JP2506659B2 - Information recording / reproducing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording / reproducing apparatus for recording or reproducing information by a signal converting means on a record carrier having information recorded tracks or tracks for recording information. It is about.

2. Description of the Related Art As a conventional optical information recording / reproducing apparatus, as shown in, for example, Japanese Patent Application Laid-Open No. 57-69111, a record carrier is produced by modulating a light beam generated from a light source such as a semiconductor laser strongly. There is a device for recording a signal on it and reproducing a signal recorded on a record carrier by making a light beam generated from a light source constant. The configuration of this device will be briefly described below.

The disk-shaped record carrier used in the apparatus is attached to a rotating means, for example, a rotating shaft of a motor, and is rotated at a predetermined rotation speed. The record carrier is composed of a base material, a layer having concentric concavo-convex grooves (hereinafter referred to as tracks), a recording material layer and a protective layer, and each track is sequentially provided with an address signal from the outer circumference to the inner circumference. There is. The conversion means is composed of an optical system for converging the light beam generated by the light source on the recording material layer of the record carrier and a photodetector for detecting the reflected light from the record carrier. A part of the optical system is attached to the first moving means, and is configured so that the light beam irradiated on the record carrier by the first moving means moves in a narrow range in a direction substantially perpendicular to the track direction. ing. First
The moving means and the entire signal converting means are attached to the transfer table, and are configured to be movable in the radial direction of the record carrier integrally with the transfer table by the second moving means, for example, a linear motor. When the tracking control is operating, the second moving means is controlled so that the first moving means moves around a natural state (this control is hereinafter referred to as transfer control).

When the record carrier is rotated by the rotating means, the tracks on the record carrier are eccentric. The loop gain of the tracking control system must be made extremely large in order to track the track on which the light beam is located without displacement when the tracking control is operated. Needless to say, in order to increase the loop gain of the tracking control system, the S / N ratio (signal to noise ratio) of the tracking control signal and the characteristics of the first moving element are improved, but the reflectivity of the record carrier is increased. It is necessary to consider the margin for the gain change of the tracking control system such as change, decrease in light amount due to dust, change in light beam light amount generated from the light source, etc., so that the loop gain of the tracking control system becomes a predetermined value or more in the worst condition. Is extremely difficult to achieve. Therefore, in the conventional device, the tracking control is operated, the track deviation signal is converted into a digital signal by the A / D conversion means,
This digital signal is synchronized with the rotation means and stored in the storage means during one rotation of the record carrier, and then the signal stored in the storage means is read in synchronization with the rotation means, and the read signal is analogized by the D / A conversion means. By converting the signal into a signal and adding the analog signal to the track deviation signal, the track deviation is corrected without increasing the loop gain of the tracking control system.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-mentioned configuration, the track deviation signal is converted into a digital signal by the A / D conversion means, and the digital signal is synchronized with the rotation means and stored while the record carrier makes one rotation. When the data is stored in the recording medium, scratches, dirt on the record carrier, or vibration of the device may disturb the tracking control, and the light beam may jump over a predetermined track of the record carrier. Therefore, the disturbed signal of the tracking control means is stored in the storage means. After that, the storage signal of the storage means is read in synchronization with the rotation means, the read signal is converted into an analog signal by the D / A conversion means, and this analog signal is added to the track deviation signal of the tracking control means. . For this reason, the stable tracking control is disturbed, the track shift is increased, the track is jumped, and the moving means of the tracking control means is destroyed.

In view of such a point, the present invention, when storing in the storage means,
It is an object of the present invention to provide an information recording / reproducing apparatus that causes the signal of the tracking control means to be stored in the storage means again when the light beam is largely deviated from a predetermined track of the record carrier, so that stable tracking control is always performed.

The present invention relates to a rotating means for rotating a disk-shaped record carrier having a track, a signal converting means for reproducing or recording a track on the record carrier, and a signal converting means for the signal converting means. The tracking control means for controlling the scanning position to be located on the track on the record carrier, the storage means for storing the signal of the tracking control means, and the scanning position for the signal converting means are deviated from the track on the record carrier. When this is detected, the information recording / reproducing apparatus is configured to store the signal of the tracking control means again in the storage means.

