JP2720828B2 - Optical disk apparatus and reading method therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus and a method for reading the same, and more particularly to an optical disk apparatus used for a CDROM and the like and a method for reading the same.

[0002]

2. Description of the Related Art A single-read-beam type optical disk apparatus that irradiates a single light beam to an information bit string written on an optical disk and reads the information is used to increase the data reading speed by, for example, n times. Since the number of rotations of the optical disk needs to be increased by n times, the load on the rotation mechanism and the like increases. Also,
Since data reaches the optical pickup at high speed, it is necessary to widen the bandwidth of the photoelectric conversion system.

[0003] The single reading beam has two tracking beams.
Referring to FIG. 4, which shows a block diagram of a conventional first optical disk device of a general three-beam system to which a beam is added, this conventional first optical disk device includes photoelectric conversion elements corresponding to each of three beams. Certain detectors 101, 10
And a current voltage (IV) for converting the output current of each of the photodetectors 100, 102 and 104 into voltage signals a, be to e, and g, respectively.
Conversion circuits 11, 12, and 14 and an operation circuit 17 that generates signals D, TA, and F by predetermined operation processing of signals b to e
And an arithmetic circuit 18 for generating a signal TB by subtracting the signals a and g; an amplifying / demodulating circuit 21 for amplifying and demodulating the signal D to generate a data output DO; It includes a PLL 22 that generates the signal, a focus servo circuit 15 that adjusts the focus of the photodetector 100 in response to the supply of the signal F, and a tracking servo 16 that performs tracking adjustment of the photodetector 100 in response to the supply of the signals TA and TB.

The detector 102 is divided into four for focus servo and tracking servo, and the corresponding IV conversion circuit 12 also has an IV conversion circuit 12A corresponding to the signals b to e.
~ 12D.

Referring to FIG. 4, the conventional optical disk device and its reading operation will be described. The arithmetic circuit 17 responds to the supply of the output signals b to e of the IV conversion circuits 12A to 12D. b + c + d + e = D, (b +
d)-(c + e) = TA, (b + e)-(c + d) = F
Is performed. The arithmetic circuit 18 performs an arithmetic operation of ag = TB in response to the supply of the output signals a and g of the I / V conversion circuits 11 and 14, respectively. The signals TA and TB are supplied to the tracking servo circuit 16, and the tracking servo circuit 16 performs tracking control in response to the supply of these signals TA and TB. Similarly, the signal F is supplied to the focus servo circuit 15, and the focus servo circuit 15
Performs focus control in response to the signal F. Signal D
Are supplied to an amplification demodulation circuit 21 and a PLL 22, respectively. The amplification demodulation circuit 21 demodulates the signal D to restore digital information. On the other hand, the PLL 22 generates the demodulation clock CP in response to the supply of the signal D, and supplies the demodulation clock CP to the amplification / demodulation circuit 21.

Referring to FIG. 5 which is a time chart showing the relationship between the operation of the optical pickup, the data read state, and the data output DO in units of disk rotation, data reading for one track is performed every one rotation of the disk. It is executed continuously and outputs the corresponding output data DO for one track.

As described above, in the first conventional optical disk device, it is necessary to increase the rotation speed of the optical disk in order to increase the data reading speed. IV conversion circuit 1 that constitutes
There is a problem that it is necessary to widen the bandwidths of the circuits 1, 12, and 14, the operation circuits 17 and 18, and the amplification modulation circuit 21 and the PLL 22.

In order to solve this problem, a multi-beam system has been proposed in which a plurality of tracks on an optical disk are read out in parallel using a large number of light beams.

FIG. 6 is a block diagram of a conventional second optical disk apparatus of the multi-beam system described in Japanese Patent Application Laid-Open No. 3-93049, in which constituent elements common to FIG. The difference between this conventional second optical disk device and the above-mentioned first optical disk device is that a diffraction grating (not shown) for converting a readout beam into five beams in this example is provided. And a diffraction grating servo circuit 180 for correctly aligning the five beams on the information tracks of the optical disk, and a four-divided detector 113 similar to the detector 102 corresponding to each of the five beams instead of the photodetector 100. And a photodetector 110 including detectors 111 to 115 including a two-divided detector 115, and these detectors 111 115 Output signals of I
IV conversion circuits 121 to 125 for V-conversion and arithmetic circuit 1
7, an arithmetic circuit 171 that performs a predetermined operation and outputs signals D3, F, and TA in response to the supply of the output of each of the IV conversion circuits 123 corresponding to the four-divided detector 113, and an IV conversion corresponding to the two-divided detector 115. A predetermined operation is performed in response to the supply of each output of the circuit 125 to perform the diffraction grating servo circuit 18.
The arithmetic circuit 172 which outputs the difference signal R supplied to 0 and the sum signal D5 as a data output, respectively, and the output data D1 to D5 of each of the five IV conversion circuits 121 to 125 are amplified and demodulated to output data DO1 to DO5. Amplifying decoder 2 that generates DO5 and has the same function as amplification demodulation circuit 21 and PLL 22
Storage circuits 311 to 315 for storing output data DO1 to DO5;
And a readout circuit 40 for sequentially outputting the outputs of 15 as output data DM.

The operation will be described in detail. Photo-electric conversion is performed by the photo detector 110, and each of the
Signals D1 to D5 that have been IV-converted and output at １２５125
Are demodulated by the amplification decoders 211 to 215, respectively.
The data is stored in the storage circuits 311 to 315 as demodulated data DO1 to DO5 composed of bit strings. The read circuit 40 outputs the high-speed output data DM by sequentially reading out the stored data DO1 to DO5 at a transfer rate five times as high as the read rate.

[0011]

The above-mentioned first conventional optical disk apparatus and the reading method therefor require an increase in the load on the rotation mechanism and an increase in the optical speed due to an increase in the rotation speed of the optical disk required to increase the data reading speed. IV that constitutes the electric conversion system
There is a problem that the conversion circuit, the arithmetic circuit, and the amplification modulation circuit need to have a wide band.

According to the second conventional optical disk apparatus and the reading method therefor which solve the above-mentioned problems, data corresponding to the number of beams read out by each of the multi-beams can be sequentially output. When reading data existing beyond the range of the track covered by, the data is interrupted until the track range moves to the existing range of this data, and temporally continuous data such as moving image data and audio data is read. When handling, there is a drawback that the smoothness of the motion of the image is impaired, or the sound is interrupted.

[0013]

An optical disk apparatus according to the present invention comprises an optical pickup for simultaneously reading data of a first track group consisting of N tracks on an optical disk using N (N is an integer) light beams. If, in the optical disc apparatus of a multi-beam system comprising a storage means for storing said N optical beams each read data of the first to N as the storage data of the first to N respectively, from the storage unit < br /> out read data stored in the first to N in a predetermined order communicated
The optical pickup follows the optical pickup so as to continuously output and read data of a second track group consisting of N tracks next to the first track group after reading of the first track group is completed. It is provided with read timing control means for controlling.

The reading method of the optical disk apparatus according to the present invention comprises an optical pickup for simultaneously reading data of a first track group consisting of the plurality of tracks on the optical disk by using a plurality of light beams, in reading method for an optical disc apparatus of a multi-beam system that stores light beam of each of the read data as respective storage data sequentially outputs these plurality of stored data read out continuously the plurality of stored data in a predetermined order to read the first track group outputs after completion continuously the first
A second track group consisting of the plurality of tracks following the track group of
The optical pickup is controlled so as to follow the data of the track group.

[0015]

FIG. 1 is a block diagram showing an embodiment of the present invention, in which components common to those in FIG. 4 are denoted by common reference characters / numbers. The optical disk device of the present invention has the same IV as the conventional first optical disk device.
Conversion circuits 11, 12, 14;
In addition to the amplification / demodulation circuit 21, the PLL 22, the focus servo circuit 15, and the tracking servo 16, the detectors 101, 102, 1 which are photoelectric conversion elements corresponding to each of the four beams instead of the photo detector 100
A photodetector 10 composed of the photodetectors 03 and 104, an IV conversion circuit 13 corresponding to the detector 103, and an IV conversion circuit 1
Amplifying / demodulating circuits 19, 23, 25 and PLLs 20, 24, 26 for amplifying and demodulating the output signals D1D3, D4 of the respective 1, 13, 14 and the write clocks CW1 to CW.
4, storage circuits 28 to 31 for storing output data DO1 to DO4 of amplification and demodulation circuits 19, 21, 23, and 25 in response to read clocks CR1 to CR4 and outputting data M1 to M4 in response to read clocks CR1 to CR4, respectively. Read switching circuit 32 which sequentially switches data M1 to M4 in response to supply of data switching signal SD and outputs the data as data DM, and write clocks CW1 to CW4, read clocks CR1 to CR4, data switching signal SD and other components. And a timing control circuit 27 that supplies a timing control signal of

Next, the operation of the present embodiment will be described with reference to FIG. 1. First, a method of outputting a multi-beam using a laser array composed of a plurality of lasers described in Japanese Patent Application Laid-Open No. 614-11744, Optical Engineering, 2nd
Vol. 2, No. 4, July / August 1983, 462-472
Information is read from an optical disk by irradiating four light beams by a known means such as a method of converting a read beam described on a page into a multi-beam by a diffraction grating, and a photodetector 10.
To convert it into an electric signal.

