发明授权
US6076736A Holographic laser scanning system employing light focusing optics below the holographic scanning disc 失效
全息激光扫描系统在全息扫描盘下采用光聚焦光学

Holographic laser scanning system employing light focusing optics below
the holographic scanning disc
摘要:
A holographic laser scanning system for scanning bar code symbols and the like, comprising: a holographic scanning disc; a plurality of laser beam sources; a plurality of beam folding mirrors adjacent the holographic scanning disc; a plurality of light focusing elements disposed beneath the holographic scanning disc; and plurality of photodetectors disposed above the holographic scanning disc. The light focusisng elements below the holographic scanning disc focus reflected laser light collected through the elements of the holographic scanning disc and retransmit the same therethrough off Bragg for direct detection by the photodetectors which are proximately dispposed to and above the holographic scanning disc. Several important advantages are obtained by providing light collection optics disposed below the holographic scanning disc, and retransmitting focused/collected laser light through the holographic scanning disc at an angle substantially off a Bragg angle of about 44 degrees. In particular, it is now possible to design and construct holographic laser scanners employing miultiple laser scanning stations within compact scanner housings having minimized height dimensions, while avoiding interference among the multiple outgoing, incoming and retransmitted laser beams generated within the scanner housing during laser scanning and light collection operations.
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