JP3885360B2 - Optical disk playback device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical disk reproducing apparatus that reads and reproduces information for a plurality of tracks recorded on a disk at a time.
[0002]
[Prior art]
The prior art will be described using an optical disc as an example. In recent years, it has been planned to record and reproduce a high-definition television signal on an optical disc using a digital signal. One of the characteristics of this signal is that the amount of signal to be transferred per time is 50 Mbps (bps is a unit representing the information transfer amount (bit) per second), and the transfer amount of the compact disc currently used. It is extremely high, about 40 times (1.2 Mbps), and a relatively high information transfer rate is required.
[0003]
Here, as a conventional optical disk information reproduction form, there is an apparatus for recording / reproducing information on, for example, a phase change type optical disk D as shown in FIG. In FIG. 3, the light emitted from the laser diode 1 is converted into parallel light by the collimator lens 2. The parallel light passes through the beam splitter 3 and is focused on the disk D by the objective lens 4. Reflected light from the disk D passes through the objective lens 4 to become parallel light, is reflected by the beam splitter 3, and enters the cylindrical lens 5. The light that has caused astigmatism by the cylindrical lens 5 enters the photodetector 6, and a tracking signal, a focus signal, and an information signal are obtained from the photodetector 6.
[0004]
Under such a conventional configuration, information is recorded in a single spiral using one recording light beam from the inner periphery, and the recorded spiral track is read and reproduced by one reproducing light beam. The action of going is performed. At this time, it is common practice to use three beams for control to trace one track, but even with this configuration, only one light beam is used to reproduce information. Only the recording information of one track was read out.
[0005]
When recording information in a single spiral with such a single beam, in order to increase the transfer rate, it is necessary to use a method of increasing the information density to be read by increasing the rotational speed of the disk D. In order to realize this method, it is necessary to increase the output of the laser diode 1 or increase the recording sensitivity of the disk D as a recording medium.
[0006]
Further, in order to read disc recorded information, it is necessary to cause the objective lens 4 to accurately follow the surface shake of the disc D at a high frequency, or to shorten the reading wavelength and increase the information density. Above all, since it is necessary to always rotate the disk D at a high speed during recording and reproduction, problems of high noise, high vibration, and high power consumption occur as the transfer rate increases.
[0007]
On the other hand, there are a technique described in JP-A-5-135403, a technique described in JP-A-6-231473, and a technique described in JP-A-8-249720. These methods irradiate a linear light beam, multiple light spots, or wide area illumination onto multiple adjacent tracks on the disk to record or read information on multiple tracks simultaneously. To improve the transfer rate.
[0008]
FIG. 4 is a block diagram showing an example of the configuration of a conventional optical disc reproducing apparatus of this type. The prior art relating to simultaneous readout of information signals from a plurality of tracks by a plurality of spots will be described in detail with reference to FIG.
[0009]
In FIG. 4, a semiconductor laser light source 21 generates laser light for reading with respect to an optical disk 20 recorded with a single spiral track structure. This laser beam is divided into three by the diffraction grating 22 and guided to the beam splitter 23. The beam splitter 23 guides each of the split lights from the diffraction grating 22 to the objective lens 24 as a read beam.
[0010]
The objective lens 24 irradiates the three lights incident from the beam splitter 23 to the spots A, B, and C as reading points on the optical disk 20 and extends over the three tracks. Each spot light, that is, the read beams A, B, and C is reflected in accordance with the state of the recording surface of the disk 20 and guided to the photodetectors 25, 26, and 27 through the objective lens 24 and the beam splitter 23.
[0011]
These photodetectors 25, 26, and 27 receive the incident light from the beam splitter 23 for each spot light, and detect the received light intensity, that is, the reflected light intensity from the disk 20. The detection outputs of the photodetectors 25, 26, and 27 are supplied as reflected light intensity detection signals to the first-stage demodulators 31, 32, and 33, respectively. These first stage demodulators 31, 32, 33 demodulate the reflected light intensity detection signal by binarizing it and transfer it to the memories 34, 35, 36 as read data. Each memory writes the transferred read data under the control of the write address controller 41, and then outputs the read data to the selector 37 under the control of the read address controller 43.
