JPH11213395A - Track pitch measuring method and search method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discriminate the track pitch of a disk player and to accurately and quickly conduct a search operation by computing a track pitch from the number of revolutions of a stepping motor and the number of tracks between the positions between which a pickup moved. SOLUTION: After a pickup 2 was moved to a recorded position S by a position information signal A, a stepping motor 3 is rotated at a prescribed step number N, the pickup 2 is moved to a prescribed position T of a distance R and a position information B is read. Then, a track number N between positions S and T is obtained from the position information signals A and B at the positions S and T and the linear velocity, which is beforehand measured, the ratio R/N is computed and the track pitch between the positions S and T is accurately measured. Then, the kind of the track pitch of a disk 1 is discriminated, the moving distance of the pickup 2 during a search operation, i.e., thr rotary driving number of the motor 3 is set and the pickup 2 is accurately moved to a prescribed position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for measuring a track pitch of a disk on which a signal is recorded at a constant linear velocity and a search method.

[0002]

2. Description of the Related Art A disk player which performs a reproducing operation by reading out a signal from a disk on which information data such as music is recorded by a digital signal using an optical pickup has become widespread. One of them is a CD player.

As is well known, a disk used in such a CD player has one block (consisting of 98 frames) with a period of 1/75 second in addition to a main data signal such as music information. Is recorded, a sub-data signal called a sub-coding signal is recorded. Such a subcoding signal is composed of eight channels of P, Q to W channels, in which the P channel contains position index information indicating the position of the beginning of the song, and the Q channel has the starting point of the signal track. And the position index information indicating the absolute elapsed time, the elapsed time for each song, the song number, and the like.

[0004] Therefore, the CD player can perform an operation of detecting a position where a desired song or the like is recorded by using the position index information and performing a reproducing operation, that is, an operation called a search. Have been.
Such a search operation is performed by moving the optical pickup in the radial direction of the disc. Such a movement operation is an operation of moving the main body of the optical pickup at a high speed to near the target position, that is, a pickup feeding operation. And an operation of displacing the objective lens constituting the optical pickup, that is, a track jump operation.

[0005] The linear velocity of a disc in a CD player is not a specific velocity but 1.2 m / sec to 1.4 m / sec.
A range of seconds is allowed. Therefore, it is necessary to change the constant used for obtaining the distance to move the optical pickup when performing the search operation according to the value of the linear velocity.

[0006] Recently, a CD called a CD-ROM in which a data signal used for a computer is recorded instead of an audio signal of music or the like is reproduced.
-Disk players called ROM players are widespread. In such a CD-ROM player, a high-speed reading operation of a signal is required, so that the searching operation needs to be performed at a high speed.

[0007]

The search operation in the disc player is performed by calculating the number of tracks from the position information signal of the current position and the position information signal of the target position to the target position, and making an optical system corresponding to the track number. This is done by moving the pickup, but the distance between the signal tracks, ie the track pitch, is not the same for all disks, and some disks have a track pitch of 1.6 microns, 1.5 microns and Some are 1.7 microns. As a result, there is a problem that the moving distance of the optical pickup at the time of the search operation greatly differs due to the difference in the track pitch.

An object of the present invention is to provide a track pitch measuring method and a search method which solve the above problem.

[0009]

According to the present invention, the pickup is moved from the first position to the second position by the rotation of the stepping motor for moving the pickup by a predetermined number of steps, and the number of tracks is increased from the number of tracks between the moved positions of the pickup. The pitch is measured.

[0010]

FIG. 1 is a flowchart showing a track pitch measuring method of the present invention, FIG. 2 is a flowchart showing a track pitch measuring method of the present invention, and FIG. 3 is a block circuit diagram of a disk player according to the present invention.

In FIG. 3, reference numeral 1 denotes a disk on which signals are recorded, which is configured to be mounted on a turntable that is driven to rotate by a spindle motor (not shown). Reference numeral 2 denotes an optical pickup for reading out a signal recorded on the disk 1 by irradiating a signal surface of the disk 1 with a light beam. The optical pickup 2 includes an objective lens, a photodetector, and the like, and has a stepping motor 3. The disk 1 is configured to be moved in the radial direction by rotation.

