JPS60223035A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain an optical recording/reproducing device which can produce both an optical disk having an erasion function and an optical disk having no erasion function, by putting a specific mark to an optical disk which reproduces signals with the microspot light. CONSTITUTION:A recess/projection phase structure 17 is provided to a part of an arc of a mark area 16 of an optical disk 78 in order to attain the optical detection. The mark 17 for decision of polarity of reproduction signal is easily detected by a simple reflection type photodetector combining the light emitting and photodiodes in addition to the microspot light which performs record/reproduction in an information recording area 15. When the mark 17 is detected, the polarity of the preamplifier output signal is inverted. Thus the same polarity is obtained for input signals of a signal processing circuit regardless of the recording material. In case the difference of variation degrees is produced for reflection factor according to the recording material, the degree of amplification of the reproduction signal is controlled by the detected mark 17. Thus more stable reproduction signals can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical recording and reproducing apparatus that reproduces recorded signals by focusing a laser beam into a minute spot beam and applying a thermal change to an optical disk.

Conventional configuration and its problems In recent years, signals have been recorded and reproduced on optical disks by narrowing laser light down to about 1 μm.

In particular, devices have come into use that record by depositing a recording material on an original disk and applying a thermal change to it using a laser beam.

An example of the conventional optical recording/reproducing apparatus as described above will be described below with reference to the drawings.

FIG. 1 shows the configuration of a conventional optical recording/reproducing device. A laser beam from a semiconductor laser 1 is converted into a parallel beam by a condenser lens 2, and is incident on a diaphragm lens 6 by a total reflection mirror 4. The aperture lens 6 focuses this incident light onto the optical disk 8 into a minute spot of about φ1/1 m11. The reflected light from the optical disk 8 is again guided to the beam splitter 3 by the aperture lens 5 and the total reflection mirror 4, and is received by the photodetector 6. A disk motor 7 rotates the disk 8. A preamplifier 9 amplifies the photodetector output signal and inputs it to the demodulator 11 via the signal processing circuit 1o. Reference numeral 12 denotes a semiconductor laser drive circuit which drives the semiconductor laser 1 at a current value such that its optical output exceeds the sensitivity of the recording material in accordance with the signal from the modulator %13.

FIG. 2a shows a state in which signals are recorded on the guide track 14 in the form of grooves or grooves formed in advance with a phase structure on the optical disk 8. FIG. 2 shows the waveform of the output signal of the preamplifier 9 when the pits recorded in this manner are reproduced.

When the recording material on the original disk is irradiated with a minute spot of light, a thermal change occurs and the material turns black, as shown in FIG. 2a. In the blackened portion, the reflectance increases as shown in the output waveform of the reproduced signal in FIG. 2 (in the figure, the reflectance is large in the upward direction (positive direction)). In other words, the areas that are blackened and have a high reflectance are the areas where signals are recorded. Such a recording method is called blackening recording. [TeOx system] is used as a recording material corresponding to blackening recording.

Although recording is possible with TeOx-based materials, erasing (restoring) is difficult.

On the other hand, FIG. 3 is a diagram for explaining a recording material called white recording, and shows how bits are recorded along the guide track 14 similarly to FIG. 2. In FIG. 3 &, when the recording material on the disk is irradiated with a minute spot of light, a thermal change occurs and the material becomes white. In the whitened area where the signal is recorded, the reflectance decreases as shown in the reproduced signal output waveform in Figure 3 (Fig. 3 and Figure 2). rate is large). In other words, the area where the reflectance is reduced due to whitening is the area where the signal is recorded.

Such a recording method is called whitening recording, and TeGexOy is used as the material corresponding to this, and recording and erasing (restoration) are possible.

As explained above, the polarity of the reproduced signal output waveform obtained from the optical disc differs depending on the recording material. From the perspective of effective use of optical discs.

One recording/reproducing device does not necessarily use only an optical disk deposited with one type of recording material. The original disc, which uses a black recording method that cannot be erased, is suitable for recording information that must be preserved permanently and cannot be erased, and is expected to be used as a database. On the other hand, erasable whitening recording type optical discs are suitable for use as a work area for computer memory.

In this way, it is quite possible for one recording/reproducing device to record and reproduce information on an original disk using two or more types of recording materials. The problem in such a case is that the polarity of the reproduced signal differs depending on the recording material, as described above. The configuration of the optical recording/reproducing apparatus as shown in FIG. 1 has the disadvantage that recording and reproduction cannot be performed on an original disk using a recording material whose reproduction signal has a different polarity.

