JP4071731B2 - Optical disc player and control method thereof - Google Patents

Description

  The present invention relates to an optical disc player that reads data stored on a disc by an optical pickup, and more particularly to a technique for preventing a situation in which reproduction performance is deteriorated or cannot be reproduced due to a change with time or an environmental change.

Conventionally, amplitude adjustment and servo gain adjustment of various signal systems obtained via an optical pickup for disk playback are all performed immediately after the disk is inserted, and playback preparation is completed at this point, which is optimal for the playback system. It is in a state. After the start of reproduction, reproduction processing is performed based on amplitude adjustment and servo gain adjustment in this preparation stage.
JP 2000-100058 A

  However, such an optimal reproduction state is not always maintained, and a change in the amplitude of each signal obtained via the pickup occurs due to a change with time or a change in environment (temperature, dust, etc.). In particular, this change is significant depending on continuous use for a long time or vibration caused by movement in a vehicle-mounted player.

  Such a change in the signal amplitude deteriorates the reading accuracy of the recording signal, and a change in the amplitude of the error signal causes a gain change in the servo system to deteriorate the reproduction performance and the defect performance. In particular, when the signal deteriorates, the minimum signal amplitude necessary for reproduction may not be obtained in the end, and the servo may come off at that time, resulting in a situation where reproduction is impossible. In such a case, in order to return the reproduction performance to the same level as when the disk reproduction was started, it was necessary to stop the reproduction of the disk and perform the adjustment again in the conventional automatic adjustment work.

  The present invention has been proposed in order to improve the above-described problems of the prior art, and an object thereof is an optical disc player for preventing a situation in which reproduction performance is deteriorated or cannot be reproduced due to a change with time or an environmental change. And providing a control method thereof.

  In order to achieve the above object, the invention of claim 1 amplifies a data signal obtained from an optical pickup and outputs an RF signal, and generates a focus error signal or a tracking error signal from the data signal. And an automatic adjustment circuit for automatically adjusting the amplitude of the RF signal, the adjustment result obtained by the automatic adjustment is stored as a register value, and the adjustment result is automatically adjusted. A register that feeds back to the circuit; an RF signal amplitude control unit that receives the register value from the register and compares this value with a preset RF signal amplitude reference value; and an error signal amplitude that adjusts the amplitude of each error signal A control unit, a change amount of the RF signal amplitude during reproduction, and a change of the error signal amplitude. A table defining a correlation with the amount, and when the RF signal amplitude control unit determines that the register value exceeds an adjustable range in the automatic adjustment circuit, the RF signal generation circuit The error signal amplitude control unit applies the conversion amount of the RF signal amplitude to the table based on the determination. The error signal amplitude control unit is configured to instruct to change the RF signal amplitude to an adjustable range in the automatic adjustment circuit. Thus, the change amount of the error signal amplitude is detected.

  The invention of claim 2 captures the invention of claim 1 from the viewpoint of a method, wherein a data signal obtained from an optical pickup is amplified by an RF signal generation circuit to output an RF signal, and from the data signal, In an optical disc player control method in which a focus error signal or a tracking error signal is generated by an error signal generation circuit, and automatic adjustment of amplitude in the RF signal is performed by an automatic adjustment circuit, an adjustment result obtained by performing the automatic adjustment by a register And the result of the adjustment is fed back to the automatic adjustment circuit, the register value is received from the register by the RF signal amplitude control unit, and this value is compared with a preset RF signal amplitude reference value. The signal amplitude control unit is a range in which the register value can be adjusted in the automatic adjustment circuit. If it is determined that the frequency exceeds the RF signal generation circuit, the RF signal generation circuit is instructed to change the RF signal amplitude to a range that can be adjusted by the automatic adjustment circuit, and the error signal amplitude control unit, based on the determination, By applying a conversion amount of the RF signal amplitude to a table that defines a correlation between the change amount of the RF signal amplitude and the change amount of the error signal amplitude during reproduction, the change amount of the error signal amplitude is detected, Further, the amplitude adjustment of each error signal is performed based on the detection.

  In the above aspect, the amplitude of the RF signal is automatically adjusted by the automatic adjustment circuit during disk reproduction, and the value obtained by the automatic adjustment is temporarily stored in the register, and this is stored in the RF signal control unit. The RF signal control unit compares the adjustment result value with the reference value of the RF signal amplitude, and determines that the result value is an amplitude signal in a range that cannot be adjusted by the automatic adjustment circuit. Change the RF signal amplitude of the circuit. Further, based on this determination, the error signal amplitude control unit determines that the error signal amplitude needs to be adjusted, and defines a focus error signal or tracking error signal amplitude change amount corresponding to the RF signal amplitude change amount. Further, the error signal amplitude is changed by applying the change amount of the RF signal amplitude.

  This makes it possible to readjust the gain of the playback system and servo system due to changes in the signal amplitude obtained from the pickup due to changes over time and environmental changes during playback, so that the disc read state is maintained without stopping playback. The same playback performance can always be recovered.

  As described above, according to the present invention, it is assumed that there is an effect on reproduction performance due to changes over time and environmental changes, and an RF signal, an error signal, generated from a signal obtained through an optical pickup during reproduction, In addition, it is possible to provide an optical disc player that adjusts the amplitude of a signal used for reproduction to prevent a change in reproduction performance or a situation where reproduction cannot be performed, and a control method therefor.

  Next, the best mode for carrying out the present invention (hereinafter referred to as the present embodiment) will be specifically described with reference to the drawings.

〔Constitution〕
In the optical disk player of the present embodiment shown in FIG. 1 (hereinafter referred to as the present apparatus), the optical pickup 1 irradiates the disk D with a light beam, so that a data signal recorded from the reflected light of the disk D is obtained. The RF signal generation circuit 2 is an optical reading means, and outputs an RF signal obtained by amplifying a data signal obtained from the optical pickup 1 as a reproduction signal.

  The RF signal amplitude automatic adjustment circuit 3 performs so-called AGC (Automatic Gain Control), receives an RF signal input from the RF signal generation circuit 2, detects the amplitude of this signal, and sets it in advance. It is automatically adjusted based on the set value, and the signal level of the RF signal is always kept constant. This set value is fed back from the amplitude adjustment result register 5 described later at a predetermined timing. The A / D converter 4 digitally converts the RF signal automatically adjusted by the adjustment circuit 3 and outputs the result to the amplitude adjustment result register 5 as an adjustment result.

  The amplitude adjustment result register 5 temporarily stores a register value as an automatic adjustment result input from the A / D converter 4 and feeds back the value of the adjustment result to the RF signal automatic adjustment circuit 3. It is configured. Further, the register 5 transmits the adjustment result to an RF signal amplitude controller 9b of the controller 9 described later.

  The error signal generation circuit 6 generates a focus error signal indicating the amount of deviation in the optical axis direction of the objective lens in the optical pickup 1 or generates a tracking error signal indicating the amount of deviation of the objective lens in the radial direction. is there. The error signal amplitude setting circuit 7 adjusts the focus error signal amplitude and the tracking error signal amplitude by an input from the control unit 9 to be described later. The A / D conversion unit 8 is connected to the setting circuit 7. The error signal amplitude detected in this way is digitally converted.

  Further, the actuator 12 includes a focus servo that moves and adjusts the optical pickup 1 in the focus direction, and a tracking servo that moves and adjusts the optical pickup 1 in the tracking direction. The driver 11 is means for driving the actuator 12 and the spindle motor 13. Further, the servo controller 10 is means for controlling the driver 11.

  Further, the present apparatus includes a control unit 9, which is configured to store a preset value of the RF signal amplitude, that is, a set value in which a range in which the amplitude can be adjusted by the RF signal amplitude automatic adjustment circuit 3 is stored. By receiving the register value as the adjustment result stored in the storage unit 9a and the amplitude adjustment result register 5, and comparing this with the set value stored in the set value storage unit 9a, the register value becomes the set value. An RF signal amplitude control unit 9b for determining whether or not the signal is within the range is provided. When the RF signal amplitude control unit 9b determines that the register value is out of the set value range, the gain setting of the RF signal generation circuit 2 is changed, and the adjustment range of the automatic adjustment circuit unit is changed. The output of the RF signal generation circuit unit is performed as an RF signal amplitude change command so as to be within.

