JPS6341601Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an information recording disk configured to record video information or the like in a concentric circle or a spiral shape and to reproduce it while rotating.

In recent years, video discs and recording/playback devices for them have been developed. This type of device can be roughly divided into two methods: one is a method in which the recorded information engraved on a disk track is reproduced as a change in capacitance using a capacitance detector, and the other is a method in which a laser beam is traced on the disk recorded information to obtain information on the reflected or transmitted light. There are two ways to optically detect the signal.

The current method of the latter is that when recording from the inner circumference, the disk rotation speed is set to 1800 revolutions per minute when using the Japanese and American television standard system, and then the disc rotates toward the outer circumference and records one frame per rotation.
Playback is performed and one side is recorded for 30 minutes, and as shown in Figure 1, on inner track 2 of disk 1, one horizontal period is recorded.
On the outer circumferential track 3, the image quality is good due to the wide band and good image quality. Therefore, in order to extend the recording and reproducing time, attempts have been made to reduce the number of rotations of the disk 1 toward the outer circumference so as to keep the running speed on the track constant.
However, when running at this constant speed, the number of frames recorded in one revolution of the disk 1 is not an integer, which causes problems in special reproduction such as stop motion or slow motion reproduction.

This idea was made with the aim of solving this problem.The disk surface is divided into a plurality of areas from the inner circumferential side to the outer circumferential side in the radial direction, and the number of frames recorded per revolution on the outer circumferential side is n of the number of frames recorded per revolution on the inner circumferential side
(where n is an integer), and the number of rotations of the disk is
The ratio is set to 1/n on the outer circumferential side.

FIG. 2 is a diagram showing a recording pattern of an embodiment of this invention, which is divided into two regions, an inner region A and an outer region B, with a circle 4 indicated by a chain line as a boundary.
The recording is one frame per revolution, and the outer peripheral area B is one frame.
This is a two-frame rotation.

In this way, there is no big difference between the length 1 of one horizontal period in the inner peripheral area A and the length 1' of one horizontal period in the outer peripheral area B, and the reproduced image quality hardly changes. On the other hand, since the rotation speed is halved in the outer peripheral area, the recording time is approximately 45 minutes. Note that in areas A and B, the rotation speed is switched from 1800 rpm to 900 rpm, but since 1 or 2 frames are played per rotation, special playback such as stop motion and slow motion can be performed without any problems. can.

In the above example, the disk surface was divided into two parts, the inner circumference side and the outer circumference side. However, depending on the diameter of the disk, it is divided into three or more parts, and recording is performed per rotation as the disk surface moves to the outer circumference side. The number of frames to be processed may be increased sequentially.

FIG. 3 is a block diagram showing an example of the configuration of a disc reproducing apparatus according to this invention. First, the motor 21 rotates the disc 1 at 1800 rpm. The reproduction scanning device 22 scans the disk 1 in a spiral manner from the inner circumferential side to the outer circumferential side. The signal processing circuit 23 processes the reproduced signal and converts it into a video signal. The address detection circuit 24 detects the address signal of the frame recorded during the vertical blanking period of the video signal and outputs it to the reproduction scanning device 22 as a position control signal.
A horizontal synchronization signal detection circuit 25 detects a horizontal synchronization signal from the video signal. The rotation speed switching command circuit 26 discriminates whether the reproduction area is A or B based on the period of the horizontal synchronization signal, and when it moves to area B, it gives a signal to the drive circuit 29 to switch the rotation speed to 900 rpm, and the motor 21
Change the rotation speed to 900rpm. At this time, it is desirable to use the brakes in order to quickly decelerate. 28 is a display device for a reproduced image, and 29 is a command device for starting/stopping the entire apparatus, selecting an address, specifying a reproduction mode, etc.

This idea divides the recording surface into multiple areas in the radial direction, and makes the number of frames recorded per revolution in the outer area an integral multiple of that in the inner area, which allows for longer recording times and special This has the effect of making playback possible.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a recording pattern of a conventional disc, FIG. 2 is a diagram showing a recording pattern of an embodiment of this invention, and FIG. 3 is a block diagram of a disc reproducing apparatus according to this invention. In the figure, 1 is a disk, 2 is a recording track in an inner area, 3 is a recording track in an outer area, and 4 is a recording track in an outer area.
is the boundary between the inner and outer regions. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims for Utility Model Registration] (1) Information that divides the recording surface into a plurality of areas in the radial direction, and sets the number of frames recorded per revolution in the outer area as an integral multiple of that in the inner area. recording disk. (2) The information recording disk according to claim 1, wherein the disk surface is divided into two areas, and the inner circumferential side records one frame per revolution, and the outer circumferential side records two frames per revolution.