[0012]
The selector 37 selectively outputs one of the read data read from the memories 34, 35, 36 to the final demodulator 38 in accordance with a selection control signal from the CPU 42. Therefore, the data read out at the same time for three tracks is edited and input to the final demodulator 38 as one continuous data. The final demodulator 38 performs a demodulation process so that the read data sequentially matches an information output system (not shown).
[0013]
Here, in the optical disc 20, a single spiral track is formed so as to advance from the inside to the outside, while the CPU 42 causes the reading beam position to jump to the outer circumferential direction at a certain interval. Thus, the recording information from the three tracks in the radial direction can be efficiently captured at the same time by the three reading beams.
[0014]
FIG. 2 shows the relationship between the number of sectors of the information signal obtained as described above and the time from the end of seeking at a certain radial position, and the characteristic line A in the figure is the characteristic of this example.
[0015]
As is apparent from the characteristic line A, in the optical disk reproducing apparatus having the conventional configuration, the signals simultaneously read every three tracks are converted into a single spiral series signal by making full use of the read address controller 43 and the selector 37. Data are connected so as to correspond to each other, and are sent to the final demodulator 38 as a signal corresponding to a single spiral signal. Therefore, it can be seen that the slope of the characteristic line A is larger than that of the characteristic line B when information of one track is sequentially read with one beam, and the information transfer rate is improved.
[0016]
[Problems to be solved by the invention]
A conventional optical disk reproducing apparatus that reads the recording information of a plurality of tracks on the disk 20 as described above and demodulates the read signals by connecting the data so as to correspond to a single spiral series of signals. Then, initially, the optical disc 20 was read during one rotation, that is, for several tens to several hundreds of milliseconds from 0 to T0a seconds in FIG. Since the signals are not connected in series, the data connected to the final demodulator 38 cannot be sent, and there is a problem that the demodulated signal cannot be sent. Therefore, at the beginning of the reading operation after the end of the seek operation, the read signal cannot be reproduced for several tens to several hundreds of milliseconds, and a large number of information with a small number of continuous sectors is read. The characteristic line B in FIG. 2 has a problem in that the readout time becomes longer compared to the case of readout in the case of readout from 0 to T0a seconds).
[0017]
Such a problem naturally occurs not only in an optical disk reproducing apparatus but also in a magnetic disk reproducing apparatus configured to simultaneously read recorded information from a plurality of tracks of a magnetic disk by a plurality of magnetic heads.
[0018]
The present invention has been made in order to solve the above-described conventional problems. The object of the present invention is to obtain a high information transfer rate by reading and reproducing recorded information of a plurality of tracks at a time and continuously. It is an object of the present invention to provide an optical disc reproducing apparatus capable of outputting a reproduction signal in a short time without waiting even when reading information with a small number of sectors.
[0019]
[Means for Solving the Problems]
In order to achieve the above object, a feature of the first invention is an optical disc having a configuration in which a recording beam is simultaneously read and reproduced by irradiating the optical disc with a light beam so as to extend over a plurality of tracks in the radial direction of the optical disc. A reproducing apparatus, a position detecting unit for detecting a position where the light beam is irradiated on the optical disc, and a case in which recorded information is read out for each track based on the position information detected by the position detecting unit. Calculating means for obtaining a reference amount of information in which the reading time when reading recorded information for each of a plurality of tracks is substantially the same, and a reference information amount calculated by the calculating means According to the comparison result of the comparison means, a reproduction start time for reproducing the recorded information for each track, and a plurality of If there is a difference between the reproduction start time for reproducing the recorded information for each rack, in that a switching control means for switching on the side to reproduce the recorded information in each track.
[0020]
According to the first aspect of the present invention, when reading a plurality of tracks at a time, at the beginning of reading, the read information from each read track cannot be connected and continuous until the optical disk rotates once. The read information is not reproduced and not output. Accordingly, when the number of sectors to be read is equal to or less than the reference sector amount, if a method of reading the recording information of a plurality of tracks at a time is employed, a waiting time is generated until a reproduction signal is output. The method of reading the record information every time can read the information in a shorter time. Therefore, the amount of sectors to be read is compared with the reference sector amount, and if the sector amount to be read is smaller than the reference sector amount, information is reproduced by a method of reading recorded information for each track. When the amount is larger than the reference sector amount, switching is performed so that the information is reproduced by a method of reading the recording information for every plurality of tracks. At this time, when information is recorded on the optical disc at a constant linear velocity, the reference sector amount differs depending on the reading position on the optical disc, so the reference sector amount is obtained according to the position.