  Further, the control unit 9 is provided with an error signal amplitude control unit 9c and an error signal amplitude table 9d. In the error signal amplitude control unit 9c, when the above-described RF signal amplitude control unit 9b determines that the register value is out of the set value range, the error signal amplitude also deviates from the optimum value. The error signal amplitude setting circuit 7 is instructed to change the amplitude. At that time, as shown in FIG. 3, the amplitude change amount of the focus error signal and the tracking error signal with respect to the change amount of the RF signal amplitude detected by the RF signal amplitude control unit 9b is set in advance. Based on the error signal amplitude table 9d, an amplitude change is instructed.

[Function and effect]
The operation of the present embodiment configured as described above will be specifically described.
First, when the disc D is inserted, the disc D is detected and the type is discriminated, and then the reproduction preparation operations such as focus search and focus servo by the optical pickup 1 are performed, and the TOC recorded on the disc D is recorded. Data can be read. Then, after the TOC data is read, the reproduction process is started. During reproduction, the amplitude of the RF signal in the RF signal generation circuit 2 and the RF signal amplitude automatic adjustment circuit 3 is always adjusted by the amplitude automatic adjustment function.

  The RF signal adjusted by the amplitude automatic adjustment function as described above is digitally converted by the A / D converter 4 and output to the amplitude adjustment result register 5 as an adjustment result register value. The amplitude adjustment result is temporarily stored as a register value in the amplitude adjustment result register 5 and fed back to the RF signal amplitude automatic adjustment circuit 3. At the same time, this register value is transmitted to the RF signal amplitude controller 9b.

  Next, the process of the control part 9 is demonstrated using the flowchart of FIG. The RF signal amplitude control unit 9b that has received the adjustment result register value first reads this data (step 201), and then stores the adjustment result register value in advance in the RF signal amplitude reference stored in the set value storage unit 9a. When the register value is within the set range, that is, within the range adjustable by the RF signal amplitude automatic adjustment circuit 3, the reproduction is continued as it is (YES in step 201).

  On the other hand, when the register value is out of the setting range, the RF signal amplitude control unit 9b determines that the RF amplitude in the RF generation circuit 2 is excessive or insufficient (NO in step 201). Based on this, it is assumed that the output of the RF generation circuit unit 2 may be outside the adjustment range of the RF signal amplitude automatic adjustment circuit, and the amplification factor setting of the RF signal generation circuit unit is changed within the adjustment range. A command is sent from the RF signal amplitude controller 9b to the RF signal generation circuit 2 (step 203).

  At the same time, based on the determination that the RF signal amplitude controller 9b needs to adjust the RF signal amplitude, it is determined that the error signal amplitude needs to be adjusted, and each of the focus error amplitude and the tracking error amplitude is determined. Is adjusted (steps 204 and 205).

  For example, as shown in FIG. 3, the error signal is adjusted by referring to an error signal amplitude table 9d calculated by examining the correlation between the RF signal and the error signal in advance, and focusing according to the amount of change in the RF signal amplitude. The required change amount of the error and tracking error signal is set, and the amplitude is changed according to the setting table. Specifically, when the deviation of the RF signal is 0.3 V, it is determined that the focus error signal and the tracking error signal are 0.2 V, and based on this, the error signal amplitude setting circuit 7 is determined. Command to change the amplitude.

  It should be noted that since this table data has a change amount of the focus error signal or the tracking error signal with respect to the change amount of the RF signal being different for each device, it is necessary to prepare appropriate data for the device.

