Title:
フレネルレンズ、投射スクリーン、対応する投射デバイス及び投射系
Document Type and Number:
Japanese Patent JP2007504515
Kind Code:
A
Abstract:
The Fresnel lens comprises circular, concentric refractive structures. Each refractive structure is delimited by a first surface making a first angle (alpha ) with the plane of incidence (P) and a second surface making a second angle (beta ) with the normal to the plane. There are two refractive structure zones. The first, close to the center, in which each first surface refracts the light in a direction parallel to the lens axis. The second angle of each second surface is equal to the inlet angle (tau int). In the second zone each first surface is such that the refractive structures refract the light in a direction making an angle (tau out) relative to the lens axis. The second angle of each second surface is equal to the inlet angle. An independent claim is also included for overhead projection equipment.
Inventors:
Schubert, Arno
Benoit, Pascal
Benoit, Pascal
Application Number:
JP2006530441A
Publication Date:
March 01, 2007
Filing Date:
May 17, 2004
Export Citation:
Assignee:
Thomson Licensing
International Classes:
G02B3/08; B29D11/00; G02B3/06; G02B3/10; G02B5/18; G02B27/18; G03B21/10; G03B21/62
Attorney, Agent or Firm:
Tadahiko Ito
Shinsuke Onuki
Tadashige Ito
Shinsuke Onuki
Tadashige Ito
Previous Patent: 複数のカラーセグメントのサブセットを有するカラーホイールが設けられ...
Next Patent: 偏光ビームスプリッターおよび偏光ビームスプリッターを用いる投影シス...
Next Patent: 偏光ビームスプリッターおよび偏光ビームスプリッターを用いる投影シス...