JPS61187131A - Optical disk device - Google Patents

Abstract

PURPOSE:To make high speed access stably by bisecting a photodetector to detect displacement of a lens in the direction at right angles to the track, sampling the difference of detected output only in the part of a mirror and making negative feedback to the displacement of the lens. CONSTITUTION:A photodetector 7 is bisected to detect displacement of a lens in the direction at right angles to the track of an optical disk, and the output that passed through an adder 8 is inputted to a peak detecting circuit 10. On the other hand, the output passed through a differential amplifier 9 is given to a sample and hold circuit 11. The timing of sampling is made by peak part of the adder 8 in the circuit 11, and the sampling is made in the mirror part between bits of the optical disk. The sampled output is used to make negative feedback to lens displacement through an LPF12. Thus, the access can be made with high accuracy, stably and at high speed.

Description

[Detailed Description of the Invention] [General Field of the Invention] The present invention is directed to the access method of the original pick-up of the original disc Niyu-sho (%'), which is suitable for high-speed access without low movement of the lens when moving the pick-up to the load. *71: Regarding access method.

[Back mold of invention]

As the original spot footing device for the original disc playback dAIt,
In order to focus the objective lens on the disk, it is said that it must be driven in the 7 orcus direction (9 directions) and in the tracking direction (i: direction perpendicular to the disk) to follow the track of the disk. . In the Motohitsukatsu 1 device using such a two-way pair-cutting lens body scissors 1τ.

If you move the pickup halfway in the forward direction and have no access), this mark will cut the tracking control, so the sword lens will move in the direction of the track.

Even if the objective lens is shielded by a stone, the tracking pull-in 1tIJ operation is unstable.
The disadvantage is that it is difficult to retract and it takes time to access, and it is difficult to know where to retract it within the trunking range of the lens.In other words, it is difficult to retract it at the same place as the center of the original pick amp and the center of the objective lens. Because I don't sleep.

There were 5 drawbacks due to the Vcl, which caused the pickup's transfer voltage to be distorted over 4 minutes.

As a solution to the problem of upper Bb, there is a method of attaching a hZIK detection sensor to the lens actuator and controlling it so that the lens does not move during access (when moving the pickup).
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[Purpose of the invention]

The purpose of the present invention is to improve the access method of the tracking direction of the lens that occurs when the lens moves (1g), that is, to add a tilt angle to the lens actuator, and to adapt the lens f-direction. The objective is to provide an optical disc #C direct.

In the case of the racking method (inventive type), the i-beam moves in a direction perpendicular to the original axis on the photodetector as the lens moves. *The sweetness of the tracking system, which is called the @needle method (butshuful method), etc., is that the movement of the original beam on the optical transmitter carried by the upper Hc is the offset of Yokohitsukuda and C
9. Tracking? It is known that there is a large encampment of 5 m and 1 go along Cape 1rlJ. The present invention is.

In the case of a method in which the optical inertia is not placed at the conjugate point of the luck of the disk,
In other words, in the general pickup method in which the reflected light beam from the disk is not used by comparing it on the detector, the optical transverse ratio is divided at least parallel to the information track and one reconstruction transverse ratio is used. Is it possible to carefully adjust the position of the lens by using the 5-beam movement to displace the lens in the tracking direction? : It is to be imitated.

[Results of the invention] 1 Below 1 Examples of optical system for actualizing the present invention
). The laser source that exited laser diode 1 is 8-7.
1 rhythm 2. Go back through the collimator lens 3 and move the objective lens 4
A black dot is connected to the ft1t track on the disk 5. The laser beam reflected by this disk 5 is returned to the objective lens 4. The light passes through the collimator lens 3, is reflected by the 8-71 rhythm 2, and enters the photodetector 7 via the cylindrical lens 6. The photodetector 7 is divided into 4 parts, 5 to 7d, as shown in Figure 1 (CB), and the focus configuration 100 is divided into 5 to 7 parts as shown in (7α+7C) - (7b+7tt).
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Here, when the objective lens 4 moves KW in the direction of the arrow, the light beam on the photodetector 7 will be distorted as shown by 4iltS. Therefore, the movement of the spot on the detector Z
By comparing horizontally.

Conversely, movement of the objective lens 4 due to disturbance can be suppressed.

Next, the present invention will be described in detail using Figure 2, which is an example of a circular gummy diagram, and Figure 3, which is a circular gummy diagram.

Nine detectors 7'a' track and lens change in direction 1i2
Divide : into 2 parts by width ratio of 5 (i.e. 7α+76)
The output of the 1-element calculator 7 passes through an adder 8.

