JPH02193353A - Identification method for optical disk - Google Patents

Abstract

PURPOSE:To surely identify an optical disk by moving an optical pickup from the innermost peripheral track of an optical disk to the outermost peripheral track, finding a moving range and identifying the optical disk based on the result of measurement. CONSTITUTION:When a CD 1 is set to a loading part, a CPU outputs an operation command to a servo circuit 11 to operate a feeding motor 4. The servo circuit 11 moves an optical pickup 3 to the innermost peripheral track and the CPU outputs a signal range measurement command to the servo circuit 11 when the pickup is moved to the innermost peripheral track. The servo circuit 11 moves the optical pickup 3 toward the outermost peripheral track and starts counting the pulse number of a tracking error signal S3. When the optical pickup 3 is deviated from the outermost peripheral track, an EFM signal S1 is changed and the CPU stops the movement of the pickup 3. Then the pulse of the counted tracking error signal S3 is read and the read pulse number is written in a memory 13a to attain sure identification.

Description

[Detailed Description of the Invention] "Industrial Application Field" This invention relates to compact discs (CDs) for music reproduction.
, relates to a method for identifying optical discs used for identifying laser discs (LDs) for video reproduction, etc.

``Prior Art'' Some recent CD players are known in which the order in which songs are played, the number of times they are played, and the like can be set in advance in memory. When a CD is set in such a CD player, the CD is first identified, and if the CD has a play order set in the memory, it is played according to the set order.

Conventionally, CDs were identified using TOC (Table of C).
content) information. That is, when a CD is set in the player's mounting section, the TOC information of the CD is read and recorded in the memory, and then, when the playing order etc. are specified, the contents are recorded. Then, when the CD is inserted into the player again at a later date, its TOC information is compared with the TOO information in memory, and if it is the same as what was previously recorded, the previously set playback is performed. Reproduction is performed according to the order, etc.

``Problems to be Solved by the Invention'' By the way, there is no problem in disc identification for discs with TOC information, such as the above-mentioned CD, but discs without TOC information, such as LD
However, there is a problem in that the disc cannot be identified by the method described above. Furthermore, CDs also have a problem in that TOC information cannot always be read accurately due to scratches or dirt.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide an optical disc identification method that can identify any optical disc.

"Means for Solving the Problems" This invention provides a method for moving an optical pickup from the innermost track to the outermost track of an optical disc, measuring the distance traveled, and identifying the optical disc based on the measurement result. Features.

"Operation" The width of the area in which signals are recorded on an optical disc differs from one optical disc to another.

Therefore, the present invention measures the width of a signal recording area on an optical disc, and performs identification based on the measurement result.

"Embodiment" Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a CD player according to an embodiment of the present invention.

In this figure,! is a CD, 2 is a spindle motor that rotationally drives the CDI, 3 is an optical pickup that reads digital information recorded by pits on the signal recording surface of the CDI, and 4 is a feed motor that moves this optical pickup 3.

As shown in FIG. 2, the signal recording range of the CDI is from the lead-in start point Ta to the lead-out end point 'rb, and tracks are provided at intervals of 1.6 μm between the lead-in start point Ta and the lead-out end point 'rb. The optical pickup 3 includes a semiconductor laser, an objective lens, an optical sensor, a focus actuator for adjusting the focus of the objective lens, and a CD-ROM as a whole.
It is composed of an i-racking actuator that moves a minute distance in the radial direction of I.

6 amplifies the read signal output from the optical pickup 3 and converts it into EFM (Eight to Fou).
This is an RF amplifier that outputs a signal S1 as a signal S1, and also generates and outputs a focus error signal S2 and a tracking error signal S3 from the read signal. 7 is E
A signal processing circuit 8 performs processing such as demodulation of the FM signal Sl, correction and correction of code errors, and a DA converter 8 converts the digital signal output from the signal processing circuit 7 into an analog audio signal.

Reference numeral 9 denotes an audio circuit that performs processing such as amplification of this audio signal, and the output signal of this audio circuit 9 is outputted to an external speaker or the like via an audio output terminal 10.

