JP2793152B2 - Playback device for optical disk record carrier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk having a function of reproducing information recorded on an optical disk recording carrier such as a compact disk (hereinafter abbreviated as "CD") as data, and having an automatic adjustment function of an optical servo system. The present invention relates to an apparatus for reproducing a record carrier.

[0002]

2. Description of the Related Art In an information reproducing apparatus using laser light, such as a CD, a video disk (abbreviation "VD"), a mini disk (abbreviation "MD") or a magneto-optical disk, a large amount of information recorded at a high density is used. In order to reliably read the information, servo control is used particularly in the optical system.
Further, many in-vehicle CD reproducing devices and the like have an automatic adjustment function because of a large change in operating environment and large vibrations. For example, a focus servo and a tracking servo are used for an optical head that reads data from the surface of a CD. Servo control is also performed on a disk motor that rotationally drives a CD.

As automatic adjustment of servo control, adjustment of a gain and a control range of a servo system is performed. In the conventional CD reproducing apparatus, automatic adjustment is performed only when (a) a CD is mounted on the reproducing apparatus, or (b) when a control microcomputer or the like returns from a reset state. When a CD is newly inserted, it is necessary to read so-called TOC information of the CD first, and automatic adjustment is performed as a series of sequences in accordance with the TOC information. When the control microcomputer or the like returns from the reset state, automatic adjustment is performed according to the initial settings in a preset program.

[0004]

After a CD or the like is once mounted on a reproducing apparatus, the same portion may be repeatedly reproduced many times, or a large amount of information may be reproduced over a long period of time. In such a case, since the automatic adjustment is not performed, the optical servo system or the like may deviate from the optimum adjustment position during the reproduction, and the reproduction capability may be reduced. When the reproduction capability is reduced and a data error or the like occurs, the reproduction of the CD is stopped. Once playback is stopped, automatic adjustment is not performed and the playback capability cannot be restored unless the CD is ejected and inserted again or the microcomputer is reset. simply,
Even if an attempt is made to perform the reproduction operation again with the CD mounted, automatic adjustment for error recovery is not performed.

An object of the present invention is to provide a reproducing apparatus for an optical disk record carrier in which, when an error occurs and the reproduction is stopped, an automatic adjustment is performed simply by giving an instruction to start the reproduction.

[0006]

SUMMARY OF THE INVENTION The present invention provides a method for reading information recorded on an optical disk record carrier as data.
In an optical disc recording carrier reproducing apparatus having an automatic adjustment function of an optical servo system, an error detecting means for detecting presence or absence of an error from information to be read and stopping reading when an error occurs, and an optical disc recording carrier by the error detecting means. And control means for re-adjusting the optical servo system using an automatic adjustment function when reproduction is instructed after reading from the optical disk is stopped. According to the present invention, when information read from the optical disk record carrier has a data error, the reading is stopped by the error detecting means. When the reading from the optical disc recording carrier is instructed and the reading is stopped by the error detecting means, the control means re-adjusts the optical servo system by using the automatic adjusting function, so that the stable reproducing ability is restored. Can be done.

The error detecting means of the present invention is characterized in that a data reading defect is detected as an error. According to the present invention, a read failure of data read from the optical disk record carrier is detected as an error, so that a state in which the reproduction capability is reduced due to a deviation of the optical servo system caused by various causes is recovered by readjustment. be able to.

Further, the error detecting means of the present invention is characterized in that a servo deviation of the optical system is detected as an error.
According to the present invention, since the servo deviating of the optical system is detected as an error, the focus servo and the tracking servo can be readjusted by using the automatic adjustment function to recover the reproduction ability.

Further, the error detecting means of the present invention is characterized in that a synchronization detection failure is detected as an error. According to the present invention, since the error detecting means detects a synchronization detection failure as an error, it is possible to use the automatic adjustment function to readjust the deterioration of the reproduction capability due to the loss of synchronization, and recover it.

The present invention further comprises a temperature detecting means for detecting an ambient temperature, wherein the error detecting means responds to an output from the temperature detecting means and detects a state where the ambient temperature is out of a predetermined range as an error. It is characterized by the following. According to the present invention, a state in which the ambient temperature detected by the temperature detecting means is out of a predetermined range is detected as an error by the error detecting means. You can restore the ability to play.

[0011]

FIG. 1 shows an electrical configuration for controlling a CD deck according to an embodiment of the present invention. The CD deck controller 1 controls an optical pickup drive unit 2, a light emitting diode (hereinafter abbreviated as "LED") substrate 3, an insertion / ejection mechanism 4, and the like to reproduce a CD as an optical disk recording carrier. In the CD deck controller 1, a control microcomputer 5, a servo and signal processing circuit 6, a driver 7, a CD discrimination sensor 8, a discharge completion sensor 9, a clamp completion switch 10, an RF preamplifier 11, a driver 12, and an output circuit 13 and the like are mounted. The control microcomputer 5 performs various controls according to a preset program. It also performs data communication with other microcomputers, such as for control panel control, and receives commands such as playback and ejection. The servo and signal processing circuit 6 includes the optical pickup drive unit 2
A / D conversion, signal processing based on data read from
It has a function of performing signal processing including digital filter and D / A conversion, performing servo control of each actuator, and detecting an error to stop reproduction.
In particular, the servo control system has a self-adjustment function. A signal line for transmitting a control signal, a data signal, and the like is provided between the servo and signal processing circuit 6 and the control microcomputer 5.

The control microcomputer 5 drives the insertion / ejection mechanism 4 via a driver 7. Also, a CD discrimination sensor 8, a discharge completion sensor 9, and a clamp completion switch 1
An input signal from 0 is received. The CD discrimination sensor 8 determines whether the CD is an 8 cm type depending on the photo sensor
It is determined whether the type is the m type. The ejection completion sensor 9 detects whether or not the ejection of the CD has been completed by the photo sensor. The clamp completion switch 10 detects whether the CD is rotatable. An analog signal from the RF preamplifier 11 is input to the servo and signal processing circuit 6 and A / D converted. Data read from the optical pickup drive unit 2 is input to the RF preamplifier 11. The servo output output from the servo and signal processing circuit 6 is D / A converted and output to the optical pickup drive unit 2 via the driver 12. An analog signal output from the servo and signal processing circuit 6 is derived via the output circuit 13 as an analog audio output. The digital audio output output from the servo and signal processing circuit 6 is directly derived. Further, a signal from the temperature detection circuit 15 for detecting the ambient temperature is also input to the control microcomputer 5.

The optical pickup drive unit 2 includes:
An optical pickup 20, a feed motor 21, a disk motor 22, an origin switch 23 and the like are included. The optical pickup 20 includes a laser diode for generating laser light,
It includes a lens for receiving light, an actuator for adjusting the focus of the lens, and the like. The actuator is driven by an output from the driver 12. The feed motor 21 is provided for performing tracking movement of the optical pickup 20,
Driven by the driver 12. Disk motor 22
Is driven by the driver 12 to rotate the CD. The origin switch 23 detects whether or not the optical pickup 20 is at the origin position, and inputs the detection result to the control microcomputer 5.

The LED board 3 includes an insertion switch 24 for detecting that a CD is inserted, and its output is input to the control microcomputer 5. When it is detected that a CD is inserted, an LED for a deck sensor
25 is controlled to light up. The insertion / ejection mechanism 4 has C
A loading motor 26 for transporting D is included. When the insertion switch 24 detects that a CD has been inserted, the control microcomputer 5 drives the loading motor 26 via the driver 7 to convey the CD to the rotation axis of the disk motor 22. When the completion of the clamp is detected by the clamp completion switch 10 when the CD is conveyed to the rotating shaft of the disk motor 22,
D can be reproduced.

The servo and signal processing circuit 6 has a self-adjustment function for the servo systems of various actuators in the optical pickup drive unit 2. Normally,
The self-adjustment function is used based on a command from the control microcomputer 5. FIG. 2 shows an operation when the control microcomputer 5 of FIG. 1 performs self-adjustment. The operation starts from step a1, and in step a2, it is determined whether or not a CD is loaded. If not, wait for it to be attached. Next, automatic adjustment is performed in step a3. In step a4, it is determined whether or not a reset has been instructed. When reset is instructed, the process returns to step a2. Next, in step a5, it is determined whether or not the CD has been ejected. When it is determined that the sheet has been discharged, the process returns to step a2. When it is determined that the sheet is not ejected, the normal reproduction operation following the search in step a6 and the reproduction in step a7 is performed.

During the reproduction operation, it is always determined whether or not a stop which is a reproduction stop occurs. If it is not a stop, the process returns to step a4. If the stop has occurred, it is determined in step a11 whether or not an error stop has occurred. When it is judged that it is not an error stop,
This is due to the stop instruction or the end of the reproduction. In step a12, the control waits for a play instruction given from the outside. If it is determined in step a11 that an error stop has occurred, the process proceeds to step a13, and after waiting for a play instruction, automatic adjustment in step a14 is performed. Step a
After the play instruction in step 12 or the automatic adjustment in step a14, the process returns to step a6. That is, when the reproduction stop state occurs, if the error is stopped, the automatic adjustment is performed after the play instruction, and if not, the reproduction is continued after the play instruction. After the reset or the ejection of the CD, the automatic adjustment is performed as in the related art.

