US4970707A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical tape apparatus with a tracking control mechanism and/or a focusing control mechanism
Assignee: Hitachi Ltd
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Filing: 1988-09-01
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Granted: 1990-11-13
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Expires: 2008-09-01
Abstract
Abstract An optical tape apparatus having improved focus and tracking control. An optical head records, reproduces, or rewrites data on an optical tape by helically scanning the tape with a laser beam. A guide plate is disposed between the optical head and the tape to prevent the beam from becoming unfocused due to fluctuation of the tape cuased by an air film between the optical head and the tape. The optical head contains a semiconductor laser and an optical system exhibiting chromatic aberration for directing the laser beam onto the tape. The optical system includes a condenser lens for focusing the beam onto the tape. Fine focus control is achieved by changing the wavelength of the laser beam by directing part of the beam reflected from the tape back to the laser, thereby changing the focal point of the beam by virtue of the chromatic aberration of the optical system. Coarse focus control is achieved by mounting the condenser lens on a piezoelectric actuator which moves the consenser lens to focus the beam onto the tape. A recording head for recording timing marks and tracking signals on the tape is disposed in advance of the optical head. A reading head reads the timing marks and the optical head reads the tracking signals. The timing marks and tracking signals are used to control the operation of the apparatus such that the tape is transported with a constant speed and data on diagonal signal tracks on the tape is accurately recorded, reproduced, or rewritten.
Inventors
- 👤 Fumio Hara
- 👤 Yoshito Tsunoda
- 👤 Shigeru Nakamura
- 👤 Yoshizumi Eto
- 👤 Seiichi Mita
- 👤 Morishi Izumita
- 👤 Hiroyuki Tsuchinaga
- 👤 Masuo Kasai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:45
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/002; G11B7/003; G11B7/0031; G11B7/0925
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
124 words
An optical tape apparatus comprising: transporting means for transporting an optical tape comprising an optical recording medium; an optical head for recording, reproducing, or rewriting data on the tape by directing an optical beam onto the tape while the tape is being transported by the transporting means and scanning the beam across the tape at a predetermined angle with respect to a longitudinal dimension of the tape; and a recording head disposed in advance of the optical head with respect to a direction in which the tape is transported by the transporting means for recording control data on the tape, wherein the control data is to be used in controlling the operation of at least one of the transporting means and the optical head.
Claim 2
Dependent Claim
124 words
An optical tape apparatus comprising: transporting means for transporting an optical tape comprising an optical recording medium; an optical head for recording, reproducing, or rewriting data on the tape by directing an optical beam onto the tape while the tape is being transported by the transporting means and scanning the beam across the tape at a predetermined angle with respect to a longitudinal dimension of the tape; and a recording head disposed in advance of the optical head with respect to a direction in which the tape is transported by the transporting means for recording control data on the tape, wherein the control data is to be used in controlling the operation of at least one of the transporting means and the optical head.
Claim 3
Dependent Claim
22 words
An optical tape apparatus according to claim 1, wherein the recording head records the control data at dispersed locations on the tape.
Claim 4
Dependent Claim
49 words
An optical tape apparatus according to claim 2, wherein the optical head scans the beam across the tape along signal tracks on the tape which are oriented at the predetermined angle, and wherein at least some of the control data is alternately recorded on different sides of the tracks.
Claim 5
Dependent Claim
42 words
An optical tape apparatus according to claim 1, wherein the recording head contacts the tape and is rotated by the tape as the tape is being transported by the transporting means at the same speed at which the tape is being transported.
Claim 6
Dependent Claim
51 words
An optical tape apparatus according to claim 1, wherein the control data comprises timing marks to be used in detecting the speed at which the tape is being transported by the transporting means, and wherein the recording head records the timing marks at predetermined intervals along an edge of the tape.
Claim 7
Dependent Claim
49 words
An optical tape apparatus according to claim 5, further comprising a reading head for detecting the timing marks, wherein the optical head records address signals on the tape at places where data is to be recorded before recording the data in accordance with an output of the reading head.
Claim 8
Dependent Claim
46 words
An optical tape apparatus according to claim 5, further comprising: a reading head for detecting the timing marks; and means for controlling the transporting means in accordance with an output of the reading head such that the transporting means transports the tape at a constant speed.
Claim 9
Dependent Claim
118 words
An optical tape apparatus comprising: means for transporting in a longitudinal direction an optical tape comprising an optical recording medium on which control data comprising tracking signals is recorded at dispersed locations in the longitudinal direction; and an optical head for recording, reproducing, or rewriting data on the tape and detecting the tracking signals recorded on the tape by directing an optical beam onto the tape while the tape is being transported by the transporting means and scanning the beam across the tape at a predetermined angle with respect to the longitudinal direction; wherein the optical head includes a tracking mechanism for controlling the position of the beam on the tape in accordance with the detected tracking signals.
Claim 10
Dependent Claim
118 words
An optical tape apparatus comprising: means for transporting in a longitudinal direction an optical tape comprising an optical recording medium on which control data comprising tracking signals is recorded at dispersed locations in the longitudinal direction; and an optical head for recording, reproducing, or rewriting data on the tape and detecting the tracking signals recorded on the tape by directing an optical beam onto the tape while the tape is being transported by the transporting means and scanning the beam across the tape at a predetermined angle with respect to the longitudinal direction; wherein the optical head includes a tracking mechanism for controlling the position of the beam on the tape in accordance with the detected tracking signals.
Claim 11
Dependent Claim
55 words
An optical tape apparatus according to claim 8, wherein the control data further comprises timing marks, and further comprising: a reading head for detecting the timing marks; and means for controlling the transporting means in accordance with an output of the reading head such that the transporting means transports the tape at a constant speed.
Claim 12
Dependent Claim
165 words
An optical tape apparatus comprising: means for transporting an optical tape comprising an optical recording medium in a longitudinal direction; and an optical head for recording, reproducing, or rewriting data on the tape by directing an optical beam onto the tape while the tape is being transported by the transporting means and scanning the beam across the tape at a predetermined angle with respect to the longitudinal direction; wherein the optical head comprises: a semiconductor laser for emitting an optical beam; and an optical system exhibiting chromatic aberration for directing the beam emitted by the laser onto the tape; wherein the beam is reflected from the tape after being directed onto the tape, and wherein the optical system focuses the directed beam onto the tape by changing the wavelength of the beam emitted by the laser by directing part of the reflected beam back to the laser, thereby changing the focal point of the beam by virtue of the chromatic aberration of the optical system.
Claim 13
Dependent Claim
165 words
An optical tape apparatus comprising: means for transporting an optical tape comprising an optical recording medium in a longitudinal direction; and an optical head for recording, reproducing, or rewriting data on the tape by directing an optical beam onto the tape while the tape is being transported by the transporting means and scanning the beam across the tape at a predetermined angle with respect to the longitudinal direction; wherein the optical head comprises: a semiconductor laser for emitting an optical beam; and an optical system exhibiting chromatic aberration for directing the beam emitted by the laser onto the tape; wherein the beam is reflected from the tape after being directed onto the tape, and wherein the optical system focuses the directed beam onto the tape by changing the wavelength of the beam emitted by the laser by directing part of the reflected beam back to the laser, thereby changing the focal point of the beam by virtue of the chromatic aberration of the optical system.
Claim 14
Dependent Claim
27 words
An optical tape apparatus according to claim 10, wherein the optical system comprises a collimator lens exhibiting chromatic aberration for collimating the beam emitted by the laser.
Claim 15
Dependent Claim
34 words
An optical tape apparatus according to claim 11, further comprising a rotatable drum in which the optical head is disposed, wherein the collimator lens is disposed near the center of rotation of the drum.
Claim 16
Dependent Claim
30 words
An optical tape apparatus according to claim 10, wherein the optical system comprises a condenser lens exhibiting chromatic aberration for focusing the beam emitted by the laser onto the tape.
Claim 17
Dependent Claim
51 words
An optical tape apparatus according to claim 10, further comprising a guide plate disposed between the tape and the optical head for stabilizing the tape while it is being transported by the transporting means so as to eliminate fluctuations in the position of the tape with respect to the optical head.
Claim 18
Dependent Claim
37 words
An optical tape apparatus according to claim 14, wherein the optical head is rotatable, and wherein the guide plate has an arcuate or circular shape which is concentric with the center of rotation of the optical head.
Claim 19
Dependent Claim
29 words
An optical tape apparatus according to claim 14, wherein the guide plate is made of a transparent material having a very smooth surface such as glass or plastic resin.
Claim 20
Dependent Claim
19 words
An optical tape apparatus according to claim 14, wherein the guide plate is from 1 to 2 mm thick.
Claim 21
Dependent Claim
77 words
An optical tape apparatus according to claim 10, further comprising a drum in which the optical head is rotatably disposed and on which the tape is wound while being transported by the transporting means, wherein the drum is provided with a slit at a portion of the drum on which the tape is wound and comprises a guide plate disposed at the slit for stabilizing the tape while the tape is being transported by the transporting means.
Claim 22
Dependent Claim
33 words
An optical tape apparatus according to claim 18, wherein the guide plate projects from the surface of the drum and contacts the tape while the tape is being transported by the transporting means.
Claim 23
Dependent Claim
36 words
An optical tape apparatus according to claim 18, wherein the guide plate is a condenser lens which is part of the optical system and is for focusing the beam emitted by the laser onto the tape.
Claim 24
Dependent Claim
54 words
An optical tape apparatus according to claim 10, further comprising a drum in which the optical head is rotatably mounted and on which the tape is wound while being transported by the transporting means, wherein the drum is made of a transparent material having a very smooth surface such as glass or plastic resin.
Claim 25
Dependent Claim
49 words
An optical tape apparatus according to claim 10, wherein the optical system comprises: a condenser lens for focusing the beam emitted by the laser onto the tape; and a piezoelectric actuator for supporting the condenser lens and for focusing the beam onto the tape by moving the condenser lens.
Claim 26
Dependent Claim
81 words
An optical tape apparatus according to claim 22, wherein the optical head is rotatable, and wherein the piezoelectric actuator supports the condenser lens at a position while the optical head is not rotating which is displaced from a desired position of the condenser lens while the optical head is rotating such that when the optical head is rotating, a centrifugal force acting on the condenser lens displaces the condenser lens to the desired position against resistance provided by the piezoelectric actuator.
Claim 27
Dependent Claim
58 words
An optical tape apparatus according to claim 10, further comprising: a second optical head of the type recited in claim 10; and a rotatable drum in which the two optical heads are disposed symmetrically with respect to the center of rotation of the drum and on which the tape is wound while being transported by the transporting means.
Claim 28
Dependent Claim
67 words
An optical tape apparatus according to claim 10, further comprising a recording head disposed in advance of the optical head with respect to the longitudinal direction in which the tape is transported by the transported means for recording control data on the tape, wherein the control data is to be used in controlling the operation of at least one of the transporting means and the optical head.
Claim 29
Dependent Claim
79 words
An optical tape apparatus according to claim 25, wherein the control data comprises timing marks recorded at dispersed locations on the tape to be used in detecting the speed at which the tape is being transported by the transporting means, and further comprising: a reading head for detecting the timing marks; and means for controlling the transporting means in accordance with an output of the reading means such that the transporting means transports the tape at a constant speed.
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) | 1993-11-12 | 1994-05-14 | 1994-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-11-12 | 1998-05-14 | 1998-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-11-12 | 2002-05-14 | 2002-11-13 | $7700.00 | Window Closed / Lapsed |