US3873180A
Expired / Lapsed
US
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Light beam scanning system with scan angle demagnification
Assignee: Ampex Corp
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Filing: 1973-09-10
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Granted: 1975-03-25
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Expires: 1993-09-10
Abstract
Abstract Specific arrangements of optical elements are utilized in various demagnifier embodiments to provide scan angle demagnification of a scanning beam in a light scan system which utilizes a rotating mirror polygon, and further beam redirecting optics, to produce the scan. Scan angle demagnification may be achieved by locating the rotating mirror polygon within the beam redirecting optical means relative to a spot forming lens to provide a ratio of conjugates, and thus a final scan angle of proportionately smaller angle than the initial scan angle. That is, the initial scan beam reflected from the rotating mirror polygon to the elements of the beam redirecting optics form an angle theta with respect to the optical axis of the system. Upon traverse of the beam redirecting optical elements, the resulting scan beam crosses the optical axis again at a point beyond the beam redirecting optics at a smaller angle phi , thus providing a final scan beam with scan angle demagnification. The invention may employ negative and positive reflector and/or refractor lens elements in association with, or as part of, the beam redirecting optics, to provide the scan angle demagnification effect. In the invention combination, selected refractor lens elements inherently provide a nonlinear distortion, which is utilized to advantage to make the spot position on the focal plane substantially a linear function of the tangent of the field angle. The distortion correction may further be utilized to advantage to produce a flat focal field, and thus a flat scan line at the recording medium.
Inventors
- 👤 Samuel Bousky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:05
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/0025; G02B27/0031; G02B26/00; G02B26/08; G02B26/10; G02B26/12; G02B26/125; G02B26/126
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
137 words
An improved light beam scanning system capable of substantially diffraction limited performance, for scanning data in the form of lines on a medium during record, display and readout processes, and having at least one entrant light beam, comprising the combination of: rotating mirror means formed of at least one mirror surface disposed to receive the entrant light beam and to generate an initial scan beam of a selected initial angular scan with a pivot point substantially at the mirror surface; optical beam directing means disposed to receive the initial scan beam and to generate a final scan beam of substantially reduced angular scan relative to the initial angular scan; and spot forming lens means disposed to receive the beam of reduced angular scan and to form a focussed scan spot within a correspondingly reduced angular scan field.
Claim 2
Dependent Claim
137 words
An improved light beam scanning system capable of substantially diffraction limited performance, for scanning data in the form of lines on a medium during record, display and readout processes, and having at least one entrant light beam, comprising the combination of: rotating mirror means formed of at least one mirror surface disposed to receive the entrant light beam and to generate an initial scan beam of a selected initial angular scan with a pivot point substantially at the mirror surface; optical beam directing means disposed to receive the initial scan beam and to generate a final scan beam of substantially reduced angular scan relative to the initial angular scan; and spot forming lens means disposed to receive the beam of reduced angular scan and to form a focussed scan spot within a correspondingly reduced angular scan field.
Claim 3
Dependent Claim
23 words
The scanning system of claim 1 wherein the optical beam directing means reimages the pivot point substantially at the spot forming lens means.
Claim 4
Dependent Claim
45 words
The scanning system of claim 2 wherein the rotating mirror means and the spot forming lens means are situated at the extremes of conjugates of different lengths relative to the beam directing means, wherein the reduction in scan angle is proportional to the conjugate ratio.
Claim 5
Dependent Claim
67 words
The scanning system of claim 3 wherein the beam directing means includes, demaGnifier means comprising refractor lens elements located between the initial and final scan beams to generate the final scan beam of reduced scan field angle, wherein the effective conjugates of the beam directing means determine the reimaged pibot point position at the spot forming lens means while determining the ratio of scan field angle reduction.
Claim 6
Dependent Claim
51 words
The scanning system of claim 4 including a flat medium wherein the refractor lens elements define a Galilean type telescope with inherent nonlinear distortion, said refractor lens elements disposed to provide the scan spot position on the flat medium as a substantially linear function of the tangent of the field angle.
Claim 7
Dependent Claim
52 words
The scanning system of claim 4 wherein the beam directing means further comprises, catadioptric means operatively disposed to receive the initial scan beam and to pre-image the pivot point thereof to a selected pre-image point spaced therefrom, said demagnifier means being disposed to receive the initial scan beam from the catadioptric means.
Claim 8
Dependent Claim
50 words
The scanning system of claim 6 wherein the pre-imaged pibot point is disposed within a range extending before, to within, the refractor lens elements of said demagnifier means, said refractor lens elements being further selectively spaced to direct the beam of reduced scan angle to the spot forming lens means.
Claim 9
Dependent Claim
67 words
The scanning system of claim 2 including a flat medium, wherein said optical beam directing means includes demagnifier means for reimaging the pivot point, said demagnifier means including nonlinear distortion which provides a scan spot position on the reduced angular scan field which is substantially a linear function of the tangent of the field angle and which thus traces a flat scan line across the flat medium.
Claim 10
Dependent Claim
56 words
The scanning system of claim 8 wherein the demagnifier means reimages the pivot point substantially at the spot forming lens means, and said beam directing means further includes catadioptric means disposed between the rotating mirror means and the demagnifier means for preimaging the pivot point to a pre-image point spaced therefrom prior to the demagnifier means.
Claim 11
Dependent Claim
25 words
The scanning system of claim 9 wherein the demagnifier means includes, a plurality of refractor elements having selected thicknesses, spacings, radii and indices of refraction.
Claim 12
Dependent Claim
59 words
The scanning system of claim 8 wherein the demagnifier means reimages the pivot point immediately prior to the spot forming lens means, and said beam directing means further includes pivotable mirror means disposed to intercept the beam of reduced scan angle at the reimaged point, to impart movement to the beam in a direction normal to the scan direction.
Claim 13
Dependent Claim
118 words
In a light beam scanning system having at least one entrant beam, a rotary polygon of multiple mirror surfaces for generating an initial beam scan of selected initial scan angle; a beam scan demagnifier means comprising optical lens elements having surfaces of substantially spherical curvature and disposed to generate a final scan beam of reduced scan angle; and spot forming lens means disposed to receive the beam of reduced scan angle to form a focussed scan spot within the correspondingly reduced angular scan field; said demagnifier means providing optical means for decreasing the number of mirror surfaces on the rotary polygon while simultaneously decreasing the beam scan angle to the spot forming lens to facilitate fabricating the latter.
Claim 14
Dependent Claim
118 words
In a light beam scanning system having at least one entrant beam, a rotary polygon of multiple mirror surfaces for generating an initial beam scan of selected initial scan angle; a beam scan demagnifier means comprising optical lens elements having surfaces of substantially spherical curvature and disposed to generate a final scan beam of reduced scan angle; and spot forming lens means disposed to receive the beam of reduced scan angle to form a focussed scan spot within the correspondingly reduced angular scan field; said demagnifier means providing optical means for decreasing the number of mirror surfaces on the rotary polygon while simultaneously decreasing the beam scan angle to the spot forming lens to facilitate fabricating the latter.
Claim 15
Dependent Claim
56 words
The beam scan demagnifier means of claim 12 wherein said demagnifier means includes inherent nonlinear distortion, which in combination with the spot forming lens means provides the scan spot position on the reduced angular scan field which is substantially a linear function of the tangent of the field angle to thus trace a flat scan field.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |