JPH06168470A - Disk reproducing device - Google Patents

Abstract

PURPOSE:To detect the omission of information and to improve the detection ability of flaws, etc., by generating a defect output signal by adding a morror output signal detected in a detection circuit for the omission of a mirror surface to a detection circuit for the omission of an information surface. CONSTITUTION:The mirror output signal of a detection circuit 6 for the omission of a mirror surface is inputted to a detection circuit 7 for the omission of an information surface and a defect output signal is outputted. When the defect output becomes H, a switching circuit 8 is turned off and makes the servo loop of a disk reproducing device turn off. Consequently, the operating point of a servo driving circuit 9 is set by means of a pre-hold circuit composed of a capacitor C1 holding an operating level just before and a servo loop circuit performs a prescribed servo control. Consequently, since focusing servo or tracking servo operation is exerted, the optical pickup 2 goes excessively out of the track of the disk 1 and the inconvenience such as the long time required for recovering servo operation is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc reproducing apparatus, and more particularly to a disc reproducing apparatus suitable for detecting information loss or scratches on the disc surface to compensate for track jumps.

[0002]

2. Description of the Related Art Conventionally, as a servo loop of a disk reproducing apparatus using an optical pickup, many servo loops shown in the block diagram of FIG. 5 have been provided. In the figure, reference numeral 1 is a disc on which an information signal is recorded, and the recording signal of the disc 1 is an optical pickup 2 (hereinafter referred to as an optical pickup 2
The RF modulated signal is supplied to the signal processing circuit 5 via the RF amplifier 4 and reproduced.

Reference numeral 6 denotes a mirror surface loss detection circuit. The mirror surface loss detection circuit 6 detects from the RF signal that the optical pickup 2 has jumped a recording information track on the disk 1 and outputs a track jump signal. . Reference numeral 7 denotes an information surface loss detection circuit. This information surface loss detection circuit 7 detects information loss on a track and controls a servo drive circuit 9 forming a servo loop to control the tracking servo and focus of the optical pickup 2. Servo etc.

The information plane missing detection circuit 7 of the servo loop of the disc reproducing apparatus having the above-mentioned structure is shown in FIG.
The circuit configuration of was generally used. FIG. 7 is a waveform diagram showing the operation of the information plane missing detection circuit 7 shown in FIG.

In FIG. 6, the voltage applied to the input terminal (IN)
The RF signal (in) is inverted and amplified by a defect amplifier (DEFECT AMP), and this defect amplifier output signal (g) is bottom-held with a long and short time constant via a diode.
The short time constant bottom hold output signal (m) responds to the mirror surface (mirror surface) loss of the disk 1, and the long time constant bottom hold output signal (n) bottom holds the mirror surface level immediately before the loss. This long / short time constant bottom hold output signal (m),
By comparing (n) with the comparator circuit (DEFECT COPARATOR), the information loss detection signal (p) of the mirror surface was output from the output terminal (OUT).

In this way, the information surface loss detection circuit 7 detects the loss of information, and at the time of the detected information loss, the drive of the servo drive circuit 9 of the servo loop is shut off and the optical pickup 2 is picked up.
I had prevented the jump of.

[0007]

However, in the above-mentioned conventional disc reproducing apparatus, the detection function of the information surface missing detecting circuit 7 due to a scratch on the surface of the disc 1 is such that the reproduction output of the optical pickup 2 is deteriorated due to a scratch or the like. Therefore, depending on the shape of the scratch on the disc 1, the scratch is like a mirror surface and the optical pickup 2
However, there is a drawback that the output of the above becomes large and the information loss cannot be detected.

Some simulation disks such as scratches have scratches on the surface of the disk 1 formed on the mirror surface, and information loss such as scratches is detected on the simulation disk formed on the mirror surface. There was also a drawback that you could not do it. As described above, there is a defect that the scratch detection ability is poor for scratches formed on the mirror surface.

The present invention has been made in view of the above points, and its object is to eliminate the drawbacks of the conventional example and to add the output of the mirror surface missing detection circuit 6 to the information surface missing detection circuit 7 In order to provide a disc reproducing apparatus which has a high capability of detecting a scratch or the like by detecting the loss of information.

