JP2000260032A - Optical disk drive - Google Patents

Abstract

(57) [Problem] To provide an optical disk device provided with a detection mechanism capable of clearly distinguishing and recognizing a defect of an optical disk and a shock of the optical disk due to disturbance or the like to prevent erroneous recording. SOLUTION: This optical disk device 30 includes, in addition to the configuration of the conventional optical disk device, a shock detection circuit 32 for detecting external vibration / shock to the optical disk, and at least one of detrack and defocus of the optical head 3. Detection circuit 34 for detecting, detection circuit 32 and detection circuit 34
And a signal processing circuit 36 that processes the detection signal. The detection circuit 32 includes an acceleration sensor 38 and a first comparator 40. The detection circuit 34 includes second and third comparators 44 for comparing the tracking error signal and the focus error signal output from the RF amplifier 7 with predetermined values. The signal processing circuit 46 includes a first latch circuit 48, an inverter 50, and a second latch circuit 5.
2 and an AND circuit 54.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus, and more particularly, to an optical disk apparatus which has high sensitivity to vibrations and disk scratches on the disk, and detects both of them in a discriminative manner to reliably prevent erroneous recording. The present invention relates to an optical disk device described above.

[0002]

2. Description of the Related Art An optical disk device is a device for recording data on an optical disk and reproducing the data recorded on the optical disk. Here, an outline of a configuration of an example of a conventional optical disk device will be described with reference to FIG. The conventional optical disk device 20 basically includes a spindle motor 2 for rotating the optical disk 1, an optical head 3 for irradiating the optical disk 1 with a laser beam at the time of recording / reproducing, a radial direction of the optical disk 1, and a distance from / to the optical disk 1. Optical head 3 in the direction
A biaxial mechanism 4 for displacing the objective lens 3a, a sled mechanism 5 for moving the optical head 3 in the radial direction of the optical disc 1, and a magnetic head 6 for applying a modulated magnetic field to the optical disc 1.

An RF amplifier 7 for outputting required data based on data input from the optical head 3, a servo circuit 9 serving as a feedback control device for the optical head 3, and a function as a control device for the entire optical disc device 20 And a system controller (CPU) 11. The RF amplifier 7 outputs a tracking error signal, a focus error signal, and the like by performing an arithmetic operation on the information supplied from the optical head 3. The servo circuit 9 generates a necessary servo drive signal based on a tracking error signal, a focus error signal, and the like output from the RF amplifier 7 and the system controller 11, and controls the two-axis mechanism 4 and the thread mechanism 5 to perform focus control. And a tracking control, and controls the spindle motor 2 to rotate at a constant angle or a constant linear velocity.

[0004] Further, although not described, the optical disk device 2
0 is the encoder / decoder 8, the address decoder 1
0, a memory controller 12, a RAM 13, a magnetic head driving mechanism 15, and the like.

As described above, in such an optical disk device, the recording area to be magnetized by the magnetic head 6 is determined by the recording laser beam from the optical head. That is, in order to perform appropriate recording along the recording track, it is necessary that the servo circuit 9 accurately performs tracking servo control of the optical head.

By the way, if an external vibration or impact is applied during the recording operation of the optical disk device, the tracking servo of the optical head is released, and a track jump occurs. When a track jump occurs, the optical head moves from a track to be recorded to another track during a recording operation, and data is recorded on another track different from a predetermined regular track. If data has already been recorded on the destination track, that data will be erased by mistake. It should be noted that a set of normal scratches must be recorded correctly to form a set.

Therefore, conventionally, in an optical disk apparatus, a change in the amount of focus light is measured to detect a defect on the optical disk, and when the change in the amount of light is large, it is determined that the optical disk has a defect (scratch). Further, in order to detect a shock (shock) of the optical disk caused by disturbance, a product of a tracking error signal voltage and an off-track signal voltage is detected. When the product is large, it is determined that a tracking error has occurred. Was. Further, as another method, a method has been proposed in which a base unit having a recording head is swingable and its displacement is measured to measure external vibration and impact.

[0008]

However, the conventional defect detection method and shock detection method for an optical disk have the following problems. First, when a shock in the focus direction of the optical head is given to the optical disc,
There is a problem that a signal indicating that a defect has been detected is issued due to a change in the amount of focus light, and a shock is erroneously recognized as a defect. Second, when the defect of the optical disk is large, there is a problem that a tracking error signal is output by erroneously recognizing the off-track, and the defect is erroneously recognized as a shock. In the conventional defect detection method and shock detection method for an optical disk, it is difficult to reliably detect and detect a defect and a shock, and data recording is performed despite occurrence of vibration disturbance. While there is a possibility of performing erroneous recording by doing so, there is a fear that even a minute scratch may be erroneously recognized as the occurrence of vibration disturbance and the data recording may be stopped. Although various methods other than the above-mentioned detection methods have been proposed, none of them is economically and technically satisfactory at present.

It is an object of the present invention to provide an optical disk apparatus having a detection mechanism capable of clearly recognizing a defect of an optical disk and a shock of the optical disk due to disturbance or the like so as to prevent erroneous recording. is there.

[0010]

In order to achieve the above object, an optical disk apparatus according to the present invention records data on an optical disk by an optical head and reproduces the recorded data. A first detection circuit for detecting external vibration / shock; and a second detection circuit for detecting at least one of detrack and defocus of the optical head, wherein the first detection circuit detects external vibration / shock. The recording on the optical disk is stopped by using the detrack signal or the defocus signal output from the second detection circuit as a trigger.

In the present invention, the term "detrack" means a signal indicating that the optical head has deviated from the proper track when the signal value of the tracking error signal is larger than a predetermined value. Defocus (DEFOCUS)
The signal is a signal indicating that it is determined that the optical head is out of focus when the signal value of the focus error signal is larger than a predetermined value.

According to the present invention, the first detection circuit detects external vibration / shock (shock) using, for example, an acceleration sensor, and then the second detection circuit detects a defect (scratch) of the optical disk or a defect caused by the optical disk device itself. When a detrack or a defocus of the optical head to be detected is detected, the recording is interrupted by using the detrack signal or the defocus signal output by the second detection circuit as a trigger, thereby preventing erroneous recording. In other words, the second detection circuit for detecting the defect (scratch) of the optical disk or the detrack or defocus caused by the optical disk device itself by using the detection of the external vibration / shock by the acceleration sensor as a trigger for a predetermined time, for example, 100 msec. , And controls data recording of the optical head based on the detection result.
As described above, in the optical disk device according to the present invention, data recording suspension due to external vibration / shock (shock),
Erroneous recording is prevented by clearly distinguishing data recording continuation due to detrack or defocus caused by a defect (scratch) of the optical disk. When a defect is detected, the recording is continued so as to keep the servo state immediately before and prevent the servo from being dislocated.

In a preferred embodiment of the present invention, the first detection circuit includes an acceleration sensor for detecting an external vibration / shock applied to the optical disk, and a first comparator for comparing an output signal of the acceleration sensor with a predetermined value. And Since the output of the acceleration sensor is 180 degrees ahead of the displacement output detected by the second detection circuit, the data recording is stopped when there is a displacement abnormality after the vibration / shock is detected by the acceleration sensor. Does not cause false recordings.

In a preferred embodiment, the second detection circuit compares the tracking error signal with a predetermined value.
And a third comparator for comparing the focus error signal with a predetermined value. In this embodiment, after detecting an external vibration / shock by the acceleration sensor, the detrack signal or the defocus signal is monitored, and when any of the signals exceeds a predetermined level, data recording is stopped.

