JPH0731889B2 - Search method for disc player - Google Patents

Description

TECHNICAL FIELD The present invention relates to a search method in a disc player.

2. Description of the Related Art In a conventional disc player search method, as shown in FIG. 6, by comparing a current address with a target address and repeating a jump operation of a distance set based on the difference, A search (hereinafter referred to as a search) was being performed. That is, first, when the current address and the target address are compared at a point, the current address is smaller than the target address, so a so-called long jump operation of moving the pickup by a relatively long distance in one jump operation is performed in the FWD direction (in the disc). From the circumference to the outer circumference). By repeating this jump operation several times, the information detection point of the pickup reaches the point. At this point, comparing the current address with the target address, this time the current address is larger than the target address, so a so-called short jump operation with a shorter jump distance than the long jump is performed in the REV direction (from the disk outer circumference to the inner circumference). To do. By repeating this jump operation several times, the information detection point of the pickup reaches the point. At this point, when the current address and the target address are compared again, this time, since the current address is smaller than the target address, a so-called 1-track jump in which the information detection point of the pickup skips one recording track of the disc in the FWD direction. To do. This one
By repeating the track jump several times, the information detection point of the pickup reaches the target address (point), and the target address can be searched.

In this way, in the conventional method, a long jump is performed until the target address is passed, so if the final long jump start point is immediately before the target address, the information detection point will be overshooting the target address as much as the long jump distance. In addition to the loss of search time, when searching for an address near the outer circumference of the disc, the information detection point of the pickup sometimes jumped over the lead-out track and jumped to the outer circumference side from the lead-out area. The jumping of the information detection point to the outside of the lead-out area is also caused by a track count error, a jump operation when the disk is eccentric, a jump overshoot, or the like. In some cases, Q data including address information may not be written outside the read-out area, and in the conventional address search method, the jump direction and jump distance are set by comparing the current address and the target address. , There was a possibility that search could not be performed due to the information detection point popping out from the lead-out area.

SUMMARY OF THE INVENTION The present invention has been made to eliminate the above-mentioned drawbacks of the conventional ones, and a search method in a disc player that does not make a search impossible when jumping out from the lead-out area. The purpose is to provide.

The search method in the disc player according to the present invention is
A search method in a disc player equipped with a pickup for reading recorded information from a recording disc to obtain a read signal, comprising: a current position information reading step of reading current position information of the pickup on the recording disc from the read signal; A determination step for determining whether or not the current position information cannot be read according to a search command, and a predetermined pickup when the current position information cannot be read in the determination step. A forcible movement action for forcibly moving to the inner peripheral side of the recording disk by a distance, and a long track jumping process for causing the pickup to make a long track jump in the direction of the target position and beyond the target position after the execution of the forced movement process, After performing the long track jump process Serial pickup and having a short track jump stroke allowed to short track jump in a direction opposite to the said long track jump until reaching the target position.

Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an example of an optical recording disk reproducing apparatus to which the search method according to the present invention is applied. In the figure, a laser beam emitted from, for example, a laser diode 2 in a pickup 1 passes through a prism 3, a tracking mirror 4, an objective lens 5 and the like to become spot light (information detection point), which is a recording track (pit) of a disc 6. (Row) 7 is illuminated. The reflected light of the spot light passes through the objective lens 5, the tracking mirror 4, and the prism 3 and is incident on a so-called four-divided detector 8 including a photodiode or the like built in the pickup 1. The total output of the 4-division detector 8 is the read RF signal.
It is supplied to the demodulator 10 via the RF amplifier 9,
After being demodulated by, the data is supplied to the data extraction circuit 11. In the data extraction circuit 11, address information is extracted from the demodulation output,
The address information is supplied to the controller 12.

Each output of the 4-division detector 8 is also supplied to the tracking error signal generation circuit 13. As a method of generating the tracking error signal, there is a so-called 1-beam method, a 3-beam method, or the like, and the 1-beam method also includes a so-called push-pull method, a heterodyne method, or the like. The tracking error signal generated by the tracking error signal generation circuit 13 is
As shown in FIG. 2, it has a so-called S-curve characteristic of zero crossing at the center of the recording track 7, and a drive coil for the tracking mirror 4 via a mirror drive circuit 14.
By being supplied to 15, the mirror 4 is driven to rotate.

Reference numeral 16 denotes a slider motor that mounts the pickup 1 and drives a slider (not shown) that is movable in the disk radial direction. The motor 16 is driven and controlled by a motor drive circuit 17. The motor drive circuit 17 detects the tilt angle of the tracking mirror 4 based on the output of the mirror drive circuit 14, and the slider motor 16 drives the slider 1 in the disk radial direction so that the tilt angle is zero, that is, the tracking mirror 4 is in the neutral position. Position control.
The mirror drive circuit 14 and the motor control circuit 17 are also drive-controlled by a drive signal issued from the controller 12. The track pulse generation circuit 18 generates one pulse each time the spot light crosses the recording track 7 based on the tracking error signal shown in FIG. 2 when the pickup 1 moves in the disk radial direction, and sends it to the controller 12. . The controller 12 is supplied with an address search command generated by an operation by a user and data indicating a target address from an operation unit (not shown). The controller 12 is formed by a microcomputer including a processor, ROM, RAM, timer and the like. This controller
At 12, the processor is pre-stored in ROM and operates according to a program based on the flowchart of FIG.

Next, the operation of the processor in the controller 12 will be described with reference to the sequence diagrams of FIGS. 4 and 5 and along the flowchart of FIG.