[0010]

In the disc reproducing apparatus of the present invention, an optical pickup is servo-controlled by a servo loop to run on the disc, and an information loss on the disc is detected by an RF signal reproduced from the optical pickup. In the disc reproducing apparatus having the information surface missing detection means and the mirror surface missing detection means, a mirror output of the mirror surface missing detection means is connected to the bottom hold output of the information surface missing detection means, and a connecting means is provided. A switching control means for interrupting the servo loop by the defect output of the information surface missing detection means and a pre-holding means for pre-holding the servo loop when the servo loop is interrupted by the switching control means are provided, and the mirror surface missing Use the detection signal to detect missing information surface to detect missing disk surface As are those that you configured.

Further, a switching control means for turning on / off the mirror output of the mirror surface loss detecting means by a muting control signal may be provided.

[0012]

According to the present invention, the mirror output signal of the mirror surface missing detection circuit for detecting the lack of the mirror surface on the disk by the RF signal reproduced from the optical pickup is added to the information surface missing detection circuit to detect the information surface missing. The bottom output of the circuit is overlapped with the mirror output signal to obtain a defect output from the information surface missing detection circuit.

When the defect output controls the switching circuit provided in the servo loop for servo-controlling the optical pickup and the information surface loss detection circuit detects the loss of information and the defect output is set to "H level". The switching circuit can be turned off and the servo loop can be cut off.

When the servo loop is interrupted, the servo loop is pre-held by the capacitor C1 connected to the servo loop, and the interrupted servo loop is fixed at the pre-hold level to perform servo control of the optical pickup.

As described above, by superposing the mirror output signal of the mirror surface loss detection circuit on the defect output of the information surface loss detection circuit, scratches on the disk form the mirror surface and the loss of information is conventionally caused. It becomes possible to accurately detect even a flaw that cannot be detected.

In particular, the simulation disk for checking the detection of scratches and the like can also have a more accurate scratch detection ability, and the ability to pass scratches and the like on the disk is improved.

When the mute circuit of the audio reproducing circuit of the disc reproducing device is controlled to be muted ON, the muting control signal becomes "L level", and the muting control signal causes the mirror output signal of the mirror surface missing detection circuit. Is clamped to ground level and the mirror output
Control to OFF.

That is, when the disc reproducing apparatus is operated for searching, the mute circuit is set to ON and the optical pickup is moved in the radial direction of the disc to perform the track jump to search the recorded information on the disc. In this way, when the optical pickup makes a track jump, the servo loop of the optical pickup is interrupted as described above, and the servo control is performed at the pre-hold level, so the optical pickup can be prevented from jumping due to the track jump, and the disc search After that, the reproducing operation can be performed accurately and speedily.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a disc reproducing apparatus according to the present invention will be described with reference to FIGS. The same parts as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted. FIG. 1 is a block diagram of a main part, and FIG. 2 is a mirror surface missing detection circuit 6
And a circuit diagram showing an embodiment of the information surface missing detection circuit 7,
FIG. 3 is a waveform diagram of each part showing the operation of the mirror surface missing detection circuit 6, and FIG. 4 is a waveform diagram of each part showing the operation of the information surface missing detection circuit 7.

In the figure, 8 is a switching circuit for interrupting the servo loop, the switching circuit 8 is switched and controlled by a detection signal of the information surface missing detection circuit 7, and a capacitor C1 is a capacitor forming a pre-hold circuit. . Further, the information plane missing detection circuit 7 is connected as shown in the figure so that the mirror output signal of the mirror plane missing detection circuit 6 is supplied.

The mirror surface missing detection circuit 6 is, for example, as shown in FIG.
A circuit configured as shown in FIG. 3 is generally used, and operation waveforms of respective parts of the mirror surface missing detection circuit 6 will be described with reference to FIG.

