JPH0836760A - Disk apparatus - Google Patents

Abstract

PURPOSE:To perform a stable tracking pull-in by detecting external vibration even when the tracking servo of a disk apparatus is opened. CONSTITUTION:The change of a tracking error signal A due to the eccentricity of an optical disk 1 or an external vibration is turned into pulse by a comparator 6. In this case, first and second pulse interval detecting means 7, 8 set the output of the comparator 6 to 'H' and input it to an MPU 9 when it is shorter than a set time T1 and longer than a set time T2. The MPU 9 detects that the vibration is applied, and controls a tracking servo changeover switch 10. Since the MPU 9 can measure the time when the input signal becomes 'H', it operates as pulse width detecting means for detecting that the Q output of a D flip-flop 7b of the first means 7 becomes the set time 'H'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk device having a random access function such as CD, MD (mini disk) and magneto-optical disk.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing the structure of a conventional disk device. In FIG. 3, reference numeral 1 is an optical disk, which is rotated by a spindle motor 2. An optical pickup 3 is moved by the traverse motor 4 in the radial direction (arrow ab) of the optical disk 1, and its output signal is input to the RF matrix amplifier 5.
The output A of the RF matrix amplifier 5 is a tracking error signal, which is input to the tracking servo control unit 11 and the vibration detection circuit 15, respectively. Also, the RF
The other output B of the matrix amplifier 5 is a focus error signal, which is input to the focus servo control unit 12.

The output of the vibration detection circuit 15 is input to the tracking servo control section 11. The output of the tracking servo control unit 11 is input to the driver 14 and the traverse motor control unit 13. Output of focus servo control unit 12 and traverse motor control unit
Both outputs of 13 are input to the driver 14. The output of this driver 14 is an amplified version of the input signal,
The output C drives the traverse motor 4, the output D drives the focus actuator (not shown) of the optical pickup 3, and the output E drives the tracking actuator (not shown) of the optical pickup 3. .

FIG. 4 shows a circuit diagram of the vibration detecting circuit 15 shown in FIG. 3, and its operation timing chart is shown in FIG. The input signal TE is a bandpass filter (hereinafter referred to as BPF)
The signal passes through 15-1 and is input to the comparators 15-2 and 15-3, and the comparison outputs of the two comparators are input to the OR circuit 15-4.

Next, the operation of the conventional example shown in FIG. 3 will be described with reference to the operation timing chart of FIG. In FIG. 3, when the focus and tracking loops are closed, the output A of the RF matrix amplifier 5 is at a substantially constant level, but when vibration exceeding the suppression level is applied from the outside in the tracking direction, an error is added to the servo loop. The tracking error signal of the output A of the RF matrix amplifier 5 changes according to the external vibration. This signal
(TE in FIG. 5) is input to the vibration detection circuit 15, and B in FIG.
The signal in the required band is extracted by the PF 15-1 and input to the comparators 15-2 and 15-3 which form a window comparator.
When the output of the BPF 15-1 exceeds the threshold V _{TH +} of the window comparator or becomes V _TH- or less as shown in FIG. 5, the output OUT of the OR circuit 15-4 becomes “H”.

As described above, if the thresholds of the comparators 15-2 and 15-3 forming the window comparator are appropriately selected, it can be detected that the vibration exceeding the specified value is applied in the tracking direction from the outside. In FIG. 3, the output of the vibration detection circuit 15 is input to the tracking servo control unit 11 to switch the gain intersection to a high frequency, thereby improving the suppression level against external vibration and stabilizing it against external vibration. A tracking servo loop can be constructed.

[0007]

However, in the above-mentioned conventional disk device, when the tracking loop is opened, the optical spot from the optical pickup 3 crosses the track due to the eccentricity of the optical disk 1 or the like, so that the track error signal has the maximum amplitude. However, there is a problem that external vibration in the tracking direction cannot be detected.

The present invention solves such a conventional problem, and even when the tracking loop is opened,
It is an object of the present invention to provide a disk device which detects vibrations applied from the outside in the tracking direction and has improved stability during tracking pull-in.

