EP0153002A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Apparatus for controlling light distribution in line scan optical imaging systems
Assignee: Unisys Corp
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Filing: 1985-01-09
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Granted: —
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Expires: 2005-01-09
Abstract
Abstract Disclosed is a linear strip mask for controllling image plane light level distribution in line scan optical imaging systems. The mask is fabricated photographically on a strip of emulsion coated mylar. The photographic image which is recorded on the mylar strip is a pattern of alternating black and clear sections, the pattern of black sections chosen to modify the non-uniform light pattern output by the system's illumination source to obtain uniform image plane illumination. Also disclosed is a line scan optical imaging system utilizing strip masks to compensate for the non-uniform light output along the length of two fluorescent tubes which illuminate the document scan line and the cos4 drop-off of the imaging system's lens. Light reflected off the document scan line is transmitted via a four bounce folded mirror system and is received by the lens system. Behind the lens system is positioned a multielement photoelectric sensor for converting light reflected from each unit area of the document line being scanned into electrical signals.
Inventors
- 👤 Cobern Eugene Mcgraw
- 👤 Robert Gazzero
- 👤 David Eugene Christian
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 10:29
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/024; H04N1/028; H04N1/02815; H04N1/02845; H04N1/0287; G; G02; G02B; G02B5/00; G02B5/005; G02B5/20; G02B5/205; H04N1/02885; H04N1/03; H04N1/0301; H04N1/0303
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
54 words
A line scan optical imaging system including means for illuminating a line of a printed document and means for converting light reflected from the line of print to electrical signals, wherein the improvement comprises: mask means, positioned between said illuminating means and said document, for controlling light level distribution across said line of print.
Claim 2
Dependent Claim
54 words
A line scan optical imaging system including means for illuminating a line of a printed document and means for converting light reflected from the line of print to electrical signals, wherein the improvement comprises: mask means, positioned between said illuminating means and said document, for controlling light level distribution across said line of print.
Claim 3
Dependent Claim
30 words
The imaging system in accordance with claim 1 wherein said mask means is a linear strip mask, said linear strip mask fabricated from an emulsion coated clear strip of material.
Claim 4
Dependent Claim
31 words
The imaging system in accordance with claim 2 wherein said emulsion is photographically processed to record a pattern of alternating black and clear sections along the length of the clear strip.
Claim 5
Dependent Claim
52 words
The imaging system in accordance with claim 3 wherein said pattern is chosen to block portions of the light from said illuminating means from reaching the line of print, whereby the line of print is illuminated with a selected distribution which is dependent on the pattern of alternating black and clear sections.
Claim 6
Dependent Claim
37 words
The imaging system in accordance with claim 1 wherein said illuminating means includes a fluorescent tube light source, said mask means for partially blocking light from said fluorescent tube from reaching said line of said printed document.
Claim 7
Dependent Claim
58 words
The imaging system in accordance with claim 5 wherein said mask means includes a clear strip of material positioned parallel with the longitudinal axis of said fluorescent tube, sections of said strip coated with an opaque coating to form a pattern which partially blocks light emanating from the fluorescent tube from reaching the line of said printed document.
Claim 8
Dependent Claim
66 words
The imaging system in accordance with claim 6 wherein said pattern includes a plurality of opaque spaced apart lines perpendicular to the longitudinal axis of said strip, the frequency of said lines being greatest adjacent to points along said fluorescent tube where the light output is greatest, the frequency of said lines being lower at points along said fluorescent tube where the light output is least.
Claim 9
Dependent Claim
26 words
The imaging system in accordance with claim 7 wherein said strip is coated with a photographic emulsion and said lines are produced by a photographic technique.
Claim 10
Dependent Claim
63 words
The imaging system in accordance with claim 6 wherein said pattern includes a plurality of opaque spaced apart lines perpendicular to the longitudinal axis of said strip, the frequency of said lines being greatest at a point adjacent to the center of said fluorescent tube and decreasing in frequency as points along the strip adjacent to the ends of the tube are approached.
Claim 11
Dependent Claim
21 words
The imaging system in accordance with claim 9 wherein said strip is positioned tangential to the surface of said fluorescent tube.
Claim 12
Dependent Claim
31 words
The imaging system in accordance with claim 9 wherein said fluorescent tube has an aperture and said mask means covers the entire aperture along the entire length of said fluorescent tube.
Claim 13
Dependent Claim
56 words
A mask for controlling image plane light level distribution from a source of illumination, said mask comprising a clear substrate, said substrate coated with a plurality of opaque lines, the frequency of said lines increasing in areas adjacent to the image plane where it is desired to decrease the amount of light reaching the image plane.
Claim 14
Dependent Claim
56 words
A mask for controlling image plane light level distribution from a source of illumination, said mask comprising a clear substrate, said substrate coated with a plurality of opaque lines, the frequency of said lines increasing in areas adjacent to the image plane where it is desired to decrease the amount of light reaching the image plane.
Claim 15
Dependent Claim
41 words
The mask in accordance with claim 12 wherein said substrate is coated with a photographic emulsion, and said lines are produced by first projecting a pattern corresponding to the desired line distribution onto said coated strip and then developing said emulsion.
Claim 16
Dependent Claim
82 words
The mask in accordance with claim 12 wherein said source of illumination is a fluorescent tube and said mask is in the shape of a strip, said plurality of opaque lines running perpendicular to the longitudinal axis of said strip, said strip positioned parallel to and between said fluorescent tube and said image plane, the frequency of said lines being greatest in an area adjacent to the center of said fluorescent tube and decreasing as the ends of said strip are approached.
Claim 17
Dependent Claim
85 words
A line scan optical imaging system for scanning a line of a document comprising: means for illuminating said line of said document; mirror means for transmitting light reflected from said document line; lens means for receiving a focusing light transmitted by said mirror means; photo-optical means for converting said focused light into a plurality of electrical signals; and mask means, positioned between said illuminating means and said document line, for blocking portions of the light output from said illuminating means from reaching said document line.
Claim 18
Dependent Claim
85 words
A line scan optical imaging system for scanning a line of a document comprising: means for illuminating said line of said document; mirror means for transmitting light reflected from said document line; lens means for receiving a focusing light transmitted by said mirror means; photo-optical means for converting said focused light into a plurality of electrical signals; and mask means, positioned between said illuminating means and said document line, for blocking portions of the light output from said illuminating means from reaching said document line.
Claim 19
Dependent Claim
62 words
The line scan imaging system in accordance with claim 15 wherein: said illuminating means includes at least one fluorescent tube; and said mask means is a linear strip mask positioned between said fluorescent tube and said document, said strip mask including a clear substrate coated with a plurality of spaced apart opaque areas running perpendicular to the longitudinal axis of said substrate.
Claim 20
Dependent Claim
50 words
The line scan imaging system in accordance with claim 16 wherein each of said opaque areas is a line, the frequency of said lines being greatest at an area near the center of said fluorescent tube and decreasing in frequency as the ends of said linear strip mask are approached.
Claim 21
Dependent Claim
49 words
The line scan imaging system in accordance with claim 17 wherein said illuminating means includes two of said fluorescent tubes, each of said tubes being of an aperture type and wherein the aperture area of each of said fluorescent tubes has one of said strip masks next to it.
Claim 22
Dependent Claim
49 words
The line scan imaging system in accordance with claim 18 wherein said mirror means is of the folded mirror type and said photo-optical means includes a large number of photoelectric conversion elements arranged in a line, each element receiving focused light from a unit area of said document line.
Claim 23
Dependent Claim
39 words
A mask for modifying the output of a source of illumination, said mask comprising a clear substrate coated with a plurality of opaque lines, said opaque lines for blocking portions of the light output by said source of illumination.
Claim 24
Dependent Claim
39 words
A mask for modifying the output of a source of illumination, said mask comprising a clear substrate coated with a plurality of opaque lines, said opaque lines for blocking portions of the light output by said source of illumination.
References Cited (Backward Citations)
No citation records indexed.
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