JPH05314503A - Device and medium for recording information and method for recording and reproducing information - Google Patents

Abstract

PURPOSE:To obtain an information recorder shortening in particular a retrieval time seeking out required information optically and quickening effectively information retrieval, and a recording medium recorded by the device, and an information recording and reproducing method using the medium. CONSTITUTION:This device is the information recorder provided with the information recording medium, an optical system radiating an information recording and reproducing beam on the information recording medium, and the optical system is provided with an objective lens 54 radiating the beam 51 on the information recording medium 55, a movable optical system 67 forming integrally a means 53 deflecting the beam and a means being made parallel luminous flux to enter the movable optical system 67. Further, the recording medium is divided to the blocks of a nearly concentric circle shape constituted of plural tracks and the track has an identification signal for being identified in each block.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording apparatus, an information recording medium, and an information recording / reproducing method, and more particularly, to accurately read desired information on a recording medium such as video and audio signals or computer data. The present invention relates to an information recording apparatus, an information recording medium, and an information recording / reproducing method suitable for recording at high density so that they can be output.

[0002]

2. Description of the Related Art Conventionally, information such as a video signal and computer data is modulated in a binary form and recorded on a recording medium on a disc, for example, in a non-contact manner, in a high density asperity, or in a light and shade form and There is known an information retrieval device that reproduces desired information accurately without contact using an irradiation beam such as a beam. In such an information retrieval device, from the information recorded at high density, the information groove in which the necessary information is recorded is detected, and the irradiation beam is moved to the above position,
It is necessary to accurately retrieve and reproduce only the necessary information.

As a solution to this problem, when reproducing a disc in which information grooves in which information is recorded are concentrically recorded on the disc, conventionally, at the time of recording, as described in detail in JP-A-49-68614. A signal indicating the order of the information grooves is inserted into one portion (within the vertical blanking period) of one information groove corresponding to one frame of the television image, and the light beam is moved to the vicinity of the desired information groove at the time of reproduction, and the desired information groove is obtained. A signal indicating the order of the information grooves is reproduced by reproducing the information recorded in the information grooves by performing drawing to position the light beam in one information groove near the information grooves and then performing tracking for tracking the information grooves. This is a method of detecting the deviation from the desired information groove and moving the light beam to the information groove in which the desired information is recorded.

[0004]

However, in order to find the desired information groove, this method must at least once track an information groove different from the desired information groove and detect a signal indicating the order. Therefore, it takes a very long time to reproduce the information from the desired information groove.

Therefore, an object of the present invention is to eliminate the above-mentioned problems in searching for desired information,
The first purpose is an improved information recording apparatus, the second purpose is an information recording medium recorded thereby, and the third is.
The purpose of is to provide an information recording / reproducing method using the information recording medium.

[0006]

The first object is to provide an information recording apparatus having an information recording medium and an optical system for irradiating the information recording medium with a light beam for information recording / reproducing,
The optical system has a movable optical system in which an objective lens for irradiating the light beam onto the information recording medium and a means for deflecting the light beam are integrated, and a means for making a parallel light beam incident on the movable optical system. The second object is a disk-shaped recording medium, which is divided into substantially concentric circular blocks composed of a plurality of tracks, and the tracks are in each block. And an information recording medium having an identification signal for identification, the third purpose is to position a light spot on the target track for recording and reproducing information on the track of the disk-shaped recording medium. When using the recording medium divided into substantially concentric blocks composed of a plurality of tracks, enter the block number indicating the target track and the track number in it, After identifying the target block number of locks is measured, the information record reproduction method comprising so as to position the light spot to identify the target track by measuring the track in the block, are achieved, respectively.

In this specification, in order to explain the outline of the present invention, the tracking system is described in Japanese Patent Application No. 48-12968, "Information recording / reproducing method, and The device "(Japanese Patent Publication No. 54-1572)
However, there is no problem in implementing the present invention with other tracking methods as will be described later. Further, the pull-in is described in Japanese Patent Application No. 50-9721, "Automatic pull-in system" (see Japanese Patent Publication No. 55-16325) filed by the present inventors. Therefore, here, the description will focus on the information retrieval method and the apparatus.

[0008]

In order to search for a desired information groove from a medium in which information is recorded at a high density by using light, in the field of view of the focusing objective lens (the range on the medium except the objective lens) Since it is not possible to look into the information groove, first, the desired information groove is first made to be within the field of view of the focusing objective lens. Secondly, the desired information groove is distinguished from other information grooves in the field of view. Moreover, it is necessary to perform the above operation in a short time. Therefore, with respect to the first method, the position setting error of the objective lens is made smaller than the field of view. This is easily accomplished by choosing the moving mechanism of the optical system, including the objective lens. For example, if a computer disk moving mechanism that moves a head of about 600 g is used, the positioning accuracy is about 20 μm. Since the field of view of the objective lens is usually about 500 μm, the first requirement can be satisfied. Regarding the second, the frequency of microvibration in a direction perpendicular to the traveling direction of the information groove used for tracking operation for accurately tracking the information groove is changed for each information groove in the information groove in the visual field, and the frequency is changed. The information groove is distinguished by detecting.

Next, the contents of the present invention will be described in more detail. (1) Explanation of recording principle: tracking during playback,
In order to accurately perform the pull-in and the search of the information groove, FM modulation, pulse width modulation, after adding the synchronization detection standard signal to the information signal to be recorded / reproduced at the time of recording,
A light beam, an electron beam, or the like for processing a recording medium by a modulated signal, which performs meaningful modulation as phase information such as pulse position modulation (hereinafter referred to as binary modulation) (hereinafter, these are irradiation beams (Collectively)
Intensity is modulated. Then, a recording medium that moves while slightly vibrating the intensity-modulated irradiation beam in a direction perpendicular to the traveling direction of the information groove to be created by using a signal having the same frequency and phase as the standard signal for synchronization detection. Irradiate on top. Preferably, in order to reduce the crosstalk of the reproduced image, the amplitude of the minute vibration is set to be half or less of the sum of the width of the recorded information groove and the width of the reproduction spot.

In such a state, in the present invention, the frequency of the synchronization detection standard signal is changed continuously or discontinuously to form the information groove. Here, discontinuous means that the frequency of the synchronization detection standard signal included in the information signal recorded in the information groove of a constant length and the frequency of minute vibration of the information groove are the same. In particular, the information groove of the fixed length is generally equal to the unit information groove. Here, the unit information groove means a case where the information signal recorded therein has a series of meanings. For example, if the information to be recorded is a television signal, information for one frame may be considered. Then, generally, the unit information grooves are formed substantially in parallel.

A case where a disk is taken as a recording medium and the sync detection standard signal is discontinuously changed will be described. First, according to the order of recording all the unit information grooves to be recorded, an appropriate number (n) of unit information grooves are grouped into one block and all the recorded information grooves are N
Divide into blocks. In one block, the position of the irradiation beam is stopped at one point in the radial direction of the disk only for one rotation of the disk, and the above-mentioned recording is performed by using the synchronous detection standard signal of a certain frequency.

Similarly, synchronously detection is performed each time the irradiation position of the light beam in the disk radial direction changes while moving the irradiation beam discontinuously in the disk radial direction with a pitch interval σμm, that is, for each unit information groove. The above recording is performed by changing the frequency of the standard signal at the frequency interval Δf.

As a result, the disc on which information is recorded becomes as shown in FIG. On the disk 1, the information grooves are concentric circles with a pitch interval of σμm. From the first information groove 3 to the last information groove 4 of a certain block, although not shown in the figure, n information grooves are arranged in one block.
Letting f _{0 be} the frequency of the synchronization detection standard signal of the first information groove 3 (the frequency of minute vibration in the direction perpendicular to the traveling direction of the information groove), the frequency of the synchronization detection standard signal of the last information groove 4 is f.
₀ + a (n-1) × Δf. With respect to each block composed of n information grooves, there is a change in the synchronization detection standard signal for each information groove as described above. The center of rotation of the disk 1 is indicated by 2. From FIG. 1, a specific information groove on the disk corresponds to a specific sync detection standard signal frequency in a specific block.

Further, as another recording method, the position of the irradiation beam in the disk radial direction is continuously changed at a constant speed, and at the same time, the frequency of the synchronous detection standard signal is continuously or discontinuously changed. There is also a method of recording. As a result, the information groove in which the information is recorded becomes spiral on the disc, and the information groove being reproduced by detecting the synchronization detection standard signal recorded in the information groove is the number of the information groove from the beginning of the block. I know if it is.

(2) Description of principle of reproduction: Next, an information groove in which desired information is recorded is searched for from a recording medium such as a disc or a disc sheet on which information is recorded by the above-mentioned method, and is reproduced accurately. Describe the principle. First, it is designated which block the information groove in which desired information is recorded belongs and which number from the beginning of the block. For this purpose, the unit information groove in which specific information is recorded and the block number and the number within the block are stored in the storage device, and the desired information is only the block number and the number within the block. It must be able to be expressed by. By specifying the block number corresponding to the desired information and the number of the information groove in the block, the position of the information groove on which the desired information is recorded on the disc is determined. Next, the light beam is moved to the above position in the direction perpendicular to the traveling direction of the information groove.

