JPH01298572A - Information reproducing device - Google Patents

Abstract

PURPOSE:To stably decide the sort of a disk without using a reflection type sensor by deciding the sort or existence of an information disk from the number of pulses outputted from a frequency generator during a period from the start of a spindle motor to its acceleration up to a fixed speed. CONSTITUTION:A disk mounting shaft 1 mounting a disk 2 is rotated by a spindle motor constituted of a bearing 3, a magnet 4 and a driving coil 5. The magnet 4 and the coil 6 constitute the frequency generator of the spindle motor, and when the spindle motor is driven by a motor driving means 7 from its stop state up to a certain rotational frequency V, a speed deciding means 8 detects that the period of pulses outputted from the frequency generator reaches the fixed rotational speed and the value of a counter 9 at that time goes a value corresponding to the inertial moment of the mounted disk, so that the sort of the disk can be decided. Thus, the sort of the disk can be stably decided.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an information reproducing apparatus for reproducing various types of information discs.

Conventional technology For optical video discs, the outer diameter is 30 cm.

There are two types of discs: 20C11. As an optical video disc player, in addition to the above-mentioned two types of discs, players that can also play compact discs and CDVs with a diameter of 12 cm have been commercialized. In such a player, it is necessary to detect which disk is loaded in order to change the internal operation mode or change the gain of various control systems depending on each disk. For this reason, in these conventional players, 6
A reflective sensor was installed in each digit of cm to 10ct and 10c+* to 15C1 to determine the type or presence of a disc. (For example, if the TV Technology 8 Hayabusa was dirty, there was a risk of erroneous detection. Also, there were mechanical restrictions due to the installation of a reflective sensor.To solve this problem, , Japanese Patent Publication No. 57-2104
No. 80 discloses means for determining the type of disk by measuring the time until a predetermined rotational speed is reached. This method detects by measuring the start-up time that the start-up speed of the motor differs depending on the difference in the moment of inertia due to the difference in the diameter of the disk.

However, in reality, when the motor starts rotating, there is non-linearity such as static friction force of the bearing and cogging of the motor, so the start-up speed becomes uneven and accuracy cannot be improved.

Problems to be Solved by the Invention In the above example, there are problems such as erroneous detection when the disk is dirty, erroneous detection that occurs because detection accuracy is not improved due to mechanical constraints, or nonlinearity at the beginning of rotation. There was 0
In view of the above-mentioned points, the present invention provides an information reproducing apparatus that does not require a reflective sensor and can stably discriminate the type of disc.

Solve problems. 1 arbitrarily selected from multiple types of means with different diameters or weights.
comprising a spindle motor that rotates a plurality of information disks, and a frequency generator fixed to the rotating shaft of the spindle motor,
The type or presence or absence of the information disk is determined from the number of pulses of the output of the frequency generator while the spindle motor accelerates to a constant speed. Also, when the output of the frequency generator reaches a predetermined number of pulses,
The type or presence or absence of the information disk may be determined from the rotational speed of the spindle motor.

Function The present invention detects the rising speed of rotation based on the actual rotation angle with the above-described configuration, and is therefore less susceptible to non-linear variations at the start of rotation.

Embodiment Hereinafter, an information reproducing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a disc discriminating section of an optical video disc player to which the present invention is applied.

The disc mounting shaft l with the disc 2 mounted thereon has a bearing 3,
It can be rotated by a spindle motor constituted by a magnet 4 and a drive coil 5.

When the coil 6 detects a change in the magnetic flux from the magnetic pole magnetized on the outer periphery of the magnet 4, the output thereof generates a pulse whose period changes depending on the rotation speed of the spindle motor. That is, the magnet 4 and the coil 6 constitute a frequency generator of the spindle motor. Here, when the spindle motor is driven by the motor drive means 7 from a stopped state until it reaches a certain rotation speed V, the number of pulses output from the frequency generator during that time is determined by the number of teeth of the frequency generator being z, and the number of pulses being driven. Torque T1 When the moment of inertia of the rotor of the spindle motor and the disk mounting shaft is Jm, the moment of inertia of the mounted disk is Jd, and the proportionality constant is K, it can be expressed approximately as Kl (Jd+Jm)*Z*V2/T. Therefore, if the speed determining means 8 detects that the pulse period of the frequency generator output reaches a constant rotational speed and the value of the counter 9 at that time is read, it will be determined that the value corresponds to the moment of inertia of the installed disk. It is possible to determine the type of disc. FIG. 2 is a block diagram showing another embodiment of the invention. In this example, contrary to the previous example, the configuration is such that the value of the speed detection means 8 is read when the counter 9 that counts the pulses of the output of the frequency generator reaches a predetermined value. The value corresponds to the moment of inertia, and it is possible to determine the type of disk.In examples of 0 or more, the number of pulses of the output of the frequency generator, that is, the relationship between the rotation angle and speed of the motor that actually rotated. Since the moment of inertia of the disk is detected by using the system, as shown in Figure 3, even when the start-up characteristics are disturbed or delayed due to frictional force of the bearing, cogging of the motor, etc. Unlike when measuring time, there is no large error and stable disk discrimination can be performed. The speed determining means 8 may measure the cycle using a microcomputer, for example, or may use another means. It is clear that the frequency generator and spindle motor may be configured in other ways. .

Effects of the Invention As described above, the present invention has a simple configuration, has no mechanical limitations, and can also provide stable disk discrimination without false detection even when the disk is dirty or the start-up characteristics are disturbed at the start of rotation. You can get the effect that you can.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a disc discriminating section of an optical video disc player which is an embodiment of the present invention, Fig. 2 is a block diagram showing another embodiment, and Fig. 3 is a characteristic showing the start-up characteristics of the motor. It is a diagram. 4...Magnet, 6...Coil, 8
... Speed detection means, 9... Counter. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1

Claims (2)

[Claims] (1) The spindle motor is equipped with a spindle motor that rotates one information disc arbitrarily selected from a plurality of types having different diameters or weights, and a frequency generator fixed to the rotating shaft of the spindle motor. An information reproducing device characterized in that the type or presence or absence of the information disc is determined from the number of pulses of the output of the frequency generator while the information disc accelerates to a constant speed. (2) A spindle motor that rotates one information disk arbitrarily selected from a plurality of types having different diameters or weights, and a frequency generator fixed to the rotating shaft of the spindle motor, and the frequency generator An information reproducing device characterized in that the type or presence or absence of the information disc is determined from the rotational speed of the spindle motor when the output of the machine reaches a predetermined number of pulses.