发明授权
- 专利标题: Optical assembly and apparatus employing same using an aspherical lens and an aperture stop
- 专利标题(中): 光学组件和使用非球面透镜和孔径光阑的装置
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申请号: US819480申请日: 1992-01-10
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公开(公告)号: US5291008A公开(公告)日: 1994-03-01
- 发明人: William H. Havens , Harry R. McKinley , Charles M. Hammond, Jr. , Joseph J. Morabito , Jeffrey B. Powers
- 申请人: William H. Havens , Harry R. McKinley , Charles M. Hammond, Jr. , Joseph J. Morabito , Jeffrey B. Powers
- 申请人地址: NY Skaneateles Falls
- 专利权人: Welch Allyn, Inc.
- 当前专利权人: Welch Allyn, Inc.
- 当前专利权人地址: NY Skaneateles Falls
- 主分类号: G06K7/10
- IPC分类号: G06K7/10
摘要:
There is disclosed an simplified apparatus that enables optical scanners to achieve minimum field curvature and at the same time provide uniformly distributed light on an image sensor. A single element lens, preferably an aspherical lens made of a plastic material is combined with an aperture stop. The combination is capable of reducing lens aberrations and minimizing image field curvature for an object plane that contains indicia to be scanned or read. A suitably demagnified image of the indicia is focused onto an image sensor such as a CCD array. The spatial light distribution function in the image plane can be equalized by an attenuator, such as a neutral density filter or a slit, suitably configured to compensate for the reduced optical efficiency at large field angles. An aspherical lens containing a dye or a cold mirror can be used for limiting light transmission to a range of wavelengths.