| 摘要 |
<p>The invention relates to an optical scanning apparatus (18) having a scanning head (28), including means (48,56,60) for generating a scanning light beam pattern (40) in a focal plane, and detector means (72) for receiving light reflected from a coded record medium positioned in the vicinity of said focal plane. Data processing means (76) are provided to generate output data representative of the scanned data (140) in response to reflected light received by said detector means (72), and adjusting means (94,82) are arranged to adjust the position of the focal plane relative to said scanning head (28) in dependence on the distance of the scanned data (140) from the head. <IMAGE></p> |
