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| United States Patent |
6,423,927
|
|
McCulloch
|
July 23, 2002
|
Laser system
Abstract
A laser system (1) for producing a line beam laser output (4) comprises a
laser source (6), and a lens system (12) for modifying the intensity
profile of the incident laser input, and comprising a plurality of lens
elements (16) arranged at a predetermined lens pitch. An optical filter
(9) is provided between the laser source (6) and the lens system (12), the
filter comprising transmissive portions (42) and opaque portions (44). The
transmissive portions (42) define a repeating pattern (46) with a pitch
corresponding to the lens pitch. The optical filter (9) modifies the input
to the lens system (12) such that the output of the lens system gives rise
to a desired intensity profile at the output of the laser system (1). This
desired profile can have a tapered profile at the top of the hat, which
gives improved performance for laser crystallization. The invention can be
implemented with minimum adaptation of an existing top hat profile laser
system.
| Inventors:
|
McCulloch; David J. (Redhill, GB)
|
| Assignee:
|
Koninklijke Philips Electronics N.V. (Eindhoven, NL)
|
| Appl. No.:
|
643486 |
| Filed:
|
August 22, 2000 |
Foreign Application Priority Data
| Current U.S. Class: |
219/121.66; 219/121.73 |
| Intern'l Class: |
B23K 026/00 |
| Field of Search: |
219/121.61,121.62,121.65,121.66,121.73
|
References Cited
U.S. Patent Documents
| 5756364 | May., 1998 | Tanaka et al. | 437/21.
|
| 5815494 | Sep., 1998 | Yamazaki et al. | 372/25.
|
| 6242292 | Jun., 2001 | Yamazaki et al. | 372/25.
|
| Foreign Patent Documents |
| 11214324 | Aug., 1999 | JP.
| |
Primary Examiner: Heinrich; Samuel M.
Attorney, Agent or Firm: Waxler; Aaron
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