On a recording disc, for example, a so-called compact disc, information indicating the absolute time from the innermost disc to the current position, the information indicating the absolute time from the innermost disc to the head of each song, and the like are recorded. If the address search command is issued when the spot light of the pickup 1, that is, the spot light of the pickup 1 is located at the point (a), the processor extracts the address information extracted by the data extraction circuit 11 (see FIG. 1). The read operation of the current address is performed from (step 1), the current address and the target address are compared only when the current address is read (steps 2 and 3), and the distance between both addresses is larger than a certain value, that is, When it is determined that the target address is far, the number of tracks between the current address and the target address is calculated (step 4). The number of tracks is calculated based on the absolute time of each address, the disk rotation speed, the track pitch, and the like. Then, the processor sets the number N of tracks obtained by this calculation as the number N'of tracks to be counted, and thereafter moves the pickup 1 in the target address direction, in the FWD direction in the example of FIG. 4 (step 5). At this time, if it is determined that the number of tracks N is larger than a certain value n, the value obtained by subtracting the certain value m from the number of tracks N is set as the number of tracks N'to be counted. May be. By this subtraction, when the pickup 1 moves, the spot light of the pickup 1 can be prevented from overshooting the target address due to a calculation error of the number of tracks, a feed overshoot, or the like. Instead of subtracting the constant value m from the track number N, the track number N is set to a constant value l (l
<1) may be multiplied.

The processor counts the number of track pulses generated from the track pulse generation circuit 18 (see FIG. 1) at the same time as the pickup 1 is moved, and if it is determined that the count number has reached the track number N '(step 6). ,
The movement of the pickup 1 is stopped (step 7), whereby the spot light reaches the point (b).

The processor reads the current address again at point (b), compares the current address with the target address (steps 1 to 3), and moves to step 10 when the distance between both addresses is below a certain value The address is compared with the target address. If it is determined in step 10 that the current address is greater than the target address, the processor moves to step 11 and REVs a 100-track jump that jumps the spot light by a distance of 100 tracks.
However, since the current address is smaller than the target address in the example of FIG. 4, step 12 is followed by step 13
Move to and perform a 100-track jump in the FWD direction. The processor repeats this 100-track jump in the FWD direction until it is determined in step 12 that the current address is larger than the target address. As a result, the spot light reaches point (c). Subsequently, the processor makes a 10-track jump in the REV direction until the current address exceeds the target address (steps 14 and 15). When the current address exceeds the target address by this 10-track jump in the REV direction, the processor performs a 1-track jump in the FWD direction until the current address matches the target address or exceeds the target address (step 16, step 1).
7). That is, after the spot light reaches the point (d), the processor converges the spot light of the pickup 1 to the target address by gradually shortening the jump distance according to the result of the comparison of the current address and the target address. is there.

Here, the spot light jumped over the lead-out track due to a calculation error in the number of tracks N, a track number miscount, jump eccentricity, etc. and reached point (d) outside the lead-out area as shown in FIG. I shall. Then, at this point (d), since the address information has not been written, the processor cannot obtain the current address in step 2, and proceeds to step 8 to repeat the read operation of the current address for X seconds. When the current address is not obtained during the read operation of the current address for the X seconds, the processor is forced to shift to the REV direction for a predetermined time (step 9). As a result, the spot light moves in the inner circumferential direction by a predetermined distance and reaches point (e). After this, the processor proceeds to step 10 to move the spot light to point (f) by 100 track jumps and then move the spot light to point (g) by 10 track jumps as in the case of FIG. After this, the processor converges the spot light to the target address by one-track jump.

In addition, checking whether the current address is obtained within X seconds and forcibly moving it in the REV direction when it is not obtained are all performed by track count search, 100 track jump, 10 track jump, and 1 track jump. This is performed at the time of address reading for address comparison before the jump.

As described above, in the search method for the disc player according to the present invention, when the so-called search operation of moving the pickup to the desired target address position is started, the current address position of the pickup cannot be read. It is determined that the pickup is outside the lead-out area of the recording disc, and at this time, the pickup is forcibly transferred to the inner side of the jump, and the pickup is temporarily moved to the data of the recording disc. A jump operation to the target address position is executed again after the user has moved into the recording area. Therefore, even if the search operation is started when the current position of the pickup is outside the lead-out area of the recording disk, it is possible to prevent the search operation from being disabled.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of an optical recording disk reproducing apparatus to which the search method according to the present invention is applied, FIG. 2 is a diagram showing the relationship between recording tracks and tracking error signals, and FIG. 3 is according to the present invention. Flowcharts showing the procedure of the search method in the disc player, FIGS. 4 and 5
FIG. 6 is a sequence diagram showing a search operation according to the present invention.
The figure is a sequence diagram showing a conventional search operation. Description of main parts 1 Pickup 4 Tracking mirror 6 Recording disk 11 Data extraction circuit 12 Controller 13 Tracking error signal generation circuit 18 Track pulse generation circuit

Claims (1)

[Claims] 1. A search method in a disc player having a pickup for reading recorded information from a recording disc to obtain a read signal, wherein a current position information of the pickup on the recording disc is read from the read signal. A position information reading process, a determination process for determining whether or not the current position information cannot be read according to a search command, and a case where it is determined that the current position information cannot be read in the determination process. And a forcible movement process for forcibly moving the pickup a predetermined distance to the inner circumference side of the recording disk, and a long track jump for moving the pickup in the direction toward the target position and beyond the target position after the execution of the forcible movement process. Track jump process and the long track jump Search method in a disk player and having a short track jump stroke allowed to short track jump in a direction opposite to the said long track jump until the pickup after the stroke execution reaches the target position.