Browse Prior Art Database

BIGON SCANNER

IP.com Disclosure Number: IPCOM000025161D
Original Publication Date: 1983-Dec-31
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 95K

Publishing Venue

Xerox Disclosure Journal

Abstract

The most common method of scanning a laser beam is with a multifaceted polygon. A multifaceted polygon must be diamond turned in order to get the Dlacement accuracy required from the beam reflected off each facet. Additionally, these systems require an optical system that is insensitive to the remaining pvramidal error of the polygon. A single spinning mirror would eliminate the facet to facet alignment problem but the efficiency (light delivered to target) would decrease dramatically and the motor speed required for the same throughput would increase correspondingly. A two facet scanning device (bigon) represents a compromise solution to this problem. The use of a wide angle lens achieves a scanning efficiency of 50% and a simple alignment procedure eliminates the need for pyramidal error correction.

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(EROX DISCLOSURE JOURNAL

BIGON SCANNER Louis D. Mailloux Charles H. Russell

Proposed Classification
U.S. Cl. 178/7.6

Int. Cl. H041 15/00

I

FIG. I

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Volume 8 Number 6 November/December 1983 467

[This page contains 1 picture or other non-text object]

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BIGON SCANNER (Cont'd)

The most common method of scanning a laser beam is with a multifaceted polygon. A multifaceted polygon must be diamond turned in order to get the Dlacement accuracy required from the beam reflected off each facet. Additionally, these systems require an optical system that is insensitive to the remaining pvramidal error of the polygon. A single spinning mirror would eliminate the facet to facet alignment problem but the efficiency (light delivered to target) would decrease dramatically and the motor speed required for the same throughput would increase correspondingly. A two facet scanning device (bigon) represents a compromise solution to this problem. The use of a wide angle lens achieves a scanning efficiency of 50% and a simple alignment procedure eliminates the need for pyramidal error correction.

The bigon is a small right angle prism with a reflective coating on the two 90 degree surfaces. The prism is mounted on the end of a motor shaft with the hypotenuse down as seen in Figures 1 and 2. A slot is cut in the motor shaft below the prism and is used to align the laser beam reflected off of the two facets.

The alignment is done with the special clamp shown in Figure 3. A laser beam is reflected off of each facet of the bigon as the motor is spun. The degree of misalignment between the two facets can be seen by the separation of th...