Automatic focus adjuster for projection display systems having focus adjustment display symbols
First Claim
1. A projection type display system comprising:
- a) optical modulation means for modulating a light in accordance with video data;
b) a projection lens system having a projection lens for projecting the modulated light on a screen;
c) automatic adjustment means for focusing images onto the screen;
d) a range finding unit for finding the distance between said projection lens and said screen with a beam of light, said range finding unit comprising(i) a light emitting element for irradiating said screen with said beam of light, and(ii) a light reception device for receiving light reflected from said screen to output an electrical signal corresponding to the light receiving position of said reflected light;
e) a control means, coupled to said automatic adjustment means and to said range finding unit, for sending a control signal to said automatic adjustment means so that said reflected light may irradiate a desired light receiving position in said light receiving device on the basis of said electrical signal; and
f) a pattern display unit, coupled to said optical modulation means, for displaying on said screen a first fixed pattern during a focal adjustment period, and a second fixed pattern when focal adjustment is completed.
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Abstract
A projection type display system having an optical modulation unit which modulates light from a light source in response to preselected video signal data, a projection lens system for projecting the modulated light onto a display screen, and a focal adjustment device which is configured to alter the focal state of a resulting image which is focused onto the screen. The focal state is adjusted by translating the relative position of one or more lenses in the projection lens system with respect to the screen. The focal adjustment device further incorporates a range finding unit which determines the distance between the projection lens system and the targeted display screen, typically using a beam of invisible light, and an automatic adjustment element which adjusts the focal point of the projection lens system to optimally match the determined distance.
22 Citations
9 Claims
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1. A projection type display system comprising:
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a) optical modulation means for modulating a light in accordance with video data; b) a projection lens system having a projection lens for projecting the modulated light on a screen; c) automatic adjustment means for focusing images onto the screen; d) a range finding unit for finding the distance between said projection lens and said screen with a beam of light, said range finding unit comprising (i) a light emitting element for irradiating said screen with said beam of light, and (ii) a light reception device for receiving light reflected from said screen to output an electrical signal corresponding to the light receiving position of said reflected light; e) a control means, coupled to said automatic adjustment means and to said range finding unit, for sending a control signal to said automatic adjustment means so that said reflected light may irradiate a desired light receiving position in said light receiving device on the basis of said electrical signal; and f) a pattern display unit, coupled to said optical modulation means, for displaying on said screen a first fixed pattern during a focal adjustment period, and a second fixed pattern when focal adjustment is completed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification