JPH01204278A - Search method in optical disk player - Google Patents

Abstract

PURPOSE:To reduce a track jump number and to shorten a time to be needed for a search by detecting displacing quantity from the center of the disk of a pick-up and calculating the remaining track number. CONSTITUTION:When thread-sending is executed, based on the output pulse signal of a displacement sensor 4a, a radius ra corresponding to the displacing quantity from the center of a CD 1 of a pick-up 3 in a present position Pa is obtained and an exact linear velocity v0 in the present position Pa can be obtained from this radius ra, etc. Accordingly, a remaining track number N up to a target position Pb can be exactly calculated and the thread-sending can be executed to a position P1 which is extremely near the target position Pb. Thus, the number of the following track jumps is reduced and the time to be needed for the music search is shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to optical disc players such as CD (compact disc) players, and in particular to a search method that can quickly locate the beginning of a song. Seki 4゛ro.

``Prior Art'' Conventionally, when bending a CD by moving its optical pickup from the inner circumferential side to the outer circumferential side of the CD in a CD player, the operating procedure is as shown in FIG. there were.

In this figure, RIA is the lead-in area provided on the innermost side of the CD, MA is the music area where musical tone information is recorded, ROA is the lead-out area, Pa is the current position, and Pb is the target position. There is.

First, at startup, the absolute time information of the start points of the six songs (information indicating the elapsed time from the start point at which the brightest song starts) is read from the lead-in area RIA of the CD, and RAM (Random Access memory). Next, at the time when the bend-ch is commanded, the number of tracks N to move to the target position 1) b is calculated from the absolute time ta of the current position Pa and the absolute time tb of the target position Pb as follows. do.

Zunai Tsushi, the linear velocity of the disk is V. , P is the Torasoku Pidge, and r is the innermost radius (the starting point of the first song), which is the basic thread of the disc. , the radius to be determined is r, the elapsed time is t, the number of tires is N, and π(r”−r
o2) -,. -t 11. -8(+), so by transforming equation (1), r= (ro”+
P ・vo-t/yr )”” --(2)
The following formula is obtained.

Substitute the absolute time ta of the current position Pa and the absolute time [b of the target position 1) b into the elapsed time t of the above equation (2), and calculate the radius ra of the current position Pa and the radius rb of the target position Pb.
Find out. The radii ra and rb obtained by this are N
= rb ra , ・ , ,
, (3)I] By substituting into the formula, the number of tracks N is calculated.

Based on the number N of tracks calculated in this manner, the pickup is moved according to the operating procedure of steps ① to ② shown below, and a song search is performed.

- Move the pickup toward the outer circumference by feeding the thread to positions P,' near the target position pb.

■Read the absolute time information from the current position Pl', and if the target position pb has not been reached, this target position 1) b
100 track jumps toward the outer periphery (
100) Move the rack) repeatedly. In the illustrated example, until passing the target position Pb, P,'-
P,',P,'-+-p3',P3'-+ P,'
He repeated the 100 track jump three times.

(2) Once the target position Pb has been passed, a 10-track jump is performed in the opposite direction (inner circumferential direction).

In the illustrated example, until passing the target position Pb,
P4'→P,',P,' →P e',P e
'→P7' and 10 track jump are repeated three times.

■When passing the target position pb, move in the outer circumferential direction by ■track jump, and thereby the target position p
You'll reach b.

"Problems to be Solved by the Invention" By the way, in the conventional song search method described above, when feeding the thread, it is assumed that the value of the linear velocity Vo of the disk is always constant, and the number of tracks N to the destination position Pb is was calculated. However, in reality, the linear velocity V of this disk. has a width of 12 to 1.4 m/s according to the CD standard, and the number of trunks after 60 minutes from the innermost circumference of the disc is: 17595 when v = 1.2 m/s) Rack vo=
In the case of 1.3 m/s, 18656 tracks ■o=
l, 4 m/s, the linear velocity V, such as 19685 tracks. It changes depending on the value of .

Therefore, if the thread is fed based on the calculation result of the number of tracks N described above, an error will occur and the target (4 position Pb
The thread will be sent to a position far from the target position, and the number of subsequent track jumps will increase (in the worst case, each of the track jumps described in ■ to ■ above will require 9 times). There was a problem in that it took a long time to reach Pb, that is, to bend.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a search method for an optical disc player that can reduce the time required for searches such as finding the beginning of a song.

"Means for Solving the Problem" The present invention moves an optical pickup to the vicinity of a target position by thread feeding, and then reads absolute time information from a reference position recorded on each part of a disk by the optical pickup, In a search method for an optical disc player that searches for a target position by jumping, when thread-feeding the pickup, the amount of displacement of the pickup from the center of the disc is detected, and absolute time information of the current position from the disc is detected. is read, and then the displacement amount and
The number of remaining tracks to the target position is calculated based on the absolute time information of the current position and the absolute time information of the target position, and the number of tracks remaining to the target position is calculated based on the calculation result. It is characterized by

According to the above search method, when feeding the thread, the displacement m (radius) of the pickup from the center of the disk at the current position is detected, and based on this displacement amount, etc., the remaining distance to the target position is calculated. Since the number of tracks is calculated, the number of tracks can be calculated accurately, which allows the thread to be sent very close to the target position, and as a result, the number of subsequent track jumps can be reduced. , the time required for searching, such as finding the beginning of a song, can be reduced.

"Embodiments" Hereinafter, embodiments 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 to which an embodiment of the present invention is applied. In this figure, l is a CD, 2 is a spindle motor that rotationally drives the CDI, and 3 is a spindle motor that rotationally drives the CDI.
4 is an optical pickup that reads digital information recorded in bits on the CDI, and 4 is a feeding mechanism that moves the pickup 3 in the radial direction of the CDI, and a linear pulse smoke is used as its driving source. There is.

The feeding mechanism 4 is provided with a displacement sensor 4a that detects the position of the pickup 3, that is, the displacement amount (corresponding to the radius) from the center of the CDI.

The displacement sensor 4a is configured to be movable relative to the stator by reading a magnetic pattern provided on the movable element side using a magnetic sensor provided on the stator side of the linear pulse smoke constituting the feeding mechanism 4. The relative displacement amount of the child is detected and a pulse signal corresponding to this displacement m is output. Second, the above-mentioned pickup 3 is provided with a +1 signal by a semiconductor laser, a lens, an optical sensor, a focus/tracking controller, a adjustment mechanism, etc. The read signal output from this pickup 3 is outputted by an nF amplifier. After being amplified in step 5, a signal processing circuit 6 performs processing such as demodulation, code error correction, book registration, etc., and a D/A (digital/analog) converter 7 converts the signal into an analog audio signal. The audio signal output from the D/A converter 7 is subjected to processing such as amplification in the audio circuit 8, and then output to an external speaker or the like via an output terminal 9.

In addition, IO is a servo circuit, which controls the rotation of the spindle motor 2 (constant linear velocity control), the focus/tracking control of the pickup 3, and the feed based on control signals supplied from the microcomputer 11, which will be described later. Controls the movement of the mechanism 4.

In this case, the displacement sensor 4a is used to control the movement of the feeding mechanism 4.
A pulse signal output from the oscillator is also used.

11 is a microcomputer that controls the operation of each part of the CD player, and includes a CPU (central processing unit) and this C
ROM (read-only memory) that stores programs used in the PU, and RAM that temporarily stores various data.
and an l10 (human output) boat that exchanges data with the outside.

This microcomputer 11 has r? Noyanbu information corresponding to the number of moving tracks of the pickup 3 is supplied from the F amplifier 5, and the signal processing circuit 6 supplies the CD
Absolute time information read from each part of the pickup 3 is supplied, and a pulse signal corresponding to the displacement of the pickup 3 from the center of the CDI is supplied from the displacement sensor 4a.

12 is an operation button that gives various operation commands to the microcomputer 11; 13 is an operation button for the microcomputer 11;
This is a display device that performs various displays based on display commands supplied from.

Next, the operation procedure when performing a song search in the above-described configuration will be explained with reference to FIG.

First, at startup, the microcomputer 11
The absolute time information of the start points of the three songs is read from the lead-in area RIA of the DI, and this absolute time information is written into the internal RAM.

