JP2780046B2 - Backlight device - Google Patents
Backlight deviceInfo
- Publication number
- JP2780046B2 JP2780046B2 JP1144381A JP14438189A JP2780046B2 JP 2780046 B2 JP2780046 B2 JP 2780046B2 JP 1144381 A JP1144381 A JP 1144381A JP 14438189 A JP14438189 A JP 14438189A JP 2780046 B2 JP2780046 B2 JP 2780046B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- transparent substrate
- light source
- backlight device
- lamp housing
- 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.)
- Expired - Lifetime
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
- G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
- G02B6/0031—Reflecting element, sheet or layer
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
- G02B6/0055—Reflecting element, sheet or layer
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/0058—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide
- G02B6/0061—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide to provide homogeneous light output intensity
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0066—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form characterised by the light source being coupled to the light guide
- G02B6/007—Incandescent lamp or gas discharge lamp
- G02B6/0071—Incandescent lamp or gas discharge lamp with elongated shape, e.g. tube
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Light Guides In General And Applications Therefor (AREA)
- Liquid Crystal (AREA)
- Devices For Indicating Variable Information By Combining Individual Elements (AREA)
Description
【発明の詳細な説明】 「産業上の利用分野」 本発明は、液晶ディスプレイ（LCD）の背面に配設さ
れて、該液晶ディスプレイを照射するバックライト装置
に関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight device disposed on the back of a liquid crystal display (LCD) and illuminating the liquid crystal display.
「従来の技術」 近年、液晶ディスプレイは、薄形，軽量、及び低消費
電力などの優れた特徴を有し、この特徴を充分発揮し得
る平面ディスプレイとして各種製品への利用に多大な期
待が寄せられている。しかしながら、液晶ディスプレイ
は、現在産業用及び民生用として広く使用されているCR
T（Cathode Ray Tube）に比較して画質面で劣ってお
り、この画質を改善するためにバックライト形式の液晶
ディスプレイが開発されるに至っている。[Prior art] In recent years, liquid crystal displays have excellent features such as thinness, light weight, and low power consumption, and there are great expectations for use in various products as flat displays that can sufficiently exhibit these features. Have been. However, liquid crystal displays are now widely used for industrial and consumer applications.
The image quality is inferior to T (Cathode Ray Tube), and a backlight type liquid crystal display has been developed to improve the image quality.
この種のバックライト装置は、薄形でかつ軽量である
ことが望まれ、又画面の全領域において輝度が均一であ
ることが必要条件とされている。バックライト装置にお
いて、輝度の均一性を高める技術としては、既に各種の
提案がされている。例えば、特開昭57−13478号公報記
載のものは、線状光源の上部に乳白色光散乱体を設け、
かつ該乳白色光散乱体の中央部の層厚を厚くし、端部に
至るに従って薄くして、照明むらをなくし、しかも薄型
でかつ小型化を図り得るようにしたものである。更に、
特開昭60−264039号公報記載のものでは、蛇行状の冷陰
極ランプを用い、特開昭61−219980号公報記載のもので
は、紫外線ランプ、及び該紫外線ランプの周辺に配設し
た蛍光体塗布層部を活用し、特開昭62−10621号公報記
載のものでは、導光板中に光源を組み込み、特開昭62−
127717号公報記載のものでは、複数個の光源の上下面に
凹凸レンズを配設し、特開昭63−125975号公報記載のも
のではＵ字型ランプを用い、これによりそれぞれ照射む
らをなくして輝度の均一化を図るようにしてある。更
に、輝度の均一化を図るべく、透明基板内に光散乱体
を、光源側では低濃度で光源より距離を隔たるに従って
高濃度になるように入れた特開昭54−105562号公報記載
のものや、コーティングされた透明基板に光反射手段
を、照明用光源からの距離と照度に反比例する密度分布
で描写する特開昭63−309918号公報記載のバックライト
装置が知られるところである。又、透明基板所謂導光板
中に光源からの放射光を導入する場合に導光板の後面に
凹部を設けて、該凹部内に光源を収納する特開昭55−12
9383号公報記載のものや、導光板の周縁部に溝を設け
て、該溝内に光源を組込む特開昭62−10621号公報記載
のもの、更に導光板の周端部に凹部を設けて、該凹部内
に光源を収納する特開昭62−235905号公報記載のバック
ライト装置も提案されている。This type of backlight device is required to be thin and lightweight, and it is a necessary condition that the luminance is uniform over the entire area of the screen. In the backlight device, various proposals have already been made as a technique for improving the uniformity of luminance. For example, JP-A-57-13478 discloses a milky white light scatterer provided above a linear light source,
In addition, the layer thickness of the central portion of the milky light scatterer is increased, and the thickness is reduced toward the end portion, so that illumination unevenness is eliminated, and furthermore, the thickness and the size can be reduced. Furthermore,
JP-A-60-264039 discloses a meandering cold cathode lamp, and JP-A-61-219980 discloses an ultraviolet lamp and a phosphor disposed around the ultraviolet lamp. Utilizing the coating layer portion, the one described in JP-A-62-10621 incorporates a light source in the light guide plate,
In the method disclosed in Japanese Patent No. 127717, a concave and convex lens is disposed on the upper and lower surfaces of a plurality of light sources, and in the method described in Japanese Patent Application Laid-Open No. 63-125975, a U-shaped lamp is used, thereby eliminating irradiation unevenness. The brightness is made uniform. Further, in order to achieve uniform brightness, a light scatterer is provided in a transparent substrate, and the light source side is provided with a low density and a higher density as the distance from the light source is increased with a higher density as described in JP-A-54-105562. A backlight device described in JP-A-63-309918 is known in which a light reflecting means is depicted on a transparent substrate coated with a light source with a density distribution inversely proportional to the distance from the illumination light source and the illuminance. In the case where radiation light from a light source is introduced into a transparent substrate, a so-called light guide plate, a concave portion is provided on the rear surface of the light guide plate, and the light source is accommodated in the concave portion.
No. 9383, a groove is provided at the peripheral edge of the light guide plate, and that described in Japanese Patent Application Laid-Open No. 62-10621, in which a light source is incorporated in the groove, a concave portion is further provided at the peripheral end of the light guide plate. A backlight device described in JP-A-62-235905, in which a light source is accommodated in the recess, has also been proposed.
「発明が解決しようとする課題」 しかしながら、上記従来のものは、下記の如き問題が
ある。"Problem to be solved by the invention" However, the above-mentioned conventional one has the following problems.
（１） 光散乱体の下面に光源を配設する場合には、バ
ックライト装置全体の厚みが厚くなり嵩張るといった問
題がある。(1) When the light source is provided on the lower surface of the light scatterer, there is a problem that the thickness of the entire backlight device becomes thick and bulky.
（２） 輝度の均一化を図るべく、ランプを複数個設け
る場合には、大面積にすればするほど多数のランプが必
要となってコスト高を招くといった問題がある。(2) When a plurality of lamps are provided in order to make the luminance uniform, there is a problem that as the area is increased, a larger number of lamps is required and the cost is increased.
（３） 蛇行状のランプを用いる場合には、大面積のも
のに適用すると、量産性に欠けるといった問題がある。(3) When a meandering lamp is used, if it is applied to a large-area lamp, there is a problem that mass productivity is lacking.
（４） 透明基板内に光散乱体を入れる場合は、輝度の
均一化を再現性良く製造することが容易でないといった
問題がある。(4) When a light scatterer is placed in a transparent substrate, there is a problem that it is not easy to manufacture a uniform luminance with good reproducibility.
（５） コーィングされた透明基板に光反射手段を描写
する場合は、コーティングしていない透明基板を用いる
ものに比べてコスト高になるといった問題がある。(5) When the light reflecting means is depicted on the coated transparent substrate, there is a problem that the cost is higher than that using a transparent substrate without coating.
（６） 導光板の裏面や端部を加工して光源を収納させ
る場合には、導光板の加工コストが嵩張るといった問題
がある。(6) In the case where the light source is housed by processing the back surface or the end of the light guide plate, there is a problem that the processing cost of the light guide plate is increased.
