US4835754A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tracking control device of an optical pick-up
Assignee: Ricoh Co Ltd
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Filing: 1987-11-19
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Granted: 1989-05-30
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Expires: 2007-11-19
Abstract
Abstract A tracking control system for use in an optical pick-up of an optical disc recording and reproducing apparatus includes a pair of photoelectric elements for receiving light reflecting from an optical disk. A pair of light current outputs obtained from the photoelectric elements is processed to produce a differential signal. A low pass filter is provided as a phase delay compensation circuit for compensating the low frequency component of the differential signal. During a track jump mode, the differential signal is processed through the low pass filter whose output is added with a kick pulse to produce a drive signal for use in a tracking actuator. The input side of the low pass filter may be disconnected during a track jump mode, thereby causing the low pass filter to also serve as a holding circuit for holding the voltage of the differential signal immediately prior to track jump.
Inventors
- 👤 Kazutaka Yamamoto
- 👤 Toshihiro Shigemori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:21
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0941; G11B7/085; G11B7/08505; G11B7/08517; G11B7/0901
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
226 words
A tracking control system for tracking a recording track of an optical disk in an optical disk apparatus, comprising: detecting means for detecting light reflecting from an optical disk, said detecting means including a pair of light-receiving surfaces for producing a pair of light output signals; producing means for producing a differential signal from said pair of light output signals; first compensating means responsive to said differential signal for compensating a first frequency component of said differential signal to produce a first signal; second compensating means responsive to said differential signal for compensating a second frequency component, which is different from said first frequency component, of said differential signal to produce a second signal; zero cross detecting means for detecting a zero cross point of said differential signal to provide a zero cross detection signal; pulse generating means for generating a pulse; summing means for summing said first and second signals and said pulse to provide a drive signal for driving a tracking actuator; a first switch connected between said first compensating means and said summing means; a second switch connected between said second compensating means and said summing means; and controlling means responsive to said zero cross detection signal for controlling said pulse generating means to generate a pulse, said controlling means also controlling an on/off status of each of said first and second switches.
Claim 2
Dependent Claim
226 words
A tracking control system for tracking a recording track of an optical disk in an optical disk apparatus, comprising: detecting means for detecting light reflecting from an optical disk, said detecting means including a pair of light-receiving surfaces for producing a pair of light output signals; producing means for producing a differential signal from said pair of light output signals; first compensating means responsive to said differential signal for compensating a first frequency component of said differential signal to produce a first signal; second compensating means responsive to said differential signal for compensating a second frequency component, which is different from said first frequency component, of said differential signal to produce a second signal; zero cross detecting means for detecting a zero cross point of said differential signal to provide a zero cross detection signal; pulse generating means for generating a pulse; summing means for summing said first and second signals and said pulse to provide a drive signal for driving a tracking actuator; a first switch connected between said first compensating means and said summing means; a second switch connected between said second compensating means and said summing means; and controlling means responsive to said zero cross detection signal for controlling said pulse generating means to generate a pulse, said controlling means also controlling an on/off status of each of said first and second switches.
Claim 3
Dependent Claim
59 words
The system of claim 1 wherein both of said first and second switches are rendered on and said pulse generating means is held inoperative by said controlling means in a normal tracking mode operation and said first switch is rendered off and said second switch is rendered on by said controlling means in a track jump mode of operation.
Claim 4
Dependent Claim
34 words
The system of claim 2 wherein said first frequency component includes intermediate and high frequency components of said differential signal and said second frequency component includes a low frequency component of said differential signal.
Claim 5
Dependent Claim
15 words
The system of claim 3 wherein said second compensating means includes a low pass filter.
Claim 6
Dependent Claim
33 words
The system of claim 2 further comprising a third switch connected between said producing means and said second compensating means, an on/off status of said third switch being controlled by said controlling means.
Claim 7
Dependent Claim
29 words
The system of claim 5 wherein said third switch is rendered on in a normal tracking mode of operation and rendered off in a track jump mode of operation.
Claim 8
Dependent Claim
34 words
The system of claim 6 wherein said first frequency component includes intermediate and high frequency components of said differential signal and said second frequency component includes a low frequency component of said differential signal.
Claim 9
Dependent Claim
31 words
The system of claim 7 wherein said second compensating means includes a low pass filter which also serves as a holding circuit for holding a voltage immediately prior to track jump.
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) | 1992-05-29 | 1992-11-28 | 1993-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-29 | 1996-11-28 | 1997-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-29 | 2000-11-28 | 2001-05-30 | $7700.00 | Window Closed / Lapsed |