As in the above-described conventional optical disk apparatus, the output signals of the detectors 101 to 104 are IV-converted by IV converters 11 to 14, respectively, and the signal a = D
1, b to e, f = D3, and g = D4 are output. The operation circuit 17 responds to the supply of the signals b to e from the IV conversion circuits 121 to 124 by b + c + d + e = D2, (b +
d)-(c + e) = TA, (b + e)-(c + d) = F
Is performed. The arithmetic circuit 18 performs an arithmetic operation of ag = TB in response to the supply of the output signals a and g of the I / V conversion circuits 11 and 14, respectively. The signals TA and TB are supplied to the tracking servo circuit 16 and the signal F is supplied to the focus servo circuit 15, and are used for tracking control and focus control, respectively.

Each of the signals D1 to D4 is supplied to each of the amplification / demodulation circuits 19, 21, 23, 25 and the PLL 20,
22, 24, and 26. Amplification demodulation circuit 1
9, 21, 23, and 25 demodulate these signals D1 to D4, respectively, and output digital data DO1 to DO4. On the other hand, each of the PLL PLLs 20, 22, 24, and 26 generates demodulated clocks CP1 to CP4 in response to the supply of the signals D1 to D4, respectively, and amplifies and demodulates the corresponding amplifying / demodulating circuits 19, 21, 23, and 25 and the timing control circuit 27, respectively. To supply.

Each of data DO1 to DO4 is supplied to storage circuits 28 to 31, respectively. Each of the storage circuits 28 to 31 receives the write clock C from the timing control circuit 27.
In response to the supply of W1-CW4, these data DO1-D
O4 is captured and stored. Storage circuits 28 to 31
In response to the supply of read clocks CR1 to CR4, read data M1 to M4 corresponding to storage data DO1 to DO4.
Are output to the read switching circuit 32. At the same time, the timing control circuit 27 detects the memory circuit currently being read, generates a data switching signal SD corresponding to the memory circuit being read, and supplies the data switching signal SD to the read switching circuit 32, as described later. In response to the supply of the data switching signal SD, the read switching circuit 32 sequentially switches the corresponding read data M1 to M4 and outputs the data as data DM.

The timing control circuit 27 generates an optical pickup movement signal LM to generate the tracking servo circuit 1.
6 and the optical pickup is moved so that the next track information can be read at an appropriate timing.

Next, the operation of the timing control circuit 27 will be described with reference to FIG. 2, which is a time chart showing the operation state of each part of the timing control circuit 27. It is assumed that each beam of the multi-beam is traced at intervals of one track, that is, in this embodiment, the first to fourth tracks are traced by the first to fourth beams.

At the first rotation of the optical disk, data DO1 to DO4 for four tracks at a time are read using four beams and stored in the storage circuits 28 to 31, respectively.
At this time, the timing control circuit 27 stores the leading data of the data DO2 to DO4 of each of the second to fourth tracks, and stores the data at the end of reading the data DO1, that is, the final data, as the leading data of the data DO2 and the leading data of the data DO2. The last data is the top data of data DO3 and the data D
A comparison is made as to whether the last data of O3 matches the first data of data DO4. When it is determined that each track has been read correctly by detecting a match in all comparison results, the final data of the data DO4 is stored.

Next, at the second rotation of the optical disk, the optical pickup is moved to read the next fifth track. The data DO4 stored at that time is compared with the last data of the fourth track, and reading is started again from the next data in which the coincidence with the last data is detected, as in the case of the first track.

Thereafter, the operation of reading data DOi (i is an integer of 1 to 4) into the storage circuit and moving the optical pickup are alternately repeated.

As for the output of the data DM, the data M1 is converted into the data D at the double speed at the time when the data is written from the storage circuit 28 at the time when a half rotation, that is, one track is read to half.
Start outputting as M. When all the data M1 in the storage circuit 28 has been read, the next data M2 in the storage circuit 29 starts to be output as data DM. Thereafter, the same process is repeated to continuously output the data M1 to M4 as data DM.

