JPH04121024U - optical disk device - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose of this invention is to record information at high density while rotating the optical disk 11 at a constant speed. [Structure] The optical disc device of this invention has an optical disc 11
A recording timing signal that changes in proportion to the upper radial position is generated, and pits (information) are formed in synchronization with this signal.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention relates to an optical disc device that records information on an optical disc.

0002

[Conventional technology]

In recent years, image information such as documents, which is generated in large quantities, is photoelectrically converted by two-dimensional optical scanning. Then, this photoelectrically converted image information is stored in an image information storage device, or it is Search, play, and output as hard copy or soft copy as needed. A capable image information storage and retrieval device has been developed. Recently, optical digital devices have been used as image information storage devices in such image information storage and retrieval devices. A disk device is being considered.

0003 This optical disk device uses a two-dimensional scanning device to scan stored documents using a laser beam. create an FM signal by FM modulating the video signal obtained by optical two-dimensional scanning, The laser beam is on-off modulated by this FM signal, and this modulated light is used to rotate the laser beam. The metal coating surface on the optical disk is scanned in a spiral track shape to remove the metal coating surface. The light is melted and deformed according to the modulation content of the modulated light to form a pit row. Image information is recorded as a spiral track-shaped pit row as the disk rotates. do.

0004 Also, when playing back video signals recorded in this way, it is necessary to rotate the optical disc. The recorded track is searched by laser beam light. The reflected light modulated by the pits is detected, and the reflected light is converted into F by photoelectric conversion. Obtain the M signal, demodulate the original video signal, and use this video signal to obtain reproduced image information. It is something that

[0005] However, if the above-mentioned device is used to record information, the contents of the optical disc The linear speed is different between the peripheral part and the outer peripheral part. Therefore, the frequency that maintains the minimum pit distance on the innermost circumference When recording with multiple recording timing signals, the pit spacing increases at the outermost periphery and the recording density increases. The disadvantage is that the value decreases. For example, as shown in Figure 5, the minimum pit interval on the innermost circumference of optical disc 1 is Then, the pit interval L becomes the maximum at the outermost circumference.

[0006] Therefore, as a way to compensate for this drawback, it is possible to keep the recording frequency constant and change the rotation speed. By keeping the linear velocity constant on the inner and outer peripheries, it is possible to maintain a constant linear velocity on all tracks. There are some that record with the minimum pit interval.

[0007] However, in this type of device, the rotation speed of the optical disk is proportional to the radial position. Therefore, we had to change the motor that controls the rotation motor of the optical disk. The motor control circuit is complicated, and it takes time to stabilize the rotation speed. It has the disadvantage of being

[0008]

[Problem that the idea aims to solve]

This idea, as mentioned above, rotates the optical disc at a constant speed while providing high-density recording. This eliminates the disadvantage of not being able to record information on optical discs, and allows optical discs to be recorded at a constant speed. Our aim is to provide an optical disc device that can record information at high density while rotating. target

[0009]

[Means to solve the problem]

The optical disc device of this invention moves the optical disc in the radial direction as it rotates at a constant speed. A linear motor having a movable part that can be moved, fixed to the movable part of this linear motor, A semiconductor laser oscillator that generates laser beam light and the light emitted from this semiconductor laser oscillator. an optical means for guiding the generated laser beam light to the optical disk; An optical system that records information on an optical disc by irradiating the optical disc with beam light. The position of the optical scale fixed to the moving part of the head and the above linear motor is superimposed on the grating. Detection is performed using a shape detection method, and two types of detection with different phases are performed depending on the movement of the movable part. A detection means for outputting a signal, and a detection means that responds to two types of detection signals output by this detection means. This address pulse generating means generates a position pulse when Either up-count or down-count depending on the position pulse from the stage. This address counting means generates a position signal by Conversion means that converts the position signal from the point means into a voltage value; A voltage-controlled oscillator that generates a recording timing signal with a frequency proportional to the applied voltage value. stage, and the above semiconductor according to the recording timing signal from this voltage controlled oscillation means. A control device that controls the output timing of laser beam light generated from a laser oscillator. It is composed of tiers.