そこで、本発明は、上記問題点を克服すべくなされた
もので、加工コストが低廉であることはもとより、薄型
かつ軽量で大面積化によっても輝度の均一性を保持し得
て光の利用効率が良好なバックライト装置を提供せんと
するものである。Therefore, the present invention has been made to overcome the above-mentioned problems. In addition to the low processing cost, the present invention is capable of maintaining uniformity of luminance even with a thin, lightweight, and large area, and has a light use efficiency. To provide a favorable backlight device.
「課題を解決するための手段」 本発明は、上記目的を達成すべく、なされたもので、
請求項（１）では、透明基板の四周のうちの少なくとも
１箇所に光源を配設し、かつ該光源としての棒状光源
を、断面が楕円形状でかつ透明基板側が切欠されて開口
するランプハウジング中に、その楕円の２つの焦点の間
に位置させて収納し、かつランプハウジングの開口端の
楕円内面を仮想周面を透明基板の端縁に内接させ、該透
明基板の裏面に光乱反射層を付設したバックライト装置
を特徴とするものである。請求項（２）では、上記光乱
反射層を光源からの距離に応じて高密度化するパターン
で透明基板の裏面に形成し、該透明基板の表面に光拡散
層を付設した請求項（１）記載のバックライト装置を特
徴とするものである。"Means for Solving the Problems" The present invention has been made to achieve the above object.
According to claim (1), a light source is provided at at least one of four circumferences of a transparent substrate, and a rod-shaped light source as the light source is formed in a lamp housing having an elliptical cross section and being opened with a cutout on the transparent substrate side. The lamp is housed between the two focal points of the ellipse, and the inside of the ellipse at the opening end of the lamp housing is inscribed in the virtual peripheral surface to the edge of the transparent substrate. The backlight device is characterized by the following. In claim (2), the light diffusely reflecting layer is formed on the back surface of the transparent substrate in a pattern of increasing the density according to the distance from the light source, and the light diffusion layer is provided on the surface of the transparent substrate. A backlight device according to any one of the preceding claims.
「作用」 本発明は、上記構成において、請求項（１）では、一
つの楕円焦点より放射する光が他方の楕円焦点に集光す
る性質があるが、実際上一つの楕円焦点に一致する線状
光源はなく、ある太さを持つ棒状光源を用いるものであ
るから、該棒状光源を二つの楕円焦点の間に配設して、
棒状光源からの放射光を楕円形状のランプハウジングの
内面に反射させて透明基板の端面に集光させて入光せし
め、更に透明基板の裏面の光乱反射層で乱反射させて、
透明基板の表面から外部に放射させるようにしたもので
ある。請求項（２）では、透明基板の端面から内部に入
射した光が透明基板と空気との界面で光学的密度差によ
り反射を繰返すうちに、光源から隔たるに従って高密度
のパターンで描写された光乱反射層で乱反射し、この乱
反射後に光散乱層で拡散されて外部に放射されて、全面
に亙って輝度むらがなく輝度の均一化を得ることができ
るようにしたものである。[Operation] According to the present invention, in the above structure, in claim (1), light emitted from one elliptical focal point has a property of being condensed on the other elliptical focal point. Since there is no bar-shaped light source and a bar-shaped light source having a certain thickness is used, the bar-shaped light source is disposed between two elliptical focal points,
The emitted light from the rod-shaped light source is reflected on the inner surface of the elliptical lamp housing, condensed on the end surface of the transparent substrate and made incident, and further diffusely reflected on the diffuse reflection layer on the back surface of the transparent substrate.
The light is emitted from the surface of the transparent substrate to the outside. In claim (2), while the light incident from the end face of the transparent substrate into the interior is repeatedly reflected by the optical density difference at the interface between the transparent substrate and air, the light is drawn in a high-density pattern as the distance from the light source increases. The light is irregularly reflected by the light irregular reflection layer, and after the irregular reflection, is diffused by the light scattering layer and radiated to the outside, so that uniform luminance can be obtained without luminance unevenness over the entire surface.