However, in order to move the light beam,
The light deflecting means and the focusing optical system must be moved at the same time.
However, generally, these are heavy, and the positioning accuracy is poor because a mechanism that moves at high speed is used to increase the speed of search. The error in this positioning accuracy is a μm. There is also a setting error between the disc and the above moving mechanism. This is set to b μm. Further, if the disk is in a rotating state, there is always eccentricity (a deviation between the center of rotation and the center of the disk). This eccentricity amount is c μm.
Then, the error between the moved light beam and the desired information groove is (a + b + c) μm. This amount must be smaller than the field of view of the focusing objective lens. Normally, a
Is about 20 μm, b is about 20 μm, and c is about 20 μm.
Sufficiently small for a field of view of 500 μm. Therefore, the desired information groove is not removed from the visual field. In order to find a desired information groove from the information grooves within the above error, the frequency of the synchronization detection standard signal of the information groove is set to Δ as described above.
Although it is changed by f, the number of information grooves to be distinguished (the number in the block) may be larger than the number of information within the above error. That is, n × σ ≧ a + b + c may be satisfied.

Further, the maximum frequency of the synchronization detection standard signal of the information groove in the block must be smaller than the frequency f which does not affect the signal obtained by binary-modulating the information during reproduction. That is, f> f ₀ + (n−1) × Δf
Must be

As described above, the frequency interval Δf, the total number of information grooves in the block and the like are determined from the reproduction condition.

When the light beam that has moved to the vicinity of the desired information groove is pulled in so as to eliminate the blurring with the information groove due to disturbance, the time for which the light beam crosses one information groove becomes longer, The photoelectric conversion output signal of the reflected light is demodulated in time, the synchronization detection standard signal is extracted, the frequency is measured, and the deviation between the crossed information groove and the desired information groove is detected. As a result, the light beam is moved to the desired information groove by the optical deflector, tracking is performed by the light beam to follow the desired information groove, and the desired information is read.
By the above reproducing method, the information groove in which desired information is recorded can be found and reproduced accurately.

In the present information recording / reproducing system in which the sync detection standard signal is recorded together with the information signal at the time of recording and is used for pull-in and tracking at the time of reproduction, changing the frequency of the sync detection standard signal for each information groove at the time of recording means reproduction. It goes without saying that there are no problems in the pulling in of time and the tracking operation.

For an information groove continuously formed like an information groove spirally recorded on a disk, the frequency of the sync detection standard signal is recorded discontinuously or continuously during recording. There are two ways. When the frequency of the synchronization detection standard signal is changed discontinuously, the principle described for the concentric recording groove formed on the disk is established. In addition, when the frequency of the sync detection standard signal is changed continuously during recording, the width of the information groove is set to be within the range of the changed frequency between the unit information grooves such as one rotation of the disc. If the measures are taken, the above-mentioned principle holds.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings. <Embodiment 1> FIG. 2 is a block diagram of an information recording apparatus according to an embodiment of the present invention. Hereinafter, taking the case of a disk as an example, an information recording apparatus using an optical beam as a disk irradiation beam will be described. A configuration, a recording method, and an example of a disc in which information is actually recorded on a recording medium will be described.

In FIG. 2, a signal from an information source 10 such as a VTR or a television receiver is modulated by a modulator 11 according to the signal source. Further, the synchronization detection standard signal generated from the frequency variable oscillator (for example, voltage controlled oscillator) 12 is modulated by the modulator 13 and added by the adding means 14.
Is added to the signal from the modulator 11 and then subjected to the binary modulation described above. Then, the modulated signal 15 is input to the drive circuit 16 of the light beam intensity modulation means (for example, EO modulator or AO modulator) 17.
A light beam 19 generated from a laser light source 18 is modulated by a light beam intensity modulator 17, and an optical deflector 20 such as an AO deflector or an EO deflector and a condensing optical system 21 form a photosensitive material on a rotating disk 22. It is focused and the information groove is recorded.

At this time, the output of the oscillator 12 is changed to the optical deflector 2
0 to the drive circuit 23 to drive the optical deflector 20 to slightly oscillate the light beam in the radial direction of the disk. Further, the input relationship of the control circuit 26 for searching will be described. A television signal is taken as an example of the signal source 10. In this case, one frame corresponds to one information groove. In the case of retrieval, there is also a method of associating the content of the frame to be stored with the information groove, but since the configuration becomes complicated, here, the frame to be stored by another configuration (not described in the embodiment of the present invention) Take, for example, the case where the contents and the order of memorization are already known.

