CN1360719A - Optical disk reproducing device - Google Patents

Abstract

The objective is to provide an optical disc playback device that eliminates the need for CLV re-introduction even when the optical head deviates from focus, reducing disc rotation waiting time, shortening search time to the inner and outer circumferences, enabling stable control, and reducing spin-up acceleration time. The spindle motor control during the entire process from spin-up acceleration to standby mode is set to CAV control (constant angular velocity control).

Description

disc playback device

technical field

The present invention relates to an optical disc playback device (International Patent Classification G11B 7/00), and in particular to a method of using CAV control (constant angular velocity control) to process the rotation speed-up of the optical disc playback device and the rotation control method of the spindle motor when the optical disc rotates at a low speed.

Background technique

The structure of this kind of optical disc playback device is shown in FIG. 2 .

The optical disc 1 is rotationally driven by a spindle motor 2 . The optical head 3 for reading information from the optical disc 1 is driven by a traverse motor 4 in the radial direction of the optical disc 1 .

An output signal from the optical head 3 is input to a DSP (Digital Signal Processor) 5 via an amplifier 4 . The DSP 5 controls the focus of the optical head 3 through the actuator driver 6 to make the focus of the optical head 3 more appropriate. Furthermore, the DSP 5 controls both the motors 2 and 4 through the main shaft and traverse driver 7 so that the drive of the spindle motor 2 and the drive of the traverse motor 4 are appropriate.

The CPU 8 is a central processing unit that operates according to a control program and sends instructions to cause the DSP 5 to execute target processing. ECC&I/F9 has ECC (Error Correction) function and interface function, and is a device that manages communication with the host computer. The DRAM 10 is a memory for temporarily storing read data. 11 shows the system control processing unit.

However, it is generally adopted that information is recorded at the same density on the entire surface of the optical disc from the inner periphery to the outer periphery. In an optical disc playback device for reproducing such an optical disc, it is generally known that the rotation control of the spindle motor in the rotation speed-up process is performed by CLV control (constant linear velocity control) in which the rotational speed is changed according to the radial position of the optical head, A way to keep the length of the track read by the optical head constant per unit time.

FIG. 3 shows a flowchart of the processing in this regard.

In step S1, the spindle motor 2 is set to work at a constant linear speed with CLV control. In step S2, servo adjustment is performed. In step S3, the final lead-in (LEAD-IN) address is obtained. Where , CLV determinations are performed under CLV control.

In step S5, the spindle motor 2 is switched from CLV control to CAV control, and is controlled so that the angular velocity is constant.

In step S6, the angular speed is switched to 1/2 speed of the maximum rotation speed (12 times speed if the maximum is 24 times speed).

In step S7, reading of TOC (Table of Contents), which is index information of the disc, is performed.

In step S8, SUB-Q (additional information for making data with advanced functions) less than 00:02.00 is acquired.

In step S9, the head (HEADER) difference is obtained according to the SUB-Q of step S8, and the read-in setting (READ SET) is executed.

In step S10, the speed switched in step S6 is returned to the original state, and a hold track (HOLD TRACK) is performed.

Like this, in the case of carrying out the processing up to the read standby state by CLV control (constant linear velocity control), because the rotational speed of the inner and outer periphery changes with the position of the optical head, it is necessary to always monitor the data recorded on the optical disc.

Therefore, when the focus or tracking deviates, the current rotation speed is unknown, and the rotation speed of the disc must be reduced to reintroduce the CLV. As a result, the rotation speed-up time is prolonged.

disclosure of invention

The object of the present invention is to provide an optical disk reproducing apparatus which does not need to reintroduce the CLV even when the focus of the optical head is out of focus. In addition, the waiting time for the rotation of the optical disk is small, and the seek time to the inner and outer circumferences is shortened. Stable control can be performed, and the rotation acceleration time can be shortened.

In order to solve this problem, the optical disc playback device of the present invention classifies the processing up to the reading standby state in detail, and performs all the processing by CAV control (constant angular velocity control).

With this configuration, even when the focus of the optical head is off, there is no need to change the rotation speed, so it is not necessary to reduce the rotation speed of the optical disk to perform the CLV reintroduction operation as in the case of CLV control. In addition, because the rotation waiting time of the optical disk is reduced , so the search time to the inner and outer circumference is shortened, stable control can be performed, and the rotation acceleration time can be shortened.

The optical disc reproducing device described in claim 1 of the present invention is an optical disc reproducing device for reproducing a disc-shaped recording medium recorded at a constant linear velocity, wherein the CAV control (constant angular velocity control) is used for the optical disc reproducing device. The spindle motor in processing is controlled from the start of the rotation speed-up processing to the reading standby state.

According to the structure of the present invention, even if the focus or tracking of the optical head deviates, it is not necessary to reduce the rotation speed of the optical disc to reintroduce the CLV. The search time is shortened and stable control can be performed.

In the optical disc reproducing apparatus described in claim 2 of the present invention, in claim 2, the spindle motor is controlled by CAV control (constant angular velocity control) during the low-speed rotation control process of the disc-shaped recording medium.

A brief description of the drawings

FIG. 1 is a flow chart showing the rotation speed-up control processing in the optical disk reproducing apparatus of the present invention.

Fig. 2 is a general configuration diagram of an optical disc playback device.

Fig. 3 is a general flow chart showing rotation speed-up control processing in the optical disk playback apparatus.

Implementation form

An embodiment of the present invention will be described below with reference to FIG. 1 .

In addition, since the configuration itself of the hardware is the same as that of FIG. 2 showing the conventional example, it will be described with the same reference numerals.

FIG. 1 shows the system control process from the physical rotation acceleration process to the reading standby state in the optical disc playback device of the present invention.

In step S1, the spindle motor 2 is set not to use conventional CLV control (constant linear velocity control) but to use CAV control (constant angular velocity control). In step S2, servo adjustment is performed. In step S3, the final Import address, in step S4, carry out CLV measurement.

In step S5, the angular speed is switched to 1/2 speed of the maximum rotation speed (12 times speed if the maximum is 24 times speed).

In step S6, reading of TOC (Table of Contents), which is index information of the disc, is performed.

In step S7, the SUB-Q less than 00:02.00 is acquired (additional information for data with high function).

In step S8, the header difference is obtained from the SUB-Q in step S8, and the read-in setting is executed.

In step S9, the speed switched to 1/2 speed in step S5 is returned to the original state, and tracking is performed.

According to this configuration, since all the control is performed by CAV, the rotation waiting time is reduced and the search time is shortened.

As described above, if the optical disc reproducing device of the present invention is used to reproduce an optical disc in which information is recorded at the same density on the entire surface, CAV control is used for all processes from the start of the rotation speed-up process to the read standby state. processing, thereby having the effect of continuing the rotation at a stable rotational speed even if the focus is off, reducing the rotation waiting time, and shortening the seek time, resulting in shortening the rotation speed-up time.

Claims (2)

1. one kind at the disc reproducing apparatus to resetting with the disk-like recording medium (1) of constant linear velocity record, it is characterized in that,

Control with CAV handle the spindle drive motor (2) begin to the processing of reading till the holding state from the rotation speedup.

2. disc reproducing apparatus according to claim 1 is characterized in that, the spindle drive motor (2) in the control and treatment of disk-like recording medium (1) when the low speed rotation is controlled with CAV.

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