JPH06176377A - Multihead type optical disk device - Google Patents

Abstract

PURPOSE:To reduce the occupancy space of a mechanism part and to facilitate relative positional adjustment in an optical head in a multihead type optical disk device placing the even number of optical heads on a moving means and scanning both surfaces of an optical disk by two moving means. CONSTITUTION:This device is provided with the optical heads 21, 22 scanning a track on the first recording surface 2 of the optical disk 1 and the moving means 23 and the optical heads 24, 25 scanning the track on the second recording surface 3 and the moving means 26. When the moving means 23, 26 are moved in the central direction of the disk and in an opposite direction respectively, the signals are recorded or reproduced simultaneously on the sectors of respective tracks by the optical heads 21, 25, 22, 24. Thus, relative positional adjustment work for respective optical heads are facilitated. Further, the miniaturization of an optical disk drive part is facilitated, and the further increase in the multiheads is possible as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-head type optical disc apparatus which records or reproduces signals on an optical disc at high speed using a plurality of optical heads.

[0002]

2. Description of the Related Art In applications requiring high-speed information transfer such as recording / reproducing of digital image information, the transfer speed is often insufficient with a single head. There has been proposed an optical disk device which has an improved transfer speed. As a recording method using a multi-head, an MCA that achieves both a substantially constant recording density and high-speed access by changing the information recording rate while keeping the disk rotation speed constant.
A V (improved constant angular velocity) system has been proposed, and one example thereof is disclosed in Japanese Patent Laid-Open No. 63-161532.

As a conventional example, a multi-head type optical disk device disclosed in Japanese Patent Laid-Open No. 63-161532 will be described. FIG. 7 is a plan view and a side view showing the configuration of a MCAV multi-head type optical disc device in which four independent optical heads are used. In the figure, an optical disc 1 is a disc having recording media on both sides for recording and reproducing signals. The optical disc 1 has a first
Recording surface 2 and a second recording surface 3 is formed on the lower surface.

Spiral optical track grooves are formed on the first and second recording surfaces 2 and 3. The groove is composed of m tracks with one track of the disk as one track, and each track is divided into a plurality of sectors. A sector address is recorded in advance at the beginning of each sector, and data is recorded and reproduced from the sector address until immediately before the next sector. Here, for convenience, the area on the outer peripheral side of the first recording surface 2 is Uo, and the area on the inner peripheral side is U.
Similarly, the area on the outer peripheral side of the second recording surface 3 is called L
o, the region on the inner peripheral side will be referred to as Li. Each area Uo, Ui, Lo, Li has the same number of tracks.

The optical heads 4 and 5 are heads for recording or reading information on the first recording surface 2, and are driven in the radial direction by moving means 8 and 9, respectively. The optical heads 6 and 7 are heads that record or read information on the second recording surface 3, and are driven by the moving means 10 and 11 in the radial direction. As shown in the drawing, the moving means 8 and 9 and the moving means 10 and 11 which are adjacent to each other are arranged at positions so as to form an angle of 90 degrees so as not to interfere with each other. When viewed from the optical disk drive section about the rotation axis of the optical disk 1, the positions divided clockwise by 90 degrees are designated as A, B, C, and D, respectively. The moving means 8 scans the area Uo in the center direction of the optical disc 1 at the position A of the optical head 4. Further, the moving means 9 moves the optical head 5 in the area U toward the center of the optical disc 1 at the position B.
Scan i. Similarly, the moving means 10 moves the optical head 6 to D
The area Li is scanned toward the outer peripheral side in the radial direction of the optical disc 1 at the position. Further, the moving means 11 scans the area Lo toward the outer side in the radial direction of the optical disc 1 at the position C of the optical head 7.

The disk rotating means 12 is means for rotating the optical disk 1 at a constant angular velocity (CAV).

Information reading or recording operation in the multi-head type optical disc device having the above-described structure will be briefly described. When the optical disc 1 is driven by the disc rotating means 12 at a constant angular velocity, the optical heads 4, 5, 6, and 7 simultaneously scan the tracks of the areas Uo, Ui, Li, and Lo, respectively. The recording format of the areas Uo and Li is determined so that the total number of sectors accessed by the optical heads 4 and 6 is always constant. Similarly, the recording formats of the areas Ui and Lo are determined so that the total number of sectors accessed by the optical heads 5 and 7 is always constant. Therefore, the total number of sectors accessed by the four optical heads 4 to 7 is always constant irrespective of the radius of the track, and the information transfer rate is kept constant even if the linear velocity is different between the outer peripheral portion and the inner peripheral portion of the optical disc 1. Recording or reproduction of signals is simultaneously performed so as to be constant.

[0008]

However, in such a conventional structure, the four optical heads 4 to 7 and the moving means 8 to 11 are used.
Are provided at different positions A to D respectively, so that mechanical parts such as moving means are required for the number of optical heads. Further, since the optical heads 4 to 7 are arranged at the four positions A to D of the optical disk drive unit, the entire moving means 8 to 11 occupy a large space in the device. Further, there is a problem that the disc loading mechanism for inserting or ejecting the optical disc 1 into or from the optical disc drive section becomes complicated, the design thereof is restricted, and the size of the optical disc drive section becomes large.

In particular, when the timings of recording and reproducing signals are adjusted in each of the optical heads 4 to 7, the timings of recording and reproducing signals of information are respectively deviated due to the deviation of the relative positional relationship of the optical heads 4 to 7. There was a problem that was generated. Among the four optical disks 4 to 7, the angular error of two optical heads with respect to the center of the optical disk 1 can be about 0.1 degree at maximum, but this causes a deviation of 87 μm on a track with a radius of 50 mm. Equivalent to. This value is
It is much larger than the minimum recording mark length (usually less than 1 μm), and it is necessary to secure the relative positions of the optical heads 4 to 7 with higher accuracy. However, in order to perform the positioning of the four optical heads 4 to 7, it is necessary to adjust the relative positions of the three sets of the optical heads 4 to 2 by two, which requires high-precision component processing, and There was a drawback that adjustment was time-consuming.

The present invention has been made in view of the above conventional problems, and is compact, has a small number of mechanical parts, has a large degree of freedom in designing an optical disk loading mechanism, and has a positional relationship of optical heads. It is an object of the present invention to realize a multi-head type optical disc device that can be easily adjusted.

[0011]

According to the present invention, one surface is first
Recording surface and the other is the second recording surface, and track grooves for recording or reproducing a signal are provided on the first and second recording surfaces, respectively, and the first and second recording surfaces are formed on the outer peripheral portion. An optical disc divided into a recording region and a recording region of an inner peripheral portion, and first to nth optical heads configured to move integrally for scanning the outer peripheral portion and the inner peripheral portion of the first recording surface of the optical disc. , An n + 1 to 2n optical heads configured to move integrally for scanning the outer peripheral portion and the inner peripheral portion of the second recording surface of the optical disc, and slidably the first to nth optical heads. 1st moving means for mounting and moving in the radial direction of the optical disk to guide the 1st to n-th optical heads to the track groove, and the n + 1st to 2n-th optical heads are slidably mounted, It moves in the radial direction of the optical disk in synchronization with the first moving means to move from the (n + 1) th to the 2nth Second for guiding the head to the track groove
And a means for moving the same.

[0012]

According to the present invention having such features, the first
The second recording surface is divided into an outer peripheral recording area and an inner peripheral recording area, and an optical disk having a plurality of tracks and a plurality of sectors obtained by dividing the tracks is mounted on an optical disk device. Then, the first to nth optical heads configured to move integrally to scan the outer peripheral portion and the inner peripheral portion of the first recording surface of the optical disc are provided, and the outer peripheral portion and the inner peripheral portion of the second recording surface are provided. There are provided n + 1 to 2n optical heads configured to move integrally for scanning. The first moving means slidably mounts the first to nth optical heads and moves them in the radial direction of the optical disk to guide the first to nth optical heads to a target track. Similarly, the second moving means slidably mounts the (n + 1) th to the 2nth optical heads, moves in the radial direction of the optical disk in synchronization with the first moving means, and moves from the (n + 1) th to the 2nth optical head. To the target track.
By doing so, the number of parts of the mechanical portion can be reduced and the occupied space can be reduced as compared with the case where the moving means is separately provided for each optical head. Further, since the relative positional accuracy of the optical heads mounted on the same moving means can be easily ensured, the labor of adjustment can be saved.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A multi-head type optical disk device according to an embodiment of the present invention will be described with reference to FIGS. 1A and 1B are a plan view and a side view, respectively, showing the configuration of the multi-head type optical disc device of this embodiment. The same parts as those in the conventional example are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 1B, the optical disc 1 has a first recording surface 2 on the upper surface and a second recording surface 3 on the lower surface. The optical heads 21 and 22 are heads for scanning the outer peripheral area Uo and the inner peripheral area Ui of the first recording surface 2 toward the center of the optical disc 1 in the radial direction, and the first moving means 23. It is held slidably on. Optical head 2
4, 25 are areas Lo of the outer peripheral portion of the second recording surface 3,
A head that scans the area Li of the inner peripheral portion toward the outer peripheral side in the radial direction of the optical disc 1 and is slidably held by the second moving unit 26.

