Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
1999-08-05
2001-08-28
Huber, Paul W. (Department: 2651)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S053120, C369S044270
Reexamination Certificate
active
06282161
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Application No. 98-31871, filed Aug. 5, 1998, in the Korean Patent Office, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical recording and reproducing apparatus and a tilt adjusting method, and more particularly, to an optical recording and reproducing apparatus for adjusting a tilt of an optical pickup in accordance with the amount of jitter of a reproducing signal, a tilt adjusting method therefor, and a recording control method therefor.
2. Description of the Related Art
An optical pickup of an optical recording and reproducing apparatus requires an actuator which is an object lens driver. The actuator may precisely move the object lens to a desired position in response to a magnetic field generated by a permanent magnet.
However, when an optical disk is curved while the optical recording and reproducing apparatus records and reads information on or from the disk, or when there is a tilt in an optical pickup during assembly of the optical recording and reproducing apparatus, the optical signal deteriorates. In order to compensate for the deterioration of the optical signal, the relative tilt amount between the disk and the object lens must be measured to remove the measured tilt amount.
FIG. 1
shows the structure of a conventional tilt adjusting apparatus. The apparatus of
FIG. 1
includes a tilt detector for applying an optical signal to the disk and detecting the tilt amount by the optical signal reflected from the disk and a tilt motor (not shown) which adjusts the tilt of the optical pickup in accordance with the detected tilt amount.
The tilt detector includes a light emitting device
12
fixed on the optical pickup
10
and light receiving devices
14
a
and
14
b
to detect the tilt amount between the optical axis and the disk. The signals detected from the light receiving devices
14
a
and
14
b
become input signals for driving a tilt motor through a differential amplifier (not shown).
The tilt motor drives the optical pickup
10
to remove the tilt amount and thus to suppress deterioration of the optical signal. The optical pickup
10
pivots around a fixing and supporting axis
18
. The tilt motor moves one side of the optical pickup
10
upward or downward around the fixing and supporting axis
18
.
However, in the conventional tilt adjusting apparatus of
FIG. 1
, the tilt detector is arranged on the upper surface of the optical pickup to apply an optical signal to the disk or the size is relatively large, which defined a space.
The tilt detector cannot be arranged in the same position as the objective lens, so that the tilt amount of a current reproduction position cannot be precisely detected.
An additional adjusting apparatus is required to obtain an initial position when the tilt detector is installed on the upper surface of the optical pickup. Also, the amount of light is changed according to the reflection rate of a disk when light beams emitted from the light emitting device are reflected from the disk, so that the precision of tilt measurement and tilt adjustment is deteriorated in a disk having a low reflection rate.
SUMMARY OF THE INVENTION
To solve the above problems, it is an object of the present invention to provide an apparatus for compensating for deterioration of an optical signal due to a tilt between a disk and an object lens.
It is another object of the present invention to provide a method of adjusting the tilt between the disk and the object lens using the above apparatus.
It is still another object of the present invention to provide a recording control method of optimizing an amount of jitter of a record signal using the apparatus.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
An optical reproducing apparatus to achieve the first and other objects of present invention includes an optical pickup; a tilt adjusting unit for adjusting the tilt angle of the optical pickup; a jitter detecting unit for detecting the amount of jitter of a reproducing signal generated by the optical pickup; and a tilt controlling unit for minimizing the amount of jitter by feeding the amount of jitter detected by the jitter detecting unit back to the tilt adjusting unit.
Here, preferably, the optical recording and reproducing apparatus further comprises a displacement sensor for detecting the tilt angle of the optical pickup with respect to a predetermined reference surface, wherein the tilt controlling unit obtains optimum tilt adjustment values at two points of the optical pickup spaced apart from each other along the radial direction of the disk, and the tilt angle is adjusted by interpolation of the obtained optimum tilt adjustment values.
Here, preferably, the optical recording and reproducing apparatus further comprises a memory for storing the optimum tilt adjustment values obtained from the tilt controlling unit.
It is also preferable that the displacement sensor comprises a light emitting device for generating an optical signal; a reflector for reflecting an optical signal generated from the light emitting device; and a light receiving device for receiving an optical signal reflected from the reflector, and generating an electrical signal corresponding thereto.
Preferably, the reflector is installed on an optical pickup support unit on which the optical pickup is mounted and which is rotatable about an axis fixed relative to an optical pickup fixing frame. The optical pickup fixing frame has the light emitting and receiving device mounted thereon.
To achieve the second and other objects of the present invention, a tilt adjusting method is provided, the tilt adjusting method of an optical recording and reproducing apparatus having an optical pickup including an object lens, a tilt adjusting unit for adjusting the tilt angle of the object lens, a displacement sensor detecting the tilt degree of the optical pickup with respect to a predetermined reference surface, a jitter detecting unit for detecting the amount of jitter of a reproducing signal generated by the optical pickup, and a tilt controlling unit for minimizing the amount of the jitter by feeding the amount of jitter detected by the jitter detecting means back to the tilt adjusting unit, comprises: (a) moving the optical pickup to an inner circumference of a disk when the disk is mounted on the optical pickup apparatus, operating a focus and a tracking servo to adjust an offset of the focus and the track servo such that the jitter of a reproducing signal is minimized, and driving the tilt driving unit to detect a displacement amount value S_inner of the displacement sensor at a point at which the jitter of the reproducing signal is minimized; (b) moving the optical pickup to an outer circumference of the disk, operating the focus and the tracking servo to adjust the offset of the focus and the track servo such that the jitter of the reproducing signal is minimized, and driving the tilt driving unit to detect a displacement amount value S_outer of the displacement sensor at the point in which the jitter of the reproducing signal is minimum; (c) storing the displacement amount values S_inner and S_outer in which the jitter at the inner and outer circumferences, respectively, of the disk are minimized; (d) calculating a tilt control value of a reproducing position by interpolation with reference to the stored displacement amount values S_inner and S_outer during reproduction of the disk; and (e) applying the calculated tilt control value to the tilt driving unit to adjust the tilt of the optical pickup.
A recording control method to achieve the third and other objects of the present invention is provided, the recording control method of an optical recording and reproducing apparatus having an optical pickup including an object lens, a tilt adjus
Hwang In-Wook
Kim Seok-jung
Ryoo Byung-ryul
Seo Joong-eon
Seo Young-sun
Huber Paul W.
Samsung Electronics Co,. Ltd.
Staas & Halsey , LLP
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