JPH05189876A - Optical information recorder/reproducer and recording medium - Google Patents

Abstract

PURPOSE:To provide a data read out system in which data is recorded/ reproduced positively through an information recorder/reproducer and compatibility of initial recording medium and drive compatibility of data for defective or repeatedly used recording medium are guaranteed. CONSTITUTION:A reproduced signal processing circuit is constituted such that a data error detecting means, i.e., a microprocessor 17, can set one or a plurality of variable parameters of envelope detection circuits A10 and the like using the output of a D/A converter. Reliability of read out data can be enhanced through a constitution wherein data is read out again by additionally providing a conventional system with a step for resetting the parameters prior to reread- out upon detection of a data error.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing apparatus for recording / reproducing information on / from an optical disc having an optically detectable guide track, and more particularly to a data error recovery process during reproduction of a recording signal. is there.

[0002]

2. Description of the Related Art An optical disc, which is considered to be a promising high-density and large-capacity memory, requires an error control technique in order to overcome a bad error rate as compared with a magnetic recording device for optical recording. An optical disc is generally provided with an optically detectable track such as a guide groove in order to increase the track density, and the recording layer formed on this guide track has a laser beam focused to a diameter of about 1 μm. Then, an information signal is recorded by piercing, deforming the shape of the groove, changing the optical reflectance of the recording layer, magneto-optical recording or the like.

Since the recording pits and track pitches are on the order of microns, various defects, dust, and scratches are generated depending on the manufacturing process of the optical disc or the environment in which the disc is used, resulting in reproduction signal dropout. As a result, the raw error rate of the optical disk is said to be 10 ⁻⁴ to 10 ^−6, and 10 times that of the typical typical conventional recording medium, the magnetic disk.
Currently, it is much worse than the error rate of ^-9 to 10 ^-12 .

For this reason, an optical information recording / reproducing apparatus using an optical disk has a strong error control and reproduces a track recorded at the time of recording to confirm whether data is correctly recorded (hereinafter referred to as a verify function or simply It is called Verify). A confirmation operation is performed at the time of data recording by using this verify function, and for a sector which is recorded in the defective sector as described above and the content of the data cannot be guaranteed, an information signal is recorded in a substitute sector provided in another position in advance. A replacement work is carried out.

Further, not only in the optical information recording / reproducing apparatus but also in the information recording / reproducing apparatus, when an error is detected at the time of reading the data, it is general to try the re-reading of the target information as the error recovery processing.

An example of recovery processing in the above-described conventional information recording / reproducing apparatus when an error is detected during data reading will be described below with reference to the drawings.

FIG. 5 is a block diagram of a signal reproduction processing circuit in a conventional information recording / reproducing apparatus.

In FIG. 1, 1 is an optical disk, 2 is a motor for rotating the disk, and 3 is an optical block for irradiating the optical disk 1 with a laser beam emitted from a semiconductor laser or the like to a light beam of about 1 μm. Reference numeral 4 denotes a laser drive circuit that modulates and drives a semiconductor laser or the like according to a recording information signal input from the terminal A. 42 is a preamplifier that amplifies a weak signal from the optical disc. Reference numeral 43 is a frequency characteristic correction circuit for emphasizing a specific frequency to make the data easier to read. 7 is a differentiating circuit, 8 is an amplifier, 9 is a zero-cross comparator, 15 is an AND gate, 46 is a PLL circuit, 16
Is an address and data reading circuit, and 63 is a microprocessor for controlling recording / reproducing signals and the entire device. Reference numeral 44 is an envelope detection circuit A for detecting the envelope of the signal, 11 is a comparator, 12 is an envelope detection circuit B, 14 is a comparator B, and 45 is a bias setting circuit for setting the bias of the comparator B.

The operation of the reproduction signal processing circuit for the optical disc configured as described above will be briefly described. The reproduction signal read by the optical block 3 is supplied to the preamplifier 42.
Is amplified by. The reproduction signal amplified by the preamplifier 42 has its frequency characteristic corrected by the frequency characteristic correction circuit 43. FIG. 7- (49) shows an example of the output signal of the frequency correction circuit.
Shown in. The peak detection of the reproduction signal is performed by the circuits of two systems. One is a signal peak detection system, which comprises a differentiating circuit 7, an amplifier 8, and a zero-cross comparator 9. The output signal of the differentiating circuit is as shown in Fig. 7- (50), and the output signal of the zero-cross comparator 9 is shown in Fig. 7- (5).
As in 1), the information of the data is put on the falling edge. The cross portion due to the slanted line is a noise signal.

