JPH0312375B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical recording/reproducing device that records/reproduces signals by concentrating a laser beam into a minute spot light 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 concentrating laser light to about 1 μm. In particular, devices have come into use that record by depositing a recording material onto an optical disk and subjecting it to thermal changes using laser light.

An example of a conventional optical recording/reproducing device 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 5 by a total reflection mirror 4. The aperture lens 5 focuses this incident light onto the optical disk 8 into a minute spot of about 1 μm in diameter. The reflected light from the optical disk 8 is again guided to the beam splitter 3 via the aperture lens 5 and the total reflection mirror 4, and is received by the photodetector 6. 7 is a disk motor and disk 8
is rotating. A preamplifier 9 amplifies the photodetector output signal and inputs it to a demodulator 11 via a signal processing circuit 10. Reference numeral 12 denotes a semiconductor laser drive circuit which drives the semiconductor laser 1 at a current value such that its output exceeds the sensitivity of the recording material in accordance with the signal from the modulator 13.

FIG. 2a shows a state in which a signal is recorded along a concave or groove-shaped guide track 14 formed in advance in a phase structure on the optical disk 8. FIG. 2b shows the waveform of the output signal of the preamplifier when the pits recorded in this manner are reproduced.

When a recording material on an optical disk is irradiated with minute spot light, a thermal change occurs and the material turns black as shown in FIG. 2a. The blackened portion has an increased reflectance, as shown by the reproduced signal in FIG. 2b. In other words, the part that is blackened and has a high reflectance is the part where the signal is recorded. This type of recording method is called blackening recording. TeOx-based materials are used as materials that correspond to blackening records. TeOx-based materials allow recording, but are difficult to erase.

On the other hand, FIG. 3 is a diagram explaining recording materials used in a recording method called whitening recording.
It shows pits being recorded along the guide track 14 in the same way as in FIG. In FIG. 3a, when the recording material on the disk is irradiated with minute spot light, a thermal change occurs and the material becomes white. The whitened portion has a reduced reflectance as shown in FIG. 3b. In other words, the portion where the reflectance is low is the portion where the signal is recorded. This kind of recording method is called whitening recording, and TeGexOy is used as a material corresponding to this, and recording and reproduction are possible.

As explained above, the polarity of the reproduced signal output waveform obtained from the optical disk when recording signals of the same polarity differs depending on the recording material. However, it is not always the case that only an optical disk using one type of recording material is used in one recording/reproducing device. The problem in such a case is that, as mentioned above, the polarity of the reproduced signal when recording signals of the same polarity differs depending on the recording material. The configuration of the optical recording and reproducing apparatus as shown in FIG. 1 has the disadvantage that recording and reproduction cannot be performed on an optical disk using recording materials in which the polarity of the reproduction signal is different.

Purpose of the Invention In view of the above-mentioned drawbacks, the present invention provides an optical recording and reproducing device that can stably record and reproduce even on optical discs in which the polarity of the reproduced signal differs when the same polarity signal is recorded depending on the recording material, and in particular, an optical disc with an erasing function and an optical disc with an erasing function. The purpose of the present invention is to provide an optical recording and reproducing device that can record and reproduce information on and from both non-functional optical disks.

Structure of the Invention The present invention provides a means for recording and reproducing signals by focusing a light source such as a laser beam into a minute spot light and applying a thermal change to an optical disk, and a recording device capable of determining the polarity of a recorded signal on the optical disk. This is an optical recording/reproducing device that is equipped with a signal polarity determination mark, detects the determination mark, and controls the polarity of the signal recorded on the optical disk to normal rotation or inversion based on the detection result. The same recording and reproducing device can be used for both erasable and non-erasable optical discs.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 4 shows the structure of an optical disk of an optical recording/reproducing apparatus in an embodiment of the present invention. In Fig. 4, 8 is an optical disk;
Reference numeral 15 denotes an information recording area in which recording and reproduction are performed by concentrating a laser beam into a minute spot beam. Information recording area 15
The guide tracks are formed concentrically or spirally. 16 is a recording signal polarity determination mark area provided inside the information recording area. 17 is a recording signal polarity determination mark, and the structure of this portion is shown in FIG. As shown in FIG. 5, optical detection becomes possible by providing a phase structure of concave and convex grooves similar to the guide track of the information recording area in a portion of the arc of the determination mark area 16. Similar to the guide track of the information recording area, such a phase structure can be formed during cutting of the optical disk master.

The recording signal polarity determination mark can be easily detected using a simple reflective photodetector that combines a light emitting diode and a photodiode, in addition to a light source such as a laser beam that performs recording and reproduction in the information recording area. When the recording signal polarity determination mark portion having the groove structure is irradiated with light from a light emitting diode or the like, the light is diffracted and the amount of reflected light is reduced. Changes in reflected light can be detected with an inexpensive photodiode.

