｃと平行な方向に拡散され輝度ムラが抑制される。また、反射板３は拡散反射の特性を有するため、反射板３に反射された光はあらゆる放射角度を持って入光面２ｃから入射する。このためＬＥＤ１の指向性を十分に低減できる。また、光拡散面２２ａの各円弧面の直径を各点ＬＥＤ１間の距離の３分の１としたので、各ＬＥＤ１間に上記の新たな光源を等間隔で形成することができる。   The light extracted to the outside of the light guide plate 2 is reflected by the reflection plate 3 and enters the light guide plate 2 from the light incident surface 2c again. As a result, the vicinity of the end of the light diffusion surface 22a becomes a pseudo-new light source. As a result, the light emitted from the LED 1 is diffused in a direction parallel to the light incident surface 2c, and luminance unevenness is suppressed. Further, since the reflecting plate 3 has a diffuse reflection characteristic, the light reflected by the reflecting plate 3 is incident from the light incident surface 2c with any radiation angle. For this reason, the directivity of LED1 can fully be reduced. Moreover, since the diameter of each circular arc surface of the light diffusion surface 22a is set to one third of the distance between the respective points LED1, the above-mentioned new light sources can be formed at equal intervals between the respective LEDs 1.

一方、光拡散面２２ａに当たらない光は、図４に示すように、ＬＥＤ１からの放射光分布を保ったまま導光板２の中央部分を反入光面２ｄに向かって伝搬していく。このとき、溝３０の底面３０ａに照射された光は全反射するので、溝３０の円弧溝が連結する部分での溝幅ｗｃを調整することによって、反出光面２ｂに当たる光の量を変化させることができる。即ち、溝３０の光拡散面２２ａは光を拡散させる機能を持ち、溝３０の底面３０ａは、反出光面２ｂに当てる光の分布を調整するための遮光体としての機能を持つ。   On the other hand, as shown in FIG. 4, the light not hitting the light diffusing surface 22a propagates through the central portion of the light guide plate 2 toward the anti-light-incident surface 2d while maintaining the distribution of radiated light from the LED 1. At this time, since the light applied to the bottom surface 30a of the groove 30 is totally reflected, adjusting the groove width wc at the portion where the circular arc groove of the groove 30 is connected changes the amount of light hitting the light-reflecting light surface 2b. be able to. That is, the light diffusing surface 22a of the groove 30 has a function of diffusing light, and the bottom surface 30a of the groove 30 has a function as a light blocking body for adjusting the distribution of light applied to the light exiting surface 2b.

ここで、比較例の面光源装置として、実施の形態１の面光源装置１００ａと反出光面２ｂ側の溝３０の溝幅のみが異なるものを示す。比較例の面光源装置は、図５に示すように、円弧溝が連結する部分の溝幅ｗｃとその他の部分の溝幅ｗとが同一である。この場合、図６に示すように、反出光面２ｂ側の溝３０の円弧溝が連結する部分での溝幅ｗｃが実施の形態１の面光源装置１００ａよりも狭いので、反出光面２ｂに照射される光の量は面光源装置１００ａよりも増加する。   Here, as the surface light source device of the comparative example, one in which only the groove width of the groove 30 on the side of the light exit surface 2b is different from the surface light source device 100a of the first embodiment. In the surface light source device of the comparative example, as shown in FIG. 5, the groove width wc of the portion where the arc grooves are connected and the groove width w of the other portion are the same. In this case, as shown in FIG. 6, the groove width wc at the portion where the arc groove of the groove 30 on the side of the light exit surface 2b is connected is narrower than that of the surface light source device 100a of the first embodiment. The amount of light to be irradiated is larger than that of the surface light source device 100a.

次に、シミュレーションを実施したときの、実施の形態１に係る面光源装置１００ａおよび比較例の面光源装置における導光板２内部の相対輝度分布について説明する。図７において、横軸は導光板２における２つのＬＥＤ１間の中央からの位置を示し、縦軸は相対輝度を示す。図７（ａ）は、実施の形態１の面光源装置１００ａにおいて図４に示す入光面２ｃから５ｍｍの地点であるＣＣ線に沿った断面の反出光面２ｂから反射された光の相対輝度分布を示している。また、図７（ｂ）は、比較例の面光源装置において図６に示す入光面２ｃから５ｍｍの地点であるＦＦ線に沿った断面の反出光面２ｂから反射された光の相対輝度分布を示している。   Next, the relative luminance distribution inside the light guide plate 2 in the surface light source device 100a according to Embodiment 1 and the surface light source device of the comparative example when the simulation is performed will be described. In FIG. 7, the horizontal axis indicates the position from the center between the two LEDs 1 in the light guide plate 2, and the vertical axis indicates the relative luminance. FIG. 7A shows the relative luminance of light reflected from the light exit surface 2b in the cross section along the CC line, which is a point 5 mm from the light incident surface 2c shown in FIG. 4 in the surface light source device 100a of the first embodiment. Distribution is shown. FIG. 7B shows the relative luminance distribution of light reflected from the light exit surface 2b in the cross section along the FF line, which is a point 5 mm from the light incident surface 2c shown in FIG. 6 in the surface light source device of the comparative example. Is shown.

図７（ａ）において、入光面２ｃから５ｍｍの位置における反出光面２ｂから反射される光、即ち出光面２ａから取り出される光は、各ＬＥＤ１間にも広がっていることがわかる。例えば、２つのＬＥＤ１間の中央である０ｍｍ付近での相対輝度は約０．２５であり、ＬＥＤ１の正面である１０ｍｍ付近での相対輝度は０．６５である。   In FIG. 7A, it can be seen that the light reflected from the light exit surface 2b at a position 5 mm from the light incident surface 2c, that is, the light extracted from the light exit surface 2a spreads between the LEDs 1 as well. For example, the relative luminance near 0 mm that is the center between the two LEDs 1 is about 0.25, and the relative luminance near 10 mm that is the front of the LED 1 is 0.65.

一方、図７（ｂ）において、入光面２ｃから５ｍｍの位置における反出光面２ｂから反射される光、即ち出光面２ａから取り出される光は、図７（ａ）ほど各ＬＥＤ１間に広がっていないことがわかる。例えば、０ｍｍ付近の相対輝度は約０．２１であり、１０ｍｍ付近での相対輝度は０．７５である。   On the other hand, in FIG. 7B, the light reflected from the light exit surface 2b at a position 5 mm from the light incident surface 2c, that is, the light extracted from the light exit surface 2a spreads between the LEDs 1 as shown in FIG. I understand that there is no. For example, the relative luminance near 0 mm is about 0.21, and the relative luminance near 10 mm is 0.75.

従来、出光面２ａから出射される光の相対輝度を調整するために、反出光面２ｂに形成する反射ドットの密度やドット半径を反出光面２ｂの場所によって変える手法が用いられている。本発明者らの実験によれば、導光板２の出光面２ａから取り出される光の分布において、２つのＬＥＤ１間の中央での相対輝度と、各ＬＥＤの正面での相対輝度との比が３以下であれば、上記の反射ドットの密度やドット半径を場所により変える必要はなく、拡散板４、縦プリズムシート５および横プリズムシート６の構成で輝度ムラを解消させることができることを確認している。したがって、比較例の面光源装置においては、反射ドットの密度やドット半径を場所により変えなければ輝度ムラを抑制することができず、実施の形態１の面光源装置１００ａであれば、反射ドットの密度やドット半径を場所により変えなくても輝度ムラを抑制することができる。このように、溝３０の円弧溝が連結する部分の溝幅ｗｃを調整することで、反射ドットの密度やドット半径を場所により変えて相対輝度の調整を行わなくても、輝度ムラを十分に抑制できる。   Conventionally, in order to adjust the relative luminance of the light emitted from the light exit surface 2a, a method of changing the density and dot radius of the reflective dots formed on the light exit surface 2b depending on the location of the light exit surface 2b has been used. According to the experiments by the present inventors, in the distribution of light extracted from the light exit surface 2a of the light guide plate 2, the ratio between the relative luminance at the center between the two LEDs 1 and the relative luminance at the front of each LED is 3. If it is below, it is not necessary to change the density and dot radius of the reflective dots depending on the location, and confirm that the luminance unevenness can be eliminated by the configuration of the diffusion plate 4, the vertical prism sheet 5, and the horizontal prism sheet 6. Yes. Therefore, in the surface light source device of the comparative example, luminance unevenness cannot be suppressed unless the density and dot radius of the reflective dots are changed depending on the location. With the surface light source device 100a of the first embodiment, the reflective dot Luminance unevenness can be suppressed without changing the density or dot radius depending on the location. In this way, by adjusting the groove width wc of the portion where the circular arc grooves of the groove 30 are connected, the luminance unevenness can be sufficiently eliminated without changing the relative luminance by changing the density and dot radius of the reflective dots depending on the location. Can be suppressed.

実施の形態１の面光源装置１００ａによれば、導光板２内の入光面２ｃ近傍に、出光面２ａに垂直な方向に形成され、かつ入光面２ｃ臨む凹面である２つの円弧面が、ＬＥＤ１の中心位置で連結した形状の光拡散面２２ａを設けたので、ＬＥＤ１から入射した光は拡散され輝度ムラが少なくなる。   According to the surface light source device 100a of the first embodiment, two arcuate surfaces that are formed in the direction perpendicular to the light exit surface 2a in the vicinity of the light entrance surface 2c in the light guide plate 2 and are concave surfaces facing the light entrance surface 2c are formed. Since the light diffusing surface 22a having the shape connected at the center position of the LED 1 is provided, the light incident from the LED 1 is diffused and luminance unevenness is reduced.