The other is a data gate detection system for removing the noise signal, which is an envelope detection circuit A4.
4 and a comparator A11. The output signal of the envelope detection circuit A44 is normally as shown in FIG.
As shown in (a), it is set to clip about 40% of the input signal amplitude. Therefore, the output signal of the comparator A11 becomes as shown in FIG. 7- (52), and the peak of the data is detected by AND of (51) and (52) in FIG. 6- (53).

Further, data output is performed by a gate signal by the data presence / absence detection circuit, and is output only to the sector where data is recognized to be recorded. The data presence / absence detection circuit is performed by the envelope detection circuit B12, the bias setting circuit 45 and the comparator B14. The output of the comparator B14 is as shown in FIG.
The output of the AND gate 15 is shown in FIG. 7- (55). This binary signal is read by the address and data reading circuit 16 and error information is returned to the microprocessor 63 when an error is detected during or after reading the data.

FIG. 6 shows a flow chart of a process of reading data in the conventional information recording / reproducing apparatus.

If the data can be read normally at one time, 19
(Data read command acceptance) -47 (Retry counter initialization) -22 (Data read execution) -23 (Determination of error detected) -24 (Command end) processing is performed. 1 if the data can be read in several rereads
9-47-22-23-48 (Increment of retry counter) -26 (Judgment whether limit of retry number is exceeded) -22-23-48-26 -...- 48-26-
22-23-24.

[0014]

However, in the conventional technique, the remaining portion of the previously recorded signal as shown in FIG. 8- (56) (hereinafter referred to as the unerased remaining signal; the broken line portion in FIG. 8) is used. Next, when the data is superposed on a new signal that has been updated in the same sector, even if the data can be normally read by verifying a certain optical disk drive, it will be different due to manufacturing variations of the drive (optical system and beam variations of semiconductor laser etc.) However, an error may occur no matter how many times the data is read again. A brief description will be given below.

FIG. 8- (56) shows the output signal of the frequency characteristic correction circuit 43 shown in FIG. Fig. 8- (56)-(a)
Is an output signal of the envelope detection circuit A44 shown in FIG. 5, and a gate signal for peak detection is shown at (59).
(57) is the output signal of the differentiating circuit 7. (58) is an output signal of the zero-cross comparator 9. Therefore, the peak of the data is detected by AND in (58) and (59) in the figure, and a part of the unerased signal is erroneously detected as shown in (60) in the figure. The data presence / absence detection gate signal is as shown in (61), and the output signal of the AND gate 15 is also erased as in (62), and a part of the remaining signal is left and a data error occurs.

If a data error occurs as described above, no matter how many times the data is read again, the flowchart in FIG.
After the process of -47, the process of 22-23-48-26 is repeated N times (where N is the specified number of times of re-reading), and then 2
The process 7 is performed.

As described above, in one optical disk drive, for example, a sector having a large number of unerased signals that can be normally read by verification may cause a data error in another drive.

In view of the above problems, the present invention changes the setting of a plurality of parameters that can be set in the reproduction signal processing circuit when data error is detected during or after reading data from a recording medium, and re-reads the data. (EN) An optical information recording / reproducing device intended to improve the reliability of recorded data by performing reading a plurality of times.

[0019]

In order to achieve this object, an optical information recording / reproducing apparatus of the present invention has one or a plurality of parameters that can be changed in a reproduction signal processing circuit, and is a micro-data detecting means for detecting a data error. The processor has a configuration in which the output of an analog switch or D / A converter can be used to set its parameters. In addition, in the process at the time of reading data, when a data error is detected, a process of resetting parameters before performing rereading is newly added to the conventional method to reread data.

Further, by recording the condition of each parameter, which is determined by the above-mentioned means, in which the error is most unlikely to occur, at a specific position of the disc, the condition for the subsequent reading can be immediately and accurately set.

[0021]

With the above structure, the reliability at the time of reproducing the write data is increased by setting the condition at the time of re-reading that the occurrence of an error due to the detection of the unerased signal of the specific component is minimized. Is possible.

[0022]

1 is a block diagram of an embodiment of the present invention. In FIG. 1, constituent blocks that are the same as those in FIG. 5 are assigned the same reference numerals and detailed description thereof is omitted. Reference numeral 5 is a preamplifier whose amplification factor can be changed by the setting of the microprocessor 17.
Reference numeral 6 is a frequency characteristic correction circuit in which the frequency correction characteristic can be changed by the setting of the microprocessor 17. Reference numeral 10 denotes an envelope detection circuit A ′ whose setting of the comparator level can be changed by the setting of the microprocessor 17. Reference numeral 13 is a bias setting circuit in which the setting of the voltage level can be changed by the setting of the microprocessor 17. Reference numeral 17 is a microprocessor capable of detecting an address and data read error from the address and data read circuit and setting a plurality of variable parameters of the reproduction signal processing circuit. Reference numeral 18 denotes a PLL circuit that extracts data in synchronization with the binarized data signal and that the extraction timing can be changed by setting the microprocessor 17.