0010

[Effect]

This idea is based on the structure described above, in which half of an optical disk rotates at a constant speed. A linear motor that has a movable part that can move in the radial direction, and the movable part of this linear motor A semiconductor laser oscillator that is fixed to and generates a laser beam, and this semiconductor laser and an optical means for guiding the laser beam generated from the oscillator to the optical disk. , information is recorded on the optical disc by irradiating the optical disc with laser beam light. In a device consisting of an optical head for recording, it is fixed to the movable part of the linear motor mentioned above. The position of the optical scale is detected by the overlapping grid detection method, and the Outputs two types of detection signals with different phases according to movement, and outputs two types of detection signals with different phases. Generates a position pulse according to the output signal, and increases according to the generated position pulse Generate a position signal by either counting or down-counting. , this generated position signal is converted into a voltage value, and the voltage value proportional to this converted voltage value is Generates a frequency recording timing signal and responds to the generated recording timing signal. The output timing of the laser beam generated from the semiconductor laser oscillator is It is designed to be controlled.

[0011]

【Example】

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

0012 FIG. 1 schematically shows an optical disc device according to this invention. 11 is optical de 12 is a motor for rotationally driving this optical disk 11, and 13 is for recording and reproducing. It is an optical head. This optical head 13 is composed of a movable part 14 and a fixed part 15. It is fixed to the movable part 14 of the DC linear motor 16 that The optical disc 11 is linearly moved in the radial direction by the motor 16 . 17 is the movable part 14 18 is a detection device for detecting the position of the optical scale 17. These are the movable parts 14 (that is, light Two types of detection signals with different phases are now output when the head 13) moves. ing. 19 performs predetermined signal processing on the output signal of the detector 18. A position signal processing circuit that obtains a position signal; 20 indicates the position from this position signal processing circuit 19; A D/A converter that converts the signal into a voltage value, 21 is proportional to the voltage value from the D/A converter 20 A voltage controlled oscillator 22 generates a signal at a frequency of The recorded information is sequentially synchronized with the output from the voltage controlled oscillator 21, that is, the clock pulse. Output page buffer, 23 is the output from the voltage controlled oscillator 21 and the page buffer an AND circuit that outputs recording pulses in accordance with the recording information sequentially supplied from the driver 22; It is.

[0013] For example, the position signal processing circuit 19 receives signals from the detector 18 that have different phases. an address pulse generation circuit 24 that generates position pulses in response to two types of detection signals; , depending on the pulse from this address pulse generation circuit 24 is composed of an address counter 25 that counts down.

[0014] On the other hand, the optical head 13 fixed to the movable part 14 of the linear motor 16 is shown in FIG. Generates laser beam light for recording or reproducing information, as shown in detail. semiconductor laser oscillator 31, lens system 32, polarization beam splitter 33, 1/4 A wavelength plate 34, an objective lens 35 for converging the beam light onto the optical disk 11, and a convex lens. a photodetector that performs photoelectric conversion upon receiving reflected light from the lens 36 and the optical disk 11; 37 etc. are integrally provided. Output beam from the semiconductor laser oscillator 31 The beam light is divided into two beams, a reproduction beam light and a recording beam light, by a laser driver 38. It can be switched to power. This laser driver 38 is It operates in response to recording pulses from the AND circuit 22.

