JPH02165425A - Multiple optical head control system - Google Patents

Abstract

PURPOSE:To improve an access speed by providing the processor to be exclusively used on each of plural optical heads and independently controlling the LDON/ OFF of the optical head, focus withdrawing and track withdrawing in accordance with the instructions from a host device. CONSTITUTION:A head control circuit 2-1 controls the optical head 1 in accordance with the instruction from the processor 2 and a drive control circuit 3-1 makes various kinds of control. The optical heads 1 are provided by each piece on both surfaces of a medium so that both the surfaces can be accessed even if the front and rear surfaces of the medium are not alternated. The processors 2 to be exclusively used are respectively provided on these optical heads 1 to control the laser (LD) ON (writing current regulation, reading current regulation, etc.), focus withdrawing and track withdrawing in parallel. The control of seeking, etc., is rapidly executed in this way.

Description

[Detailed Description of the Invention] [Summary] Regarding a multi-optical head control method for controlling a plurality of optical heads, the present invention proposes that a dedicated processor is provided for each of the plurality of optical heads to perform parallel control and improve access speed. As a general rule, a plurality of optical heads mounted on a carriage on one side or both sides of the medium and L
DON10FF control, focus servo control and trunk servo control? 21), and instructs these processors to perform 7.1?1 independently for each optical head.
).

[Industrial application field]

The present invention relates to a multi-optical head control method for controlling a plurality of optical heads.

(Prior Art and Problems to be Solved by the Invention) Conventionally, in order to increase the access speed, a t2 device using a plurality of heads has been devised.

However, in the case of an optical disk device, a sequence such as turning on the laser and pulling the focus is required before tracking. For this reason, when one microprocessor controls these multiple optical heads, it takes time to process these sequences, and
LD control even if the optical head is not selected,
Since the focus servo must remain on and control cannot be stopped, as the number of optical heads increases, the load on the microprocessor increases, the complexity of control increases, and the response speed decreases. There was a problem.

The present invention aims to improve access speed by providing a dedicated processor for each of a plurality of optical heads and controlling them in parallel.

[Means to solve problems]

FIG. 1 shows a basic configuration diagram of the present invention.

In FIG. 1, an optical head 1 is a plurality of optical heads mounted on a carriage, and is used to write data onto a medium and optically read data from the medium.

The processor 2 controls the optical head 1 (1t(LDONOF
F, control of focus pull-in, trunk pull-in, etc.).

[Effect]

As shown in FIG. 1, in the present invention, a plurality of optical heads 1 are mounted on a carriage on one or both sides of a medium, and each of these optical heads 1 is controlled by a dedicated processor 2 (LD
control such as ON/OFF, focus pull-in, track pull-in, etc.).

Therefore, in response to a seek instruction from the host device 4,
A processor 2 dedicated to the optical head 1 executes controls such as LDON/OFF of the optical head 1, 7 orcus pull-in, and track pull-in in parallel.
The processor is not overloaded and control can be performed quickly in parallel.

〔Example〕

First, the principle structure of the present invention will be explained using FIG.

FIG. 1(a) shows a configuration in which one optical head 1 is provided on both sides of the medium. This makes it possible to access both sides without having to interchange the front and back sides of the medium. , a dedicated processor 2 is provided for each of these lights, and the laser (LD) is turned on (adjusting the current for reading, adjusting the reading current, etc.), and the focus is pulled in (the fifth
By controlling in parallel track pull-in (see Figure 6), track pull-in (see Figure 6), seek and other controls can be performed quickly.

FIG. 1(b) shows a configuration in which one optical head 1 is provided on the inner side and one on the inner side of one side of the medium.This allows the movement distance z of the optical head 1 to access the medium.
1 is reduced by half, and a dedicated processor 2 is provided for each of these optical heads l to perform laser ON (write current adjustment, read current adjustment, etc.), focus pull-in (see Figure 5), and track pull-in (see Figure 6). )
By controlling n in parallel, it is possible to improve the seek speed and the like.