Purpose of the Invention In view of the above-mentioned drawbacks, the present invention provides an optical recording and reproducing device capable of stably reproducing even optical discs in which the polarity of the reproducing signal differs depending on the characteristics of the recording material. It is an object of the present invention to provide an optical recording/reproducing device capable of reproducing information from both disks.

Structure of the Invention The present invention provides a means for reproducing a recorded signal by focusing a light source such as a laser beam into a minute spot light and applying a thermal change to an optical disc, and a reproduction signal polarity determination mark provided on the optical disc or disc jacket. means for determining the polarity of the reproduced signal by detecting the polarity of the reproduced signal; means for controlling the polarity of the reproduced signal to normal rotation or inversion based on the determination result; and means for fully amplifying the reproduced signal based on the determination result. This is an optical recording/reproducing device that is equipped with means for controlling the amplification degree, and is an optical disc in which the polarity of the reproduced signal differs depending on the characteristics of the recording material, such as an original disc with an erasing function and an original disc without an erasing function. However, they can be stably recorded and reproduced using the same recording and reproducing device.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 4 shows the structure of a source disk of an optical recording/reproducing apparatus in an embodiment of the present invention.

In FIG. 4, 8 is an optical disk, and 15 is an information recording area in which recording is performed by concentrating a laser beam into a minute spot beam.

Guide tracks are formed in the information recording area 15 in a concentric or spiral shape.

Reference numeral 16 denotes an area for a reproduced signal separation determination mark provided at the inner peripheral portion of the information recording area. 17 is a reproduction signal polarity determination mark. The structure of this reproduced signal polarity determination mark portion is shown in FIG.

As shown in FIG. 5, by providing a part of the arc of the mark area 16 with a phase structure of concave and convex grooves similar to the guide track of the information recording area, optical detection becomes possible. This kind of phase structure is.

Like the guide track of the information recording area 16, it can be formed when the optical disk master is loaded. Therefore, the quality of the reproduced signal polarity determination mark is stabilized, and manufacturing costs can be reduced. The reproduced signal polarity determination mark 4 is.

Apart from the minute spot light used for recording and reproducing information in the information recording area, it can be easily detected using a simple reflective photodetector that combines a light emitting diode and a photodiode. When light from a light emitting diode or the like is irradiated onto the reproduced signal polarity determination mark portion having a groove structure, the light is diffracted and the reflectance decreases. This change in reflectance can be sufficiently detected with an inexpensive photodiode. The reproduced signal polarity determination mark is provided, for example, on the material for white recording as shown in FIG. 3, and is not provided on the material for black recording as shown in FIG. 2. If a mark is not detected, the polarity of the preamplifier output signal is left as is, and if a mark is detected, the polarity of the preamplifier output signal is inverted. By doing so, the polarity of the input signal to the signal processing circuit, such as the amount of waveform equalization, becomes the same regardless of the recording material of the disc. The formant of the reproduced signal polarity determination mark is not limited to the above-described determination of the presence or absence of a mark, and various other forms can be considered. It is also possible to encode the phase structure due to the unevenness of the groove by arranging it in the circumferential direction of the reproduced signal polarity determination mark area.

Also, depending on the recording material, not only the polarity of the playback signal.

The amount of change in reflectance between the recorded portion and the unrecorded portion may also be different. In such cases, by controlling the degree of amplification of the reproduced signal based on the detected polarity determination mark,
A more stable reproduction signal can be obtained.

FIG. 6 shows the configuration of an optical recording/reproducing apparatus according to an embodiment of the present invention. In FIG. 6, the components labeled with the same numbers as in FIG. 1 are the same as those in FIG. 1. In the figure, % 18 is a light emitting diode, % 19 is a photo diode, and these two constitute a reflection type photodetector to detect the presence or absence of the reproduced signal polarity determination mark 17 .

FIGS. 7a to 7d show signal waveforms at points a to d shown in the configuration diagram of FIG. 6. FIG. 7e shows the appearance of recording pits, and is an optical disk on which a whitening recording material with an erasing function is deposited, similar to FIG. 3.

In FIG. 6, a converter 20 compares the output signal of the photodiode 19 with the reference voltage VTI+, and converts the detected playback signal polarity determination mark into a pulse (FIG. 7b). When this pulse is input to the preset terminal of the flip-flop 21, a latched signal (FIG. 7C) is output from the enable output.

22 is an operational amplifier which inverts the reproduction signal output from the preamplifier 9 and outputs it. 2'3 a + 23 b+''j
:An analog gate switch is turned on when an L level is applied to the gate terminal. When the original disk 8 is attached to the disk motor 7, the disk motor 7.

A rotation command 24 is output. At the rising edge of this rotation command, 21 flip-flops are cleared.