In a further preferred embodiment of the present invention, as a circuit for processing detection signals of the first detection circuit and the second detection circuit, a control signal consisting of a pulse signal of a predetermined period is input to a set input terminal. A first latch circuit, an inverter connected to an output terminal of the first latch circuit, a second latch circuit having a set input terminal connected to the output terminal of the inverter, and an input terminal connected to an output terminal of the second latch circuit. An AND circuit to which one of the terminals is connected, an output signal of the first detection circuit is input to a reset input terminal of the first latch circuit, and an output signal of the second detection circuit is output to the second latch circuit. A write / read signal is input to a reset input terminal, and a write / read signal from a system controller for controlling the entire optical disk device is input to the other input terminal of the AND circuit.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically and in detail with reference to the accompanying drawings, taking an example of an embodiment. FIG. 1 is a block diagram showing a configuration of an optical disk device of the present invention, FIG. 2 is a diagram showing a waveform of a control signal, and FIG. 3 is a flowchart showing a signal flow and a processing flow. The optical disk device 30 according to the present embodiment includes an optical disk 1 in addition to the configuration of the conventional optical disk device 20.
, A detrack / defocus detection circuit 34 for detecting at least one of detrack and defocus of the optical head 3, a shock detection circuit 32 and a detrack And a signal processing circuit 36 for processing a detection signal of the defocus detection circuit 34. Shock detection circuit 3
2 is provided with an acceleration sensor (G sensor) 38 for detecting external vibration / impact given to the optical disk 1 and a first comparator 40 for comparing an output signal of the acceleration sensor with a predetermined value. The detrack / defocus detection circuit 34 compares the tracking error signal 45 output from the RF amplifier 7 with a predetermined value.
2 and a third comparator 4 for comparing the focus error signal 46 also output from the RF amplifier 7 with a predetermined value.
4 is provided.

Further, the optical disk device 30 is connected as a signal processing circuit 36 to a first latch circuit 48, an inverter 50 connected to an output terminal of the first latch circuit 48, and an output terminal of the inverter 50. Second latch circuit 52
AND connected to the output terminal of the second latch circuit 52
And a circuit 54.

The first latch circuit 48 and the second latch circuit 52 are registers constituted by, for example, RS flip-flops, and include a set input terminal S, a reset input terminal R, and an output terminal. I have.

The set input terminal S of the first latch circuit 48
, A control signal 56 is input from the system controller 11. On the other hand, the shock detection circuit 32 is connected to the reset input terminal R of the first latch circuit 48, and the output signal of the shock detection circuit 32 is input. The shock detection circuit 32 includes an acceleration sensor 38 and an acceleration sensor 38.
An amplifier for amplifying the output signal of the optical disk 1 and a comparator 40 for generating a low output signal when the output signal exceeds a certain level detect the external vibration / shock applied to the optical disk 1. The acceleration sensor 38 is a sensor that detects an acceleration by measuring an inertial force applied to a mass, detects an acceleration at a predetermined position on the optical disc 1, and outputs a signal.

As shown in FIG. 2, when the signal processing circuit 36 operates, the control signal 56 has a constant period, for example, 100 m.
The signal has a waveform having a rising pulse every second, and the signal processing circuit 36 is refreshed by the rising pulse.

In the first latch circuit 48, a control signal 56
Is low, the output is high even though the output signal is being input from the shock detection circuit 32.

The set input terminal S of the second latch circuit 52
The output signal of the first latch circuit 48 to the inverter 5
An inverted signal inverted by 0 is input. The detrack / defocus detection circuit 34 is connected to the reset input terminal R of the second latch circuit 52, and receives an output signal. The detrack / defocus detection circuit 34 includes a second comparator 42 and a third comparator 44, and when at least one of a focus error signal and a tracking error signal, which are servo signals of the optical head 3, exceeds a certain level. And a comparator circuit for generating a low output signal, and detects the deviation of the tracking servo of the optical head 3.

The output signal of the second latch circuit 52 is input to one input terminal of the AND circuit 54, and the write / read signal 58 from the system controller 11 is input to the other input terminal. The write / read signal 58 is
A signal for controlling recording / reproduction of the optical head, which is input from the system controller 11 of the optical disk device. When the servo is disengaged due to external vibration or impact on the optical disk 1, the output signal of the second latch circuit 52 becomes low (Low), the output of the AND circuit 54 is forced to low (Low), and the recording is interrupted. Switch to playback mode.

Next, referring to FIG. 1, the signal processing circuit 3
6 will be described in further detail. First, when the control signal 56 is low, the signal at the set input terminal S of the first latch circuit 48 becomes low, and the output of the first latch circuit 48 is It is fixed to High regardless of the output. As a result, it is inverted by the inverter 50,
Since the set input of the second latch circuit 52 is low, the output of the second latch circuit 52 is also high regardless of the output of the detrack / defocus detection circuit 34. Fixed. Therefore, the AND circuit 5
As the output of No. 4, the write / read signal 58 is output through.