Further, 11 is a servo circuit, which controls the CLV (Cons) of the spindle motor 2 under the control of a control unit +3 to be described later
The focus servo of the optical pickup 3 is controlled based on the focus error signal S2 output from the RF amplifier 6.
Similarly, tracking servo of the optical pickup 3 is performed based on the tracking error signal S3. Note that the servo circuit 11 is provided with an oscillation circuit using a crystal oscillator, and the focus actuator and tracking actuator convert the output of this oscillation circuit into P W M (
Pulse W 1dth M odulaL 1o
n) driven by a modulated signal.

The control unit 13 includes a CPU (central processing unit) and
It consists of a ROM in which programs used in the U are stored, a memory 13a for data recording, and a 10 (human output) boat for exchanging data with the outside. As shown in FIG. 3, the memory 13a is provided with a storage area in which the number of pulses is stored corresponding to each CD. Note that data is always held in this memory 13a by a backup MD.

Next, the operation of this embodiment with the above configuration will be explained. It is assumed that the memory 13a is cleared in the initial state.

When the power switch of the player is turned on and then set in the CDI or mounting part by the user, the CPU
This is detected and an operation command is output to the servo circuit 11 to operate the feed motor 4.

The servo circuit II receives this command and moves the optical pickup 3 to the innermost track. When the optical pickup 3 moves to the innermost track, the CPU starts the servo circuit 11.
Outputs the signal range measurement command to.

The servo circuit 11 receives this command and operates the optical pick-up tube 3.
is moved toward the outermost track and starts counting the number of pulses of the tracking error signal S3.

When the optical pickup 3 moves and leaves the outermost track, the signal level of the EFM signal Sl increases. The CPU is
When the level of this EFM signal St becomes high, a stop command is supplied to the servo circuit 11 to stop the movement of the optical pickup 3, and then the counted number of pulses of the tracking error signal S3 is read and this The read number of pulses is written in the storage area corresponding to CDI of the memory 13a.

Next, when the currently set CDI is replaced with another CD, the CPU starts the servo circuit 11 as described above.
Outputs a command to and reads the newly counted number of pulses. Then, the memory 13a is scanned and compared to see if the number of pulses is the same as the already registered number of pulses. If they are the same, no registration processing is performed. If they are not the same, the number of pulses of the newly set CD is written in the storage area corresponding to CD2 of the memory 13a.

In this way, in the embodiment described above, each time each CD is set, the number of pulses corresponding to the signal recording range of that disc is registered. Therefore, in the player, each CD can be identified based on the registered number of pulses.

In the above embodiment, the number of pulses of the tracking error signal S3, that is, the number of trunks, is measured, but instead of this, the time taken for the optical pickup 3 to move from the innermost track to the outermost track is measured. Alternatively, if the feed motor 4 is driven by pulses, the number of driving pulses may be measured. Moreover, as shown in FIG. 4(a),
A magnetic tape 16 on which a pulse-like signal has been previously recorded is pasted below the moving range of the optical pickup 3, and the magnetic tape 16 is read by the magnetic head I7 attached to the optical pickup 3 and converted into pulses. b)), the number of pulses may be counted and stored in the memory 13a.

In the above embodiment, the present invention was applied to a CD player for normal music playback, but it may also be applied to a CD-RO player.
The present invention may be applied to playback devices such as M drive, CD-1, CD-V, and LD.

"Effects of the Invention" As explained above, according to the present invention, the optical pickup is moved from the innermost track to the outermost track of the optical disc, the moving distance is measured, and the optical disc is identified based on the measurement result. This has the effect that the optical disc can be identified regardless of its type.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a CD player according to an embodiment of the invention, FIG. 2 is a diagram showing the signal recording range of a CD, and FIG. 3 is a memory 13a applied to the embodiment of the invention.
FIG. 4 is a diagram showing a modification of the present invention. ! ... Compact disc (optical disc), 3
......Optical pickup, Ta...Innermost track, Tb...Outermost track.

Claims (1)

[Claims] A method for identifying an optical disc, comprising moving an optical pickup from the innermost track to the outermost track of the optical disc, measuring the distance traveled, and identifying the optical disc based on the measurement results.