「実施例」 以下に、本発明に係るバックライト装置の実施例を図
面に基づき説明する。第１図及び第２図において、１は
透明基板である。該透明基板１は、光透過率の良好な肉
厚の薄い板で、材質として例えばガラス板、アクリル樹
脂板、ポリカーボネート樹脂板等、無機質若しくは合成
樹脂製の透明板を使用する。透明基板１の４周部のうち
の一側縁に光源２を配設する。上記透明基板１の裏面に
は、光源２からの放射光を乱反射する光乱反射層３を、
光源２からの距離に比例して高密度化するパターンで描
写させてある。光乱反射層３は、反射微粒子としての酸
化チタンを含有する発揮硬化型の、若しくは紫外線硬化
型の白色インクを用い、又は利用する者の希望に応じた
色彩の着色インクを使用する。透明基板１の裏面に光乱
反射層３を形成する方法としては、スクリーン印刷やス
タンプ方式等の公知の技術を用いて描写する。該光乱反
射層３を透明基板１の裏面に形成するに際しては、第３
図に示す如く、単位面積当たりの点の数を同一にし、光
源から距離を隔てるに従って点（ドット）を径大に描写
し、透明基板１の単位面積当たりの光乱反射層３の占有
率を変えるようにしてある。光乱反射層３の点の直径
は、１〜300μ、好ましくは10〜1000μに設定する。一
方、透明基板１の表面には、光拡散層４を添着する。光
拡散層４は、所謂くもりガラス、若しくは表面を粗面化
したプラスチックフィルムが用いられ、コストや耐久性
等から表面を粗面化した光拡散層を有するポリエスルフ
ィルムが好適である。光源２は、一般に広く用いられて
いる蛍光灯の他、細い管径の冷陰極管が、バックライト
装置全体の薄形化及び液晶ディスプレイ（LCD）パネル
に対する温度の影響を押えることができて利用上有利で
ある。該光源２は、断面が濁縁形状のランプハウジング
５内に収納する。楕円形状のランプハウジング５は、一
つの楕円焦点より発生させた光が、他方の楕円焦点に集
光する性質があり、このため、線光源を一方の楕円焦点
に配設し、透明基板の端部を他方の楕円焦点に設置させ
ると、楕円周面上での反射損失と、透明基板の端面への
入光損失を無視すれば、線光源からの光が総で楕円周面
での１回の反射で透明基板に入光させることができ、最
も光の利用効率が高い方法となる。しかしながら、実際
上、理想的な線光源は存在せず、上記の如く一般に用い
られる蛍光灯や冷陰極管のようなある太さを持つ棒状光
源である。従って、光の有効利用という観点から、上記
の如く楕円形状のランプハウジング５の何れかの位置に
配設するかが重要な課題となる。そこで、各種試行実験
と考察の結果、最も光の利用効率の高い手法は、断面が
楕円形状でかつ内面に光鏡面反射層を形成したランプハ
ウジング５内の二つの焦点F1,F2間に棒状の光源２を収
納する。更に、透明基板１の一端面は、ランプハウジン
グ５の開口5aに密嵌し、かつランプハウジング５の楕円
内周面を延長させた仮想の面と内接するように設ける。
透明基板１は5mm程度の厚みがあり、この厚みに相当す
る分だけ楕円内周面よりやや内方に臨むが、この厚み分
で光源から放射されてランプハウジング５の内面に反射
した光を充分に入光させることができる。ランプハウジ
ング５は、上記の如く少なくとも内側の断面が楕円形状
になって金属又はプラスチックより構成され、光源２か
ら発生した光を内面で反射させて透明基板１の端面に導
く機能と、光源からの光の漏洩を防ぐ機能と、光源から
発生する熱を放散させる機能とを有する。このため、ラ
ンプハウジング５は、内面に反射効率の高いアルミ蒸着
処理を施したアルミケースや、反射効率の高い白色塗料
を塗布したアルミケースなどが好適である。ランプハウ
ジング５の楕円形状の大きさは、楕円が大きい程棒状の
光源２の太さと相対的な差が大きくなり、線状光源とし
ての取扱いができて理想的であるが、バックライト装置
の厚さ及び外寸法の制約と光源の太さと透明基板１の厚
みから適当に設定する。又、上記透明基板１の光源２の
光が入光する端面以外に反射テープ６を貼着して、透明
基板１の周縁からの光の漏洩を防ぐことができる。Hereinafter, an embodiment of a backlight device according to the present invention will be described with reference to the drawings. 1 and 2, reference numeral 1 denotes a transparent substrate. The transparent substrate 1 is a thin plate having good light transmittance and a transparent plate made of an inorganic or synthetic resin such as a glass plate, an acrylic resin plate, a polycarbonate resin plate, or the like. The light source 2 is disposed on one side edge of the four peripheral portions of the transparent substrate 1. On the rear surface of the transparent substrate 1, a light diffusely reflecting layer 3 for irregularly reflecting light emitted from the light source 2 is provided.
