JPH02210670A - Optical disk device - Google Patents

Abstract

PURPOSE:To allow recording while rotating the optical disk at a specified speed without lowering the recording density by generating the recording timing signal of the frequency proportional to the radial position on the optical disk and recording information in synchronization with the timing signal. CONSTITUTION:An optical disk 13 is disposed to face the outermost peripheral part on the optical disk 11 and the disk 11 is rotated at the specified speed in the case of recording the information in the outermost peripheral part on the disk 11. A position signal is outputted from a position detector 18 at this time and is converted by a D/A converter 20 to a voltage value. The recording timing signal of the frequency corresponding to this voltage value is outputted from a voltage control oscillator 21. The recording pulses corresponding to this recording timing signal are outputted from an AND circuit 23 and the pits P corresponding to the recording information are formed at the min. pit intervals l on the disk 11. The recording timing signal of the frequency corresponding to the position where the recording is executed is thereafter outputted in the case of recording the information in other position, by which the pits P are formed at the min. pit intervals l.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical disc device for recording information on an optical disc.

In recent years, image information such as documents, which is generated in large quantities, is charged and converted by two-dimensional optical scanning, and this charged and converted image information is stored in an image information storage device, or it can be searched and reproduced as needed. Image information storage and retrieval devices have been developed that can reproduce and output images as hard copies or soft copies. Optical disk devices have recently been considered as image information storage devices for such image information storage and retrieval devices.

This optical disk device generates an FM signal by FM modulating a video signal obtained by optically scanning a document to be stored using a two-dimensional scanning device using a laser beam.
The laser beam light is on-off modulated by the M signal, and the metal coating surface on the rotating optical disk is scanned in a spiral track shape with this modulated light, so that the metal coating is melted and deformed according to the modulation content of the modulated light. By forming a bit string using the optical disk, image information is recorded as a pit string in the form of a spiral track as the optical disk rotates. In addition, when reproducing a video signal recorded in this way, the optical disk is rotated and the recording track is searched with a laser beam light to detect the reflected light modulated by the pits of the recording track, and the reflected light is detected. The original video signal is demodulated by obtaining an FM signal through photoelectric conversion, and reproduced image information is obtained from this video signal.

Therefore, when information is recorded using the above-mentioned apparatus, the linear velocity differs between the inner circumference and the outer circumference of the optical disc. For this reason, if recording is performed using a recording timing signal having a frequency that maintains the minimum bit interval at the innermost circumference, there is a drawback that the bit interval increases at the outermost circumference and the recording density decreases. For example, if the bit interval g is the minimum at the innermost circumference of the optical disc 1 as shown in FIG. 1, the bit interval will be the maximum at the outermost circumference. Therefore, as a way to compensate for these drawbacks, by keeping the recording frequency constant and changing the rotation speed, the linear velocity at the inner and outer circumferences is kept constant and all tracks are recorded at the minimum bit interval. There is something. However, in this type of device, the number of rotations of the optical disk had to be changed in proportion to the radial position, so the motor control circuit that controlled the motor for rotating the optical disk was complicated, and the number of rotations The disadvantage is that it takes time for the value to become constant.

Therefore, there are disadvantages in that information cannot be recorded while rotating the optical disk at a constant speed without reducing the recording density, and access takes time.

This invention was made in view of the above circumstances, and its purpose is to record information while rotating an optical disc at a constant speed and without reducing the recording density.
Another object of the present invention is to provide an optical disc device that can reduce access speed.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 schematically shows an optical disc device according to the present invention. 11 is an optical disk, 12 is a motor for rotating the optical disk 1.1, and 13 is an optical head for recording and reproducing. The optical head 13 is fixed to a movable part 14 of a DC linear motor 16 that includes a movable part 14 and a fixed part 15, and is thereby linearly moved in the radial direction of the optical disc 11 by the linear motor 16. 17 is an optical scale fixed to the movable part 14, and 18 is a detector for detecting the position of the optical scale 17. These detect the movement of the movable part 14 (that is, the optical head 13) using a so-called overlapping grating detection method. 21i type detection signals with different phases are output. 19 is a position signal processing circuit that obtains a position signal by performing predetermined signal processing on the output signal of the detector 18, and 20 is a D/D converter that converts the position signal from this position signal processing circuit 19 into a voltage value.
A converter 21 is a voltage controlled oscillator that generates a signal with a frequency proportional to the voltage value from the D converter 20, that is, a recording timing signal, and 22 is an output from the voltage controlled oscillator 21, which generates recording information in synchronization with a clock pulse. The page buffer 23 is an AND circuit that outputs a recording pulse according to the output from the voltage controlled oscillator 21 and the recording information sequentially supplied from the page buffer 22.

