JPH0386967A - Optical disk player - Google Patents

Abstract

PURPOSE:To enhance the reproducible allowability by accelerating the disk reproducing speed at high speed and shortening the time for tracing a drop-out part of the disk with an optical pickup when information of a table of contents cannot be read out. CONSTITUTION:The optical disk player is provided with a reproducing speed changeover control means 16 for changing the reproducing speed of the disk 1 over to a high speed when it is detected that the information of the table of contents is not read out by a TOC (table of contents) read-out detecting means 15 after a prescribed time from the commencement of regenerating a TOC signal. By this method, when the TOC information of the disk cannot be read out, the time for tracing the drop-out part of the disk 1 with the optical pickup 3 is shortened by accelerating the reproducing speed of the disk 1 at a high speed, thus enhancing the reproducible allowability.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Industrial Application Field The present invention has main data such as audio information recorded on the disc after reproducing a table of contents signal serving as table of contents information recorded on the disc. Regenerates the main signal,
The present invention also relates to an optical disc player in which the disc playback speed can be switched from a standard speed to a higher speed than the standard, and particularly relates to an optical disc player that is devised for reading the table of contents information.

(Example) Conventional technology An optical disc player is known that uses an optical pickup to optically reproduce signals recorded on a disc.A typical optical disc player is a C
D players are known, but some CD players include
For example, as shown in Japanese Unexamined Patent Application Publication No. 1-98164, there is a device in which the playback speed of a disc (CD) can be switched to a high speed faster than the standard, in addition to the standard one. Such a CD player can be combined with a tape recorder capable of high-speed recording at the same ratio as the high-speed playback speed standard, that is, a CD player capable of double-speed playback can be combined with a tape recorder capable of double-speed recording. By combining these, it is possible to perform dubbing in a short time by recording the reproduced signal reproduced by a CD player with a tape recorder.

By the way, as is well known, CD players use TO, which is table of contents information used for signal searches such as song selection and display on the display.
After playing back the lead-in area on the innermost circumference of the disc where a table of contents signal called C is recorded, the program area of the disc where main signals such as audio information and other main data are recorded is played back. It is configured.

(C) Problems to be Solved by the Invention Incidentally, in an optical disc player, tracking control is performed to make the reading beam from the optical pickup follow the signal track of the disc in order to read the signal. If scratches or fingerprints are left on the disc, a dropout area will often form over a wide range of several to tens of tracks in that area, which may exceed the playback tolerance of the optical disc player. Many optical disc players are configured to stop playback if there is a long dropout section.Therefore, if the dropout section is at the beginning of the disc, there will be no abnormality after that. In particular, with CD players, if the contents of the TOC cannot be read, the main signal cannot be played back, so if the lead-in area of the disc is damaged and the contents of the TOC cannot be read, the disc A problem arose in that even if there were no scratches on the program area of the disc that would interfere with playback, the entire disc could not be played.Furthermore, due to a failure in the clamping operation to press the disc onto the turntable, only the inner circumference of the disc was damaged. It is not uncommon for discs to be scratched, and the same TOC content is repeatedly recorded in the lead-in area of a disc, so even if some TOCs are unreadable due to scratches, there is a possibility that there are still TOCs that can be read. This is despite the fact that it is large.

The present invention aims to provide an optical disc player that has been made in view of the above points.

(2) Means for Solving the Problems The present invention provides an optical disc player in which the disc playback speed can be switched from a standard speed to a higher speed than the standard speed. a table of contents reading detection means for detecting the table of contents; and switching the playback speed of the disc to a high speed when the table of contents reading detection means detects that the table of contents information is not read after a predetermined time after the reproduction of the table of contents signal is started. and a playback speed switching control means for controlling, so that when the table of contents information cannot be read at a standard disk playback speed, the table of contents signal is reproduced again by increasing the disk playback speed.

0> Effect The present invention, when the table of contents information on the disc cannot be read, increases the playback speed of the disc to shorten the time it takes for an optical pickup to trace the dropout part of the disc, thereby increasing the tolerance for playback. That is.

(F) Embodiment FIG. 1 is a circuit block diagram showing an embodiment of the present invention.
1> is a disk (CD), (2) is a spindle motor that rotates the disk (1>), and (3) projects a light beam and receives the light beam reflected by the signal surface of the disk (1). An optical pickup having a photodetector, (4> is an RF amplifier that amplifies the RF signal obtained from the photodetector in the optical pickup (3>) and shapes the waveform, (5> is an RF amplifier for the RF signal obtained from the photodetector in
The optical pickup (3) obtained through the amplifier (4)
> The output signal from the photodetector causes the optical pickup (
Focusing control for converging the light beam (3) onto the signal surface of the disk (1) and tracking control for causing the light beam to follow the signal track on the signal surface, as well as feeding control of the optical pickup (3) itself. (6) is a digital signal processing circuit that performs digital signal processing of the output signal (serial digital signal) generated from the RF amplifier (4) and demodulates various signals; (7) )l The digital signal processing circuit (6
) serves as a storage element for rearranging data when demodulating various signals; PLL circuit for clock regeneration,
(9) is the rotation control of the spindle motor (2) and the RA
a reference clock oscillation circuit that generates a reference clock with crystal oscillation precision used when reading data from M(7);
(10) uses the sub-coding signal demodulated by the digital signal processing circuit (6) to display the display (11), and also responds to the operation of the input means (12) consisting of a key switch. A control circuit composed of a microcomputer that controls various operations using
13> is a D/A converter that converts the digital signal of the main data (audio data) demodulated by the digital signal processing circuit (6>) into an analog signal, and (14) is a D/A converter that is output from the D/A converter (13>). This is an audio circuit consisting of a filter circuit that cuts unnecessary signals from an analog signal and extracts an audio signal, an amplification circuit that amplifies the audio signal, and the like.

By the way, the CD player configured as described above is configured to perform not only standard playback at which the disc playback speed is standard, but also high-speed playback that is faster than standard playback, and when switching between standard playback and high-speed playback, Reference clock oscillation circuit <9)
At the same time, the oscillation frequency of the PLL circuit (
8> and the characteristics of the servo signal processing circuit (5) are switched.

The control circuit (10) also includes a TOC reading detection means <15> for detecting whether or not the TOC has been read when the pasted-in area of the disc (1) is played back;
A playback speed switching control means (16) is provided for controlling the playback speed of the disc to be switched to high speed playback when the TOC reading detection means (15) detects that the TOC has not been read. In particular, the control circuit (10) operates like the broachet shown in FIG. 2 during a TOC reading operation. That is, playback of the lead-in area is started, and at the same time, a timer is started (step ■). Then, the TOC reading detection means (15) detects whether or not the TOC has been read in step (2), and if the TOC has been read, the process moves to a playback control routine (step (2)) of a separate program for controlling playback.

On the other hand, T is detected by the TOC reading detection means (15>).

If it is detected that C is not read, it is determined whether or not the timer time t has passed a preset predetermined time t (step 2), t<1. If so, return to step (2), and if t≧t, proceed to the next step (2). Step ■ is a step that determines whether the current playback speed is standard playback or high-speed playback, and if it is high-speed playback, the playback is stopped (step ■), and if it is standard playback, it is switched to high-speed playback (step ■). ). After switching to high-speed reproduction in step (2), the process returns to step (2) and the lead-in area is reproduced again, and the above-described operations are repeated thereafter.

Next, the operation will be explained using FIG.

When the disk (1) is traced by the light beam projected from the optical pickup (3), the signal recorded on the disk (1) is read by the optical pickup (3), converted into an RF multiplied signal, and sent to the RF amplifier. (4). The RF multiplied signal is amplified by the RF amplifier (4), waveform-shaped, converted into a digital signal, and supplied to the digital signal processing circuit (6). The digital signal processing circuit (6) demodulates the digital signal and extracts various data signals contained in the digital signal.

If the part currently being traced by the light beam is the program area of the disc (1), the main data of the acoustic information (digital audio signal) is extracted by the digital signal processing circuit (6), and the digital audio signal is Again, error correction processing is performed using the error correction data extracted by the digital signal processing circuit (6). At this time, the data is rearranged using the RAM (7). The digital audio signal subjected to error correction processing is supplied to the D/A converter (13), where it is converted into an analog audio signal and converted into stereo left and right channel components. The left and right channel component analog audio signals are separated by the audio circuit (14) to remove unnecessary signal components, and are amplified and supplied to the audio output terminal. (17> and (18)).

Furthermore, if the portion being traced by the light beam is a program area of the disc (1>), the digital signal processing circuit (6) also extracts a subcoding signal from the digital signal output from the RF amplifier (4>). , the sub-coding signal is supplied to a control circuit (10>).

Therefore, the control circuit (10) operates according to the reproduction control data (emphasis on/off, etc.) included in the sub-coding signal, and also operates according to the position index information included in the sub-coding signal. Display (1
1> is displayed.

On the other hand, if the part traced by the light beam is the lead-in area of the disc (1>) that is traced first during playback, the digital signal processing circuit (6> is the RF
The TOC table of contents signal is demodulated from the digital signal output from the amplifier (4). The table of contents signal is transmitted by a control circuit (1
A RAM (not shown) provided in the control circuit (10) so that the TOC information can be used when controlling operations such as music selection performed by operating the input means (12).
is stored in the TOC information, and the display (
11) is displayed.

Note that when the part being traced by the light beam is the lead-in area of the disc (1), there is no digital audio signal supplied from the digital signal processing circuit (6) to the D/A humbator (13), and the audio output is Analog audio signals are never output from terminals (17> and (18>).

As mentioned above, when the TOC information can be read, T.

It is detected that the TOC information has been read by the C reading detection means (15), and a detection signal to that effect is supplied to the reproduction speed switching control means (16). Therefore, the reproduction speed switching control means (16) generates a switching signal for switching the reproduction speed to the standard. Here, the PLL circuit (8) and the reference clock oscillation circuit (9) are set to the standard playback state in which playback is performed at the standard speed in the initial state. Since the in-area is being reproduced, the PLL circuit (8) and the reference clock oscillation circuit (9>) are maintained in the standard reproduction state.

Therefore, thereafter, the portion traced by the light beam moves to the program area of the disc (1), and the program area is reproduced at normal speed.

By the way, the disc (1) has a long dropout section that exceeds the playable tolerance under standard playback conditions.
is formed in the lead-in area of
When the OC reading detection means (15) detects that the TOC cannot be read, the TOC reading detection means (15) outputs a detection signal to that effect.Then, the playback speed switching control means (16) generates a switching signal for switching the playback speed to high speed, and switches the PLL circuit (8) and the reference clock oscillation circuit (9>) to the high speed playback state.

Therefore, the spindle motor (2>) will rotate at a speed that corresponds to the high-speed playback state, and the signal processing speed of the digital signal processing circuit (6>) will also match the high-speed playback state. The characteristics of the servo signal processing circuit (5>) also correspond to the high-speed reproduction state.

Then, playback starts again from the beginning. That is, tracing of the lead-in area is performed in a high-speed playback state.

If the lead-in area is traced in the high-speed playback state, the time required to trace the same dropout area will be reduced compared to that in the standard playback state. Therefore, in the high-speed playback state, there is a high possibility that even if the dropout part exceeds the playable tolerance in the standard playback state, the playback will not be stopped and the dropout part can be exceeded.

The lead-in area is traced in high-speed playback mode,
When the TOC information can be read, the TOC reading detection means
15>, it is detected that the TOC information has been read,
A detection signal to that effect is supplied from the TOC reading detection means (15) to the playback speed switching control means (16). Therefore, the PLL circuit (8) and the reference clock oscillation circuit (9>) are switched to the standard reproduction state by the reproduction speed switching control means (16).

Therefore, after that, the program area of the disc (1>) is played back in the standard manner as usual.

On the other hand, even if the lead-in area is traced in the high-speed playback state, the TOC information cannot be read for more than the predetermined time t6, and the T
When the OC reading detection means (15) detects that the TOC information cannot be read, the control circuit (10) determines that the disc (1) currently being played cannot be played, and the playback is stopped. .

(G) Effects of the Invention As described above, the present invention, when table of contents information on a disc cannot be read due to dropouts, increases the playback speed of the disc to increase the time it takes to trace the dropout portion of the disc with an optical pickup. Since it is shortened, the playability tolerance will be increased, and there is a possibility that the table of contents information that could not be read will be able to be read, and a disc with scratches on the table of contents information may be able to be played. It has the advantage of increasing the

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram showing one embodiment of the present invention, and FIG. 2 is a flowchart for explaining FIG. 1. Explanation of main drawing numbers (2)...Spindle motor, (3)...Optical pickup, (6>...Digital signal processing circuit, (
8)...PLL circuit, (9)...Reference clock oscillation circuit, (lO)...Control circuit, (15>...
TOC reading detection means, (16)...playback speed switching control means.

Claims (1)

[Claims] (1) After reproducing a table of contents signal that is table of contents information recorded on a disk, a main signal having main data such as audio information recorded on the disk is played back, and the table of contents signal and the main signal are Table of Contents reading for detecting whether table of contents information has been read by reproducing the table of contents signal in an optical disc player that reads the table of contents optically using an optical pickup and can switch the disc playback speed from standard to higher than standard. detection means;
Playback speed switching control means for controlling the playback speed of the disc to be switched to a high speed when the table of contents reading detection means detects that the table of contents information has not been read after a predetermined period of time after the playback of the table of contents signal is started. An optical disc player characterized in that, when the table of contents information cannot be read at a standard disc playback speed, the table of contents signal is reproduced again by increasing the disc playback speed.