JPH0371432A - Disk restoring device - Google Patents

Abstract

PURPOSE:To detect the presence/absence of a disk in a short time and to simplify constitution by detecting the presence/absence of the disk by utilizing the rotating time of a rotary table. CONSTITUTION:The device is comprised so that each disk holding part 34 can hold the disk 1 in the circumferential direction of the rotary table 30 obliquely, and when the presence/absence of the disk 1 is detected at each disk holding part 34, the objective lens 82 of a reproducing head 74 is fixed at a height position where a focal point can be obtained at either part of the disk 1. Therefore, when the disk 1 is present at the disk holding part 34, a relative distance between the disk 1 and the objective lens 82 is varied gradually by rotating the rotary table 30, which enables the focal point to be always obtained at either part of the disk, and the presence of the disk 1 can be detected. in such a way, the presence/absence of the disk 1 can be detected in a short time, and also, the constitution can be simplified.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a disc playback device in which a plurality of discs can be set in a disc holder on a rotary table, and a simple configuration for determining the presence or absence of a disc in the disc holder. It is designed to be large and can be detected in a short period of time.

[Conventional technology]

2. Description of the Related Art Conventionally, a disc playback device is known in which a rotary table having a plurality of disc holders is placed on a tray so that a plurality of discs can be set at the same time and played back continuously. In this type of disc playback device,
Immediately after storing the tray in the main body of the playback apparatus, it is necessary to detect the presence or absence of a disc in each disc holder in advance before playback.

Conventionally, to detect the presence or absence of a disc in each disc holder, a light-emitting element and a light-receiving element are installed in a tray facing the disc holder, the rotary table is rotated once, and at that time the light emitting element and the light-receiving element are installed in the tray in each disc holder. There has been a system in which the presence or absence of a disk in each disk holder is detected based on whether or not the light receiving element detects the reflected light from the disk from the element.

Another method is to rotate the rotary table once while emitting a laser beam from the reproducing head (optical recording head), and at that time, the reflected light of the laser beam is transmitted to each disk holding section for reproduction. There has been a system in which the presence or absence of a disc in each disc holder is detected based on whether or not it is detected by a light-receiving element within the disc.

[Problem to be solved by the invention]

The method of detecting the presence or absence of a disc by installing a light emitting element and a light receiving element on the tray has the disadvantage that these light emitting elements and light receiving elements, as well as their driving circuit and detection circuit, are required for exclusive use, which complicates the configuration and increases costs. was there.

In addition, in the method of detecting the presence or absence of a disc using a playback head, the configuration is simplified, but the rotation of the rotary table is stopped at each disc holder position, and the objective lens of the playback head is moved up and down to detect the disc. focus on the top,
Since the presence or absence of a disk is detected by detecting the reflected light, it takes unnecessary time to stop the rotary table and move the objective lens up and down.

This invention solves the drawbacks in the conventional techniques, and
The object of the present invention is to provide a disc playback device that has a simple configuration and can detect the presence or absence of a disc in a short time.

[Means to solve the problem]

This invention consists of a tray that is moved relative to the main body of the device to be stored and ejected, a rotary table that is rotatably attached to the tray, and a playback head that is formed around the rotary table on the rotary table and into which a playback head is inserted. a plurality of disc holders having openings formed therein, and the discs held by the plurality of disc holders are selectively placed on the turntable by rotation of the rotary table, and are reproduced by a reproducing head. In the disc playback device, each of the disc holders is configured to hold a disc inclined in the circumferential direction of the rotary table, and when detecting the presence or absence of a disc in each of these disc holders, the objective of the playback head is The lens is fixed at a height position that focuses on any part of the disc, and the rotary table is rotated to obtain a state in which the lens is focused when the playback end passes through the position of each disc holder. The apparatus further includes a disk detection device that detects the presence or absence of a disk based on whether or not the disk is detected.

[For production]

According to this invention, each disk holding section is configured to hold the disk inclined in the circumferential direction of the rotary table, and when detecting the presence or absence of a disk in each of these disk holding sections, the objective lens of the playback head is Since it is fixed at a height position where the focal point is focused at one of the parts, if there is a disc in the disc holder, rotating the rotary table will gradually change the relative distance between the disc and the objective lens. The focus will always be on some part of the disc, and the presence of the disc will be detected.

Further, if no part is focused, it is detected that there is no disc.

According to this, since the presence or absence of a disk can be detected using the rotation time of the rotary table, the presence or absence of a disk can be detected in a short time. Furthermore, since the detection is performed using a reproducing head, the configuration is simplified.

〔Example〕

Examples of this invention will be described below. FIG. 1 shows the mechanical part of a disc playback device to which the present invention is applied. The tray 26 is moved in the direction of arrow A relative to the playback device main body 28 by motor drive, and is stored and ejected. On the tray 26, a rotary table 30 is rotated by an arrow B by a motor drive.
It is mounted so that it can rotate in any direction. rotary table 3
A plurality of (five in this case) disk holding portions 34 for holding the disk 1 around the rotation center 32 are formed on the disk 0 . The disc holder 34 here includes a groove 34a for a 12 cm CD and a groove 34b for an 8 am CD. An opening 36 for inserting a turntable and a reproducing head is formed in the disc holding portion 34 toward the outer circumference of the rotary table 30.

An opening 38 is also formed in the center of the rear end of the disc tray 26, and communicates with the opening 36 of the disc holder 34 at that position, so that the turntable and the playback head can be pulled out from here while still in the playback state and removed from the tray 26. allows for the discharge of

At the center of the rear end of the mechanical chassis 40 in the playback device main body 28, a sub-chassis 42 equipped with a turntable 72 and a playback head (not shown) is mounted below the tray 26 by a motor drive as shown by arrow C. It is rotatably supported around a rotating shaft 44.

Further, a disk clamper 46 is fixedly installed on the mechanical chassis 40 above the tray 26 and facing the turntable 72.

When the sub-chassis 42 rotates upward with the tray 26 stored in the playback device main body 28, the turntable 72
Then, the playback head is raised and inserted into the opening 36 of the disc holder 34. As a result, the disc 1 is placed on the turntable 72, pulled up from the disc holder 34, and clamped by the disc clamper 46.

In this state, the playback head can perform playback.

When the sub-chassis 42 rotates downward with the tray 26 housed in the playback main body 28, the disk 1 is returned to the disk holding section 34, and the turntable 72 and playback head are pulled out downward from the opening 36. .

When the disc is ejected from the playback state, the turntable 72 and the playback head are pulled out horizontally from the opening 36° 38, so it is possible to pull out the tray 26 from the playback main body 28 and replace the disc without continuing playback. can.

After completing the disc exchange, move the tray 26 to the playback device main body 28.
, the turntable 72 and playback head are inserted into the openings 38,36.

In this way, discs can be changed without stopping playback.

FIG. 1 shows an embodiment of a disc detection device applied to the disc playback device of FIG. 2. In FIG. As shown in this figure, the vertical cross-sectional structure of the disk holding part 34 on the rotary table 30 is such that the grooves 34a and 34b are 12c+nCD and 8c, respectively.
The mCD is configured to be held tilted in the circumferential direction of the rotary table 30, that is, in the rotational direction.

When detecting the presence or absence of a disc in each disc holder 34, the reproducing head 74 is set at a predetermined height as shown in FIG. However, the disk 1 remains held by the disk holding portion 34 and is not set on the turntable 72, nor is it clamped by the disk clamper 46. Further, in response to a command from the system control 78, the switch 80 is connected to the contact a side, and a predetermined DC voltage E is applied to the focus actuator in the playback head 74, so that the height of the objective lens 82 is adjusted to the intermediate position of its movement range. set nearby.

The height position of the reproducing head 74 and the inclination angle at which the disc 1 is held at this time are such that the laser beam 76 emitted from the objective lens 82 is arranged obliquely in the groove 34a of the disc holder 34. (7) The focus is set at any mirror surface portion of the CD, and also at any mirror surface portion of the 8 cm CD arranged obliquely in the groove 34b. Further, as shown in FIG. 3, the radial position of the reproducing head 74 is such that the laser beam 76 emitted from the objective lens 82 is i2c+ncD1a and 8 cm
The light is set at a position where the mirror surface portion of either CDlb is irradiated.

A light reception signal of disk reflected light detected by the reproducing head 74 when detecting the presence or absence of a disk is input to a focus error circuit 84, and a focus error is detected. A disk presence/absence determination circuit 86 determines the presence or absence of a disk from the focus error signal.

The disk holding portion position detection circuit 89 is connected to the rotary table 30.
Which disk holder has reached the position of the reproducing head 74 is detected by a position detection notch formed on the lower surface or outer shoulder of the disc, an encoder connected to a rotary table drive motor, or the like.

The system control 78 stores the determination result in the memory 88, and displays on the display 90 which of the disk holders 34 there is a disk and which one does not.

Note that during playback, the switch 80 is connected to the contact side, and the focus control circuit 9 is activated based on the focus error signal.
A focus control signal is generated in step 2, and this signal is supplied to the focus actuator via the servo amplifier 94 to realize focus avo.

A series of disk detection operations by the disk detection device 9 of FIG. 1 will be explained. When a 12 cm CD or an 8 am CD is set in any disc holder 34 on the rotary table 30 and the tray 26 is stored in the playback main body 28, the presence or absence of the disc is detected prior to playback. That is, the reproducing head 74 is fixed at a predetermined height position and a predetermined radial position. Further, a switch 80 is connected to the contact a side. Then, the laser beam 76 is irradiated from the objective lens 82 of the reproducing head 74, and the rotary table 30 is rotated at least once.

When the rotary table 30 rotates and each disk holding section 34 passes over the playback head 74, if the disk l is held in the disk holding section 34, the playback head 74
The laser beam 76 emitted from the recording head 74 is irradiated onto the disk surface, and the reflected light is received by a light receiving element within the reproducing head 74. A focus error detection circuit 84 detects a focus error from this light reception signal, and detects a focus error from this light reception signal, and detects a disk presence/absence determination circuit 86.
determines the presence or absence of a disc from the focus error.

That is, since the disk 1 is held by the disk holder 34 at an angle in the direction of rotation of the rotary table 30, the rotation of the rotary table 30 causes the disk surface and the objective lens 8 to
The relative distance to 2 becomes gradually shorter (and the focus position is exceeded in some part).

For example, in the case of a 12 cm CD, as shown in FIG. 4, since the disk 1a is held at the upper part 34a, it passes through the focal point in the latter half of the opening 36. Also, 8 c
In the case of MCD, as shown in FIG. 5, the disk 1b is held in the lower groove 34b, so the objective lens 82
The distance between the two objects becomes shorter and the object passes through the focal point in the first half of the aperture 36.

When passing through the focus position, the focus error signal changes as shown in FIG. Therefore, the disk presence/absence determination circuit 86
detects that the focus error signal changes in such a pattern and detects that there is a disc in the disc holding section. Which disc holder is it?
The disc holding portion position detection circuit 89 detects the position.

If a tracking error signal change pattern as shown in FIG. 6 is not obtained when the disc holder 34 passes over the reproducing head 74, it is detected that no disc is set in that disc holder.

In this way, while the rotary table 30 makes one rotation, the presence or absence of a disk is detected in all the disk holders, and this information is stored in the memory 88 and displayed on the display 90. Therefore, the user can program the performance order, etc. by looking at the display.

When the program is finished and the playback button is pressed, the rotary table 30 rotates, the first selected disc holder 34 is positioned at the position of the playback head 74, and the turntable 72 is raised and A disk is set thereon (the inclination angle of the disk is small, so it can be set on the turntable 72 without difficulty), and the disk is rotated and reproduced by the reproducing head 74. When the reproduction of the first disc is completed, the second, third, . . . discs are similarly reproduced in sequence.

[Example of change]

In the embodiment described above, the height of the reproducing head was fixed during the disc detection operation, but if the focal length of the objective lens 82 is short, the reproducing head 74 is raised to a predetermined height when passing through the opening 36, By lowering the reproducing head 74 at other parts, it is possible to prevent the reproducing head 74 from colliding with the rotary table 30.

Further, in the embodiment described above, the relative distance between the disk 1 and the objective lens 82 was changed in the direction of decreasing, but it can also be changed in the direction of increasing.

〔Effect of the invention〕

As explained above, according to the present invention, the presence or absence of a disk can be detected using the rotation time of the rotary table.
The presence or absence of a disk can be detected in a short time. Furthermore, since the detection is performed using a reproducing head, the configuration is simplified.

FIG. 3 is a plan view showing the position of the reproducing head in the disk radial direction when detecting the disk.

FIG. 4 is a longitudinal sectional view showing the state of focus detection for a 12 cm CD in the apparatus of FIG. 1.

FIG. 5 shows that in the apparatus of FIG.
...Disc, 1a-12cm CD, 1
b-8cmCD, 26...Tray, 28...Player main body, 30...Rotary table 1, 32...Rotation center, 34...Disc holding part, 36...Opening part, 70... ... Disk motor, 72... Turntable, 74... Playback head.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a rotary table showing an embodiment of the present invention and a block diagram showing an example of the configuration of a disk detection device. FIG. 2 is a perspective view showing a schematic structure of a mechanical part of a disc playback device to which the present invention is applied.

Claims (1)

[Claims] A tray that is moved relative to the main body of the device to be stored and ejected;
The tray includes a rotary table rotatably attached to the tray, and a plurality of disc holders formed around a rotation axis on the rotary table and each having an opening into which a playback head is inserted. In a disc playback device in which a disc held by the plurality of disc holders is selectively placed on a turntable by rotation and is played back by a playback head, each of the disc holders moves the disc in a circumferential direction of the rotary table. When detecting the presence or absence of a disc in each of these disc holders, the objective lens of the reproducing head is fixed at a height position where it focuses on any part of the disc, and A disc playback device further comprising a disc detection device that rotates a rotary table and detects the presence or absence of a disc based on whether or not a focused state is obtained when the playback head passes through the position of each disc holding part. .