The signal processing circuit 24 extracts the vertical synchronizing signal from the television signal. The vertical synchronizing signal is contained in the television signal as a 2-pulse signal in one frame. Through a circuit such as a flip-flop, one pulse is displayed as an output for one frame. The measuring device 27 measures the pulse signal 25 which is the output of 24 with a counter, and carries out a carry when the number of information grooves allowed in one block becomes a value of n or more which is the upper limit. The carried number (block number) is sent to the memory circuit 28 in the form of a signal 29. Similarly, the carry-only number is sent to 28 in the form of signal 30. In this configuration, it is 29 signals that represent the number of blocks,
It is the 30 signals that represent the numbers within a block. In the frequency control circuit 26, the measured value from the measuring instrument 27 is D / A
It is converted into an analog voltage by the converter and input to the oscillator 12. As a result, the oscillation frequency from the oscillator 12 changes for each information groove in the block. This interval is determined by the minimum set value of the D / A converter.

In the memory circuit 28, the signal processing circuit 2
The output 25 from 4 is used as a clock to store the contents of the signals 29 and 30 corresponding to the order of recording. At the same time, the output from the frequency control circuit 26 is input to the storage circuit 28. As a result, the number of blocks in which the recording information groove is recorded and the number of the blocks in the recording information groove can be associated with each other, and the frequency of the sync detection standard signal can be associated with it.
With the signal of 25, the drive circuit 31
Sends the mechanism 32 for moving the focusing optical system by .sigma..mu.m in the radial direction of the disk. This can be achieved with a normal motor.

Next, the frequency at the time of recording (of the sync detection standard signal) will be described in comparison with the frequency of the signal of the information source. As an information source signal, an example of recording an NTSC television signal will be taken. An NTSC signal is FM-modulated by the modulator 11. The carrier frequency at that time is 8M
Select near Hz and record the lower sideband on the disc.
Audio is FM-modulated near 2 MHz and recorded. At this time, the spectrum (of the frequency) of the output of the modulator 11 is shown in FIG.

The frequency band 41 shown in FIG. 3 is obtained by FM-modulating a video signal and then extracting a part of the lower sideband and the upper sideband. Reference numeral 42 denotes both sidebands obtained by FM-modulating voice. Sync detection standard signal to video signal band 41
There is one way to insert it inside. According to this method, the frequency interval Δf for each information groove of the sync detection standard signal can be made large, but it must still be inserted at a low level so as not to affect the video signal. Specifically, the band 43 shown by diagonal lines in FIG. 3 is used. At this time, the modulator 13 performs FM modulation with a carrier frequency of 4 MHz.

Another method is to bring the band 43 'of the sync detection standard signal outside the band of the video signal, as shown in FIG. With this method, the level during recording is high, and the sync detection standard signal can be detected reliably during playback,
Δf cannot be set high. In this method, the modulator 1 is used for recording.
3 is unnecessary. If you try to put information for 30 minutes of video playback time on a disc rotating at 1800 rpm,
4000 information grooves are required. When all of this information is recorded on a 300φ disc, the pitch interval σ becomes about 2 μm. If the mathematical formula described in the explanation of the principle is used, the block can be roughly divided into 540, and the number of information grooves in the block can be 100. If the frequency interval Δf is set to 16 kHz so as not to affect the video signal, the upper limit of the sync detection standard signal is 2 MHz in the method of FIG.
There is no problem below.

As described above, the information recording apparatus of the present invention has a total number of tracks of 54000 (pitch interval σ is about 2 μm) as an information recording medium, a block number of 540, 100 tracks accommodated in one block, and Each track in one block has a frequency interval Δ as an identification signal.
It was possible to obtain discs identified at f = 16 kHz.

<Second Embodiment> Next, an example of an information reproducing apparatus according to the present invention will be described with reference to the block diagram shown in FIG. However, since the device relating to the pulling-in and tracking mechanism is described in detail in the above-mentioned patent application specification, only the operation of the present embodiment will be described briefly, and only the part relating to the device for retrieving information will be described in detail.

In FIG. 5, a laser beam 51 is generated from a laser light source 50, passes through a semitransparent mirror 52, passes through a light deflecting means 53 (preferably a galvanometer mirror), and a focusing optical system 54, and rotates. Alternatively, microspots are formed on the disc sheet 55. As an optical system of this apparatus, a light deflecting means 53 and a condensing optical system (objective lens) 54 are integrated to form a movable optical system as shown in FIG. A laser beam 51 is emitted from a laser light source 50 as means for injecting.

