US5398227A
Expired / Lapsed
US
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Magnetooptical recording reproducing apparatus and method for determining the power of an irradiating light beam on the basis of a detected amplitude of a recording signal
Assignee: Canon Inc
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Filing: 1993-03-01
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Granted: 1995-03-14
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Expires: 2013-03-01
Abstract
Abstract A magnetooptical recording/reproducing apparatus is provided with a device for determinating a power of a light beam which is emitted from a light source. In the apparatus, the light beam is irradiated on a magnetooptical recording medium while a magnetic field modulated according to a recording signal is applied to a portion on which the light beam is being irradiated. Light reflected from the medium upon the irradiation of the light beam thereto is detected by a detector, the output from which is used to reproduce the recording signal. The amplitude of the recording signal is detected from the reproduction signal. The power of the light beam to be emitted from the light source is determined on the basis of the detected amplitude of the recording signal.
Inventors
- 👤 Yasuyuki Miyaoka
- 👤 Koyo Hasegawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 02:29
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10595; G11B11/10502; G11B11/10504; G11B11/10508
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
112 words
A magnetooptical recording/reproducing apparatus comprising: means for irradiating a magnetooptical recording medium with a light beam; means for applying a magnetic field, modulated in accordance with a signal to be recorded, to a portion of the medium, irradiated by the light beam, to record a signal on the medium; detecting means for detecting a light beam from the recording medium and for producing a detection output; reading means for reading out from the output of said detecting means a magnetooptical signal during a recording operation; and determining means for determining the power of the light beam on the basis of an amplitude of the magnetooptical signal read out by said reading means.
Claim 2
Dependent Claim
112 words
A magnetooptical recording/reproducing apparatus comprising: means for irradiating a magnetooptical recording medium with a light beam; means for applying a magnetic field, modulated in accordance with a signal to be recorded, to a portion of the medium, irradiated by the light beam, to record a signal on the medium; detecting means for detecting a light beam from the recording medium and for producing a detection output; reading means for reading out from the output of said detecting means a magnetooptical signal during a recording operation; and determining means for determining the power of the light beam on the basis of an amplitude of the magnetooptical signal read out by said reading means.
Claim 3
Dependent Claim
33 words
An apparatus according to claim 1, wherein said determining means comprises means for controlling the power of the light beam such that the amplitude of the magnetooptical signal is within a predetermined range.
Claim 4
Dependent Claim
29 words
An apparatus according to claim 1, further comprising a temperature sensor for detecting the temperature in the apparatus and for sending a temperature detection signal to said determining means.
Claim 5
Dependent Claim
22 words
An apparatus according to claim 1, further comprising means for filtering the signal sent from said reading means to said determining means.
Claim 6
Dependent Claim
47 words
An apparatus according to claim 1, wherein the magnetooptical recording medium includes a first magnetic layer, and a second magnetic layer having a higher coercive force and a lower Curie temperature than those of the first magnetic layer and being exchange coupled with the first magnetic layer.
Claim 7
Dependent Claim
130 words
A magnetooptical recording/reproducing apparatus comprising: a light source for emitting a light beam; an optical system for irradiating a magnetooptical recording medium with the light beam emitted from said light source; a magnetic head for recording information signals on the recording medium by applying a magnetic field, modulated in accordance with a signal to be recorded, to a portion of the recording medium, irradiated by the light beam; a photodetector for detecting light, reflected by the medium, and for producing an output; a signal processing circuit for reading out from the output of said photodetector a magnetooptical signal during a recording operation; and a controller for determining the power of the light beam on the basis of an amplitude of the magnetooptical signal read out by said signal processing circuit.
Claim 8
Dependent Claim
130 words
A magnetooptical recording/reproducing apparatus comprising: a light source for emitting a light beam; an optical system for irradiating a magnetooptical recording medium with the light beam emitted from said light source; a magnetic head for recording information signals on the recording medium by applying a magnetic field, modulated in accordance with a signal to be recorded, to a portion of the recording medium, irradiated by the light beam; a photodetector for detecting light, reflected by the medium, and for producing an output; a signal processing circuit for reading out from the output of said photodetector a magnetooptical signal during a recording operation; and a controller for determining the power of the light beam on the basis of an amplitude of the magnetooptical signal read out by said signal processing circuit.
