US5138340A
Expired / Lapsed
US
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Temperature controlled light source for interlaced printer
Assignee: Xerox Corp
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Filing: 1990-12-06
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Granted: 1992-08-11
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Expires: 2010-12-06
Abstract
Abstract A technique for producing pixel patterns at different selected wavelengths. A diode laser is repeatedly pulsed and has its temperature changed from pulse to pulse, which causes the output wavelength to change. This allows pixel patterns to be interlaced by the use of dispersive elements such as prisms in the optical train. A temperature shift of about 15° C. provides a wavelength shift of about 30 angstroms, which is usable. A temperature shift of 20° C.-30° C. or more is preferable. The temperature shifts may be accomplished by supplying specific currents below threshold and above threshold. For two-wavelength operation, the laser is driven at a first bias current below threshold for a first non-illumination interval, at a first pulse current above threshold for a first illumination interval, at a second bias current below threshold for a second non-illumination interval, and a second pulse current above threshold for a second illumination interval. The bias currents are sufficiently different so as to establish different operating temperatures for the illumination intervals. The temperature shifts may also be accomplished at least in part by use of an auxiliary heater.
Inventors
- 👤 Robert A. Sprague
- 👤 Mark S. Bernstein
- 👤 Robert P. Kowalski
- 👤 David L. Hecht
- 👤 David L. Steinmetz
- 👤 David E. Kizer
- 👤 Robert L. Thornton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 04:57
CPC Classifications
G; G06; G06K; G06K15/00; G06K15/02; G06K15/12
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
152 words
In a printer having a diode laser and control electronics for applying data signals to a beam emitted by the laser, the improvement comprising: means, synchronized with the control electronics, for establishing a series of sequences, each sequence including a first non-illumination interval, a first illumination interval, a second non-illumination interval, and a second illumination interval; means, operable for each sequence of the series, for passing first and second pulse currents through the laser during respective first and second illumination intervals; and means, operable during at least one of the first and second non-illumination intervals of each sequence of the series, for establishing different first and second operating temperatures of the laser for the first and second illumination intervals; whereby the laser emits light during the first and second illumination intervals at different wavelengths due at least in part to the different operating temperatures established during the first and second non-illumination intervals.
Claim 2
Dependent Claim
152 words
In a printer having a diode laser and control electronics for applying data signals to a beam emitted by the laser, the improvement comprising: means, synchronized with the control electronics, for establishing a series of sequences, each sequence including a first non-illumination interval, a first illumination interval, a second non-illumination interval, and a second illumination interval; means, operable for each sequence of the series, for passing first and second pulse currents through the laser during respective first and second illumination intervals; and means, operable during at least one of the first and second non-illumination intervals of each sequence of the series, for establishing different first and second operating temperatures of the laser for the first and second illumination intervals; whereby the laser emits light during the first and second illumination intervals at different wavelengths due at least in part to the different operating temperatures established during the first and second non-illumination intervals.
Claim 3
Dependent Claim
42 words
The improvement of claim 1 wherein the first and second pulse currents have respective magnitudes and the first and second illumination intervals have respective durations such that total energy emitted by the laser is identical for the first and second illumination intervals.
Claim 4
Dependent Claim
18 words
The improvement of claim 1 wherein the first pulse current is substantially constant during the first illumination interval.
Claim 5
Dependent Claim
15 words
The improvement of claim 1 wherein the sequences occur without intervening time intervals between sequences.
Claim 6
Dependent Claim
68 words
The improvement of claim 1 wherein the means for establishing different first and second operating temperatures comprises means for passing first and second bias currents through the laser during the respective first and second non-illumination intervals, the first and second bias currents being below threshold and being sufficiently different so as to establish at least a significant portion of the difference between the first and second operating temperatures.
Claim 7
Dependent Claim
38 words
The improvement of claim 5 wherein the laser is characterized by a sufficiently high threshold current and thermal impedance that the first and second bias currents differ sufficiently that the operating temperatures differ by at least 15° C.
Claim 8
Dependent Claim
41 words
The improvement of claim 1 wherein the means for establishing different first and second operating temperatures comprises: an external heater thermally coupled to the laser; and means for energizing the heater during only one of the first and second non-illumination intervals.
Claim 9
Dependent Claim
13 words
The improvement of claim 1 wherein the printer includes an optical image bar.
Claim 10
Dependent Claim
39 words
The improvement of claim 8 wherein the printer includes at least one dispersive element in the path of the beam emitted by the source so as to provide a lateral offset between pixel patterns resulting from the different wavelengths.
Claim 11
Dependent Claim
14 words
The improvement of claim 1 wherein the wavelengths differ by at least 30 angstroms.