The operation of the optical information recording / reproducing apparatus configured as described above will be described with reference to FIGS.

A description will be given of a case where the optical disc drive having the above-mentioned structure reads out data of a sector having a large number of unerased signals (shown by a broken line portion) as shown in FIG. 3 (28).

(28) is an output signal of the frequency characteristic correction circuit 6. First, in the first reading operation, the setting of the envelope detection circuit A'10 is set to about 4 for the input signal amplitude.
Since it is set at 0%, it becomes as shown in (28)-(a), and a part of the unerased signal is erroneously detected. The output signal of the comparator 11 is shown as (31). The output signal of the differentiating circuit 7 is as shown in (29), and the output signal of the zero-cross comparator 9 is also erased, so that the output of the AND gate 15 is also erased and a part of the remaining signal is detected. The output signal of the AND gate 15 is shown in (34). A data error occurs in the address and data reading circuit, and the microprocessor 17 detects the data error.

The microprocessor which has detected the data error prepares for the data re-reading operation according to the flow chart shown in FIG. The processing procedure is as follows: 19 (data read command acceptance) -20 (retry counter initialization, parameter control counter initialization)-
21 (reproduction signal processing circuit parameter setting) -22 (data reading execution) -23 (error detection presence / absence determination)-
25 (retry counter, parameter control counter increment) -26 (retry limit number determination) -21.

Next, in the second read operation, the microprocessor gradually advances the setting of the frequency characteristic correction circuit 6 by the parameter control counter in the flowchart shown in FIG. 2 to reduce the advance amount of the compensation circuit and suppress the high frequency component, for example. In addition, the envelope detection circuit A'10 is set at, for example, about 65% of the input signal amplitude.

The output signal of the frequency characteristic correction circuit in this case is as shown in FIG. Since the setting of the envelope detection circuit A'10 is set at about 65% of the amplitude of the input signal, it becomes as shown in (35)-(a), and the unerased signal is not detected. (38) shows the output signal of the comparator A11. Since the output signal of the differentiating circuit 7 is as shown in (36) and the unerased signal is detected, the output signal of the zero-cross comparator 9 is also as shown in (37) and the unerased signal is detected.

However, finally, the output signal of the AND gate 15 does not detect the unerased signal in order to remove the unerased signal from the comparator A11. Therefore, it is possible to read data without causing an error in the address and data reading circuit.

Here, the processing procedure is 22-23-24 (command end) in the flowchart of FIG.

In the case of data that cannot be read by two read operations, the above parameters are further changed and the data is read again, and if an error is detected in the read data even if the specified number of times of reading is reached, error processing is performed. I do.

In the above description, the setting of the frequency characteristic correction circuit 6 and the envelope detection circuit A'10 has been described, but as other parameters, the gain setting of the preamplifier 5 and the bias setting circuit which is the detection level of the presence or absence of data are set. There are timings for extracting data by shifting the level setting of 13 and the phase setting of the PLL circuit 18 used for data reproduction, but details thereof will be omitted here.

An example of changing the setting of each of the above conditions is shown below. The frequency correction circuit can be realized by preparing two or more sets of capacitors and resistors for advancement and switching them with an analog switch. The levels of the envelope detection circuit and the bias setting circuit can be directly changed by changing the data in the microprocessor by using the D / A converter. Alternatively, a plurality of biases may be prepared and switched using an analog switch. The amplification factor of the preamplifier can be changed by using a programmable amplifier, or by changing the feedback resistance of the amplifier with an analog switch. Further, the phase of the PLL can be changed easily by adding the output of the D / A converter with a constant gain after the phase comparator in the PLL. It goes without saying that these methods are examples and the above conditions can be changed by other methods.

Further, as shown in FIG. 9, before receiving a data read command, for example, immediately after the disc is inserted, the parameter setting to be set at the beginning of the reproduction signal processing circuit replaced with a predetermined code is made a variable parameter. When data is read out by determining by reading the track of the area, and when an error is detected in the data reading by this, the parameter is sequentially changed according to the setting of the parameter control counter, and the condition in which the error is minimized is shown in FIG. , The variable parameter area 1P
Even if the read conditions change due to unerased data, disc sensitivity dropout, or beam shape of the device, by performing the above read process based on this information when writing to the track and playing back next time. Since the central values of the parameters related to the disk can be immediately determined, highly reliable data reading conditions can be quickly determined. In FIG. 10, D11, D
Reference numeral 21 is address information, in which an address indicating a radial position of the track on the disk and sector information indicating an angular position are recorded in advance as uneven information such as intermittent information tracks. D12 is PCC data which is the data of the parameter control counter,
By reading this information, the optimum information at the time of the previous reproduction can be immediately set. The PCC data may be recorded in a fixed order for each parameter, or information defining a combination of each parameter with a specific code may be recorded. D13 is drive ID data, which may be individual identification information of the drive or group identification information representing a level such as model change. In this way, by recording the drive ID data and using it together with the PCC data as needed, the data read condition can be determined more accurately and quickly.