Next, when the control signal 56 rises,
The first latch circuit 48 becomes operable. Here, when the shock detection circuit 32 detects the external vibration and the output becomes low at that moment, the first latch circuit 48 is set to low. Then, since the rising signal is input to the set input terminal S of the second latch circuit 52, the second latch circuit 52 becomes operable. At this time, the detrack / defocus detection circuit 34 detects detrack / defocus due to external vibration,
At that moment, when the output goes low, the second latch circuit 52 is set low. Then AN
The D circuit 54 outputs a low output, and switches from recording to reproduction. As described above, it is possible to prevent erroneous recording due to servo deviation, which occurs at the time of external vibration or impact on the optical disk 1.

Next, referring to FIG. 3, a description will be given of a signal and a processing flow of the signal processing circuit 36 of the present embodiment. First, in step S _1, as well as to start recording on the optical disk 1, and outputs a control signal 56 from the microcomputer or the like. At the same time, to start the 100msec timer, the process proceeds to step S _2. In step S _2, at the rising edge of the high (High) from the low control signal 56 (Low), the first latch circuit 48 is operable, the process proceeds to Step S _3. In the state of step S _3, when detecting the external vibration by the shock detection circuit 32, the process proceeds to step S _4. When not detected, the process proceeds to step S _7. In step S _4, the output of the first latch circuit 48 becomes low (Low), the signal rise to the set input terminal S of the second latch circuit 52 is input, the second latch circuit 52 is operable , the process proceeds to step S _5.

[0027] In the state of step S _5, the de-track signal from the de-track / defocus detection circuit 34, or de-focus signal is outputted, the output of the second latch circuit 52, is set to a low (Low) Therefore, the AND circuit 5
The output of the 4, shifts the low (Low), and the step S _6. When detrack / defocus detection circuit 34 does not detect both detrack and defocus, the process proceeds to step S _8. In step S _6, it switched from light to lead.

[0028] In the step S _7, the timer is set time 1
Unless 00 msec has elapsed, step S ₃ is repeated.
Return to, when the timer has elapsed the set time 100msec, returns to the step S _1. Step S ₈
So long as the timer has not elapsed the set time 100 msec, the flow returns to step S ₅ again, when the timer has elapsed the set time 100 msec, Step S ₁
Return to That is, in steps S ₇ and S ₈ , when the 100 msec timer overflows during the sequence, the control signal 56 is raised again, and the signal processing circuit 36
Refresh.

In this embodiment, the shock detection circuit 32
Output signal and detrack / defocus detection circuit 34
The relationship between the output signals is as follows. The output signal of the shock detection circuit 32 is the acceleration component of the external vibration / shock, and the output signal of the detrack / defocus detection circuit 34 corresponds to the optical shift generated when receiving the external vibration / shock. . In other words, both output signals have a relationship between acceleration and displacement, and the acceleration always leads the phase by 180 degrees with respect to the displacement.
The detrack / defocus detection circuit 34 can start the detrack / defocus detection using the output signal of the above as a trigger.

The control signal 56 used in the present embodiment generates a rising pulse at a predetermined period, and the rising pulse causes the first latch circuit 48 to generate a rising pulse.
Output is cleared. In other words, even if the external vibration or shock is detected and the second latch circuit 52 is activated, the optical head 3 is not in the detrack state and is not in the defocus state. 48
Clears the output of and detects the next external vibration and shock.

Further, for example, when the optical head 3 is detracked or defocused due to a factor other than external vibration / shock, the following occurs. In the optical disk device 30, recording and reproduction are guaranteed for, for example, scratches of 200 μm or less, depending on the type of the optical disk 1. On the other hand, when data is recorded on the optical disc 1 having a flaw of 200 microns or less, a detrack signal is generated instantaneously even though servo deviation does not occur. In this case, the recording should not be interrupted even if the detrack is detected. In the detrack / defocus detection circuit of the present embodiment, the output of the second latch circuit 52 is high (Hig) when there is no external vibration or shock even if the detrack is detected.
h), the output of the AND 18 remains high, and data recording continues.