[0015] Next, the operation in such a configuration will be explained. First, the most Information shall be recorded on the outer periphery. That is, the optical head 13 is connected to the optical disc 1. Correspond to the outermost periphery on 1. At this time, the optical disc 11 rotates at a constant speed. There is. Also, at this time, the address is A signal is output from the pulse generation circuit 24 and the address counter 25 is up-counted. to The count value of this address counter 25, that is, the position signal is sent to the D/A converter 2. This D/A converter 20 converts the position signal into a voltage value and outputs it. this As a result, the voltage controlled oscillator 21 determines the recording timing of the frequency corresponding to the supplied voltage value. Outputs a switching signal. This recording timing signal is supplied to the page buffer 22. , recording information is sequentially output from this page buffer 22 in synchronization with the recording timing signal. Powered. As a result, the AND circuit 23 responds to the recording timing signal and recording information. A recording pulse similar to that is output. This allows the optical head to respond to the recording pulse. 13 to form a pit.

[0016] That is, the output of the AND circuit 23, that is, the recording pulse is supplied to the laser driver 38. Therefore, the laser driver 38 turns on the laser oscillator when the recording pulse is supplied. By switching the output beam light of 31 to the recording beam light, the output beam light becomes Lens system 32, beam splitter 33, 4/1 wavelength 34, and objective lens 35. The recording pulse (recording information) is irradiated onto the optical disc 11 through the optical disc 11. A pit P corresponding to the information) is formed. In this way, the optical diode shown in Figure 3 Pit P is formed at the outermost periphery of the disk 11 with a minimum pit interval.

[0017] From now on, when forming a pit P at another position, that position, that is, the position of the optical disc 11. By outputting a recording timing signal with a frequency according to the radial position, the minimum pitch is Pit P is formed at intervals of .

[0018] In this way, the recording timing changes in proportion to the radial position on the optical disc 11. A signal is generated and pits (information) are formed in synchronization with this signal. , the pits P can be formed at any position on the optical disc 11 with the minimum pit interval. It is something that In addition, as in the conventional case, the rotation of the optical disc 11 for each track position is No need to change the number, which simplifies the motor control circuit and reduces access. You can measure the time savings. Incidentally, a timing chart of main parts for explaining the above operation is shown in FIG.

[0019]

[Effect of the idea]

As detailed above, according to this invention, the optical disk can be rotated at a constant speed while Therefore, it is possible to provide an optical disc device that can record information with high density.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an optical disc device according to an embodiment of the invention.

FIG. 2 is a schematic configuration diagram of the optical head in FIG. 1.

FIG. 3 is a diagram showing a recording example of the optical disc in FIG. 1;

FIG. 4 is a timing chart of main parts for explaining the operation of the optical disc device of FIG. 1;

FIG. 5 is a diagram showing a recording example for explaining a conventional recording method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11... Optical disk, 13... Optical head, 16... DC linear motor, 17... Optical scale, 18... (position) detector, 19... Position signal processing circuit, 20... D/A converter, 21
...Voltage controlled oscillator, 22... Page buffer, 23... AND circuit, 24... Address pulse generation circuit, 25... Address counter, P... Pit.

Claims (1)

[Scope of utility model registration request] 1. A linear motor having a movable part that is movable in the radial direction of an optical disk that rotates at a constant speed, and a semiconductor laser that is fixed to the movable part of the linear motor and generates a laser beam. The semiconductor laser oscillator includes a laser oscillator and an optical means for guiding the laser beam generated from the semiconductor laser oscillator to the optical disk, and records information on the optical disk by irradiating the laser beam onto the optical disk. The positions of the optical head and the optical scale fixed to the movable part of the linear motor are detected by an overlapping grating detection method, and two types of detection signals with different phases are output in accordance with the movement of the movable part. Detection means and 2 outputted by this detection means
An address pulse generating means that generates a position pulse in response to a seed detection signal, and an address counter that generates a position signal by either up-counting or down-counting in response to the position pulse from the address pulse generating means. converting means for converting the position signal from the address counting means into a voltage value; voltage controlled oscillation means for generating a recording timing signal with a frequency proportional to the voltage value converted by the converting means; An optical disc device comprising: control means for controlling the output timing of laser beam light generated from the semiconductor laser oscillator in accordance with a recording timing signal from the oscillation means.