Reference numeral 4 denotes an RF signal amplifying circuit for amplifying an RF signal obtained from a photodetector incorporated in the optical pickup 2 and shaping the waveform, and reference numeral 5 denotes a signal obtained via the RF signal amplifying circuit 4. The optical pickup 2 performs a focusing control operation for focusing a light beam of the optical pickup 2 on a signal surface of the disk 1 and a tracking control operation for following the light beam on a signal track of the signal surface. The pickup control circuit performs a control operation of a track jump by a displacement operation of the objective lens. The operation is performed by controlling a movement of the objective lens.

Reference numeral 6 denotes a digital signal processing circuit which receives a signal output from the RF signal amplifier circuit 4 and performs demodulation of various signals, and 7 denotes a digital signal processed by the digital signal processing circuit 6. Is a signal reproducing circuit to which a data signal is input, and is configured to output a data signal to the computer device 8.

A system control circuit 9 receives a signal demodulated by the digital signal processing circuit 6 and performs various operation controls in accordance with a switching signal output from the computer device 8. It is configured.

Reference numeral 10 denotes a stepping motor drive circuit for controlling the rotation of the stepping motor 3.
The operation is controlled by a motor control signal output from the system control circuit 9.

The disk player according to the present invention is configured as described above, and the operation will be described next. When the disc 1 is inserted into a storage section provided in a disc player, the disc 1 is placed on a turntable and a focusing control operation for focusing a light beam emitted from the optical pickup 2 on a signal surface is performed. Done.

When the focusing control operation of the optical pickup 2 is performed and the focus is obtained, it is detected that the disk 1 is mounted on the turntable, and the rotation driving operation of the disk 1 by the spindle motor is started. You. When such an operation is started, a focusing control operation and a tracking control operation by the pickup control circuit 5 are performed, and a read operation of disk data recorded on the disk 1 is performed.

The signal read by the optical pickup 2 is input to an RF signal amplifier circuit 4 where it is amplified and shaped, and applied to a digital signal processing circuit 6. After the signal input to the digital signal processing circuit 6 is subjected to digital signal processing, its data signal component is demodulated and input to the signal reproduction circuit 7. The data signal input to the signal reproducing circuit 7 is output to the computer device 8 through the output terminal, and the computer device 8 performs a predetermined signal processing operation.

As described above, the signal reading operation in the present embodiment is performed. Next, a method of measuring the track pitch, which is the gist of the present invention, will be described with reference to the flowchart shown in FIG.

The method shown in FIG. 1 is a method of measuring a track pitch using a position information signal recorded on a disk. First, an operation of measuring a linear velocity of a signal recorded on the disk 1 is performed. (Step A). Such a measurement of the linear velocity can be performed by a method described in, for example, Japanese Patent Application Laid-Open No. 6-111464, and the description thereof is omitted.

When the measurement of the linear velocity is completed, a predetermined position information signal A is recorded in the pickup 3 by the rotation driving operation of the stepping motor 3 by the stepping motor drive circuit 10 and the signal reading operation by the optical pickup 2. Move to position S (step B). When the operation of Step B is performed, an operation of determining whether or not the pickup 2 is at a predetermined position is performed (Step C). If it is determined in step C that the pickup 2 is not at the predetermined position, the operation of step B is performed until the pickup 2 moves to the predetermined position.

If it is determined in step C that the pickup 2 is at a predetermined position, the stepping motor 3 is rotated by a predetermined number of steps (step D). The rotation of the stepping motor 3 is performed, for example, in a direction in which the pickup 2 is moved toward the inner circumference of the disk 1. When the rotation operation of the stepping motor 3 is performed, the moving distance of the pickup 2 moved by the one-step operation can be accurately set. Therefore, the distance of the pickup 2 moved by the predetermined number of step operations is , A predetermined value R.

In the operation of step D, the pickup 2 is moved to the position T, and the operation of reading the position information signal B at the position T is performed (step E). In step E, when the read operation of the position information signal B is performed, the position information signal A at the position S and the position information signal B at the position T, and the number of tracks N between the position S and the position T depending on the linear velocity. Is calculated (step F).

The number of tracks N between the position S and the position T
Is obtained by calculation, the distance between the position S and the position T,
That is, the distance that the pickup 2 moves by the rotation of the stepping motor 3 by a predetermined number of steps becomes a predetermined value R, so that the distance between tracks, that is, the track pitch can be measured by calculating R / N (step). G).

The method of measuring the track pitch using the position information signal recorded on the disk shown in FIG. 1 is performed as described above. Next, the method shown in FIG. 2 will be described.

The method shown in FIG. 2 is a method of measuring a track pitch using a track cross signal obtained when a beam crosses a track while the pickup 2 is moving.

In such a method, first, the pickup 2 is moved to a predetermined position P by the rotation of the stepping motor 3 (step H). The position P may be any position as long as the position is within a range in which the pickup 2 can be moved by the rotation operation of the stepping motor 3 described later.

When the operation of step H is performed, the control operation of the pickup 2 is performed by the pickup control circuit 5, and the focusing operation for focusing the light beam emitted from the pickup 2 on the signal surface of the disk 1 is performed to perform track crossing. A state where a signal is detected is set (step I).

When the track cross signal is detected in step I, the stepping motor 3 is rotated by a predetermined number of steps (step J). The rotation of the stepping motor 3 is performed, for example, in a direction in which the pickup 2 is moved toward the inner circumference of the disk 1. When the rotation operation of the stepping motor 3 is performed, the moving distance of the pickup 2 moved by the one-step operation can be accurately set. Therefore, the distance of the pickup 2 moved by the predetermined number of step operations is , A predetermined value R.

The pickup 2 is moved to the position Q in the operation of step J. During this movement, a track cross signal is detected and the number N is counted (step K).

Number of tracks N between position P and position Q
Is obtained by the detection of the track cross signal, the distance between the position P and the position Q, that is, the distance the pickup 2 moves by the rotation of the stepping motor 3 by a predetermined number of steps becomes a predetermined value R. By calculating / N, the distance between tracks, that is, the track pitch can be measured (step L).

As described above, the track pitch recorded on the disk 1 can be measured by the first method shown in FIG. 1 and the second method shown in FIG. A 0.6 micron disk or
It is possible to calculate and determine whether the disk is a 5-micron disk or a 1.7-micron disk. Accordingly, if the moving distance of the pickup 2 during the search operation, that is, the number of rotation drive steps of the stepping motor 3 is set using the track pitch calculated and determined as described above,
The pickup 2 can be accurately moved to a desired position, and the search operation can be performed quickly.

[0033]

According to the present invention, the track pitch is measured by utilizing the fact that the distance of the pickup moved by the rotation of the stepping motor by a predetermined number of steps can be accurately set, so that the track pitch can be easily measured. With such a configuration, the track pitch can be accurately measured.

Further, according to the present invention, the number of tracks existing during the distance the pickup moves is detected by using the position information signal recorded on the disk, and the track pitch is measured based on the number of tracks. So,
Track pitch can be measured accurately.

According to the present invention, when the pickup is moving, the number of tracks existing during the movement distance of the pickup is calculated using the track cross signal obtained from the pickup, and the track is calculated based on the number of tracks. Since the pitch is measured, the track pitch can be accurately measured.

Further, since the number of rotation drive steps of the stepping motor during the search operation is set based on the obtained track pitch, the search operation can be performed quickly.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a track pitch measuring method of the present invention.

FIG. 2 is a flowchart illustrating a track pitch measuring method according to the present invention.

FIG. 3 is a block circuit diagram of a disc player according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 disc 2 optical pickup 3 stepping motor 5 pickup control circuit 6 digital signal processing circuit 7 signal reproduction circuit 8 computer device 9 system control circuit 10 stepping motor drive circuit

Claims (4)

[Claims] 1. A disc player configured to perform a moving operation of a pickup for reading a signal from a disc on which a signal is recorded at a constant linear velocity by a stepping motor, wherein the stepping motor has a predetermined number of steps. 1st pickup by rotating
A track pitch is measured from the number of tracks located between the positions where the pickup has moved, and the track pitch is measured from the number of tracks between the positions where the pickup has moved. 2. The track pitch according to claim 1, wherein the number of tracks is calculated based on the position information signal of the first position, the position information signal of the second position, and the linear velocity of the recording signal. Measuring method. 3. The first position and the second position are determined by a track cross signal obtained from the pickup during the movement operation of the pickup.
2. The track pitch measuring method according to claim 1, wherein the number of tracks between the positions is calculated. 4. A search method, wherein the number of rotation drive steps of a stepping motor during a search operation is set based on the track pitch measured in claim 1.