JP2005293711A - Optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk device which reduces power consumption while keeping the high following performance of a pickup. <P>SOLUTION: The optical disk device rotates and controls an optical disk at a rotational speed in a prescribed range so that a track immediately adjacent to an optical pickup may move at a constant speed and performs focus control and tracking control for the optical disk by means of sampled data control. The optical disk device is provided with; identification means (S4 and S6) which identify the rotational speed of the optical disk in multiple ranges; and switching means (S8, S14 and S18) which switch the sampling frequency of the sampled data control according to the range identified by the identification means (S4 and S6). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical disc apparatus that controls rotation of an optical disc at a rotational speed within a predetermined range so that a track closest to the optical pickup moves at a constant speed, and executes focus control and tracking control of the optical disc by sample value control. It is about.

  For example, as shown in the explanatory diagram of FIG. 3, the CD (Compact Disc) starts from 500 rpm at the innermost rotation so that the track closest to the optical pickup moves at a constant speed (CLV; Constant Linear Velocity). When the outermost periphery rotates, the rotation of the optical disk is controlled up to 200 rpm. Since an error due to vibration or the like is likely to occur during high-speed rotation, a high follow-up performance of the pickup is required. However, during low-speed rotation, the rotation of the optical disk is relatively stable, and thus high follow-up performance is not necessary.

Further, in recent digital control theory considering the response between sample points as described in Non-Patent Document 1, in order to design a control device taking into account the digital operation (especially phase delay) of the actuator. Thus, it is possible to obtain good performance without being greatly influenced by the sampling frequency.
Japanese Patent No. 3341830 System Control Information Society Mitsuhiko Araki “Introduction to Digital Control Theory” Asakura Shoten 10th October, 2002 10th edition

  Optical disc apparatuses are required to save power as well as high tracking performance against disturbances such as vibrations. In particular, in a portable optical disc device, since there are many disturbances due to carrying around and there is a limit to battery capacity, both tracking performance and power saving are important factors. Conventionally, the sampling frequency of the error signal is constant at 44.1 kHz, but there is a problem that the power consumption increases when the sampling frequency is increased in order to improve the follow-up performance.

Patent Document 1 discloses an optical disc apparatus in which, when processing a signal of a plurality of channels, a sampling frequency is set for each channel to improve performance while aiming at low power consumption.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an optical disc apparatus capable of reducing power consumption while maintaining high tracking performance of a pickup.

  The optical disk apparatus according to the first aspect of the invention controls the rotation of the optical disk at a rotation speed within a predetermined range so that the track closest to the optical pickup moves at a constant speed, and performs sample value control for focus control and tracking control of the optical disk. In the optical disk device executed by the above, an identification means for identifying the rotation speed of the optical disk in a plurality of ranges, and a switching means for switching the sampling frequency of the sample value control according to the range identified by the identification means. And

In this optical disc apparatus, the optical disc is controlled to rotate at a rotation speed within a predetermined range so that the track closest to the optical pickup moves at a constant speed, and focus control and tracking control of the optical disc are executed by sample value control. The discriminating unit discriminates the rotational speed of the optical disc into a plurality of ranges, and the switching unit switches the sampling frequency of the sample value control according to the range identified by the discriminating unit.
In addition, since a control device that performs focus control and tracking control by sample value control is designed based on the recent digital control theory described in Non-Patent Document 1, the sampling frequency that the switching means switches is It is possible to switch to a frequency lower than the maximum frequency while maintaining the following force.

  In the optical disk device according to the second aspect of the invention, the identifying means identifies the range of the predetermined range on the high speed side 1/4, the range of the intermediate speed 1/2, and the range of the low speed 1/4. The switching means is configured to switch to the highest frequency of the sampling frequency, 1/2 of the highest frequency, and 1/4 of the highest frequency, respectively.

In this optical disc apparatus, the identification means identifies the range of 1/4 of the predetermined range on the high speed side, the range of 1/2 of the intermediate speed, and the range of 1/4 on the low speed side, and the switching means , Switching to the highest frequency of the sampling frequency, 1/2 of the highest frequency, and 1/4 of the highest frequency.
In addition, since the control device that executes the focus control and the tracking control by the sample value control is designed based on the recent digital control theory described in Non-Patent Document 1, the sampling frequency to be switched by the switching means is It is possible to switch to 1/2 and 1/4 of the maximum frequency while maintaining the following force.

  According to the optical disc apparatus according to the first and second inventions, it is possible to realize an optical disc apparatus capable of reducing power consumption while maintaining high follow-up performance of the pickup.

Hereinafter, the present invention will be described with reference to the drawings showing embodiments thereof.
FIG. 1 is a block diagram showing a configuration of an embodiment of an optical disc apparatus according to the present invention. This optical disc device is a recordable / reproducible mini disc device. In a state where a rectangular flat cartridge 12 containing the mini disc 11 is loaded in the mini disc device, the shutters on both sides of the cartridge 12 are opened and the mini disc is opened. 11, when the optical pickup 15 reads and records from one surface through the objective lens 14, a magnetic field by the magnetic head 19 is applied to the other surface of the mini disk 11.

  The mini disk 11 is rotationally driven by a spindle motor 13 so as to have a predetermined constant linear velocity, and the optical pickup 15 is driven by a feed motor 16 and moves in the radial direction of the mini disk 11. The magnetic head 19 is driven by the head drive unit 20 during recording and moves in the radial direction of the mini-disc 11, and the position of the magnetic head 19 is controlled so as to sandwich the same track with the optical pickup 15 from both sides.