[0021]
According to a second aspect of the invention, there is provided an optical disk reproducing apparatus having a configuration in which a recording beam is simultaneously read and reproduced by irradiating a light beam on the optical disk so as to extend over a plurality of tracks in the radial direction of the optical disk. A storage means for storing in advance a reference information amount in which the read time for reading the record information every time and the read time for simultaneously reading the record information for each of the plurality of tracks are substantially the same; The comparison means for comparing the reference information amount, and the difference between the reproduction start time for reproducing the recorded information for each track and the reproduction start time for reproducing the recorded information for a plurality of tracks according to the comparison result of the comparison means. If there is, there is provided switching control means for switching to the side for reproducing the recorded information for each track.
[0022]
According to the second aspect of the invention, the amount of sectors to be read is compared with the reference sector amount, and if the sector amount to be read is smaller than the reference sector amount, the information is reproduced by reading the recorded information for each track. When the sector amount to be read is larger than the reference sector amount, switching is performed so that the information is reproduced by a method of reading the recording information for each of a plurality of tracks. At this time, when information is recorded on the optical disc at a constant angular velocity, the reference sector amount is constant because it does not change depending on the reading position on the optical disc.
[0023]
The characteristic of the light applied to the optical disk of the third invention is any of a plurality of spot lights, linear lights, or wide area illumination.
[0024]
According to the third aspect of the invention, the plurality of spot lights are irradiated onto the plurality of tracks on the optical disc in the radial direction, and the recorded information is read from the plurality of tracks. The linear light irradiates a plurality of tracks on the optical disk in the radial direction, and the recorded information is read from the plurality of tracks. The wide-area illumination includes a plurality of tracks in the radial direction on the optical disc, and recorded information is read from the plurality of tracks.
[0025]
The switching control means of the fourth invention is characterized in that a single light spot is applied to the optical disc and the recorded information is read and reproduced for each track, or a plurality of tracks are applied to the optical disc by applying a plurality of light spots. It is to switch whether to read out and reproduce the recorded information every time.
[0026]
According to the fourth aspect of the invention, when recording information is reproduced for each track, a single light spot is applied to the optical disk, while when recording information is reproduced for a plurality of tracks, a plurality of light spots are used. Are switched to simultaneously apply to the plurality of tracks.
[0027]
The switching control means of the fifth invention is characterized in that the recording information is always read out for each of the plurality of tracks and the signal for one track is reproduced and output, or the signals of the plurality of tracks are made continuous signals. It is to switch between editing and output.
[0028]
According to the fifth aspect of the invention, when recording information is always read from a plurality of tracks on the optical disc at the same time by a plurality of spots or by linear light or wide area illumination, and the recording information is reproduced for each track, When paying attention to one demodulated reproduction signal of a plurality of read tracks and outputting the one system demodulated reproduction signal as it is, while reproducing recorded information for each of a plurality of tracks, the read plural The demodulated reproduction signals of all systems of the track are temporarily stored in a memory or the like, and then are switched to one signal in a continuous manner.
[0029]
According to a sixth aspect of the present invention, the switching control means switches between applying a single light spot to the optical disc or applying a plurality of light spots to the optical disc and reproducing a signal for one track. It is to switch both of the output or the reading of the signals of a plurality of tracks, editing the signals into continuous signals and outputting them.
[0030]
According to a seventh aspect of the present invention, the switching control means switches whether the recorded information is read and reproduced for each track or whether the recorded information is read and reproduced for each of the plurality of tracks, and the rotation speed of the optical disk is switched. There is.
[0031]
According to the seventh aspect of the invention, for example, when recording information is read and reproduced for each track, if the rotational speed of the optical disk is made faster than usual, the information transfer rate can be increased accordingly.
[0032]
The feature of the position detecting means of the eighth invention is that, when a plurality of light spots hit the optical disk, the position on the optical disk of at least one light spot is detected.