FIG. 3 shows a schematic internal configuration of the servo and signal processing circuit 6 shown in FIG. In the focus error detection circuit 30, amplifiers 31 and 32 for amplifying the output from the four-divided sensor for focus error adjustment are provided. Outputs from the amplifiers 31 and 32 are amplified by voltage-controlled amplifiers (VCBA) 33 and 34, respectively, are derived as high-frequency output (RFOUT) from an amplifier 35, and are provided with a low-pass filter (hereinafter abbreviated as “LPF”) 36. From the amplifier 37 as a focus error output (FEOUT). Voltage control amplifier 3
Focus balance input (FBAL) signals are input to the amplifiers 3 and 34 via the amplifier 38, and the gain is adjusted.

The tracking error detection circuit 40 is provided with filters 41 and 42 on the input side, and outputs thereof are amplified by voltage control amplifiers 43 and 44, respectively. A tracking balance input (TBAL) signal is input to the voltage control amplifiers 43 and 44 via the amplifier 45. Outputs of the voltage control amplifiers 43 and 44 are subtracted by a current value by a subtracter 46 and are derived as a tracking error output (TEOUT) via an amplifier 47. The tracking error output is also derived as a cross output (CROSS) via the amplifier 48.

A high-frequency signal is input to the data error detection circuit 50 via an EQ circuit 51 for adjusting the frequency characteristic of the output from the amplifier 35 of the focus error detection circuit 30, and the level is adjusted by an AGC circuit 52. R
The high frequency signal is detected by the F detection circuit 53. EN
The amplitude modulation component is detected by the V detection circuit 54, and the BD
The dropout is detected by the O detection circuit 55.

In the tracking offset adjustment circuit 60, if the tracking offset becomes too large,
Since the dynamic range is impaired, the offset amount is 20
Adjustment is performed so as to be within 0 to 300 mV. Since the laser diode of the optical pickup 20 is not in a sufficient extinction state at the offset capture timing even when the power is turned off, it is inevitable that the tracking offset becomes higher than the true value.

In the focus offset adjustment, the DC component of the focus error signal FE when the focus actuator of the optical pickup 20 is moved away from the CD to the lowest point is taken in as the focus offset. After this adjustment, processing is performed by subtracting the offset from the A / D converted value. The focus coarse gain adjustment uses a focus search sequence, moves the focus actuator from the highest point closest to the CD to the lowest point, and uses the maximum / minimum value of each focus error signal to adjust the disturbance input amplitude during focus gain adjustment. To determine. At this time, the focus gain itself does not change.

In the tracking coarse gain adjustment, the track is intentionally crossed by stopping the traverse, and the tracking error output (TEOUU) at this time is adjusted.
A disturbance input amplitude at the time of tracking gain adjustment is determined based on the maximum / minimum value of T). At this time, the tracking gain itself does not change. In the tracking balance adjustment, the traverse is stopped, the track is intentionally crossed, and the tracking error signal (TE) at this time is sampled. At this time, a sample in which the frequency of the track cross is a specific value is extracted, and the tracking balance input (TB) of the head amplifier is set so that the average becomes zero.
AL) is adjusted by using pulse width modulation (PWM).

As the focus fine gain adjustment, a disturbance of the amplitude determined at the time of the coarse focus gain adjustment is injected into the focus servo loop, and the gain intersection at this time is about 75 points.
The gains of the voltage control amplifiers 33 and 34, which are focus variable gain amplifiers, are adjusted to be 0 Hz. The starting point at this time is set from the value of the system setting or the value of the past adjustment result, and has a maximum adjustment range of ± 9 dB. As the tracking fine gain adjustment, the disturbance of the amplitude determined at the time of the tracking coarse gain adjustment is injected into the tracking servo loop, and the voltage control amplifiers 43 and 44 which are tracking variable gain amplifiers so that the gain intersection at this time becomes about 1 kHz. Adjust the gain of. The starting point at this time is set from the value of the system setting or the value of the past adjustment result,
It has an adjustment range of up to ± 9 dB.

FIG. 4 shows a format of information recorded on a CD. FIG. 4A shows a frame format,
FIG. 4B shows the sub-coding frame format. In the frame format shown in FIG. 4A, a 24-bit periodic pattern is first provided as the frame synchronization signal 70, a 1-symbol = 14-bit sub-coding 71 follows, 12-symbol data 72, and 4-symbol parity 73 , 12 symbols of data 74 and 4 symbols of parity 75. Each symbol has 14 bits, and 3-bit data is interposed between the symbols for combining. In the sub-coding frame format of FIG.
6, subcoding 77 and data and parity 78
Consists of Information indicating the position of the head of the music recorded on the CD is recorded in the subcoding 77 portion. Parity and the like are added to the information recorded on the CD, and the servo and signal processing circuit 6 can detect whether an error has occurred in the read data.

FIG. 5 shows an example of the temperature detection circuit 15. In the optical pickup 20, the laser diode generates a considerable amount of heat, and if the ambient temperature is high, the junction temperature becomes high. Therefore, it is necessary to add thermal protection. In the temperature detection circuit 15 shown in FIG. 5, when the thermistor 71 changes the resistance value according to the temperature, the signal voltage output to the control microcomputer 5 via the transistors 72 and 73 changes. The data is converted into digital data by an A / D conversion circuit in the control microcomputer 5, and the temperature is converted into a digital value to determine whether or not the temperature is within an allowable range. Even if the temperature does not rise until the laser diode is turned off to protect the laser diode of the optical pickup 20, the optical servo system may deviate from the optimum balance point due to the temperature change. In this embodiment, when such a temperature change occurs, the reproduction is stopped, and automatic adjustment is performed when the temperature is restarted, so that the reproduction capability can be restored.

In the above embodiment, the case where a CD is used as a record carrier has been described. However, an automatic adjustment of the optical servo system is similarly performed for other optical disc record carriers such as MD and VD, so that an error can be generated. The reproduction ability at the time can be recovered.

[0027]

As described above, according to the present invention, when the optical servo system reproduces the optical disk record carrier from the optimum state of adjustment due to some influence and stops due to an error during reproduction, the optical disk record carrier is removed. The automatic adjustment can be performed simply by instructing the reproduction again without once discharging or resetting the microcomputer or the like, and the stable reproduction ability can be restored.

Further, according to the present invention, even if the reproduction is stopped due to a data reading defect, the automatic adjustment is performed by instructing the reproduction, so that it is possible to recover from the data reading defect by readjustment.

Further, according to the present invention, it is possible to detect the servo deviation of the optical system as an error, and when the reproduction is next instructed, readjust by using the automatic adjustment function to recover the servo deviation.

According to the present invention, when reproduction is instructed after the reproduction is stopped after the synchronization detection failure is detected as an error, readjustment is performed using the automatic adjustment function, so that the synchronization detection failure is recovered. be able to.

Further, according to the present invention, after the reproduction is stopped in a state where the ambient temperature is out of the predetermined range, when the reproduction is instructed, the automatic adjustment is performed, and the reproducing function can be restored in a state where the ambient temperature is adjusted. it can.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic electrical configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the control microcomputer of FIG. 1;

FIG. 3 is a block diagram showing an internal configuration of a servo and signal processing circuit of FIG. 1;

FIG. 4 is a diagram showing a data structure recorded on a CD.

FIG. 5 is an electric circuit diagram showing an internal configuration of the temperature detection circuit of FIG.

[Explanation of symbols]

 Reference Signs List 1 CD deck control device 2 Optical pickup drive unit 4 Insertion / ejection mechanism 5 Control microcomputer 6 Servo and signal processing circuit 15 Temperature detection circuit 20 Optical pickup 21 Feed motor 22 Disk motor 30 Focus error detection circuit 40 Tracking error detection circuit 50 Data error Detection circuit 60 Tracking offset adjustment circuit

Continuation of front page (56) References JP-A-6-302104 (JP, A) JP-A-62-239387 (JP, A) JP-A-6-318326 (JP, A) JP-A-4-268267 (JP) JP-A 1-312745 (JP, A) JP-A 4-248133 (JP, A) JP-A 7-73574 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB G11B 7/09-7/095 G11B 19/02 501 G11B 19/04 501

Claims (5)

(57) [Claims] 1. An optical disk recording carrier reproducing apparatus having an automatic adjustment function of an optical servo system for reading information recorded on an optical disk recording carrier as data, detecting whether or not an error has occurred from the read information. An error detecting means for stopping reading when an error occurs, and a control for re-adjusting the optical servo system by using an automatic adjustment function when reproduction is instructed after reading from the optical disk record carrier is stopped by the error detecting means. Means for reproducing an optical disk record carrier. 2. An apparatus according to claim 1, wherein said error detecting means detects a data reading defect as an error. 3. An apparatus according to claim 1, wherein the error detecting means detects a servo deviation of the optical system as an error. 4. The apparatus according to claim 1, wherein the error detecting means detects a synchronization detection failure as an error. 5. An apparatus according to claim 1, further comprising a temperature detecting means for detecting an ambient temperature, wherein the error detecting means responds to an output from the temperature detecting means,
2. The apparatus according to claim 1, wherein a state in which the ambient temperature is out of a predetermined range is detected as an error.