JPS59112464A - Revolving speed control device of optical recording device - Google Patents

Abstract

PURPOSE:To detect a revolving speed of an information recording disk and to control exactly the revolving speed by providing slit parts by equal intervals extending over the whole circumference, on a part of the information recording disk, and detecting this slit by a noncontact system. CONSTITUTION:A slit part 52 provided on an information recording disk 50 is constituted by providing a part for making a light transmit and a nontransmitting part (reflecting part) to each other at equal intervals, and the number of slits constituted in one rotation of the disk 50 is supplied to a revolving speed controlling circuit part 30 from a photodetector 22, amplified by an amplifier 31, and also inputted as a pulse signal to a comparing circuit 34 through a differentiating circuit 32 and a monostable multivibrator 33. Said signal is compared with a reference signal from a reference signal generator 35 in said circuit, and a rotating motor 3 is driven so that its difference becomes zero. In this way, the revolving speed of the information recording disk 50 is controlled exactly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a rotation speed control device for an optical recording device, and more particularly to a rotation speed control method for accurately controlling the rotation speed of an information recording disk.

(Prior Art) Conventionally, a rotary drive section that holds an information recording disk and rotates at high speed, a pickup section that records an information signal on the information recording disk by using a light beam with unevenness or shading, and a pickup section that is connected to the information recording disk. In an optical recording device equipped with a drive section for operating in a radial direction, a light beam irradiated from a pickup section onto a predetermined recording section of the information recording disk is used to record information signals in a spiral or concentric pattern with irregularities, shading, etc. In order to record information, it is necessary to accurately control the rotational speed of the information recording disk.If not, the information signal recording section may overlap, resulting in a defective reproduced image, or the reproduced image may be distorted due to recording unevenness. Generally, to control the rotational speed of an information recording disk, a frequency generator (PG) and a DC voltage generator are used in a rotary motor, which is a rotation drive unit for rotating the information recording disk at high speed. (DG) etc., the rotation speed of the rotary motor is controlled by obtaining an output signal proportional to the rotation speed of the rotary motor, and the rotation speed of the information recording disk is controlled.

However, although this control method can accurately control the rotational speed of the rotary motor, since the information recording disk is controlled via the information recording disk holder provided in the rotary motor, the holder and the information recording disk cannot be connected to each other. If there is slight vibration due to slipping or rattling during this period, the number of rotations of the information recording disk is not equivalent to that of the rotary motor, and there is a problem that the number of rotations of the information recording disk cannot be accurately controlled.

Further, since a frequency generator (FG) that generates about 500 accurate pulses per revolution is expensive, it has been difficult to use a horizontal synchronization signal as an input signal directly as a reference signal.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a rotational speed control system for an optical recording device that can accurately control the rotational speed of an information recording disk.

[Summary of the invention]

The present invention controls the rotational speed of the information recording disk by controlling the rotational motor by comparing an output signal obtained by the rotational speed of the information recording disk with a reference signal corresponding to a predetermined rotational speed. The present invention is characterized in that slits are provided in a part of the information recording disk at equal intervals over the entire circumference, and by detecting the slits in a non-contact manner, the rotational speed of the information recording disk is detected and the rotational speed is controlled.

[Embodiments of the invention]

FIG. 1 is a system block diagram showing an embodiment of a rotation speed control device for an optical recording apparatus according to the present invention.

FIG. 2 is a perspective view of the configuration of the rotation speed detecting section in FIG. 1.

In the figure, reference numeral 1 denotes a rotary saw 1 which is composed of a holding part 2 of the information recording disk 5o and a rotary motor 6 that rotates the information recording disk 5o at high speed via the holding part 2; 6. An arm movable in the radial direction of the information recording disk 50 by the moving part 10 via the guide part 5; 20 is a holder that holds the light irradiator 21 and the photodetector 22; 30 is an amplification device 31.
Differential circuit 32. Monomulti 33. a rotation speed control circuit section composed of a comparison circuit 34 and a reference signal generator 35;
Reference numeral 51 indicates a recording section of the information recording disk 50, and 52 indicates a slit section that is arranged at equal intervals over the entire circumference of a portion of the information recording disk 50 other than the recording section 51.

Next, the operation of the embodiment will be explained.

The information recording disk 50 is held by a holding section 21C and rotated at high speed by a rotation drive section 1 constituted by a rotation motor 3. Information signals are recorded by irradiating a beam. Furthermore, since the pickup section 4 is held by the arm A which can be moved via the guide section 5 by the operation of the arm drive section 10, it moves in the radial direction of the information recording disk 50 and records a predetermined record on the recording section. 51 to be recorded within 4.

can.

Here, the information recording disk 500 rotation speed control is performed as follows.

The number of slits formed in one rotation of the information recording disk 50 is input to the photodetector 22, that is, the slit configuration of the slit portion 52 provided in the information recording disk 50 is such that light is emitted from each other at equal intervals. Since it is composed of a transmitting part and a non-transparent part (reflecting part), by irradiating the slit part 52 with light using the light irradiator 21 (e.g., a light emitting diode), the part that transmits light can be used for photodetection. Light is incident on the detector 22, and since the light is reflected at the non-transparent portion, the photodetector obtains a substantially sine wave detection signal.

Therefore, the detection signal of the photodetector 22 is transmitted to the rotation speed control circuit section 3.
0, it is amplified by the amplifier 31 of the rotation speed control circuit 30, and is further amplified by the differential circuit 32 and the monomulti 33.
The pulse signal is formed into a pulse signal and is input to the comparator circuit 34. Therefore, in the reference signal generator 35, the predetermined rotational speed of the information recording disk 50 (for example, 1800 and 3600 rotations per minute, etc.) and the slit portion 5 of the information recording disk 50 are determined.
A reference signal obtained from a number of slits of 2 (for example, assuming that the information recording disk 50 rotates at 1800 revolutions per minute, the number of slits is 52)
If there are 5, 15.75KHz, 1 pulse 65.
5ttsec), input it to the comparison circuit 34 in the same way, and compare it with the detection signal from the slit section 52 of the information recording disk 50. The rotary motor 3 is driven so that the difference becomes zero, and the information recording disk 50 The rotation speed of the engine is precisely controlled.

Here, the configuration of the slit section 52 of the information recording disk 50 is equivalent to 525 horizontal synchronizing signals in the case of an information signal, for example, an NTSC television signal (however, in the case of recording one frame per rotation), The rotation speed can be controlled with the accuracy of the horizontal synchronization signal of the recorded video signal, and by inputting the horizontal synchronization signal to the reference signal generator 35 and using it as a reference signal, there is no need for a new circuit system to form a reference signal. become.

In this embodiment, the transmitted light is detected, but the same rotational speed control is also possible by detecting the reflected light from the slit portion 52.

〔Effect of the invention〕

As described above, in the rotational speed control device for an optical recording device according to the present invention, one part of the information recording disk is provided with slits at equal intervals around the entire circumference, and a rotational speed detection means using the slits and a non-contact method is provided. By detecting the rotational speed of the information recording disk and comparing it with a reference signal for a predetermined rotational speed of the information recording disk and controlling the rotating motor, it is possible to always accurately control the information recording disk to a predetermined rotational speed. Conventionally, the rotary motor was accurately controlled by controlling the rotation speed of the rotary motor, but the information recording disk, which is held in the holder of the rotary motor and rotates, may slip or play slightly with the holder. It is possible to solve defects in information signal recording caused by uncontrollability of uneven rotation of the information recording disk caused by vibrations, and to provide an optical recording device capable of good information recording.

[Brief explanation of the drawing]

FIG. 1 is a system block diagram showing a rotation speed control device for an optical recording apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view of the configuration of a rotation speed detection section in FIG. 1. 21... Light irradiator, 22... Photodetector, 52... Slit section, 60... Rotation speed control circuit section, 1... Rotation drive section, 50... Rotation recording disk. , 8. Figure 1 Figure 2

Claims (1)

[Claims] A rotary drive unit that holds an information recording disk and rotates at high speed; a pickup unit that records unevenness or shading on the information recording disk with a light beam; and a drive unit that moves the pickup unit in the radial direction of the information recording disk. an optical recording device comprising: slits arranged at equal intervals over the entire circumference in a part of the information recording disk; a light irradiator that irradiates the slits with light; a photodetector that receives reflected light or transmitted light; a detection signal from the photodetector is compared with a reference signal for a predetermined rotational speed of the information recording disk, and the information recording disk is set at a predetermined rotational speed. 1. A rotation speed control device for an optical recording device, characterized in that the device controls a rotational drive unit as much as possible.