JPH0546998A - Disk reproducing device - Google Patents

Abstract

PURPOSE:To reduce the access time of an optical pickup when data continuously recorded on a plurality of disks are reproduced. CONSTITUTION:A plurality of disks are arranged in a piled-up state. An optical pickup which rotates the disks in an integral state and is composed of a plurality of sub-arms respectively corresponding to the disks and one laser source is provided. Then data recorded on prescribed ones of the disks are continuously reproduced. Therefore, a disk device having a small size and simple structure can be obtained with one spindle and one laser source.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc reproducing apparatus suitable for continuously or simultaneously reproducing an optical disc.

[0002]

2. Description of the Related Art Conventionally, an autochanger is well known as a disc reproducing apparatus for continuously reproducing a plurality of optical discs. Although various structures have been proposed for this autochanger, as a general one, CDs are placed on a plurality of vertically stacked shelves, and a disc reproducing device (or Shelf board storage)
Up and down like an elevator, stop the disc playback device (or shelf storage part) at a predetermined CD position, remove the selected CD from the shelf plate, place it on the disc playback device, and pick up the optical pickup. Is configured to be moved to continuously reproduce a plurality of discs.

A larger turntable is prepared, a plurality of discs such as CDs are radially arranged in parallel on the turntable, and a predetermined CD is rotated at one optical pickup position on the turntable. It has been known that such a device has been brought in and played continuously.

[0004]

According to the above autochanger, a plurality of C's can be formed by one optical pickup.
D can be continuously reproduced. But multiple CDs
Requires a drive means for moving the turntable, shelf storage part or disk reproducing device like an elevator, which makes it possible to rotate in advance, and further loads or mounts the CD selected from these CD storing parts on the disk reproducing device. There is a drawback that a mechanism is required and the device becomes large.

On the other hand, in addition to those such as CDs and CDVs in which digital audio and video with audio can be inserted, a CD size of a software such as a CD in which a moving image is digitally recorded within the same diameter as a 12 cm CD is inserted. Considering LDs, the playback time per disc is shorter than that of LDs with diameters of 20 and 30 cm, so it becomes shorter. For example, it is necessary to replace at least two discs to play back one hour of video software. Will be done. Especially when the software is a movie, it is necessary to perform operations that will not be interrupted in the middle.

As a method of preventing such breakage, a semiconductor memory or the like is used, and the optical disk is rotated in the vicinity of the final track of the first optical disk and stored in the semiconductor memory at high speed, and then stored in the second optical disk. It is known that the data stored in the semiconductor memory is read out at a low speed during the access, but there is a problem that the storage capacity of the semiconductor memory becomes considerably large when the software is a movie.

The present invention has been made in order to solve the above problems, and an object of the present invention is to reproduce a plurality of optical disks continuously or simultaneously by using one optical pickup and to provide a break period. The present invention is intended to provide a disk reproducing device which can shorten the length and continuously reproduce by using a small-capacity semiconductor memory.

[0008]

DISCLOSURE OF THE INVENTION The disc reproducing apparatus of the present invention is arranged so that a plurality of discs 5a to 5d are stacked, as shown in FIG.
A plurality of sub-arms having disk drive means 1 for simultaneously rotating a to 5d by one drive means, objective lenses 12a to 12d arranged to face a plurality of disks 5a to 5d, and detectors 23a to 23d for detecting reproduction data. 7a ~
7d and one laser source 12 are arranged in the sub arm 7a
Optical pickup means 6 composed of a cylindrical main shaft 8 to which 7d are fixed, a laser beam from a laser source 12 is dispersed in the axial direction of a plurality of sub-arms 7a to 7d, and is passed through objective lenses 12a to 12d. Then, the predetermined disks 5a to 5d are reproduced.

[0009]

In the disc reproducing apparatus of the present invention, when a plurality of discs are continuously reproduced by one optical pickup, the optical pickup can quickly and quickly access from the end of the first disc to the start of the second disc. Can be performed, and by reproducing a plurality of discs at the same time, a disc having a long reproduction time can be reproduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a disk reproducing apparatus of the present invention will be described below using a single laser diode.
That is, LD of the same size as CD (hereinafter referred to as CD-LD)
The case of reproducing will be described in detail.

FIG. 1 is a perspective view showing the external appearance of a drive unit for a CD-LD 5a-5d and an optical pickup according to the present invention.
Is a spindle motor that drives multiple CD-LDs,
A coupling 4b is attached to the rotary shaft 2 of the spindle motor 1.
Through multiple spindle hubs 3a, 3b, 3c, 3d
The main shaft 4a having is fixed.

A CD-L is attached to the spindle hubs 3a to 3d.
D5a to 5d are placed and clamped, and are integrally rotated in the counterclockwise direction as indicated by an arrow by the rotation of the spindle motor 1, for example.

The optical pickup device 6 comprises a cylindrical main shaft 8 and four sub arms 7a, 7b, 7c and 7d. Objective lenses 12a to 12d, which will be described later, are attached to the tips of the sub-arms 7a to 7d.
Is movable in the radial direction and is rotated integrally with the main shaft 8.

FIG. 2 shows an embodiment of the optical system in the optical pickup device 6 described above.

In FIG. 2, the first to fourth CD-LDs 5a to 5d are a plurality of spindle hubs 3a to 3d fixed to the main shaft 4a so that they can be simultaneously rotated by one spindle motor 1.
The center hole of the CD-LD is fitted in and is held by a clamp mechanism (not shown). Reference numeral 9 denotes a chassis, and the rotary shaft 2 of the spindle motor 1 has a chassis 9 through a bearing 10a.
It projects upward and is coupled to the main shaft 4a via a coupling 4b.

FIG. 2 is a side sectional view of an optical system path built in the sub-arms 7a to 7d and the main shaft 8 constituting the optical pickup device 6. As shown in FIG. The plurality of sub arms 7a to 7d as well as the main shaft 8 are integrally rotated by the drive motor 11 for the optical pickup. For this reason, the lower end of the main shaft 8 is attached to the chassis 9
On the other hand, the main shaft 8 is fixed to the rotary shaft of the optical pickup drive motor 11 via the bearing 10b, and the objective lenses 12a to 12d of the sub arms 7a to 7d are guided to the predetermined radiation of the CD-LDs 5a to 5d. Rotate to the directional position.

A laser diode 12 for emitting a laser beam is fixed to the lowermost end of the main shaft 8, and the laser beam from the laser diode 12 is converted into parallel light by a collimator lens 13. The laser beams formed in parallel by the collimator lens 13 are relay pair lenses 14a and 14b.
The light beam is incident on and the focus is adjusted. That is, the lens 14a is fixed inside the cylinder of the main shaft 8, and the lens 14b is configured so that the parallelism can be adjusted by moving the lens 14b in the laser beam axial direction by the voice coil 15 or the like. The laser beam that has passed through the focus-adjusted relay pair lenses 14a and 14b is incident on the half-wave plate 16d, the polarization direction of the laser beam is rotated, and is incident on a polarization beam splitter (hereinafter referred to as PBS) 17d.

One quarter of the light quantity of the laser beam incident on the PBS 17d is reflected in the axial direction of the fourth sub arm 7d,
3/4 of the other amount of light is transmitted. The laser beam reflected in the axial direction of the sub-arm 7d passes through the quarter-wave plate 18d, enters the reflection mirror 19d, is reflected, and then is reflected by the objective lens 12d on the CD-LD 5d to form the reproduction spot 2.
0d is formed.

The reflected light from the CD-LD 5d is an objective lens 12d → a reflecting mirror 19d → a quarter wave plate 18d → PB.
The four-divided photodetector 2 is passed through S17d and via a light receiving lens 21d and a collimating lens 22d which form an optical system of a light receiving system path arranged at the rear part of the sub arm 7d.
The reflected light is incident on 3d, and the reflected light is converted into an electric signal to extract an RF signal, a focus error signal, a tracking error signal, and the like.

The laser beam having a light amount of 3/4 that has passed through the PBS 14d passes through the ½ wavelength plate 16c disposed in the main shaft 8 and is then provided in the PBS 17 disposed in the third sub-arm 7c.
At c, the light amount of the 1/4 laser beam is dispersed and the light amount of 2/4 is transmitted. The split laser beam forms a spot 20c on the CD-LD 5c via the reflecting mirror 19c and the objective lens 12c in the third sub-arm 7c.
This reflected light is the objective lens 12c → reflection mirror 19c → 1
/ 4 wave plate 18c → PBS 17c → light receiving lens 21c →
The light enters the four-divided photodetector 23c through the optical path of the collimator lens 22C and converts the recording data on the CD-LD 5C into an electric signal.

