JP3141431B2 - Optical disc player - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk reproducing apparatus for reading recorded information from a disk by an optical method.

[0002]

2. Description of the Related Art In recent years, optical disk reproducing apparatuses such as laser disk players have become remarkably widespread.

[0003] A conventional optical disk reproducing apparatus will be described below. FIG. 2 shows a block diagram of a conventional optical disc reproducing apparatus. 2, reference numeral 20 denotes a laser disk, 21 denotes a pickup for reading a signal from the laser disk 20, 22 denotes a video signal demodulation circuit for demodulating a video signal from a signal read by the pickup 21, and 23 denotes an image demodulated by the video signal demodulation circuit 22. A synchronization signal detection circuit for detecting a horizontal synchronization signal from a signal; 24, a synchronization signal generation circuit for generating a horizontal synchronization signal which is a reference for operation of the laser disk player; 25, a time of the video signal demodulated by the video signal demodulation circuit 22; To compensate for typical fluctuations,
A time axis correction circuit 26 whose correction range is within ± (cycle of horizontal synchronization signal / 2) is a laser based on the horizontal synchronization signal detected by the synchronization signal detection circuit 23 and the horizontal synchronization signal generated by the synchronization signal generation circuit 24. A rotation control circuit for controlling the rotation of the disk 20, a rotation drive circuit 27 for rotating the laser disk 20 in accordance with a control signal from the rotation control circuit 26, and a horizontal synchronization signal detected by the synchronization signal detection circuit 23 and a synchronization signal generation circuit 24; The rotation control circuit 26 checks the phase difference with the horizontal synchronization signal generated in
The determination unit 29 determines whether or not the rotation of the laser disk 20 can be controlled within the correction range of 5. The determination unit 29 determines that the rotation control circuit 26 has the laser disk 20 within the correction range of the time axis correction circuit 25. If it is determined that the state has entered the state in which the rotation control of 20 can be performed, the screen switching unit determines that it is possible to display a screen without disturbance.

[0004] The operation of the optical disc reproducing apparatus having the above-described configuration when outputting an image will be described. When switching from the color back screen to the playback screen, the playback screen switching unit 29 checks whether the reading position of the pickup 21 has reached a position on the laser disk 20 at which playback is to be started. Check also. This is because the rotation control circuit 26 can control the rotation of the laser disk 20 within the correctable range of the time axis correction circuit 25 when the reading position of the pickup 21 reaches the position to start reproduction on the laser disk 20 by the access operation. This is because it is not necessarily in the state. If the rotation control circuit 26 is not in a state in which the rotation control can be performed, the reading position of the pickup 21 is slightly moved to the inner peripheral side, so that the rotation control circuit 26 enters a state in which the rotation control can be performed. I need to wait. When the screen switching unit 29 determines that the rotation control circuit 26 has entered the state where the rotation control circuit 26 can perform rotation control, and confirms that the reading position of the pickup 21 has reached the position on the laser disk 20 at which playback is to be started, Switch from the color back screen to the playback screen.

Next, a description will be given of a determination method of the determination unit 28.
FIGS. 3, 4 and 5 show the temporal change of the phase difference between the horizontal synchronization signal detected by the synchronization signal detection circuit 23 and the horizontal synchronization signal generated by the synchronization signal generation circuit 24.
In each figure, H means the I period of the horizontal synchronization signal generated by the synchronization signal generation circuit 24. T1 corresponds to the time required for the laser disk 20 to make about one rotation.
8 is a specific time used for the judgment. As illustrated in FIG. 3, when the determination unit 28 continues the phase difference T1 within ± H / 4, the rotation control circuit 26 enters a state in which the time axis correction circuit 25 controls the rotation of the laser disk 20 within a range that can be corrected. to decide. The time axis correction circuit 25 can correct if the phase difference is within ± H / 2, but even if the phase difference continues within ± H / 2 for T1 as in the case of FIG. The phase difference is ± H /
It may exceed 2. Therefore, the judgment unit 28
Under the condition of H / 4 or less, the phase difference is prevented from exceeding ± H / 2 after the judgment.

[0006]

However, in the above-mentioned conventional configuration, when the amount of eccentricity of the laser disk 20 is large as shown in FIG. 5, the condition of the judging section 28 is not satisfied. Despite the possible range, the screen switching unit 29 has a problem that it does not switch from the color back screen to the playback screen.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to check the state of a rotation control circuit and quickly output a screen.

[0008]

In order to achieve this object, an optical disk reproducing apparatus according to the present invention comprises a synchronizing signal detected by a synchronizing signal detecting circuit and a synchronizing signal generated by a synchronizing signal generating apparatus . The size is within a certain range for more than a certain time
After confirming whether or not the condition has been maintained, and after confirming that the conditions have been satisfied, the rotation control circuit determines that the optical disk has entered a state in which the rotation control of the optical disc can be performed within the correctable range of the time axis correction circuit. And the synchronization signal detection
The sync signal detected by the output circuit and the sync signal
The magnitude of the phase difference with the synchronized signal
Check that the conditions have been met and that the conditions have been met.
After that, the rotation control circuit can correct the time axis correction circuit.
Enters the state where optical disc rotation can be controlled within the range
However, the first determining means is the range of the phase difference to be confirmed.
It has a second judging means which is different from the surrounding time .

[0009]

With this configuration, the phase difference between the synchronization signal detected by the synchronization signal detection circuit and the synchronization signal generated by the synchronization signal generation circuit is confirmed using a plurality of conditions. Less susceptible to eccentricity and scratches on optical discs.

[0010]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an optical disk reproducing apparatus according to an embodiment of the present invention. In FIG. 1, 10 is a laser disk, 11 is a pickup for reading a signal from the laser disk 10, 12 is a video signal demodulation circuit for demodulating a video signal from the signal read by the pickup 11, and 13 is a video signal demodulated by the video signal demodulation circuit 12. A synchronization signal detection circuit for detecting a horizontal synchronization signal from the signal; 14, a synchronization signal generation circuit for generating a horizontal synchronization signal which is a reference for the operation of the optical disc reproducing apparatus; 15, a video signal demodulated by the video demodulation circuit 12; Time fluctuation is corrected and the correction range is ± (horizontal synchronization signal period /
The time axis correction circuit 16, which is within 2), the horizontal synchronization signal detected by the synchronization signal detection circuit 13 and the synchronization signal generation circuit 14
A rotation control circuit for controlling the rotation of the laser disk 10 based on the horizontal synchronization signal generated in the above, a rotation drive circuit 17 for rotating the laser disk 10 according to a control signal of the rotation control circuit 16, and a horizontal drive circuit 18 A detected by the synchronization signal detection circuit 13. The phase difference between the synchronizing signal and the horizontal synchronizing signal generated by the synchronizing signal generating circuit 14 is confirmed, and the rotation control circuit 16 determines whether or not the rotation of the laser disk 10 can be controlled within the correctable range of the time axis correcting circuit 15. The first judging unit 18B judges whether the condition of the phase difference in the first judging unit 18A is a second judging unit different from the condition of the first judging unit 18A. Reference numeral 19 denotes at least one of the first determination unit 18A and the second determination unit 18B.
This is a screen switching unit that determines that an image can be output without any disturbance of the screen if it is determined that the rotation control can be performed.

The operation of the optical disc reproducing apparatus configured as described above when outputting an image will be described. When switching from the color back screen to the playback screen, the playback screen switching unit 19 checks whether the reading position of the pickup 11 has reached a position on the laser disk 10 at which playback is to be started, and also checks the state of the rotation control circuit 16. Check also. The reason is that when the reading position of the pickup 11 reaches a position on the laser disk 10 at which reproduction is to be started by the access operation, the rotation control circuit 16 can control the rotation of the laser disk 10 within the correctable range of the time axis correction circuit 15. This is because it is not necessarily in the state. If the rotation control circuit 16 is not in a state in which the rotation control can be performed, the reading position of the pickup 11 is slightly moved to the inner peripheral side, so that the rotation control circuit 16 enters a state in which the rotation control can be performed. I need to wait. Then, the screen switching unit 19 determines that at least one of the first determination unit 18A and the second determination unit 18B has entered a state where the rotation control circuit 16 can perform rotation control, and the pickup 11
When it is confirmed that the reading position has reached the position on the laser disk 10 where reproduction is to be started, the display is switched from the color back screen to the reproduction screen.

Next, a first judgment unit 18A and a second judgment unit 18
The method of determining B will be described. 3 and 5 show the horizontal synchronization signal detected by the synchronization signal detection circuit 13 and the synchronization signal generation circuit 14.
Shows the temporal change of the phase difference from the horizontal synchronizing signal generated in step (1). 3 and 5 are also used for the description of the conventional example. In each figure, H means one cycle of the horizontal synchronization signal generated by the synchronization signal generation circuit 14. Further, T1 corresponds to the time required for the laser disk 10 to make about one rotation, and is a specific time used by the first determination unit 18A for the determination. Further, T2 is longer than T1, and is a specific time used by the second determination unit 18B for determination. As shown in FIG. 3, when the first determination unit 18 </ b> A continues the phase difference T1 within ± H / 4,
The rotation control circuit 16 determines that the state has entered a state where the rotation of the laser disk 10 is controlled within a range that the time axis correction circuit 15 can correct. Further, as shown in FIG. 5, when the phase difference continues within ± H / 2 for T2, the second determination unit 18B determines that the rotation control circuit 1B
6 judges that the state has entered a state in which the rotation of the laser disk 10 is controlled within a range that the time axis correction circuit 15 can correct.

As described above, according to this embodiment, when the amount of eccentricity of the laser disk 10 is large as shown in FIG. 5, the phase difference does not fall within ± H / 4 and the condition of the first judgment unit 18A is not satisfied. However, the condition of the second determination unit 18B is satisfied. In addition, when the amount of eccentricity of the laser disk 10 is small but the number of scratches is large, the synchronization signal detection circuit 13 cannot partially detect the horizontal synchronization signal. Second discriminating unit 1 that determines based on long time T2
Although the condition is difficult to be satisfied in 8B, the first determination unit 18A that determines in a short time T1 is likely to satisfy the condition. Therefore, the screen switching unit 19 is hardly affected by the eccentricity or scratches of the laser disk 10 and can quickly switch from the color back screen to the reproduction screen.

[0015]

As described above, according to the present invention, the phase difference between the synchronization signal detected by the synchronization signal detection circuit and the synchronization signal generated by the synchronization signal generation circuit is confirmed using a plurality of conditions.
Confirmation of the state of the rotation control circuit is hardly affected by eccentricity, scratches, and the like of the optical disk, and it is possible to quickly switch from the color back screen to the reproduction screen.

[Brief description of the drawings]

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

FIG. 2 is a block diagram of a conventional optical disc reproducing apparatus.

FIG. 3 is a graph showing a temporal change of a conventional phase difference.

FIG. 4 is a graph showing a temporal change of a conventional phase difference.

FIG. 5 is a graph showing a temporal change of a conventional phase difference.

[Explanation of symbols]

 Reference Signs List 10 laser disk 11 pickup 12 video signal demodulation circuit 13 synchronization signal detection circuit 14 synchronization signal generation circuit 15 time axis correction circuit 16 rotation control circuit 17 rotation drive circuit 18A first determination unit 18B second determination unit 19 screen switching unit

Claims (2)

(57) [Claims] A synchronizing signal detecting circuit for detecting a synchronizing signal from a signal read from an optical disc; a synchronizing signal generating circuit for generating a synchronizing signal which is a reference for operation of an optical disc reproducing apparatus; A time axis correction circuit for correcting a temporal variation of a signal read from the disk, a rotation for controlling rotation of the optical disk based on a synchronization signal detected by the synchronization signal detection circuit and a synchronization signal generated by the synchronization signal generation circuit; The magnitude of the phase difference between the control circuit and the synchronizing signal detected by the synchronizing signal detecting circuit and the synchronizing signal generated by the synchronizing signal generator is kept within a certain range for a certain time or more.
After confirming that the conditions have been met,
The rotation control circuit comprises a first determining means for determining that entered the ready to control the rotation of the optical disc by the correction range of the time base correction circuit, wherein similarly to the first determining means
The synchronization signal detected by the synchronization signal detection circuit and the synchronization signal generation
The magnitude of the phase difference from the synchronization signal generated by the
Check if the condition has been maintained for a certain period of time
After confirming that the rotation has been completed, the rotation control circuit
Rotation control of optical disk within the correction range of the axis correction circuit
Is determined to be in a state in which the
Is different from the range and time of the phase difference to be confirmed
And if at least one of the first determining means or the second determining means determines that the rotation control circuit has entered a state in which rotation control of the optical disc can be performed within the correctable range of the time axis correction circuit. An optical disc reproducing apparatus, comprising: a screen switching unit that determines that a screen without disturbance is displayed. 2. A synchronous signal detected by a synchronous signal detecting circuit.
Of the phase difference from the synchronization signal generated by the initial signal generator
To see if it has stayed within a certain range for a certain amount of time,
After confirming that the conditions are met, the rotation control circuit
Rotation control of optical disk within the correction range of the axis correction circuit
Has three or more judgment means to judge that
The range and time of the phase difference to be checked
And a screen switching means that at least one of the plurality of the determination means has entered a state in which the rotation control circuit can control the rotation of the optical disk within the correctable range of the time axis correction circuit. 2. The optical disc reproducing apparatus according to claim 1, wherein if the judgment is made, it is judged that an image can be displayed on the screen without disturbance.