The spindle motor 13, the optical pickup 15 and the feed motor 16 are driven and controlled by a servo control unit 17.
The servo control unit 17 includes a tracking control unit 32 and a focus control unit 33 designed based on the recent digital control theory described in Non-Patent Document 1. The tracking control unit 32 and the focus control unit 33 perform sample value control (digital control) for each actuator built in the optical pickup 15 at a sampling frequency switched to any of 44.1 kHz, 22.0 kHz, or 11.0 kHz. To do.

The signal detected by the optical pickup 15 is sent to an RF (Radio Frequency) amplifier 22 and amplified. Of the signals amplified by the RF amplifier 22, the focus error signal and the tracking error signal are sent to the servo control unit 17 and given to the focus control unit 33 and the tracking control unit 32.
The focus control unit 33 receives a surface blur component signal of the optical disk as a tracking target value from the system controller 18 described later, and executes the above-described sample value control based on the focus error signal supplied from the RF amplifier 22.
The tracking control unit 32 receives the eccentric component signal that is the tracking target value from the system controller 18, and executes the above-described sample value control based on the tracking error signal provided from the RF amplifier 22.

Of the signals amplified by the RF amplifier 22, the address signal is sent to the address decoder 21, decoded, and given to the encoder / decoder 23.
The address signal sent to the encoder / decoder 23 and decoded is used for the position control of the magnetic head 19 by the head drive unit 20 and also sent to the system controller 18 for spindle motor 13 and optical pickup 15 by the servo control unit 17. And used for drive control of the feed motor 16 and the like.

  The data signal among the signals amplified by the RF amplifier 22 is sent to the encoder / decoder 23, decoded, and sent to the DRAM 25 (Dynamic Random Access Memory) through the anti-vibration memory controller 24. The data sent to the DRAM 25 is temporarily stored, then sent to the voice compression encoder / decoder 26 through the anti-vibration memory controller 24, decoded into voice data before voice compression, and outputted through the D / A converter 28. The

  The voice data input through the A / D converter 27 is voice-compressed and coded by the voice compression encoder / decoder 26 and sent to the DRAM 25 through the anti-vibration memory controller 24. The data sent to the DRAM 25 is temporarily stored, then sent to the encoder / decoder 23 through the vibration proof memory controller 24, coded, and recorded on the mini disk 11 by the magnetic head 19 and the optical pickup 15.

The vibration-proof memory controller 24 and the DRAM 25 prevent sound skipping due to vibration or the like by using the difference between the time required for storage in the DRAM 25 and the time required for reading from the DRAM 25.
The system controller 18 is connected to the display unit 29, the clock circuit 30, and the operation unit 31, and controls the operation of the servo control unit 17, the encoder / decoder 23, and the anti-vibration memory controller 24. The designated information is displayed on the display unit 29.

Hereinafter, the operation of the servo control 17 of such an optical disk apparatus will be described with reference to the flowchart of FIG.
The servo controller 17 reads the rotational speed of the mini disk 11 from the system controller 18 (S2), and determines whether or not the read rotational speed is 425 rpm or more (S4). If it is 425 rpm or more, the clock frequency is set to 44.1 kHz (S14), the tracking error signal is sampled at 44.1 kHz (S16), provided to the tracking control unit 32 (S12), the sample value control is executed, and the process returns. .

  If the read rotation speed is not 425 rpm or more (S4), the servo control unit 17 determines whether the read rotation speed is 275 rpm or more (S6). If it is 275 rpm or more, the clock frequency is set to 22 kHz (S18), the tracking error signal is sampled at 22 kHz (S20), given to the tracking controller 32 (S12), sample value control is executed, and the process returns.

  If the read rotational speed is not 275 rpm or more (S6), the servo control unit 17 sets the clock frequency to 11 kHz (S8), samples the tracking error signal at 11 kHz (S10), and gives it to the tracking control unit 32 ( S12) Execute sample value control and return. The operation described above relates to tracking control, but the operation related to focus control is the same.

1 is a block diagram showing a configuration of an embodiment of an optical disc device according to the present invention. 4 is a flowchart showing an operation of servo control of the optical disc apparatus according to the present invention. It is explanatory drawing for demonstrating the optical disk apparatus of a CLV system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Mini disk 13 Spindle motor 14 Objective lens 15 Optical pick-up 16 Feed motor 17 Servo control part (identification means, switching means)
18 System Controller 19 Magnetic Head 32 Tracking Controller 33 Focus Controller

Claims (2)

In an optical disc apparatus that controls rotation of an optical disc at a rotation speed within a predetermined range so that a track closest to the optical pickup moves at a constant speed, and performs focus control and tracking control of the optical disc by sample value control.
An optical disc apparatus comprising: identification means for identifying the rotation speed of the optical disc in a plurality of ranges; and switching means for switching the sampling frequency of the sample value control according to the range identified by the discrimination means.   The discriminating means discriminates into a range of 1/4 of the predetermined range on the high speed side, a range of 1/2 of the intermediate speed, and a range of 1/4 on the low speed side. 2. The optical disk apparatus according to claim 1, wherein the optical disk apparatus is switched to a maximum frequency, 1/2 of the maximum frequency, and 1/4 of the maximum frequency.

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