The pattern is depicted in a pattern that increases in density in proportion to the distance from the light source 2. The light diffuse reflection layer 3 uses a development-curable or ultraviolet-curable white ink containing titanium oxide as reflective fine particles, or a colored ink having a color according to a user's desire. As a method of forming the light diffuse reflection layer 3 on the back surface of the transparent substrate 1, description is made using a known technique such as screen printing or a stamp method. When the light diffuse reflection layer 3 is formed on the back surface of the transparent substrate 1,
As shown in the figure, the number of points per unit area is made the same, and points (dots) are drawn to have a larger diameter as the distance from the light source is increased, and the occupation ratio of the light scattering layer 3 per unit area of the transparent substrate 1 is changed. It is like that. The diameter of the point of the light irregular reflection layer 3 is set to 1 to 300 μ, preferably 10 to 1000 μ. On the other hand, the light diffusion layer 4 is attached to the surface of the transparent substrate 1. The light diffusion layer 4 is made of so-called frosted glass or a plastic film having a roughened surface, and is preferably a polyester film having a light diffusion layer with a roughened surface in terms of cost, durability, and the like. As the light source 2, in addition to a fluorescent lamp generally used widely, a cold-cathode tube having a small diameter can be used because the backlight device can be made thinner and the influence of temperature on a liquid crystal display (LCD) panel can be suppressed. It is more advantageous. The light source 2 is housed in a lamp housing 5 having a muddy cross section. The elliptical lamp housing 5 has a property that light generated from one elliptical focal point is condensed on the other elliptical focal point. Therefore, a linear light source is disposed at one elliptical focal point, and the end of the transparent substrate is disposed. If the part is set at the other elliptical focal point, if the reflection loss on the elliptical peripheral surface and the light incident loss on the end face of the transparent substrate are ignored, the light from the linear light source will collectively reach once on the elliptical peripheral surface. The light can enter the transparent substrate by the reflection of light, and this is a method with the highest light use efficiency. However, in practice, there is no ideal line light source, and a rod-like light source having a certain thickness, such as a fluorescent lamp or a cold-cathode tube, which is generally used as described above. Therefore, from the viewpoint of effective use of light, it is important to determine where to place the lamp housing 5 in the elliptical shape as described above. As a result of various trial experiments and considerations, as a result, the method with the highest light use efficiency is that the cross section between the two focal points F 1 and F 2 in the lamp housing 5 having an elliptical cross-section and having a light-mirror reflective layer formed on the inner surface. The rod-shaped light source 2 is housed. Further, one end surface of the transparent substrate 1 is provided so as to be closely fitted to the opening 5a of the lamp housing 5 and to be inscribed in a virtual surface obtained by extending the elliptical inner peripheral surface of the lamp housing 5.