The head control in circuit 2-1 in FIG. 1 is a circuit that controls the optical head 1 in response to instructions from the processor 2. The drive control circuit 3-1 performs various controls. The host device r14 is a host that accesses the medium. The SP motor rotates the medium. Further, the plurality of optical heads 1 are mounted on a single carriage (not shown) and are moved roughly.

FIG. 2 shows a detailed configuration diagram of the configuration shown in FIG. 1(A), that is, a configuration in which one optical head 1 is provided on both sides of the medium.

In FIG. 2, a light beam L is a laser beam emitting L.
D (laser diode), collimating lens that converges the emitted light, BS (beam splitter), OL (objective lens) that focuses the laser light onto the medium, and OL (objective lens) that moves the OL closer to or away from the medium and in the radial direction (track) of the medium. It consists of an actuator that moves the light in the vertical direction) and a detector that detects the light reflected from the medium. This optical head l has the same one on both sides of the medium.
tE 5M is placed on one carriage (not shown). The medium is rotated at a predetermined speed by the SP momo.

The head control circuit 2-1 includes an LD (
LD that performs 0N10FF (laser diode), write current adjustment, read current adjustment, etc. tJI <n A circuit 5, a focus servo control circuit 6 that controls an actuator that moves the OL (objective lens) constituting the optical head 1 toward or away from the medium, and a focus servo control circuit 6 that controls the optical head 1 in the radial direction of the medium (track and direction). It is composed of a trunk servo control circuit 7, etc., which controls an actuator that moves the trunk in the right angle direction.

Processor 3 issues a command (laser O) to processor 2.
N, focus ON, rack ON, etc.). After receiving these instructions, the processor 2
Instructs the control circuit 5, focus servo control circuit 6, and trunk servo control circuit 7 to perform predetermined control? I try to do 1).

The AGC amplifier (automatic gain control amplifier) 8 is an amplifier that amplifies the signal detected by the detector to a predetermined amplitude.

The waveform shaping circuit 9 is a circuit that shapes six waveforms.

The data separator E0 separates DA"l'AC data) and CLOCK from No. 13 whose waveform has been shaped by the waveform shaping circuit 9.

The decoder 1) detects the current track position based on the data and clock input from the data separator 10.

Next, the operation of the configuration shown in FIG. 2 will be explained using the time chart shown in FIG. 3 (a).

In FIG. 3(A), ■ indicates processor t.

(Processor 3 in FIG. 2) notifies processor t1 and processor 1g (processor 2) of a command to turn on the laser.

■ is the processor that received the laser-on command in ■, processor 2. turns on the laser, this laser O
N turns on the LD (laser) and reads 1'? The voltage applied to the LD is adjusted so that the EAD (or WRITE) current flows.

■ is processor 0, processor. ■LD luminescence! l
! Processor 8.1m is completed. Notify.

■ Processor tx sends a focus-on instruction to processor □ and processor. Notify.

■ is the processor that received the focus-on command in ■,
1. The processor, t, performs focus retraction. This focus retraction is detected while moving the distance between the OL and the medium by moving the actuator shown in Fig. 2 &In by the divided detector as shown in Fig. 5 (b). Each signal (a
, b, c, d) to perform graphical calculations and focus
Find the Error signal.

Then, as shown in Figure 5 (a), this FocusE
With the rror signal as the Y axis and the distance between the OL and the medium as the X axis, find the focus position of the zero error that is indicated by a black circle in the figure, which is closer to the medium, and then move the focus position before and after to obtain the track signal. The maximum focus position is determined as the focus pull-in position, and is held at this position thereafter; t+lIm.

■It's a processor 3, a processor! ■The processor indicates that focus retraction has ended. to notify.

■ Power the processor (trunk-on instructions).

Losefusa! 1 and the processor.

■ is the processor 1 that received the trunk-on command at ■.
, Processor:1 performs trunk retraction.

As shown in FIG. 6, this track pull-in is controlled so that the pull-in is performed at the point of the track error signal marked with a black circle in the figure.

