JPH043028B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a recording/reproducing apparatus for recording or reproducing information using a signal conversion means on a disc-shaped record carrier having a track on which information is recorded or a track for recording information. This invention relates to an information track retrieval device.

2. Description of the Related Art A conventional information track retrieval device is disclosed in, for example, Japanese Patent Application No. 1983-39883.

FIG. 6 is a block diagram showing an example of this conventional information track retrieval device, in which a light beam 2 generated from a light source 1 such as a semiconductor laser passes through a coupling lens 3, a beam splitter 4, and a reflecting mirror 5. The light is reflected by a converging lens 6 and focused onto a disc-shaped record carrier 7. The record carrier 7 is attached to the rotating shaft of a motor 8 and rotates at a predetermined number of rotations. The recording carrier 7 has concentric or spiral grooves (hereinafter referred to as tracks) on a base material, and is composed of a recording material layer and a protective layer provided on the grooves. Address signals are provided sequentially from the inner circumference to the outer circumference. The reflected light of the light beam 2 reflected from the record carrier 7 passes through the converging lens 6 again, is reflected by the reflecting mirror 5 and the beam splitter 4, and is irradiated onto the photodetector 9 having a two-split structure. . The converging lens 6 is attached to a tracking element 10, and the tracking element 10 is configured to be able to move the converging lens 6 in the radial direction of the record carrier 7, that is, in a direction substantially perpendicular to the direction of the tracks on the record carrier 7. ing. The moving parts of the light source 1 , coupling lens 3 , beam splitter 4 , reflector 5 , photodetector 9 , tracking element 10 and speed detector 11 are attached to a transfer table 12 , and the recording is performed by a linear motor 13 . It is configured to move integrally in the radial direction of the carrier 7. The speed detector 11 is composed of a moving part made of a rod-shaped magnet fixed to the transfer table 12 and a fixed part made of a coil, and outputs a signal corresponding to the moving speed of the transfer table 12.

Tracking control for controlling the light beam 2 focused on the carrier 7 so that it is always positioned on a track will be described. Each signal of the photodetector 9 is input to a differential amplifier 14, and the differential amplifier 14 outputs a difference signal between the respective signals of the photodetector 9. The direction of the dividing line of the photodetector 9 is the track direction of the track pattern included in the reflected light on the photodetector 9, and the signal from the differential amplifier 14 determines the positional relationship between the light beam 2 and the track on the record carrier 7. The signal representing the tracking control signal, that is, the tracking control signal, is well known and will not be described in detail. The signal from the differential amplifier 14 is sent to a switch 15, a phase compensation circuit 16 for compensating the phase of the tracking control system, and a drive circuit 17 for driving the tracking element 10.
is transmitted to the tracking element 10 via. Therefore, the tracking element 10 is the differential amplifier 1
The converging lens 6 is moved in accordance with the signal 4, and the light beam 2 on the record carrier 7 is controlled so as to be positioned on the track.

The range of movement of the tracking element 10 is
The distance is approximately 500 μm, and if the transfer table 12 moves significantly, tracking control will be lost. In order to prevent this, the linear motor 1 is operated so that the tracking element 10 moves around its natural state, that is, so that the signal of the drive circuit 17 becomes zero level on average.
3 to control the movement of the transfer table 12.
To explain this transfer control, the differential amplifier 1
The signal No. 4 is sent to a switch 15, a phase compensation circuit 18 for compensating the phase of the transfer control system, and a linear motor 13.
is transmitted to a linear motor 13 via a drive control circuit 19 for driving and controlling the movement, and the linear motor 13 moves the transfer table 12 so that the tracking element 10 moves around its natural state. The switch 15 is for disabling tracking control and transfer control.

The signal from the speed detector 11 is input to a drive control circuit 19, and by feeding back the speed signal, the drive control of the linear motor is made more stable.

Recording and reproduction of signals will be explained. Record carrier 7
When recording a signal on the upper track, light source 1 is
The intensity of the light beam 2 generated from the recording device is modulated depending on the signal to be recorded. The recording material at the location irradiated with the intense light beam 2 changes state or shape, and a signal is recorded on a track on the record carrier 7. When reproducing a signal recorded on a track on the record carrier 7, the light beam 2 generated from the light source 1 is
The light reflected from the track is received by a photodetector 9, and a composite signal of the respective signals from the photodetector 9 is obtained.

