JPH05234284A - Access method of optical disk device - Google Patents

Abstract

PURPOSE:To reduce the required time for an access while moving an optical pickup to a designated position by computing the number of moving tracks corrected by the linear velocity compensation coefficient corresponding to the recording linear velocity of the disk actually being used. CONSTITUTION:When a first access command is generated from an access command means 1 after a disk is loaded, an access track number is obtained using a track number conversion table corresponding to a specific linear velocity of a track number storage means 2 and an optical pickup is moved by this number. Based on the difference between the position after the move and the designated position, a line speed compensation coefficient computation means 7 obtains a line speed compensation coefficient (K) corresponding to the recording linear velocity of a specific disk being used. For the access command after a second time, access is made by the number of tracks compensated by the coefficient (K) so as to eliminate correction operations of the access process caused by the errors in a recording linear velocity and the required time for access is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for accessing an optical disc device used for an optical information recording device such as a compact disc.

[0002]

2. Description of the Related Art Conventionally, a method of moving (hereinafter referred to as "accessing") an optical pickup to a designated position address in an optical disc device of this type has a structure shown in FIG. In FIG. 3, when an access command to a certain specified position is output from the access command means 101, a conversion table for converting an address representing the continuous time from the playing start point of the disk into the number of tracks is stored. Using the conversion table of the number storage means 102, the moving track number calculation means 103 converts the current performance position address of the optical pickup and the designated position address instructed to access into the number of tracks starting from the performance start point of the disc. , The number of access tracks is calculated from the difference between them. Based on the calculation result, the optical pickup moving means 10
4, the optical pickup moves, and the address detecting means 1
In 05, the address of the position after movement is detected. If the moved address is at the playable position with respect to the designated position address, the access processing is terminated and the reproducing means 106 operates to start the performance. If the moved address is not the performance start position with respect to the designated position address, the moving track number calculation means 103 and the optical pickup movement means 104 again cause the optical pickup to reach the performance start position with respect to the designated position address. Until then, the same operation as above is repeated.

[0003]

However, in such an access method of the conventional optical disk device, the conversion table used for calculating the number of access tracks is a specific value having a linear velocity at the time of recording data on the disk. Therefore, if the recording linear velocity of the disk actually used does not match the specific value, an error will occur in the calculation of the number of moving tracks. The standard for the recording linear velocity of a compact disc (CD) that is actually commercially available is 1.3 ±
It is 0.1 m / sec. Therefore, in order to correct the above error, it is necessary to repeat the movement operation of the optical pickup by the time the optical pickup reaches the playable position with respect to the designated position address, which causes a problem that the access processing takes a long time. there were.

The present invention solves such a conventional problem, and an object of the present invention is to provide an excellent access method for an optical disk device, which can shorten the time required for access.

[0005]

In order to achieve the above object, the present invention uses an track number conversion table corresponding to a certain specific linear velocity when the first access command is issued after the disk is loaded. Calculate the number, move the optical pickup by this number, and find the linear velocity correction coefficient corresponding to the recording linear velocity peculiar to the disc in use from the difference between the position after the movement and the designated position. On the other hand, the number of access tracks calculated using a track number conversion table corresponding to a certain specific linear velocity is moved by the corrected access track number corrected by the linear velocity correction coefficient. ..

[0006]