Claim 9
Dependent Claim
29 words
An apparatus according to claim 6, wherein said controller controls the power of the light beam such that the amplitude of the magnetooptical signal is within a predetermined range.
Claim 10
Dependent Claim
28 words
An apparatus according to claim 6, further comprising a temperature sensor for detecting the temperature in the apparatus and for sending a temperature detection signal to said controller.
Claim 11
Dependent Claim
47 words
An apparatus according to claim 6, wherein the magnetooptical recording medium includes a first magnetic layer, and a second magnetic layer having a higher coercive force and a lower Curie temperature than those of the first magnetic layer and being exchange coupled with the first magnetic layer.
Claim 12
Dependent Claim
24 words
An apparatus according to claim 6, further comprising a filter circuit for filtering the signal sent from said signal processing circuit to said controller.
Claim 13
Independent Claim
145 words
A method for determining the power of a light beam in a magnetooptical recording/reproducing apparatus for effecting at least one of information recording and reproduction by irradiating a magnetooptical recording medium with a light beam, said method comprising the steps of: irradiating the medium with a light beam having a constant power; applying, simultaneously with the irradiation of the medium with the light beam, a magnetic field, modulated in accordance with a signal to be recorded, to a portion of the medium, irradiated with the light beam to record a signal on the medium; detecting, simultaneously with said irradiation of the light beam, light reflected by the medium; reading out a magnetooptical signal from the reflected light detected in said detecting step; and determining the power of the light beam so that an amplitude of the read out magnetooptical signal falls within a predetermined range.
Claim 14
Independent Claim
145 words
A method for determining the power of a light beam in a magnetooptical recording/reproducing apparatus for effecting at least one of information recording and reproduction by irradiating a magnetooptical recording medium with a light beam, said method comprising the steps of: irradiating the medium with a light beam having a constant power; applying, simultaneously with the irradiation of the medium with the light beam, a magnetic field, modulated in accordance with a signal to be recorded, to a portion of the medium, irradiated with the light beam to record a signal on the medium; detecting, simultaneously with said irradiation of the light beam, light reflected by the medium; reading out a magnetooptical signal from the reflected light detected in said detecting step; and determining the power of the light beam so that an amplitude of the read out magnetooptical signal falls within a predetermined range.
Claim 15
Dependent Claim
24 words
A method according to claim 11, wherein the recording signal includes a signal for recording pits of a predetermined test pattern on the medium.
Claim 16
Dependent Claim
41 words
A method according to claim 11, further comprising a step, prior to said step of irradiating the medium with the light beam, for erasing a signal previously recorded in an area of the medium to be irradiated by the light beam.
Claim 17
Dependent Claim
47 words
A method according to claim 11, wherein the magnetooptical recording medium includes a first magnetic layer, and a second magnetic layer having a higher coercive force and a lower Curie temperature than those of the first magnetic layer and being exchange coupled with the first magnetic layer.
Claim 18
Independent Claim
151 words
A method for determining the power of a light beam, in a magnetooptical recording/reproducing apparatus for effecting at least one of information recording and reproduction by irradiating a magnetooptical recording medium with the light beam, said method comprising the steps of: recording pits having a predetermined pattern on the medium; irradiating a portion of the medium on which the pits are recorded with a light beam having a constant power; applying, simultaneously with the irradiation of the medium with the light beam, a magnetic field having a constant direction to a portion of the medium, irradiated with the light beam to record a signal on the medium; detecting, simultaneously with the irradiation of the medium with the light beam, light reflected by the medium; reproducing a signal of the pits from the detected reflected light; and determining the power of the light beam, based on an amplitude of the reproduced signal.
