JPH05225566A - Optical disk device - Google Patents

Abstract

PURPOSE:To provide an optical disk device capable of setting optionally a pulse width by a single pulse width setting circuit and recording with a stable pulse width. CONSTITUTION:A clock 39 synchronizing with a recording data signal 38 is outputted by a recording signal output device 33. A triangular wave generator 34 to which the clock 39 is inputted generates a triangular wave 40. A DC constant voltage 41 output from a reference voltage generator 36 and the triangular wave 40 are compared by an optional pulse width setting device 35 and the pulse width is set optionally. Then AND between the output signal 42 of the optional pulse width setting device 35 and the recording data signal 38 is operated by an AND gate 44 and recording is performed with the recording pulse outputted by a semiconductor laser oscillator 1. Thus, the pulse width is set optionally by a single recording width setting device 32 and recording with high reliability is performed by the pulse width in accordance with the kind of an optical disk or the position in the radial direction of the optical disk.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device which is used as an external storage device of a computer and which is capable of recording, reproducing and erasing data.

[0002]

2. Description of the Related Art In recent years, an optical disk device has been attracting attention as a storage device capable of recording a large amount of information and capable of repeating reproduction and erasing. 2. Description of the Related Art Conventionally, an optical disk device that records or reproduces information on a write-once or rewritable optical disk reproduces with a relatively small continuous optical output from a semiconductor laser, and also with a relatively large intermittently changing optical output on an optical disk. To record. The time to irradiate the laser beam for recording varies depending on the type of the optical disc. Even for the same optical disc, the time to irradiate the laser beam depending on the radial position, that is, the pulse width is changed to ensure the recording and the reliability of the recorded information. It may be necessary to improve the

Recording on the optical disk as described above is shown in FIG.
This is performed by the circuit shown in FIG. The operation of this circuit will be described below. A semiconductor laser oscillator 1 as a light output means for generating a laser beam includes a transistor 2,
3 is driven. The collectors of the transistor 2 for generating reproducing light and the transistor 3 for generating recording light are connected to one terminal of the semiconductor laser oscillator 1, and the other terminal of the semiconductor laser oscillator 1 is grounded. The emitter of the transistor 2 is grounded via the resistor 5, and the emitter of the transistor 3 is connected to the resistor 6
Grounded through.

A photodiode 7 corresponding to the semiconductor laser oscillator 1 is for monitoring laser light, and an optical output monitor signal which is an output thereof is input to a laser reproduction light control circuit 8 to perform feedback control. The optical output of the semiconductor laser oscillator 1 is kept constant. A voltage signal output from the laser reproduction light control circuit 8 is input to the base of the transistor 2 during reproduction, and a voltage signal obtained by holding the voltage value input during reproduction immediately before recording in a sample hold circuit or the like is recorded. It is adapted to be input, and these two inputs can be switched depending on whether recording or reproduction is performed. In both recording and reproduction, feedback control is performed based on the optical output level during reproduction.

Further, the transistor 3 is for generating a laser beam having a high light intensity at the time of recording, and a voltage for recording is sent from the recording power reference voltage generating circuit 9 to its base. .. The base of the transistor 3 is connected to the collector of the transistor 4, and the emitter of the transistor 4 is grounded.
The pulse width setting circuit 10 is provided at the base of the transistor 4.
A recording pulse signal corresponding to the recording data signal output by a and 10b is transmitted.

The pulse width setting circuits 10a and 10b adjust each pulse width of the recording data signal according to the recording data to a predetermined width and output it as a recording pulse signal. As shown in FIG. , 14, a NAND gate 12, a variable resistor R, a capacitor C and a diode D.

When a signal having a pulse width W1 as shown in FIG. 6 is input to the pulse width setting circuits 10a and 10b, one of the input signals is inverted by the inverter 11 as shown in FIG. It is sent to one of the input terminals.
The other input signal is the inverter 13 as shown in FIG.
Is inverted by the CR time constant circuit and is delayed by the time t by the CR time constant circuit and sent to the inverter 14. And FIG.
As shown in, the signal inverted by the inverter 14 is
It is sent to the other input terminal of the D gate 12. And NA
A logical product is taken by the ND gate 12 and further inverted to output a signal whose pulse width is adjusted to W2.

The pulse width setting circuits 10a and 10b
The transistor 4 is turned on in response to the recording pulse signal output by
Transistor 3 turns ON / OFF by turning N / OFF.
The semiconductor laser oscillator 1 is driven by the superimposed signals of the collectors of the transistor 2 and the transistor 3 to output laser light of intermittent high intensity, thereby recording information on the optical disk. ..

Further, the pulse width setting circuit 10a or the pulse width setting circuit 10b used for the recording operation is selected by the selection signals 16 and 17 from the control circuit 15.
That is, as shown in FIG. 4, the selection signals composed of the AND gates 18 and 19 and the inverter 20 are connected to the selection signals 16 and 1.
If a 7 is sent, either AND gate 18, 19
Becomes active and passes the recording data signal.

Then, the output of the pulse width setting circuit 10a or the pulse width setting circuit 10b to which the recording data signal is sent is sent to the base of the transistor 4 as a recording pulse signal,
It will be recorded.

As described above, a plurality of pulse width setting circuits 10a and 10b for setting the irradiation time of the pulsed recording light beam output from the semiconductor laser oscillator 1, that is, the pulse width are provided, and the plurality of recording pulse setting circuits 10a are provided. , 10b, for example, one pulse width setting circuit 10a or pulse width setting circuit 10b is selected according to the type of optical disc, and recording of a predetermined pulse width is performed using the selected pulse width setting circuits 10a, 10b. The recording is performed by generating a light beam so that the optimum pulse width can be recorded according to the type of the optical disc, and the recording can be performed while changing the pulse width according to the radial position of the optical disc.

[0012]

However, in the pulse width setting circuits 10a and 10b having the above-mentioned conventional structure, since the pulse width is fixed at a constant value, a plurality of N optical discs or a plurality of N optical discs are arranged depending on the radial positions of the optical discs. When it is desired to set different pulse widths, N pulse width setting circuits are required, and the size of the selection circuit also becomes large. Therefore, the circuit size of the pulse width setting portion becomes large as a whole and the cost increases. I had. Further, since the pulse width setting circuits 10a and 10b delay the recording data signal by the CR time constant of the resistors R and C, variations in the resistors R and C,
There is a problem in that the pulse width cannot be set stably due to temperature changes and changes over time.

The present invention solves the above conventional problems, and an object of the present invention is to provide an optical disk device capable of setting an arbitrary pulse width with a single pulse width setting circuit and further setting a stable pulse width. It is a thing.

[0014]

In order to solve the above problems, an optical disk device of the present invention is a recording signal output device for outputting a recording data signal and a clock synchronized with the recording data signal, and a triangular wave for generating a triangular wave from the clock. From the generator, a reference voltage output device that outputs a reference DC voltage, an arbitrary pulse width setting device that compares the triangular wave and the reference voltage to set the pulse width arbitrarily, and from the arbitrary pulse width setting device The AND gate which outputs the recording pulse by taking the logical product of the output signal and the recording signal, and the optical output means which performs the recording by the recording pulse are provided.

[0015]

With the above construction, the pulse width can be arbitrarily changed and recorded by the single pulse width setting means according to the kind of the different kinds of optical disks or the radial position of the optical disks.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. In addition, the same reference numerals are given to those having the same functions as the conventional ones.

FIG. 2 shows a schematic structure of an optical disk device according to an embodiment of the present invention. Reference numeral 21 is an optical disk, and this optical disk 21 is rotated by a spindle motor 22. This spindle motor 22
Start of rotation according to a control signal from the motor control circuit 23,
Stop and rotation speed are controlled. An optical pickup 24 is arranged below the optical disc 21, and the optical pickup 24 records and reproduces information on and from the optical disc 21, and includes an optical system and a drive system. The optical system of the optical pickup 24 is
The semiconductor laser oscillator 1 is composed of a lens and prisms 25 for condensing laser light on the optical disk 21, a photodetector 26 for converting reflected light into an electric signal, a photodiode 7, and the like. The drive system is composed of a magnet and a coil 27, and a light spot is targeted by a control signal from a focus control circuit 28 that follows the surface shake accompanying the rotation of the optical disk 21 and a control signal from a tracking control circuit 29 that follows the track shake. It is designed to be maintained in position.

The electrical signal from the photodetector 26 is also sent to the information detector 30. Information detector 30
The electric signal is converted into a reproduction signal reflecting the information of the optical disk 21, and the reproduction signal is sent to the binarization circuit 31. The binarization circuit 31 is composed of, for example, a comparator, and binarizes the analog signal output from the adder by comparing it with a predetermined threshold voltage. The reproduced digital signal binarized by the binarization circuit 31 is sent to the control circuit 15.

A semiconductor laser oscillator 1 for generating laser light is driven by transistors 2 and 3. The collectors of the transistor 2 for generating reproducing light and the transistor 3 for generating recording light are semiconductor laser oscillator 1 respectively. Is connected to one terminal and the other terminal of the semiconductor laser oscillator 1 is grounded. The emitter of the transistor 2 is grounded via the resistor 5, and the emitter of the transistor 3 is grounded via the resistor 6.

A photodiode 7 facing the semiconductor laser oscillator 1 is for monitoring laser light, and an optical output monitor signal which is an output thereof is input to a laser reproduction light control circuit 8 to perform feedback control. The optical output of the semiconductor laser oscillator 1 is kept constant. And the base of the transistor 2 is
A voltage signal output from the laser reproduction light control circuit 8 is input, and at the time of recording, a voltage signal obtained by holding the voltage value input at the time of immediately preceding reproduction by a sample hold circuit or the like is input. The two inputs can be switched depending on whether to record or play. In both recording and reproduction, feedback control is performed based on the optical output level during reproduction.

The transistor 3 is for generating a high intensity laser beam at the time of recording, and a predetermined voltage for recording is transmitted from the recording power reference voltage generating circuit 9 to its base. .. The collector of the transistor 4 is connected to the base of the transistor 3, and the emitter of the transistor 4 is grounded.

A recording pulse signal 44 corresponding to the recording data signal output from the pulse width setting circuit 32 is sent to the base of the transistor 4. The pulse width setting circuit 32 arbitrarily adjusts each pulse width of the recording data signal 38 according to the recording data and outputs it as a recording pulse signal 44. As shown in FIG. 1, a pulse width setting circuit
The reference numeral 32 includes a recording signal output device 33, a triangular wave generator 34, an arbitrary pulse width setting device 35, a reference voltage output device 36, and an AND gate 37.

The operation of the pulse width setting circuit 32 will be described. As shown in FIG. 3, the recording signal output device 33 outputs a recording data signal 38 and a clock 39 synchronized with the recording data signal 38. The recording data signal 38 is output to the AND gate 37, and the clock 39 is output to the triangular wave generator 34. Triangle wave generator 34
For example, the clock 39 is integrated to form a triangular wave 40 and the triangular wave 40 is output to the arbitrary pulse width setter 35. The arbitrary pulse width setting device 35 compares the triangular wave 40 with a reference voltage (DC constant voltage) 41 output from the reference voltage output device 36 and outputs a rectangular wave 42 having a pulse width W.

Further, for example, if the reference voltage output device 36 is DA
In the case of a converter (not shown), the digital signal 43 indicating the type of the optical disc 21 from the control circuit 15 or the digital signal 43 indicating the track address of the optical disc 21 is input to the DA converter, and the reference voltage 41 corresponding to each input is supplied. By outputting from the DA converter, the optical disk 21
A rectangular wave 42 having an optimum pulse width W according to the type of the optical disc or the position of the optical disc in the radial direction is sent to the AND gate 37. Here, the recording data signal 38 is input to one terminal of the AND gate 37 as described above, and the rectangular wave 42 is input to the other terminal. The AND gate 37 has a recording data signal 38.
And the rectangular wave 42 are ANDed, and a recording pulse signal 44 having a pulse width W is output.

The transistor 4 is turned ON / O according to the recording pulse signal 44 output from the pulse width setting circuit 32.
The transistor 3 is turned on / off by being FFed, and the semiconductor laser oscillator 1 is driven by the superimposed signals of the collectors of the transistors 2 and 3 to emit laser light of intermittent high intensity, whereby the optical disc 21 is irradiated. It is designed to record information.

As described above, according to the optical disc apparatus of this embodiment, the pulse width can be arbitrarily set by the single recording width setting circuit 32, and the pulse width can be set according to the type of the optical disc 21 or the position of the optical disc 21 in the radial direction. Recording can be performed with an optimum pulse width, and recording can be surely performed to improve reliability.

[0027]

As described above, according to the present invention, a recording signal output device for outputting a recording data signal and a clock synchronized therewith, a triangular wave generator for generating a triangular wave from the clock, and a direct current serving as a reference. A reference voltage output device that outputs a voltage, an arbitrary pulse width setting device that compares the triangular wave and the reference voltage to arbitrarily set the pulse width, an output signal from the arbitrary pulse width setting device, and the recording signal By providing an AND gate for taking a logical product of the above and outputting a recording pulse and an optical output means for performing recording with the recording pulse, the pulse width can be arbitrarily set by a single recording width setting circuit, and the type of optical disc Alternatively, it is possible to perform fine recording with an optimum pulse width according to the radial position of the optical disc, and it is possible to perform highly reliable recording.

[Brief description of drawings]

FIG. 1 is a block diagram of a pulse width setting circuit in an optical disc device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of the optical disk device.

FIG. 3 is a diagram showing operation waveforms of a pulse width setting circuit in the optical disc device.

FIG. 4 is a configuration diagram of a conventional laser drive unit.

FIG. 5 is a configuration diagram of a conventional pulse width setting circuit.

FIG. 6 is a diagram showing operation waveforms of a conventional pulse width setting circuit.

[Explanation of symbols]

 1 semiconductor laser oscillator 7 photodiode 21 optical disk 22 spindle 24 optical pickup 32 pulse width setting circuit 33 recording signal output device 34 triangular wave generator 35 arbitrary pulse width setting device 36 reference voltage output device 37 AND gate 38 recording data signal 39 clock 40 triangular wave 41 Reference voltage 42 Square wave 43 Digital signal 44 Recording pulse signal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoyuki Suenaga 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Koji Muraoka, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A recording signal output device for outputting a recording data signal and a clock synchronized therewith, a triangular wave generator for generating a triangular wave from the clock, and a reference voltage output device for outputting a reference DC voltage. Outputs a recording pulse by calculating the logical product of an output signal from the arbitrary pulse width setting device and the recording signal, which sets the pulse width arbitrarily by comparing the triangular wave and the reference voltage. AND
An optical disk device comprising a gate and an optical output means for recording with the recording pulse.