[0009]

In order to achieve the above object, the present invention provides a pulse when a track error signal exceeds a set threshold level or crosses. And a first pulse interval detecting means for detecting that the pulse width is equal to or less than a set time interval, and a microprocessing for detecting an external amplitude from an output of the first pulse interval detecting means. Means is provided so that external vibration can be detected even when the tracking loop is opened.

According to a second aspect of the invention, in addition to the comparator,
The microprocessing means is provided with pulse width detection means for detecting that the output of the first pulse interval detection means continues to be generated for a certain period of time or more so that external vibration can be detected even when the tracking loop is opened. It is the one.

According to a third aspect of the present invention, in addition to the first aspect of the invention, there is provided a second pulse interval detecting means for detecting that the output pulse width from the comparator is equal to or longer than a set time interval. Even when the tracking loop is provided and the tracking loop is opened, the vibration from the outside can be detected and also the portion where the vibration from the outside is weak can be detected.

[0012]

Therefore, according to the first aspect of the present invention, the tracking error signal when the tracking loop is opened can be pulsed through the comparator, and it can be detected that the pulse interval is below a certain setting. In a disk device that uses an optical pickup or the like that is not mass-balanced in the tracking direction, when a certain range of external vibration is applied, tracking at a frequency higher than the maximum value of the frequency of the tracking error signal caused by disk eccentricity and access operation is performed. Since an error signal is generated, vibration from the outside can be detected by appropriately selecting the pulse interval to be detected.

According to the second aspect of the present invention, it is possible to detect that the duration time when the pulse duration is equal to or less than the set pulse interval is equal to or longer than a certain setting, so that malfunction due to noise or the like can be prevented.

According to the third aspect of the present invention, it is possible to detect the vibration from the outside and also detect that the tracking error signal has become equal to or lower than the set frequency, so that it is possible to know the time point advantageous for the tracking pull-in.

[0015]

1 is a block diagram showing the configuration of an embodiment of the present invention. In FIG. 1, reference numeral 1 is an optical disk, which is rotated by a spindle motor 2. An optical pickup 3 is moved by the traverse motor 4 in the radial direction (arrow ab) of the optical disk 1, and its output signal is input to the RF matrix amplifier 5. This R
The output A of the F matrix amplifier 5 is a tracking error signal, which is input to the newly provided comparator 6 and tracking servo opening / closing switch 10.

The output of the comparator 6 is a first pulse interval detecting means 7 for detecting that the pulse interval has become T ₁ or less.
Is input to The first pulse interval detecting means 7 is composed of a retriggerable one shot 7a having a pulse width T ₁ and a D flip-flop 7b. Further, the output of the comparator 6 is inputted to the second pulse interval detecting means 8 which detects that the pulse interval becomes T ₂ or more. The second pulse interval detecting means 8 is composed of a retriggerable one shot 8a having a pulse width T ₂ and a D flip-flop 8b.

The output of the retriggerable one shot 7a of the first pulse interval detecting means 7 is connected to the D input terminal of the D flip-flop 7b. The output of the comparator 6 is connected to the T input terminal of the D flip-flop 7b. The output of the retriggerable one-shot 8a of the second pulse interval detecting means 8 is connected to the D input terminal of the D flip-flop 8b. The comparator 6
Is connected to the T input terminal of the D flip-flop 8b. The Q output of the D flip-flop 7b is
I of micro processing unit (hereinafter referred to as MPU) 9
It is input to the N1 terminal,

[0018]

[Outside 1]

The tracking servo open / close switch 10 is M
It is opened and closed by the output from the OUT1 output terminal of PU9. The output of the tracking servo open / close switch 10 is input to the tracking servo control unit 11, and the output thereof is input to the driver 14 and the traverse motor control unit 13.

On the other hand, the output B of the RF matrix amplifier 5
Is a focus error signal, which is input to the focus servo control unit 12, and the output of this focus servo control unit 12 is input to the driver 14. Also, the driver 14
The output of each is an amplification of each input, the output C drives the traverse motor 4, and the output D is the optical pickup 3
Drive the focus actuator (not shown). Also,
The output E is configured to drive a tracking actuator (not shown) of the optical pickup 3.

Next, the operation of the embodiment shown in FIG. 1 will be described with reference to the operation timing charts of the first and second pulse interval detecting means 7 and 8 shown in FIG. If the tracking servo open / close switch 10 is opened while the focus servo and the tracking servo are closed, the tracking servo is turned off, and the RF signal becomes RF as shown in (a) of FIG.
The tracking error signal of the output A of the matrix amplifier 5 changes due to the eccentricity of the disk and the vibration from the outside. At this time, the output of the comparator 6 becomes as shown in FIG.

Here, if the pulse width T ₁ of the retriggerable one-shot 7a that constitutes the first pulse interval detecting means 7 is properly selected, the tracking error will occur only when an external signal with a frequency and strength within a certain range is applied. Since the part where the frequency of the signal A becomes high occurs, a pulse shorter than the set time T ₁ occurs in the output pulse interval of the comparator 6, and as shown in (c) of FIG. The output of 7a is retriggered.

As a result, the Q output of the D flip-flop 7b becomes "H" when the pulse interval of the output of the comparator 6 becomes T ₁ or less as shown in (d) of FIG. Since the Q output of the D flip-flop 7b is connected to the IN1 terminal of the MPU 9, the MPU 9 can detect that external vibration is applied.

Further, since the time when the input signal is "H" can be measured by the MPU 9, pulse width detecting means for detecting that the Q output of the D flip-flop 7b has been "H" for a certain set time or longer. To work as.

Next, if the pulse width T ₂ of the triggerable one-shot 8a constituting the second pulse interval detecting means 8 is properly selected, even when an external vibration of a certain range of frequency and strength is applied, it can be partially since the frequency of the tracking error signal a is low, in the output pulse interval of the comparator 6 generates those longer than the set time T _2, as shown in the FIG. 2 (e).

When the input pulse interval is longer than the set time T _2, it is not retriggered,

[0027]

[Outside 2]

As described above, according to the present embodiment, even when the tracking servo is opened, the tracking error signal A is pulsed by the comparator 6 to indicate that external vibration having a frequency and strength within a certain range is applied. This has the effect that it can be known by the fact that the pulse interval has become less than a certain set time. Further, even if the pulse interval is less than a set time, if the duration is less than a set time, the pulse width detecting means ignores the error, thereby preventing malfunction due to noise or the like.

Further, since it is possible to detect that the pulse interval has exceeded a set time, there is an effect that it is possible to know a time point advantageous for tracking pull-in.

[0030]

As described above, the disk device of the present invention can detect that external vibration is applied from the tracking error signal even when the tracking servo is opened. Further, even if noise or the like is mixed in the tracking error signal, if the detection signal does not continue for a certain set time or longer, it can be ignored to prevent malfunction.

Furthermore, it is possible to know from the tracking error signal a time point at which external vibration is relatively weak and which is advantageous for tracking pull-in.

[Brief description of drawings]

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

FIG. 2 is an operation timing chart of the first and second pulse interval detecting means in FIG.

FIG. 3 is a block diagram showing a configuration of a conventional disk device.

FIG. 4 is a vibration detection circuit diagram of the disk device shown in FIG.

5 is an operation timing chart of the vibration detection circuit of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Spindle motor, 3 ... Optical pickup, 4 ... Traverse motor, 5 ... RF matrix amplifier, 6 ... Comparator, 7 ... 1st pulse interval detection means, 7a, 8a ... Retriggerable one shot, 7b , 8b ... D flip-flop, 8 ... Second pulse interval detecting means, 9 ... MPU, 10 ... Tracking servo opening / closing switch, 11 ... Tracking servo control section, 12 ... Focus servo control section, 13 ... Traverse motor control section, 14 …driver.

Claims (3)

[Claims] 1. A level of a track error signal obtained by a light spot from an optical pickup crossing a track of an optical disc is compared with a threshold level, and the track error signal exceeds the threshold level. Alternatively, a comparator that generates a pulse when crossed, a first pulse interval detection means that detects that the interval between the pulses output from the comparator is less than or equal to a certain time interval T ₁ , and the first A disk device comprising: microprocessing means for detecting external vibration based on the output from the pulse interval detection means. 2. The microprocessing means comprises pulse width detection means for detecting that the output of the first pulse interval detection means has occurred continuously for a certain time or longer. The disk device described. 3. The second pulse interval detecting means for detecting that the interval of pulses from the comparator has become a certain time interval T ₂ or more, according to claim 1 or 2. Disk device.