发明授权
- 专利标题: Projection lens apparatus
- 专利标题(中): 投影镜头装置
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申请号: US459242申请日: 1983-01-19
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公开(公告)号: US4548480A公开(公告)日: 1985-10-22
- 发明人: Yoshiharu Yamamoto , Yasuo Nakajima , Yoshitomi Nagaoka
- 申请人: Yoshiharu Yamamoto , Yasuo Nakajima , Yoshitomi Nagaoka
- 申请人地址: JPX Kadoma
- 专利权人: Matsushita Electric Industrial Co., Ltd.
- 当前专利权人: Matsushita Electric Industrial Co., Ltd.
- 当前专利权人地址: JPX Kadoma
- 优先权: JPX57-8113 19820120
- 主分类号: G02B9/12
- IPC分类号: G02B9/12 ; G02B13/16 ; G02B13/18 ; G02B3/04
摘要:
A projection lens apparatus for projecting an image from a CRT onto a remote screen. The lens apparatus is basically a Petzval type for a large aperture ratio and comprises three lenses. The first lens is a plastic lens having at least one aspherical surface and the third lens has a bi-aspherical surface. To reduce the thermal drift of the focal position, the second lens is a glass lens, having relatively largely positive optical power.
公开/授权文献
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