JPH04324164A - Discrimination device for front side and rear side of disk - Google Patents

Abstract

PURPOSE:To prevent from requiring a long time until the start of signal reproduction by detecting the front and rear sides of the disk before mounting the disk on the turn table and preliminarily deciding the rotation direction of the turn table. CONSTITUTION:When an information record disk 10 in which a first disk 30 provided an information record track with a swirl in the clockwise direction and a second disk 31 having a different reflactance provided the information record track with a swirl in the counterclockwise direction are stuck and formed is reproduced, photosensers 44, 60 are provided at the bottom surface or the side surface of a tray 1. With those photosensers 44, 60, the disk surface going to be abutted to the turn table 5 is discriminated whether it is either one of both disks or not and the rotary direction is decided before the drive of a spindle motor 9.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention is a method of simultaneously collecting data from both sides of an information recording disk, which is formed by bonding two information recording disks with spiral information recording tracks in different extending directions, using two pickups. The present invention relates to a disk double-sided playback device that reads signals.

0002

[Prior Art] A disc recording method for recording a broadband high-definition video signal with its baseband unchanged is to divide the high-definition video signal into two channels and record it on two types of discs, and then to record the high-definition video signal from these discs during playback. A method has been proposed in which signals are reproduced simultaneously and the respective reproduced signals are combined to restore the original high-quality video signal.

As this recording and reproducing method, the applicant of the present application previously proposed the following in Japanese Patent Application No. 114077/1999. That is, a line-sequential color video signal is distributed and recorded at a line period on a first disk in which a spiral track extends clockwise and a second disk in a counterclockwise direction, and these two disks are pasted together. to form one disc,
During reproduction, separate pickups are placed facing each other on the front and back surfaces of a disc mounted on a single turntable, and both sides are simultaneously reproduced to form the original line-sequential color video signal.

[0004] In the technique of the prior application, in order to enable simultaneous reproduction of both sides of the disc, it is essential to set the extending directions of the tracks on the front and back surfaces of the disc in the clockwise and counterclockwise directions. Therefore, it is necessary to rotate the turntable forward or reverse depending on whether the disk is mounted on the turntable. For example, if the disk surface that comes into contact with the turntable is the signal recording surface of the first disk, it is necessary to rotate the turntable in the normal direction, and if it is the signal recording surface of the second disk, it is necessary to rotate the turntable in the reverse direction. Therefore, once the disc is mounted on the turntable, rotate the turntable in the normal direction and read the signal from each signal recording surface using the two pickups. If the signal can be read, this rotation direction is suitable. If the signal cannot be read, it is assumed that the rotation direction is not compatible and it is necessary to reverse the rotation direction and read the signal.

[0005]

[Problems to be Solved by the Invention] As mentioned above, when determining the front and back sides of a disc, in a method in which signals are reproduced by rotating the disc once in a predetermined direction, if the initial rotation direction is wrong, the initial rotation After the turntable reaches a predetermined rotation speed in the direction, the signal is read for a certain period of time, and after it is detected that reading is impossible, the rotation direction is reversed and the turntable is turned to a rotation speed that makes it possible to read the signal. Signal regeneration must wait until the table is reached,
It will take extra time to start signal reproduction.

[0006]

[Means for Solving the Problems] A first disk in which information recording tracks are arranged in a clockwise spiral pattern has a different reflectance from the first disk, and the information recording tracks are arranged in a counterclockwise spiral pattern. an information recording disk formed by pasting together a second disk; a turntable that can rotate in both forward and reverse directions while supporting the disk by contacting one of the two disk surfaces; A disc transport tray that is transported onto a turntable, and a disc disposed on the tray that irradiates light onto either side of the disc and detects the level of reflected light, before the disc contacts the turntable. The present invention is characterized by comprising a discriminating means for discriminating the disk surface to be brought into contact with the turntable.

[0007]

[Operation] Since the present invention is constructed as described above, before the disc is mounted on the turntable, it is easily determined which surface of the disc is about to come into contact with the turntable, and the disc is mounted on the turntable. Once this is completed, the turntable can be driven in the correct direction of rotation.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a schematic explanatory diagram of the disc loading mechanism of a video disc player. As is well known, the tray 1 is in a state protruding from an opening 3 formed in the front panel 2 of the player body. A pinion 7, which is pivotally supported by the chassis and connected to a horizontal loading motor 6, is engaged with a rack 4 integrally formed on the lower surface, and by driving the motor 6 during disk loading, the tray 1 is moved into the player body. be accommodated in. Due to this horizontal movement, the tray 1 reaches the position shown in FIG. 1, that is, the upper position of the turntable 5, and at this point, the position detection switch 8 that contacts a part of the tray 1 is activated and the motor drive is stopped.
Horizontal movement is completed.

Next, from this position, the turntable 5 vertically rises together with the spindle motor 9 that rotationally drives the turntable 5 by a well-known mechanism (not shown), and passes through the notch 10b of the tray 1. Turntable center shaft core tool 5
While fitting the center hole 10a of the disk into the center hole 10a of the disk, place the disk 10 on the turntable 5 with the bottom surface of the disk 10 in contact with the top surface of the turntable 5, and then pull the disk 10 away from the tray 1 to connect the clamper 11 and the turntable 5. Clamp the disc between them.

Next, as shown in FIG. 4, a U-shaped guide member 15 is movably supported on a U-shaped guide member 15 composed of upper and lower linear guide parts 12 and 13 and a connecting part 14 that connects these two guide parts. Two pickups 16 and 17 simultaneously read signals from both sides of the disk. Each pickup has a pinion 21, 21 that meshes with a rack portion 20 formed on the U-shaped guide member 15, and a motor 22 that drives the pinion, and is formed on the guide member 15 to guide the movement. It is fixed on a movable base 25 having rollers 24, 24 fitted in guide grooves 23.

When reading this signal, the pickup 16 is located in the upper linear guide section 12 to read the signal from the top surface of the disk, and at the same time the pickup 17 is located in the lower linear guide section 13 to read the signal from the bottom surface of the disk. Therefore, the positions of both pickups in the disk radial direction are always controlled to be equal.

The disk 10 is formed by pasting together two disks, a first disk 30 and a second disk 31, and the first disk 30 has information recording tracks arranged in a clockwise spiral. Information is recorded on the second disk 31 in the form of information recording tracks arranged in a counterclockwise spiral. In addition, in order to easily distinguish between the front and back surfaces of the disc, that is, both disc surfaces, we have installed a high-reflection plate made of a material with high light reflectance in the non-recording area on the inner circumference side of the disc surface (first disc surface). Reflective material label 32
is attached, and a low-reflection material label 33 having a lower reflectance than the label on the front surface is attached to the back surface (second disk surface) of the disk. Specifically, color video signals are distributed line-sequentially at a line period and recorded on both disks in order to record a broadband high-quality video signal divided into two channels without changing the baseband.

Further, as shown in FIGS. 1 and 5, the tray 1 is formed with a housing section 41 for housing the disk 10, and two openings 42 and 43 are formed on the bottom surface of this housing section. has been done. The radial position of this opening varies;
When the disc is housed in the storage section, the opening 42 faces the label portion on the lower surface of the disc, and the opening 43 faces the information recording area portion on the outer periphery rather than the label portion. Further, below the openings 42 and 43, a photosensor 44 is provided.
, 45 are fixed to the lower surface of the tray 1 via attachment pieces 46 and 47 so as to be disposed upward.

The photosensor 44 is for detecting whether the surface facing the opening 42, in other words, the surface of the disk that comes into contact with the top surface of the turntable 5, is the front or back surface of the disk, and has a pair of light emitting lights. and a light-receiving element, the first disc 30 operates so that light from the light-emitting element is reflected on the lower surface of the disc, and this reflected light is received by the light-receiving element, and the lower surface of the disc has a highly reflective material label affixed thereto. If it is a surface, the reflected light level will be high, and conversely, if it is the surface of the second disk 31, the reflected light level will be low. In this manner, by monitoring the reflected light level, it is easy to determine whether the disk is front or back.

The photosensor 45 is for determining whether or not there is a disk surface facing the opening 43, and like the photosensor 44, it is composed of a pair of light-emitting and light-receiving elements. The presence or absence of the disk in the storage section 41 is detected by detecting the presence or absence of this reflected light.

Next, as shown in FIG. 3, the flowchart in FIG. 6 describes the operation of the microcomputer 50 that uses these photosensor outputs as input to control the drive of the spindle motor 9 and the position control of the pickup. Explained for reference.

Tray 1 protruding from the player body
After storing the disc 10 in the tray (STEP 100), the tray is moved horizontally (STEP 101), and when this horizontal movement is completed, the photosensor 45 detects the presence or absence of the disc (STEP 102). The result of this detection is supplied to the microcomputer 50, and when it is determined that there is no disc on the tray, the player is brought to a stop state (ST
EP103).

On the other hand, when it is determined that there is a disc, the photosensor 44 detects the front and back sides of the disc (STEP 104). The result of this front/back detection is also supplied to the microcomputer 50, and if it is determined that the disk surface facing the sensor 44 is the first disk surface, the spindle motor
The rotation direction of the rotor 9 is set clockwise, and when it is determined that it is the second disc surface, the rotation direction is set counterclockwise (STEP 1).
05). When this rotation direction setting is completed, the motor 9 moves vertically to perform disk clamping (STEP
106). When this clamping operation is completed, the spindle motor 9 starts rotating in the previously set rotation direction (S
TEP 107), and at the same time, the pickups 16 and 17 are moved to the respective inner circumferential positions on both sides of the disk (STEP 108).
), when the disk reaches a predetermined number of revolutions, it starts reading signals from the innermost circumference (STEP 109). In this way, the respective reproduced signals obtained from both sides of the disc are combined into one by a signal processing circuit (not shown) and restored to the original high-quality video signal.

In this way, before the disk is mounted on the turntable 5, the direction of rotation of the spindle motor 9, that is, the turntable, that enables signal reproduction is determined, and signal reproduction is possible in the shortest possible time.

In the above-mentioned embodiment, labels with different reflectances were attached to each side of the disk in order to distinguish between the front and back sides of the disk, but instead of this, it is possible to make the reflectance of each side of both disks different. For example, the side surface of the first disk 30 may be subjected to high reflection processing such as pasting or vapor deposition of a high reflection material, and the side surface of the second disk 31 may be left as it is or may be subjected to low reflection processing such as application of a low reflection material to increase the reflectance of both sides. 7 and 8, instead of arranging the opening 42 and the photosensor 44, a photosensor 60 is embedded in the inner surface of the tray 1, and the light emitted from the light emitting element of the photosensor 60 is directed to the disk. Irradiates only the sides of the bottom surface, detects this reflected light with a light receiving element, and if the received light output is at a high level, it is determined that the bottom surface of the disk is the first disk, and if it is low, it is determined that it is the second disk. It is also possible to configure it as follows.

Furthermore, in the above-mentioned embodiment, the turntable is raised together with the spindle motor when the disk is mounted on the turntable, but instead of this,
It is also possible to configure the tray to be lowered after horizontal movement. Furthermore, instead of fixing the photosensors 44 and 45 to the tray, it is also possible to install them in advance on the chassis so as to face the openings 42 and 43 when the horizontal movement of the tray is completed.

[0022]

As described above, according to the present invention, before the disk is mounted on the turntable, the information recording tracks on the disk surface that contacts the turntable, that is, the bottom surface of the disk, are arranged in a spiral shape in any direction. It is possible to determine whether there is a turntable, and there is no need to make a mistake in the initial rotation direction of the turntable.
This makes it possible to shorten the time required to start signal reproduction.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of an embodiment of the invention.

FIG. 2 is a perspective view of essential parts of the disc loading mechanism of the embodiment.

FIG. 3 is a circuit block diagram of the embodiment.

FIG. 4 is a diagram illustrating the reproduction operation of the embodiment.

FIG. 5 is a perspective view of the tray of the embodiment.

FIG. 6 is a flowchart of an embodiment.

FIG. 7 is a perspective view of a tray according to another embodiment.

FIG. 8 is a side sectional view of another embodiment.

[Explanation of symbols]

1 Tray 5 Turntable 10 Disc 30 1st disc 31 Second disc 44, 60 Photo sensor

Claims (1)

[Claims] 1. A first disk in which information recording tracks are spirally arranged in a clockwise direction; and a second disk in which information recording tracks are arranged in a counterclockwise spiral, the reflectance of which is different from that of the first disk. an information recording disk formed by bonding together an information recording disk, a turntable that supports the disk by contacting either one of the two disk surfaces and can be rotated integrally in both forward and reverse directions, and a turntable that houses the information recording disk. light is irradiated onto either surface of the disk transport tray to be transported onto the turntable and the surface of either of the disks is detected, and the level of reflected light is detected, and before the disk comes into contact with the turntable, the turntable is A disc front/back discriminating device includes a discriminating means for discriminating a disc surface to be brought into contact with a table.