JPH07262560A - Recording and reproducing device - Google Patents

Abstract

PURPOSE:To form a pit in fixed size on a disk having irregular reflectance of light by detecting a laser beam from a laser oscillator and reflected light from the disk, deciding a variation of the reflectance of the disk and controlling the laser oscillator via a light source control circuit. CONSTITUTION:The irradiating laser beam from the laser oscillator 9 and the reflected light from the disk 1 are detected by photodetectors 33 and 30e respectively. Based on these detected results, a variation in the reflectance is decided by a reflectance normalizing circuit 36, and the oscillator 9 is controlled by a laser control circuit 14 so that a quantity of recording light is corrected to make a quantity of absorbing light constant in an irradiated area of the disk 1. As a result, regular-sized pits are formed on an optical disk of irregularity in light reflectance due to data recorded in the past.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk recording / reproducing apparatus in which data is recorded by utilizing a phase change, and more particularly to a recording / reproducing apparatus capable of recording data on an optical disk in an overlapping manner.

[0002]

2. Description of the Related Art Japanese Patent Application No. 56-145530 discloses a technique for rewriting data already recorded as pits in a phase change medium with a single laser beam. In this technical device, regardless of the data on the phase change medium, a laser beam with a constant power that heats the new data recording portion to the melting point temperature is irradiated to the new data recording portion, and the other portion is heated to the crystallization temperature at the constant temperature. A power laser beam is emitted.

Further, Japanese Patent Application No. 4-152261 discloses a technique for recording on an optical disk with appropriate power. In this technique, the first detector detects the amount of light generated from the laser light source, and the second detector of the optical head detects the reflected light from the optical disc. The amount of light from the light source is divided by the output of the second detector by the output of the first detector to detect the area in which the reflectance or the magnetization direction of the perpendicular magnetic field changes on the optical disk, and the detection It is adjusted by feedbacking the result of signal processing on the signal to the light source control circuit.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the case of 145530, the optical absorptance of the phase change medium changes in the portion irradiated with the laser beam. Therefore, when a laser beam is applied to this area for overwriting data, a different amount of heat is accumulated in this area under the same power as the previous time, which changes the size of the pit. .

In the case of Japanese Patent Application No. 4-152261, no specific method or means for overwriting data is described. Further, this is intended to monitor the reflected light from the optical disk in real time and feed back the result to the light source control circuit, which requires a reaction time that causes a phase change after passing through the laser irradiation spot. There is a problem that it is not suitable for a recording medium.

It is an object of the present invention to provide a recording / reproducing apparatus which makes it possible to form pits of a constant size on an optical disk having a non-uniform light reflectance due to previously recorded data. .

[0007]

According to the present invention, a light source means for generating a reproducing light amount of light in a reproducing mode and selectively generating a light beam for selectively shifting from a reference light amount to a recording light amount according to information in a recording mode. And an optical mechanism that guides the light generated from the light source unit onto the optical disc, and that makes the region irradiated with the recording light amount of light have a light reflectance different from the surroundings.
First detection means for detecting the light generated from the light source means, second detection means for detecting the light reflected by the optical disc, light quantity of the light detected by the first detection means, and the second detection A light source control means for detecting a variation of the light reflectance in the irradiation area from the light quantity of the light detected by the means, and correcting the recording light quantity so that the light absorption amount becomes substantially uniform in the irradiation area. A recording / reproducing apparatus is provided.

[0008]

In this recording / reproducing apparatus, the first detecting means detects the light emitted from the light source means, the second detecting means detects the light reflected by the optical disk, and the light source control means detects the first detecting means. The fluctuation of the light reflectance is detected in the light irradiation area of the recording light quantity from the light quantity of the emitted light and the light quantity of the light detected by the second detection means, and the light absorption amount is made substantially uniform in this irradiation area. Correct the recording light intensity. Therefore, even if the light reflectance is not uniform due to the data recorded in the past, it is possible to form a pit having a light reflectance different from that of the surroundings on the optical disc with a constant size.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an optical disk device according to the first embodiment. That is, on the surface of the optical disc (information recording medium) 1, grooves (recording tracks) are formed spirally or concentrically.
Is rotated by the motor 2 at a constant speed, for example.
The motor 2 is controlled by a motor control circuit 18.

Recording / reproducing of information on / from the optical disc 1
This is performed by the optical head 3. This optical head 3
The linear motor 31 is fixed to a drive coil 13 that constitutes a movable portion, and the drive coil 13 is connected to a linear motor control circuit 17.

Further, a permanent magnet (not shown) is provided on the fixed portion of the linear motor 31, and the drive coil 13 is excited by the linear motor control circuit 17 so that the optical head 3 is substantially moved in the radial direction of the information recording medium 1. It is designed to move at a constant speed.

An objective lens 6 is held on the optical head 3 by a wire or a leaf spring (not shown). The objective lens 6 is moved in the focusing direction (the optical axis direction of the lens) by the drive coil 5 to drive the drive coil. Four
Tracking direction (direction orthogonal to the optical axis of the lens)
It is possible to move to.

The laser light generated by the semiconductor laser oscillator 9 driven by the laser control circuit 14 is
Collimator lens 11a, half prisms 11b, 11
c, irradiated onto the optical disc 1 through the objective lens 6,
The reflected light from the optical disc 1 is guided to the four-division photodetector 8 via the objective lens 6, the half prism 11c, the condenser lens 10a, and the cylindrical lens 10b.

The photodetector 8 is composed of photodetector cells 8a, 8b, 8c and 8d which are, for example, pin photodiodes. The output signal of the photodetector cell 8a of the photodetector 8 is added via the amplifier 12a to the adders 30a and 30a.
The output signal of the photo-detecting cell 8b is supplied to one end of the adders 30b and 30d via the amplifier 12b, and the output signal of the photo-detecting cell 8c is supplied to one end of the adder 30b, via the amplifier 12c. The output signal of the photo-detecting cell 8d supplied to the other end of 30c is added via the amplifier 12d to the adder 30.
It is adapted to be supplied to the other ends of a and 30d. (Also, the photodetector 8 may be of a two-division type) The output signal of the adder 30a is supplied to the inverting input terminal of the operational amplifier OP1, and the output of the adder 30b is supplied to the non-inverting input terminal of this operational amplifier OP1. Signal is supplied. The output signals of the amplifiers 12a-12d are supplied to the adder 30e. The output signal of the adder 30e is supplied to the reflectance normalization circuit 36. The output signal of the reflectance normalization circuit 36 is supplied to the laser control circuit 14 and the signal processing circuit 19.

The operational amplifier OP1 includes adders 30a and 30a.
A track difference signal is supplied to the tracking control circuit 16 according to the difference of b. The tracking control circuit 16 creates a track drive signal according to the track difference signal supplied from the operational amplifier OP1.

The track drive signal output from the tracking control circuit 16 is supplied to the drive coil 4 in the tracking direction. Further, the track difference signal used in the tracking control circuit 16 is the linear motor control circuit 1
It is designed to be supplied to 7.

The linear motor control circuit 17 responds to a track difference signal from the tracking control circuit 16 and a movement control signal from the CPU 23 to apply a voltage corresponding to the moving speed to a drive coil (conductor) 13 in a linear motor 31 described later. Is applied.

The linear motor control circuit 17 uses an electric change inside the drive coil 13 at the moment when the drive coil 13 in the linear motor 31 described later crosses a magnetic flux generated by a magnetic member (not shown). , Drive coil 1
A speed detection circuit (not shown) for detecting the relative speed between the magnetic member 3 and the magnetic member, that is, the moving speed of the linear motor 31 is provided.

The output signal of the adder 30c is supplied to the inverting input terminal of the operational amplifier OP2, and this operational amplifier OP2 is supplied.
The output signal of the adder 30d is supplied to the second non-inverting input terminal. As a result, the operational amplifier OP2 operates in the adder 30.
A signal related to the focus point is supplied to the focusing control circuit 15 according to the difference between c and 30d. The output signal of the focusing control circuit 15 is supplied to the focusing drive coil 5 and is controlled so that the laser light is always in perfect focus on the optical disc 1.

Each photodetecting cell 8a-8 of the photodetector 8 in the state where focusing and tracking are performed as described above.
The sum signal of the outputs of d, that is, the output signal from the adder 30e is reflected by the product of the change in the reflectance from the pits formed on the track (the part where the phase changes as the recording information) and the change in the light amount of the laser light. Has been done. This signal is supplied to the reflectance normalization circuit 36. Further, the laser light generated by the semiconductor laser oscillator 9 passes through the collimator lens 11 a, the half prism 11 b, and the lens 32, and the photodetector 33.
Be led to. The output signal of the photodetector 33 is the amplifier 3
It is supplied to the reflectance normalization circuit 36 via 5. The output signal of the amplifier 35 reflects the change in the light quantity of the laser beam, and is supplied to the signal processing circuit 19 as a signal whose reflectance is normalized by the reflectance normalizing circuit 36, and this signal processing circuit 19 is supplied. At, the recording information and address information (track number, sector number, etc.) are reproduced. Further, in front of the laser control circuit 14, a light emission reference signal generation circuit 34 as a modulation circuit for modulating a recording signal is provided. The output signal of the reflectance normalization circuit 36 is the laser control circuit 14
Is supplied to the semiconductor laser oscillator 9 to control the semiconductor laser oscillator 9 by correcting the change in the light amount required for recording due to the change in reflectance in the signal of the light emission reference signal generation circuit 34.

Further, the optical disk device has a focusing control circuit 15 and a tracking control circuit 1 respectively.
6. A D / A converter 22 used for exchanging information between the linear motor control circuit 17 and the CPU 23 is provided.

Further, the tracking control circuit 16 uses the CP
The objective lens 6 is moved according to a track jump signal supplied from U23 via the D / A converter 22, and the beam light is moved by one track.

Laser control circuit 14, focusing control circuit 15, tracking control circuit 16, linear motor control circuit 17, motor control circuit 18, signal processing circuit 19,
The recording signal generating circuit 34 and the like are connected to C via the bus line 20.
It is designed to be controlled by the PU23, and this C
The PU 23 is configured to perform a predetermined operation according to a program stored in the memory 24.

FIG. 2 shows the structure of the reflectance normalization circuit 36. The division circuit 37 and the analog switch circuit 38 are shown in FIG.
And a limiter circuit 39. Photo detector 8
The output signal from the adder 30e as the sum signal of the outputs of the respective photodetection cells 8a to 8d is supplied to the division circuit 37, and the signal from the amplifier 35 as the output signal from the photodetector 33 also passes through the limiter circuit 39. It is supplied to the division circuit 37 via the.

The division circuit 37 performs division using the sum signal of the photodetector 8 as the numerator and the output signal of the photodetector 33 as the denominator, and the amount of laser light emitted from the semiconductor laser oscillator 9 is emitted. Is removed and only the change in the reflectance of the optical disc is output. The output signal of the division circuit 37 is supplied to the laser control circuit 14 only during recording by the signal of the CPU 23 through the analog switch circuit 38.

FIG. 3 shows the structure of the laser control circuit 14, which is composed of a light emission signal generation circuit 40 and a light emission drive circuit 41. The light emission drive circuit 41 includes a light emission control circuit 42, a light emission limiting circuit 43, and a current drive circuit 44.

The output signal of the reflectance normalization circuit 36 is supplied to the light emission signal generation circuit 40, and the light emission reference signal generation circuit 34.
Is also supplied to the light emission signal generation circuit 40.

The light emission signal generation circuit 40 outputs the signal L from the light emission reference signal generation circuit 34 and the signal a from the reflectance normalization circuit 36 (when the reflectance increases due to recording) or c.
From (when the reflectance decreases due to recording), P = L + ka
+ B or P = L-kc + d (P: amount of light emission, k: coefficient of reflectance, b, d: correction value of power) is calculated, and the light emission reference signal is corrected by the reflectance. .

The output signal of the light emission signal generation circuit 40 is supplied to the light emission control circuit 42, and the output signal of the amplifier 35 is also supplied to the light emission control circuit 42. The light emission control circuit 42 amplifies the output signal of the amplifier 35, that is, the monitor signal of the light emission amount, takes the difference from the output signal of the light emission signal generation circuit 40, that is, the light emission reference signal, and obtains the light emission reference signal and the light emission amount. The output of the light emission control circuit 42 is supplied to the light emission limiting circuit 43, and a signal for limiting the light emission amount of the semiconductor laser oscillator 9 so as not to exceed the maximum rating is output by the current drive circuit 44. To drive the semiconductor laser oscillator 9 by limiting the current supplied to the semiconductor laser oscillator 9.

Next, a concrete circuit of each circuit will be described.

The division circuit 37 is, for example, a division circuit using an FET as shown in FIG. 4, and an AGC as shown in FIG.
(Automatic gain control) Division circuit using OP amplifier with function,
It is composed of a division circuit using a multiplier as shown in FIG. In FIG. 6, division is performed using the output from the adder 30e as the numerator and the output from the amplifier 35 as the denominator.

FIG. 7 is a circuit diagram of the limiter circuit 39. The voltage V1 is resistance-divided into R2 / (R1 + R2) .times.V1 which is one diode forward voltage lower than the voltage VL = R2 / (R1
When the output voltage of the amplifier 35 becomes equal to + R2) .times.V1 -VD, the denominator of the division circuit 37 is set to VL.

FIG. 8 is a circuit diagram of the light emission signal generation circuit 40.
When the reflectance of the optical disc 1 is increased by recording from the signal from the light emission reference signal generation circuit 34, the signal from the reflectance normalization circuit 36 is subtracted and the optical disc 1 is recorded.
In the case where the reflectance of the signal decreases, the signal from the reflectance normalization circuit 36 is added.

FIG. 9 is a circuit diagram of the light emission control circuit 42, in which the light emission amount signal from the amplifier 35 from the light emission signal generation circuit 40 is amplified by OP1 and subtracted by OP2. FIG. 10 is a circuit diagram of the light emission control circuit 43. When the output signal from the light emission control circuit 42 becomes equal to or higher than the Zener voltage VZ of the Zener diode, the signal output to the current drive circuit 44 is set to VZ.

FIG. 11 is a circuit diagram of the current driving circuit 44. For example, the output signal from the light emission limiting circuit 43 is supplied to the transistor through the buffer amplifier, the transistor amplifies the current, and the semiconductor laser oscillator 9 It is designed to pass an electric current.

Next, the overlap recording operation of the disk device of this embodiment will be described.

12 and 13 show various signals generated in this overwriting operation.

In the case of an optical disc whose reflectance increases by recording: When data such as (b) is overwritten on a track of the optical disc 1 on which data such as (a) of FIG. The data of (b) is sent from the line 20 to the light emission reference signal generation circuit 34, and the light emission reference signal generation circuit 34 records the recording power and the bias power so that the position of "1" becomes the edge of the pit as shown in (c). A signal that switches between is generated.

In the reflectance normalization circuit 36, the amount of light reflected from the disk 1 is used as the numerator and the amount of light emitted from the semiconductor laser oscillator 9 is used as the denominator for division, and a signal corresponding to the reflectance shown in FIG. Is generated. Based on this signal and the output signal of the light emission reference signal generation circuit 34, the light emission signal generation circuit 40 outputs P
= L + ka + b is calculated and a signal for increasing the amount of light emission according to the reflectance is output in the portion where there is a pit before (e), and the semiconductor laser oscillator 9
By emitting light, a pit like (f) is formed on the optical disc 1.

In the case of an optical disc whose reflectance decreases due to recording: data such as (b) is recorded over the track of the optical disc 1 where the data shown in (a) of FIG. 13 has been previously recorded. At this time, the data (b) is sent from the bus line 20 to the light emission reference signal generation circuit 34, and the light emission reference signal generation circuit 34 generates a signal as shown in (c).

In the reflectance normalization circuit 36, the amount of light reflected from the disk 1 is used as the numerator, and the amount of light emitted from the semiconductor laser oscillator 9 is used as the denominator for division. A signal corresponding to the reflectance shown in FIG. Is generated. This signal is calculated from the output signal of the light-emission reference signal generation circuit 34 by the light-emission signal generation circuit 40 to calculate P = L-kc + d. A signal for reducing the light emission amount is output, and the semiconductor laser oscillator 9 is caused to emit light as in this signal, so that pits (f) are formed on the optical disc 1.

According to the above-described first embodiment, the difference in reflectance depending on the previously recorded data, that is, the difference in light absorptance is detected, and the luminescence amount is corrected to perform recording. The shape can be constant.

Further, if the reflectance is fed back during reading, it becomes possible to prevent the data from becoming unreadable.

Further, when the amount of reflected light is divided by the amount of emitted light, the result of division is prevented from becoming large if the amount of emitted light is close to zero.

Further, when the reflectance of the optical disk is low due to a defect or the like, the current value is prevented from being excessively increased to destroy the LD in order to increase the light emission amount.

The second embodiment of the present invention will be described below.

FIG. 14 schematically shows the optical head of the optical disc apparatus according to the second embodiment and a portion related to signal processing. The optical disk device of the second embodiment has the same configuration as that of the first embodiment except for the points described below. Therefore, the same parts are represented by the same reference numerals, and duplicated description will be omitted.

Unlike the first embodiment, the laser control circuit 14 is constructed as shown in FIG. That is, the output of the reflectance normalization circuit 36 and the output of the light emission reference signal generation circuit 34 are supplied to the reflectance control circuit 44. Reflectance control circuit 4
Reference numeral 4 indicates the difference between the signal from the light emission reference signal generation circuit 34 and the reflectance signal from the reflectance normalization circuit 36. The semiconductor laser oscillator 9 corresponds to the reflectance change in real time. Light up.

FIG. 16 shows an example of the reflectance control circuit 44. When the reflectance increases, OP3 amplifies the reflectance signal from the reflectance normalization circuit 36, OP4 takes the difference from the data signal from the light emission reference signal generation circuit 34, and supplies it to the light emission drive circuit 41.

When the reflectance decreases, OP3 amplifies the reflectance signal from the reflectance normalization circuit 36 and OP4
Is summed with the data signal from the light emission reference signal generation circuit 34 and supplied to the light emission drive circuit 41.

Next, the overlap recording operation of the disk device of this embodiment will be described.

17 and 18 show various signals generated in this overwriting operation.

In the case of an optical disc whose reflectance increases by recording: When data such as (b) is overwritten on a track of the optical disc 1 on which data such as (a) of FIG. The data of (b) is sent from the line 20 to the light emission reference signal generation circuit 34, and the light emission reference signal generation circuit 34 records the recording power and the bias power so that the position of "1" becomes the edge of the pit as shown in (c). A signal that switches between is generated.

In the reflectance normalization circuit 36, the amount of light reflected from the disk 1 is used as the numerator and the amount of light emitted from the semiconductor laser oscillator 9 is used as the denominator for division, and a signal corresponding to the reflectance shown in FIG. Is generated. From this signal and the output signal of the light emission reference signal generation circuit 34, the light emission signal generation circuit 40 outputs the signal (e) of the difference in reflectance change with respect to the output signal of the light emission reference signal generation circuit 34, and the semiconductor laser oscillator 9 emits light. By doing so, a pit like (f) is formed on the optical disc 1.

Further, in the case of an optical disc whose reflectance decreases by recording: data such as (b) is overwritten on the track of the optical disc 1 on which the data shown in (a) of FIG. 18 has been previously recorded. At this time, the data (b) is sent from the bus line 20 to the light emission reference signal generation circuit 34, and the light emission reference signal generation circuit 34 generates a signal as shown in (c).

Further, in the reflectance normalization circuit 36, the amount of light reflected from the disk 1 is used as the numerator, and the amount of light emitted from the semiconductor laser oscillator 9 is used as the denominator for division, and a signal corresponding to the reflectance shown in FIG. Is generated. This signal is output from the light emission reference signal generation circuit 34, and the light emission signal generation circuit 40 outputs a signal (e) of the difference in reflectance change with respect to the output signal of the light emission reference signal generation circuit 34. By emitting light, a pit like (f) is formed on the optical disc 1.

According to the second embodiment, the difference in the reflectance of the previously recorded data and the change in the reflectance due to the currently emitted light are detected to correct the light emission amount for recording. Therefore, the shape of the pit can be made constant.

The third embodiment of the present invention will be described below.

FIG. 19 schematically shows a portion related to the optical head and signal processing of the optical disk device according to the third embodiment. The optical disk device of the third embodiment is configured similarly to the first and second embodiments except for the points described below. Therefore, the same parts are represented by the same reference numerals, and duplicated description will be omitted.

Unlike the first and second embodiments, the output signal from the amplifier 35 is a low pass filter (L
It is supplied to the laser control circuit 14 via the PF) 45. As a result, changes in the amount of low-frequency light emission due to changes in the temperature of the semiconductor laser oscillator 9 and the like can be observed. Further, the laser control circuit 14 and the semiconductor laser oscillator 9
By inserting a high frequency superimposing circuit 46 between and, the high frequency is superposed on the current for driving the semiconductor laser oscillator 9, so that the change in the light emission amount of the semiconductor laser oscillator 9 due to the returning light can be expected. There is.

Next, FIG. 20 shows an example of a high frequency superimposing circuit. In this way, by superimposing the signal of the transistor oscillator 47 on the signal from the laser control circuit 14 via the capacitor, the light emission of the semiconductor laser oscillator 9 is stabilized.

The overlap recording operation of this disk device is shown in FIG.
18 and FIG. 18 and is the same as that described in the second embodiment. Therefore, the description thereof is omitted.

According to the third embodiment, when the amount of light emitted from the LD changes at a high frequency due to the influence of the return light, the high frequency is superimposed on the drive current of the LD and the light is emitted at a high frequency, so that the data is equal to or less than the data band. It emits light stably.

[0065]

According to the present invention, the light emission amount is adjusted by detecting the light reflectance, that is, the light absorptance that has changed depending on the previously recorded data. A recording portion can be formed.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of an optical disc device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of the reflectance normalization circuit shown in FIG. 1 in more detail.

3 is a block diagram showing the configuration of the laser control circuit shown in FIG. 1 in more detail.

4 is a circuit diagram showing a division circuit using an FET as an example of the division circuit shown in FIG.

5 is a diagram showing a division circuit using an OP amplifier with an AGC function as an example of the division circuit shown in FIG.

FIG. 6 is a diagram showing a division circuit using a multiplier as an example of the division circuit shown in FIG.

FIG. 7 is a circuit diagram showing the configuration of the limiter circuit shown in FIG. 2 in more detail.

8 is a circuit diagram showing the configuration of the light emission signal generation circuit shown in FIG. 3 in more detail.

9 is a circuit diagram showing the configuration of the light emission control circuit shown in FIG. 3 in more detail.

FIG. 10 is a circuit diagram showing the configuration of the light emission limiting circuit shown in FIG. 3 in more detail.

11 is a circuit diagram showing in more detail the configuration of a current drive circuit 44 shown in FIG.

FIG. 12 is a waveform chart of various signals generated in an overwriting operation performed in the case of an optical disc whose reflectance increases by recording.

FIG. 13 is a waveform chart of various signals generated in an overwriting operation performed in the case of an optical disc whose reflectance is reduced by recording.

FIG. 14 is a circuit diagram schematically showing an optical head and a portion related to signal processing of an optical disc device according to a second embodiment of the present invention.

15 is a block diagram showing the configuration of the laser control circuit shown in FIG. 14 in more detail.

16 is a circuit diagram showing an example of the reflectance control circuit shown in FIG.

FIG. 17 is a waveform diagram of various signals generated in an overwriting operation performed in the case of an optical disc whose reflectance increases by recording.

FIG. 18 is a waveform chart of various signals generated in an overwriting operation performed in the case of an optical disc whose reflectance is reduced by recording.

FIG. 19 is a circuit diagram schematically showing an optical head and a portion related to signal processing of an optical disc device according to a third embodiment of the present invention.

20 is a circuit diagram showing an example of the high frequency superimposing circuit shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Motor, 3 ... Optical head, 8 ... Photodetector, 9 ... Semiconductor laser oscillator, 12a-12d ... Amplifier, 14 ... Laser control circuit, 19 ... Signal processing circuit, 2
3 ... CPU 23, 24 ... Memory, 30a-30e ... Adder, 33 ... Photodetector, 34 ... Emission reference signal generation circuit, 3
5 ... Amplifier, 36 ... Reflectance normalization circuit, 37 ... Division circuit, 38 ... Analog switch circuit, 40 ... Emission signal generation circuit, 41 ... Emission drive circuit, 42 ... Emission control circuit, 43
... light emission limiting circuit, 44 ... current driving circuit, 45 ... low-pass filter, 46 ... high-frequency superimposing circuit, 47 ... high-frequency oscillator.

Claims (15)

[Claims] 1. Light source means for generating a reproduction light amount of light in a reproduction mode and light for selectively shifting from a reference light amount to a recording light amount according to information in a recording mode; and light generated by the light source means. On the optical disc,
An optical mechanism that makes the region irradiated with the recording light amount of light have a light reflectance different from that of the surroundings, a first detection unit that detects the light generated from the light source unit, and detects the light reflected by the optical disc. A second detection unit, a variation in light reflectance in the irradiation region is detected from the light amount of the light detected by the first detection unit and the light amount of the light detected by the second detection unit, and the light is detected in the irradiation region. A recording / reproducing apparatus, comprising: a light source control unit that corrects the recording light amount so that the absorption amount is substantially uniform. 2. The light source control means includes a normalization means for normalizing the reflectance of the disc from the light quantity of the light detected by the first detection means and the light quantity of the light detected by the second detection means. Reflection of the optical disc from a light emission reference signal generating means for generating a reference signal for determining the light emission amount of the light source means, a light emission reference signal from the light emission reference signal generating means and a reflectance normalization signal from the normalizing means. A light emission signal generating means for generating a light emission signal corresponding to the rate variation, and a driving means for driving the light source means in response to the light emission signal from the light emission signal generating means and the detection signal from the first detection means are included. The recording / reproducing apparatus according to claim 1, wherein: 3. The recording / reproducing apparatus according to claim 2, wherein the light source control means includes a switch means for disconnecting the normalization means from the light emission signal generation means in the reproduction mode. 4. The normalizing means includes a dividing means for dividing the light quantity of the light detected by the second detecting means by the light quantity of the light detected by the first detecting means, and the driving means comprises: First
3. The recording / reproducing apparatus according to claim 2, further comprising limiter means for setting the light quantity from the first detection means to a constant value when the light quantity obtained from the detection means approaches zero. 5. The recording / reproducing apparatus according to claim 2, wherein the light source control means includes compensating means for canceling a low-frequency fluctuation of the light emission amount of the light source means based on the light amount detected by the first detecting means. 6. The light source control means includes high frequency superimposing means for superimposing a high frequency on the signal from the driving means.
The recording / reproducing device according to. 7. The information is recorded / recorded on an optical disc having a track whose reaction time is long by changing the reflectance by recording.
A light emitting means for emitting light for reproduction, a first detecting means for detecting light from the light emitting means, a recording / reproducing means for recording / reproducing information by condensing light on the optical disk, and the optical disk at the same time An optical head having a second detection means for detecting reflected light from the optical disc; and a reflectance of the optical disc from a detection signal generated by the first detection means and a detection signal from the second detection means. Normalizing means for normalizing, light emission reference signal generating means for generating a reference signal for determining the light emission amount of the light emitting means, light emission reference signal from the light emitting reference signal generating means, and normalization of reflectance from the normalizing means. A light-emission signal generation unit that generates a light-emission signal corresponding to the reflectance of the previously recorded information of the optical disc from the light-emission signal, the light-emission signal from the light-emission signal generation unit, and the first detection device. An optical disk recording / reproducing apparatus comprising: a driving unit that drives the light emitting unit so as to cancel the difference between the light emitting signal and the actual light emitting amount based on the detection signal generated by the stage. 8. The optical head further comprises a first amplifier circuit for current-voltage converting and amplifying a detection signal from the first detector, and a current-voltage converting detection signal from the second detector. A second amplifier circuit for converting and amplifying, wherein the normalizing means performs division using the detection signal from the first amplifier circuit as a denominator and the detection signal from the second amplifier circuit as a numerator. It has a division circuit for normalizing the reflectance of the optical disk, and an analog switch circuit for connecting the normalization signal from the division circuit with a recording / reproduction switching signal from the CPU during recording and disconnecting it during reproduction. The light emission reference signal generation means has means for generating the light emission reference signal in response to a data signal at the time of recording / reproducing and recording, and the light emission signal generation means is a light emission reference from the light emission reference signal generation means. Signal and the A driving circuit for calculating an appropriate value of the amount of light emission corresponding to the reflectance of the optical disc from a signal from the analog switch circuit; and the drive means for outputting the light emission signal from the calculation means and the first amplification circuit. And a current drive circuit for supplying a current corresponding to the light emission control signal from the light emission control circuit to the light emitting means. The recording / reproducing apparatus according to claim 7, wherein: 9. The light emitting means has a laser light source for emitting laser light for recording / reproducing information on / from an optical disk using a phase change or diffusion film, and the first detecting means is a detection using a pin photodiode. The first amplifier circuit has a circuit using an operational amplifier, a transistor, or a combination thereof, the recording / reproducing means has an objective lens actuator, and the second detecting means has a Or a detector using a pin photodiode divided into four, the second amplification circuit has an operational amplifier, a transistor, or a circuit in which these are combined, and the division circuit has a multiplier, an FET, or an automatic circuit. The normalizing means has a circuit using an operational amplifier with a gain control function, and the normalizing means detects a detection signal from the first amplifying circuit serving as a denominator in the dividing circuit. When it comes close to (b), it further has a limiter circuit for making the value of this denominator a certain constant value, and when the reflectance decreases due to recording, the formula P =
According to L-ka + b (P: amount of emitted light, L: emission reference value, k: coefficient of reflectance, a: normalized value of reflectance, b: correction value of power), the formula P is used when the reflectance increases by recording. = L
+ Kc + d (P: light emission amount, L: light emission reference value, k: reflectance coefficient, c: reflectance normalization value, d: power correction value)
A circuit using an operational amplifier for calculating an appropriate value of the amount of light emission according to the above, the light emission control circuit has a circuit using an operational amplifier, and the current drive circuit has a circuit using a transistor for causing a current to flow to a light emitting means. 9. The recording / reproducing apparatus according to claim 8, further comprising a circuit using a Zener diode that limits this current. 10. A light emitting means for emitting light for recording / reproducing information on an optical disc having a track whose reaction time is short by changing the reflectance by recording, and a first light detecting means for detecting the light from this light emitting means. A detecting means, and a recording / reproducing means for recording / reproducing information by focusing light on the optical disc,