Next, when the operation button 12 is operated and a song search is commanded, the amount of displacement from the center of the CDI at the current position Pa, that is, the radius ra, is determined based on the pulse signal output from the displacement sensor 4a. The radius ra and the absolute time ja read from the current position Pa are calculated using the following formula (4
) and the elapsed time t, the current CDI linear velocity ■. seek.

−π(r”ro”), = −(4
)-P Linear velocity ■ obtained from this. is substituted into the above-mentioned equation (2), and then the target position Pb is calculated according to the elapsed time of the equation (2).
Substituting the absolute time tb of target position 1) half of b: u
Find rb. By substituting the radius rb obtained thereby and the radius ra of the current position P a obtained based on the output pulse signal of the displacement sensor 4a into the above-mentioned equation (3), it is possible to accurately reach the target position Pb. The number of tracks N is calculated. Based on the number N of tracks calculated in this manner, the pickup 3 is threaded to the vicinity of the target position pb.

From then on, 1001-rack jump as before.

101. Repeat the rack jump, 1 track jump, and then perform the bend-ch.

However, reading the absolute time information from the current position P1,
[] If target position pb has not been reached, this target position p
Perform 100 track jumps toward the outer circumference until passing point b. In the illustrated example, one 100 track jump is performed from P to -P2 until the target position pb is passed. Next, when passing the target position pb,
This time, perform an IO track jump in the opposite direction. In the illustrated example, P until passing the target position pb.

-+-p3. 10 track jumps are repeated three times: p3-P, , P, -P5. Next, target position 1)
When the pickup 3 passes point b, the pickup 3 moves in one track jump toward the outer circumference, and thereby the pickup 3 reaches the target position 1)b.

According to the embodiment described above, when feeding the thread, the current position P is determined based on the output pulse signal of the displacement sensor 4a.
Displacement m of pickup 3 from the center of CD1 at a
A radius ra corresponding to . Since the remaining track number N to the target position pb can be calculated accurately, the thread can be sent to the position P1 extremely close to the target position Pb, and as a result, the subsequent track jump fewer times than before,
The time required for bending is shortened.

In the embodiment described above, after the thread is fed, the track jump is repeated a plurality of times to move to the target position Pb. The number of remaining tracks to the target position Pb may be calculated based on this calculation result, and the movement to the target position pb may be performed in one track jump. In addition, in the above-mentioned embodiment, a case was described in which the application is applied to a CD player for normal music playback to find the beginning of a song. , CI)-V (compact disc video), LD (laser disc), etc., and may be used to cue various data and videos.

"Effects of the Invention" As explained above, according to the present invention, when the pickup is thread-fed, when the amount of displacement of the pickup from the center of the disk is detected, the absolute time information of the current position is transmitted from the disk to the disk. Then, based on the amount of displacement, the absolute time information of the current position, and the absolute time information of the target position, the number of remaining tracks to the target position is calculated, and based on this calculation result, the number of tracks remaining to reach the target position is determined. Since the thread is fed close to the position, it is possible to accurately calculate the number of remaining tracks to the target position when feeding the thread, and this allows the thread to be fed extremely close to the target position. As a result, the number of subsequent track jumps is reduced, and the time required for searches such as finding the beginning of a song can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a CD player to which a search method according to an embodiment of the present invention is applied, FIG. 2 is a diagram for explaining the operating procedure of the search method according to the embodiment, and FIG. FIG. 2 is a diagram for explaining the operating procedure of a conventional search method. ! ...CD, 2...Spindle motor, 3.
...Optical pickup, 4...
Feeding mechanism, 4a...Displacement sensor, 5...
RF amplifier, 6...signal processing circuit, IO...
Servo circuit, 11...Microcomputer.

Claims (1)

[Claims] After an optical pickup is moved to the vicinity of the target position by thread feeding, the target position is searched by track jump while reading absolute time information from a reference position recorded on each part of the disk by the pickup. In a search method for an optical disc player, when thread-feeding the pickup, the amount of displacement of the pickup from the center of the disc is detected, the absolute time information of the current position is read from the disc, and then the displacement is detected. The number of remaining tracks to the target position is calculated based on the absolute time information of the current position, and the absolute time information of the target position, and based on this calculation result, the pickup is moved to the vicinity of the target position. A search method in an optical disc player characterized by thread feeding.