JPS613329A - Track retrieving device - Google Patents

Abstract

PURPOSE:To perform stable and accurate jumping retrieval by providing a means which inhibits the jumping operation for a prescribed period with respect to track retrieval on the surface of a recording carrier where tracks of rugged structure are provided and information can be optically recorded and reproduced. CONSTITUTION:The optical beam emitted from a light source 1 is irradiated to a disc 25, which is rotated by a motor 6, through a converging lens 5. The disc 25 has tracks of rugged structure, and the reflected light from the disc 25 is detected by a photodetector 8 and is supplied to a differential amplifier 9 and a synthesizing circuit 14. The output of the amplifier 9 is supplied to a tracking element 13 through a switch 11 to perform the tracking control. The output of the circuit 14 is supplied to an address mark detecting circuit 24, and a jumping inhibition signal is outputted to a gate circuit 23 in accordance with a detected address mark by an inhibition period setting circuit 22. Consequently, a jumping signal of a jumping signal generating circuit 18 is inhibited for a prescribed period, and stable and accurate jumping retrieval is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optically recordable and reproducible record carrier having tracks on which signals are recorded or tracks provided in advance for recording signals. a converging means for irradiating a light beam generated from a light source in a substantially predetermined convergent state; and a converging means for moving in a direction substantially perpendicular to the track and substantially parallel to the surface of the record carrier. a driving means, a detection means for detecting the positional relationship between the light beam in a predetermined converged state and the track, and a drive means for detecting the positional relationship between the light beam in a predetermined converged state and the track; The drive.

The present invention relates to an optical recording/reproducing apparatus which has a tracking control means and has a function of moving a light beam in a predetermined converged state from one track to another track by a driving means to perform a jumping search.

Conventional Structures and Problems There are various types of record carriers used in optical recording/reproducing devices, including disc-shaped P, M, and M discs.

Tracks are formed on the surface of a substrate such as A (commonly known as acrylic) with a concentric uneven structure, and an optically recordable and reproducible recording material film is formed on the surface of the substrate by means such as vapor deposition. (hereinafter referred to as disk).

In the following description, for convenience, the circumferential direction of the concentric tracks will be referred to as the track direction.

FIG. 1 shows an example of the configuration of a conventional tracking control and track search device using such a disk.

A light beam generated from a light source 1 such as a semiconductor laser is collimated by a coupling lens 2, then reflected by a polarizing beam splitter 3, and a λ/4 plate 4 () passes through a wavelength of the light beam. , a disk 7 whose structure is detailed after being rotated by a motor 6, by a converging lens 5
It is focused and irradiated.

The reflected light from the disk 7 is transmitted through a converging lens, etc., and a λ/4 plate 4.
, passes through the polarizing beam splitter 3, and is irradiated onto a photodetector 8 having a two-split structure.

The differential amplifier 9 outputs a difference signal between the two signals.

The direction of the dividing line of the photodetector 8 having a two-part structure, the direction of the track for the light beam when the light beam is converged and irradiated onto the track, and the direction of the track with respect to the light beam when the light beam is converged and irradiated onto the track, and the direction of the light reflected from the disk 7 are directed to the photodetector 8.
The direction of the dividing line of the photodetector 8 with respect to the light beam irradiated upward is set to match.

The difference signal output from the differential amplifier 9 at this time is
It is well known that the signal representing the relative positional relationship between the upper light beam and the track, ie, the tracking control signal, will not be described in detail.

The signal from the differential amplifier 9 is sent to a phase compensation circuit 10 for compensating the phase of the tracking control system, a switch 11 for disabling tracking control, and a drive circuit 1 for power amplification.
2 to the tracking element 13.

The tracking element 13 is configured to move the converging lens 5 approximately in the radial direction of the disk 7 in accordance with the output signal of the drive circuit 12, and when the switch 11 is short-circuited, the light beam follows the track. The converging lens 5 is controlled so as to.

The outputs of the two-divided photodetectors 8 are also input to the combining circuit 14, and the combining circuit 1411-i outputs the sum signal of the outputs of the two-divided photodetectors 8 to the output terminal 1411-i.
Output to 5.

It will be understood from a capacitive perspective that the sum signal outputted from the output terminal 15 represents the amount of light beam reflected from the disk 7.

Next, a jumping operation will be described in which the light beam is instantaneously moved from the track that the light beam is following to an adjacent track to follow it.

When performing jumping, specify whether to perform a jumping operation to a track adjacent to the inner circumference of the track currently being followed by the light beam, or to a track adjacent to the outer circumference. The shirtping direction indication signal is sent to the jumping direction indication circuit 1.
6 to the jumping signal generation circuit 18, and a jumping start instruction signal for instructing the start of a jumping operation is input from the jumping start instruction circuit 17 to the jumping signal generation circuit 18 and the switch control circuit 19.