At the same time, an optical head having a second detection means for detecting the reflected light from the optical disc, a detection signal generated by the first detection means and a detection signal from the second detection means are used to detect the optical disc. Normalization means for normalizing the reflectance; light-emission reference signal generation means for generating a reference signal that determines the amount of light emitted by the light-emission means; light-emission reference signal from the light-emission reference signal generation means and reflection from the normalization means. Reflectance control means for generating a light emission signal corresponding to the reflectance change of the optical disc from the normalized signal of the rate, the light emission signal from the reflectance control means, and the detection generated by the first detection means. An optical disk recording / reproducing apparatus comprising: a driving unit that drives the light emitting unit so as to cancel the difference between the light emitting signal and the actual light emitting amount based on the signal. 11. The optical head further comprises a first amplifier circuit for current-voltage converting and amplifying a detection signal from the first detector, and a detection signal from the second detector with a current-voltage.
A second amplifying circuit for voltage-converting and amplifying, wherein the normalizing means divides the detection signal from the first amplifying circuit as a denominator and the detection signal from the second amplifying circuit as a numerator. There is provided a division circuit for normalizing the reflectance of the optical disc and an analog switch circuit for connecting the normalization signal from the division circuit at the time of recording by the recording / reproduction switching signal from the CPU and disconnecting at the time of reproduction. The light emission reference signal generation means has a light emission reference signal generation circuit for generating the light emission signal corresponding to a data signal at the time of recording / reproducing and recording, and the reflectance control means has the light emission reference signal generation means. A light emission reference signal from the analog switch circuit and a signal from the analog switch circuit to change the light emission amount in accordance with the light reflectance of the optical disc. A light emission control circuit for controlling so as to cancel the difference between the light emission signal and the actual light emission amount based on the light emission signal from the light emission control circuit and the detection signal from the first amplifier circuit, and a current corresponding to the light emission control signal from the light emission control circuit. 11. The recording / reproducing apparatus according to claim 10, further comprising: a current drive circuit that causes a current to flow through the light emitting means. 12. The light emitting means has a laser light source for emitting laser light for recording / reproducing information on / from an optical disc using a phase change or diffusion film, and the first detecting means is a detection using a pin photodiode. The first amplifier circuit has a circuit using an operational amplifier, a transistor, or a combination thereof, the recording / reproducing means has an objective lens actuator, and the second detecting means has a Or a detector using a pin photodiode divided into four, the second amplification circuit has an operational amplifier, a transistor, or a circuit in which these are combined, and the division circuit has a multiplier, an FET, or an automatic circuit. The normalizing means has a circuit using an operational amplifier with a gain control function, and the normalizing means outputs a detection signal from the first amplifying circuit serving as a denominator in the dividing circuit. When it approaches zero, it further has a limiter circuit for making the value of this denominator a certain constant value, the reflectance control circuit has a circuit using an operational amplifier, and the light emission control circuit has a circuit using an operational amplifier. 9. The recording / reproducing apparatus according to claim 8, wherein the current drive circuit has a circuit using a transistor for causing a current to flow through the light emitting means and a circuit using a Zener diode for limiting the current. 13. A light emitting means for emitting light for recording / reproducing information on an optical disk having a track whose reaction time is short by changing the reflectance by recording, and a first light detecting means for detecting light from this light emitting means. A detecting means, and a recording / reproducing means for recording / reproducing information by focusing light on the optical disc,
At the same time, an optical head having a second detection means for detecting the reflected light from the optical disc, a detection signal generated by the first detection means and a detection signal from the second detection means are used to detect the optical disc. Normalization means for normalizing the reflectance; light-emission reference signal generation means for generating a reference signal that determines the amount of light emitted by the light-emission means; light-emission reference signal from the light-emission reference signal generation means and reflection from the normalization means. Reflectance control means for generating a light emission signal corresponding to the reflectance change of the optical disc from the normalized signal of the rate, the light emission signal from the reflectance control means, and the detection generated by the first detection means. A driving means for driving the light emitting means so as to cancel a change in the light emission amount at a low frequency due to a temperature change of the light emitting means, and a driving means for causing the light emitting means to emit light. Recording and reproducing apparatus of an optical disc, characterized by comprising a high-frequency superimposing means for superimposing a high frequency signal. 14. The optical head further comprises a first amplifier circuit for current-voltage converting and amplifying a detection signal from the first detector, and a detection signal from the second detector with a current-voltage.
A second amplifying circuit for voltage-converting and amplifying, wherein the normalizing means divides the detection signal from the first amplifying circuit as a denominator and the detection signal from the second amplifying circuit as a numerator. There is provided a division circuit for normalizing the reflectance of the optical disc and an analog switch circuit for connecting the normalization signal from the division circuit at the time of recording by the recording / reproduction switching signal from the CPU and disconnecting at the time of reproduction. The light emission reference signal generation means has a light emission reference signal generation circuit for generating the light emission signal corresponding to a data signal at the time of recording / reproducing and recording, and the reflectance control means has the light emission reference signal generation means. A light emission reference signal from the analog switch circuit and a signal from the analog switch circuit to change the light emission amount in accordance with the light reflectance of the optical disc. A light emission control circuit for controlling so as to cancel a change in the light emission amount at a low frequency due to a temperature change of the light emitting means, and the light emission control circuit from the light emission control circuit. 14. The recording / reproducing apparatus according to claim 13, further comprising a current drive circuit that causes a current corresponding to a light emission control signal to flow through the light emitting means. 15. The light emitting means has a laser light source for emitting laser light for recording / reproducing information on / from an optical disc using a phase change or diffusion film, and the first detecting means is a detection using a pin photodiode. The first amplifier circuit has a circuit using an operational amplifier, a transistor, or a combination thereof, the recording / reproducing means has an objective lens actuator, and the second detecting means has a Or a detector using a pin photodiode divided into four, the second amplification circuit has an operational amplifier, a transistor, or a circuit in which these are combined, and the division circuit has a multiplier, an FET, or an automatic circuit. The normalizing means has a circuit using an operational amplifier with a gain control function, and the normalizing means outputs a detection signal from the first amplifying circuit serving as a denominator in the dividing circuit. When it approaches zero, it further has a limiter circuit for making the value of this denominator a certain constant value, the reflectance control circuit has a circuit using an operational amplifier, and the light emission control circuit has a circuit using an operational amplifier. The current drive circuit includes a circuit using a transistor that causes a current to flow through the light emitting means, a circuit using a Zener diode that limits the current, and a transistor oscillation circuit that superimposes a high frequency on the current flowing through the light emitting means. The recording / reproducing apparatus according to claim 14, wherein the recording / reproducing apparatus is a recording / reproducing apparatus.