Patent US3868637A successfully refreshed from Google Patents.
US3868637A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Document retrieval system
Assignee: Individual
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Filing: 1973-09-19
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Granted: 1975-02-25
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Expires: 1993-09-19
Abstract
Abstract An automatic retrieval system for locating desired frames of microfilm wherein each frame may be randomly located along a strip of microfilm. The coding employed is the use of humanly readable symbols, such as alpha-numeric characters, deployed along the margin of each side of each frame. The symbols are transparent against an opaque background and are small enough so that they will significantly diffract light. First and second rectangular beams of laser light scan first and second margins to provide a Fraunhofer diffraction pattern for each symbol. The Fraunhofer diffraction pattern is projected onto an array of photocells to provide a unique set of signals to indicate each symbol. Thus, each symbol is a byte, rather than a bit. A unique center symbol is used. A rectangular beam is developed from a circular laser generator output by compression in one direction through two cylindrical lenses to provide an elliptical beam. The elliptical beam impinges on a plate having a central slit to form a rectangular beam. The light on the slit is further processed and transmitted onto the film margin. A beam splitter splits the transmitted light into two beams, one for each margin on the film. The center symbols on opposite margins are orthogonally read to provide output signals which are nominally displaced 90* from one another so that direction of movement of film can be sensed and controlled. The code along each margin is replicated to improve signal to noise, reduce ambiguity and reduce erroneous readings.
Inventors
- 👤 Michael S Schiller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:06
CPC Classifications
G; G06; G06K; G06K17/00; G06K17/0016; G06K17/0019
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
203 words
In an automatic document retrieval system for reading a film at a predetermined plane, the interrogating light beam generating apparatus comprising: light source means to provide a beam of spatially coherent light circular in cross-section and having a frist cross-sectional area, first and second cylindrical lenses optically downstream from said light source means to convert said circular light beam into a collimated eliptical light beam having a second crosssectional area less than said first cross-sectional area, a plate having an opening of a desired reading window configuration at the back focal plane of the optically downstream one of said cylindrical lenses, first and second spherical lenses downstream from said plate to process and transmit the diffracted light beam from said opening, said opening being at the front focal plane of said first spherical lens, the back focal plane of said first spherical lens being substantially coincident with the front focal plane of said second spherical lens, the back focal point of said second lens being coincident with the predetermined plane of the film at which the information to be read is located, the sole image created at said predetermined plane being an image of the light transmitted through said opening in said plate.
Claim 2
Dependent Claim
203 words
In an automatic document retrieval system for reading a film at a predetermined plane, the interrogating light beam generating apparatus comprising: light source means to provide a beam of spatially coherent light circular in cross-section and having a frist cross-sectional area, first and second cylindrical lenses optically downstream from said light source means to convert said circular light beam into a collimated eliptical light beam having a second crosssectional area less than said first cross-sectional area, a plate having an opening of a desired reading window configuration at the back focal plane of the optically downstream one of said cylindrical lenses, first and second spherical lenses downstream from said plate to process and transmit the diffracted light beam from said opening, said opening being at the front focal plane of said first spherical lens, the back focal plane of said first spherical lens being substantially coincident with the front focal plane of said second spherical lens, the back focal point of said second lens being coincident with the predetermined plane of the film at which the information to be read is located, the sole image created at said predetermined plane being an image of the light transmitted through said opening in said plate.
Claim 3
Dependent Claim
36 words
The apparatus of claim 1 further comprising: a spatial filter at the back focal plane of said first spherical lens to transmit the diffraction pattern of said opening of said plate and to block scattered light.
Claim 4
Dependent Claim
308 words
In an automatic document retrieval system, the improvement of a means to provide a beam of spatially coherent light for reading a film comprising: a light source providing a collimated beam of light having a first cross-sectional area, first and second lenses optically downstream from said light source, said first and second lenses transforming and imaging said light beam into a collimated light beam having a predetermined cross-sectional shape and a second cross-sectional area less than said first cross-sectional area, said first and second lenses compressing said light beam in at least one axis, a plate having an opening of a desired reading Window configuration at the back focal plane of the optically downstream one of said first and second lenses, said predetermined cross-sectional shape of said light beam incident on said opening providing substantially increased light transmission through said opening than would be provided if the light beam from said light source were incident on said opening without being shaped by said first and second lenses, a predetermined plane at which the film to be read is positioned, third and fourth lenses downstream from said plate and positioned to process and transmit the diffracted light beam from said opening to provide an exact replica of the light content of said opening in said plate at said predetermined plane, said third and fourth lenses being spherical, the back focal plane of said third spherical lens being substantially coincident with the front focal plane of said fourth spherical lens, said opening in said plate being substantially at the front focal plane of said third spherical lens, and the back focal point of said fourth lens being substantially coincident with said predetermined place of the film to be read, the sole image created at said predetermined plane being an image of the light transmitted through said opening in said plate.
Claim 5
Dependent Claim
308 words
In an automatic document retrieval system, the improvement of a means to provide a beam of spatially coherent light for reading a film comprising: a light source providing a collimated beam of light having a first cross-sectional area, first and second lenses optically downstream from said light source, said first and second lenses transforming and imaging said light beam into a collimated light beam having a predetermined cross-sectional shape and a second cross-sectional area less than said first cross-sectional area, said first and second lenses compressing said light beam in at least one axis, a plate having an opening of a desired reading Window configuration at the back focal plane of the optically downstream one of said first and second lenses, said predetermined cross-sectional shape of said light beam incident on said opening providing substantially increased light transmission through said opening than would be provided if the light beam from said light source were incident on said opening without being shaped by said first and second lenses, a predetermined plane at which the film to be read is positioned, third and fourth lenses downstream from said plate and positioned to process and transmit the diffracted light beam from said opening to provide an exact replica of the light content of said opening in said plate at said predetermined plane, said third and fourth lenses being spherical, the back focal plane of said third spherical lens being substantially coincident with the front focal plane of said fourth spherical lens, said opening in said plate being substantially at the front focal plane of said third spherical lens, and the back focal point of said fourth lens being substantially coincident with said predetermined place of the film to be read, the sole image created at said predetermined plane being an image of the light transmitted through said opening in said plate.
Claim 6
Dependent Claim
59 words
The improvement of claims 3 wherein: said light source provides a beam substantially circular in cross-section, said first and second lenses are cylindrical lenses and convert said circular light beam into an eliptical light beam, said opening at said plate is rectangular and has dimensions that fit within the cross-section of said elliptical light beam incident on said plate.
Claim 7
Dependent Claim
24 words
The improvement of claim 3 wherein the geometric shape of said opening of said plate encompasses the information to be read on the film.
Claim 8
Dependent Claim
40 words
The improvement of claim 3 further comprising: a spatial filter substantially at the back focal plane of said third lens, the geometry of said spatial filter transmitting the diffraction pattern of said opening of said plate and blocking scattered light.
Claim 9
Dependent Claim
40 words
The improvement of claim 4 further comprising: a spatial filter substantially at the back focal plane of said third lens, the geometry of said spatial filter transmitting the diffraction pattern of said opening of said plate and blocking scattered light.
Claim 10
Dependent Claim
40 words
The improvement of claim 5 further comprising: a spatial filter substantially at the back focal plane of said third lens, the geometry of said spatial filter transmitting the diffraction pattern of said opening of said plate and blocking scattered light.
References Cited (Backward Citations)
US3210468A
Cited
US3803353A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-24 | 1978-08-26 | 1979-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-24 | 1982-08-26 | 1983-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-24 | 1986-08-26 | 1987-02-25 | $7700.00 | Window Closed / Lapsed |