Claim 19
Independent Claim
151 words
A method for determining the power of a light beam, in a magnetooptical recording/reproducing apparatus for effecting at least one of information recording and reproduction by irradiating a magnetooptical recording medium with the light beam, said method comprising the steps of: recording pits having a predetermined pattern on the medium; irradiating a portion of the medium on which the pits are recorded with a light beam having a constant power; applying, simultaneously with the irradiation of the medium with the light beam, a magnetic field having a constant direction to a portion of the medium, irradiated with the light beam to record a signal on the medium; detecting, simultaneously with the irradiation of the medium with the light beam, light reflected by the medium; reproducing a signal of the pits from the detected reflected light; and determining the power of the light beam, based on an amplitude of the reproduced signal.
Claim 20
Dependent Claim
18 words
A method according to claim 15, wherein the pits are recorded in a predetermined area of the medium.
Claim 21
Dependent Claim
47 words
A method according to claim 15, wherein the magnetooptical recording medium includes a first magnetic layer, and a second magnetic layer having a higher coercive force and a lower Curie temperature than those of the first magnetic layer and being exchange coupled with the first magnetic layer.
Claim 22
Independent Claim
208 words
A method for determining the power of a light beam, in a magnetooptical recording/reproducing apparatus for effecting at least one of information recording and reproduction by irradiating a magnetooptical recording medium with the light beam, said method comprising the steps of: irradiating the medium with a light beam having a constant power; applying, simultaneously with the irradiation of the medium with the light beam, a magnetic field, modulated in accordance with a signal to be recorded, to a portion of the medium, irradiated by the light beam, thereby recording a first signal on the medium; re-irradiating the portion of the medium on which the first signal is recorded with a light beam having a constant power; applying, simultaneously with the re-irradiation of the light beam, a magnetic field, modulated in accordance with a second signal to be recorded, to a portion of the medium, irradiated with the light beam, thereby overwriting the second signal on the portion of the medium on which the first signal has been recorded; detecting, simultaneously with the re-irradiation of the light beam, light reflected by the medium; reproducing the first signal from the detected reflected light; and determining the power of the light beam, based on an amplitude of the reproduced first signal.
Claim 23
Independent Claim
208 words
A method for determining the power of a light beam, in a magnetooptical recording/reproducing apparatus for effecting at least one of information recording and reproduction by irradiating a magnetooptical recording medium with the light beam, said method comprising the steps of: irradiating the medium with a light beam having a constant power; applying, simultaneously with the irradiation of the medium with the light beam, a magnetic field, modulated in accordance with a signal to be recorded, to a portion of the medium, irradiated by the light beam, thereby recording a first signal on the medium; re-irradiating the portion of the medium on which the first signal is recorded with a light beam having a constant power; applying, simultaneously with the re-irradiation of the light beam, a magnetic field, modulated in accordance with a second signal to be recorded, to a portion of the medium, irradiated with the light beam, thereby overwriting the second signal on the portion of the medium on which the first signal has been recorded; detecting, simultaneously with the re-irradiation of the light beam, light reflected by the medium; reproducing the first signal from the detected reflected light; and determining the power of the light beam, based on an amplitude of the reproduced first signal.
Claim 24
Dependent Claim
32 words
A method according to claim 18, wherein said reproducing step comprises filtering the detection signal obtained from the reflected light, thereby extracting a component of the first signal from the detection signal.
Claim 25
Dependent Claim
20 words
A method according to claim 18, wherein the second signal has a frequency different from that of the first signal.
Claim 26
Dependent Claim
17 words
A method according to claim 18, wherein the second signal is different in phase the first signal.
Claim 27
Dependent Claim
47 words
A method according to claim 18, wherein the magnetooptical recording medium includes a first magnetic layer, and a second magnetic layer having a higher coercive force and a lower Curie temperature than those of the first magnetic layer and being exchange coupled with the first magnetic layer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-03-13 | 1998-09-12 | 1999-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-03-13 | 2002-09-12 | 2003-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-03-13 | 2006-09-12 | 2007-03-14 | $7700.00 | Window Closed / Lapsed |