Note that in the optical recording/reproducing device, focusing is controlled so that the beam diameter of the light beam 2 irradiated onto the record carrier 7 is always constant, but since this is not directly related to the present invention, it will be described in detail. Avoid.

The basic structure of the optical recording and reproducing apparatus has been described above, and one important function of this apparatus is to search for a desired track at high speed and stably, and this search will be explained below.

The search system is composed of an information processing control device 20 including a microcomputer. When the desired track address A _O is input to the address input device 21, the information processing control device 20 reads the address A ₁ of the track where the light beam 2 is currently located, and calculates (A ₁ −A _O ). do. ｜A ₁ −A _O ｜≧N(｜
A ₁ −A _O | represents the absolute value of (A ₁ −A _O ), and N is a positive integer. ), the information processing control device 20 sends the value of |A ₁ −A _O | and a direction signal to the drive control circuit 19, and inputs the value of |A ₁ −A _O | to the counting circuit included in the drive control circuit 19. At the same time, the switch 15 is released to disable the tracking control and the transfer control. The drive control circuit 19 drives the linear motor 13 to move the transfer table 12 in the direction where a desired track exists.
The signal from the differential amplifier 14 is input to a track crossing detection circuit 22, and the signal from the track crossing detection circuit 22 is input to a drive control circuit 19. When the transport stage 12 moves in the radial direction of the record carrier 7, a signal indicating that the light beam 2 on the record carrier 7 has traversed the track is outputted from the differential amplifier 14, and the track crossing detection circuit 22 outputs a signal indicating that the light beam 2 on the record carrier 7 has traversed the track. 1
4 is waveform-shaped and transmitted to the drive control circuit 19. A counting circuit included in the drive control circuit 19 counts the signal from the track crossing detection circuit 22, so that the light beam 2 on the record carrier 7 is |A ₁ −A _O |
The drive control circuit 19 detects that it is on the main track and sends a coincidence signal to the information processing control device 20. The information processing control device 20 transmits a signal to stop the linear motor 13 to the drive control circuit 19 and short-circuits the switch 15 to operate tracking control and transport control, so that the light beam 2 is positioned on the record carrier 7. ( _hereinafter this search will be referred to as a coarse search). A _O =
If A ₂ , the search ends, but if |A ₂ −A _O |≧N, the above-mentioned rough search is performed again. Also |
If A ₂ −A _O |<N, the information processing control device 20
When the switch 15 is opened, the drive circuit 17 is opened.
By sending a signal to drive the tracking element 10 and short-circuiting the switch 15 again, one track interlacing scan (hereinafter this scan is referred to as jumping) is performed, and this jumping is |
After repeating A ₂ −A _O | times, the address A ₃ of the track where the light beam 2 is located is read (hereinafter this search will be referred to as a fine search). If A _O = A ₃ , the search ends, but if A _O ≠ A ₃ (A _O ≠ A ₃ means that A _O and A ₃ are not equal), the above-mentioned coarse search and fine search are performed. Repeat to search for the desired track.

By the way, in order to record digital information on a track on the record carrier 7, since the length of the information is undefined, it is advantageous to record one track by dividing it into a plurality of information areas (hereinafter referred to as sectors). In order to distinguish these multiple sectors from each other and to clarify the number of the current sector (sector number) during recording and playback, a sector separator area is provided at the beginning of each sector, and a At least three address signal recording areas (hereinafter referred to as address areas) are provided in advance. An example of the record carrier is shown in FIG.

The record carrier 7 in FIG. 7 is composed of sector areas S ₁ to _{S 32} for recording information, sector separator areas SP ₁ to SP ₃₂ for separating each sector area, and address areas TA ₁ and TA ₂ for indicating track addresses. ing.

