Invention Grant
- Patent Title: Image display apparatus
- Patent Title (中): 图像显示装置
-
Application No.: US12330997Application Date: 2008-12-09
-
Publication No.: US08169704B2Publication Date: 2012-05-01
- Inventor: Kenichi Saito
- Applicant: Kenichi Saito
- Applicant Address: JP Tokyo
- Assignee: Canon Kabushiki Kaisha
- Current Assignee: Canon Kabushiki Kaisha
- Current Assignee Address: JP Tokyo
- Agency: Canon U.S.A., Inc. IP Division
- Priority: JP2007-319250 20071211
- Main IPC: G02B5/18
- IPC: G02B5/18

Abstract:
The image display apparatus includes an image-forming element, an optical system guiding light from the image-forming element to an exit pupil, and a diffractive optical element disposed between the image-forming element and the optical system or between the optical system and the exit pupil. The diffractive optical element includes plural diffraction grating portions formed of mutually different materials. Each of the diffraction grating portions includes plural grating rings each having a grating surface and a grating side surface. In each of the grating rings, the grating side surface is inclined oppositely to the grating surface with respect to a normal to an enveloping surface passing through apexes of the plural grating rings. The diffractive optical element satisfies the following conditions at least when k=kE: θd(j, k)=sin−1 [{ni·sinθi (j, k)−m(j, k)·λ/P(j, k)}/nd]≦θi(j, k), M(k)=Σ{m(j, k)}=const, and θd(j, k)≦θ≦θi (j, k).
Public/Granted literature
- US20090147362A1 IMAGE DISPLAY APPARATUS Public/Granted day:2009-06-11
Information query