US5059780A
Expired / Lapsed
US
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Light power control circuit for a semiconductor light-emitting element
Assignee: Pioneer Corp
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Filing: 1990-06-19
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Granted: 1991-10-22
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Expires: 2010-06-19
Abstract
Abstract A light power control circuit by which a stable writing without any influence of a high-frequency current on writing data is enabled by performing superposition of the high-frequency signal on a drive current of a laser diode only during a reading mode, and by inhibiting the superposition of the high-frequency current during a writing mode. In a further embodiment having a construction in which a writing drive current is superposed on a reading drive signal in the form of pulses and a voltage proportional to a writing power is subtracted from an error signal in a servo system, an influences of a writing data component on the operation of the servo system is eliminated by effecting a level shift to the voltage by a predetermined level and subtracting the voltage after the level shift from the error signal.
Inventors
- 👤 Yoshiyuki Kakuta
- 👤 Masatoshi Adachi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:58
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/125; G11B7/126; G11B19/00; G11B19/02; G11B7/004; G11B7/0045; G11B7/005; G11B7/08; G11B7/09; G11B7/094; H; H01; H01S; H01S5/00; H01S5/06; H01S5/068; H01S5/0683; H01S5/06835
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
217 words
A light power control circuit for controlling a light power of a semiconductor light-emitting element in an optical disk information recording and reproducing system, comprising: drive current supply means for supplying a drive current to said semiconductor light-emitting element; superposing means for superposing a high-frequency signal on said drive current, wherein said superposing means inhibits the superposition of said high-frequency signal during a writing mode of said recording and reproducing system, wherein said drive current supply means comprises: light sensing device for receiving a part of light rays emitted by said semiconductor light-emitting element; means for supplying a reading drive current corresponding to a reading power set value to said semiconductor light emitting element; means for performing an increase-decrease control of said reading drive current in response to a variation of a detection output signal of said light sensing device with respect to said reading power set value; correction means for correcting said detection output signal of said light sensing device during said writing mode; first modulating means for modulating a voltage corresponding to a writing power set value by writing data; and means for superposing an output current of said first modulating means on said reading drive current and supplying a current obtained by the superposition to said semiconductor light-emitting element as a writing drive current.
Claim 2
Dependent Claim
217 words
A light power control circuit for controlling a light power of a semiconductor light-emitting element in an optical disk information recording and reproducing system, comprising: drive current supply means for supplying a drive current to said semiconductor light-emitting element; superposing means for superposing a high-frequency signal on said drive current, wherein said superposing means inhibits the superposition of said high-frequency signal during a writing mode of said recording and reproducing system, wherein said drive current supply means comprises: light sensing device for receiving a part of light rays emitted by said semiconductor light-emitting element; means for supplying a reading drive current corresponding to a reading power set value to said semiconductor light emitting element; means for performing an increase-decrease control of said reading drive current in response to a variation of a detection output signal of said light sensing device with respect to said reading power set value; correction means for correcting said detection output signal of said light sensing device during said writing mode; first modulating means for modulating a voltage corresponding to a writing power set value by writing data; and means for superposing an output current of said first modulating means on said reading drive current and supplying a current obtained by the superposition to said semiconductor light-emitting element as a writing drive current.
Claim 3
Dependent Claim
83 words
The light power control circuit of claim 1, wherein said drive current supply means further comprises: first averaging means for averaging said detection output signal of said light sensing device; second modulating means for modulating said voltage corresponding to said writing power set value by said writing data; second averaging means for averaging a modulation output signal of said second modulating means; and means for subtracting an output signal of said second averaging means from an output signal of said first averaging means.
Claim 4
Dependent Claim
62 words
The light power control circuit of claim 2, wherein said correction means further comprises: third modulating means for modulating a predetermined correction voltage by said writing data; third averaging means for averaging a modulation output signal of said third modulating means; and means for adding an output signal of said third averaging means on said output signal of said first averaging means.
Claim 5
Dependent Claim
188 words
A light power control circuit for a semiconductor light-emitting element, including a light sensing device for receiving a part of light rays emitted from the semiconductor light-emitting element and structured to control a light power of the semiconductor light-emitting element on the basis of a detection output signal of the light sensing device, said control circuit comprising: control means for supplying a reading drive current corresponding to a reading power set value to said semiconductor light-emitting element; means for performing an increase-decrease control of said reading drive current in response to a variation of a detection output signal of said light sensing device with respect to the reading power set value; first modulating means for modulating a voltage corresponding to a writing power set value by writing data; means for superposing an output current of said first modulating means on said reading drive current and supplying a superposed current to said semiconductor light-emitting element; high frequency current superposing means for superposing a high frequency current on said reading drive current only during a reading mode; and correcting means for correcting said writing drive current during a writing mode.
