JPH02214036A - Optical disk mastering device - Google Patents

Abstract

PURPOSE:To obtain an optical disk mastering device by which the output level of a laser beam can easily be adjusted with high accuracy and the degree of a modulation can be stabilized by providing a voltage fine adjustment circuit between a voltage conversion circuit and a modulator. CONSTITUTION:The subject device is composed in such a way that the voltage fine adjustment circuit 3 is connected between the voltage conversion circuit 2 and the modulator 5. The circuit 3 sets a signal converted by the circuit 2 at a voltage suitable for the modulation of the laser beam at the modulator 5. Therefore, the modulator 5 modulates the intensity of the laser beam based on the signal from the circuit 3 when an output signal from a formatter 1 is analog data in which a video signal or an audio signal, etc., is converted to a digital signal, and outputs a modulated laser beam. Also, when it is prescribed digital data, the modulator makes the laser beam emit intermittently based on the signal from the circuit 3, and outputs an intermittent laser beam. In such a manner, since the input voltage of the modulator can always be kept constant and the modulation factor can be stabilized, an optical disk can be manufactured with high accuracy.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention adjusts the input signal level to a modulator,
The present invention relates to an optical disc mastering device useful for stabilizing the modulation degree of laser light.

[Prior Art and Problems to be Solved by the Invention] Optical disks are known as highly reliable compact memories that can record data at high density.

With this optical disc, a large amount of documents, maps, melodies, videos, etc. can be recorded. Data on this optical disc is recorded on a substrate in an optically detectable form such as a pit row, and when manufacturing an optical disc, a mastering device is used to create a master disc of the optical disc.

FIG. 2 is a diagram showing a conventional optical disc mastering device. ,.

The above device converts analog input signals such as melody signals, audio signals, video signals, etc. into digital signals, and also includes a formatter (11) for formatting, and a formatter (11) that lowers the digital signals output from the formatter (11) at a fixed ratio. A voltage conversion circuit (12
) and a modulator (14) that modulates the laser light emitted from the argon laser oscillator (13) based on the voltage signal output from the voltage conversion circuit (12). Further, the laser beam modulated by the modulator (14) is reflected by the reflecting mirror (15), and is reflected by the condensing lens (15).
B), the beam is focused and irradiated onto the substrate (17) rotating on a spindle (not shown) while scanning in the radial direction. Note that the substrate (17) is coated with photoresist.

According to the above-mentioned optical disc mastering device, by setting the digital signal output from the formatter (11) to an appropriate level for the modulator (14) using the voltage conversion circuit (12), as shown in FIG. 3(A), ,
The laser beam can be modulated to have an intensity corresponding to the digital signal output from the formatter (11). Therefore, this modulated light is transferred to the substrate (17) coated with photoresist.
By illuminating the top, data from the formatter (11) can be recorded on the substrate.

However, there are various types of modulation methods using the modulator (14), and a single formatter (11)
Therefore, the voltage of the output signal from the formatter (11) varies depending on the manufactured modulation circuit. Therefore, even if the voltage of the output signal from the formatter (11) is converted at a constant ratio by the voltage conversion circuit (12), it is difficult to properly modulate the laser beam by the modulator (14). More specifically, the level of the signal output from the formatter (11) varies depending on the modulation method, for example, the circuit manufactured to realize the MFM modulation method, 2-7 modulation method, PE modulation method, etc. The level of the output signal varies between 4 and 5 volts. Further, since the voltage conversion circuit (12) converts the fluctuating output voltage from the formatter (11) at a constant ratio, the potential of the converted signal also fluctuates in proportion to the output voltage of the formatter (11).

The modulator (14) modulates the laser light to a level proportional to the fluctuating output voltage.
As shown in B), the level of the laser beam is attenuated, which may deteriorate the quality of the master disc or the stamper obtained by nickel plating or the like, or may produce completely defective products.

On the other hand, although it is possible to adjust the voltage levels of the circuits of all modulation methods to be completely the same, this is not practical.

In addition, in order to make the degree of modulation of the laser beam appropriate with the modulator (14), the modulator (■4) is used for each different modulation method.
It is also possible to adjust the intensity of the laser beam by adjusting the internal power supply circuit.

However, since there is a high voltage section inside the modulator (14), adjusting the voltage inside the modulator (14) is not only dangerous but also
), the voltage adjustment work becomes complicated and inefficient.

Regardless of the modulation method, the input voltage to the modulator can be maintained constant even if the output voltage of the formatter fluctuates, and the output level of the laser beam can be easily and precisely adjusted. An object of the present invention is to provide an optical disc mastering device that can stabilize the degree of modulation.

[Means for Solving the Problems] The present invention lowers the potential of a signal output from a formatter at a fixed ratio using a voltage conversion circuit, and modulates laser light using a modulator based on the signal from the voltage conversion circuit to generate a substrate. An optical disk mastering device in which a voltage fine adjustment circuit is connected between the voltage conversion circuit and the modulator to adjust the level of the signal output from the voltage conversion circuit to an appropriate level for the modulator. This solves the above problem.

[Function] According to the present invention having the above configuration, since the voltage fine adjustment circuit is connected between the voltage conversion circuit and the modulator, even if the voltage of the output signal from the formatter fluctuates due to the modulation method, The level of the signal output from the voltage conversion circuit can be adjusted to an appropriate level for the modulator. In addition, the modulator can adjust the laser beam to the appropriate degree of modulation based on the appropriate level signal from the voltage fine adjustment circuit.
The output signal of the formatter can be converted to a level suitable for master disc production.

[Example] The present invention will be described in detail below based on the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of the optical disc mastering device of the present invention. It has a voltage conversion circuit (2) that converts it into a signal.

There is also a voltage fine adjustment circuit (3) that finely adjusts the signal output from the voltage conversion circuit (2) to an appropriate value according to the potential of the signal output from the formatter (1); ) and a modulator (5) that modulates the laser light emitted from the argon laser oscillator (4) based on the signal output from the argon laser oscillator (4). This modulator (5
) is reflected by a reflecting mirror (6), condensed by a condensing lens (7), and irradiated onto a substrate (8) coated with photoresist. Note that the substrate (8) is irradiated while scanning the laser beam in the radial direction.

The above formatter (1) includes a melody signal, an audio signal,
It converts analog input signals such as video signals into digital signals, and sets error correction codes, synchronization signals, etc. to digital data such as documents and maps. Note that the output level of the formatter (1) differs depending on the modulation method, and the level usually fluctuates within a range of 4 to 5 volts. The output potential of the formatter (1) can be measured in advance and used as data for adjusting the voltage to an appropriate voltage in the voltage fine adjustment circuit (3).

The voltage conversion circuit (2) lowers the potential of the digital signal output from the formatter (1) to approximately 1 volt, which is the appropriate level for the circuit in the modulator (5). signal voltage to 115
It is converted to the potential of Therefore, the output potential from the voltage converter circuit (2) usually fluctuates within a range of 0.8 to 1 volt.

A voltage fine adjustment circuit (3) is connected between the voltage conversion circuit (sword) and the modulator (5), and this voltage fine adjustment circuit (3) is converted by the voltage conversion circuit (2). The signal is set to a voltage suitable for modulating the laser light in the modulator (5). In this example, it is set to 1 volt, which is the appropriate level for the circuit in the modulator (5). As the rectifier circuit (3), for example, an input voltage adjustment type that adjusts the signal level supplied to the input terminal of an amplification element such as a transistor or an operational amplifier with a volume control, or an input voltage adjustment type that adjusts the level of the output signal of the amplification element with a volume etc. An example is an output voltage adjustment type.

The modulator (5) uses different modulation methods depending on the content of the data output from the formatter (1).

That is, when the signal output from the formatter (1) is a video signal or an analog signal obtained by converting an audio signal into a digital signal, the voltage fine adjustment circuit (3)
), the intensity of the laser beam is modulated based on the signal from the reflector (6), and the modulated laser beam is reflected by the reflecting mirror (6) and then the condensing lens (7).
irradiate while adjusting the focus and scanning in the radial direction of the substrate (J3). Also, Format Ivy (
If the signal output from 1) is digital data such as documents, maps, etc., formatted with error correction codes, synchronization signals, etc., the laser beam is output based on the signal from the voltage fine adjustment circuit (3). The substrate (8) is irradiated with the intermittent laser light in the same manner as described above.

According to the optical disk mask ring device described above, even if the modulation method is different and the output voltage from the formatter (1) is different, the voltage fine adjustment circuit (3) allows the modulator (5) to
The potential output to the modulator (5) can be adjusted to the most appropriate level for the circuit in the modulator (5), for example 1 volt. That is,
The input voltage to the modulator (5) can be easily and accurately adjusted to an appropriate level. Therefore, there is always a modulator (
The input voltage to 5) can be set to a constant value, the degree of modulation of the laser beam can be stabilized, and optical discs can be manufactured with high precision.

Furthermore, if a voltmeter or scope is connected to the output terminal of the voltage fine adjustment circuit (3), even if the output potential changes during irradiation of the laser beam field, it can be adjusted to an appropriate potential.

In the above example, the manual voltage fine adjustment circuit (3) was explained, but the output voltage of the formatter (1) or the voltage conversion circuit (2) is A/D converted and its potential is calculated.
Automatically amplify or attenuate the output voltage from the voltage conversion circuit (2) based on the calculated voltage and the voltage necessary to appropriately modulate the laser light in the modulator (5), for example, a voltage of 1 volt. An automatic voltage fine adjustment circuit may be used.

[Effects of the Invention] As described above, according to the optical disc mastering device of the present invention, since the voltage fine adjustment circuit is connected between the voltage conversion circuit and the modulator, the formatter can be adjusted regardless of the modulation method. Even if the output voltage of the modulator fluctuates, the input voltage to the modulator can be maintained constant. In addition, the voltage fine adjustment circuit can adjust the level of the signal output from the voltage conversion circuit to the appropriate level of the modulator, so the output level of the laser beam can be adjusted easily and with high precision, and the degree of modulation of the laser beam can be stabilized. be able to. Therefore, optical disc masters can be manufactured with high precision, and deterioration in quality and generation of defective products can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the mastering device of the present invention, FIG. 2 is a block diagram showing a conventional optical disc mastering device, and FIG. 3 (^) is a schematic diagram showing the normal state of laser modulated light.
FIG. 3(B) is a schematic diagram showing a defective modulation state of laser modulated light. (1)...formatsuta, (ri...voltage conversion circuit,
(3)...Voltage fine adjustment circuit, (5)...Modulator patent applicant Daicel Industries Co., Ltd. Agent Patent attorney Hoe 1) Mitsuru Seiko Diagram (B)

Claims (1)

[Claims] In an optical disc mastering device, a voltage conversion circuit lowers the potential of a signal output from a formatter at a fixed ratio, and a modulator modulates laser light based on the signal from the voltage conversion circuit to irradiate the substrate. An optical disc mastering device characterized in that a voltage fine adjustment circuit is connected between the voltage conversion circuit and the voltage fine adjustment circuit for adjusting the level of the signal output from the voltage conversion circuit to an appropriate level for the modulator.