From terminal 14, Wang Jing-# (i.e. 7α 17b 170+7
d-) is guided to the signal processing circuit (not shown).-
The output of the width ratio device 7 is the difference mm width ratio device 9fjr, m when IW1.
(C7a+74)-C7c+7ct)
is asked by the f7 full small field circuit 11. Here, the sampling timing of the sample and hold circuit 11 is performed based on the +beak addition of the output of the nasal atomizer 8. The output of the sample 1 hold circuit 11 is passed through the low pass filter 12 at 49
．． The signal goes back through the servo circuit from the fl1M element 13 and is supplied to the actuator that drives the objective lens.

Next, the output shaping of the valley block ta: Use and master the fifth
Incidentally, (α) is the output shape of 600 million when the light spot softened by the objective lens cuts the track to the right when the objective lens 4 is on the original axis.

Also, (+6) is a state in which the original beam is centered on the detector as shown in Figure 1 CB), that is, a state in which the objective lens 4 is deviated from the center of the original axis and the original spot is on the track? Shows various output shapes when reconnaissance cutting. The output shaping A of the 7JQ calculator 8 is 1:5Z for each pit of the disk track, and the light emitting type is changed to 4, AH. At this time, the upper side is between the pits, and the lower side is the pit portion. On the other hand, the output shaping of the differential stage rr+ device 9 becomes B, B, and so on. In other words, in (αJ and ψ), shaping is the key. In other words, when the objective lens is aligned with the original axis, the original spot is at the center of the nine-side output device, so when it is located above the formation of A, that is, near the pit and the darkness between the pits, the output is aha. . However, in the state where the opening lens of 61 is in the position, it is unilateral on one side on the 1st horizontal ratio 7 (i.e. the 15th JCB), so AH
I'm waiting for off-seratra which is at +beak point. Since this offset is proportional to the displacement of the cutting lens, it is convenient to use this offset. For this reason, it is only necessary to sample the output of the aMJJ stage width device 9 at the upper side of the A waveform.

Therefore, the timing output of the +beak part of the shaping of A1 and AH is 1 * Sampling is performed with C1, and the outputs of the a-bass filter 12 are Dl, D, and 5, respectively. The state where the lens is entering (
Offset can be extracted with bl.

The lens can be braked by applying this output to the lens actuator and creating a negative output.

(Effect of -A light) As described above, the effect of the light effect of Δ1 in 5 is that the lens actuator does not have the force of the lens position sensor, and the circuit (ICi According to Mr. O, by making 8 powerful parts (without any parts),
The lens tracking IBJ, which starts when the toe 9 tracking servo is turned off when the original big heat 1 moves when accessing, etc., is now fixed at the center of the light flux of the original lens. N! Because I *m returned Ruu 1.

Habona (Chokotoka made, easy access.

Stabilization, Sho Tohoku becomes 9 匪.

[Brief explanation of the drawing]

Fig. 1 (/f) is the origin of the wish of the central example of the present invention, Fig. 1 (CB) is a configuration diagram of the receiving part of the light detection 6, Fig. 2 is a circuit diagram, Fig. 3 is the horizontal ratio and the calculated 6-shin or he-gata-ku. 1... Laser diode 2... 8-71 rhythm 3.
... Collimating lens 4 ... Objective lens 5 ... Disc 6 ... Cylindrical lens 7 ... Original horizontal ratio 8 -
... Kataro: J! l: Container 9...Nose device 1
o...Beak habituation circuit 11...Sun 1 ring times m1
2...a-Bass filter 1 q (A>
(8912 Figure 3 (a) (b)
) Procedural amendment (voluntary)

Claims (1)

[Claims] 1. A beam from a laser light source is focused by an objective lens and irradiated onto an optical recording medium, and a reflected beam from the optical recording medium is irradiated onto a photodetector to obtain a reproduced signal. In the optical disc device, the photodetector is a photoelectric conversion element divided into two in a direction perpendicular to the track of the optical recording medium, and means for obtaining a difference in detection output of each of the photoelectric conversion elements. and a means for detecting the position of the objective lens in a direction perpendicular to the track, and furthermore, the means detects the position of the objective lens in the direction perpendicular to the track, and the means detects the position of the objective lens in the optical system of the optical disc device when the tracking servo is off due to disturbance or the like. What is claimed is: 1. An optical disk device characterized in that a negative feedback loop is configured such that the optical disk is located at the center of the optical axis of the optical disk device. 2. The optical disc device according to claim 1, characterized in that the difference in detection output of each of the photoelectric conversion elements is sampled only between pits of the optical recording medium, that is, in a mirror portion. Optical disk device. 3. In the optical disc device according to claim 1 or 2, two directions of focus direction and tracking direction are provided.
An optical disc device comprising a dimensional objective lens driving device.