Dual-beam scanning electro-optical device from single-beam light source

• US 5,436,755 A
• Filed: 01/10/1994
• Issued: 07/25/1995
• Est. Priority Date: 01/10/1994
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Guerin, Jean-Michel
• Primary Examiner(s): Sugarman, Scott J.
• Assistant Examiner(s): MACK, RICKY LEVERN
• Application Number:
  US08/179,175
• Time in Patent Office: 561 Days
• Field of Search: 359/494, 359/495, 359/249, 359/250, 359/256, 359/259, 359/276, 359/286, 359/255, 359/257, 359/258, 359/281, 359/284, 359/301, 359/303, 359/304, 359/618, 359/629
• US Class Current: 359/249
• CPC Class Codes: G02B 27/10 Beam splitting or combining systems polarising systems G02B27/28; mixing and splitting light signals using optical waveguides G02B6/28; beam shaping, e.g. changing the cross-sectional area, by dividing or superposing multiple light beams G02B27/0905
• CPC Class Codes: G02B 27/12 operating by refraction only
• CPC Class Codes: G02B 6/105 having optical polarisation effects
• CPC Class Codes: G06K 15/1271 by light beam splitting
• CPC Class Codes: H04N 1/04 Scanning arrangements , i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versaH04N1/387 takes precedence
• CPC Class Codes: H04N 1/1135 for the main-scan only
• CPC Class Codes: H04N 1/1911 Simultaneously or substantially simultaneously scanning picture elements on more than one main scanning line, e.g. scanning in swaths
• CPC Class Codes: H04N 1/40037 the reproducing element being a laser

Abstract

A raster output scanning system is disclosed which utilizes a single light source, an electro-optical device and a beam-splitter to generate two light beams in order to simultaneously scan two adjacent scan lines. Two different trains of pixel information are used to control the intensity of the laser light source and the degree of the polarization of the electro-optical device in order to modulate the two light beams with two separate trains of pixel information without using a modulating device. Each of the two light beams exiting the beam-splitter is modulated in accordance with one of the two trains of pixel information.

Claims

1. A raster output scanner comprising:

a laser light source for emitting a light beam;

polarizing means located in the path of the light beam from said laser light source for receiving the light beam and polarizing the light beam at a first polarization degree, a second polarization degree or a third polarization degree;

a medium;

a beam-splitter located in the path of the polarized light beam from said polarizing means for receiving the polarized light beam and splitting the polarized light beam into two light beams for simultaneously scanning two scan lines on said medium;

scanning means located in the path of the two light beams from said beam-splitter and being so constructed and arranged to scan said two light beams onto said medium;

said beam-splitter and said polarizing means being so constructed and arranged that a polarized light beam will pass through said beam-splitter to one of said scan lines on said medium when said polarization means is at said first polarization degree, a polarized light beam will be split into two portions with one portion passing through said beam-splitter to said one scan line on said medium and the other portion of said polarized light beam being deflected to the other of said scan lines on said medium when said polarization means is at said second polarization degree, and a polarized light beam will be deflected to said other scan line on said medium when said polarization means is at said third polarization degree;

means for providing two different trains of pixel information one for each of said scan lines;

controlling means being electrically connected to said polarizing means and responsive to said two trains of pixel information for setting said polarizing means at either said first polarization degree, said second polarization degree or said third polarization degree in accordance with the two trains of pixel information, whereby the two light beams are modulated to scan said two scan lines.

2. The raster output scanner recited in claim 1, further comprising:

selecting means being electrically connected to said laser light source and responsive to said two trains of pixel information for setting said laser light source at maximum intensity, at half intensity or at zero intensity in accordance with the two trains of pixel information.

3. The raster output scanner recited in claim 2, wherein said light source is at maximum intensity when said polarizing means is at said second polarization degree, and said light source is at half intensity when said polarizing means is at either said first polarization degree or said third polarization degree.

4. The raster output scanner recited in claim 1, wherein the first polarization degree is 0°

, the second polarization degree is 45° and

the third polarization degree is 90°

.