Claim 6
Dependent Claim
188 words
A light power control circuit for a semiconductor light-emitting element, including a light sensing device for receiving a part of light rays emitted from the semiconductor light-emitting element and structured to control a light power of the semiconductor light-emitting element on the basis of a detection output signal of the light sensing device, said control circuit comprising: control means for supplying a reading drive current corresponding to a reading power set value to said semiconductor light-emitting element; means for performing an increase-decrease control of said reading drive current in response to a variation of a detection output signal of said light sensing device with respect to the reading power set value; first modulating means for modulating a voltage corresponding to a writing power set value by writing data; means for superposing an output current of said first modulating means on said reading drive current and supplying a superposed current to said semiconductor light-emitting element; high frequency current superposing means for superposing a high frequency current on said reading drive current only during a reading mode; and correcting means for correcting said writing drive current during a writing mode.
Claim 7
Dependent Claim
115 words
The light power control circuit of claim 4, wherein said control means comprises: first averaging means for averaging said detection output signal of said light sensing device; second modulating means for modulating said voltage corresponding to said writing power set value by said writing data; second averaging means for averaging a modulation output signal of said second modulating means; and subtracting means for subtracting an output signal of said second averaging means from an output signal of said first averaging means, wherein said control means performs the increase-decrease control of the reading drive current in response to a variation of an output signal of said subtracting means with respect to said reading power set value.
Claim 8
Dependent Claim
26 words
The light power control circuit of claim 4, further comprising means for correcting a detection output signal of said light sensing device during said writing mode.
Claim 9
Dependent Claim
248 words
A light power control circuit for a semiconductor light-emitting element including a light sensing device for sensing a part of light rays emitted from the semiconductor light-emitting element, and structured to control a light power of the semiconductor light-emitting element on the basis of a detection output signal of the light sensing device, the circuit comprising: means for supplying a reading drive current signal corresponding to a reading power set value to said semiconductor light-emitting element; first modulating means for modulating a current corresponding to a writing power set value by writing data; means for superposing an output current of said first modulating means on said reading drive current and supplying a current obtained by the superposition to said semiconductor light-emitting element as a writing drive current; first averaging means for averaging said detection output signal of the light sensing means; level shifting means for shifting a signal level corresponding to said writing power set value by a predetermined level; second modulating means for modulating an output signal of said level shifting means by said writing data; second averaging means for averaging a modulation output signal of the second modulating means; subtracting means for subtracting an output signal of the second averaging means from an output signal of the first averaging means; and means for performing an increasing and decreasing control of the reading drive current in response to a variation of an output subtraction signal of said subtracting means with respect to said reading power set value.
Claim 10
Dependent Claim
248 words
A light power control circuit for a semiconductor light-emitting element including a light sensing device for sensing a part of light rays emitted from the semiconductor light-emitting element, and structured to control a light power of the semiconductor light-emitting element on the basis of a detection output signal of the light sensing device, the circuit comprising: means for supplying a reading drive current signal corresponding to a reading power set value to said semiconductor light-emitting element; first modulating means for modulating a current corresponding to a writing power set value by writing data; means for superposing an output current of said first modulating means on said reading drive current and supplying a current obtained by the superposition to said semiconductor light-emitting element as a writing drive current; first averaging means for averaging said detection output signal of the light sensing means; level shifting means for shifting a signal level corresponding to said writing power set value by a predetermined level; second modulating means for modulating an output signal of said level shifting means by said writing data; second averaging means for averaging a modulation output signal of the second modulating means; subtracting means for subtracting an output signal of the second averaging means from an output signal of the first averaging means; and means for performing an increasing and decreasing control of the reading drive current in response to a variation of an output subtraction signal of said subtracting means with respect to said reading power set value.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-10-21 | 1995-04-22 | 1995-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-10-21 | 1999-04-22 | 1999-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-10-21 | 2003-04-22 | 2003-10-22 | $7700.00 | Window Closed / Lapsed |