The RF signal ("in" waveform in FIG. 3) applied to the input terminal (IN) of the mirror surface missing detection circuit 6 is transmitted to the mirror amplifier (M).
This mirror amplifier output signal is inverted and amplified by IRROR AMP).
(a) is peak-held (b) and bottom-held (c) via the diode. The time constant of the peak hold (b) is set so as to follow the traverse, and the time constant of the bottom hold (c) is set so as to follow the envelope fluctuation of the rotation cycle of the disk 1.

The peak and bottom hold signals (b),
In (c), the envelope signal (d) reproduced by the differential amplifier is obtained, and the level of 2/3 of the peak value of this envelope signal (d) is output from the mirror hold amplifier (e).
The mirror output signal (f) can be output from the output terminal (OUT) by comparing with the mirror comparison circuit (MIRROR COMPARATOR).

That is, the mirror output (f) becomes "L level" on the track of the disk 1, and the space between the tracks (mirror surface)
Then, the output becomes "H level". Also, when the lack of the mirror surface is detected, "H level" is output.

Thus, the mirror output signal (f) of the mirror surface missing detection circuit 6 is output as a track jump signal, while the mirror output signal (f) is the diode D1 and the resistor.
Mirror input terminal (MIR
It is supplied as an input signal (k) to R IN). This mirror input terminal (MIRR IN) is a bottom hold (DEFEC) that operates with a short time constant of the information surface missing detection circuit 7 configured as in the conventional example.
T BOTTOM HOLD) circuit output is connected to the non-inverting input (+) of the capacitor-coupled comparison circuit (DEFECT COMPARATOR).

That is, by adding the input signal (k) generated from the mirror output signal (f) of the mirror surface missing detection circuit 6 to the short time constant bottom hold output signal (h) of the information surface missing detection circuit 7. , The defect output (DEFECT OUT) of the information surface missing detection circuit 7 compares the composite signal of the bottom hold output signal (h) and the mirror input signal (k) with the long time constant bottom hold output signal (i) (DEFECT OUT). It is possible to output the defect output signal (j) that has been compared and processed by the COMPARATOR).

That is, the information surface missing detection circuit 7 is the disk 1
If the mirror output signal (f) becomes "H level" even when the track information lacking of is not detected, the defect output signal (j) of the information surface missing detection circuit 7 becomes "H level" and is output. .

When the switching circuit 8 is constituted by, for example, the transistor Q1 and the FET Q2 as shown in FIG. 2, when the defect output (j) becomes "H level", the transistor Q1
Turns off, and the gate of FET Q2 is also set to a negative voltage by diode D3 and resistor R2, cutting off FET Q2.
That is, the servo loop of the disk reproducing device is cut off by the switching circuit 8, and in the state where this servo loop is cut off, the operating point of the servo drive circuit 9 is set by the pre-hold circuit of the capacitor C1 which holds the immediately preceding operation level. Once set, the servo loop circuit can perform constant servo control.

As described above, since the servo loop is interrupted by the information missing detected by the information surface missing detecting circuit 7 and the detection by the mirror surface missing detecting circuit 6, the focus servo or the tracking servo operation works and the optical pickup 2 is operated.
It is possible to prevent such a problem that the disk greatly deviates from the track of the disk 1 and it takes a long time to restore the servo operation during reproduction.

If the information disc omission detection circuit 7 cannot detect the omission of information when a simulation disc such as a scratch or a scratch on the actual disc 1 forms a mirror surface, the mirror surface omission detection circuit 6 Since the detected loss of the mirror surface is detected and applied to the information surface loss detection circuit 7,
The ability of the optical pickup 2 to detect flaws by the RF signal is improved, the flaw passing ability is increased, the servo loop is cut off, and the servo control by the pre-hold operates, so the playability of the disc player is good. To be demonstrated.

When the disc reproducing device performs an address search operation for recorded data, the optical pickup 2 causes the disc 1
Is moved in the radial direction to perform a track jump operation on the disk 1. Generally, during the search operation, the disk reproducing device controls the mute circuit of the reproducing circuit to mute ON.
Muting is controlled by setting to.