また、入光面２ｃが平面という簡素な形状である導光板２を用いて輝度ムラを低減することができる。   In addition, it is possible to reduce luminance unevenness by using the light guide plate 2 having a simple shape in which the light incident surface 2c is a flat surface.

また、反射板３を備えるとともに、光拡散面２２ａの各円弧面をそれぞれ半円弧状に形成したので、入光面２ｃから入射した光は、反射板３へ向かって全反射され、反射板３によって反射され再び入光面２ｃから導光板２内部に入射される。この結果、ＬＥＤ１から放出された光を入光面２ｃと平行な方向に拡散することができる。   Further, since the reflecting plate 3 is provided and each arc surface of the light diffusing surface 22a is formed in a semicircular shape, the light incident from the light incident surface 2c is totally reflected toward the reflecting plate 3, and the reflecting plate 3 Is again incident on the inside of the light guide plate 2 from the light incident surface 2c. As a result, the light emitted from the LED 1 can be diffused in a direction parallel to the light incident surface 2c.

また、出光面２ａおよび反出光面２ｂから所定の深さを有してそれぞれ設けられた溝３０の側面に光拡散面２２ａを形成したので、溝３０の円弧溝が連結する部分での溝幅ｗｃを調整することによって、反出光面２ｂに当たる光の量を変化させ、輝度ムラを抑制することができる。   Further, since the light diffusion surface 22a is formed on the side surface of the groove 30 provided with a predetermined depth from the light exit surface 2a and the counter light exit surface 2b, the groove width at the portion where the arc grooves of the groove 30 are connected. By adjusting wc, it is possible to change the amount of light striking the light exit surface 2b and to suppress luminance unevenness.

なお、実施の形態１では、光拡散面２２ａの各円弧面の直径は各ＬＥＤ１間の距離の３分の１としたが、これに限らず、例えば各ＬＥＤ１間の距離の４分の１としてもよい。光拡散面２２ａの直径を小さくすることにより、導入部２１の幅Ｈを小さくすることができる。また、ＬＥＤ１の数は３個としたが、これに限定されない。   In the first embodiment, the diameter of each arc surface of the light diffusing surface 22a is set to one third of the distance between the LEDs 1. However, the present invention is not limited to this. Also good. By reducing the diameter of the light diffusion surface 22a, the width H of the introduction part 21 can be reduced. Moreover, although the number of LED1 was three, it is not limited to this.

実施の形態２．
図８および図９は、実施の形態２に係る面光源装置を示すものであって、図８は導光板の光拡散面を拡大して示す上面図、図９は図８のＤＤ線に沿って示す断面図である。
実施の形態２の面光源装置は、図８に示すように、導光板２に複数の光拡散面を備えている点では実施の形態１と同様であるが、実施の形態１では隣り合う光拡散面２２ａは互いに離れて形成されているのに対し、実施の形態２の光拡散面２２ｂは、隣り合う光拡散面の端部同士を連結し切れ目なく繋げるようにして構成されている。そして、光拡散面２２ｂは、図９に示すように、入光面２ｃから遠ざかるように深さ方向へ傾斜している。この傾斜角度は、１０°以下が望ましい。また、光拡散面２２ｂの各円弧の直径は、実施の形態１と同様に各ＬＥＤ１間の距離の３分の１に形成されている。なお、その他の構成は実施の形態１と同様であるので説明を省略する。 Embodiment 2. FIG.
8 and 9 show the surface light source device according to Embodiment 2, in which FIG. 8 is an enlarged top view showing the light diffusion surface of the light guide plate, and FIG. 9 is taken along the line DD in FIG. FIG.
The surface light source device of the second embodiment is the same as the first embodiment in that the light guide plate 2 includes a plurality of light diffusion surfaces as shown in FIG. The diffusion surfaces 22a are formed apart from each other, whereas the light diffusion surface 22b of the second embodiment is configured to connect the end portions of adjacent light diffusion surfaces and connect them without breaks. And as shown in FIG. 9, the light-diffusion surface 22b inclines in the depth direction so that it may distance from the light-incidence surface 2c. This inclination angle is desirably 10 ° or less. Further, the diameter of each arc of the light diffusion surface 22b is formed to be one third of the distance between the LEDs 1 as in the first embodiment. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

