发明授权
US5459532A Automatic focus adjuster for projection display systems having focus adjustment display symbols 失效
具有焦点调节显示符号的投影显示系统的自动对焦调节器

Automatic focus adjuster for projection display systems having focus
adjustment display symbols
摘要:
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.
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