The transparent substrate 1 has a thickness of about 5 mm, and slightly inward from the inner peripheral surface of the ellipse by an amount corresponding to this thickness, but the light emitted from the light source and reflected on the inner surface of the lamp housing 5 by this thickness is sufficient. Can be incident on the light. The lamp housing 5 is made of metal or plastic with at least an inner cross section having an elliptical shape as described above. The lamp housing 5 reflects light generated from the light source 2 on the inner surface to guide the light to the end surface of the transparent substrate 1, and It has a function of preventing light leakage and a function of dissipating heat generated from the light source. For this reason, it is preferable that the lamp housing 5 be an aluminum case in which an inner surface is subjected to aluminum vapor deposition processing with high reflection efficiency, or an aluminum case in which white paint with high reflection efficiency is applied. The size of the elliptical shape of the lamp housing 5 is ideal because the larger the ellipse, the larger the relative difference with the thickness of the rod-shaped light source 2, and can be handled as a linear light source. The thickness of the light source and the thickness of the transparent substrate 1 are appropriately set based on the restrictions on the size of the light source and the external dimensions. In addition, a reflective tape 6 can be adhered to the transparent substrate 1 at a position other than the end face where the light from the light source 2 enters, thereby preventing light from leaking from the periphery of the transparent substrate 1.
そして、上記構成のバックライト装置は、まず光源２
からの放射光が第２図に矢印で示す如く、ランプハウジ
ング５の内面で反射して透明基板１の端面に集光し、該
透明基板１内に入光する。光源２は上記の如くランプハ
ウジング５内の二つの焦点F1,F2間に位置させて収納さ
せてあるから、光源２の放射光がランプハウジング５の
内面で反射すると、大部分の放射光が透明基板１の端面
に集光して入光する。透明基板１内に入光した放射光
は、透明基板１と空気との界面での光学的密度差により
入光角に依存した反射を繰返しながら進行する。この進
行に伴い、光乱反射層３に達して入光すると、内部に含
有する酸化チタンで乱反射し、この結果乱反射光は透明
基板１の表面と空気との界面に対して臨界角以下になっ
て、該透明基板１の表面から外部に放射する。つまり、
光乱反射層３は、第３図に示す如く透明基板１の単位面
積当たりの占有率が光源２から距離を隔たるに従い増加
させてあるから、光源２からの距離による光の不均一を
防止して、光量の多い光源２の付近から光量の少ない距
離の隔った箇所まで全面に亙って均一な乱反射光量を得
ることできる。光乱反射層３で乱反射した光は、透明基
板１の表面の光拡散層４を通過するが、光拡散層４が微
小な凹凸から成っていることから光が拡散されて外部に
放射され、これにより光乱反射層３と光乱反射層３のパ
ターン以外の領域との間の光量変化所謂「影の発生」を
なくし、均一な輝度が得られるようにする。光源２から
発生した熱は、ハウジング５を通じて外部に放散され
る。Then, the backlight device having the above-described configuration first includes the light source 2
2 is reflected by the inner surface of the lamp housing 5 and condensed on the end face of the transparent substrate 1 as shown by the arrow in FIG. Since the light source 2 is housed between the two focal points F 1 and F 2 in the lamp housing 5 as described above, most of the radiated light is emitted when the emitted light of the light source 2 is reflected on the inner surface of the lamp housing 5. Are condensed and enter the end face of the transparent substrate 1. The radiated light entering the transparent substrate 1 travels while repeating reflection depending on the incident angle due to a difference in optical density at the interface between the transparent substrate 1 and air. With this progress, when the light reaches the light diffuse reflection layer 3 and enters the light, the light is diffused and reflected by the titanium oxide contained therein. As a result, the light is diffused at a critical angle or less with respect to the interface between the surface of the transparent substrate 1 and air. , And radiates from the surface of the transparent substrate 1 to the outside. That is,
As shown in FIG. 3, the light scattered reflection layer 3 increases the occupancy per unit area of the transparent substrate 1 as the distance from the light source 2 increases, so that unevenness of light due to the distance from the light source 2 is prevented. Thus, it is possible to obtain a uniform diffuse reflection light amount over the entire surface from the vicinity of the light source 2 having a large light amount to a place separated by a distance having a small light amount. The light diffusely reflected by the light diffuse reflection layer 3 passes through the light diffusion layer 4 on the surface of the transparent substrate 1. However, since the light diffusion layer 4 is formed of minute irregularities, the light is diffused and emitted to the outside. As a result, a change in the amount of light between the light diffuse reflection layer 3 and the area other than the pattern of the light diffuse reflection layer 3, that is, so-called “shadow generation” is eliminated, and uniform luminance can be obtained. The heat generated from the light source 2 is radiated outside through the housing 5.
尚、本発明において、上記光乱反射層として、上記実
施例の他に、光源からの距離に応じて単位面積当たりの
点の数を変え、又は光源からの距離に応じて点の径と単
位面積当たりの点の数の両者を変えることもでき、又、
点に限らず、線を用いて、その線の太さや線相互間の間
隔を変える形式をも採用できる。更に、上記光乱反射層
３が描写された透明基板１の裏面に、アルミ等金属を蒸
着した光鏡面反射手段を付設して、透明基板１の下方か
ら光が漏洩することを防止し、更に光の利用率を高める
ようにすることもできる。In the present invention, in addition to the above embodiment, the number of points per unit area is changed according to the distance from the light source, or the diameter and the unit area of the point are changed according to the distance from the light source. You can change both the number of points per hit,
Not limited to points, a form in which a line is used to change the thickness of the line and the interval between the lines can also be adopted. Further, on the back surface of the transparent substrate 1 on which the light diffuse reflection layer 3 is depicted, a light mirror reflecting means on which metal such as aluminum is vapor-deposited is provided to prevent light from leaking from below the transparent substrate 1. It is also possible to increase the utilization rate of the information.
又、光源２については、上記実施例では、透明基板１
の一端側にのみ配設したが、対向する両端部側に配設す
る２個用いた形式や、四周縁の総てに配設する形式にす
ることもでき、光源の数を増加させれば、輝度の向上を
図ることができる。この場合も、各光源からの距離に応
じた密度のパターンで光乱反射層を形成することは勿論
であり、光の利用率を高めて輝度の均一性に優れるバッ
クライト装置が達成できる。The light source 2 is the transparent substrate 1 in the above embodiment.
Although it is arranged only on one end side, it is also possible to adopt a form using two arranged on both end sides facing each other or a form arranged on all four peripheral edges, if the number of light sources is increased In addition, the luminance can be improved. Also in this case, it is needless to say that the light diffuse reflection layer is formed with a pattern having a density corresponding to the distance from each light source, and a backlight device having high uniformity of luminance by increasing light utilization can be achieved.
「発明の効果」 上記の如く、本発明に係るバックライト装置によれ
ば、光源を透明基板の厚み方向ではなく周縁側に配設す
ることから、バックライト装置としての全体の厚みが、
光源の径を含む透明基板の厚み、光拡散層、光乱反射層
の重層厚、これをハウジングに組着する際の若干のクリ
アランス、その他必要とするハウジング等の部材の厚み
の合計値で済み、しかも輝度の均一性に優れ、従って従
来の技術では困難であった薄形でかつ軽量であり、更に
大面積化を図っても優れた輝度の均一性を得ることがで
きて、光の利用効率が高いバックライト装置を本発明に
おいて提供し得るものである。以上の如き本発明のバッ
クライト装置は、液晶ディスプレイ（LCD）の背後に設
置することにより、薄形でしかも輝度むらのない見易い
画面を実現し得て、液晶ディスプレイ（LCD）の機能の
向上に多大に貢献でき、その他の各種バックライト装置
としても利用できるものである。"Effects of the Invention" As described above, according to the backlight device of the present invention, since the light source is disposed on the peripheral side instead of the thickness direction of the transparent substrate, the overall thickness of the backlight device is
The total value of the thickness of the transparent substrate including the diameter of the light source, the light diffusion layer, the multilayer thickness of the light diffuse reflection layer, some clearance when assembling this to the housing, and the thickness of other necessary components such as the housing, In addition, it has excellent brightness uniformity, so it is thin and lightweight, which was difficult with the conventional technology, and it is possible to obtain excellent brightness uniformity even if the area is increased, and it is possible to use light efficiently. The present invention can provide a backlight device having a high level of reliability. By installing the backlight device of the present invention behind a liquid crystal display (LCD) as described above, it is possible to realize a thin, easy-to-view screen without uneven brightness, and to improve the function of the liquid crystal display (LCD). It can contribute greatly and can be used as various other backlight devices.
第１図は、本発明に係るバックライト装置の実施例を示
す斜視図、第２図は、第１図のバックライト装置のラン
プハウジングによる光の集光状態を示す要部説明図、第
３図は透明基板の裏面に付した光乱反射層の描写形態を
示す説明図である。 １……透明基板、２……光源 ３……光乱反射層、４……光拡散層 ５……ランプハウジングFIG. 1 is a perspective view showing an embodiment of a backlight device according to the present invention. FIG. 2 is an explanatory view of a main part showing a state of condensing light by a lamp housing of the backlight device in FIG. The figure is an explanatory diagram showing a depiction form of the light diffuse reflection layer attached to the back surface of the transparent substrate. DESCRIPTION OF SYMBOLS 1 ... Transparent board, 2 ... Light source 3 ... Light diffuse reflection layer 4, ... Light diffusion layer 5 ... Lamp housing
Claims (2)
に光源を配設し、かつ該光源としての棒状光源を、断面
が楕円形状でかつ透明基板側が切欠されて開口するラン
プハウジング中に、その楕円の２つの焦点の間に位置さ
せて収納し、かつランプハウジングの開口端の楕円内面
の仮想周面を透明基板の端縁に内接させ、該透明基板の
裏面に光乱反射層を付設したことを特徴とするバックラ
イト装置。A light source is provided at at least one of the four circumferences of a transparent substrate, and a rod-like light source as the light source is provided in a lamp housing having an elliptical cross section and being opened with a cutout on the transparent substrate side. The ellipse is stored between the two focal points, and the virtual peripheral surface of the inner surface of the ellipse at the opening end of the lamp housing is inscribed in the edge of the transparent substrate, and the diffusely reflecting layer is provided on the back surface of the transparent substrate. A backlight device characterized in that:
高密度化するパターンで透明基板の裏面に形成し、該透
明基板の表面に光拡散層を付設したことを特徴とする請
求項（１）記載のバックライト装置。2. The method according to claim 1, wherein the light diffuse reflection layer is formed on the back surface of the transparent substrate in a pattern of increasing the density according to the distance from the light source, and the light diffusion layer is provided on the surface of the transparent substrate. The backlight device according to (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1144381A JP2780046B2 (en) | 1989-06-07 | 1989-06-07 | Backlight device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1144381A JP2780046B2 (en) | 1989-06-07 | 1989-06-07 | Backlight device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH039305A JPH039305A (en) | 1991-01-17 |
| JP2780046B2 true JP2780046B2 (en) | 1998-07-23 |
Family
ID=15360808
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1144381A Expired - Lifetime JP2780046B2 (en) | 1989-06-07 | 1989-06-07 | Backlight device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2780046B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7484873B2 (en) | 2004-08-25 | 2009-02-03 | Seiko Instruments Inc. | Illumination device having elliptical body and display device using the same |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04280225A (en) * | 1991-03-08 | 1992-10-06 | Tosoh Corp | Back light |
| JPH04107237U (en) * | 1991-02-26 | 1992-09-16 | 株式会社ウノン技研 | Surface light source component |
| BE1007433A3 (en) * | 1993-07-30 | 1995-06-13 | Philips Electronics Nv | PLATTE image display apparatus, illumination system RADIATION SOURCE AND SUITABLE FOR APPLICATION IN SUCH A flat picture display device. |
| JP2003344662A (en) * | 2002-05-30 | 2003-12-03 | Teikoku Printing Inks Mfg Co Ltd | Manufacturing method of light guide plate for backlight unit, and ultraviolet curing ink |
-
1989
- 1989-06-07 JP JP1144381A patent/JP2780046B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7484873B2 (en) | 2004-08-25 | 2009-02-03 | Seiko Instruments Inc. | Illumination device having elliptical body and display device using the same |
| CN1740846B (en) * | 2004-08-25 | 2011-06-15 | 精工电子有限公司 | Illuminating equipment and display equipment using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH039305A (en) | 1991-01-17 |
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