次に実施の形態２の面光源装置の動作を説明する。
ＬＥＤ１から出射された光は、図３に示す実施の形態１と同様に、入光面２ｃから導光板２の内部に入射し、光拡散面２２ｂの円弧に沿って全反射され、入光面２ｃから導光板２の外部に取り出される。そして、導光板２の外部に取り出された光は、反射板３によって反射され、再び入光面２ｃから導光板２の内部に入射し、再び光拡散面２２ｂの円弧に沿って全反射され拡散される。即ち、光は光拡散面２２ｂの円弧面を渡り次いで強く拡散されていく。 Next, the operation of the surface light source device of the second embodiment will be described.
The light emitted from the LED 1 enters the light guide plate 2 from the light incident surface 2c and is totally reflected along the arc of the light diffusion surface 22b, as in the first embodiment shown in FIG. 2c is taken out of the light guide plate 2. Then, the light extracted to the outside of the light guide plate 2 is reflected by the reflection plate 3 and again enters the light guide plate 2 from the light incident surface 2c, and is totally reflected and diffused again along the arc of the light diffusion surface 22b. Is done. In other words, light crosses the arc surface of the light diffusing surface 22b and is then strongly diffused.

また、図９に示すように光拡散面２２ｂに傾斜を設けているので、入光面２ｃから入射した光は導光板２の中央部に向かって反射される。これにより、図９の矢印に示すような出光面２ａとほぼ水平に放射されて光拡散面２２ｂに入射する光に対しても、導光板２の中央部に導くことができる。   Further, as shown in FIG. 9, since the light diffusion surface 22 b is inclined, the light incident from the light incident surface 2 c is reflected toward the central portion of the light guide plate 2. As a result, the light that is radiated almost horizontally with the light exit surface 2 a as shown by the arrow in FIG. 9 and enters the light diffusion surface 22 b can be guided to the center of the light guide plate 2.

実施の形態２によれば、複数の光拡散面を備え、隣り合う光拡散面の端部同士を連結するようにして光拡散面２２ｂを構成したので、実施の形態１の効果に加えて、より強く光が拡散され、輝度ムラをさらに抑制することができる。   According to the second embodiment, since the light diffusing surface 22b is configured to include a plurality of light diffusing surfaces and to connect ends of adjacent light diffusing surfaces, in addition to the effects of the first embodiment, Light is more strongly diffused and luminance unevenness can be further suppressed.

また、光拡散面２２ｂを入光面２ｃから遠ざかるように深さ方向へ傾斜するようにしたので、導光板２の中央に向かって光を導き、反入光面２ｄに向かって光を伝搬させやすくすることができる。   Further, since the light diffusion surface 22b is inclined in the depth direction so as to be away from the light incident surface 2c, the light is guided toward the center of the light guide plate 2 and propagated toward the anti-light incident surface 2d. It can be made easier.

実施の形態３．
図１０ないし図１２は、実施の形態３に係る面光源装置を示すものであって、図１０は導光板の出光面側の光拡散面を拡大して示す上面図、図１１は導光板の反出光面側の光拡散面を拡大して示す上面図、図１２は図１０および図１１のＥＥ線に沿って示す断面図である。 Embodiment 3 FIG.
10 to 12 show a surface light source device according to Embodiment 3, in which FIG. 10 is an enlarged top view showing a light diffusion surface on the light exit surface side of the light guide plate, and FIG. FIG. 12 is a cross-sectional view taken along the line EE in FIGS. 10 and 11 and FIG. 12 is an enlarged top view showing the light diffusion surface on the light exit surface side.

実施の形態３の面光源装置は、図１０および図１２に示すように、導光板２の導入部２１において出光面２ａ側に突出する突出部２０が設けられており、この突出部２０に実施の形態２で説明した光拡散面２２ｂが形成されている。また、反出光面２ｂ側には、図１１および図１２に示すように、反出光面２ｂから所定の深さを有して設けられた溝３０の側面に実施の形態２で説明した光拡散面２２ｂが形成されている。また、反出光面２ｂ側に設けられた溝３０の外端は平坦状に形成されている。その他の構成および動作は実施の形態２と同様であるのでその説明を省略する。   As shown in FIGS. 10 and 12, the surface light source device of the third embodiment is provided with a protrusion 20 that protrudes toward the light exit surface 2 a in the introduction portion 21 of the light guide plate 2. The light diffusion surface 22b described in the second embodiment is formed. Further, as shown in FIGS. 11 and 12, the light diffusion described in the second embodiment is provided on the side of the groove 30 provided at a predetermined depth from the reflection light surface 2b on the reflection light surface 2b side. A surface 22b is formed. Further, the outer end of the groove 30 provided on the light exit surface 2b side is formed flat. Since other configurations and operations are the same as those of the second embodiment, the description thereof is omitted.

実施の形態３によれば、導光板２の導入部２１において出光面２ａ側に突出する突出部２０を設け、この突出部２０に光拡散面２２ｂを形成したので、実施の形態２と同様の効果が得られると共に、突出部２０の高さの分だけ導光板２の厚さを薄くすることができる。   According to the third embodiment, the projecting portion 20 that projects to the light exit surface 2a side is provided in the introduction portion 21 of the light guide plate 2, and the light diffusion surface 22b is formed on the projecting portion 20, so that the same as in the second embodiment. The effect is obtained, and the thickness of the light guide plate 2 can be reduced by the height of the protrusion 20.

なお、反射板３を突出部２０の光拡散面２２ｂに沿って折り曲げ、出光面２ａに重ねるようにしてもよい。このようにすることで、光拡散面２２ｂで全反射せずに導光板２の外部に取り出された光が出光面２ａから再び導光板２の内部に入射して輝度ムラが発生してしまうことを防止することができる。   The reflector 3 may be bent along the light diffusing surface 22b of the protruding portion 20 and overlapped with the light exit surface 2a. By doing so, light extracted outside the light guide plate 2 without being totally reflected by the light diffusing surface 22b is incident on the inside of the light guide plate 2 again from the light exit surface 2a, resulting in luminance unevenness. Can be prevented.

実施の形態４．
図１３は、実施の形態４に係る面光源装置の導光板の光拡散面を拡大して示す上面図である。
実施の形態１では、半円弧状の円弧面２つをＬＥＤ１の中心で連結させるようにして構成した光拡散面２２ａを示したが、図１３に示すように、円弧の中心角θが９０°である円弧面２つをＬＥＤ１の中心で連結させるようにして光拡散面２２ｄを構成してもよい。その他の構成は実施の形態１と同様であるので説明を省略する。 Embodiment 4 FIG.
FIG. 13 is an enlarged top view showing the light diffusion surface of the light guide plate of the surface light source device according to Embodiment 4.
In the first embodiment, the light diffusion surface 22a configured to connect two semicircular arc surfaces at the center of the LED 1 is shown. However, as shown in FIG. 13, the arc center angle θ is 90 °. The light diffusing surface 22d may be configured so that two circular arc surfaces are connected at the center of the LED 1. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

次に実施の形態４の面光源装置の動作を説明する。
図１３において、矢印はＬＥＤ１から放射される光の軌跡を示しており、放射角度が大、中および小の３通りの光の軌跡Ｌ、ＭおよびＳを示している。入光面２ｃから導光板２内部に入射した光のうち放射角度が中および小の光は、光拡散面２２ｄで全反射されて導光板２内の方向へ伝搬していく。一方、導光板２の内部に入射した光のうち放射角度が大の光は、光拡散面２２ｄで全反射された後、入光面２ｃでさらに全反射され、導光板２内の方向へ伝搬していく。これらにより、ＬＥＤ１から放射された光は入光面２ｃと平行な方向に拡散される。 Next, the operation of the surface light source device of Embodiment 4 will be described.
In FIG. 13, arrows indicate the trajectories of light emitted from the LED 1, and indicate three types of light trajectories L, M, and S with large, medium, and small radiation angles. Of the light incident on the light guide plate 2 from the light incident surface 2c, the light having a medium and small radiation angle is totally reflected by the light diffusion surface 22d and propagates in the direction of the light guide plate 2. On the other hand, light having a large radiation angle out of the light incident on the inside of the light guide plate 2 is totally reflected by the light diffusion surface 22d and then further totally reflected by the light incident surface 2c and propagates in the direction within the light guide plate 2. I will do it. As a result, the light emitted from the LED 1 is diffused in a direction parallel to the light incident surface 2c.

実施の形態４によれば、中心角θが９０°である円弧面２つをＬＥＤの中心で連結させるようにして光拡散面１００ｄを構成したので、入光面２ｃから導光板２に入射した光は、入光面２ｃの方向に全反射され、さらに入光面２ｃで導光板内２の方向に向かって全反射される。この結果、ＬＥＤ１から放射された光は入光面２ｃと平行な方向に拡散されるので、輝度ムラを低減することができる。   According to the fourth embodiment, since the light diffusing surface 100d is configured by connecting two arc surfaces having a central angle θ of 90 ° at the center of the LED, the light is incident on the light guide plate 2 from the light incident surface 2c. The light is totally reflected in the direction of the light incident surface 2c, and further totally reflected in the direction of the light guide plate 2 by the light incident surface 2c. As a result, the light emitted from the LED 1 is diffused in a direction parallel to the light incident surface 2c, so that the luminance unevenness can be reduced.

また、入光面２ｃが平面という簡素な形状である導光板２を用いて輝度ムラ低減することができる。   Further, the luminance unevenness can be reduced by using the light guide plate 2 having a simple shape in which the light incident surface 2c is a flat surface.

なお、光拡散面２２ｄの円弧面の中心角θは９０°に限らず、１２０°までであれば上記と同様の作用効果を得ることができる。   Note that the center angle θ of the arc surface of the light diffusion surface 22d is not limited to 90 °, and if it is up to 120 °, the same effect as described above can be obtained.