Claim 12
Dependent Claim
39 words
The improvement of claim 1 wherein the printer includes at least one dispersive element in the part of the beam emitted by the laser so as to provide a lateral offset between printed patterns resulting from the different wavelengths.
Claim 13
Dependent Claim
16 words
The improvement of claim 1 wherein the first pulse current decreases during the first illumination interval.
Claim 14
Dependent Claim
22 words
The improvement of claim 1 wherein the first pulse current comprises a plurality of spaced pulses occurring during the first illumination interval.
Claim 15
Dependent Claim
167 words
In a printer a having a diode laser characterized by a threshold and control electronics for applying data signals to a beam emitted by the laser, the improvement comprising: means, synchronized with the control electronics, for establishing a series of sequences, each sequence including a first non-illumination interval, a first illumination interval, a second non-illumination interval, and a second illumination interval; and means, operable for each sequence of the series, for passing first bias, first pulse, second bias, and second pulse currents through the laser during respective first non-illumination, first illumination, a second non-illumination, and second illumination intervals, the first and second bias currents being below the threshold of the laser and the first and second pulse currents being above the threshold of the laser; the first and second bias currents being sufficiently different to establish different operating temperatures for the first and second illumination intervals; whereby the laser emits light during the first and second illumination intervals at different wavelengths due to the different operating temperatures.
Claim 16
Dependent Claim
167 words
In a printer a having a diode laser characterized by a threshold and control electronics for applying data signals to a beam emitted by the laser, the improvement comprising: means, synchronized with the control electronics, for establishing a series of sequences, each sequence including a first non-illumination interval, a first illumination interval, a second non-illumination interval, and a second illumination interval; and means, operable for each sequence of the series, for passing first bias, first pulse, second bias, and second pulse currents through the laser during respective first non-illumination, first illumination, a second non-illumination, and second illumination intervals, the first and second bias currents being below the threshold of the laser and the first and second pulse currents being above the threshold of the laser; the first and second bias currents being sufficiently different to establish different operating temperatures for the first and second illumination intervals; whereby the laser emits light during the first and second illumination intervals at different wavelengths due to the different operating temperatures.
Claim 17
Dependent Claim
42 words
The improvement of claim 14 wherein the first and second pulse currents have respective magnitudes and the first and second illumination intervals have respective durations such that total energy emitted by the laser is identical for the first and second illumination intervals.
Claim 18
Dependent Claim
18 words
The improvement of claim 14 wherein the first pulse current is substantially constant during the first illumination interval.
Claim 19
Dependent Claim
15 words
The improvement of claim 14 wherein the sequences occur without intervening time intervals between sequences.
Claim 20
Dependent Claim
38 words
The improvement of claim 14 wherein the laser is characterized by a sufficiently high threshold current and thermal impedance that the first and second bias currents differ sufficiently that the operating temperatures differ by at least 15° C.
Claim 21
Dependent Claim
14 words
The improvement of claim 14 wherein the wavelengths differ by at least 30 angstroms.
Claim 22
Dependent Claim
39 words
The improvement of claim 14 wherein the printer includes at least one dispersive element in the part of the beam emitted by the laser so as to provide a lateral offset between printed patterns resulting from the different wavelengths.
Claim 23
Dependent Claim
16 words
The improvement of claim 14 wherein the first pulse current decreases during the first illumination interval.
Claim 24
Dependent Claim
22 words
The improvement of claim 14 wherein the first pulse current comprises a plurality of spaced pulses occurring during the first illumination interval.
Claim 25
Independent Claim
137 words
A method of operating a diode laser comprising the steps of: establishing a series of sequences, each sequence including a first non-illumination interval, a first illumination interval, a second non-illumination interval, and a second illumination interval; for each sequence of the series, passing first and second pulse currents through the laser during respective first and second illumination intervals, the first and second pulse currents being above the threshold of the laser; and for each sequence of the series, establishing different first and second operating temperatures for the first and second illumination intervals, said establishing step being performed during at least one of the first and second non-illumination intervals; whereby the laser emits light during the first and second illumination intervals at different wavelengths due to the different operating temperatures established during the first and second non-illumination intervals.
Claim 26
Independent Claim
137 words
A method of operating a diode laser comprising the steps of: establishing a series of sequences, each sequence including a first non-illumination interval, a first illumination interval, a second non-illumination interval, and a second illumination interval; for each sequence of the series, passing first and second pulse currents through the laser during respective first and second illumination intervals, the first and second pulse currents being above the threshold of the laser; and for each sequence of the series, establishing different first and second operating temperatures for the first and second illumination intervals, said establishing step being performed during at least one of the first and second non-illumination intervals; whereby the laser emits light during the first and second illumination intervals at different wavelengths due to the different operating temperatures established during the first and second non-illumination intervals.
Claim 27
Dependent Claim
42 words
The method of claim 23 wherein the first and second pulse currents have respective magnitudes and the first and second illumination intervals have respective durations such that total energy emitted by the laser is identical for the first and second illumination intervals.
Claim 28
Dependent Claim
18 words
The method of claim 23 wherein the first pulse current is substantially constant during the first illumination interval.
Claim 29
Dependent Claim
15 words
The method of claim 23 wherein the sequences occur without intervening time intervals between sequences.
Claim 30
Dependent Claim
68 words
The method of claim 23 wherein said step of establishing different first and second operating temperatures comprises the substeps of: passing first and second bias currents through the laser during respective first and second non-illumination intervals; the first and second bias currents being below threshold and being sufficiently different so as to establish at least a significant portion of the difference between the first and second operating temperatures.
Claim 31
Dependent Claim
24 words
The method of claim 27 wherein the first and second bias currents differ sufficiently that the operating temperatures differ by at least 15° C.
Claim 32
Dependent Claim
41 words
The method of claim 23 wherein said step of establishing different first and second operating temperatures comprises the substep of: transferring heat from a source outside the laser into the laser during only one of the first and second non-illumination intervals.
Claim 33
Dependent Claim
14 words
The improvement of claim 23 wherein the wavelengths differ by at least 30 angstroms.
Claim 34
Dependent Claim
16 words
The improvement of claim 23 wherein the first pulse current decreases during the first illumination interval.
Claim 35
Dependent Claim
22 words
The improvement of claim 23 wherein the first pulse current comprises a plurality of spaced pulses occurring during the first illumination interval.
Claim 36
Independent Claim
126 words
A method of operating a diode laser comprising the steps of: establishing a series of sequences, each sequence including a first non-illumination interval, a first illumination interval, a second non-illumination interval, and a second illumination interval; and for each sequence of the series, passing first bias, first pulse, second bias, and second pulse currents through the laser during respective first non-illumination, first illumination, second non-illumination, and second illumination intervals; the first and second bias currents being below threshold and being sufficiently different so as to establish different operating temperatures for the first and second illumination intervals; the first and second pulse currents being above threshold; whereby the laser emits light during the first and second illumination intervals at different wavelengths due to the different operating temperatures.
Claim 37
Independent Claim
126 words
A method of operating a diode laser comprising the steps of: establishing a series of sequences, each sequence including a first non-illumination interval, a first illumination interval, a second non-illumination interval, and a second illumination interval; and for each sequence of the series, passing first bias, first pulse, second bias, and second pulse currents through the laser during respective first non-illumination, first illumination, second non-illumination, and second illumination intervals; the first and second bias currents being below threshold and being sufficiently different so as to establish different operating temperatures for the first and second illumination intervals; the first and second pulse currents being above threshold; whereby the laser emits light during the first and second illumination intervals at different wavelengths due to the different operating temperatures.
Claim 38
Dependent Claim
42 words
The method of claim 33 wherein the first and second pulse currents have respective magnitudes and the first and second illumination intervals have respective durations such that total energy emitted by the laser is identical for the first and second illumination intervals.
Claim 39
Dependent Claim
18 words
The improvement of claim 33 wherein the first pulse current is substantially constant during the first illumination interval.
Claim 40
Dependent Claim
16 words
The method of claim 33 wherein the sequences occur without intervening time intervals between the sequences.
Claim 41
Dependent Claim
24 words
The method of claim 33 wherein the first and second bias currents differ sufficiently that the operating temperatures differ by at least 15° C.
Claim 42
Dependent Claim
14 words
The improvement of claim 33 wherein the wavelengths differ by at least 30 angstroms.
Claim 43
Dependent Claim
16 words
The improvement of claim 33 wherein the first pulse current decreases during the first illumination interval.
Claim 44
Dependent Claim
22 words
The improvement of claim 33 wherein the first pulse current comprises a plurality of spaced pulses occurring during the first illumination interval.
References Cited (Backward Citations)
US4281904A
Cited
US4369457A
Cited
US4396252A
Cited
US4450459A
Cited
JPS59204292A
Cited
US4514739A
Cited
US4679057A
Cited
US4701607A
Cited
US4940314A
Cited
US4815058A
Cited
US4673953A
Cited
US4918681A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-08-11 | 1996-02-10 | 1996-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-08-11 | 2000-02-10 | 2000-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-08-11 | 2004-02-10 | 2004-08-11 | $7700.00 | Window Closed / Lapsed |