As shown in FIG. 1A, the optical heads 21 and 22 and the optical heads 24 and 25 can independently access each other at the same time and record or read a signal. The moving means 23 and 26 are the optical disc 1.
Since the optical heads 21 and 22 are opposed to each other with the optical heads 21 and 22 interposed therebetween.
The optical heads 24 and 25 are located on the same vertical plane including the center of the optical disc 1. Further, the disk rotating means 12
Is a means for rotating the optical disc 1 at a constant angular velocity.

Next, FIGS. 2 and 3 are plan views showing the track and sector configurations on the first and second recording surfaces 2 and 3 of the optical disk 1, respectively. In FIG. 2, the groove 31
Is an optical track groove formed in a spiral shape on the first recording surface 2 of the optical disc 1. Although the actual optical disc 1 has tens of thousands of tracks on the first and second recording surfaces 2 and 3, ten tracks are provided on each recording surface for simplification of description. I will explain. Each track is divided into a plurality of sectors, and the signal recording area of the nth sector of the mth track is expressed as [m, n].

Reference numeral 32 indicates an address information recording portion of the signal recording area [0,0] of the first sector (sector 0) included in the outermost track (track 0), and 33 indicates the signal recording area [0,17]. The address information recording part of is shown. Reference numeral 34 indicates an address information recording section of the signal recording area [4, 0], and 35
Indicates the address information recording section of the signal recording area [4, 13]. Thus, the signal recording areas [0,0] to [0,1
7] ... The signal recording areas [4, 0] to [4, 13] are included in the area Uo, and the signal is recorded or read by the optical head 21.

Next, 36 indicates an address information recording section of the signal recording area [0, 28], and 37 indicates an address information recording section of the area [0, 41]. 38 and 39 are included in the innermost groove of the first recording surface 2 respectively, and the signal recording area [4,
28] and [4, 37] are shown.
In this way, the signal recording areas [0, 28] to [0, 41]
..Signal recording areas [4, 28] to [4, 37] are areas U
The signal is included in i and the signal is recorded or read by the optical head 22.

In FIG. 3, a groove 40 is an optical track groove spirally formed on the second recording surface 3 of the optical disc 1. Reference numeral 41 indicates an address information recording portion of the signal recording area [0, 18] of the first sector (sector 18) included in the innermost track (track 0), and 42 indicates the address of the signal recording area [0, 27]. An information recording part is shown. Again 43
Indicates the address information recording section of the signal recording area [4, 14],
Reference numeral 44 indicates an address information recording section of the signal recording area [4, 27]. In this way, the signal recording areas [0, 18] to [0, 2]
7] ... The signal recording areas [4, 14] to [4, 27] are included in the area Li, and signals are recorded or read by the optical head 25.

Next, 45 indicates an address information recording portion of the signal recording area [0, 42], and 46 indicates a signal recording area [0, 55].
The address information recording part of is shown. 47 and 48 are included in the outermost grooves of the second recording surface 3, respectively, and indicate the address information recording portions of the signal recording areas [4, 38] and [4, 55]. In this way, the signal recording areas [0, 42] to [0, 5]
5] ... The signal recording areas [4, 38] to [4, 55] are included in the area Lo, and the signal is recorded or read by the optical head 24.

In this example, the number of sectors increases by 2 every two tracks from the inner circumference to the outer circumference of the optical disc 1. The number of divisions of the sector is changed in the inner peripheral portion and the outer peripheral portion of the optical disc 1 so that the recording linear density is kept constant in all the portions of the track.

Since the actual track pitch of the optical disc 1 is about 1 μm, the number of tracks having the same number of sectors is 1000, and there are tens of thousands of tracks on one side of the disc.

Next, an example of moving means for the optical heads 21, 22, 24 and 25 will be described with reference to FIG. See also FIG.
(A) and (b) are respectively a plan view and a front view showing a specific configuration of the moving means 23, 26 of the optical head of the multi-head type optical disk device. In this figure, moving means 23, 2
6 has a mechanism of the same structure. The optical heads 21 and 22 are mounted on a frame 23a, and are slidably held by two guide shafts 23c via a plurality of rollers 23b attached to the outer peripheral portion thereof.

One of the frames 23a has a drive coil 23d.
Is formed into a tubular shape and is combined with a fixed field portion to form a linear motor. In this way, the optical heads 21 and 2
In No. 2, the linear motor is mounted on the same moving means 23 to perform the coarse movement positioning of the optical disc 1 in the radial direction.

The operation of the thus constructed multi-head type optical disc apparatus of this embodiment will be described with reference to the drawings. 5 and 6 are explanatory views showing the track arrangement and sector distribution of the optical disc 1. Here, consider a case where image information of one screen is recorded on the 0th track of the optical disc 1.
First, the optical disc 1 is rotated by the disc rotating means 12 at a constant angular velocity. When an image signal is input, the signal is divided and given to the optical heads 21 to 25, and recording is started at the same time.

The signal given to the optical head 21 is recorded in a predetermined number of bytes in the signal recording area [0, 0] of the address information recording section 32. Then, the signals are sequentially recorded in the 18 sectors up to the signal recording area [0, 17] of the address information recording unit 33. At the same time, the optical head 25 moves to the area L of the optical disc 1.
i is scanned to start recording a signal from the signal recording area [0, 18] of the address information recording unit 41 of FIG.
The signal is recorded in 10 sectors up to the signal recording area 2 [0, 27].

At the same time, the optical head 22 scans the area Ui of the optical disc 1, starts recording a signal from the signal recording area [0, 28] of the address information recording section 36 shown in FIG. 6, and outputs the signal of the address information recording section 37. A signal is recorded in 14 sectors up to the recording area [0, 41]. At the same time, the optical head 24 scans the area Lo of the optical disc 1, and the address information recording section 4 shown in FIG.
5. Start recording signals from the signal recording area [0, 42] of 5,
The signal is recorded in 14 sectors up to the signal recording area [0, 55] of the address information recording unit 46. In this way, the optical heads 21, 22, 24, 25 simultaneously start recording on the 0th track, and signals are recorded in a total of 56 sectors.

In this way, the optical heads 21, 22, 24, 2
0 scans each area in the radial direction of the disk
Signals are sequentially recorded from the track to the fourth track, which is the final track. To briefly describe the recording order on the fourth track, the optical head 21 scans the area Uo, and from the signal recording area [4, 0] of the address information recording section 34 to the signal recording area of the address information recording section 35 shown in FIG. A signal is recorded in 14 sectors up to [4, 13]. At the same time, the optical head 2
5 scans the area Li, and the address information recording unit 43 shown in FIG.
The signal is recorded in 14 sectors from the signal recording area [4, 14] of [4] to the signal recording area [4, 27] of the address information recording unit 44. At the same time, the optical head 22 scans the area Ui, and the signal recording areas [4, 2] of the address information recording section 38 shown in FIG.
8] to the signal recording area [4, 3] of the address information recording unit 39.
7] to record signals in 10 sectors. Further, at the same time, the optical head 24 scans the area Lo, and in the 18 sectors from the signal recording area [4, 38] of the address information recording section 47 to the signal recording area [4, 55] of the address information recording section 48 shown in FIG. Record the signal. In this way, a total of 56 tracks on the 4th track
A signal is recorded in the sector.

As described above, the first track of any track
The total number of sectors on the recording surface 2 and the second recording surface 3 is 56. Therefore, the four optical heads 21, 22, 2
The total number of sectors accessed by 4 and 25 is constant regardless of the radius of the track. That is, even if the number of revolutions of the optical disk 1 is constant and the peripheral speed of the track changes, the information transfer rate becomes constant.

In the present embodiment, the moving means 23 and 26 are arranged at opposite positions with the optical disk 1 sandwiched therebetween, and the case where the moving means 23 and 26 are the most compact has been shown. It suffices to select a position advantageous in mechanical design. In addition, although the recording and reproducing in the MCAV system have been described in the present embodiment, the CLV (constant linear velocity) system and the CA system.
It can also be applied to the V (constant angular velocity) method.

Further, in the case of a multi-head type optical disk device, a semiconductor laser, which is a laser light source of an ordinary optical head, requires a larger recording power toward the outer peripheral side of the disk. Therefore, the optical heads 21 and 24 on the outer peripheral side deteriorate the semiconductor laser earlier than the optical heads 22 and 25 on the inner peripheral side. However, if the optical heads 21, 22, 24, 25 and the moving means 23, 26 are configured as one unit, it is relatively easy to switch the positions of the inner optical head and the outer optical head. Can be done. Therefore, the moving means 23 and 26 may be provided with a mechanism for reversing the positions of the optical heads 21 and 22 and 24 and 25. Further, in this embodiment, two optical heads are provided on each of the first and second recording surfaces 2 and 3, but n optical heads may be provided on each of the moving means 23 and 26. In this case, the signal transfer rate can be further improved.

[0032]

As described above, according to the present invention, since the pair of optical heads are mounted on the common moving means, it is not necessary to separately provide the moving means corresponding to each optical head. Therefore, it is possible to reduce the number of mechanical components of the optical head driving unit, increase the degree of freedom in designing the loading mechanism of the optical disc, and reduce the device size. Therefore, more multi-heads can be easily accommodated. Furthermore, the relative position accuracy of the optical head can be easily secured,
The labor of position adjustment can be saved.

[Brief description of drawings]

FIG. 1 is a plan view and a side view showing a configuration of a multi-head type optical disc device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a track configuration on a first recording surface of an optical disc used in the multi-head type optical disc device of the present embodiment.

FIG. 3 is an explanatory diagram showing a track configuration on a second recording surface of an optical disc used in the multi-head type optical disc device of this embodiment.

4A and 4B are a plan view and a front view showing a configuration of a moving means of the multi-head type optical disc device of this embodiment.

FIG. 5 is an explanatory diagram (1) showing a track arrangement and a sector distribution of the optical disc of the present embodiment.

FIG. 6 is an explanatory view (No. 2) showing the track arrangement and sector distribution of the optical disc of the present embodiment.

7A and 7B are a plan view and a front view showing a configuration of a conventional 4-head type optical disc device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 optical disk 2 first recording surface 3 second recording surface 12 disk rotating means 21, 22, 24, 25 optical head 23, 26 moving means 23a frame 23b roller 23c guide shaft 23d driving coil 31, 40 groove 32 to 48 address Information recording area Li, Lo, Ui, Uo area

Claims (1)

[Claims] 1. One surface is a first recording surface and the other surface is a second recording surface, and track grooves for recording or reproducing a signal are provided on the first and second recording surfaces, respectively, and An optical disc in which the first and second recording surfaces are divided into an outer peripheral recording area and an inner peripheral recording area, respectively, and the optical disk is moved integrally to scan the outer peripheral portion and inner peripheral portion of the first recording surface of the optical disc. First to nth optical heads configured to perform the above, and n + 1th to 2nth optical heads configured to move integrally to scan the outer peripheral portion and the inner peripheral portion of the second recording surface of the optical disc. And first moving means for slidably mounting the first to nth optical heads and moving them in the radial direction of the optical disk to guide the first to nth optical heads to the track grooves. And the n + 1 to 2n optical heads are slidably mounted,
A second moving unit that moves in the radial direction of the optical disk in synchronization with the first moving unit to guide the (n + 1) th to (2n) th optical heads to the track groove. Multi-head type optical disk device.