JPH0322222A - Optical disk device - Google Patents

Abstract

PURPOSE:To shorten a time for processing the recording error of information and to record the information at high speed by providing a counter to count a clock signal in a period where a recording signal to modulate light beam is not correspondent to the detecting signal of a photodetector. CONSTITUTION:A detecting signal S3 of an optical sensor 5 goes to a pulse signal S5 by a waveform shaping circuit 6, and is applied to an XOR circuit 12. On the other hand, a recording signal S2 from a recording signal generating circuit 9 goes to a pulse signal S6 by a delay line 7, and is applied to the XOR circuit 12. When the both signals S5 and S6 are obtained, there is no output from the XOR circuit 12, and a DFF 13 does not output the clock signal of an oscillating circuit 10. A counter 16 counts the clock signal to be outputted by the DFF 13, and the count value of the counter is compared with a set value, which is set to a register 11, by a comparator 15. When the count value exceeds the set value, a recording error detecting signal is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical disc device for recording and reproducing information on an optical disc.

[Conventional technology]

When an optical disc device records information by projecting a light beam onto the optical disc, it accesses the address and sector of the position where the information is to be recorded, and records the information there. Thereafter, in order to confirm whether the information has been recorded accurately, after the recording operation is completed, a read process is performed to access the same address and sector again, and it is determined whether or not there is an error in recording the information. If there are few recording errors, the recording operation is completed. On the other hand, if there are many recording errors, the same recorded information is re-recorded at a required position in a required sector.

When recording information in this way, the above-described recording operation is repeated until the recording is completed.

When re-recording information here, even if recording is completed in one re-recording operation, there will be a rotational waiting time during access, a time for one revolution of the optical disc, and a time for one revolution of the optical disc for inspection. This requires a time that is the sum of the re-recording access waiting time, the time for one rotation of the optical disk for re-recording, and the time for checking re-recording, and it takes a long time to process the recording error. Therefore, the time required for recording error processing is shortened by increasing the rotational speed of the optical disc.

By the way, recording errors occur when the recording pulse width or optical intensity of the light beam is not appropriate for the optical disc, but if the recording pulse width and optical intensity and the recording film sensitivity of the optical disc are properly managed, recording errors can occur. In this case, defects in the recording film of the optical disc become dominant. Defects in the recording film are called pinholes or black holes, and in either case, the light reflectance is significantly lower than that of a recording film without defects.

(Problems to be Solved by the Invention) In conventional optical disk devices, when a recording error occurs, after completing the information recording operation, a reproduction processing operation is performed to once reproduce the recorded information and eliminate the recording error. Therefore, there is a problem in that recording error processing takes a long time and requires a long recording time.

In view of such problems, it is an object of the present invention to provide an optical disc device that can shorten the time for processing information recording errors and can record information at high speed.

[Means to solve the problem]

An optical disc device according to the present invention is an optical disc device in which a photodetector receives reflected light of a light beam projected onto an optical disc by a light emitting element, and records and reproduces information on the optical disc based on the output of the photodetector. an oscillator that outputs a signal, a counter that counts the clock signal during a period in which a recording signal that modulates the light beam of the light emitting element and a detection signal of the photodetector do not correspond, and a count value of the counter and a predetermined value. The present invention is characterized in that the comparator is configured to output a recording error signal when the count value exceeds a predetermined value.

[Effect]

The photodetector receives the reflected light of the light beam projected onto the optical disc. The oscillator outputs a clock signal. The counter counts clock signals during a period in which the recording signal modulating the light beam of the light emitting element and the detection signal of the photodetector do not correspond. The comparator compares the count value of the counter with a predetermined value, and outputs an output when the count value exceeds the predetermined value.

Thereby, the presence or absence of a recording error is determined within the time required to complete the recording operation.

〔Example〕

The present invention will be described in detail below with reference to drawings showing embodiments thereof.

FIG. 1 is a block diagram of essential parts of an optical disc device according to the present invention. An optical head 4 having a built-in optical sensor 5 is arranged on one side of an optical disc 1, which is an information recording medium, at a distance from the optical disc 1. A light beam 3 emitted by an optical head 4 is projected onto one side of the optical disc 1. The output of the optical sensor 5 is input to a waveform shaping circuit 6, and the output thereof is input to one input terminal of an XOR circuit 12. The waveform shaping circuit 6 is provided with a differentiating circuit (not shown). The output of the XOR circuit 12 is the D flipflop 13.
The output of the D flip-flop 13 is input to the clock input terminal CK of the counter 14. A counter output, which is the count value of the counter 14, is input to a comparator 15, and its output is input to the CPU 16.

The CPU 16 controls the period rH during which the light beam moves through l sectors.
A counter control signal that becomes the J level is manually input to the clear terminal CL of the counter 14. The recording error detection signal output by the CP016 is input to, for example, a recording signal output control section (not shown) that re-outputs the recording signal and a servo control section of the optical head. The output of the register 11, in which the set value to be determined as a recording error is set in advance, is input to the comparator 15.

A clock signal, which is the oscillation output of the oscillator 10 using a crystal, is input to the clock input terminal 13 of the D flip-flop 13 and the recording signal generation circuit 9. The recording signal output from the recording signal generation circuit 9 is input to the light emitting element drive circuit 8 and the delay line 7, and the output of the delay line 7 is input to the other input terminal of the XOR circuit 12.

The output of the light emitting element drive circuit 8 is provided to the optical head 4,
It is applied to a light emitting element (not shown) that emits a light beam.

Next, the operation of the optical disc device constructed in this way will be explained with reference to FIG. 2. FIG. 2 is a timing chart of signals of various parts of the optical disc device.

When recording information on the optical disc 1, a clock {ε number Sl shown in FIG. The recording signal generating circuit 9 manually inputs a recording signal S2 shown in FIG. 2(b) to the light emitting element driving circuit 8, for example. Then, the light beam 3 emitted by the optical head 4 is modulated by the recording signal S2, and information is recorded on the optical disc 1.

A detection signal S3 of the optical sensor 5 is obtained as shown in FIG. 2(c) by the reflected light of the light beam projected onto the optical disc l. In this FIG. 2 (c), the range indicated by a is the period when there is a defect in the recording film of the optical disc 1 and the light beam is projected to that position, and even though the light beam 3 is being projected. This indicates that the optical sensor 5 is not detecting the reflected light.

The detection signal S3 of the optical sensor 5 is differentiated within the waveform shaping circuit 6, and the differentiated signal S4 becomes as shown in FIG. 2 (2).

Then, at the time when the differential signal S4 falls, that is, when its level reaches the threshold value, the waveform shaping circuit 6
A rising pulse signal S5 is output as shown in FIG. By the way, the pulse signal S5 becomes a pulse signal similar to the recording signal S2 when there is no defect in the recording film, but during the period a when the light beam is projected onto a position where there is a defect in the recording film, the waveform shaping circuit 6 Pulse signal S as shown in figure (E)
5 will not be output. On the other hand, the recording signal generation circuit 9
The recording signal S2 outputted by the waveform shaping circuit 6 is delayed by a predetermined time by the delay line 7, and is outputted from the delay line 7 as a pulse signal S6 synchronized with the pulse signal S5 outputted by the waveform shaping circuit 6. These pulse signals S5 and S
6 is input to the XOR circuit 12, and when its logic is established, its output signal is input to the human input terminal D of the D flip-flop 13. When the detection signal S3 of the optical sensor 5 is obtained according to the recording signal S2,
That is, when both pulse signals S5 and S6 are obtained, there is no output from the XOR circuit 12, no input signal to the D flip-flop 13, and the D flip-flop 13 does not output a clock signal. However, if there is a defect in the recording film of the optical disc and the pulse signal SS disappears while the pulse signal S6 is present as shown in FIGS. When the logic is established, its output is applied to the input terminal D of the D flip-flop 13. Then, the D flipflop 13 outputs the clock signal of the clock a to which the signal is applied from the XOR circuit 12, and provides it to the counter 14. CPIJ
16 controls the counting operation of the counter 14,
A counter control signal at rHJ level is applied to the counter 14 during a period for recording information in one sector, and the counter 14 is operated to count during that period. Then, the counter output of the counter l4 is input to the comparator 15. The comparator 15 compares the count value of the counter output with a setting value preset in the register 1l to determine a recording error, and outputs an output when the count value exceeds the set value and outputs an output to the CPU 16.
Enter. Thereby, the CPU 16 detects that a recording error has occurred, and uses the error detection signal to re-output the recorded information of the recording error, re-record the information in other required sectors and required addresses, and performs recording error processing control. will be carried out.

FIG. 3 is a block diagram of the main parts of an optical disc device showing another embodiment of the present invention. The output of the optical sensor 5 is applied to the positive input terminal 10 of the comparator 23, and the negative voltage -■ is applied to the negative input terminal 1.

The output of the comparator 23 is given to one input terminal of an AND circuit 24. A counter control signal from the CPU 16 is applied to the other input terminal of the AND circuit 24, and its output is applied to the clear terminal C of the counter 14.

A clock signal output from the oscillator 10 is applied to the recording signal generating circuit 9 and the clock input terminal CK of the counter 14. The other structure is the same as that shown in FIG. 1 except that the waveform shaping circuit 6, delay line 7, XOR circuit 12, and D frisop flop l3 are removed.

