Laser scanning apparatus having a scanning beam and a reference beam

• US 5,247,174 A
• Filed: 04/25/1991
• Issued: 09/21/1993
• Est. Priority Date: 05/07/1990
• Status: Expired due to Fees

• Current Assignee: CREO Company Limited
• Original Assignee: Scitex Corporation Ltd. (Suny Cellular Communication Ltd.)
• Inventors: Berman, Dov
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): ALLEN, STEPHONE B
• Application Number:
  US07/691,228
• Time in Patent Office: 880 Days
• Field of Search: 250/205, 250/235, 250/236, 250/227.11, 250/227.12, 250/227.26, 250/227.28, 250/201.1, 358/293, 358/493, 385/147
• US Class Current: 250/235
• CPC Class Codes: G02B 26/103 having movable or deformable optical fibres, light guides or waveguides as scanning elements light guides per se G02B6/00
• CPC Class Codes: G02B 26/123 Multibeam scanners, e.g. using multiple light sources or beam splitters
• CPC Class Codes: H04N 1/047 Detection, control or error compensation of scanning velocity or position H04N1/0402 and H04N1/17 take precedence
• CPC Class Codes: H04N 1/1008 with sub-scanning by translatory movement of the picture-bearing surface
• CPC Class Codes: H04N 1/1013 with sub-scanning by translatory movement of at least a part of the main-scanning components H04N1/107 takes precedence
• CPC Class Codes: H04N 1/1135 for the main-scan only
• CPC Class Codes: H04N 2201/02441 using screws
• CPC Class Codes: H04N 2201/02443 using adhesive
• CPC Class Codes: H04N 2201/04712 using unbroken arrays of detectors, i.e. detectors mounted on the same substrate
• CPC Class Codes: H04N 2201/04729 in the main-scan direction
• CPC Class Codes: H04N 2201/04731 in the sub-scan direction
• CPC Class Codes: H04N 2201/04734 Detecting at frequent intervals, e.g. once per line for sub-scan control
• CPC Class Codes: H04N 2201/04744 by detecting the scanned beam or a reference beam
• CPC Class Codes: H04N 2201/04765 using a solid-state deflector, e.g. an acousto-optic deflector
• CPC Class Codes: H04N 2201/04772 using a phase-locked loop
• CPC Class Codes: H04N 2201/04789 in the main-scan direction
• CPC Class Codes: H04N 2201/04791 in the sub-scan direction
• CPC Class Codes: H04N 2201/04796 Varying the sub-scan control during the main-scan, e.g. for correcting skew, tilt or bow of a scanning beam
• CPC Class Codes: H04N 2201/04798 Varying the main-scan control during the main-scan, e.g. facet tracking

Abstract

Laser scanning apparatus comprising stationary optical laser source apparatus for producing a scanning beam and a reference beam, beam delivery apparatus for delivering the scanning beam onto a surface to be scanned, beam position detector apparatus for measuring the position of the scanning beam by sensing the position of the reference beam and fiber optic apparatus for delivering the scanning beam and the reference beam from the optical laser source apparatus to the beam delivery apparatus.

Claims

1. Laser scanning apparatus comprising:

a stationary optical laser source for producing a scanning beam and a reference beam;

at least one fiber optic lightguide;

a beam delivery system; and

a beam position detector and corrector system;

wherein said at least one fiber optic lightguide is operative to deliver said scanning beam and said reference beam from said optical laser source to said beam delivery system;

wherein said beam delivery system is operative to deliver said scanning beam to a surface to be scanned and said reference beam to said beam position detector and corrector system; and

wherein said beam position detector and corrector system is operative to measure and correct a position of said scanning beam by sensing a position of said reference beam.

2. Laser scanning apparatus according to claim 1 and also comprising motor means for translation of said beam delivery system with respect to said surface to be scanned.

3. Laser scanning apparatus according to claim 1 and also comprising means for adjusting the intensity of said scanning beam as a function of its relative position along a scanning axis.

4. Laser scanning apparatus according to claim 1 and also comprising means for synchronizing data flow with said position of said scanning beam.

5. Laser scanning apparatus according to claim 1 and wherein said at least one fiber optic lightguide comprises at least one single-mode fiber optic lightguide.

6. Laser scanning apparatus according to claim 5 and wherein said beam position detector and corrector system includes detector means for detecting said position of said reference beam, actuator means attached to exit ends of said at least one fiber optic lightguide and closed loop control means for controlling said actuator means in response to measurements produced by said detector means.

7. Laser scanning apparatus according to claim 6 and wherein said actuator means are piezoelectric actuator means.

8. Laser scanning apparatus according to claim 1 and wherein said beam position detector and corrector system includes detector means for detecting said position of said reference beam, actuator means attached to exit ends of said at least one fiber optic lightguide and closed loop control means for controlling said actuator means in response to measurements produced by said detector means.

9. Laser scanning apparatus according to claim 8 and wherein said actuator means are piezoelectric actuator means.

10. Laser scanning apparatus according to claim 8 and also comprising motor means for translation of said beam delivery system with respect to said surface to be scanned.

11. Laser scanning apparatus according to claim 8 and wherein said closed loop control means also include pre-positioning means for counteracting known initial variations in said beam delivery system.

12. Laser scanning apparatus according to claim 8 and also comprising means for adjusting the intensity of said scanning beam as a function of its relative position along a scanning axis.

13. Laser scanning apparatus according to claim 8 and also comprising means for synchronizing data flow with said position of said scanning beam.

14. Laser scanning apparatus according to claim 8 and wherein said fiber optic lightguide comprises at least one single-mode fiber optic lightguide.

15. Laser scanning apparatus according to claim 8 and wherein said at least one actuator comprises piezoelectric actuator means.

16. Laser scanning apparatus comprising:

a stationary optical laser source for producing a scanning beam;

a fiber optic lightguide;

a beam delivery system; and

a beam position detector and corrector system;

wherein said fiber optic lightguide is operative to deliver said sanning beam from said optical laser source to said beam delivery system, and

wherein said beam position detector and corrector system is operative to measure and correct a position of said scanning beam.