The laser beam having a light amount of 2/4 that has passed through the PBS 17c is rotated by the half-wave plate 16b, and 1/4 of the light amount is dispersed by the PBS 17b arranged in the second sub-arm 7b, and 1/4 is transmitted, The transmitted laser beam is split through the half-wave plate 16a by the PBS 17a provided in the first sub-arm 7a, and all of the quarter of the light amount is dispersed.

Quarter wave plates 18b and 18a and a reflecting mirror 19b are provided in the second and first sub-arms 7b and 7a.
And 19a, objective lenses 12b and 12a, light receiving lenses 21b and 21a, collimator lenses 22b and 22a.
The four-division photo detectors 23b and 23a are arranged in parallel, and the same operation as the third and fourth sub-arms 7c and 7d is performed.
The pits of the recording data of the CD-LDs 5b and 5a are made incident on and are converted into electric signals.

The laser beam emitted from the laser diode 12 is transmitted through the above-mentioned optical system path to the half-wave plates 16d and 16d.
c, 16b, 16a and PBS 17d, 17c, 17
In order to divide b and 17a into equal intensities, the following formula may be used. P ₁ = P ₀ sin 2θ ₁ P ₂ = P ₀ cos 2θ ₁ sin 2θ ₂ P ₃ = P ₀ cos 2θ ₁ cos 2θ ₂ sin 2θ ₃ P ₄ = P ₀ cos 2θ ₁ cos 2θ ₂ cos 2θ ₃ sin 2θ ₄

Here, P ₁ , P ₂ , P ₃ , P _4, ... Are shown in FIG.
As described above, the amount of light reflected by the PBSs 17d, 17c, 17b, and 17a, P ₀ represents the intensity of the linearly polarized beam from the laser diode 12, and the 1/2 wavelength waves 16d, 16c, and 16
b, the angle rotated by 16a.

Light from the laser diode 12 as shown in FIG.
Amount P₀When the laser beam of 4 is branched, P₁= P₀
If 1/4, θ₁Is obtained, P sequentially₁= P₂= P₃
= P _Four= 1 / 4P θ₂, Θ₃, Θ_FourStipulate
Yes.

Although some errors actually occur in each optical system, the AGC of the reproducing matrix amplifier described later is used.
Therefore, the levels of the RF signal, the tracking error signal, and the focus error signal may be made uniform.

In FIG. 4, sub arms 7a, 7b, 7c
4-division photo detectors 23a to 23 arranged at the rear end of the
The electrical output extracted from d is the matrix amplifier 24a.
~ 24b. First matrix amplifier 24
In a, the RF signal RF ₁ and the focus error signal FE ₁ as well as the tracking error signal TE ₁ are output, and the first to third four-pole single-throw switches 2 forming the multiplexer 25 are formed.
It is connected to the fixed contacts 6a, 26b and 26c.

Similarly, second to fourth matrix amplifiers
RF signal RF in 24b to 24d ₂, RF₃, R
F_Four, Focus error signal FE₂, FE₃, FE_Four,
Tracking error signal TE₂, TE₃, TE_FourIs output
And the first to third four composing the multiplexer 25.
They are respectively connected to the fixed contacts of the pole single throw switch.

The first to third switches 26a, 26b,
26c 4-pole single-throw contact pieces are commonly connected to output terminal 2
7a, 27b, 27c, and RF signal RF ₀ , focus error signal FE ₀ , tracking error signal T
E ₀ is output.

The first to third switches 26a, 26b, 2
The contact piece 6c is turned on / off by a switching signal supplied from the CPU or the like to the input terminal 28.

The first to fourth CD-LDs 5a to 5d reproduced by the optical pickup device 6 having the above-mentioned structure are, for example,
It is assumed that one story movie is composed of a plurality of CD-LDs 5a to 5d on which image data of different movies and the like are recorded and which are mounted on the spindle hub.

In order to explain the operation of the disc reproducing apparatus having the above structure, first, the spindle motor 1 is driven to drive a plurality of Cs.
The D-LDs 5a to 5d are similarly rotated. Next, the drive motor 11 for driving the optical pickup device 6 is energized to
Of the first C generated by the objective lens 12a of the sub-arm 7a of
The spot 20a on the D-LD 5a is brought to the lead-in position on the innermost track of the track.