If there is a polarity judgment mark like the one shown in Figure 6-17 indicating that the optical disc has an erasing function, the photodiode 1
9, a waveform as shown in FIG. 7a is detected. This detection signal is compared with the reference voltage of VTH by the comparator 2o and outputted and converted into a pulse (FIG. 7b).

The flip-flop output ζ is latched by the input pulse output, and the analog gate switch 232L is turned on. When the analog gate switch 23a is turned on, the operational amplifier 22
The preamplifier output is inverted. This situation is shown in FIG. 725. In this way, even in a disk using the whitening recording method having an erasing function, bits on which signals are recorded are outputted as voltages in the positive direction. Therefore, the signal processing circuit 10 similar to that of the blackening recording method. Stable reproduction is possible with the demodulator 11.

FIG. 8 shows the configuration of the signal processing circuit 10 in this embodiment. 26 is a gain control circuit, 27 is a waveform equalization amount, and 28 is a waveform shaping circuit.

Erasable optical disks and non-erasable optical disks differ not only in the polarity of the reproduced signal but also in the amplitude of the reproduced signal.

Therefore, in this embodiment, the gain control circuit 26 performs gain control of the reproduced signal amplitude using the determination signal of an erasable optical disc, that is, the output of the flip-flop 21. The output whose amplitude has been corrected by the gain control circuit 26 has its frequency characteristics corrected by the waveform equalizer 27 , and then is waveform-shaped by the waveform shaping circuit 28 and input to the digital demodulator 11 .

With this configuration, when reproducing an original disc made of a different recording material, the polarity of the reproduced signal can be reversed and the gain can be controlled at the same time.

A reproduced signal at the optimum level can be obtained.

In this embodiment, the reproduced signal polarity determination mark is provided on the inner circumference of the information recording area, but it may be provided on the outer circumference. Furthermore, it may be provided on the disc jacket instead of on the optical disc itself.

FIG. 9 shows an embodiment in which a reproduced signal polarity determination mark is provided on the disc jacket. 29 indicates the playback signal polarity determination mark, and a part of the disc jacket 3° is cut out.
Detected by a microswitch (not shown). In other words, the microswitch is turned off when the disc jacket is attached.
If the condition.

Indicates that the disc is erasable. When the signal from the microswitch is input to the preset terminal of the flip-flop 21, the output of the preamplifier e is inverted and applied to the signal processing circuit 1o, as described above.

Effects of the Invention As described above, the present invention provides a reproduction signal polarity determination mark that can determine the polarity of a reproduction signal on an optical disc or a disc jacket, detects this determination mark, and determines the polarity of the reproduction signal of the original disc. Based on the results, the polarity of the playback signal is inverted or forward controlled, and the gain of the playback signal is also controlled. Even optical discs in which the polarity of the reproduction signal and the amplitude of the reproduction signal are different can be stably recorded and reproduced by the same recording and reproduction apparatus.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the configuration of a conventional optical recording/reproducing device, Figure 2 is a diagram showing how signals are recorded on an optical disk using the blackening recording method and the reproduced signal waveform, and Figure 3 is a diagram showing whitening recording. FIG. 3 is a diagram showing how signals are recorded on the original disk of the system and the reproduced signal waveform. FIG. 4 is a plan view showing the structure of an optical disc of an optical recording/reproducing apparatus according to an embodiment of the present invention, FIG. 6 is a perspective view showing an example of the structure of a reproduced signal polarity determination mark, and FIG. FIG. 7 is a block diagram showing the configuration of an optical recording/reproducing apparatus in one embodiment. FIG. 7 is a diagram showing signal waveforms in each part of FIG. 6. FIG. 8 is a block diagram showing the configuration of a signal processing circuit. FIG. 7 is a perspective view showing another example of the structure of a reproduced signal polarity determination mark. 1... Semiconductor laser, 8... 4. Optical disk,
17゜29・・・Reproduction signal polarity determination mark, 18
... Light emitting diode, 19. Old photo diode, 22 ... Operational amplifier, 23a, 23b
・・Dan analog gate switch, 26・・Gain control circuit, 30・・・・Disc jacket. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 8 Figure 2 Figure 4 wrinkle diagram

Claims (1)

[Claims] A means for reproducing a recorded signal by focusing a first light source such as a laser beam into a minute spot light and applying a thermal change to an optical disc, and detecting a reproduced signal release determination mark provided on the optical disc or disc jacket. means for determining the polarity of the reproduced signal by determining the polarity of the reproduced signal; means for controlling the polarity of the reproduced signal to normal rotation or inversion based on the determination result; and means for controlling the degree of amplification for amplifying the reproduced signal based on the determination result. An optical recording/reproducing device comprising: