US4352984A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light beam scanning device
Assignee: Fujifilm Holdings Corp
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Filing: 1980-06-13
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Granted: 1982-10-05
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Expires: 2000-06-13
Abstract
Abstract A light beam scanning device in which a light beam is scanned over an image or recording surface at a constant velocity independent of beam position and disturbances in the drive to the system. A position detecting device produces a signal representing the position of the light beam over the surface with the light beam being scanned by an optical deflector device. A feedback loop such as a phase-locked loop controls the movement of the optical deflector in response to a signal produced by the position detecting device and a reference signal.
Inventors
- 👤 Yuji Ohara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:41
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/04; H04N1/047; H04N1/053; H04N1/113; H04N1/1135; H04N2201/00; H04N2201/024; H04N2201/02406; H04N2201/02416; H04N2201/02439; H04N2201/02441; H04N2201/02443; H04N2201/04; H04N2201/047; H04N2201/04701; H04N2201/0471; H04N2201/04729; H04N2201/04731; H04N2201/04734; H04N2201/04744; H04N2201/04753; H04N2201/04755; H04N2201/04789; H04N2201/04791; H04N2201/04794; H04N2201/04796; H04N2201/04798
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
113 words
A light beam scanning device comprising: a light beam comprised of a main laser beam and a reference laser beam having a different wavelength from that of said main laser beam, said main laser beam and said reference laser beam being projected along a common path; means for scanning said light beam over a surface; position detecting means responsive to said reference laser beam for detecting a position of said light beam over said surface to be scanned; and feedback loop means for controlling said optical deflector in response to a signal outputted by said position detecting means to cause said light beam to scan said surface to be scanned at a constant
Claim 2
Dependent Claim
113 words
A light beam scanning device comprising: a light beam comprised of a main laser beam and a reference laser beam having a different wavelength from that of said main laser beam, said main laser beam and said reference laser beam being projected along a common path; means for scanning said light beam over a surface; position detecting means responsive to said reference laser beam for detecting a position of said light beam over said surface to be scanned; and feedback loop means for controlling said optical deflector in response to a signal outputted by said position detecting means to cause said light beam to scan said surface to be scanned at a constant
Claim 3
Dependent Claim
103 words
The light beam scanning device of claim 1 wherein said feedback loop comprises means for amplifying said signal outputted by said position detecting means; a difference detector to one input of which an output of said amplifying means is coupled; a sawtooth wave generator having an output coupled to a second input of said difference detector; a correction circuit having a first input coupled to an output of said difference detector and a second input coupled to said output of said sawtooth wave generator; and a drive circuit for operating said scanning means operating in response to an output of said correction circuit.
Claim 4
Dependent Claim
365 words
A light beam scanning device comprising: means for scanning a light beam over a surface in a first direction; first position detecting means for detecting a position of said light beam over said surface; a first phase comparator having a first input coupled to receive an output signal produced by said first position detecting means; a first pulse generator producing pulses of a constant frequency, an output of said first pulse generator being coupled to a second input of said first phase comparator; a first low-pass filter having an input coupled to an output of said first phase comparator; a first voltage amplifier having an input coupled to an output of said first low-pass filter; a first voltage controlled oscillator having an input coupled to an output of said first voltage amplifier; a first binary counter having a count input coupled to an output of said first voltage controlled oscillator; a first digital-to-analog converter having binary inputs coupled to corresponding outputs of said first counter; a first drive circuit having an input coupled to an output of said digital-to-analog converter and having an output coupled to operate said first scanning means; second position detecting means for detecting the position of said light beam over said surface in a second direction; a second phase comparator having a first input coupled to receive an output signal from said second position detecting means; a second pulse generator producing pulses of constant frequency, an output of said pulse generator being coupled to a second input of said second phase comparator; a second low-pass filter having an input coupled to an output of said second phase comparator; a second voltage amplifier having an input coupled to an output of said second low-pass filter; a second voltage controlled oscillator having an input coupled to an output of said second voltage amplifier; a second binary counter having a count input coupled to an output of said second voltage controlled oscillator; a second digital-to-analog converter having binary inputs coupled to corresponding binary outputs of said second counter; a second drive circuit having an input coupled to an output of said digital-to-analog converter and having an output coupled to operate said second scanning means.
Claim 5
Dependent Claim
365 words
A light beam scanning device comprising: means for scanning a light beam over a surface in a first direction; first position detecting means for detecting a position of said light beam over said surface; a first phase comparator having a first input coupled to receive an output signal produced by said first position detecting means; a first pulse generator producing pulses of a constant frequency, an output of said first pulse generator being coupled to a second input of said first phase comparator; a first low-pass filter having an input coupled to an output of said first phase comparator; a first voltage amplifier having an input coupled to an output of said first low-pass filter; a first voltage controlled oscillator having an input coupled to an output of said first voltage amplifier; a first binary counter having a count input coupled to an output of said first voltage controlled oscillator; a first digital-to-analog converter having binary inputs coupled to corresponding outputs of said first counter; a first drive circuit having an input coupled to an output of said digital-to-analog converter and having an output coupled to operate said first scanning means; second position detecting means for detecting the position of said light beam over said surface in a second direction; a second phase comparator having a first input coupled to receive an output signal from said second position detecting means; a second pulse generator producing pulses of constant frequency, an output of said pulse generator being coupled to a second input of said second phase comparator; a second low-pass filter having an input coupled to an output of said second phase comparator; a second voltage amplifier having an input coupled to an output of said second low-pass filter; a second voltage controlled oscillator having an input coupled to an output of said second voltage amplifier; a second binary counter having a count input coupled to an output of said second voltage controlled oscillator; a second digital-to-analog converter having binary inputs coupled to corresponding binary outputs of said second counter; a second drive circuit having an input coupled to an output of said digital-to-analog converter and having an output coupled to operate said second scanning means.
Claim 6
Dependent Claim
29 words
The light beam scanning device of claim 3 wherein said first and second position detecting means each comprise a linear encoder, at least one lens, and an optical detector.
Claim 7
Dependent Claim
48 words
The light beam scanning device of claim 1 wherein said light beam comprises a main laser beam and a reference laser beam having a different wavelength from that of said main laser beam, said main laser beam and said reference laser beam being projected along a common path.
Claim 8
Dependent Claim
30 words
The light beam scanning device of claim 1 or 3 wherein said scanning means comprises a beam splitting mirror and a galvanometer drive operatively coupled to said beam splitting mirror.
References Cited (Backward Citations)
US4140903A
Cited
US4178064A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-10-04 | 1986-04-05 | 1986-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-10-04 | 1990-04-05 | 1990-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-10-04 | 1994-04-05 | 1994-10-05 | $7700.00 | Window Closed / Lapsed |