3620613 is referenced by 1 patents and cites 4 patents.

An image projected onto the projection screen by a projector is automatically focused by utilizing a photoconductive element which receives the light reflected from the projected screen. The photoconductive element is provided with a boundary to be in alignment with the boundary of the image of the screen to be projected with the projection image. The displacement of the boundary of the image of the screen out of the light received by the element, which automatically controls the focusing system of the projector by means of a servomotor or the like.

Title
Automatic focusing device for projectors
Application Number
04/809,342
Publication Number
3620613
Application Date
March 21, 1969
Publication Date
November 16, 1971
Inventor
Hiromitsu Watanabe
Agent
Sughrue Rothwell Mion Zinn & Macpeak
Assignee
Fuji Photo Film Co
IPC
G03b 03/00
G03B 21/53
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