Next, referring to FIG. 3, which is a block diagram showing an example of the configuration of the timing control circuit 27, the timing control circuit 27 includes a data storage circuit 51 for storing the leading data DH1 to DH4 of the data DO1 to DO4. ~ 5
4, data storage circuit 55 for storing final data DT4 of data DO4, final data DT1 and data DH2 of data DO1, final data DT2 and data DH3 of data DO2, and final data DT3 and data D of data DO3.
H4 and comparison circuits 56 to 59 for comparing the respective data DH1 and DT4 and outputting match signals C1 to C3 and a data read start signal RS, respectively;
An AND circuit 60 that takes the logical product of C3 and outputs a data read end signal RE; and generates an optical pickup movement signal LM in response to the supply of the signal RE, and stops generation of the signal LM in response to the supply of the signal RS. Optical pickup control circuit 61
And demodulated clocks CP1 to CP4 and signals RS, RE
, A write clock control circuit 62 that generates write clocks CW1 to CW4 in response to the supply of a clock signal, a multiplying circuit 63 that doubles the clock CP2 to generate a multiplied clock CM, and a multiplied clock CM and signals X1 to X4. A read clock control circuit 64 which receives the supply and generates read clocks CR1 to CR4 and a data switching signal SD; data M1, DH2,
Data M2, DH3, data M3, DH4, data M
4 and DH1 are compared with each other, and the corresponding coincidence signals X1 to X
4 which respectively generate comparison circuits 65 to 68.

The operation will be described. First, in the case of writing the demodulated data DO1 to DO4 into the storage circuits 28 to 31, first data DH1 to DH1 of these data DO1 to DO4 are written.
DH4 is stored in the data storage circuits 51 to 54, respectively. Next, the data DO1 on the first track and the head data DH2 on the second track are supplied to a comparison circuit 56 for comparison. The comparison circuit 56 outputs the final data DT1 of the data DO1.
When the data and the data DH2 match, it is determined that the data DO1 has been read up to the end point, and a match signal C1 is output. Similarly, each of comparison circuits 57 and 58 respectively has data DT
2, DH3 and data DT3, DH4, and outputs match signals C2, C3. The AND circuit 60 responds to the supply of the coincidence signals C1 to C3 to output the data DO1 to D0.
These signals C1 indicate whether all of O4 has reached the end point.
The determination is made based on the output of the logical product of .about.C3, and the data read end signal RE is output.

On the other hand, the data DO4 of the fourth track is also supplied to the data storage circuit 55, and stores the final data DT4 in response to the supply of the signal RE.

The final data DT4 read from the data storage circuit 55 is supplied to the comparison circuit 59 together with the demodulated data DO1 of the first track during the optical pickup moving operation. The comparison circuit 59 outputs a data read start signal RS when detecting the coincidence of the data DT4 and DO1. The data read start signal RS is transmitted to the data storage circuits 51 to 54
And demodulated data DO1 to DO4
To start reading.

The data read start signal RS and the data read end signal RE are supplied to an optical pickup control circuit 61 and a write clock control circuit 62, respectively.

The optical pickup control circuit 61 moves the optical pickup to the next track to be read from the time when the supplied data read end signal RE becomes valid until the data read start signal RS becomes valid. Thus, the optical pickup movement control signal LM is sent to the tracking servo.

The write clock control circuit 62 outputs each of the demodulated clocks CP1 to CP4 as write clocks CW1 to CW4 until the data read start signal RS becomes valid and the data read end signal RE becomes valid. I do.

Next, the data M1 to M1 are stored in the storage circuits 28 to 31.
When reading M4, demodulation clocks CP1 to CP
Any one of P4, in this embodiment, CP2 is multiplied by a multiplying circuit 63 to a double frequency to generate a multiplied clock CM, which is supplied to a read clock control circuit 64. The read clock control circuit 64 is controlled as follows. The comparison circuit 65 compares the data M1 currently being read and the data DH2, and outputs no coincidence signal X1 (invalid state) as the read clock CR1 during a period in which the data M1 and the data DH2 do not match. When they match, the match signal X1 is output, that is, the state becomes valid, the multiplied clock CM is output as the read clock CR2, and the data switching signal SD is switched to switch the data M1 currently being read to the data M2 to the data D2.
Output as M. Similarly, the comparison circuit 6 compares each of the data M2, M3, M4 currently being read and each of the head data DH3, DH4, DH1 corresponding to the next read track.
6, 67, 68, and match signals X2, X3, X
4 are sequentially enabled, and the first data DH3, DH4, D
Each data storage circuit 53, 54, 51 storing H1
Read clocks CR3, CR4, and CR1 are sequentially generated.

As described above, in the optical disk apparatus of the present embodiment, the read data corresponding to each of the multi-beams is successively output sequentially. Since data transfer is not interrupted, high-speed data output can be performed without impairing the smoothness of motion of moving images or interrupting sound. Although the instantaneous data transfer speed is lower than that of the conventional multi-beam system, the average data transfer speed is the same.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made. For example, instead of setting the number of light beams to four and reading at double speed, reading and reading at an appropriate speed by appropriately increasing or decreasing the number of light beams can be applied without departing from the gist of the present invention. Of course. Further, instead of tracing the track interval of each beam for one track, that is, tracing each adjacent track, it is also possible to set the above-mentioned interval to two tracks or three tracks according to the memory capacity of the storage circuit and the like. Further, in the case of an audio optical disk or the like in which the data transfer speed needs to be kept the same as in the past, applications such as lowering the rotation speed of the optical disk are possible.

[0036]

As described above, according to the present invention, an optical disc apparatus and a reading method of the present invention, own the plurality of stored data
Providing the read timing control means for tracking controls the optical pickup to read data of the first group of tracks of the reading end after second track group to the next successive outputs the read out continuously in a fixed order This enables high-speed output at the frequency ratio of the read clock to the demodulated clock without increasing the number of rotations of the disk, and eliminates deterioration factors such as interruption of temporally continuous data such as moving images and audio signals. This has the effect of enabling high quality reproduction.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of an optical disk device of the present invention.

FIG. 2 is a time chart illustrating a reading method of the optical disc device of the present embodiment.

FIG. 3 is a block diagram illustrating a configuration of a timing control circuit of FIG. 1;

FIG. 4 is a block diagram showing an example of a first conventional optical disk device.

FIG. 5 is a time chart showing a reading method of a conventional optical disk device.

FIG. 6 is a block diagram showing an example of a second conventional optical disk device.

[Explanation of symbols]

10, 100, 110 Photodetectors 11 to 14, 121 to 124, 12A to 12D I /
V conversion circuit 15 Focus servo circuit 16 Tracking servo circuit 17, 18, 171, 172 Operation circuit 19, 21, 23, 25 Amplification / demodulation circuit 20, 22, 24, 26 PLL circuit 27 Timing control circuit 28-31 Storage circuit 32 Reading Switching circuit 51-55 Data storage circuit 56-59, 65-68 Comparison circuit 60 AND circuit 61 Optical pickup control circuit 62 Write clock control circuit 63 Multiplication circuit 64 Read clock control circuit

Claims (4)

(57) [Claims] 1. An optical pickup for simultaneously reading data of a first track group consisting of N tracks on an optical disk using N (N is an integer) light beams, and each of the N light beams A multi-beam type optical disc apparatus comprising: a storage unit for storing first to N-th read data as first to N-th storage data, respectively ; the data of the second group of tracks consisting of next N tracks of the first reading after completion continuously track group the first group of tracks and outputs <br/> read out continuously in order optical disc apparatus according to feature in that it comprises a read timing control means for tracking controls the optical pickup to read. 2. The first read-out control means for storing first data of each of the first to N-th tracks.
To N-th head data storage means; last data storage means for storing last data of the N-th track; and last data of each of the first to N-th storage data of the first track group. First to Nth comparison circuits for detecting respective inconsistencies of the second to Nth and first head data of the second track group and outputting first to Nth inconsistency signals; In response to the supply of each of the first to Nth mismatch signals, the first to Nth readouts of each of the first to Nth storage data are performed.
A read clock control circuit for generating a read clock of the second track group; detecting a match between the last data of the first track group and the first head data of the second track group; A track data comparing means for generating a data read start signal for instructing a data read start; and a match between each of the last data of the first to Nth storage data and each of the second to Nth head data. And a first to (N-1) th track end detecting means for detecting each of the first to (N-1) th track end signals, and performing an AND operation on the first to (N-1) th track end signals An AND circuit for generating a data read end signal for the first track group; and generating an optical pickup control signal for follow-up control of the optical pickup in response to the supply of the data read end signal. 2. The optical disk apparatus according to claim 1, further comprising: an optical pickup control unit that stops the optical pickup control signal in response to a supply of a reading start signal. 3. An optical pickup for simultaneously reading data of a first track group consisting of a plurality of tracks on an optical disk using a plurality of light beams, wherein read data of each of the plurality of light beams is read. in stored as each of the stored data readout method of the optical disc apparatus of a multi-beam system for sequentially outputting these plurality of stored data continuously <br/> outputs read out in a predetermined order the plurality of stored data At the same time, after the reading of the first track group is completed, the optical pickup is controlled so as to read data of a second track group consisting of the plurality of tracks following the first track group. A reading method for an optical disk device, comprising: 4. An optical pickup follow-up operation period for controlling the movement of the optical pickup to a reading position corresponding to the second track group during a read stop period after reading of the plurality of storage data of the first track group is completed. 4. The method for reading an optical disk device according to claim 3, further comprising: