Abstract A laser page scanner is disclosed in which the information bearing sheet to be scanned is disposed in a cylinder which translates axially past an opto-mechanical scanning apparatus fixed coaxially within the cylinder. A laser beam is directed from outside the cylinder along a path parallel to the cylinder axis into the interior of the cylinder where it is redirected by relay mirrors to the cylinder axis and to a rotating mirror which reflects the beam radially outwardly whereby the beam scans the cylinder in a continuous circle. As a result of the longitudinal translation of the cylinder, the document is, in effect, line scanned. The light reflected back to the rotating mirror at a given instant is an analog of information which is present at the scanned spot. The reflected light is redirected by the rotating mirror back along the axis of the cylinder through a pair of spot forming lenses to a first photo-diode which is utilized as the input sensor to suitable electronics for storing or reproducing the scanned information. A second photo-diode is fixed radially outwardly from the rotating mirror in order to intercept the laser beam once each revolution of the rotating mirror to provide a synch signal. A circular mask is disposed between the first photo-diode and the nearest spot forming lens to prevent a selected core portion of the beam from reaching the photo-diode to improve the signal-to-noise ratio. In order to simplify the optical system, one of the relay mirrors is cemented to the center of the spot forming lens nearest the first photo-diode to redirect the laser beam through the other spot forming lens before it impinges on the rotating mirror.
Inventors
👤 Randy J Sherman
👤 Derald F Hanson
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-23 15:49
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/02; H04N3/08
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
310 words
Apparatus for scanning an information bearing document and developing an electrical signal which is an analog of the information comprising: a. a tubular document holding cylinder, said cylinder including means for supporting a document concentrically with respect to and in light receiving relationship to the axis of said cylinder; b. a light source for directing a collimated beam of light in a path parallel to said axis into the interior of said cylinder; c. a first relay mirror for receiving said collimated beam and redirecting it in the path which intercepts said axis; d. a second relay mirror for receiving said collimated beam from said mirror and redirecting it in a path coinciding with said axis; e. a 45* scan mirror rotatable about said axis and oriented to deflect said beam radially outwardly from said axis toward said document; f. means for rotating said mirror about said axis; g. a first beam converging lens disposed concentrically with respect to said cylinder and between said second relay mirror and said scan mirror, said first beam converging lens having a focal length equal to the sum of the distances between said first beam converging lens and said rotating mirror and between said rotating mirror and said document in order to focus said collimated beam on said document, said first beam converging lens also receiving and collimating light reflected from said document onto said rotating mirror; h. a first light sensitive sensor responsive to variations in the intensity of light for deriving an electrical signal analogous to the instantaneous light intensity; and i. a second beam converging lens disposed concentrically with respect to said cylinder and between said first beam converging lens and said first light sensitive sensor, said second beam converging lens having a focal length equal to the distance between said second beam converging lens and said first light sensitive sensor.
Claim 2
Dependent Claim
310 words
Apparatus for scanning an information bearing document and developing an electrical signal which is an analog of the information comprising: a. a tubular document holding cylinder, said cylinder including means for supporting a document concentrically with respect to and in light receiving relationship to the axis of said cylinder; b. a light source for directing a collimated beam of light in a path parallel to said axis into the interior of said cylinder; c. a first relay mirror for receiving said collimated beam and redirecting it in the path which intercepts said axis; d. a second relay mirror for receiving said collimated beam from said mirror and redirecting it in a path coinciding with said axis; e. a 45* scan mirror rotatable about said axis and oriented to deflect said beam radially outwardly from said axis toward said document; f. means for rotating said mirror about said axis; g. a first beam converging lens disposed concentrically with respect to said cylinder and between said second relay mirror and said scan mirror, said first beam converging lens having a focal length equal to the sum of the distances between said first beam converging lens and said rotating mirror and between said rotating mirror and said document in order to focus said collimated beam on said document, said first beam converging lens also receiving and collimating light reflected from said document onto said rotating mirror; h. a first light sensitive sensor responsive to variations in the intensity of light for deriving an electrical signal analogous to the instantaneous light intensity; and i. a second beam converging lens disposed concentrically with respect to said cylinder and between said first beam converging lens and said first light sensitive sensor, said second beam converging lens having a focal length equal to the distance between said second beam converging lens and said first light sensitive sensor.
Claim 3
Dependent Claim
24 words
The apparatus of claim 1 which further includes means for providing mutual axial translation between said tubular document holding cylinder and said rotating mirror.
Claim 4
Dependent Claim
42 words
The apparatus of claim 2 which further includes a second light sensitive sensor fixed in position with respect to said rotating mirror in order to intercept said beam of light once each revolution of said rotating mirror to provide a synch pulse.
Claim 5
Dependent Claim
20 words
The apparatus of claim 1 in which said second relay mirror is fixed directly to said second beam converging lens.
Claim 6
Dependent Claim
91 words
The apparatus of claim 3 which further includes a masking disc suspended between said second beam converging lens and said first light sensitive sensor and disposed concentrically with respect to said cylinder, said masking disc having a diameter less than the diameter of the converging beam at is position between said second beam converging lens and said first light sensitive sensor such that only the portion of the converging beam directed toward said first light sensitive sensor beyond the periphery of said masking disc impinges upon said first light sensitive sensor.