[0033]
By the way, the present invention described above has been described with respect to the optical disk reproducing apparatus. However, this configuration can be directly applied to the magnetic disk reproducing apparatus. That is, an apparatus that reads and reproduces recorded information on a magnetic disk by a plurality of magnetic heads, and has both a function of reproducing recorded information for each track on the magnetic disk and a function of reproducing recorded information for each track. In the disk reproducing apparatus, a position detecting unit for detecting the position of the magnetic head on the magnetic disk, and a case where a plurality of tracks are read out on the basis of the position information detected by the position detecting unit. Calculating means for obtaining a reference sector amount for which the reading time is the same when reading recorded information every time, a comparing means for comparing the sector amount to be read from the reference sector amount calculated by the calculating means, and the comparing means Whether the recorded information is reproduced for each track or the recorded information is reproduced for a plurality of tracks according to the comparison result In that a switching control means for switching.
[0034]
In addition, the recording information on the magnetic disk is read and reproduced by the magnetic head. The recording information is reproduced for each track on the magnetic disk in the radial direction of the magnetic disk. In a magnetic disk reproducing apparatus having both functions of reading and reproducing, a memory for previously storing a reference sector amount in which the reading time is the same when reading recorded information for each track and reading recorded information for a plurality of tracks Means, a comparing means for comparing the sector amount to be read out with the reference sector amount of the storage means, and reproducing the recorded information for each track or recording information for each track according to the comparison result of the comparing means. Switching control means for switching whether to reproduce.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of an optical disk reproducing apparatus according to the present invention. However, the same parts as those of the conventional example shown in FIG. The optical disk reproducing apparatus includes a semiconductor laser light source 21 that generates a reading laser, a diffraction grating 22 that divides the laser light into three beams, a beam splitter 23 that separates incident light and reflected light, and three-beam laser light into the optical disk 20. Objective lens 24 condensing on the surface, 3 beams of laser reflected light received and detected by photodetectors 25, 26 and 27, and reflected light intensity detection signals of photodetectors 25, 26 and 27 are binarized and demodulated. The first-stage demodulator 31, 32, 33, and the output of the first-stage demodulator 31 are sent to the memory 34 side or to the final-stage demodulator 38. The demodulated signal branching unit 39 switches the data to the memories 34, 35, 36. A write address controller 41 that performs write control, a read address controller 43 that performs read control of data from the memories 34, 35, and 36, and memories 34 and 3 , 36 for selecting one of the read signals, a final demodulator 38 for demodulating the read signal selected by the selector 37 so as to match the information output system, a write address controller 41, a read address controller 43 selector 37 and the beam movement control circuit 44 as well as the CPU 42 for controlling the entire apparatus, the actuator 45 for moving the optical pickup system such as the objective lens 24, and the beam movement for moving the three beams A, B and C by operating the actuator 45. A control circuit 44 is provided.
[0036]
Next, the operation of the present embodiment will be described. The semiconductor laser light source 21 generates a laser beam for reading with respect to the optical disk 20 recorded with a single spiral track structure. This laser beam is divided into three by the diffraction grating 22 and guided to the beam splitter 23. The beam splitter 23 guides each of the split lights from the diffraction grating 22 to the objective lens 24 as a reading beam. The objective lens 24 irradiates the optical disk 20 by narrowing the three laser beams incident from the beam splitter 23 into spots as reading points A, B, and C on the optical disk 20.
[0037]
Each spot light, that is, the reading beams A, B, and C is reflected according to the state of the recording surface of the optical disc 20 and guided to the photodetectors 25, 26, and 27 through the objective lens 24 and the beam splitter 23. These photodetectors 25, 26, and 27 receive incident light from the beam splitter 23 for each spot light, and detect the received light intensity, that is, the reflected light intensity from the optical disk 20.
[0038]
The detection outputs of the photodetectors 25, 26, and 27 are supplied as reflected light intensity detection signals to the first-stage demodulators 33, 32, and 31, respectively. These first-stage demodulators 31, 32, and 33 demodulate the reflected light intensity detection signals by binarizing them into read data, and transfer these data to the memories 34, 35, and 36.
[0039]
Each memory 34, 35, 36 writes the transferred read data and then outputs the read data to the selector 37. The selector 37 selectively outputs one of the read data read from the memories 34, 35, 36 to the final demodulator 38 according to the selection control signal of the CPU 42. The final demodulator 38 performs demodulation processing so that the read data selected by the selector 37 sequentially matches an information output system (not shown).