実施の形態５．
図１４は、実施の形態５に係る面光源装置の導光板の光拡散面を拡大して示す上面図である。
実施の形態５の面光源装置は、入光面２ｃに反射面２５ａが設けられていること以外は実施の形態４と同様である。この反射面２５ａは、出光面２ａに垂直な方向に形成され、光拡散面２２ｄから遠ざかるように反入光面２ｄの方向へ直線状に傾斜している。また、反射面２５ａは、入光面２ｃに設けられた断面が三角形の切り欠き２６の側面である。その他の構成は実施の形態４と同様であるのでその説明を省略する。このように構成することで、光拡散面２２ｄで全反射され、出光面２ｃで全反射された光が、さらに反射面２５ａで全反射されるので、実施の形態４の効果に加えて、より強く前方へ光を曲げる効果が得られる。また、反射面２５ａは直線状に傾斜しているという簡素な形状であるので、導光板２の入光面２ｃを複雑な形状にすることなく輝度ムラを低減することができる。 Embodiment 5 FIG.
FIG. 14 is an enlarged top view showing the light diffusion surface of the light guide plate of the surface light source device according to Embodiment 5.
The surface light source device of the fifth embodiment is the same as that of the fourth embodiment except that the light incident surface 2c is provided with the reflecting surface 25a. The reflection surface 25a is formed in a direction perpendicular to the light exit surface 2a, and is linearly inclined in the direction of the light incident surface 2d so as to be away from the light diffusion surface 22d. The reflecting surface 25a is a side surface of the notch 26 having a triangular cross section provided on the light incident surface 2c. Since other configurations are the same as those of the fourth embodiment, description thereof is omitted. With this configuration, the light that is totally reflected by the light diffusion surface 22d and totally reflected by the light exit surface 2c is further totally reflected by the reflection surface 25a. In addition to the effects of the fourth embodiment, more The effect of bending light strongly forward is obtained. Further, since the reflecting surface 25a has a simple shape that is inclined linearly, luminance unevenness can be reduced without making the light incident surface 2c of the light guide plate 2 complicated.

実施の形態６．
図１５は、実施の形態６に係る面光源装置の導光板の光拡散面を拡大して示す上面図である。
実施の形態５では、光拡散面２２ｄから遠ざかるように反入光面２ｄの方向へ直線状に傾斜した反射面２５ａを示したが、図１５に示すように、光拡散面２２ｄから遠ざかるように反入光面２ｄの方向へ曲面状に傾斜した反射面２５ｂとしてもよい。このように構成することで、光は反射面２５ｂの曲面に沿って全反射するので、実施の形態５の効果に加えて、さらに強く前方へ光を曲げる効果が得られる。また、反射面２５ｂは曲面という簡素な形状であるので、導光板２の入光面２ｃを複雑な形状にすることなく輝度ムラを低減することができる。 Embodiment 6 FIG.
FIG. 15 is an enlarged top view showing the light diffusing surface of the light guide plate of the surface light source device according to Embodiment 6.
In the fifth embodiment, the reflection surface 25a that is linearly inclined in the direction of the anti-light-incident surface 2d is shown so as to be away from the light diffusion surface 22d. However, as shown in FIG. 15, the reflection surface 25a is away from the light diffusion surface 22d. The reflection surface 25b may be inclined in a curved shape toward the anti-light-incident surface 2d. With this configuration, the light is totally reflected along the curved surface of the reflecting surface 25b, so that in addition to the effect of the fifth embodiment, the effect of bending the light more strongly forward can be obtained. Further, since the reflecting surface 25b has a simple shape such as a curved surface, luminance unevenness can be reduced without making the light incident surface 2c of the light guide plate 2 complicated.

実施の形態７．
図１６は実施の形態７に係る面光源装置の導光板の光拡散面を拡大して示す上面図である。
実施の形態７の面光源装置の光拡散面２２ｇは、図１６に示すように、図１３に示す実施の形態４の光拡散面２２ｄの隣り合う光拡散面の端部同士を直線状に連結して切れ目なく繋げるようにして構成されている。また、この光拡散面２２ｇは入光面２ｃから遠ざかるように深さ方向へ傾斜して設けられている。この傾斜角度は１０°以下であることが望ましい。なお、その他の構成は実施の形態４と同様であるので説明を省略する。 Embodiment 7 FIG.
FIG. 16 is an enlarged top view showing the light diffusing surface of the light guide plate of the surface light source device according to Embodiment 7.
As shown in FIG. 16, the light diffusing surface 22g of the surface light source device of the seventh embodiment linearly connects the ends of adjacent light diffusing surfaces of the light diffusing surface 22d of the fourth embodiment shown in FIG. And it is configured to connect seamlessly. Further, the light diffusion surface 22g is provided to be inclined in the depth direction so as to be away from the light incident surface 2c. This inclination angle is preferably 10 ° or less. Since other configurations are the same as those in the fourth embodiment, description thereof is omitted.

