发明名称 |
LENS WITH GRATING ELEMENT, AND IMAGE PICKUP DEVICE AND READER USING IT |
摘要 |
PURPOSE: A lens having a grating element is provided to prevent degradation of diffraction efficiency by specifying an m-th pitch of a rising/ falling shape, counting from the center of the lens. CONSTITUTION: When the focal length of a grating element is fg and center wavelength at the time of forming the grating element is lambda 0 it is so constituted that an m-th pitch Pm of a rising/falling shape, counting from the lens center satisfies an expression. In this case, it is desirable that a grating element face in a lens with the grating element is of kinoform and that the lens is formed of either glass or resin. It is further desirable that the lens with the grating element is formed of infrared absorbing material. As a result, the grating element face is easily formed, and degradation of diffraction efficiency is prevented so as to suppress such an influence that unnecessary scattered light is projected on an image face to degrade image focusing performance.
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申请公布号 |
KR20010034934(A) |
申请公布日期 |
2001.04.25 |
申请号 |
KR20010002863 |
申请日期 |
2001.01.18 |
申请人 |
MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. |
发明人 |
BOKU KAZUTAKE;ONO SHUSUKE;SASANO TOMOHIKO;TANAKA YASUHIRO;YAMAGATA MICHIHIRO |
分类号 |
G02B27/00;G02B5/18;(IPC1-7):G02B27/00 |
主分类号 |
G02B27/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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