The position signal processing circuit 19 includes, for example, the detector 18
It consists of an address pulse generation circuit 24 that generates position pulses in response to two types of detection signals with different phases from the address pulse generation circuit 24, and an address counter 25 that counts up or down in response to the pulses from the address pulse generation circuit 24. has been done.

On the other hand, as shown in detail in FIG. 3, the optical head 13 fixed to the movable part 14 of the linear motor 16 includes a semiconductor laser oscillator 31 that generates a laser beam for recording or reproducing information, and a lens. system 32, a polarizing beam splitter 33, a wavelength plate 34, an objective lens 35 for converging the beam light onto the optical disk 11, a convex lens 36, and a photodetector 37 for receiving reflected light from the optical disk 11 and performing photoelectric conversion, etc. It is fully equipped. The output beam from the semiconductor laser oscillator 31 can be switched by a laser driver 38 into two beam powers: a reproduction beam and a recording beam. This laser driver 38 operates in response to a recording pulse from the AND circuit 22 during recording.

Next, the operation in such a configuration will be explained.

First, it is assumed that information is recorded on the outermost circumferential portion of the optical disc 11. That is, the optical head 13 is connected to the optical disk 11.
Correspond to the outermost part on the top. At this time, the optical disc 11
is rotating at a constant speed.

Further, at this time, a signal is output from the address pulse generation circuit 24 based on the detection signal having a different phase from the detector 18, and the address counter 25 is incremented. The count value of this address counter 25, that is, the position signal is D
The position signal is output to the converter 20, and the position signal is converted to a voltage value by the converter 20 and output. Thereby, the voltage controlled oscillator 21 outputs a recording timing signal with a frequency corresponding to the supplied voltage value. This recording timing signal is supplied to the page buffer 22, and this page buffer 22
Recording information synchronized with the recording timing signal is sequentially output. As a result, the AND circuit 23 outputs a recording pulse according to the recording timing signal and recording information. As a result, bits are formed by the optical head 13 in accordance with the recording pulse.

That is, the output of the AND circuit 23, that is, the recording pulse is supplied to the laser driver 38, and therefore the laser driver 3
8, when a recording pulse is supplied, the output beam of the laser oscillator 31 is irradiated onto the optical disk 11 via the recording beam and the objective lens 35, and a pit P corresponding to the recording pulse (recorded information) is formed on the optical disk 11. form. In this way, as shown in FIG.
A pit) P is formed at the outermost periphery of the pit with a minimum pit interval g.

Thereafter, when pits P are to be formed at other positions, a recording timing signal having a frequency corresponding to the position, that is, the radial position of the optical disc 11 is output, so that the pits P are formed at the minimum pit interval g.

In this way, a recording timing signal that changes in proportion to the radial position on the optical disk 11 is generated, and pits are formed in synchronization with this signal.
Pit P can be formed at any position on 1 with the minimum pit interval p.

In addition, as in the past, one optical disc is used for each track position.
Since there is no need to change the number of revolutions of the motor, the motor control circuit becomes simple and the access time can be shortened.

Incidentally, a timing chart of the main parts for explaining the above operation is shown in FIG.

As detailed above, according to the present invention, a recording timing signal with a frequency proportional to the radial position on the optical disk is generated, and information is recorded in synchronization with this timing signal, thereby reducing the recording density. It becomes possible to record information at high density without any problems. In addition, the light source necessary for recording information,
The optical head, which is integrally equipped with focusing means and detection means, is attached to the moving part of the linear motor, and the optical disk is rotated at a constant speed, allowing high-speed access to the target position and recording information quickly. can be done.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a recording example for explaining a conventional recording method, FIGS. 2 to 5 are for explaining an embodiment of the present invention, and FIG. 2 is a diagram showing a schematic configuration of an optical disc device. figure,
FIG. 3 is a schematic and structural diagram of the optical head, FIG. 4 is a diagram showing a recording example, and FIG. 5 is a timing chart of main parts for explaining the operation. DESCRIPTION OF SYMBOLS 11... Optical disk (disc) 13... Optical head, 16... DC linear motor, 17... Optical scale, 18... (position) detector, 19... Position signal processing circuit, 20 ...D converter, 21...voltage controlled oscillator, ...peinhahuaat circuit, 24...address pulse generation circuit, 5...address counter, P...pit◎

Claims (1)

[Scope of Claims] A linear motor having a movable part that is movable in the radial direction of an optical disk that rotates at a constant speed, a semiconductor laser oscillator that is fixed to the movable part of the linear motor and generates a laser beam, and this semiconductor laser. an optical means for guiding a laser beam generated from an oscillator to the optical disk,
an optical head that records information by irradiating the optical disc with a laser beam; and an optical head that detects the irradiation position of the laser beam irradiating the optical disc based on the position of a movable part of the linear motor. position detecting means; output means for outputting a recording timing signal having a frequency proportional to the radial position detected by the position detecting means; An optical disc device comprising: a control means for controlling the output timing of a laser beam;