In this way, when the signal is read out, the setting is changed, the condition with the fewest errors is replaced with a predetermined code, and it is recorded at a specific position such as the control track on the disk or the head of the alternative area. When reproducing, the read process described above is performed based on this information, and even if the read conditions change due to unerased data, sensitivity dropout of the disc, beam shape of the device, etc., at least the parameters related to the disc Since the central value can be immediately determined, highly reliable data reading conditions can be quickly determined.

Although the above description has been made with respect to a disc with a large amount of unerased data, a data error occurring on a scratched disc or a disc used repeatedly can be corrected by setting different parameters. It has been confirmed that Therefore, by performing the parameter setting according to each signal deterioration factor, which is a feature of the present invention, at the time of re-reading, it is possible to dramatically improve the data reading reliability, which is a very effective means.

Although the embodiments have been described by using the optical disk, the invention relates to an apparatus for processing a recorded signal as will be apparent from the embodiments. Therefore, an optical card or an optical device for optically recording / reproducing a signal is used. A wide range of applications such as tape devices and magnetic recording devices are possible.

[0038]

As described above, according to the present invention, when a data error is detected during or after the reading of data from the recording medium, the setting of a plurality of parameters that can be set in the reproduction signal processing circuit is changed to re-create the data. The reliability of the recorded and reproduced data can be improved by performing the reading a plurality of times.

Further, by recording those conditions at a specific position on the disc and performing the above-mentioned reading process on the basis of this information when reproducing next time, the central values of the parameters relating to the disc are immediately obtained. Since it can be determined, it is possible to quickly determine a highly reliable data reading condition.

Further, in the embodiment, the data which can be read by re-reading is ended by the normal end routine. However, remembering that the re-reading has been done, the user is informed of the disc and the optical disc drive or the erasable disc. It is also possible to promote maintenance such as complete deletion.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a flowchart in an embodiment of the present invention.

FIG. 3 is an explanatory diagram of signals in one embodiment of the present invention.

FIG. 4 is an explanatory diagram of signals in one embodiment of the present invention.

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

FIG. 6 is a flowchart of a conventional example.

FIG. 7 is an explanatory diagram of signals in a conventional example.

FIG. 8 is an explanatory diagram of signals in a conventional example.

FIG. 9 is a flowchart in one embodiment of the present invention.

FIG. 10 is a diagram showing a recording form of a disc in an embodiment of the present invention.

[Explanation of symbols]

 5 Preamplifier 6 Frequency characteristic correction circuit 7 Differentiation circuit 9 Zero cross comparator 10 Envelope detection circuit A'11 Comparator A 13 Bias setting circuit 16 Address and data reading circuit 17 Microprocessor 18 PLL circuit

Claims (6)

[Claims] 1. A read signal processing circuit capable of changing the state setting of the circuit with one or a plurality of settable parameters when reading data from a recording medium,
An optical information recording / reproducing apparatus, wherein data is read by changing the setting of the reproduction signal processing circuit. 2. The binarization of the analog signal and the frequency characteristic of the frequency characteristic correction filter inserted in the processing circuit for the preamplifier's amplification factor and the binarized signal in the apparatus as the settable parameters. Of the comparator, the comparator level that is the bias of the envelope detection comparator that detects the presence or absence of the recording signal, and the PL for reading the information signal including the synchronization signal.
The optical information recording / reproducing apparatus according to claim 1, further comprising at least one of data extraction timings of the L circuit. 3. A method for detecting an error during or after reading data from a recording medium, wherein when a data error is detected by the detecting means, the setting of the reproduction signal processing circuit is changed to re-execute the data. 2. The optical information recording / reproducing apparatus according to claim 1, wherein reading is performed a plurality of times, and the reproduction signal processing circuit is set under the condition that the number of detected errors in the detection stage is minimized. 4. The optical information recording / reproducing according to claim 1, wherein each condition data having the smallest error detection number among the variable parameters is recorded at a specific location on a recording medium. apparatus. 5. An information recording medium, characterized in that, among the variable parameters, each condition data having the least error is recorded in a specific place on the recording medium. 6. The information recorded in a specific place on the recording medium is read out, and the parameters of the reproduction signal processing circuit are initialized based on the read out information. The optical information recording / reproducing apparatus described.