  According to the present embodiment as described above, during reproduction, the RF signal amplitude is always adjusted in two stages of the RF signal generation circuit unit 2 and the RF signal amplitude automatic adjustment circuit 3, and the automatic adjustment result is registered in the register. The value is temporarily stored in the amplitude adjustment result register 5 as a value. Then, it is fed back to the RF signal amplitude automatic adjustment circuit 3 and simultaneously transmitted to the RF signal amplitude control unit 9b. In the RF signal amplitude control unit 9b, when the register value is not within the adjustable range of the RF signal amplitude automatic adjustment circuit 3 by comparing with the preset reference value, the RF signal generation circuit 2 is Send RF signal amplitude change command. Further, based on this determination, the error signal amplitude control unit 9c determines that the error signal amplitude needs to be adjusted, and determines the amplitude change amount of the focus error signal or the tracking error signal corresponding to the change amount of the RF signal amplitude. The error signal amplitude is changed by applying the change amount of the RF signal amplitude to the specified error signal amplitude table 9d.

  This makes it possible to readjust the gain of the playback system and servo system due to changes in the signal amplitude obtained from the pickup due to changes over time and environmental changes during playback, so that the disc read state is maintained without stopping playback. The same playback performance can always be recovered.

The system block diagram which shows the structure of embodiment of this invention. The flowchart which shows an example of the process sequence in embodiment of this invention. The figure which shows an example of the data in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical pick-up 2 ... RF signal generation circuit 3 ... RF signal amplitude automatic adjustment circuit 3 ... RF signal amplitude automatic adjustment circuit 4, 8 ... A / D conversion part 5 ... Amplitude adjustment result register 6 ... Error signal generation circuit 7 ... Error Signal amplitude setting circuit 9 ... Control unit 9a ... Set value storage unit 9b ... RF signal amplitude control unit 9c ... Error signal amplitude control unit 9d ... Error signal amplitude table 10 ... Servo controller 11 ... Driver 12 ... Actuator 13 ... Spindle motor D ... disk

Claims (2)

An RF signal generation circuit that amplifies a data signal obtained from an optical pickup and outputs an RF signal, an error signal generation circuit that generates a focus error signal or a tracking error signal from the data signal, and automatic adjustment of amplitude in the RF signal In an optical disc player equipped with an automatic adjustment circuit for performing
A register that stores the adjustment result obtained by the automatic adjustment as a register value, and a register that feeds back the adjustment result to the automatic adjustment circuit;
An RF signal amplitude controller that receives the register value from the register and compares the value with a preset RF signal amplitude reference value;
An error signal amplitude control unit for adjusting the amplitude of each error signal;
A table defining the correlation between the amount of change in the RF signal amplitude and the amount of change in the error signal amplitude during reproduction;
The RF signal amplitude control unit can adjust the RF signal amplitude with respect to the RF signal generation circuit in the automatic adjustment circuit when it is determined that the register value exceeds the range adjustable in the automatic adjustment circuit. Configured to instruct to change to the scope,
The error signal amplitude control unit is configured to detect a change amount of the error signal amplitude by applying a conversion amount of the RF signal amplitude to the table based on the determination. Player. A data signal obtained from the optical pickup is amplified by an RF signal generation circuit and an RF signal is output. A focus error signal or a tracking error signal is generated from the data signal by an error signal generation circuit, and the amplitude of the RF signal is automatically adjusted. In an optical disc player control method in which an automatic adjustment circuit performs an error signal amplitude adjustment by an error signal amplitude control unit,
The adjustment result of the automatic adjustment by a register is stored as a register value, and the adjustment result is fed back to the automatic adjustment circuit,
An RF signal amplitude control unit receives the register value from the register, compares this value with a preset RF signal amplitude reference value,
The RF signal amplitude control unit can adjust the RF signal amplitude with respect to the RF signal generation circuit in the automatic adjustment circuit when it is determined that the register value exceeds the range adjustable in the automatic adjustment circuit. Instructed to change to scope,
The error signal amplitude control unit applies the conversion amount of the RF signal amplitude based on the determination to a table that defines the correlation between the change amount of the RF signal amplitude and the change amount of the error signal amplitude during reproduction. Thus, the control method of the optical disc player, wherein the change amount of the error signal amplitude is detected and the amplitude of each error signal is adjusted based on the detection.

Images