05434632 is referenced by 10 patents and cites 13 patents.

An image projection device comprising at least one display panel (26, 27, 28), a projection lens system (C) and a focus-error detection system is described. The focus-error detection system comprises an auxiliary radiation source (50) delivering a focus measuring beam (b), an auxiliary lens (61) for capturing radiation (b.sub.r) diffusely reflected by a projection screen (D), and a detection unit (60) for measuring the size of a spot (S) formed on the screen by the beam (b).

Title
Image projection apparatus with a autofocusing system
Application Number
8/204976
Publication Number
5434632
Application Date
March 2, 1994
Publication Date
July 18, 1995
Inventor
A Carmichael
Eindhoven
NL
Agent
Michael J Balconi Lamica
Assignee
U S Philips Corporation
NY, US
IPC
G03B 3/00
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