■ is processor 8, processor 2! ■ The processor indicates that track retraction has finished. Notify.

[Phase] notifies the host device 4 that the processor tx is ready. Then, the host device 4 issues the NOK command shown in FIG. 4, and further issues a READ or W+1)T2 command,
Access media.

(2) Holds the track with the trunk retracted in (2) For example, in the case of a spiral trunk, the medium kinks back (returns to the original trunk) every time it rotates.

As mentioned above, there is a dedicated processor for each Hikari Radar! By independently controlling the laser ON, focus pull-in, and track pull-in of each optical head l, it is possible to quickly control the optical head 1, and the processors are the same. This program is good (and simple).

FIG. 3(b) is an explanatory diagram of the operation of the configuration of FIG. 1(b), and is a diagram illustrating the processor of FIG. 2. 3 and the control j′n of this processor! The operation of the configuration shown in FIG. 3(B), which is an explanatory diagram of the operation of the configuration in which the burden is placed on the processor 12, is the same as that of FIG. 3(B), except that the number of processors is reduced by one.

FIG. 4 shows an example of a time chart during seek.

In FIG. 4, ■ indicates that the host device 4 processes the seek command. Issued on 3rd.

0 is processor 2. Processor 1. is in on-track state. The trunk off command is notified to the

In (2), the processor 21, which has been notified of the trunk-off command in (2), controls the optical hand l to off-trunk, and then notifies the processor that off-track control has been completed.

■ is processor 2. moves the carriage to the approximate 1-rack position corresponding to the seek command.

■Processor, 2 corresponds to the track-on command! We will notify you as soon as possible.

In [phase], the processor performs track pull-in.

(2) notifies the processor that processor 2 has finished track pull-in.

[Phase] is processor 8. confirms the address of the current trunk to which the truck has pulled in at [phase].

◎ indicates processor 2. calculates the difference between the current track confirmed in [phase] and the trunk (address) specified by the seek command in (3), and notifies the processor of a jump command corresponding to this difference.

[Phase] causes processor 2 to jump by the notified trunk.

[Phase] notifies the processor that the jump of [Phase] has ended.

■ is processor 2. checks the address of the current trunk and the trunk specified by the seek command (■).

(2) notifies the host device 4 that the series of seek instructions has been completed when the address (2) is confirmed.

In response to this, the host device 4 issues a READ command or a WI? An ITE command is issued to access it.

■ Keep the processor in the on-trunk state.

As described above, in response to the issuance of a seek command from the host device 4, off-track control is performed by the processor 21 and processor 2□, which are provided exclusively for the optical head l, and the rough It is possible to seek to a desired track by J control for shifting, further by 1 to rack pull-in control and track jump control by the processor.

〔Effect of the invention〕

As explained above, according to the present invention, in response to the issuance of a seek command from the host device 4, the processor 2 provided exclusively for each optical head l
Since it adopts a configuration in which controls such as DON/OFF, focus pull-in, trunk pull-in, etc. are executed independently, the processor control is not overloaded, and parallel side jII is possible, allowing seek control etc. to be performed quickly. can be executed.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the principle of the present invention, Figure 2 is a diagram showing the configuration of one embodiment of the present invention, Figure 3 is a time chart of the present invention, Figure 4 is an example of a time chart during seek, and Figure 5 is a focus diagram. Drawing explanatory diagram, FIG. 6 shows an explanatory diagram of truck pulling in. In the figure, 1 is an optical head, 2.3 is a processor, 2-1 is a head control circuit, 4 is an upper bag π, 5 is an LD control circuit, 6 is a focus servo control circuit, and 7 is a track servo control circuit.

Claims (1)

[Claims] In a multi-optical head control system for controlling a plurality of optical heads, a plurality of optical heads (1) mounted on a carriage on one side or both sides of a medium, and corresponding to these plurality of optical heads (1) are provided. Add, LDON/
A multi-purpose optical system comprising a processor (2) that performs OFF control, focus servo control, and track servo control, and configured to instruct these processors (2) to independently control each optical head (1). Optical head control method.