JPS5864644A - Optical disk search control system - Google Patents

Abstract

PURPOSE:To suppress the unbalanced amount of a kick by making kick pulses, which move an optical pickup during search, different in peak value and pulse width according to the direction of the pickup, i.e. forward and backward directions. CONSTITUTION:An optical pickup 2 is controlled by a radial error signal detector 4 without any deviation from a balancing point. A reproduced address detected by a digital demodulator 8 is compared at a part (10) with a set value 9, and a circuit 11 generates a positive or negative kick pulse according to the result of the comparison, thereby driving the optical pickup 2. Since the optical pickup 2 is moded in a radius direction by a feed motor 3, the kick pulses generated by the kick pulse generator 11 have different waveforms in the direction FWD and RWD to suppress the unbalanced amount of movement.

Description

[Detailed description of the invention] The present invention relates to an optical disc search control system.

Optical pickups used in optical disk devices, etc.
It has a moving mechanism consisting of a feed screw and a feed motor so that the entire disk can be moved in the radial direction of the disk. This movement mechanism allows the pickup to be displaced to any information track. On the other hand, methods have been considered to provide a pulsed kick signal to a tracking servo system, which is normally included in rounding and optical pickups, to enable the pickup to be displaced more easily.

In other words, the tracking servo system has a deflection means that detects the deviation of the optical beam in the radial direction of the disk and deflects the optical beam in the radial direction accordingly so that the optical beam accurately traces the information track on the disk. Therefore, the method is to apply a medium hit signal to this deflection means to force the light beam to fly multiple times.

To search using this method, that is, to displace the pickup to the information track having the target address, apply kick No. 16 to the tracking servo system to skip the track, and then continue the address and move the next track suitable for the target address. [by repeating until], it is achieved.

By the way, the time it takes to complete the address after giving the kick signal depends on the mechanical response of the pickup, the responsiveness of the nervo system, etc. For example, if 100 m and 84 degrees are required, and the disc rotation speed is 500 rpm to 200 rpm, it will vary depending on the responsiveness of the data playback system.
The disk makes one to a half revolution in 0m8.

Therefore, if the pickup is turned in the FWD direction (direction along the information recording order), the pickup will be displaced ahead of the track corresponding to the key YJP signal at the time of writing the address. , 9BWL) direction (in the opposite direction to the information writing order), if the address is 11
At the time when four is dead, the bit-up is displaced in the direction of decreasing the number of skip nine tracks corresponding to the kick signal.

In other words, even if the same kick signal is given, the actual kick amount will vary depending on the direction of the kick, and as a result, the search time will become longer depending on the direction of the search. .

An object of the present invention is to solve the above problems and provide a dimensional disk search control method.

The present invention is characterized in that the peak value or pulse width of the kick pulse is made different in the FWD direction and the BWD direction.

FIG. 1 shows an embodiment of the present invention. In the figure, 1 is a rotating disk on which an information track is formed in a spiral shape and information including addresses is recorded, 2 is an optical pickup that reads the information on disk 1, and 3 is a circular disk that moves the pickup 2 in the radial direction of the disk 10. 4 is a radial error signal detector that detects the deviation of the original beam from the equilibrium point (in the disk radial direction) from the signal obtained from the pickup 2 and outputs an error signal; 5 is a radial error signal detector that outputs an error signal; and 6 is a radial drive coil for deflecting the light beam in the radial direction.

9, 8 is a digital demodulator for demodulating the address signal read out by the pickup 2; 9 is a register in which the search address is set; and 10 is a comparison for determining the polarity of the difference between the reproduced address and the search address. The reference numeral 11 is a middle pulse generation circuit which generates a middle pulse of positive and negative polarity in accordance with the output of the comparator, and the reference numeral 12 is a driver 41 circuit for driving the feed motor 3.

Now, when a search address is set in register 9 along with a search command (not shown), comparison circuit 10 selects pickup 2. It compares it with the address found through the demodulator 8 and outputs a signal indicating whether the difference is positive or negative. As a result, the medium ivy pulse generator 11 generates a medium ivy pulse corresponding to this polarity. This kick pulse is added to the first difference signal from the detection 114 and the ner is one path S.
K is supplied, so that the light and one meter 2m are +y.

As shown in Fig. 2, after applying a kick pulse, a period of time for starting the playback address of pickup 2 is secured,
If the playback address does not match the search address, the pickup is gradually displaced to the information track corresponding to the search address by repeatedly generating a middle pick pulse.

In this period of d, if the reproduction address is now the search address, the comparator circuit 10 outputs a positive polarity signal. At this time, the direction to kick is the FWD direction. On the other hand, if reproduction address>search address, comparison circuit 10 outputs a negative polarity signal. At this time, the kicking direction is the HWD direction.

The kick pulse generating circuit 11 outputs a kick pulse of positive polarity when a positive polarity signal is input, and outputs a negative kick pulse when a negative polarity signal is input. In this case, by setting the peak value of the positive kick pulse to be lower than the peak value of the negative middle kick pulse, the imbalance in kick amount is eliminated.

In addition, in the above embodiment, FWD hard pulse WI)
The peak value is different depending on the pulse.

It is also possible to increase the pulse width of the intermediate pulse for FWD as well as the hard pulse for BWD.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of the present invention, and FIGS. 2 and 3 are rounded diagrams illustrating its operation. l...Disc 2...Bitter up 3...Feed motor 6...Radial drive coil 11...
... Kick pulse generation circuit expert Patent attorney Odori
Kensuke Chika (and 1 other person) ±01

Claims (1)

[Claims] A light beam is irradiated onto a rotating disk on which information including address f: is recorded on a substantially concentric information track, and the # information track is irradiated with a light beam to read the information, and the deviation of the light beam in the disk radial direction is indicated. In an optical disk device having an optical pickup that performs tracking by detecting an fA difference signal and driving a deflection means that deflects the light beam according to the first difference signal, the light beam tracks a plurality of information tracks. a kick pulse generation circuit that generates a kick pulse that causes the object to fly and supplies it to the deflection means; and a kick pulse generating circuit that uses the kick pulse to reproduce the address of the information track to which the information track is to fly, and to search with this reproduction address. the kick pulse generation surface generates kick pulses of different polarities depending on the comparison result by the comparison means, and the waveform of the middle pulse of one polarity is different from that of the other polarity. An optical disc search control method characterized by a waveform different from that of the kick pulse.