Title:
METHOD AND APPARATUS FOR CONTROLLING THE FOCUS OF A READ/WRITE HEAD FOR AN OPTICAL SCANNER
Document Type and Number:
WIPO Patent Application WO1999063387
Kind Code:
A9
Abstract:
A controller for a scanning head images light from the scanning head onto a target surface for reading and writing data. Light returned from the target surface is received by the same aperture. Light may be conducted from the aperture, for example, by a light waveguide leading to a detector. The focus control of the imaging optics is controlled responsively to the light returned through the aperture. When this returned light is at a maximum, the focusing optics are in focus. A focus controller may be programmed to dither (intentionally vary) the configuration of the optics to determine the focus optimization direction (gradient). In an embodiment with multiple apertures, each employed to scan a respective area of the target surface (in parallel), the light from adjacent apertures is effectively rejected each other aperture thereby eliminating crosstalk.
Inventors:
PHILLIPS EDWARD A
WYETH NEWELL C
WYETH NEWELL C
Application Number:
PCT/US1999/012185
Publication Date:
March 09, 2000
Filing Date:
June 02, 1999
Export Citation:
Assignee:
SCIENCE APPLIC INT CORP (US)
International Classes:
G02B7/04; G02B7/28; G02B26/10; H04N1/028; H04N1/04; (IPC1-7): G02B26/10; G02B7/04; G02B7/28; H04N1/192
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