Reflected light 56 from the disk 55 enters a photoelectric conversion means 57 through a condensing optical system 54, a light deflecting means 53 such as a galvanometer mirror, and a semitransparent mirror 52. Next, the photoelectric conversion output signal is input to the demodulator 58, the synchronization detection standard signal when the micro spot crosses the information groove is extracted, and is input to the frequency measuring means 60.

At this time, the demodulator 58 has a filtering function of passing only the shaded band in FIGS. 3 and 4 in order to remove the synchronization detection standard signal. Signals other than the synchronization detection standard signal pass through the video demodulator 61 and are input to the television receiver 62 to reproduce the image. When the sync detection standard signal is FM-modulated as shown in FIG. 3, the demodulator 59 for the sync detection standard signal is required, but it is not necessary in the signal processing as shown in FIG. The photoelectric conversion output signal passes through the AM detector 63, undergoes envelope detection, and is input to the synchronous rectifier 64. In 64, the synchronization detection standard signal which is the output signal of 58 is used to detect the deviation between the microspot and the center of the information groove and the direction thereof. This becomes a signal for tracking control.

Next, a search method and its device will be described. The recording number of the desired information groove is designated by the order designating circuit 65 which designates the information groove in the recording order in which the desired information content is recorded. In the description of the present invention, the contents of the order designation circuit 65 are not described in detail, but only the role is described. The output of 65 is inputted to the memory circuit 28 used for the description of the recording apparatus, and the memory circuit 28 designates which block the desired information belongs to and which information groove from the beginning of the block exists. Input to the circuit 66.

In the block designating circuit 66, the light deflection means 53
A mechanism for moving the focusing optical system 54 and the focusing optical system 54 integrally (movable optical system)
Designation is given to the drive circuit 68 which drives 67, and 67 is moved to near the desired information. The position detector 69 detects the position of the movable optical system 67 and feeds it back to 66 to accurately perform positioning. Reference numeral 70 converts the frequency of the desired information groove into a voltage, measures the frequency of the synchronous detection standard signal of the information groove through which the microspot is currently passing by the frequency measuring means 60, and passes it by the comparator 71. The shift between the information groove and the desired information groove is detected, the jump circuit 72 for jumping the light beam for each information groove is moved, and the light deflecting means 53 moves the light spot to the desired information groove to obtain the desired information groove. When the light spot reaches the information groove, the comparator 71
Output becomes zero, the output of the synchronous rectifier 64 is input to the drive circuit 73 of the optical deflector at this time to perform tracking, reproduce desired information, and output video to the television receiver 62.

[0037]

As described above in detail, according to the present invention, each of the above objects can be achieved by the above solving means. That is, according to the present invention, the recorded information grooves are divided into blocks, and the information grooves are arranged in order in each block. Therefore, the desired information groove order can be read, and the desired information is searched for. The time can be remarkably shortened, and a great effect can be brought about in speeding up information retrieval. As a result, the improved information recording apparatus, the recording medium recorded by the improved information recording apparatus, and the information recording / reproducing method using the recording medium can be realized.

[Brief description of drawings]

FIG. 1 is a perspective sectional view of an essential part of an information recording medium according to an embodiment of the present invention.

FIG. 2 is a block diagram of an information recording apparatus according to an embodiment of the present invention.

FIG. 3 is an output spectrum of a modulator.

FIG. 4 is an output spectrum of a modulator.

FIG. 5 is a block diagram of an information reproducing apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 50 ... Laser light source 51 ... Laser beam 52 ... Semi-transparent mirror 53 ... Optical polarization means 54 ... Condensing optical system (objective lens) 67 ... Movable optical system

Claims (3)

[Claims] 1. An information recording apparatus having an information recording medium and an optical system for irradiating the information recording medium with a light beam for information recording and reproduction, wherein the optical system irradiates the information recording medium with the light beam. An information recording apparatus comprising a movable optical system in which an objective lens and a means for deflecting the light beam are integrated, and a means for making a parallel light beam incident on the movable optical system. 2. A disk-shaped recording medium, wherein the recording medium is divided into substantially concentric circular blocks composed of a plurality of tracks, and the tracks have an identification signal for identifying in each block. An information recording medium formed by. 3. A recording medium divided into substantially concentric blocks composed of a plurality of tracks when positioning a light spot on a target track for recording / reproducing information on / from a track of the disk-shaped recording medium. Enter the block number indicating the target track and the track number in it, measure the number of blocks to identify the target block, then measure the tracks in the block to identify the target track and position the light spot. A method of recording and reproducing information.