Dynamic information storage or retrieval – Information location or remote operator actuated control – Selective addressing of storage medium
Reexamination Certificate
1998-11-18
2001-01-09
Psitos, Aristotelis M. (Department: 2752)
Dynamic information storage or retrieval
Information location or remote operator actuated control
Selective addressing of storage medium
C369S219100, C369S221000
Reexamination Certificate
active
06172949
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to disk recording or playback devices by which information is recorded on or reproduced from disks serving as recording media, and a method of adjusting the initial position of the pickup of the device.
BACKGROUND OF THE INVENTION
FIG. 2
shows a mechanism deck
2
already known for use in such disk recording or playback devices. The deck
2
comprises a chassis
4
formed with an opening
40
, two guide rods
41
,
41
extending across the opening
40
, and a turntable
31
provided at an end portion of the opening
40
for rotating a disk. Mounted on the two guide rods
41
,
41
is a pickup
3
having an object lens
30
and movable toward the turntable
31
. The pickup
3
is driven by a motor (not shown) on the chassis
4
. Provided inside the opening
40
close to the turntable
31
is a sensor switch SW for detecting the pickup
3
as brought closest to the inner periphery of the disk.
The disk
6
is housed in a cartridge
60
, which is provided with a movable shutter
61
. With the cartridge
60
placed on support pins
42
on the chassis
4
, the shutter
61
slidingly moves to expose the lower surface of the disk
6
, whereupon a beam is projected from the lens
30
of the pickup
3
for recording or playback.
With reference to
FIG. 3
, the disk
6
is 64 mm in outside diameter and 29 mm in inside diameter. An inner peripheral region ranging from 29 mm to 32 mm in diameter is referred to as a lead-in area A, a region ranging from 32 mm to 61 mm in diameter as a program area B, and an outer peripheral region ranging from 61 mm to 64 mm in diameter as a lead-out area. Recorded in the lead-in area A is a so-called TOC (table of contents) which is a summary of the information recorded on the disk. For the recognition of the position of the pickup
3
, the lead-in area A invariably needs to have recorded therein signals. The program area B has recorded therein desired information such as music signals. Detection of the lead-out area C by the pickup
3
indicates that the pickup
3
has moved out of the program area B.
The pickup
3
is designed to be positioned in the lead-in area A when in a standby state for recording or playback, pressing the sensor switch SW. This position will be referred to as an initial position. The pickup
3
reads the TOC data, recognizes the initial position and thereafter moves to a desired address for recording or playback. For accurate reading of signals from the disk, it is necessary to activate a focus servo for focusing the beam on the disk, a tracking servo for accurately tracking record grooves in the disk and a speed servo for rotating the disk at a constant speed based on the synchronization signal recorded on the disk.
If no signal is recorded at the location first exposed to the beam from the pickup
3
, the synchronization signal is undetectable, so that it is impossible to activate the speed servo, consequently failing to effect a proper recording or playback operation subsequently.
Thus, the pickup
3
in the initial position needs to be positioned correctly in the lead-in area.
However, mass production of devices of the type described involves variations in the position or angle of the sensor switch SW mounted on the chassis
4
, therefore entailing the likelihood that the pickup
3
will not be positioned correctly in the lead-in area when halted on pressing the sensor switch SW. It is also likely that the pickup
3
, which is driven by a motor (not shown), will not be located in the lead-in area when in the initial position even if the sensor switch SW is correctly installed in place owing to variations in the drive force of the motor or to variations in the moving load of the pickup
3
. This problem may be overcome by checking every mechanism deck
2
for the installed position of the sensor switch SW, whereas the procedure requires time and labor.
SUMMARY OF THE INVENTION
An object of the present invention is correctly position the pickup in the lead-in area by a simple method when the pickup is in the standby state for recording or playback.
The invention provides a disk recording or playback device which has mounted on a chassis
4
a pickup
3
movable along the signal recording surface of a disk for projecting a beam on the recording surface to detect addresses on the disk, and a sensor switch SW for detecting the pickup
3
as brought to the inner peripheral side of the disk.
The flow charts of
FIGS. 9 and 10
show the outline of the present invention. First, a target region where the pickup
3
is to be positioned initially is provided in the lead-in area of the disk at the inner peripheral side of the disk.
The pickup
3
is moved from the outer peripheral side of the disk toward the lead-in area, reversely moved
5
upon the sensor switch SW detecting the passage of the pickup
3
, and caused to overrun for a predetermined period of time (S
1
) toward the disk outer periphery from a position where the switch SW detects the passage of the pickup
3
again (S
3
).
The pickup
3
reads an address A on the disk after the overrun (S
5
) and is thereafter returned.
The pickup
3
is moved toward the disk outer peripheral side again at least once with the overrun time corrected to a shorter period (S
10
, S
11
) if the address A is beyond the target region toward the disk outer peripheral side, or with the overrun time corrected to a longer period (S
12
, S
13
) if the address A is closer to the disk inner peripheral side than the target region. The period of overrun time is stored which eventually enables the pickup to read an address within the target region (S
16
).
When recording or playback is to be started again, the pickup
3
, as returned to a position closer to the disk inner peripheral side than the sensor switch SW, is moved outward so as to move from the position of detection of the pickup
3
by the switch SW for the stored period of overrun time.
In this way, the pickup
3
can be initially positioned correctly in the lead-in area when the period of overrun time is predetermined for every recording or playback device and the location where the pickup
3
is to be positioned initially is stored therein. The pickup
3
in the standby state for recording or playback can accurately read signals from the disk. This sets the pickup
3
in an ideal initial position to subsequently ensure a smooth recording or playback operation.
REFERENCES:
patent: 0463720 A2 (1991-04-01), None
patent: 2151373 (1985-07-01), None
Armstrong, Westerman Hattori, McLeland & Naughton
Psitos Aristotelis M.
Sanyo Electric Co,. Ltd.
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