JPH05174405A - Disk reproducing device - Google Patents

Abstract

(57) [Summary] [Purpose] The present invention relates to a disc reproducing apparatus, and aims to promptly judge a dangerous state such as equipment damage or disc damage caused by an abnormal mounting of the disc. [Structure] The voltage comparison unit 13 compares the tracking voltage and the reference voltage, inputs the voltage comparison result to the microcomputer 14 with a built-in counter, inputs the measurement result of the rotational phase measuring unit 15 to the microcomputer 14, and rotates the disk half a turn. The microcomputer 14 determines the voltage comparison result for a period that is an integral multiple of the period during which the disk mounting state can be detected.

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 for reproducing a signal recorded on a disc such as a compact disc player and a laser disc player by an optical device.

[0002]

2. Description of the Related Art In a disc reproducing apparatus, if a disc mounting state is detected and it is determined to be abnormal, a disc reproducing operation is automatically performed in order to avoid reproduction from being impossible and an abnormal operating state caused by the reproduction. A device for stopping may be provided. In this case, as a detection means usually used, there is a track cross signal generated when the signal reading light crosses between signal recording tracks. A configuration diagram of the detection device using the track cross signal will be described with reference to FIG. 3, and a detection situation will be described with reference to FIG.

In FIG. 3, reference numeral 1 is a disk, 2 is an optical servo section, 3 is a spindle motor, 4 is a rotation phase detecting section of the spindle motor, and 5 is a microcomputer. The microcomputer 5 can control the control of the optical servo unit 2 and the spindle motor 3 by a predetermined algorithm, and the rotation phase detection unit 4 can detect the rotation phase of the spindle motor 3.

The operation of the method for detecting the disc mounted state using the track cross signal in the disc reproducing apparatus having the above components will be described below.

First, the focus is turned on to start the rotation of the spindle. Alternatively, the rotation of the spindle is started and the focus is turned on. At this time, tracking is off. In this state, a track cross signal accompanying the rotation of the disc is detected. Normally, the center of rotation is deviated from the center of rotation, and this eccentric component is generated by a component peculiar to the disc and a component generated at the time of mounting.
This eccentricity component is proportional to the detection amount of the track cross signal generated when the above operation is performed, and is detected with a half rotation of the spindle motor as a cycle. The situation is shown in FIG. 6 is the disc, 7 is the center of rotation of the disc, 8 is the center point of the track of the disc, 9 is the point where the optical pickup is focused, 10 is the deviation between the center of the disc and the center of the track, and 11 is the focus at half rotation. , And 12 is the track width existing on the focus trajectory of 11. Disc 6 is the center of rotation 7
Is rotated around. If the focus is in the on state at nine points in the initial state, the focus traces a locus 11 around the rotation center 7 of the disc on the disc. Since the tracks on the disk are recorded centering on the track center 8 of the disk, the focus shifts the track width 12 due to the track center deviation 10.
However, the track width 12 increases as the center deviation 10 increases. That is, the detected track cross signal increases. Therefore, it becomes possible to determine whether the eccentricity component is within the reproducible range or not, depending on how much the track cross signal is detected. Also,
Since the location where the eccentricity component is maximum is in the direction of the track center deviation 10, there are two locations per rotation of the disk. Therefore, if the track cross signal is detected with the focus being on and the tracking being off for each half rotation of the disk, it is possible to determine whether the center of the disk is abnormally deviated from the center of rotation.

[0006]

However, in the above-mentioned conventional configuration, the track crossing phenomenon occurs due to the vibration of the actuator that executes the tracking servo by controlling in the direction perpendicular to the track due to the external vibration. When the reliability of the cross signal is reduced, the focus is out of focus in the off-track state, or the disc rotation is increased, the track cross signal is not generated, so there is a problem that the judgment may be erroneous or undecidable. Was.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an apparatus for surely detecting the mounted state of a disc by determining the tracking state.

[0008]

In order to achieve this object, the present invention has a configuration including a comparison device for comparing a tracking drive output with a reference value and a device for determining a comparison result of the comparison device. There is.