Therefore, according to the present invention, by correcting the number of moving tracks corrected by the linear velocity correction coefficient corresponding to the recording linear velocity of the disk actually used, the correction operation of the access process due to the error of the recording linear velocity can be performed. Since it disappears, the time required for access can be shortened.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram showing the configuration of the embodiment. In FIG. 1, reference numeral 1 denotes an access command means, which outputs an access command for moving the optical pickup to a certain designated position. Reference numeral 2 denotes a track number storage means, which stores a conversion table for converting an address representing a continuous time from a performance starting point of a disc into a track number based on a certain specific recording linear velocity. Reference numeral 3 is a moving track number calculating means, which calculates the number of access tracks of the optical pickup by using the conversion table of the track number storing means 2 according to the access command of the access command means 1.
An optical pickup moving unit 4 moves the optical pickup by the number of access tracks calculated by the moving track number calculating unit 3. Reference numeral 5 is an address detecting means for detecting the address of the optical pickup position after the movement. Reference numeral 6 is a reproducing means, which reproduces the disc when the position of the optical pickup is a playable position with respect to the designated position address. Reference numeral 7 denotes a linear velocity correction coefficient calculation means, which calculates a linear velocity correction coefficient corresponding to the recording linear velocity of an actually used disc and corrects the number of tracks calculated by the moving track number calculation means 3. Reference numeral 8 is a microcomputer, which performs overall control of access processing based on an access command.

Next, the operation of the above embodiment will be described. When the access instruction means 1 issues an access instruction when the linear velocity correction coefficient of the disk is not obtained, such as the state immediately after the disk is mounted in the optical disc device,
The moving track number calculating means 3 calculates the number of access tracks of the optical pickup. That is, an address (NTIN) indicating a running time starting from the performance starting point at the current position of the optical pickup and an address (ATIN indicating the running time starting from the playing starting point at the designated position to be accessed).
P) by using a conversion table for converting an address into the number of tracks based on a certain specific linear velocity stored in the number-of-tracks storage means 2, respectively.
Converted to TNA), and the difference between them is used as the number of access tracks (DTN0). Then, the optical pickup moving means 4 moves the optical pickup by the number of access tracks, and the address detecting means 5 detects the address of the moved optical pickup. Here, if the recording linear velocity of the disk being used does not match the specific linear velocity in the conversion table of the track number storage means 2, the optical pickup has not reached the target designated position address and the linear In the speed correction coefficient calculation means 7, the number of access tracks (DT) from the position after further movement to the designated position
N1) is calculated to obtain the linear velocity correction coefficient (k). The method of calculating the linear velocity correction coefficient (k) will be described below.

Here, the number of access tracks (D) at the true recording linear velocity of the disc mounted in the optical disc device.
TNT) and the number of access tracks (DTN0) by the conversion table of the track number storage means 2 are respectively approximated to be proportional to the recording linear velocity, DTNT
= DTN0 × k, and D
TNT-DTN0 = DTN1, and the linear velocity correction coefficient (k) is k = (DTN0 + DTN1) / DTN0 = 1 + DTN1.
It is represented by / DTN0.

In the approximation that the recording linear velocity is proportional to the number of tracks, the disc mounted in the optical disc device has a unique linear velocity correction coefficient (k) expressed by the above equation in accordance with its specific recording linear velocity. ) Will have.

Next, the linear velocity correction coefficient (k) is fed back to the moving track number calculating means 3, and when the access command means 1 again gives an access instruction, the moving track number calculating means 3 performs the same operation as described above. The number of access tracks (DTN0) obtained using the conversion table of the track number storage means 2 is multiplied by the linear velocity correction coefficient (k),
The number of corrected access tracks (DTNK) is calculated. Then, the optical pickup moving means 4 moves the optical pickup by the number of corrected access tracks (DTNK),
The address detecting means 5 detects the address of the optical pickup after the movement. Here, since the corrected access track number (DTNK) is corrected by the unique linear velocity correction coefficient (k) corresponding to the recording linear velocity peculiar to the disc being used, the address after access is the designated position address. On the other hand, the disc can be reproduced by the reproducing means 6 immediately after the access without being subjected to the correction access process. Thereafter, until the disc is replaced with another disc, the number of corrected access tracks (DTN) is determined by the linear velocity correction coefficient (k) obtained above.
By calculating K) and performing the access processing, it is not necessary to perform the correction access processing, and the access required time can be shortened.

Next, FIG. 2 is a flow chart showing a control flow of the microcomputer 8. When a disc is loaded in the optical disc device, an initial value is set, the linear velocity correction coefficient (k) is set to "1", and a flag (AC2FLG) for identifying the number of access commands is set to "0". If there is a first access command after the disk is mounted, the address of the current position and the address of the designated position are compared in step 11, and if access is required, the process proceeds to step 12 and the number of tracks of the specific linear velocity is set. The number of tracks at the current position (DTNN) is calculated based on the conversion table, and in step 13, the number of tracks at the specified position (DNN) is calculated.
TNA) is calculated. Next, in step 14, the number of access tracks (DTN0 = (DTNN-DTNA)
Xk) is calculated, and in step 15, DTN0 is compared with a predetermined number N (correction calculation is performed if this value or more). When DTN0 is larger than N, the process proceeds to step 16, and when DTN0 is smaller than N, the process proceeds to step 21 without performing the correction calculation and the optical pickup is moved. In step 16, since AC2FLG = 0,
In step 17, AC2FLG is set to "1", and in step 21, the optical pickup is moved.

The position after the movement of the optical pickup is newly set as the present position, and in step 11, the present position and the address of the designated position are compared again. If there is no need for access and the current position is the playable position, the process immediately goes to the reproduction processing routine. If access is required, the process proceeds from step 12 to step 16 in the same manner as above. In this case, in step 14, the number of access tracks (DTN1 = (DTNN
−DTNA) × k) is calculated, and in step 16, AC
Since 2FLG = 1, the process proceeds to step 18.

In step 18, when k = 1,
In step 19, the linear velocity correction coefficient (k = 1 + DTN1 /
DTN0) is calculated, and in step 20, the corrected access track number (DTNK = DTN1 × k) is calculated. As a result, the linear velocity correction coefficient (k) peculiar to the disk currently being used is determined, and the access processing from the next time is performed in step 1
The correction track number is calculated in step 4, and the linear velocity correction coefficient (k) is already calculated in step 18 and is not "1". Therefore, the process immediately proceeds to step 21, and the linear velocity unique to the disk is accurately determined. In addition, the optical pickup can be moved to the designated position.

As described above, according to the above-described embodiment, the linear velocity correction coefficient (k) corresponding to the recording linear velocity of the disc is obtained during the first access process after the disc is mounted, and the second and subsequent access processes are performed. , Linear velocity correction coefficient (k)
The correct access track number corrected by is calculated, and the correction operation of the access process due to the error in the recording linear velocity is eliminated, so that the access time can be shortened.

[0017]

As is apparent from the above embodiment, the present invention finds a linear velocity correction coefficient corresponding to the recording linear velocity peculiar to the disk used, and corrects the linear velocity correction coefficient from the current position. By calculating the number of access tracks up to the designated position, it is possible to perform accurate access processing that does not require correction processing, and thus it is possible to shorten the access required time.

[Brief description of drawings]

FIG. 1 is a block diagram of an access method of an optical disc device according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the CPU in the embodiment.

FIG. 3 is a block diagram of a conventional optical disk device access method.

[Explanation of symbols]

 1 access command means 2 track number storage means 3 moving track number calculating means 4 optical pickup moving means 5 address detecting means 6 reproducing means 7 linear velocity correction coefficient calculating means 8 microcomputer

Claims (1)

[Claims] 1. The number of access tracks when a recording linear velocity for recording information on a disc is set to a specific value in response to a first access command for moving an optical pickup to a designated position on the disc is calculated. By moving the optical pickup by this number, the address difference between the moved position and the designated position is detected, and the recording linear velocity peculiar to the disk in use is estimated from this difference, An access method for an optical disk device, wherein a correction coefficient is obtained, and the optical pickup is moved by a corrected access track number obtained by multiplying the access track number obtained from the specific recording linear velocity with respect to the second and subsequent access commands by the correction coefficient.