公开(公告)号：US20180217351A1

公开(公告)日：2018-08-02

申请号：US15525777

申请日：2014-11-14

申请人： Hitachi Maxell, Ltd.

发明人： Akihiro SHIRAISHI ,  Kazuo SHIKITA ,  Satoshi NAKAYAMA

IPC分类号： G02B7/08 ,  G03B21/14 ,  G03B3/12 ,  G02B7/02

CPC分类号： G02B7/08 ,  G02B7/021 ,  G02B27/149 ,  G02B27/36 ,  G03B3/10 ,  G03B3/12 ,  G03B21/142

摘要： A projection type image display device includes a focus adjusting unit that adjusts a focal position of a projection lens. The projection lens includes a front side lens group and a rear side lens group which are displaceable toward the screen. The focus adjusting unit includes a back focus adjusting unit that adjusts a position of the rear side lens group and a peripheral adjusting unit that adjusts a position of the front side lens group, and the back focus adjusting unit and the peripheral adjusting unit independently adjust the position of the rear side lens group and the position of the front side lens group by individual driving of motors.