[0009]

The tracking servo controls the actuator so that the read light passes on the track by operating the actuator in the direction perpendicular to the track. However, the range in which the actuator can operate in the direction perpendicular to the track is limited by the design of the optical system. is there. If the tracking servo is applied beyond this limit, the driving cannot be performed in the driving direction and the driving output becomes abnormal. Therefore, the mounting state of the disc can be determined by comparing the tracking drive output with a reference value by a comparing device and determining whether the tracking drive output is within a normal range. With this configuration, it is possible to reliably determine the mounting abnormality of the disc, and thus it is possible to promptly determine a dangerous state such as damage to the device or destruction of the disc caused by the abnormal rotation of the disc.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 13 is a voltage comparison unit, 14 is a microcomputer with a built-in counter, and 15 is a rotational phase measuring device.

In the apparatus configured as described above, FIG.
The operation will be described using. FIG. 2A shows the tracking drive voltage when the disc is mounted normally and reproduction is possible normally, and FIG. 2B shows the tracking drive voltage when the disc is mounted abnormally and the eccentricity component abnormally increases. FIG. 2 (c) shows the voltage comparison result of the signals of FIG. 2 (a).
2D shows the voltage comparison result of the signals of FIG. 2B.

When the disk is properly mounted and the tracking is normally applied, the tracking drive voltage shows a voltage value within a certain range centered on the tracking offset voltage as shown in FIG. 2 (a). When the eccentricity component is abnormally increased, the movable range of the actuator is limited even if tracking is applied.
The drive voltage becomes abnormally high as shown in (b). Therefore, if the set value of the comparison voltage input to the voltage comparison unit 13 is set so as to be clearly discriminated from the tracking drive voltage of FIG. Can have If the voltage comparison unit 13 is set to output a signal indicating 0 if the tracking drive voltage is higher than the comparison voltage, and a signal indicating 1 if the tracking drive voltage is lower than the comparison voltage, the output of the voltage comparison unit 13 will be normal to the disk. In the case of FIG. 2 (a) in which the disc is mounted, the signal is as in FIG. 2 (c), and in the case of FIG. 2 (d) in which the disc is abnormally mounted, the signal is as in FIG. 2 (d). As a result, FIG. 2 (d)
In this case, a pulse signal is input to the microcomputer 14, and the mounted state of the disc can be determined by the count result of the counter built in the microcomputer 14. When performing the state determination, the point of maximum eccentricity appears twice during one rotation of the disc. Therefore, if the determination is made by the rotational phase measuring device 15 during an integral multiple of the period during which the disc half-rotates, the mounting of the disc The state can be performed reliably and efficiently.

[0014]

As described above, according to the present invention, by providing the voltage comparing means, the disc loading state can be prevented without causing the erroneous determination due to defocusing or vibration which is likely to occur in the detection using the track cross signal. It is possible to realize a judgment function that can make a precise judgment and can promptly avoid the danger caused by the abnormal rotation of the disk due to the abnormal mounting of the disk.

[Brief description of drawings]

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

FIG. 2A is a tracking voltage state diagram when the disc mounting is normal in the embodiment of the present invention. FIG. 2B is a tracking voltage state diagram when the disc mounting is abnormal in the embodiment of the present invention. Output state diagram of the voltage comparison device when the disc mounting is normal in the embodiment (d) Output state diagram of the voltage comparison device when the disc mounting is abnormal in the embodiment of the present invention

FIG. 3 is a block diagram of a device in a conventional example.

FIG. 4 is a plan view for explaining the operation of the eccentricity detection method in the conventional example.

[Explanation of symbols]

 13 Voltage comparison unit 14 Microcomputer with built-in counter 15 Rotational phase measuring instrument

Claims (2)

[Claims] 1. A disk reproducing apparatus comprising: a comparing means for comparing a tracking drive output with a reference value; and a judging means for judging a mounted state of a disk by using an output of the comparing means. 2. A rotation phase detecting means for detecting a rotation phase of a mounted disk, wherein the rotation phase detecting means detects the rotation phase of the disk, and the rotation phase detecting means detects a rotation phase of the disk during an integral multiple of a half rotation period of the disk. The disc reproducing apparatus according to claim 1, wherein the disc mounting state is determined.