JPH0165569U

JPH0165569U -

Info

Publication number: JPH0165569U
Application number: JP1988127052U
Authority: JP
Priority date: 1988-09-30
Filing date: 1988-09-30
Publication date: 1989-04-26
Anticipated expiration: 2003-02-15
Also published as: JPH055749Y2

Description

[Brief explanation of the drawing]

第１図はこの考案の一実施例を示した構成図、
第２図はそのフレネルレンズの仮想レンズ面を示
した断面図、第３図は第２図の仮想レンズを模型
的に分解した状態を示す断面図、第４図はこの考
案の用いられるフレネルレンズの集光特性を説明
した構成図、第５図は３本の投射管を備えた具体
例を示したこの考案の構成図、第６図はこの場合
のスクリーンを示した正面図、第７図ａ，ｂはス
クリーンを２枚構成にしたものと１枚構成にした
ものとの比較図、第８図および第９図はそれぞれ
短焦点および長焦点のフレネルレンズを用いた場
合の構成図、第１０図はスクリーン上の位置と輝
度の関係を表した特性図、第１１図は３本の投射
管を備えた従来のものの構成図、第１２図は第１
１図の構成によるスクリーン上の様子を示した正
面図である。１……投射管、２……投射レンズ、３……フレ
ネルレンズ、４……レンチキユラースクリーン、
１Ｒ……赤発光投射管、１Ｇ……緑発光投射管、
１Ｂ……青発光投射管。 FIG. 1 is a configuration diagram showing an embodiment of this invention.
Fig. 2 is a cross-sectional view showing the virtual lens surface of the Fresnel lens, Fig. 3 is a cross-sectional view schematically showing the virtual lens shown in Fig. 2, and Fig. 4 is a Fresnel lens used in this invention. Fig. 5 is a block diagram of this invention showing a specific example with three projection tubes, Fig. 6 is a front view showing the screen in this case, Fig. 7 Figures a and b are comparative diagrams of two screen configurations and one screen configuration; Figures 8 and 9 are configuration diagrams when using short-focus and long-focus Fresnel lenses, respectively; Figure 10 is a characteristic diagram showing the relationship between the position on the screen and the brightness, Figure 11 is a configuration diagram of a conventional one equipped with three projection tubes, and Figure 12 is a diagram showing the relationship between the position on the screen and the brightness.
FIG. 2 is a front view showing what appears on the screen with the configuration shown in FIG. 1; 1... Projection tube, 2... Projection lens, 3... Fresnel lens, 4... Lenticular screen,
1R...Red light emitting projection tube, 1G...Green light emitting projection tube,
1B...Blue luminous projection tube.

Claims

[Scope of utility model registration request]

In the screen of a rear projection television, which is equipped with a screen that receives projection light projected from a projection tube, and the image projected on the screen is viewed from the side opposite to the projection side by the projection tube, the screen A Fresnel lens and a lenticular screen are arranged sequentially from the projection tube side, and the lens surface of the Fresnel lens is arranged to face the exit side, and the focal length of at least the central part of the Fresnel lens is f ₁ , and A screen for a rear projection television, characterized in that f ₁ < f ₂ where f ₂ is the focal length of the outer portion.