JPS6334768A - Disk size detector - Google Patents

Abstract

PURPOSE:To detect the size, kind, etc., of a disk within a short period by impressing a prescribed voltage to a disk motor for a prescribed time to idle the motor before reproducing a disk recording information, detecting the rotational frequency of arrival and comparing the detected value with a previously fixed reference rotational frequency. CONSTITUTION:A disk motor driving instruction signal forming circuit 1 generates a disk motor driving instruction signal for a prescribed period after the generation of a disk loading signal, and when a disk motor driving circuit 2 impresses the prescribed voltage to be disk motor for the prescribed period, a rotational frequency detector 4 is driven interlocking with the disk motor 3 to generate pulses proportional to the rotational frequency. On the other hand, a gate pulse generating circuit 6 generates a gate signal for a prescribed period with a slight delay. A rotational frequency comparator 7 counts up the outputs of the detector 4 only when the gate pulses are generated by the circuit 6, compares the counted value with a previously set up reference value and generates a low level signal when the number of pulses is small or generates a high level signal when the number of pulses is large to decide the disk size by its output through a latch circuit 7.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention detects the disc size or disc type of a loaded disc in a video disc player or a dual-purpose player that can play both a compact disc and a video disc in the same player. Regarding a detection device.

[Conventional technology]

A conventional device for detecting disk size, etc. is disclosed in Japanese Patent Application Laid-Open No. 57
- As shown in Publication No. 210480, during a sequence in which a motor that drives and rotates a disk is started and a playback signal is obtained, the time taken for the rotation speed of the motor to reach the reference rotation speed is compared with the reference time. is known, but this does not take into account the fact that discs with different recording formats may be played back by the same player.

Alternatively, a method is used in which the disc size is detected by arranging equal parts of the optical sensors at appropriate positions and detecting the difference in the amount of light incident on the optical sensor depending on whether the disc surface reaches the optical sensor placement position or not. It is being In such a detection method, since it is necessary to newly provide an optical sensor, there is a problem in that the cost increases.

[The problem that the problem is trying to solve]

The above-mentioned conventional technology does not take into consideration the problems that occur when determining the disc size or type of a dual-purpose player that can play discs on which information is recorded in completely different formats, such as compact discs and laser discs.

In the case of a dual-purpose player such as ``-2'', it is possible to use both the optical pickup and disc motor, but due to differences in the recording format and disc weight, it may be difficult to switch the signal processing circuit, software for the system control section, or servo drive. If you do not switch the circuit before starting playback of the disc, not only will you not be able to obtain a proper JC playback signal,
This may lead to the system going out of control. The above-mentioned conventional technology has the above-mentioned problem because it is configured to perform disc determination in the sequence up to disc startup and playback.

Also, how to determine the disk size and type in advance and 1-
Although it is possible to use an optical sensor or the like as in the above-mentioned prior art, it is necessary to additionally provide an optical sensor or the like to determine the disc size and type.

There was a problem in that it led to an increase in costs.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a detection device that detects the disk size, type, etc. in a short time before a disk motor start-up playback sequence in an inexpensive manner without adding a new device to the current system. It is in.

[Means for solving problems]

The above problem occurs after the disc is loaded or after a sequence in which the disc may be loaded (for example, in a type of player that front loads the disc, the transport table for loading the disc is pushed in and holds the disc down). (Immediately after the clamp mechanism that attaches the disc is activated), before starting the disc motor and playing back the recorded information on the disc, by applying a predetermined voltage to the disc motor for a predetermined period of time, only the disc motor is allowed to idle, and the number of revolutions reached is determined. This can be achieved by detecting the rotation speed and comparing it with a predetermined standard rotation speed. In other words, by utilizing the fact that the moment of inertia of a disk is proportional to the square of the radius and the mass of the disk, and that the number of rotations reached when a specified voltage is applied to the disk motor for a specified period of time differs depending on the difference in the moment of inertia, the above objective can be achieved. This is to solve the problem.

[Effect]

In the above sequence, the disk motor drive circuit:
It operates so that a predetermined voltage is applied to the disc motor for a predetermined period of time. This causes the motor to rotate an instantaneous amount. The number of rotations reached varies depending on the moment of inertia of the disk. As mentioned above, the disc inertia moment differs depending on the disc size or type, so by detecting the reached rotation speed using a rotation speed detection means and comparing the detected force with a preset reference rotation speed. Disc size and type can be detected before recording information is played back.

〔Example〕

The present invention will now be described in detail with reference to the drawings.

The figure is a block diagram showing one embodiment of the present invention.

In the figure, 1 is a disk motor drive command signal generation circuit, 2 is a disk motor drive circuit, 3 is a disk motor, 4 is a rotation speed detection device, 5 is a waveform shaping circuit, 6 is a gate pulse generation circuit, and 7 is a rotation speed. The comparison circuit 8 is a latch.

Next, the circuit operation will be explained.

In the figure, the disk motor drive command signal generation circuit 1 is as follows:
A disk motor drive command signal is generated for a predetermined period of time after the disk loading signal is generated (occurs when a disk is loaded or when there is a device possibility). The disk motor drive circuit 2 is adapted to apply a predetermined voltage to the disk motor 3 for the predetermined period of time in response to the disk motor drive command signal.

The rotation speed detection device 4 is attached to move in conjunction with the disk motor 3, and is configured to generate pulses proportional to the rotation speed of the disk motor 5. There are some that use a frequency generator (frequency generator), a photointerrupter, etc.

The gate pulse generating circuit 6 receives a disk motor drive command signal and generates a gate signal for a predetermined period of time with some delay from the generation of the white signal only when it is necessary to determine the disk size or type. The rotation speed comparison circuit 7 is composed of a pulse counter, and only when a gate pulse is generated in the gate pulse generation circuit 6, the rotation speed detection device f
! The output of i is counted as the number of pulses input via the waveform shaping circuit 5. The current count pulse number is compared with the reference number set (1i') a, and if the counted pulse number is smaller than the set reference number, it is a low level, for example.

When the number of pulses is higher than the set standard number, a high level is generated (,
12, the output of the rotation speed comparison circuit 7. This output is sent to the latch circuit 7 and latched. This latch output allows the disk size to be kept constant.

The /chi output is latched until the 5th disk loading signal' is generated.4 In this embodiment, if the setting reference number is set according to the assumed disk size or type, the disk Since the number of revolutions reached by the motor differs depending on the disc size and type, the disc size or type can be detected instantaneously before the recorder a-information reproduction sequence. .

It is obvious that if a large number of diffuser types are expected, a large number of set reference numbers should be prepared in the rotational speed comparator circuit 7 and two output bits should be increased.

Also, it is possible that the disk is not installed when the disk size is determined to be small, but this problem
It will be resolved in a later sequence. As for the case, it is obvious that the setting reference number to be used for determining the presence of a disk and the presence of a disk using the same method as described above can be newly provided in the rotation speed comparison circuit 7.Q,E).

Alternatively, the rotation speed comparison circuit 7 may be formed by converting the output of the rotation speed detection device 4 into an analog signal and using an analog comparator or the like.

Not only the disk motor 5 shown in this embodiment but also the rotation speed detection device 4 are already provided in the video disk drive for other purposes, and other rotation speed comparison circuits and the like are installed in the video disk drive. This can be done by using a micro, combination, etc. that is already installed in the 1'-ya.
)・-de-like 1. This has the effect of being able to detect the disc size or type without the need for X+.

Effects of the Invention] According to the present invention (C), it is possible to add new components to a video disc player, etc., without adding any new components such as
This method has the advantage of being able to detect and determine the day 7, size, or type almost simultaneously with the loading of the disc using an inexpensive method, and smoothly proceeding to the recorded information reproduction sequence.

In addition, after the disk device and before the recorded information playback sequence, K 7
” In order to make a risk judgment, we need to obtain recorded information.
Although there is a concern that the time will be delayed, the predetermined time for idling the disk motor is sufficient on the order of several hundred 7+@(8), and its effect on the entire sequence is extremely small.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention. . 1...Disc motor drive command signal generation circuit...Disc motor 4.
......Rotation speed detection device 7...
−・Rotation speed comparison circuit ・−゛agent
Masu Tapping + Masaru Ogawa/Otoko j Figure 4 lT'-1-lI°+shi: z%q-1'D5&δ
, I

Claims (1)

[Claims] 1. A disk size detection device for detecting the disk size of a disk rotationally driven by a motor, comprising means for applying a predetermined voltage to the motor for a predetermined period of time to drive the motor, and a means for driving the motor after driving. It is characterized by comprising means for detecting the reached rotational speed, means for comparing the detected reached rotational speed with a predetermined reference value, and means for determining the size of the disk from the comparison result. Disk size detection device.