Title:
FOCUSING SCREEN AND METHOD OF PRODUCING SAME
Document Type and Number:
Japanese Patent JPS5331127
Kind Code:
A
Abstract:
An optically-generated or computer-generated holographic diffusing screen usable in bringing an image to focus thereon is a hologram which upon reconstruction displays a substantially transparent annulus on a substantially opaque background. The annulus preferably has an outer diameter substantially equal to the exit pupil of the image-forming lens, which image is to be focused. The radial width of the transparent annular portion is very small relative to the outer diameter of the annulus. The holographic diffusion screen may be formed by making a holographic image of the substantially annular pattern or by exposing a holographic plate with two collimated mutually coherent beams of light, one beam being perpendicular to the plate while the other is at an angle with respect to the first beam, rotating the holographic recording plate a predetermined amount, and repeating the exposing and rotating steps until a predetermined number of exposures has been completed.
Inventors:
ISAIA GURASAAAINBARI
Application Number:
JP8970277A
Publication Date:
March 24, 1978
Filing Date:
July 26, 1977
Export Citation:
Assignee:
YEDA RES & DEV
International Classes:
G03B13/24; G02B5/02; G02B5/32; G03H1/28; (IPC1-7): G03B13/24