Action The present invention has the above-described configuration, and when the data is stored in the storage means, the tracking control is disturbed due to scratches, dirt on the record carrier, vibration of the device, and the like, and the light beam largely deviates from the track on the record carrier. When detected by the detection means, the signal of the tracking control means is stored again in the storage means, and when the track deviation detection means detects a large deviation from the track, the operation of the apparatus is stopped.

Practical Example FIG. 1 is a block diagram of an information recording / reproducing apparatus in an example of the present invention. In FIG. 1, reference numeral 1 denotes a recording material layer on a UV layer (ultra violet layer) having a spiral concave-convex groove provided on a base material such as acrylic, and a protective layer provided on the recording material layer. In the configured recording disk, track address signals are sequentially recorded in advance from the outer circumference toward the inner circumference in the groove.

Reference numeral 2 is a motor for rotating the recording disk 1 at a predetermined rotation speed.

3 is a semiconductor laser, 4 is a light beam, 5 is a coupling lens, 6 is a beam splitter, 7 is a reflecting mirror, 8 is a converging lens, and 9 is a photodetector having a two-divided structure. Reference numeral 10 is a differential amplifier circuit for amplifying the difference between the output signals of the photodetectors 9, and 11 is a switch for turning on / off the output signal of the differential amplifier circuit 10. The output of the switch 11 is the synthesis circuit 12
And is input to the low-pass filter 13. The signal of the low-pass filter 13 is input to the A / D conversion circuit (analog-digital conversion circuit) 14, and the A / D conversion circuit 14 converts the input analog signal into a digital signal and RAM (random access memory). Remember in 15. The digital signal stored in RAM15 is the D / A conversion circuit (digital-
Analog conversion circuit) 16 to convert to an analog signal,
It is input to the combining circuit 12 via the switch 17. Synthesis circuit
Reference numeral 12 synthesizes the signal of the differential amplifier circuit 10 input via the switch 11 and the signal of the D / A conversion circuit 16 input via the switch 17 and inputs them to the phase compensation circuits 18 and 19, respectively.
The phase compensating circuit 18 is a circuit for compensating the phase of the system and is composed of a filter or the like. The signal of the phase compensation circuit 18 is input to the drive circuit 20, and the drive circuit 20 drives the tracking element 21.

The phase compensating circuit 19 is a circuit for compensating the phase of the system and is configured by a filter or the like, and the signal of the phase compensating circuit 19 is input to the drive control circuit 22.

The speed detector 24 is for detecting the moving speed of the transfer table 25 and is composed of a movable portion 24A and a fixed portion 24B, and the output of the fixed portion 24B is input to the drive control circuit 22. The drive control circuit 22 includes a phase compensation circuit 19 and a speed detector 24.
Is a circuit for controlling the linear motor 23 based on the output signal of the.

The semiconductor laser 3, the coupling lens 5, the beam splitter 6, the reflecting mirror 7, the speed collecting lens 8, the photodetector 9, the tracking element 21, and the movable portion 24A of the speed detector are the transfer table 25.
Is attached to the recording disk 1 so that it can move in the radial direction of the recording disk 1 as a unit.

Reference numeral 26 is a one-rotation detector that outputs a one-pulse signal when the motor 2 makes one rotation. The one-rotation detector is composed of a rotating portion and a fixed portion, and the rotating portion is configured to rotate together with the rotating shaft of the motor 2.
The signal of the one-rotation detector 26 is input to the waveform shaping circuit 27, is shaped into the waveform, and then is input to the binarization circuit 28. Binarization circuit 28
Compares the input signal with a predetermined level and
It is a circuit for converting into a GH "digital signal. The signal of the binarization circuit 28 is a pulse generation circuit 29 and an address counter.
Entered in 30. The pulse generation circuit 29 is an information processing control circuit
While the motor 2 makes one rotation by the command of 32 (line MST), that is, the section in which the signal of the binarization circuit 28 receives 2 pulses,
Input the memory command signal (line WE) to RAM (random access memory) 15. The address counter 30 uses the signal input from the binarization circuit 28 as a reset signal (line R) and the signal generated by the reference frequency generation circuit 31 as a clock signal (line CK), and inputs the reset signal (line R). And the internal counters are all cleared, the clock signal (line CK) input after clearing is counted by the counter, and the output of this counter is input to the RAM 15 and the information processing control circuit 38 as an address signal (line ADR). .

