JPS6224436A - Optical information device - Google Patents

Abstract

PURPOSE:To securely identify a defective area by recording a deleted data mark signal having a certain pattern at an inversion interval larger than Tmax in a recording defective area and controlling a deleted data mark detecting means in accordance with an average reflected light beam at recording. CONSTITUTION:Read checking is executed by a read circuit 16. When a recording defect is detected, a microcomputer 19 switches the modulated and recorded waveform of a semiconductor laser 1 into the deleted data mark signal in the recording defective area to write again. Afterwards, when a data reading request in the defective area is issued, a comparator circuit 21 compares the reproduction signal of a photodetector 15 with a comparison voltage (c) set by a D/A converter 20 to output a signal (d). A deleted data mark detecting circuit 22 detects the defective area and outputs it to the microcomputer 19, which discriminates the defective area, invalidates read data and accesses an alternative area.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical information device related to optical information processing.

A magnetic disk device is typical as an auxiliary storage device in a conventional technical computer system. In the case of a magnetic disk device, when a recording defect is detected in a read check immediately after writing, information is rewritten to a replacement area associated with the defective area. At this time, in the defective area,
After erasing once, write a pleated data mark signal (for example, in the IBM format MFM recording method, 11 data including the missing clock),
After invalidating the data, if there is a request to read data from this defective area after that, the replacement area is accessed.

Incidentally, in recent years, the development of optical information devices that apply laser light as large-capacity information storage devices has been progressing. Typical examples are the drilling type and the phase change type, which utilizes changes in reflectance due to amorphous or crystalline phase changes caused by heat.Since they are irreversible and cannot be erased, a read check immediately after writing may cause a recording failure. When detected, a deleted data mark signal (for example, 1") similar to data similar to that on a magnetic disk is written and the data cannot be invalidated as a defective area, which is a problem. Therefore, a recording format for an optical disc has been proposed as shown in FIG. 4A.The optical disc has a plurality of data recording sectors N and N+1 for recording data. is an index part in which an ID synchronization byte 23, a physical track address 24 on the right, and a sector address 25 incremented by one are pregrouped, a data synchronization byte 27, a track address/sector address 28, fixed length data 29, and an error correction code. (ECC) byte 3° data part, and also has a bad sector flag 26 indicating that the sector is bad, so that when a recording defect is detected in the read check, the bad sector flag area 26 is deleted. A defective area was identified by writing a deleted data mark signal. However, when this method is used, if there is a defect in the area of the bad sector flag 26, the deleted data mark signal is correctly written. A mark signal cannot be written, making it impossible to identify a defective area.

Furthermore, by adding the area T of the bad sector flag 26 as in the recording format shown in FIG. 4A, there is a problem that the storage capacity is reduced compared to the recording format shown in FIG. 4B.
For example, Japanese Patent Application Laid-Open No. 59-94243).

Problems to be Solved by the Invention Although such conventional methods have the advantage of large capacity, when a recording defect is detected in a read check immediately after writing, it is difficult to identify the defective area during reading. Therefore, reliability as an auxiliary storage device in a computer system cannot be satisfied.

The present invention has been made in view of these points, and an object of the present invention is to provide a reliable optical information device as an auxiliary storage device in a computer system.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides that, when a recording defect is detected in a read check immediately after a write-in, the defective area has a maximum reversal interval T! in the data recording modulation method. I
A fixed pattern of de-IJ-ted data mark signals with a larger inversion interval than IILX (for example, 2T of MFM modulation method) is recorded, and if there is a request to read this defective area afterwards, the average of the information track is recorded in advance. Depending on the average reflected light obtained by means of detecting reflected light,
The defective area can be easily identified by the deleted data mark signal detection means in which the comparison level of the detection means for detecting the deleted data mark signal is set.

Effect The present invention has the above-described configuration, so that the recording failure area has Tm.
a! The deleted data mark signal is recorded in a constant pattern with a larger reversal interval, and when read, the deleted data mark is detected according to the average reflected light obtained by means of detecting the average reflected light of the information track in advance. Since the detection control means is controlled and the conventional recording format is not used, defective areas can be easily identified without reducing the recording capacity. Reliability can be satisfied.

Embodiment FIG. 1 is a block diagram showing an embodiment of the optical information device of the present invention. In FIG. 1, a laser light source 1 is made of a semiconductor laser and emits laser light. A collimator lens 2 converts the laser beam from the laser light source 1 into parallel light. 3 polarizing beam splitters, 4 is our wave plate. Reference numeral 6 indicates an objective lens, and 6° indicates an optical pickup that operates the objective lens 5 in the focusing and tracking directions, and is constituted by known driving means such as a voice coil motor. Reference numeral 7 denotes an optical disk, and 8 a ba/'%-fu mirror divides the reflected light from the optical disk γ. 9 is a condensing lens,
It is a 10-digit split mirror. Reference numeral 11 denotes a focus control photodetector, which is composed of two divided photodetectors, and obtains a focus error signal from the differential output of each photodetector, and obtains a focus sum signal from the sum output of the photodetectors. . 12 is a focus control circuit that controls the loop gain of the focus system using the focus sum signal 11, and operates the optical pickup 6 in the focusing direction based on the focus error signal. 13
is a tracking control photodetector which has the same configuration as the focus control photodetector 11 and obtains a tracking error signal and a tracking sum signal. A 14-track tracking control circuit has the same configuration as 12, and controls the loop gain of the tracking system using the tracking sum signal of 13, and
The optical pickup 6 is operated in the traverse and y-king directions based on the king error signal. 16 is a photodetector that receives reflected light from the optical disk 7; Reference numeral 16 denotes a reading circuit that reads data from the information track and detects recording defects by checking for errors from the read data.

17 is a low-pass filter circuit (hereinafter referred to as P, F), which extracts the low frequency component of the output from the photodetector 16. 18 is an A/D converter which converts the analog signals of the photodetection outputs of L, P, and F17 into digital signals. A microcomputer (hereinafter referred to as microcomputer) 19 controls the apparatus. 19 microcontrollers, 18 A/Ds
The converter obtains the average reflectance of the optical disc, performs calculations, and sets data corresponding to the average reflectance. 20
is a D/A converter, which converts the digital signal corresponding to the average reflectance output from the microcomputer 19 into an analog signal. 21 is a comparator circuit, and 21 (7) converts the output of the D/A converter into a detection voltage. 22 is a deleted data mark detection circuit, and when it detects a deleted data mark signal of constant/N11 turns, it detects a recording defect. It outputs to the microcomputer 19 that it is the area.The arrow drawn in the optical system section in the figure indicates the laser beam path.

The optical system of the optical information device configured as described above will be explained. A laser beam emitted from a laser light source 1 passes through a collimator lens 2 to become parallel light, and is focused onto an information track formed on an optical disk 7 by an objective lens 6 via a polarizing beam splitter 3 and a λ/4 wavelength plate. At this time, the information track of the optical disk γ is rotating with surface runout and eccentricity, so in order to focus the laser beam on a predetermined information track, driving is performed based on the focus error signal and the tracking error signal. A voltage is applied to the optical pickup 6 to operate the objective lens 5 in the focusing and tracking directions, thereby causing the laser beam to follow a predetermined track.

Recording on the optical disc 7 is performed by modulating the intensity of the laser light source 1 while following a predetermined track. In addition, the reflected light from the optical disk 7 follows the incident optical path and the reverse optical path, passes through the λ/4 wavelength plate 4 twice, and becomes light that is 9σ polarized with the incident light, going straight through the polarizing beam splitter 3. , is split into two directions by a half mirror 8, and one enters a condenser lens 9 and the other enters a photodetector 16. The reflected light exiting the condensing lens 9 is split by a splitting mirror 1°, and one side is sent to a focus control photodetector 1.
1 and the other is a tracking control photodetector 13
The light is focused on. A focus error signal and a tracking error signal are generated by obtaining a differential output from the focus control photodetector 11 and the tracking control photodetector 13, and a focus sum signal and a tracking error signal are generated from the sum signal of each photodetector. Create a tracking sum signal. Focus control a is performed in a focus control circuit 12 that drives the aforementioned optical pickup 6 in the focus direction and feeds back the focus error signal. Further, in the focus control circuit 12, the loop gain of the feedback control of the focus system described above is controlled based on the focus sum signal. Similarly, the tracking control circuit 14 obtains a tracking error signal from the tracking differential output, drives the optical pickup 6 in the tracking direction and feeds it back, and also controls the feedback loop gain using the tracking sum signal to perform tracking control. , following the desired information track. On the other hand, the photodetector 16 is composed of one photodetector,
An output proportional to the amount of light reflected from the information track on the disc can be obtained.

Here, the signal waveforms of each part in FIG. 2 will be explained. The optical system described above modulates the semiconductor laser 1 and records data on the target information track, and the signal is sent to the photodetector 15.
The read signal a is obtained by the reading circuit 16, and the reading circuit 16 performs a read check and instructs the microcomputer 19 as to whether or not there is a recording defect.If no recording defect occurs, the microcomputer 19
The data from the program/D converter 18 is taken in. That is, by passing the reproduced signal a, P, and F 17 of the photodetector 15, high frequency components are removed, and the voltage of the average amount of reflected light of the tracks without recording defects on the optical disc 7 is obtained. The microcomputer 19 calculates the voltage of the average amount of reflected light, and calculates D
The output C of the A/A converter 2o outputs a digital signal having a voltage of about -1 to the 20 D/A converters. D/A converter 2
o converts the digital signal from the microcomputer 19 into an analog signal, and is set as the detection voltage C of the comparator circuit 21. The comparator circuit 21 compares the reproduced signal a of the photodetector with C set by the D/A converter 20, and outputs a signal d to the deleted data mark detection circuit 22. The deleted data mark detection circuit 22 detects a fixed pattern with an inversion interval larger than the maximum inversion interval T□ of recorded data (for example, when all data areas are
When a deleted data mark signal is detected in the section (high interval), the microcomputer 19
Output to.

Here, recording defect detection will be explained based on the waveforms shown in FIG. The playback signal when data is recorded on the target information track! When L1 performs a read check with the reading circuit 16 due to dust, defects, etc. on the optical disc 7 and detects a recording defect, the microcomputer 19 sets the modulated recording waveform of the semiconductor laser 1 in the recording defect area as a deleted data mark. Switch to signal and write again. After that, when there is a request to read data regarding this defective area, the comparator circuit 21 compares the reproduced signal a2 of the photodetector 15 and the ratio 1 bite voltage C already set in the D/A converter 2o, and the signal d1 is output, the deleted data mark detection circuit 22 detects the defective area, and the microcomputer 1
9 is output. The microcomputer 19 identifies the defective area, invalidates the read data, and accesses an alternative area.

In addition, in the above, settings were made for areas with no recording defects in the read check after recording, but if there is a recording defect in the read check after recording, the average reflection of the deleted data mark signal The detection level may be set by light. In that case, the D/A converter 20
In the output data setting, if the first area is a defective area, a defective area deleted data mark signal is recorded, and the average reflected light amount b' (not shown) for this defective area is recorded.
is taken in by the MU/D converter 18, and the microcomputer 19 performs calculations, and the output voltage C of the D/A converter 20 is set to be approximately -b', thereby identifying a similar defective area. I can do it.

As described above, according to this embodiment, the output of the photodetector 16 is passed through the L-P and Fl 7 and detected by the MU/D converter 18 and the microcomputer 19, and the comparator 21 corresponding to the detection signal is
By calculating the detection level and converting it with the D/A converter 2o, it is possible to set the deleted data mark signal indicating the recording defective area to a detection level that can identify it, making it easy to identify the defective area. Detection is possible.

In the above embodiment, the photodetector 16 is provided separately, but it may also be used as the focus control photodetector 11' or the tracking control photodetector 13. In this case, the sum signal of two photodetectors, the focus control photodetector 11 and the tracking control photodetector 13, is used instead.

Effects of the Invention As described above, according to the present invention, a deleted data mark signal of a constant pattern with a reversal interval larger than Tax is recorded in a recording defect area, and when reading, an information track is recorded in advance. The defective area can be reliably identified without reducing the recording capacity by the detection control means in which the deleted data mark detection means is controlled in accordance with the average reflected light obtained by the means for detecting the average reflected light of the It is possible to obtain a reliable optical information device as an auxiliary storage device in a computer system.

[Brief explanation of the drawing]

FIG. 4 is a format diagram of the recording format. 16...Photodetector, 16...Reader, 17...-Low pass filter circuit, 18...
...Mu/D converter, 20...D/Person converter,
21... Comparator circuit, 22...
Deleted data mark detection circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure υ Figure 3

Claims (3)

[Claims] (1) A laser beam is irradiated through an optical system to an information track formed on an optical disk, and the reflected light from this information track is received by a photodetector to maximize the reversal of recorded data indicating a defect in the information track. The apparatus is configured to record a deleted data mark signal in a constant pattern with an inversion interval larger than the interval T_m_a_x, and includes means for detecting an average reflected light from the information track, and a means for detecting an average reflected light from the information track, and a means for detecting the average reflected light from the information track, An optical information device comprising detection control means for controlling means for detecting a deleted data mark signal indicating a defect. (2) The optical information device according to claim 1, wherein the means for detecting the average reflected light is constituted by a low-pass filter circuit for extracting low frequency components from the photodetector. (3) Claim 1 or 2, wherein the photodetector doubles as at least one of a focus control photodetector and a tracking control photodetector for controlling a laser beam onto an information track on an optical disk. The optical information device according to item 2.