In the case where the scratch and the external vibration / shock occur simultaneously, it is not possible to make a correct determination in the prior art, and there is a possibility of erroneous recording by giving priority to the detrack detection processing. In the example, the above-described configuration makes it possible to perform a reliable operation and prevent erroneous recording.

The first and second signal processing circuits 36
The two latch circuits are used to perform signal processing at high speed. Alternatively, the output of the shock detection circuit 32 and the output of the detrack / defocus detection circuit 34 are connected to an interrupt input of the microcomputer by using a microcomputer capable of processing at a sufficiently high speed so that no malfunction occurs. The same control as in the present embodiment can be performed. In this case, the first latch circuit 48, the second latch circuit 52, and the inverter 50 become unnecessary, and the cost can be reduced.

[0034]

According to the present invention, a first detection circuit for detecting an external vibration / shock given to an optical disk and a second detection circuit for detecting at least one of detrack and defocus of the optical head When the external vibration / shock is detected by the first detection circuit, the recording on the optical disc is stopped by using the detrack signal or the defocus signal output by the second detection circuit as a trigger. As a result, detrack detection or defocus detection due to external vibration / shock can be performed, and erroneous recording that occurs at that time can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an optical disk device of the present invention.

FIG. 2 is a diagram showing a waveform of a control signal.

FIG. 3 is a flowchart showing a signal flow and a processing flow.

FIG. 4 is a block diagram showing a configuration of a conventional optical disk device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Spindle motor, 3 ... Optical head, 3a ... Objective lens, 4 ... 2-axis mechanism, 5 ...
... Sled mechanism, 6 ... Magnetic head, 7 ... RF amplifier, 7 ... Encoder / decoder, 9 ... Servo circuit,
10 ... address decoder, 11 ... system controller, 12 ... memory controller, 13 ... RAM,
15 ... magnetic head drive, 20 ... conventional optical disk device, 30 ... optical disk device of embodiment example, 32 ... shock detection circuit, 34 ... detrack / defocus detection circuit, 36 ... signal processing circuit, 38 acceleration sensor, 40 first comparator, 42 second comparator, 44 third comparator, 46 signal processing circuit, 48 first latch circuit, 50 inverter , 52... Second latch circuit, 54... AND circuit, 56... Control signal, 58... Write / read signal.

Claims (4)

[Claims] 1. An optical disk device for recording data on an optical disk by an optical head and reproducing the recorded data, a first device for detecting external vibration and shock applied to the optical disk.
And a second detection circuit for detecting at least one of detracking and defocusing of the optical head, and is output by the second detection circuit when external vibration / shock is detected by the first detection circuit. An optical disc device, wherein recording of data on an optical disc is stopped by using a detrack signal or a defocus signal as a trigger. 2. The method according to claim 1, wherein the first detection circuit includes an acceleration sensor for detecting an external vibration / shock applied to the optical disk, and a first comparator for comparing an output signal of the acceleration sensor with a predetermined value. The optical disk device according to claim 1, wherein: 3. The method according to claim 2, wherein the second detection circuit includes a second comparator for comparing the tracking error signal with a predetermined value, and a third comparator for comparing the focus error signal with a predetermined value. The optical disk device according to claim 1. 4. A circuit for processing detection signals of the first detection circuit and the second detection circuit, a first latch circuit for inputting a control signal composed of a pulse signal of a predetermined period to a set input terminal; An inverter connected to the output terminal of the latch circuit, a second latch circuit having a set input terminal connected to the output terminal of the inverter, and an AND having one of the input terminals connected to the output terminal of the second latch circuit And a circuit for inputting an output signal of the first detection circuit to a reset input terminal of the first latch circuit, inputting an output signal of the second detection circuit to a reset input terminal of the second latch circuit, and ANDs write / read signals from the system controller that controls the entire optical disc device
4. The optical disk device according to claim 2, wherein the signal is input to the other input terminal of the circuit.