8a is a plan view of the disk along the track of sector area S ₁ , sector separator area SP ₁ , and address area TA ₁ of track 22 in FIG. 7, and FIG. 8b is a sectional view of the same. be. The depth of the track is 8, and the width of the groove is W. 8 is about 1/8 of the wavelength λ of the laser beam, and W
is approximately 0.6 μm due to high density. address area
TA ₁ (also TA ₂ ), sector separator area SP ₁
(Similarly for SP ₂ to _{SP 32} ), each piece of information is provided in advance on the disk depending on the presence or absence of a groove, and is created simultaneously at the time of groove cutting.

Therefore, it is necessary to perform the above-mentioned search in a short time, and in order to perform a high-speed search, the linear motor 13
It is necessary to drive the transfer platform 12 in a desired track direction at high speed. However, when using the record carrier 7 having the above-described structure, when the light beam 2 on the record carrier 7 traverses the track at high speed, the converged light beam 2 moves from A to A, as shown in FIG. 9a. Difference amplifier 1 in Fig. 6
The output signal of No. 4, that is, the tracking signal, has an S-shaped signal waveform of one cycle (FIG. 9b). However, in the address area or sector separator area, the tracking signal is disturbed because the reflected light is affected by diffraction due to the address information or sector separator information (uneven pits) created on the tracking, as shown in Figure 10a. Figure 10b).

The tracking cross-cutting detection circuit 22 in FIG.
The tracking signal of the differential amplifier 14 is waveform-shaped and transmitted to the drive control circuit 19. A counting circuit included in the drive control circuit 19 counts signals from the track crossing detection circuit 22.

Problems to be Solved by the Invention However, with the above configuration, it is not possible to accurately count the tracks traversed by the beam in the sector separator area or the address area due to the effects of uneven pits. Therefore, coarse searches had to be performed many times, making it difficult to perform high-speed searches.

In view of the above, it is an object of the present invention to provide an apparatus which eliminates the drawbacks of the conventional apparatus and is capable of searching for a desired track at high speed and stably.

Means for Solving the Problems The present invention comprises a converting means for reproducing or recording a signal from a track on a record carrier, a storage means for storing an output signal reproduced from the converting means for one rotation of the record carrier, a first moving means for moving the scanning position of the converting means in a direction substantially perpendicular to the track direction on the record carrier; and a first moving means for moving the scanning position of the converting means in a direction substantially perpendicular to the track direction on the record carrier. a second moving means that moves including the first moving means; and driving and controlling the first moving means so that the scanning position of the converting means is always on a track on the record carrier. a control means, a counting means for counting the output signals of the converting means traversing a track on the record carrier, a switching means controlled by the stored signal of the storage means, a phase comparison means, and an output of the phase comparison means. and a frequency generating means for generating a frequency based on the signal,
The phase comparison means is an information track retrieval device that compares the phase of the output signal of the conversion means with the output signal of the frequency generation means.

Effects According to the present invention, with the above-described configuration, the scanning position of the converting means can be changed at high speed to a second position including the first moving means in a direction substantially perpendicular to the track direction on the record carrier.
When moved by the moving means, the address area or sector separator area is stored in advance in the storage means, and when the switch means is controlled by this signal,
The switch means cuts off the output signal of the conversion means which has crossed the track input to the phase comparator means in the address area or sector separator area.

When the input signal disappears, the phase comparison means compares the phase with the output signal of the conversion means inputted through the immediately preceding switch means, and the frequency is controlled by the frequency generation means in response to the phase error signal. The output signal of the frequency generating means is counted as a track crossing signal by the counting means.

Example The present invention will be described in detail below with reference to the drawings.

FIG. 2 shows one embodiment of the present invention, and in explaining FIG. 2, the explanation of parts that overlap with FIG. 6 will be simplified.

51 is a light source, 52 is a light beam, 53 is a coupling lens, 54 is a beam splitter, 55 is a reflecting mirror, 56 is a converging lens, 57 is a record carrier, 59
is a photodetector with a two-part structure. Each signal of the photodetector 59 is sent to a differential amplifier 64 and a combining circuit 72.
has been entered. The signal from the differential amplifier 64 is input to a track crossing detection circuit 73 and a switch 65, and the output of the switch 65 is input to phase compensation circuits 66 and 68. Phase compensation circuit 6
The signal No. 6 is input to the drive circuit 67, and the signal from the drive circuit 67 is input to the tracking element 60, respectively. The signal of the phase compensation circuit 68 is transmitted to the linear motor 63.
A signal from the drive control circuit 69 is input to the linear motor 63 to drive and control the linear motor 63 . The speed detector 61 is the transfer table 6
2, and the signals are input to the drive control circuit 69 and the track crossing detection circuit 73, respectively. Further, the signal from the track crossing detection circuit 73 is input to the drive circuit 69.

The motor 58 is for rotating the record carrier 57, and a frequency generator (not shown) inside the motor 58 generates a frequency according to the rotation, and this signal is input to the waveform shaping circuit 74. The waveform shaping circuit 74 amplifies and shapes the input signal,
The signal is input to a speed control circuit 75, a phase control circuit 77, and a track crossing detection circuit 73, respectively. Speed control circuit 75 transmits a signal to drive circuit 78 so that motor 58 rotates at a predetermined speed. The signal generated by the frequency generation circuit 76 is input to the phase control circuit 77. The phase control circuit 77 transmits the phase difference between the signal from the waveform shaping circuit 74 and the signal from the frequency generation circuit 76 to the drive circuit 78 . Drive circuit 78
drives the motor 58 based on the signals from the speed control circuit 75 and the phase control circuit 77. Therefore, the motor 58 rotates while being controlled in speed and phase.

The address input device 71 is for inputting information necessary for a search, and the signal from the address input device 71 is input to the information processing control device 70. The information processing control device 70 includes a switch 65, a drive circuit 67, and a drive control circuit 69 for controlling as necessary.

Figure 1 shows the track crossing detection circuit 73 of Figure 2.
In this example, a is the signal output from the differential amplifier circuit 64 in FIG.
has been entered. Cutoff frequency _C1 of low pass filter 79 and low pass filter 81
The relationship between the cutoff frequency _Cd2 is _C1 < _C2 .
The signal from the low pass filter 79 is transmitted to the switch 87 via a comparator 80 which converts it into a binary signal. Further, the signal from the low-pass filter 81 is passed through a comparator 82 that converts it into a binary signal to a switch 83, a phase comparison circuit 84, a low-pass filter 85, a variable frequency generation circuit 86, and a switch 87.
has been communicated to. The phase comparison circuit 84 compares the phase of the signal input via the switch 83 and the signal generated by the variable frequency generation circuit 86, and the phase error signal is sent to the low-pass filter 85.
The high frequency component noise is removed. The variable frequency generation circuit 86 is a circuit that generates a frequency according to an input signal. Therefore, the frequency of the signal input to the phase comparison circuit 84 via the switch 83 and the signal generated by the variable frequency generation circuit 86 are the same.

b is a signal output from the waveform shaping circuit 74 in FIG. 2 and is input to the frequency divider 88. Frequency divider 88
The frequency division ratio is set so that one pulse is output every time the motor 58 rotates once. One edge of the waveform of the signal output from the frequency divider 88 is extracted by a differentiating circuit 89 and inputted to a counter 90 . The counter 90 sequentially counts the internal clock, and is configured so that when a signal is input from the differentiating circuit 89, the counter value is cleared. The output (counter value) of counter 90 is RMA (Random Access Memory)
91 address.

c is the record carrier 5 on which the respective signals obtained by the photodetector 59 are synthesized by the synthesis circuit 72 in FIG.
The reproduced signal of No. 7 is input to the detection circuit 92.
The detection circuit 92 detects the input signal and transmits it to the waveform shaping circuit 93. The waveform shaping circuit 93 binarizes the input signal and transmits it to the RAM 91.
The RAM 91 stores signals input from the waveform shaping circuit 93 and outputs the stored signals to the switch 83 according to instructions from the information processing control device. The switch 83 opens and closes the switch according to a signal input from the RAM 91.

d is a signal output from the speed detector 61 in FIG. 2 and is input to the comparator 94. The output signal of the comparator 94 becomes High as the speed of the transfer table 62 increases.
state, and the switch 87 transmits the signal. If the output signal of the comparator 94 is in a low state, the switch 87 selects the output signal of the comparator 80 and outputs it to e. Further, when the output signal of the comparator 94 becomes High, the output signal of the variable frequency generation circuit 86 is selected and outputted to e. The output of switch 87 is transmitted to drive circuit 69 in FIG.

Therefore, as an initial operation, the information processing control device 7
0 inputs the data write command signal and the data write command signal to the RAM 91 of the track crossing detection 73 for a time corresponding to one rotation of the record carrier 57. Then, the RAM 91 stores the signal which is detected by the detection circuit 92 on the reproduced signal c synthesized by the synthesis circuit 72 and binarized by the waveform shaping circuit 93. FIG. 3 shows each waveform at this time. A is the reproduced signal c, B is the output signal of the detection circuit 92, and C is the output signal of the waveform shaping circuit. Therefore, the address area and sector separator area on the track are stored in the RAM 91 for one rotation of the record carrier.
(The track at this time is an unrecorded track.) Next, the search will be explained. Address input device 71
When the desired track address A _O is input,
The information processing control device 70 reads the address A ₁ of the track where the light beam 52 is currently located, and reads (A ₁ −
Calculate A _O ). If |A ₁ −A _O |≧N (|A ₁ −A _O | represents the absolute value of (A ₁ −A _O ), and N is a positive integer), then the information processing control device 70 | A ₁ −
The value of A _O | and the direction signal are sent to the drive control circuit 69 to the counting circuit included in the drive control circuit 69.
The value of A ₁ -A _O | is preset, and at the same time the switch 65 is opened to disable tracking control and transfer control. The drive control circuit 69 drives the linear motor 63 to move the transfer table 62 in the direction where a desired track exists. differential amplification 64
The signal from the track crossing detection circuit 73 is inputted to the track crossing detection circuit 73, and the signal from the track crossing detection circuit 73 is inputted to the drive control circuit 69. When the transport stage 62 moves in the radial direction of the record carrier 57, the output of the differential amplifier 64 includes the light beam 52 on the record carrier 57.
A signal that crosses the track is output, high-frequency component noise is removed by a low-pass filter 79, binarized by a comparator 80, and transmitted to a switch 87. When the moving speed of the transfer table 62 is slow (i.e., just before starting acceleration or stopping), the speed detector 61
Since the signal of the comparator 94 is low, the output of the comparator 94 is in a low state, and the switch 87
Since it is in the Low state, the signal from the comparator 80 is transmitted to the drive control circuit 69, and the counting circuit included in the drive control circuit 69 counts the signal input via the switch 87. Here, the light beam 52 is transmitted to the record carrier 5.
When the sector separator area or address area on 7 is traversed as shown in FIG.
The output signal waveform of is shown in FIG. 4b. FIG. 4c shows the waveform of the output signal of the low-pass filter 79.

Next, when the moving speed of the transfer table 62 increases, the signal of the speed detector 61 becomes high and the output of the comparator 94 becomes
Since the signal from the comparator 94 is in the High state, the switch 87 transmits the signal from the variable frequency generation circuit 86 to the drive control circuit 69, and the counting circuit included in the drive control circuit 69 inputs the signal through the switch 87. Count the signals that are received. Here, when the light beam 52 traverses the sector separator area or address area on the record carrier 57 as shown in FIG. 5a, the output signal waveform of the differential amplifier 64 is as shown in FIG.
becomes. The signal from the differential amplifier 64 has high-frequency component noise removed by a low-pass filter 81, is binarized by a comparator 82, and is transmitted to a switch 83. FIG. 5a shows the signal waveform of the low-pass filter 81, and FIG. 5b shows the signal waveform of the comparator 82.

Here, as described above, data indicating the address area and the sector separator area is initially stored in the RAM 91, and is read out by the counter 90 in synchronization with the storage carrier 57. Thus, when the light beam 52 traverses the sector separator area or address area on the record carrier 57, the RAM 9
1 outputs “High” data. This signal waveform is shown in FIG. 5c.

Switch 83 indicates that the output signal of RAM 91 is low.
When in the high state, the switch is turned on and the output signal of the comparator 82 is transmitted to the phase comparison circuit 84, but when it is in the high state, the switch is turned off and the output signal of the comparator 82 is not transmitted to the phase comparison circuit 84. This situation is shown in FIG. 5d. The phase comparison circuit 84 compares the phases of the signal input from the switch 83 and the signal input from the variable frequency generation circuit 86 and transmits the phase error to the variable frequency generation circuit 86 via the low-pass filter 85. However, Switch 83
When the input signal is missing, the previous phase error is retained. The variable frequency generating circuit 86 generates a frequency according to the phase error inputted through the low-pass filter 85 and transmits it to the switch 87 .
Therefore, even if the signal input via switch 83 is absent, the output signal of variable frequency generating circuit 86 is interpolated. FIG. 5e shows a signal waveform of the variable frequency generating circuit 86.

Therefore, the moving speed of the transfer table 62 becomes faster, so that even if the light beam 52 crosses the sector separator area or the address area on the record carrier, the light beam 52 is accurately moved.
It is possible to detect that a person has crossed a track.

A counting circuit included in the drive control circuit 69 counts the interpolated signal of the track crossing detection circuit 73 so that the light beam 52 on the record carrier 57 is |A ₁ −A _O
|Detecting that the track is on the main track, the drive control circuit 69 sends a coincidence signal to the information processing control device 70. The information processing control device 70 is a linear motor 63
A signal for stopping the light beam 52 on the record carrier 57 is transmitted to the drive control circuit 69, and the switch 65 is short-circuited to operate the tracking control and transport control _.
Read. If A _O =A ₂ , the search ends, but if |A ₂ −A _O |≧N, the above-mentioned rough search is performed again. If |A ₂ -A _O | One jump is performed, and after this jumping is repeated |A ₂ −A _O | times, the address A ₃ of the track where the light beam 2 is located is read. If A _O = A ₃ , the search ends, but
If A _O 〓A ₃ , the above-mentioned coarse search and fine search are repeated to search for the desired track.

Effects of the Invention By applying the present invention, even when a light beam traverses a record carrier at high speed during a rough search, the traversed tracks can be accurately counted by interpolating the track traversal signal. Therefore, the search can be performed in a short time, and the performance and reliability of the device can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the main parts of an embodiment of the present invention, FIG. 2 is a block diagram of an information track search device according to an embodiment of the present invention, and FIG. 3 is a waveform diagram of each part of FIG. 1. , FIG. 4, FIG. 9, and FIG. 10 are diagrams showing the relationship between spots and tracks during jumping and tracking waveforms, respectively. FIG. 5 is a waveform diagram showing output waveforms at each point in FIG. 1, and FIG. The figure is a block diagram showing a conventional example, FIG. 7 is a plan view schematically showing each area on the disk, FIG. 8a is a plan view showing the address area and separator area, and FIG. 8b is a sectional view of the same. It is. 51... Light source, 56... Tracking element, 5
7... Record carrier, 64... Differential amplifier, 73...
Track crossing detection circuit, 69... Drive control circuit, 63... Linear motor, 83, 87... Switch, 81... Low pass filter, 82, 94
... Comparator, 84 ... Phase comparison circuit, 85 ... Low pass filter, 86 ... Variable frequency generation circuit, 88 ... Frequency divider, 89 ... Differentiation circuit, 90 ...
...Counter, 91...RAM, 92...Detection circuit, 93...Waveform shaping circuit.

Claims (1)

[Claims] 1. A record carrier having a track for a recorded signal or a track for recording a signal and having an address area in which address information is recorded in the track or a sector separator area for partitioning the track, and this recording medium. converting means for reproducing or recording a signal from a track on a carrier; storage means for storing an output signal reproduced from the converting means for one revolution of the record carrier; and storing the scanning position of the converting means on the record carrier. a first moving means that moves in a direction substantially perpendicular to the track direction; and a scanning position of the converting means, including the first moving means, is moved in a direction substantially perpendicular to the track direction on the record carrier. a second moving means; a control means for driving and controlling the first moving means so that the scanning position of the converting means is always on a track on the record carrier; a counting means for counting the output signal of the converting means, a switching means controlled by the storage signal of the storage means, a phase comparison means, and a frequency generation means for generating a frequency based on the output signal of the phase comparison means. An information track retrieval device, characterized in that the phase comparison means compares the phases of the output signal of the conversion means and the output signal of the frequency generation means.