JPH01144266A - Recording disk reproducing device - Google Patents

Abstract

PURPOSE:To surely obtain rotating speed corresponding to the kind of a disk by discriminating the kind of the disk based on difference in the moment of inertia of the disk. CONSTITUTION:A number of revolution detecting means 60 detects the number of revolution of the driving motor 20 of a recording medium 10, and the number of revolution per unit time is measured by a rotating speed measuring means 45, and the acceleration of the driving motor 20 in the neighborhood of a prescribed time is measured. And the kind of the recording medium 10 with different moment of inertia is discriminated based on measured acceleration, and initial rotating speed corresponding to the kind of the recording medium 10 is decided by the rotating speed decision means 35, and the driving motor 20 accelerated or decelerated to the initial rotating speed at a motor control part 30 based on a signal from the rotating speed decision means 35. In such a way, it is possible to obtain the stable discriminated result of the kind of the disk, and to surely obtain the rotating speed corresponding to the kind of the disk.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention automatically determines the difference in diameter of a disk-shaped recording medium (hereinafter abbreviated as disk) such as a video disk, and
The present invention relates to a recording disk reproducing device having a function of providing a rotational speed corresponding to the disk.

2. Description of the Related Art In recent years, it has become important for playback devices for optical video discs, which are one type of video disc, to be able to play optical digital audio discs as well. Among these, one that uses the same motor to play video discs and digital audio discs with different diameters and rotational speeds is advantageous in terms of cost.

An example of the above-mentioned conventional recording disk reproducing apparatus will be described below with reference to the drawings.

FIG. 3 is a block diagram of a conventional recording disk reproducing apparatus. In FIG. 3, 10 is a disk, 20 is a disk 1
This is a drive motor that rotates the o. 6o is a rotation speed detector that outputs a pulse signal according to the rotation of the drive motor 20, and 3o is a motor control unit that drives and controls the drive motor 20. 15 and 18 are reflective photosensors, and if there is no disc, the reflected light will not return to both FoI and sensors 15 and 16, and in the case of a digital audio disc (diameter 121), only the photosensor 15 will receive reflected light. It is reflected on the disk 10 and returns 9, and in the case of a video disk (diameter 20α or 3oα), the photosensors 15, 1
6 are arranged in such a positional relationship that the reflected light is reflected back to the disk 1o. 50 is a disc type determination unit that determines the type of disc based on the output from the reflective photosensor 15, 16; 35 is a disc type determination unit 5;
This is a rotational speed determining means that provides a target initial rotational speed of the drive motor 2o to the motor control unit 3o according to the output of the drive motor 2o. 18 is a top case of the recording disk reproducing device.

The operation of the recording disk reproducing apparatus configured as described above will be explained below.

The actual operation is realized by a microcomputer, and a flowchart thereof is shown in FIG. The disk 1o is mounted on the recording disk reproducing device, and the reflective photosensor 15.
16, information on the diameter of the disc 1° is transmitted to the disc type determination section 60. The disc type determination unit 5o is a fourth
As shown in the figure, a determination is made as to whether there is no disc, a digital audio disc, or a video disc based on the contents of the reflective photosensors 15 and 18, and the rotation speed determination unit 35
Send that information to. The rotation speed determination unit 35 issues a rotation stop command if there is no disc, sets the initial rotation speed to 500 rpm in the case of a digital audio disc, and 1800 rpm in the case of a video disc.
The information is transmitted to the motor control unit 3o. The motor control unit 30 is
While observing the output of the rotation detector 60, the drive motor 2o is accelerated until the set initial rotation speed is reached.

Problems to be Solved by the Invention However, with the above configuration, depending on the sensitivity of the reflective photosensors 15 and 16, the reflective photosensors 15 and 16 may be affected by external light or light reflected on the top case 18, There was a problem in that the sensor caused false detection, incorrectly determined the disk diameter, and caused the disk to rotate at a rotation speed different from the predetermined rotation speed.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above-mentioned problems and to provide a recording disk reproducing apparatus that reliably determines the type of disk and rotates the disk at a rotational speed corresponding to the type of disk.

Means for Solving the Problems In order to solve the above-mentioned problems, the recording disk reproducing apparatus of the present invention includes a drive motor for rotating a disk-shaped recording medium;
A rotation speed detection means of the drive motor, a rotation speed measurement means for measuring the rotation speed based on the output of the rotation speed detection means, and an acceleration of the drive motor based on the output of the rotation speed measurement means before and after a predetermined time. a rotational speed determining means for determining the type of the recording medium based on the moment of inertia from the acceleration measured by the acceleration measuring means, and determining an initial rotational speed according to item 1 of the recording medium; and motor control means for accelerating or decelerating the drive motor to the initial rotation speed based on a signal from the rotation speed determining means.

Operation With the above configuration, since the type of disk is determined based on the difference in the moment of inertia of the disk, a stable disk type discrimination result can be obtained, and a rotational speed corresponding to the disk type can be reliably obtained.

Embodiment Hereinafter, a recording disk reproducing apparatus according to an embodiment of the present invention will be explained with reference to the drawings. FIG. 1 is a block diagram of a recording disk reproducing apparatus according to an embodiment of the present invention.

Note that configurations similar to the conventional one shown in FIG. 3 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

In FIG. 1, 1o is a disk, 20 is a disk 1o
It is a drive motor that rotates the

60 is a rotation speed detector that outputs a pulse signal according to the rotation of the drive motor 20, and 3o is a motor control unit that controls the rotation of the drive motor 2o. 45 is the rotation speed detector 6o
A rotational speed measurement unit 40 measures the rotational speed of the drive motor 2° by counting the number of output pulses per unit time; The acceleration measuring unit 35 determines the type of the video disc, digital audio disc, or disc with a different moment of inertia based on the output of the acceleration measuring unit 4o, and sets the initial rotational speed of the disc accordingly. 3o is the rotational speed determining unit.

Regarding the recording disk reproducing device configured as described above, the first
The operation will be explained using FIG.

In FIG. 1, each means of the rotational speed measuring section 45, acceleration measuring section 46, and rotational speed determining section 35 shown within the frame of the broken line can be easily realized by a microcomputer, and in particular, the acceleration measuring section FIG. 2 shows a flowchart regarding the operations of the rotation speed determination section 4o and the rotation speed determination section 45.

First, the initial rotation speed is set in the motor control unit 3o to 1800 rpm, which is the initial rotation speed of the video disc, and the drive motor 2o is started to rotate.

The rotation speed of the drive motor 200 is monitored by the rotation detector 6o and the rotation speed measuring section 45, and the acceleration measurement start speed ω
. Wait till it becomes. The rotation speed is ω.

If it is, the predetermined time t has arrived. Wait for time t to elapse.

Measure the oral transmission velocity ω after the elapse of time. It is clear that this speed ω corresponds to the acceleration β. The rotation speed ω of the knob is ω=ω. +βto, and therefore the acceleration β is determined by β=(ω−ω.)/lo. These results are transmitted to the rotational speed determining section 35. Due to the difference in the moment of inertia of the disc 10, the rotational speed ω and acceleration β are values unique to each disc, and there is a relationship between ω for a video disc, ω for a digital audio disc, and ω for the case without a disc. Rotation speed determination section 3
A predetermined f axis dividing each at 5 is ω1. ω2
The type of disc is determined by comparing the speed with 1800 rpm in the case of a video disc, 500 rpm in the case of a digital audio disc, and a rotation stop command is set as the initial rotation speed if there is no disc and is transmitted to the motor control unit 3o. The motor control unit 3o accelerates or decelerates the drive motor 2Q until it reaches the set initial rotation speed.

As described above, since the disc type is discriminated based on the difference in the moment of inertia of the disc, a stable disc type discrimination result can be obtained, and a rotational speed corresponding to the disc type can be reliably obtained.

Effects of the Invention As described above, the present invention provides a drive motor for rotating a disc-shaped recording medium, a rotation speed detection means for the drive motor, and a rotation speed measurement method for measuring the output of the rotation speed detection means per unit time. means, an acceleration measuring means for measuring the acceleration of the drive motor based on the output of the rotational speed measuring means before and after a predetermined time, and determining the type of the recording medium having a different moment of inertia from the acceleration measured by the acceleration measuring means. A rotational speed determining means for determining an initial rotational speed according to the type of the recording medium, and a motor control means for accelerating or decelerating the drive motor to the initial rotational speed based on a signal from the rotational speed determining means. According to
It is possible to obtain a stable disc type discrimination result, and to reliably obtain a rotational speed according to the disc type, which has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a recording disc reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a flowchart for explaining the operation of the recording disc reproducing apparatus, and FIG. 3 is a diagram of a conventional recording disc reproducing apparatus. FIG. 4, which is a block diagram showing the configuration, is a flowchart for explaining the operation of the conventional recording disk reproducing apparatus. 1o...disc, 2o...drive motor, 3Q...motor control unit, 35...
...Rotation speed determination section, 4o...Acceleration measurement section,
45...Rotation speed measuring section, 6o...Rotation speed detector. Name of agent: Patent attorney Toshio Nakao and 1 other person/Q
-m-disk true 1 diagram L
J No. 21! ! Figure 3 Figure 4

Claims (1)

[Claims] A drive motor that rotates a disc-shaped recording medium, a rotation speed detection means that detects the rotation speed of the drive motor, a rotation speed measurement means that detects the rotation speed from the output of the rotation speed detection means, and an acceleration measuring means for measuring the acceleration of the drive motor based on the output of the rotational speed measuring means; and determining the type of the recording medium having a different moment of inertia from the acceleration measured by the acceleration measuring means, depending on the type of the recording medium. A recording disk characterized in that it comprises a rotational speed determining means for determining an initial rotational speed, and a motor control means for accelerating or decelerating the drive motor to the initial rotational speed based on an output signal from the rotational speed determining means. playback device.