For example, the recording signal polarity determination mark is provided on the white recording material as shown in Figure 3, and not on the black recording material as shown in Figure 2.If the mark is not detected, the modulator The polarity of the output signal remains unchanged, and if a mark is detected, the polarity of the modulator output signal is controlled to be inverted. By doing this, the polarity of the reproduced signal becomes the same regardless of the recording material of the optical disc.

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

FIGS. 7a to 7e show signal waveforms at points a to e shown in FIG. 6. In Figure 6, 20
is a comparator that converts the detected recording signal polarity determination mark into a pulse (FIG. 7b). When this pulse is input to the preset terminal of flip-flop 21, a latched signal (FIG. 7c) is output from the output. Reference numeral 22 denotes a recording signal polarity inversion logic, which controls normal rotation or inversion of the polarity of the output of the modulator 13 by the Q output of the flip-flop 21.

When the optical disk is attached to the disk motor 7, a controller (not shown) comprising a microcomputer detects this and outputs a disk motor rotation command to the disk motor. The flip-flop 21 is cleared at the rising edge of this rotation command.

The fifth mark indicates that it is an optical disc with an erasing function.
When there is a polarity reversal mark as shown in FIG. 17, the photodiode 19 detects a waveform as shown in FIG. 7a. This signal is converted to a reference voltage by the comparator 20.
It is compared and outputted at V _TH and converted into a pulse (Figure 7b).
This pulse output latches the flip-flop output Q. When the Q output is latched, the recording signal inversion logic 22 inverts the modulator output.

The state of recording signal polarity reversal is shown in FIGS. 8a to 8d. a is the output signal of the modulator, and b is its inverted output. c shows the condition of the recording pit, and d
is the reproduction signal output of the preamplifier when this recording pit is reproduced.

Even with such an erasable whitening recording type optical disc, it is possible to obtain a reproduced signal output having the same polarity as the modulator output during recording. Therefore, stable playback is possible using the same preamplifier, signal processing circuit, and demodulator as in the blackening recording method. As another embodiment of the present invention, a recording signal determination mark may be provided on the disk cartridge.

Effects of the Invention As described above, the present invention provides an optical disc with a recording signal polarity determination mark that can determine the polarity of the recording signal.
By detecting this judgment mark and determining the polarity of the signal to be recorded, and controlling the polarity of the recording signal to normal or reverse based on the judgment result, it is possible to differentiate between erasable and non-erasable optical discs. Even optical discs with different recording methods can be recorded and reproduced using the same recording and reproducing device.

[Brief explanation of the drawing]

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 black recording method and the reproduced signal waveform, and Figure 3 is a diagram showing the waveform of the reproduced signal. FIG. 4 is a plan view showing the structure of an optical disk 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 recording signal polarity determination mark, FIG. 6 is a block diagram showing the configuration of an optical recording/reproducing apparatus in an embodiment of the present invention, and FIG.
The figure is a waveform diagram showing the signals at each part of FIG. 6, and FIG. 8 is a diagram illustrating recording signal polarity inversion and reproduction signal. 1... Semiconductor laser, 8... Optical disk, 13
...Modulator, 17...Recording signal polarity determination mark, 1
8... Light emitting diode, 19... Photo diode.

Claims (1)

[Scope of Claims] 1. Means for focusing laser light into a minute spot light and irradiating it onto an optical disk to record a signal on the optical disk; and a first light beam having a polarity such that the portion where the signal is recorded has an increased reflectance. In order to distinguish between the disc and a second optical disc whose portion on which the signal has been recorded has a polarity in which the reflectance decreases, a recording signal polarity determination mark provided on the optical disc or disc jacket is attached by optical means or mechanically. a recording signal polarity determination mark detection means detected by a switch; and controlling the polarity of a recording signal recorded by modulating a laser beam on an optical disk to positive polarity or negative polarity according to the detection result of the recording signal polarity determination mark detection means. and controlling the polarity control means according to the detection result of the recording signal polarity determination mark detection means in order to distinguish and record the first optical disc and the second optical disc. An optical recording/reproducing device configured to perform. 2. Claim 1, wherein the first optical disc is a non-erasable write-once optical disc using a blackening recording method, and the second optical disc is an erasable rewritable optical disc using a whitening recording method. optical recording and reproducing device. 3. The optical recording and reproducing apparatus according to claim 1, wherein the recording signal polarity determination mark is provided on either the first optical disk or the second optical disk. 4. Claim 1, characterized in that the recording signal polarity determination mark is provided on either the disk jacket housing the first optical disk or the disk jacket housing the second optical disk. optical recording and reproducing device. 5. The optical recording and reproducing apparatus according to claim 1, wherein the recording signal polarity determination mark is provided inside or outside the information recording area of the optical disc. 6. The optical recording and reproducing apparatus according to claim 1, wherein the recording signal polarity determination mark is provided by a phase structure formed by unevenness of grooves on the optical disk. 7. The optical recording and reproducing apparatus according to claim 1, wherein the recording signal polarity determination mark is the presence or absence of a groove provided on the disk jacket.