In this case, since there is only one relay pair lens 14a, 14b arranged in the cylindrical main shaft 8, the focus adjustment is made so that the spot 20a is focused on the first CD-LD 5a. A focus servo error signal FE ₁ for driving the voice coil 15 to move the lens 14b in the axial direction of the main shaft 8 is obtained at the output terminal 26b via the switch 26b, and FE ₁ = FE ₀ is set to the voice of the lens 14b. It is supplied to the coil 15.

Similarly, the tracking servo is also the first
Tracking is performed only on the spot 20a of the CD-LD 5a. That is, the four-division photo detector 23
Tracking servo error signal TE _{1 of a} is switch 2
It is obtained at the output terminal 27c via 6c and is supplied to the optical pickup drive motor 11 as TE ₁ = TE ₀ .

Reproduction R with such a servo applied
The F signal RF ₁ is output to the output terminal 27a via the switch 26a.
Is output as RF ₁ = RF ₀ and is supplied to a CRT or the like.

Before the reproduction of the first CD-LD 5a approaches the end state, the data in the vicinity of the outermost periphery is stored at high speed in the semiconductor memory as in the conventional case, and the data is read out at the normal image projection speed. , The drive motor 11 is the second CD-LD 5b
The lead-in position is quickly accessed, and the focus and tracking are adjusted to the second sub-arm 7b.

That is, at the lead-in position of the second CL-LD 5b, tracking adjustment is performed in the same manner as the focus of the spot 20b, and the tracking servo error signal TE ₂ = T.
The focus error signal FE ₂ = FE ₀ is supplied to the drive motor 11 and the voice coil 15 as well as E _0, and the reproduction RF signal RF ₂ = RF ₀ at this time is continuously output to the output terminal.

Thereafter, similarly, the third and fourth CD-LD 5c
And 5d may be continuously reproduced by the sub-arms 7c and 7d.

According to the above configuration, for example, the first CD-
The second CD-LD5b from the read-out position of LD5a
The access to the lead-in position is only to rotate the objective lenses 12a and 12b in the radial direction of the CD-LDs 5a and 5b. Since there is no operation such as loading, the access can be performed in an extremely short time. The capacity of the semiconductor memory for continuing the cut can be made extremely small.

In the above embodiment, the first to fourth CD-LDs are used.
In the above, the case of sequentially reproducing from the above is explained, but the reproduction order can be from the lower side to the upper side or randomly.

Further, the case where the main shaft 8 of the optical pickup device is rotatably fixed to the chassis 9 has been described, but the entire optical pickup device 6 is linearly moved in the radiation direction of the CD-LD by using the voice coil motor (VCM). It may be configured to move.

Further, the objective lenses 12a to 12 shown in FIG.
If b is held by a two-axis device, servo is applied so that tracking servo is performed individually in focus, and the relay pair lenses 14a and 14b are omitted and access is performed by the drive motor 11, a plurality of CD-LDs 5a can be obtained. It is also possible to reproduce ~ 5d at the same time.

[0043]

According to the disc reproducing apparatus of the present invention, the access time can be greatly reduced when continuously reproducing discs continuously recorded on a plurality of discs, and at the same time, it is compact and simple with one spindle motor and one laser source. A disc reproducing apparatus having a different structure can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a disc reproducing apparatus of the present invention.

FIG. 2 is an optical system path diagram of an optical pickup used in the disc reproducing apparatus of the present invention.

FIG. 3 is an explanatory diagram of laser branch intensity of a beam splitter used in the disc reproducing apparatus of the present invention.

FIG. 4 is a detection circuit diagram used in the disc reproducing apparatus of the present invention.

[Explanation of symbols]

 1 Spindle motor 3a-3d Spindle hub 4a Spindle 5a-5d Disk 6 Optical pickup device 7a-7d Sub-arm 20a-20d Spot

Claims (1)

[Claims] 1. A disk drive means for arranging a plurality of disks so as to be stacked, and simultaneously rotating the plurality of disks by one drive means, an objective lens arranged to face the plurality of disks, and reproduction data are detected. A plurality of sub-arms having a detection unit for
And an optical pickup means composed of a cylindrical main shaft to which one laser source is provided and to which the sub-arm is fixed. The laser beam from the laser source is split in the axial direction of the plurality of sub-arms, and the objective lens is provided. A disc reproducing apparatus characterized in that a predetermined disc is reproduced through the.