The jumping signal generation circuit 18 sends a jumping signal to the drive circuit 12 to move the tracking element 13 toward the inner adjacent track or the outer adjacent track in accordance with the jumping direction instruction signal and the jumping start instruction signal.

The drive circuit 1°2 moves the light beam approximately onto the adjacent snoring link in accordance with the jumping signal.

The switch control circuit 19 receives a jumping start instruction signal from the jumping start instruction circuit 17, and opens the switch 11 only approximately during the jumping operation period.
Disable tracking control.

More specifically, when a positive signal is applied from the jumping signal generation circuit 18 to the tracking element 13 via the drive circuit 12, the light beam moves in the inner circumferential direction on the disk 7. A signal is sent from the identification signal jumping signal generation circuit 18 to the drive circuit 12.
If the light beam is set to move in the outer circumferential direction on the disk 7 when applied to the tracking element 13 via the The instruction circuit 16 sets the jumping direction instruction circuit to HIGH.

Subsequently, when the jumping start instruction signal from the jumping start instruction circuit 17 changes from LO to HIGH, the jumping signal generation circuit 18 detects the rise of the jumping start instruction signal and moves the light beam to the inner adjacent track. A jumping signal is input to the drive circuit 12.

More specifically, when performing a jumping operation to an adjacent track on the inner circumference side, the jumping signal generating circuit 18 first generates an acceleration pulse of a constant positive width W1 to accelerate and move the light beam toward the inner circumference on the optical disk 7. Immediately upon reading, a negative deceleration pulse having the same width W1 as the acceleration pulse is generated to decelerate the light beam moving in the inner circumferential direction. At this time, the width W1 of the acceleration pulse and deceleration pulse is set so that the light beam is located approximately on the inner adjacent track.

When the jumping start instruction signal changes from LOW to f(IGH), the switch control circuit 19 closes the switch 11 for a period of 2 Wl, that is, from the time the acceleration pulse is applied to the tracking element 13 until the end of the application of the deceleration pulse. Open to disable tracking control.

Therefore, after the light beam is positioned approximately on the inner adjacent track due to the acceleration pulse and the deceleration pulse, the tracking control is activated immediately so that the light beam is accurately positioned on the inner adjacent track. The jumping operation ends.

In general, it is impossible to form concentric tracks in perfect circles on the disk, resulting in meandering or distortion.

When such a disk 7 is rotated by the motor 6, eccentricity occurs. Therefore, during the jumping operation, the distance that the light beam moves on the disk 7 varies depending on the position of the light beam on the track or the position of the light beam on the disk. Therefore, it is impossible to accurately position the vehicle on the adjacent track using only acceleration pulses and deceleration pulses of a certain width.As mentioned above, the tracking control is operated immediately after the acceleration pulse and the bar hub, so that the position can be accurately positioned on the adjacent track. Position the light beam.

When the light beam is to be jumped to an adjacent track on the outer circumferential side, the jumping direction instruction signal is set to LOW, and the jumping start instruction signal generates an acceleration pulse of a constant negative width W1, followed by an acceleration pulse of the same positive width. A deceleration pulse W1 is output from the jumping signal generation circuit 18, and the light beam 1d is located approximately on the adjacent track on the outer circumferential side, and is immediately opened by the switch control circuit 19 during the period from the start of the acceleration pulse to the end of the deceleration pulse. The switch 11 is short-circuited, and the tracking control allows the light beam to be accurately positioned on the adjacent track on the outer circumferential side.

Further, when the light beam is moved to a track distant from the track where the light beam is currently located, this is accomplished by performing the above-described jumping operation in reverse.

A configuration diagram of the disk 7 is shown in FIG.

On the disk 7, a plurality of tracks (shaded portions in FIG. 2) having an uneven structure are formed concentrically.

Each track on the disk 7 includes an arcuate tracking track section 20 for recording a signal or reproducing a signal recorded on the disk 7 by tracking a light beam, and an arcuate tracking track section 20 for tracking a light beam or reproducing a signal recorded on the disk 7. It also includes an arcuate address section 21 for identifying a specific block. In order to increase the area on the disk 7 in which signals can be recorded, the address section 21 is formed of each concentric track and is usually sufficiently short compared to the tracking track section 20.

In the following description, for the sake of simplicity, it is assumed that each track has only one address section arranged in a straight line in the radial direction of the disk.

FIG. 3 is an enlarged configuration diagram of the portion indicated by the broken line in FIG. 2.

The tracking track portion 16 is composed of grooves with a uniform depth d, and is set so that d=λ/(8·N) where λ is the wavelength of the light beam used and N is the refractive index of the base material. ing.

On the other hand, the address section 21 is formed of a bit string having a convex-concave structure.

When the light beam in a predetermined convergence state is located on the focal point on the Dinuk 7, the amount of reflected light from the disk 7 will be different than when the light beam is located on a portion without pits. Known.

Therefore, the signal of the address section, which is composed of a row of uneven pits, is read from the sum signal of the output terminal 15 described above.

However, even if the relative positional relationship between the light beam and the track is the same, if the amount of reflected light from the disc area changes, the output signal of the differential amplifier 9, that is, the trunking control signal, changes.

Therefore, in the conventional device, a change in the amount of reflected light that occurs when the light beam is positioned at the address section 21 acts as a disturbance on the tracking control system, causing a tracking control error.

Therefore, when the above-mentioned jumping operation is performed, the light beam moves almost onto the adjacent track due to the acceleration and deceleration pulses, and when the switch 11 is short-circuited again, the light beam is positioned on the address section 21 of the adjacent track. In this case, due to a change in the scenery of the reflected light from the address section 21, the tracking control pull-in to the adjacent track becomes worse, the jumping operation becomes unstable, and in the worst case, the tracking control pull-in to the adjacent track fails, The drawback was that the light beam moved to distant tracks.

In addition, the light beam was located on the address section 21 immediately before the jumping operation, and the jumping was performed with a tracking control error, and the light beam was located at a position far away from the adjacent track due to the acceleration and deceleration pulses. In this case, the jumping operation becomes unstable as well.

OBJECTS OF THE INVENTION An object of the present invention is to eliminate the instability of the jumping operation caused by the change in the amount of reflected light at the address area of the disk, which is a drawback of the conventional device, and to perform a stable and accurate jumping search. The purpose of the present invention is to provide a jumping search device.

Structure of the Invention In order to eliminate the drawbacks of the conventional device, the present invention disables jumping operation near the address section along the track direction.
L intervals are provided, and the jumping operation is not performed in the interval where the jumping operation is affected by the address section.

Description of examples Embodiments of the present invention will be described in detail using the drawings.

FIG. 4 shows an embodiment of the present invention.

In the figure, parts similar to those in Figure 1 are given the same numbers.
'The explanation will be omitted.

In this embodiment, in order to eliminate instability in the jumping operation caused by changes in the amount of light reflected from the address section 21, the jumping operation is started so that the light beam is not located on the address section 21 immediately after the end of the deceleration pulse. A prohibition period setting circuit 22 that does not generate a jumping prohibition signal that prohibits the jump is provided, and is configured to gate the jumping start instruction signal output from the jumping start instruction circuit 17.

More specifically, in this embodiment, in place of the disk 7 described above, a disk 25 is used in which the following points are newly added to the disk 7.

As shown in FIG. 5, the disk 25 is provided with an address mark 26 indicated by diagonal lines in FIG. 5 immediately before the address section 21. As shown in FIG.

When the disk is rotated in a predetermined rotational direction 27, an address portion 26 is placed immediately after the address mark 26.
1 is present, and is composed of a concave-convex structure bit string, and the bits are arranged in a fixed number M in a single period T1 so that it can be immediately recognized by the change in the amount of reflected light that the light beam has passed over the address mark 26. Individuals exist.

The disk 26 is used in exactly the same way as the disk 7, but the sum signal from the two-part photodetector 8 output from the synthesis circuit 14 is input to the address mark detection circuit 24.

The address mark detection circuit detects that the sum signal changes in the single period T or M-a times (M-a), and the light beam passes through the address mark 26 and immediately before the address section 21. It detects that it is located at , and outputs an address detection signal to the inhibition period setting circuit 22.

Upon receiving the address detection signal, the prohibition period setting circuit 22 outputs a jumping prohibition signal number to the gate circuit 23 during the period when the light beam is located on the address section 31 immediately after the end of the deceleration pulse during the jumping operation when a jumping operation is performed. Jumping starts are prohibited.

As described in the description of the conventional example, one address section 21 is provided for each track, so the light beam is positioned on the address section 21 at every rotation period T2 of the disk 26.

Therefore, upon receiving the address detection signal, the inhibit period setting circuit 22 sets the jumping inhibit signal to LOW for a period of width W3 after a predetermined delay time W2.

The time widths W and W3 are such that if the jumping operation is started after detecting that the light beam is on the address section 21, the disk 25 will rotate once and when the light beam is located on the address section 21 again, the jumping operation will start. The setting is such that the start of the jumping operation is prohibited during the period when the brake pulse ends.

On the other hand, the jumping start instruction signal output from the jumping start instruction circuit 17 is passed through the gate circuit 23 to the jumping signal generation circuit 18 and the switch control circuit 1.
9 is input.

The gate circuit 23 transmits the jumping start instruction signal as it is to the jumping signal generation circuit 18 and the switch control circuit 19 when the jumping prohibition signal is HIGH (-1), but always outputs LOW when the jumping prohibition signal is LOW. do.

Therefore, even if the jumping inhibit signal is HIGH, that is, even if the jumping operation is started, the light beam will not reach the address section 2 immediately after the deceleration pulse ends during the jumping period.
Since the jumping star [instruction signal is transmitted to the jumping signal generation circuit 18 and the switch control circuit 19 only during the period when the jumping star is not located on It will never be stable.

In this embodiment, one address mark 26 and one address section 21 are provided on each track, and after the address mark 26 is detected and the disk 25 rotates once, the light beam is directed to the same address section 21 again. , we set a jumping prohibition period that prohibits the start of the jumping operation immediately after the end of the deceleration pulse during the jumping operation, but if there are multiple address parts in each track, a certain address mark is detected. Then, the light beam applies a jumping prohibition period to the address section located next to the address section located immediately after the address mark, so as to prohibit the jumping operation at the timing immediately after the end of the deceleration pulse during the jumping operation. A similar effect can be obtained by providing this.

In addition, in the above, a jumping prohibition period was provided immediately after the end of the deceleration pulse during the jumping operation period to prevent the jumping operation from becoming unstable due to the influence of the address section, but the light beam is positioned at the address section immediately before the jumping operation. It goes without saying that a similar effect can be obtained by providing a jumping prohibition section immediately after the address section until the tracking control error caused by the address section is eliminated in order to prevent instability in the jumping operation caused by the address section. do not have.

In this embodiment, the timing for generating the jumping prohibition signal is generated by detecting the alarm 26.
As shown in FIG. 6, a disk 29 provided on an index mark 28 in a non-track area may be used to detect the index mark 28 and generate the timing for generating the jumping prohibition signal.

Similarly, the position of the address mark 26 or index mark 28 may be stored, and the timing for generating the jumping prohibition signal may be generated using the stored signal.

By establishing a no-jumping section, which exceeds the effects of the invention,
It is possible to prevent instability of the jumping operation caused by changes in the amount of light reflected from the address area of the disk, and its practical effects are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a configuration example of a conventional tracking control and track search device, FIG. 2 is a plan view of a twister, FIG. 3 is an enlarged view of a portion of FIG. A block diagram showing the configuration of a tracking control and track search device showing an embodiment, FIG. 5 is a plan view of a disk used in the tracking control and track search device shown in FIG. 4, and FIG. 6 is a plan view of a disk having index marks. It is a diagram. 1... Semiconductor laser, 5... Converging lens, 7... Disk, 8... Photodetector, 9...
・Differential amplifier, 10... Phase compensation circuit, 11.
... Switch, 12... Drive circuit, 13...
...Tracking element, 14...Synthesizing circuit, 1
6...Jumping direction indicating circuit, 17...
・Jumping start instruction circuit, 18...Jumping signal generation circuit, 19...Switch control circuit, 21...Address section, 22...Prohibition period setting circuit, 23... ...Gate circuit, 24--
...address mark detection circuit, 25....disk, 26....address mark, 28....
index mark. Name of agent: Patent attorney Toshio Nakao and one other person (Figure 2, Figure 3, Figure 5)

Claims (4)

[Claims] (1) It has a track on which a signal is recorded or is formed of unevenness for recording a signal, and the track has an address part that identifies the track or identifies a specific signal block on the track. a converging means for converging and irradiating a light beam generated from a light source onto an optically recordable/reproducible record carrier surface in a substantially predetermined convergent state; a driving means for moving in a direction parallel to the surface of the record carrier; a detecting means for detecting the positional relationship between the light beam in a predetermined converged state by the converging means and the track; tracking control means for driving the driving means so that the light beam in a predetermined convergence state by the means is substantially always on the track; 1. A track search device comprising: a jumping means for performing a jumping motion of moving to a track; and a jumping prohibition means for inhibiting the jumping motion for a predetermined period. (2) The record carrier has an address mark formed of unevenness indicating the start of an address section, and the jumping inhibiting means has an address mark detecting means for detecting the address mark, and the jumping inhibiting means has an address mark detecting means for detecting the address mark. 2. The track search device according to claim 1, wherein said jumping operation is prohibited by detecting a mark. (3) The means for inhibiting jumping is during jumping operation.
3. The track search device according to claim 2, wherein a jumping operation is prohibited at a timing when the light beam is positioned on the address section. (4) The track search device according to claim 2, wherein the jumping inhibiting means inhibits the jumping operation for a predetermined period immediately after the light beam is positioned on the address section.