Mirror input terminal (MI) of mirror output signal (f) of output terminal (OUT) of mirror surface missing detection circuit 6 shown in FIG.
RR IN) is connected to the mute circuit 10 via the diode D2 as shown in the figure. Since the output terminal of the mute circuit 10 is set to "L level" when the mute circuit 10 is shutting off the reproduction output of the mute ON, the mirror input terminal (MIRR IN ) Is set to "L level" by the diode D2, the mirror output signal (f) of the mirror surface missing detection circuit 6 is clamped to the ground level, and the output of the mirror output signal (f) is turned off.

That is, since the mirror output signal (f) of the mirror surface missing detection circuit 6 is not superposed on the defect output of the information surface missing detection circuit 7, the mirror surface missing due to the track jump during the search operation of the disk reproducing apparatus is performed. Is not detected.

As described above, when the disc reproducing apparatus performs the search operation, the servo loop operates normally, the target recording data is searched while operating the tracking servo system, and the search recording information is accurately obtained in the tracked state. Can be played on.

On the other hand, when the disc reproducing apparatus is performing the normal reproducing operation, the mute circuit 10 is set to mute OFF, the output terminal of the mute circuit 10 becomes "H level", and the mirror surface missing detection circuit 6 detects it. Mirror output signal
(f) is supplied to the information surface missing detection circuit 7, and the servo loop can be cut off and controlled as described above.

The mirror surface missing detection circuit 6 and the information surface missing detection circuit 7 described above have been described using the commonly used Sony IC: CXA1372. However, the mirror surface missing detection circuit 6 and the information according to the present invention are used. The function of controlling the connection with the surface missing detection circuit 7 and the provision of the switching circuit 8 in the servo loop is not limited to the above-mentioned IC, but can be applied to other ICs or other circuit configurations.

[0037]

As described above, in the disk reproducing apparatus according to the present invention, the mirror output signal (f) detected by the mirror surface missing detection circuit 6 is applied to the mirror input terminal (M
Since the defect output signal (j) is generated in addition to IRR IN), it is possible to accurately detect the loss of information and the loss of the mirror surface due to scratches on the disk 1, improving scratch detection capability, and This has the effect of improving the ability to detect the passage of scratches on the road and obtaining excellent playability of disc reproduction.

Moreover, it has excellent features such as a simple structure and easy implementation because it can be constructed at low cost.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part showing an embodiment of a disc reproducing apparatus according to the present invention.

FIG. 2 is a circuit diagram showing an embodiment of a mirror surface missing detection circuit and an information surface missing detection circuit of the present invention.

FIG. 3 is a waveform diagram showing operation waveforms of respective parts of the mirror surface missing detection circuit.

FIG. 4 is a waveform diagram showing operation waveforms of respective parts of the information surface missing detection circuit.

FIG. 5 is a block diagram of a main part of a conventional example.

FIG. 6 is a circuit diagram of a conventional information surface loss detection circuit.

FIG. 7 is a waveform diagram showing operation waveforms of respective parts of the information surface missing detection circuit of the conventional example.

[Explanation of symbols]

 1 disk 2 optical pickup 3 spindle motor 4 RF amplifier 5 signal processing circuit 6 mirror surface missing detection circuit 7 information surface missing detection circuit 8 switching circuit 9 servo drive circuit 10 mute circuit

Claims (2)

[Claims] 1. An information surface loss detecting means for detecting information loss on the disk by an RF signal reproduced from the optical pickup, wherein the optical pickup is servo-controlled by a servo loop to run on the disk, and a mirror surface loss. In a disc reproducing apparatus having a detection means, the mirror output of the mirror surface missing detection means is overlapped with the bottom hold output of the information surface missing detection means, and the defect output of the information surface missing detection means causes A switching control means for interrupting the servo loop and a pre-holding means for pre-holding the servo loop when the servo loop is interrupted by this switching control means are provided, and the mirror surface missing detection signal is used for the information surface missing detection. Disc playback characterized by being configured to detect surface loss Location. 2. A disk reproducing apparatus according to claim 1, further comprising switching control means for turning on / off the mirror output of said mirror surface missing detection means by a muting control signal.