The frequency generator 33 generates a signal having a frequency according to the rotation speed of the motor 2, and is divided into a rotating portion and a fixed portion, and the rotating portion is configured to rotate with the rotation shaft of the motor 2. There is. The signal of the frequency generator 33 is input to the waveform shaping circuit 34, and the signal waveform-shaped by the waveform shaping circuit 34 is input to the F / V conversion circuit (frequency-voltage conversion circuit) 35 and the phase comparison circuit 36. The F / V conversion circuit 35 inputs the signal converted by the conversion circuit that generates a voltage according to the frequency of the input signal to the synthesis circuit 37. Phase comparison circuit
The signal generated by the reference frequency generation circuit 31 and the signal of the waveform shaping circuit 34 are input to the 36, and the phase comparison circuit 36 generates a signal corresponding to the phase difference between these two signals and inputs it to the synthesis circuit 37. To do. The combination circuit 37 combines the signals input from the F / V conversion circuit 35 and the phase comparison circuit 36, and inputs the signals to the drive circuit 38 and the synchronization detection circuit 39. The drive circuit 38 is a circuit for driving the motor 2 according to the input signal, and the synchronization detection circuit 39 is a circuit for detecting whether or not the input signal is within a predetermined range, and the result is an information processing control circuit. Enter in 32.

Reference numeral 40 is a comparator for detecting whether or not the output signal of the differential amplifier circuit 10 is within a predetermined level, and the output of the comparator 40 is transmitted to the information processing control circuit 32.

The information processing control circuit 32 is for controlling the switches 11 and 17, the pulse generation circuit 29, and the drive circuit 38 based on signals input from the address counter 30, the synchronization detection circuit 39, and the comparator 40.

 The rotation control of the motor 2 will be described.

When the information processing control circuit 32 transmits a motor rotation ON command to the drive circuit 38, the drive circuit 38 controls the motor 2 to rotate. When the motor 2 starts to rotate, the frequency generator 33 generates a signal having a frequency corresponding to the rotation speed, and this signal is waveform-shaped by the waveform shaping circuit 34 and then the F / V conversion circuit 35 responds to the frequency of the signal. Converted to voltage. Further, the phase comparison circuit 36 uses the signal from the waveform shaping circuit 34 and the reference frequency generation circuit 31.
Generates a signal according to the phase difference of the signal of
The signal of the V conversion circuit 35 and the signal of the phase comparison circuit 36 are combined and added to the drive circuit 38. The drive circuit 38 controls the rotation of the motor 2 according to the input voltage.

Therefore, the motor 2 is controlled so that the frequency of the signal generated by the frequency generator 33 and the frequency of the signal of the reference frequency generation circuit 31 have a constant relationship, so that the motor 2 rotates at a predetermined rotation speed. When the motor 2 rotates at a predetermined rotation speed, the output voltage of the synthesizing circuit 37 becomes a predetermined value, and the synchronization detection circuit 39 informs the information processing control circuit 32 that the motor is rotating at the predetermined rotation speed.

Next, tracking control will be described. Photo detector 9
Has a two-division structure, and the direction of the division line is the same as the track direction of the track pattern included in the light beam 4 reflected from the recording disk 1. The respective signals of the photodetector 9 are input to the differential amplifier 10, and the differential amplifier 10 amplifies and outputs the difference between the respective signals. Information processing control circuit
When 32 turns on the switch 11, the output of the differential amplifier 10 is applied to the tracking element 21 via the switch 11, the synthesizing circuit 12, the phase compensation circuit 18, and the driving circuit 20, and the tracking element is moved in the radial direction of the recording disk 1. The light beam is controlled so that it always scans over the track. This control is called tracking control. Further, the signal of the synthesizing circuit 12 is transmitted to the linear motor 23 via the phase compensating circuit 19 and the drive control circuit 22, and the linear motor 23 transfers the transfer table 25 in the radial direction of the recording disk 1 to drive the differential amplifier 10. The transfer is controlled so that the output becomes zero on average, that is, the tracking element 21 moves around the natural state. The signal from the speed detector 24 that detects the moving speed of the transfer table 25 is input to the drive control circuit 22.
The drive control of 23 is more stable.

FIG. 2 shows a concrete circuit of the pulse generation circuit 29 and the address counter 30 of FIG. 1. The signal (line MST) output from the information processing control device 32 of FIG. 1 is a flip-flop. The binarization circuit 28 is connected to the set terminals of 41 and 42.
The signal (line R) output from the flip-flops 41,4
To the clock terminal of 2 and the reset terminal of the counter 43,
The signal (line CK) output from the reference frequency generation circuit 31 is connected to the clock terminal of the counter 43, respectively. The D terminal of the flip-flop 41 is connected to GND, the Q terminal is connected to the D terminal of the flip-flop 42, and the AND circuit 44 is connected.
, The Q terminal of the flip-flop 42 to the AND circuit 44,
The output of the AND circuit 44 is to the AND circuit 45 and the information processing control circuit 32, the output of the AND circuit 42 is to the reset terminal of the counter 46, the Q ₁ terminal of the counter 43 is to the AND circuit 46 and the NOR circuit 47, and the Q ₂ terminal is AND circuit 46 and NOR circuit 47
The output of the AND circuit 46 is connected to the AND circuit 45, respectively. The output signal of the AND circuit 45 (line WE) is RA
To M15, the output signal of Noa circuit 47 (line S / H) for A / D conversion circuit 14, the signal of Q ₃ to Q ₈ of the counter 43 (line ADR) is RAM15
And the information processing control circuit 32, respectively.

FIG. 3 shows a concrete circuit of the comparator 40 shown in FIG.
The signal (V _i ) input from the differential amplifier circuit 10 in FIG. 1 is connected to the + terminal of the comparator A and the-terminal of the comparator B. The-terminal of the comparator A is connected to the power supply V _CC via the resistor R ₁ and the + terminal of the comparator B is connected via the resistor R _2.
It is connected to the terminal and the resistor R _3, and is connected to the power supply V _SS via R ₃ . The outputs of the comparator A and the comparator B are connected to the base of the transistor Q ₁ and the cathode of the diode D ₁ via resistors R ₄ and R ₅ , respectively. The cathode of the diode D ₁ and the emitter of the transistor Q ₁ are connected to GND, the collector is connected to V _CC through the resistor R _6, and to the information processing control circuit 32 of FIG.

The signal V _i input from the differential amplifier circuit 10 in FIG. At this time, the outputs of the comparator A and the comparator B are both at the “LOW” level, and the output (V _o ) of the transistor Q ₁ is at the “HIGH” level.

Further, the signal V _i input from the differential amplifier circuit 11 in FIG.
But Of time, the output of the comparator A becomes the "HIGH" level, transistor Q ₁ is ON and output (V _o) is the "LOW" level.

In addition, the signal V _i input from the differential amplifier circuit 11 in FIG.
But Of time, the output of the comparator B becomes the "HIGH" level, transistor Q ₁ is ON and output (V _o) is the "LOW" level.

Next, the operation of storing the signal of the tracking control system in the storage means and then adding the signal of the tracking control system stored in the storage means to the tracking control system will be described.

When the information processing control circuit 32 outputs an operation command to the drive circuit 38 and the switch 11, the motor 2 rotates at a predetermined speed and then tracking control operates. In this state,
When the information processing control circuit 32 outputs a "HIGH" level storage start signal (line MST) to the pulse generation circuit 29, the signal of the one-rotation detector 26 generates a pulse via the waveform shaping circuit 27 and the binarization circuit 28. At the moment when it is input to the circuit 29, the output of the flip-flop 41 changes from the “LOW” level to the “HLGH” level. Therefore, the output of the AND circuit 44 becomes "HIGH" level. The counter 43 counts the signal (line CK) input from the reference frequency generation circuit 31 after all the outputs of Q _{1 to} Q ₈ are cleared by the signal of the binarization circuit 28 (line R) and generates a pulse. The circuit 29 outputs a signal (line WE) to the RAM 15.

Further, the address counter 30 transfers the sample hold signal (line S / H) to the A / D conversion circuit 14 and the address signal (AD
R) is output to the RAM 15 and the information processing control circuit 32.

FIG. 4 shows an operation waveform diagram of each of the above parts. 4A is an output signal of the binarization circuit 34 (line R), and B is a signal input from the information processing control circuit 32 to the pulse generation circuit 29 (line MS).
T), C is an output signal of the AND circuit 44 (line WR), D is a signal input from the address counter 30 to the A / D conversion circuit 14 (line S / H), and E is an input signal from the pulse generation circuit 29 to the RAM 15. RAM15 from the address counter 30 for the signal (line WE)
Is a signal (line ADR) input to.

The A / D converter circuit 14 samples the analog signal input from the low-pass filter 13 when the signal (line S / H) input from the address counter 30 becomes "HIGH" level, and synchronizes when it holds it when it becomes "LOW" level. A / D conversion is carried out and a digital signal corresponding to the magnitude of the inputted analog signal is inputted to the RAM 15. The RAM 15 receives the signal (line ADR) input from the address counter 30 from the A / D conversion circuit 14 at the address of the signal (line ADR) input from the address counter 30 when the signal (line WE) input from the pulse generation circuit 29 becomes "HIGH" level. Store the digital signal. Then address counter 30
Counts up when the signal of the reference frequency generation circuit 31 is input. Signal of pulse generator circuit 29 (line WE)
And the signal of the address counter 30 that counts the signal of the reference frequency generation circuit 31 (line ADR) are synchronized, and the address counter 30 counts up after the signal of the pulse generation circuit 29 (line WE) is output. are doing.

Most of the signals of the tracking control system are components synchronized with the rotation of the motor 2, especially the rotation components of the motor 2, and when the switch 11 is ON and the switch 17 is OFF and tracking control and transfer control are operating. Since the loop gain of the tracking control system is not sufficient due to the eccentricity of the recording disk 1, the eccentricity of the shaft of the motor 2, and the like, the light beam 4 cannot sufficiently follow a predetermined track on the recording disk 1 and a track deviation occurs. A signal (mainly a component synchronized with the rotation cycle) corresponding to the track deviation is generated in the dynamic amplification circuit 10. The track shift signal of the differential amplifier circuit 10 is stored in the RAM 15 via the switch 11, the low-pass filter 13, and the A / D conversion circuit 14. Next, the signal of the single rotation detector 26 is a waveform shaping circuit 27,
When input to the pulse generation circuit 29 and the address counter 30 via the binarization circuit 28, the pulse generation circuit 29 is changed to the RAM 15
The write signal (line WE) that was input to is stopped.

The output of the AND circuit 44 of the pulse generation circuit 29 changes from "HIGH" to "LOW" level, and the write signal (line WE) input to the RAM 15 is stopped.

The output of the AND circuit 44 of the information processing control circuit 32 is "HIGH".
At the time of level, it is detected whether or not the signal input from the comparator 40 is always at "HIGH" level. When the AND circuit 44 is at the "HIGH" level, that is, when the RAM 15 is in the storage state, the tracking control is disturbed when the disk dust, dirt, or external vibration or shock is applied to the device, and the differential amplifier circuit 10 has a large track. A shift signal is generated. This track deviation signal is input to the comparator 40, and the comparator 40 receives the input track deviation signal (V _i ). Or When, the signal of “LOW” level is output.

When the signal input from the AND circuit 44 is at the “HIGH” level and the signal input from the comparator 40 is at the “LOW” level, the information processing control circuit 32 determines that an abnormal signal has been stored in the RAM15, and the RAM15 In order to memorize the tracking control system signal again in the pulse generator circuit 29, "LOW""HIG
The H "pulse signal (line MST) is output. Then, the tracking control system signal is stored in the RAM 15 in the same manner as described above. Here, when the output of the AND circuit 44 is at the" HIGH "level again (RAM 15 is in the storage state). Information processing control circuit 32 switches 11 and 12 and drive circuit 38 to stop the operation of the device.
The command signal is output to.

When the output of the comparator 40 is always at the "HIGH" level when the RAM 15 is in the storage state, the information processing control circuit 32 normally stores the signal of the tracking control system digitally in synchronization with the rotation of the motor 2. To confirm.

Next, the operation of reading the signal stored in the RAM 15 will be described.

When the signal (WE) of the pulse generation circuit 29 becomes "LOW" level, the RAM 15 is in a read state. Address counter 3
0 is cleared every time a signal (line R) is input from the binarization circuit 28, and when the signal (line CK) of the reference frequency generation circuit 31 is input, it counts up and the output of the counter The signal (line ADR) is input to the RAM 15 as an address signal. Therefore, the RAM 15 can repeatedly read the digital signal in synchronization with the rotation of the motor 2.
When the information processing control circuit 32 turns on the switch 17, the digital signal read from the RAM 15 is input to the D / A conversion circuit 16 for converting into an analog signal, and the D / A conversion circuit 16 converts the converted analog signal. The signal is input to the combining circuit 12 via the switch 17, and the combining circuit 12 combines the signal of the switch 11 and the signal of the switch 17 and inputs them to the phase compensation circuits 18 and 19, respectively. As a matter of course, when the switch 17 is OFF, the D / A
The signal level of the conversion circuit 16 is set to be substantially the same as the signal level of the differential amplifier circuit 10.

When the signal from the D / A conversion circuit 16 is applied to the tracking control system, the light beam 4 moves so as to substantially follow the eccentricity of the recording disk 1, so that the signal from the differential amplifier circuit 10 is synchronized with the rotation of the motor 2. The component becomes extremely small.

As described above, according to the present invention, when the signal of the tracking control system is stored in the RAM, the tracking control is disturbed if scratches, dirt on the recording coarse body or vibrations are applied to the device. This disturbing signal of the tracking control system is compared with a predetermined value by a comparator, and if it is a predetermined value or more, the signal of the tracking control system is stored again in the RAM,
By storing the signal of the tracking control system in the RAM when the stable tracking control is performed and adding the stored signal to the tracking control system, the stable and highly accurate tracking control can be performed.

EFFECTS OF THE INVENTION The present invention has been described above. By applying the present invention, it is possible to prevent the tracking control from becoming unstable even if vibration, shock, or noise is applied to the apparatus, and to provide a highly reliable information recording apparatus. Can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of an information recording / reproducing apparatus according to the present invention, FIG. 2 is a concrete circuit diagram of a pulse generating circuit and an address counter in FIG. 1, and FIG.
A concrete circuit diagram of the comparator in the figure, and FIG. 4 is a timing waveform diagram for explaining the operation of FIG. 1 ... Recording disk, 2 ... Motor, 15 ... RAM, 26 ... 1
Rotation detector, 29 ...... pulse generation circuit, 30 ... address counter, 32 ... information processing control circuit, 40 ... comparator.

Claims (2)

(57) [Claims] 1. A rotating means for rotating a disk-shaped record carrier having a track, a signal converting means for reproducing or recording a track on the record carrier, and a scanning position of the signal converting means is the record carrier. Tracking control means for controlling to be positioned on the upper track, storage means for storing the signal of the tracking control means, and track deviation for detecting that the scanning position of the signal conversion means is deviated from the track on the record carrier. A detection means, and while storing the signal of the tracking control means in the storage means,
An information recording / reproducing apparatus characterized in that, when the track deviation detecting means operates, the signal of the tracking control means is stored again in the storage means. 2. The apparatus according to claim 1, wherein the operation of the apparatus is stopped when the track deviation detecting means operates while the signal of the tracking control means is being stored in the storage means. The information recording / reproducing apparatus as described in the item.