[0040]
When reading from the optical disk 20 using three beams as described above, the CPU 42 switches the demodulated signal branching device 39 to the memory 34 side in advance.
[0041]
Each of the first-stage demodulators 31, 32, and 33 reads a signal necessary for connecting data such as a read address and a frame synchronization signal and detects it as a data combining control signal (or a read data combining index signal), This is supplied to the write address controller 41. The write address controller 41 sends such a coupling signal to the CPU 42. When the CPU 42 receives the coupling signal, the CPU 42 determines whether it is valid read data to be connected based on this, and if so, sets the write addresses of the memories 34, 35, 36 in the write address controller 41. A command signal is issued.
[0042]
Each of the memories 34, 35, and 36 sequentially writes the read data for the write address thus set. The CPU 42 performs memory read control together with the read address controller 43 in parallel with the above-described memory write control. If the CPU 42 determines that it is time to read, it issues a command signal to the read address controller 43 to set the read address. In response to a command signal issued from the CPU 42, the read address controller 43 reads one memory to be read out of the memories, and sequentially increments or decrements the address.
[0043]
Further, the CPU 42 supplies a selection control signal to the selector 37 in response to the above-described increment or decrement and in response to the activation timing. Therefore, the selector 37 selects the memory under read control. Eventually, the data simultaneously read from the three tracks of the optical disc 20 is temporarily held in the memories 34, 35 and 36, edited into one long data by the selector 37, and output to the final demodulator 38.
[0044]
The CPU 42 serving as a part of the reproduction control means generates a track jump pulse and supplies it to the beam movement control circuit 44. In response to the track jump signal, the beam movement control circuit 44 supplies a drive signal to the track king actuator 45 serving as means for moving the optical beam in the disk radial direction so that the track jump at the reading point due to the deviation of the objective lens 24 is performed. To do. Further, the position detector 46 in the radial direction of the optical disk 20 detects the position of at least one optical disk 20 in the circumferential direction of the light beam spot based on the read beam, and this is given to the CPU 42. As the position detector 46, for example, a circuit that obtains the detection output using a pulse synchronized with the rotation of the optical disc 20 by a method other than the above may be employed. The CPU 42 performs reproduction control based on the detection output as described above.
[0045]
Note that a system for transmitting information to the first-stage demodulator 31 and the memory 34 via the photodetector 27 constitutes a reading information capturing system for the reading beam A, and transmits information to the first-stage demodulator 32 and the memory 35 via the photodetector 26. The system constitutes a reading information capturing system for the reading beam B, and the system for transmitting information to the first-stage demodulator 33 and the memory 36 via the photodetector 25 constitutes a reading information capturing system for the reading beam C.
[0046]
Here, in the optical disc 20, a single spiral track is formed so as to advance from the inside to the outside, while the CPU 42 causes the reading beam position to jump to the outer circumferential direction at a certain interval. Thus, the recording information from the three tracks in the radial direction on the optical disc 20 can be efficiently captured by the three reading beams at the same time.
[0047]
In FIG. 2, the characteristic line B shows the number of sectors of the information signal and the time relationship from the end of seek when a single spiral series of signals is read out with a single light spot at a certain radial position of the optical disc 20. is there. On the other hand, the characteristic line A combines the data so that the signals for every three tracks correspond to a series of single spiral signals, and the final demodulator as a signal corresponding to the single spiral signals. 4 shows the number of sectors in the information signal when it is sent to 38 and the time relationship from the end of seek.
[0048]
In the characteristic line A, no information signal is transmitted from time 0 to time T0a in FIG. 2 due to the principle of signal demodulation. When the information signal is recorded on the optical disc 20 at a constant linear velocity, the time from 0 to T0a varies depending on the radial position of the light spot on the optical disc 20. It is assumed that the information signal is recorded on the optical disc 20 of this example at a constant linear velocity.
[0049]
When T0a is passed, the signal is read every three tracks, so that the information amount can be read three times as much as the characteristic line B in the same time. T0a is the reproduction start time of the information signal. The reproduction start time of the information signal related to the characteristic B is 0. As is apparent from FIG. 3, the time for reading the information on the number of sectors Sc is the same for both the single light spot and the signal read for every three tracks. However, when reading a relatively small amount of information with the number of sectors of S1, T1b <T1a, and it can be seen that it takes a shorter time to read data with a single spot. In addition, when reading a relatively large amount of information of the number of sectors in S2, T2a <T2b, and it can be seen that a shorter time is required when reading signals every three tracks.
[0050]
When the signal of the position detector 46 for detecting the position of the light spot on the optical disk 20 is input to the CPU 42, the CPU 42 can read out the signal by a single light spot or every three tracks based on this signal. An operation for obtaining the sector amount at the same time is performed. Let Sc be the sector amount thus obtained.
[0051]
Next, the CPU 42 compares the number of consecutive sectors Sr and Sc to be read out. In the case of Sr> Sc, the CPU 42 instructs each element shown in the figure to perform the reproducing operation by the three reading beam methods as described above. In the case of Sr = Sc, the read time is the same for the three read beam system playback operations and the single beam system playback operation, so the CPU 42 performs the three read beam system playback operations as described above. In order to instruct each element shown in the figure, or to perform a reproduction operation by a single-beam method, a signal is sent to a light beam number control circuit (not shown) and a demodulated signal branching unit 39, and a signal read by a single beam Is detected by the photodetector 27 and an instruction is issued to output the signal demodulated by the first demodulator 31 directly to the final demodulator 38.
[0052]
According to the present embodiment, when reproducing information of a large number of continuous sectors, the time from the end of seeking to the completion of reading is shorter than the data reading method using one beam, the data is read by the three beam method, The transfer rate can be improved. On the other hand, when reading an information amount having a relatively small number of sectors, data is read by the single-beam method, so that a waiting time during which data is not read can be eliminated and data can be read in the shortest time.
[0053]
Next, a second embodiment of the optical disk reproducing apparatus of the present invention will be described. However, since the configuration of this example is the same as that of the first embodiment shown in FIG. 1, the description will be made with reference to FIG. In this example, an information signal is recorded on the optical disc 20 at a constant angular velocity. When the information signal is recorded on the optical disc 20 at a constant angular velocity, Sc in FIG. 2 is constant regardless of the radial position of the optical spot on the optical disc 20, and therefore, regardless of the radial position of the optical spot on the optical disc 20, Since the time from 0 to T0a is constant, it is not necessary for the CPU 42 to calculate Sc by calculating the position of the light spot on the optical disc 20 one by one, and Sc is stored in advance in a memory (not shown).
[0054]
Therefore, the CPU 42 compares the Sc stored in the memory with the continuous sector number Sr to be read. In the case of Sr> Sc, the CPU 42 instructs each element shown in the figure to perform the reproducing operation by the three reading beam methods as described above. In the case of Sr = Sc, the read time is the same for the three read beam system playback operations and the single beam system playback operation, so the CPU 42 performs the three read beam system playback operations as described above. In order to instruct each element shown in the figure, or to perform a reproduction operation by a single-beam method, a signal is sent to a light beam number control circuit (not shown) and a demodulated signal branching unit 39, and a signal read by a single beam Is detected by the photodetector 27 and an instruction is issued to output the signal demodulated by the first demodulator 31 directly to the final demodulator 38. This embodiment also has the same effect as the first embodiment.
[0055]
In the first and second embodiments, the rotation speed of the optical disk 20 is assumed to be a normal speed. However, if the rotation speed of the optical disk 20 is increased, both the single-beam method and the three-beam method are used. The information transfer rate can be improved. It is also possible to increase the information transfer rate of the single-beam method by increasing the rotation speed of the optical disk 20 only when switching to the single-beam method.
[0056]
In the first and second embodiments, the case where three light beams are used has been described. However, the number of light beams used for reproduction is not three light beams, for example, a plurality of light beams are long in the radial direction of the optical disc 20. Information reading means for the photodetectors 25, 26, 27 and the first-stage demodulators 31, 32, 33 and thereafter using a rectangular light beam (linear light) capable of irradiating the radial position of the light and a wide range of irradiation light The same effect can be obtained by controlling the number of.
[0057]
Furthermore, in the first and second embodiments described above, the case where three tracks of data are read at once using three light beams has been described, but two or more tracks are used using two or more light beams. The same effect can be obtained by applying the present invention even when data is read at a time.
[0058]
In the first and second embodiments, the case where both the number of light beams and the number of read information fetching means are controlled has been described. However, the same effect can be obtained by controlling either one of the numbers. Can be obtained.
[0059]
By the way, the case where the above-described invention is applied to an apparatus for reproducing data from an optical disk using a three-beam optical pickup has been described, but a configuration in which data is simultaneously read from three tracks of a magnetic disk using three magnetic heads. The same effect can be obtained by applying the present invention to this device.
[0060]
【The invention's effect】
As described above in detail, according to the optical disk reproducing apparatus of the present invention, it is possible to obtain a high information transfer rate by reading and reproducing the recording information of a plurality of tracks at a time, and to record information with a small number of continuous sectors. Even in reading, a reproduction signal can be output in a short time.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a first embodiment of an optical disk reproducing apparatus according to the present invention.
FIG. 2 is a characteristic diagram showing the number of sectors of the information signal obtained at a certain radial position on the optical disc and the time relationship from the end of seek.
FIG. 3 is a block diagram showing an example of a schematic configuration of a conventional optical disc recording / reproducing system.
FIG. 4 is a block diagram showing a configuration example of a conventional optical disc playback apparatus.
[Explanation of symbols]
20 Optical disc
21 Semiconductor laser light source
22 Diffraction grating
23 Beam splitter
24 Objective lens
25, 26, 27 Photodetector
31, 32, 33 First stage demodulator
34, 35, 36 memory
37 selector
38 Final demodulator
39 Demodulation signal splitter
41 Write address controller
42 CPU
43 Read address controller
44 Beam movement control circuit
45 Actuator
46 Position detector

Claims (2)

Detection by irradiating a light beam so as to straddle a plurality of adjacent tracks on a spirally formed optical disk, and recording information pre-recorded on each track is detected by a separate photodetector corresponding to each track The output is recorded in a separate memory and a recording data reproducing system having a final demodulator, and the recording data recorded on each track is simultaneously read into the separate memory. Read data from the optical disc after the recording data stored in each of the memories is serialized by the continuous reading and the continuous reading, and then the track to the next arbitrary plurality of tracks An optical disk playback device for playing back an optical disk by jumping,
Position detecting means for detecting a position at which the light beam is irradiated on the optical disc;
Based on the position information detected by the position detection means, a read time until the record information is continuously read out to the final demodulator by a single photodetector regardless of the record data reproduction system, and Calculating means for obtaining a reference amount of information for which recording information is simultaneously read out for each of a plurality of tracks by a recording data reproducing system and the reading time from the recording data reproducing system to reading out to the final demodulator is substantially the same; ,
A comparison means for comparing the amount of information to be read from the reference information amount calculated by the calculation means;
According to the comparison result of the comparison means, the switching control means for switching to the side for reproducing the record information on a single track when the record information is reproduced on a single track is faster than reproducing the record information for each of a plurality of tracks. An optical disc reproducing apparatus comprising: Detection by irradiating a light beam so as to straddle a plurality of adjacent tracks on a spirally formed optical disk, and recording information pre-recorded on each track is detected by a separate photodetector corresponding to each track The output is recorded in a separate memory and a recording data reproducing system having a final demodulator, and the recording data recorded on each track is simultaneously read into the separate memory. Read data from the optical disc after the recording data stored in each of the memories is serialized by the continuous reading and the continuous reading, and then the track to the next arbitrary plurality of tracks An optical disk playback device for playing back an optical disk by jumping,
Read time until the recording information is continuously read out to the final demodulator regardless of the recording data reproducing system with a single photodetector, and the recording information is simultaneously read out for each of a plurality of tracks by the recording data reproducing system, Storage means for preliminarily storing a reference information amount that is substantially the same as the read time until reading to the final demodulator through the recorded data reproduction system;
Comparison means for comparing the amount of information to be read from the reference information amount of the storage means;
According to the comparison result of the comparison means, the switching control means for switching to the side for reproducing the record information on a single track when the stored information is reproduced on a single track is faster than the reproduction of the record information on a plurality of tracks. An optical disc reproducing apparatus comprising:

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