Next, the operation of this optical disk device will be explained with reference to FIG. FIG. 4 is a timing chart of external signals of the optical disc device.

When recording information on the optical disc 1, a clock signal S1 shown in FIG. The recording signal generation circuit 9 inputs, for example, a recording signal S2 shown in FIG. 2 to the light emitting element driving circuit 8. Then, the light beam 3 emitted by the optical head 4 is modulated by the recording signal S2, and information is recorded on the optical disc 1. A detection signal S3 of the optical sensor 5 is obtained as shown in FIG. 2(c) by the reflected light of the light beam projected onto the optical disc l. The range indicated by a in FIG. 4(C) is the period when there is a defect in the recording film of the optical disc 1 and the light beam 3 is projected onto that position, and even though the light beam is being projected. Regardless, the optical sensor 5 indicates that the reflected light is not detected.

The detection signal S3 of the optical sensor 5 is applied to the positive input terminal 10 of the comparator 23, which is applying a negative voltage -2 to the negative human power terminal -. Then, the comparator 23 outputs the detection signal S
When the level of 3 exceeds the threshold value V' set in the comparator 23, it becomes the rLJ level (Fig. 2 (2))
A pulse signal S7 shown in is outputted and applied to the AND circuit 24. For example, the AND circuit 24 is supplied with a counter control signal S8 shown in FIG.
When the logic between the pulse signal S7 and the counter control signal S8 is established, the output of the AND circuit 24 is applied to the clear terminal CL of the counter 14. This counter 14 is an AND circuit 2
When the output of AND circuit 24 reaches rHJ level, the clock signal S1 output from oscillator 10 starts counting.

By the way, the recording signal S1 generally employs a modulation code in which the number of consecutive rHJ or rLJ is limited, and a value larger than the maximum value of the consecutive number (for example, a setting value of 8) is used.
is preset in the register 11 in order to determine that there is a recording error, and the set value and the count value from the counter 14 are respectively given to the comparator 15, and the comparator 15 compares them. If the count value becomes larger than the set value of the register 1l, it is assumed that a recording error has occurred when 8 clocks have been counted [see Figure 4 (e) and (e)], and an output is issued to the CPIJ. 16.

Thereby, the CPU 16 detects that a recording error has occurred, and transmits the signal to a recording signal output control section (not shown) that re-outputs the recording signal, and to a required sector different from the sector in which the recording error has occurred, and a required sector. Recording error processing control is performed by giving the address to the accessing servo control unit and rerecording the information.

When information is recorded on the optical disc l in this way, it is possible to determine whether a recording error has occurred immediately after recording one sector. Therefore, it is not necessary to wait for the completion of the information recording operation and then perform the reproduction operation to reproduce the recorded information to determine whether there is a recording error, as in the conventional case. Thereby, the time required for processing recording errors can be shortened.

Note that in this embodiment, information recording errors were determined by clearing the counter in units of one sector, but this is just an example, and the period for determining recording errors may be selected as appropriate, and is limited to this embodiment. It's not something you do.

〔Effect of the invention〕

As detailed above, the present invention makes it possible to determine the presence or absence of a recording error immediately after recording in recording units obtained by dividing one track, so that the recorded information can be reproduced after waiting for the completion of the information recording operation. There is no need to perform playback operations. Thereby, the recording error processing time can be significantly shortened. Therefore, according to the present invention, when a recording error occurs, the time required to process the error is not prolonged, and therefore, an excellent effect can be achieved in that an optical disc device with a high recording speed can be provided.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the main parts of an optical disc device according to the present invention, Fig. 2 is a timing chart of signals of each part thereof, and Fig. 3 is a process diagram of the main parts of an optical disc device showing another embodiment of the invention. , FIG. 4 is a timing chart of the signals of each part. 1... Optical disk 4... Optical head 5... Optical sensor 6... Waveform shaping circuit 10... Oscillator l2... XOR circuit 15... Comparator 24... AND circuit 9...・Recording signal generation circuit 14...Counter patent Applicant: SANYO Electric Co., Ltd.

Claims (1)

[Scope of Claims] 1. In an optical disc device in which a photodetector receives the reflected light of a light beam projected onto an optical disc by a light emitting element, and records and reproduces information on the optical disc using the output of the photodetector, a clock signal is provided. an oscillator that outputs an oscillator, a counter that counts the clock signal during a period in which a recording signal that modulates the light beam of the light emitting element and a detection signal of the photodetector do not correspond, and a count value of the counter and a predetermined value. What is claimed is: 1. An optical disc device comprising: a comparator for comparing the count values, and the comparator is configured to output a recording error signal when the count value exceeds a predetermined value.