公开(公告)号：EP0541800A4

公开(公告)日：1993-06-02

申请号：EP91910166

申请日：1991-05-31

申请人： SEIKO EPSON CORPORATION

发明人： BABA, HIROYUKI

IPC分类号： G02B7/09 ,  G02B7/32 ,  G03B3/00 ,  G03B21/00 ,  G03B21/53 ,  G03B27/34 ,  G09F19/18 ,  H04N9/28

CPC分类号： G09F19/18 ,  G02B7/32 ,  G03B21/53 ,  G03B27/34

摘要： A projection type display device has means for modulating light depending upon image information, a projection lens system for projecting the modulated light onto the screen, and a focusing mechanism for adjusting the projection lens system to vary the focusing condition of the image on the screen. The focusing mechanism has a member for measuring the distance between the projection lens and the screen using invisible light, and an automatic adjusting member for bringing the focal point of the projection lens system to a desired position.