実施の形態７によれば、隣り合う光拡散面の端部同士を直線状に連結して切れ目なく繋げるようにして光拡散面２２ｇを構成したので、入光面２ｃから入射した光は、光拡散面２２ｇと入光面２ｃとの間で全反射を繰り返す。これにより、実施の形態４の効果に加えて、より強く光が拡散され、さらに輝度ムラを抑制することができる。   According to the seventh embodiment, the light diffusion surface 22g is configured such that the ends of the adjacent light diffusion surfaces are connected in a straight line so as to be connected seamlessly. Total reflection is repeated between the diffusion surface 22g and the light incident surface 2c. Thereby, in addition to the effects of the fourth embodiment, the light is diffused more strongly and the luminance unevenness can be further suppressed.

また、光拡散面２２ｇを入光面２ｃから遠ざかるように深さ方向へ傾斜するようにしたので、光拡散面２２ｇ導光板２の中央に向かって光を導き、反入光面２ｄに向かって光を伝搬させやすくすることができる。   Further, since the light diffusing surface 22g is inclined in the depth direction so as to move away from the light incident surface 2c, the light is guided toward the center of the light diffusing surface 22g light guide plate 2 and toward the anti-light incident surface 2d. Light can be easily propagated.

実施の形態８．
実施の形態８の面光源装置は、出光面２ａ側の光拡散面を図１３の実施の形態４に示した光拡散面２２ｄとし、反出光面２ｂ側の光拡散面を図１６の実施の形態７に示した光拡散面２２ｇとしたものである。光拡散面２２ｄは光が反入光面２２ｄに向かって比較的伝搬し易い構造であり、光拡散面２２ｇは溝３０の上面３０ａにより反出光面２ｂに当たる光の量の調整をし易い構造である。このように構成することで、光の利用効率が良く且つ輝度ムラを抑制することができる。 Embodiment 8 FIG.
In the surface light source device of the eighth embodiment, the light diffusion surface on the light exit surface 2a side is the light diffusion surface 22d shown in the fourth embodiment in FIG. 13, and the light diffusion surface on the anti-light exit surface 2b side is the embodiment in FIG. The light diffusing surface 22g shown in the seventh embodiment is used. The light diffusing surface 22d has a structure in which light is relatively easily propagated toward the anti-incident light surface 22d, and the light diffusing surface 22g has a structure in which the amount of light that strikes the anti-light emitting surface 2b is easily adjusted by the upper surface 30a of the groove 30. is there. With such a configuration, it is possible to improve the light use efficiency and suppress luminance unevenness.

実施の形態９．
図１７は実施の形態９に係る液晶表示装置を示す斜視図である。
実施の形態９の液晶表示装置２００は、図１７に示すように、図１に示す実施の形態１の面光源装置１００ａと、面光源装置１００ａの横プリズムシート６に対向させて配置された液晶パネル１５０とを備えている。 Embodiment 9 FIG.
FIG. 17 is a perspective view showing a liquid crystal display device according to the ninth embodiment.
As shown in FIG. 17, the liquid crystal display device 200 according to the ninth embodiment is a liquid crystal disposed so as to face the surface light source device 100a according to the first embodiment shown in FIG. 1 and the horizontal prism sheet 6 of the surface light source device 100a. And a panel 150.

実施の形態９によれば、実施の形態１に係る面光源装置１００ａを用いたので、輝度ムラの少ない液晶表示装置を得ることができる。   According to the ninth embodiment, since the surface light source device 100a according to the first embodiment is used, a liquid crystal display device with little luminance unevenness can be obtained.

なお、ここでは実施の形態１の面光源装置１００ａを備えた液晶表示装置２００を示したが、これに代えて上記各実施の形態のいずれの面光源装置を用いても同様の作用効果を得ることができる。   In addition, although the liquid crystal display device 200 provided with the surface light source device 100a of Embodiment 1 is shown here, the same effect can be obtained by using any surface light source device of each of the above embodiments instead. be able to.

また、上記各実施の形態は互いに組み合わせることができる。   The above embodiments can be combined with each other.

１ ＬＥＤ
２ 導光板
２ａ 出光面
２ｂ 反出光面
２ｃ 入光面
２ｄ 反入光面
３ 反射板
２０ 突出部
２１ 導入部
２２ａ、２２ｂ、２２ｄ、２２ｇ 光拡散面
２５ａ、２５ｂ 反射面
２６ 切り欠き
３０ 溝
１００ａ 面光源装置
１５０ 液晶パネル
２００ 液晶表示装置 1 LED
2 Light guide plate 2a Light exit surface 2b Light exit surface 2c Light entrance surface 2d Light entrance surface 3 Reflector 20 Protruding portion 21 Introducing portion 22a, 22b, 22d, 22g Light diffusion surface 25a, 25b Reflective surface 26 Notch 30 Groove 100a surface Light source device 150 Liquid crystal panel 200 Liquid crystal display device

Claims (10)

点光源と、前記点光源から出射された光が入射される導光板とを備え、
前記点光源は、前記導光板の一方の端面に近接して配置され、
前記導光板は、前記一方の端面から入射した前記光を、前記一方の端面および前記一方の端面に対向する他方の端面に対し略直交する出光面から面状に出射させるようにした面光源装置において、
前記導光板内の前記一方の端面近傍に光拡散面が設けられ、
前記光拡散面は、前記出光面に垂直な方向に形成され、かつ前記一方の端面に臨む凹面である２つの円弧面が、前記点光源の中心位置で連結して構成されていることを特徴とする面光源装置。 A point light source, and a light guide plate on which light emitted from the point light source is incident,
The point light source is disposed close to one end face of the light guide plate,
The light guide plate emits the light incident from the one end face in a planar shape from a light exit surface substantially orthogonal to the one end face and the other end face facing the one end face. In
A light diffusion surface is provided in the vicinity of the one end surface in the light guide plate,
The light diffusing surface is formed in a direction perpendicular to the light exit surface, and two arcuate surfaces which are concave surfaces facing the one end surface are connected at the center position of the point light source. A surface light source device. 光拡散面は、一方の端面から導光板に入射した光を、前記一方の端面の方向に全反射し、前記一方の端面で前記導光板内の方向に全反射する形状であることを特徴とする請求項１に記載の面光源装置。   The light diffusing surface has a shape in which light incident on the light guide plate from one end surface is totally reflected in the direction of the one end surface, and is totally reflected in the direction in the light guide plate at the one end surface. The surface light source device according to claim 1. 一方の端面を覆って配置される反射板を備え、
光拡散面は、前記一方の端面から入射した光を前記反射板へ向かって反射する形状であることを特徴とする請求項１に記載の面光源装置。 Including a reflector arranged to cover one end surface;
The surface light source device according to claim 1, wherein the light diffusion surface has a shape that reflects light incident from the one end surface toward the reflection plate. 光拡散面は、出光面およびこの出光面と対向する反出光面から所定の深さを有してそれぞれ設けられていることを特徴とする請求項１ないし３のいずれか一項に面光源装置。   4. The surface light source device according to claim 1, wherein the light diffusing surface is provided with a predetermined depth from the light exit surface and the counter light exit surface facing the light exit surface. . 複数の光拡散面を備え、隣り合う前記光拡散面の端部同士が連結されていることを特徴とする請求項４に記載の面光源装置。   The surface light source device according to claim 4, comprising a plurality of light diffusing surfaces, wherein ends of the adjacent light diffusing surfaces are connected to each other. 光拡散面は、一方の端面から遠ざかるように深さ方向へ傾斜していることを特徴とする請求項５に記載の面光源装置。   6. The surface light source device according to claim 5, wherein the light diffusing surface is inclined in the depth direction so as to be away from the one end surface. 導光板の一方の端面近傍には出光面側へ突出する突出部が設けられ、前記突出部に光拡散面が設けられていることを特徴とする請求項５または６に記載の面光源装置。   The surface light source device according to claim 5, wherein a protrusion that protrudes toward the light exit surface is provided in the vicinity of one end surface of the light guide plate, and a light diffusion surface is provided at the protrusion. 導光板の一方の端面に、光拡散面で反射された光を他方の端面の方向へ反射する反射面が設けられ、
前記反射面は、出光面に垂直な方向に形成され、前記光拡散面から遠ざかるように他方の端面の方向へ傾斜していることを特徴とする請求項２に記載の面光源装置。 On one end surface of the light guide plate, a reflection surface that reflects light reflected by the light diffusion surface in the direction of the other end surface is provided,
The surface light source device according to claim 2, wherein the reflection surface is formed in a direction perpendicular to the light exit surface, and is inclined toward the other end surface so as to be away from the light diffusion surface. 前記反射面は、曲面で形成されていることを特徴とする請求項８に記載の面光源装置。   The surface light source device according to claim 8, wherein the reflection surface is a curved surface. 請求項１ないし９のいずれか一項に記載の面光源装置を液晶パネルの背面側に備えた液晶表示装置。   A liquid crystal display device comprising the surface light source device according to claim 1 on the back side of a liquid crystal panel.
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KR20160124466A (en) * 2015-04-20 2016-10-28 주식회사 엘엠에스 Light Guiding Plate including Light Diffusion Parts and Back Light Unit Having the Same
KR101721943B1 (en) * 2015-04-20 2017-04-03 주식회사 엘엠에스 Light Guiding Plate including Light Diffusion Parts and Back Light Unit Having the Same

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