JPS60256992A - Retrieval device of information track - Google Patents

Abstract

PURPOSE:To attain retrieval in a short time by interpolating a track crossing signal to attain accurate count of a crossing track when an optical beam crosses a recording medium at a high speed and a track crossing detection output is missing. CONSTITUTION:When the moving speed of a moving stand is fast, a switch 82 transmits an output of a variable frequency generating circuit 81 to a drive control circuit. When the optical beam crosses the sector separator area or the address area on the recording medium, a photodetector detects the said areas. A waveform shaping circuit 83 transmits a signal at H level in the said area and L in other area to a switch 78. When the output signal of the circuit 83 is H, the switch 78 turns off the switch and an output of the comparator 77 is not transmitted to a phase comparator circuit 79. When the signal inputted from the switch 78 is missing, the circuit 79 holds the phase error just before. Then even if the signal inputted via the switch 78 is missing, the output signal of the variable frequency generating circuit 81 is interpolated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to: Recording and reproducing in which information is recorded or reproduced by a signal converting means on a disc-shaped record carrier having a trunk on which information is recorded or a track for recording. The present invention relates to an information trunk search device for a device.

Conventional Structure and Problems There is an optical recording/reproducing apparatus as one of the suitable recording/reproducing apparatuses to which the present invention is applied.

A conventional optical recording/reproducing device will be explained with reference to FIG.

FIG. 1 is an explanatory diagram of an optical recording/reproducing device. A light beam 2 is generated from a light source 1 such as a semiconductor laser, 2 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 record 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 thereon. 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 is
The light 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 the tracking element 10
The tracking element 10 is arranged such that the converging lens 6 can be moved in the radial direction of the record carrier element, ie in a direction substantially perpendicular to the direction of the tracks on the record carrier 7. Light source 1. Coupling lens 3. Beam splitter-42 reflector 6. Photodetector9. The moving part of the tracking element 10 and the speed detector 11 is a transfer table 12.
The record carrier 7 is attached to the record carrier 7 and is configured to move together in the radial direction of the record carrier 7 by a linear motor 13. 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 according to the moving speed of the transfer table 12.

Tracking control for controlling the light beam 2 focused on the record carrier 7 so that it is always positioned on the track will be described. Each signal of the photodetector 9 is transmitted to a differential amplifier 14.
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 trunk 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 of the differential amplifier 14 is transferred to the switch 15. 0 is transmitted to the tracking element 10 via a phase compensation circuit 16 for compensating the phase of the tracking control system and a drive circuit 17 for driving the tracking element 1o. Therefore, the tracking element 1o is connected to the differential amplifier 1.
The converging lens 6 is moved according to the signal of 4, and the recording carrier 7 is
The upper light beam 2 is controlled to be positioned on the track.

The range in which the tracking element 10 can move is about 500 μm, and if the transfer stage 12 moves too far, the tracking control will be lost. In order to prevent this, the linear motor 13 is driven so that the tracking element 10 moves around its natural state, that is, the signal of the drive circuit 17 becomes zero level on average, and the movement of the transfer table 12 is controlled. It's in control. To explain this transfer control, the differential amplifier 14
The signal of switch 15. Phase compensation circuit 18 for compensating the phase of the transfer control system. The signal is transmitted to the linear motor 13 via a drive control circuit 19 for driving and controlling the linear motor 13, and the linear motor 13 is connected to the tracking element 1.
The transfer table 12 is moved so that 0 moves around the natural state. The switch 15 is for disabling tracking control and transport control.

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

Recording and reproduction of signals will be explained. When recording a signal on a track on the record carrier 7, the intensity of the light beam 2 generated from the light source 1 is modulated in accordance with the recording signal while the tracking control and the transport control are operated. The recording material at the location irradiated with the intense light beam 2 changes state or shape, and a signal is recorded on the 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 made to have a weak constant intensity while the tracking control and transport control are in operation, and the light beam 2 generated from the light source 1 is made to have a weak and constant intensity, and the light beam 2 that is reflected from the track is The light is received by the photodetector 9, and a composite signal of the respective signals of 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 configuration of the optical recording/reproducing device has been described above, and one important function of this device 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. Address A of the desired trunk in the address input device 21. When input, the information processing control device 2o reads the address A1 of the track where the light beam 2 is currently located, and calculates (A, -A.). IAl-A01≧N(IAl-Aolba(A1-Ao
), and the dimension N is a positive integer. ), the information processing control device 20 sends the value of IAl-Aol and the direction signal to the drive control circuit 19, presets the value of IAl-Aol in the counting circuit included in the drive control circuit 19, and simultaneously turns on the switch 15. It is opened and the tracking control and transfer control are disabled. The drive control circuit 19 drives the linear motor 13 to move the transfer platform 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 transfer 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 crosses the track is outputted from the differential amplifier 14, and the track crossing detection circuit 22 This signal is waveform-shaped and transmitted to the drive control circuit 19. The counting circuit included in the drive control circuit 19 counts the signal from the trunk crossing detection circuit 22, detects that the light beam 2 on the record carrier 7 has arrived on the 0th track of 1A1-A01, and
sends a coincidence signal to the information processing control device 2o. The information processing control device 2o transmits a signal to stop the linear motor 13 to the drive control circuit 19, short-circuits the switch 15, and operates tracking control and transport control, so that the light beam 2 on the record carrier 7 is positioned. Address A of the truck
2 (hereinafter this search will be referred to as a coarse search). Ao
If =A2, the search ends, but if lA2-Aol≧N, the above-mentioned rough search is performed again. Also IA2~
If A, l(N), the information processing control device 20 opens the switch 15, sends a signal to the drive circuit 17, drives the tracking element 10, shorts the switch 15 again, and performs one trunk interlaced scan ( This scanning is hereinafter referred to as jumping.) After repeating this jumping once, the light beam 2
The address A3 of the track where is located is read (hereinafter, this search will be referred to as a dense search (0)). If it is Ao-A3, the search ends, but Ao arrow A3 (Ao to A3 is 80 and A3
represents that they are not equal. ), the coarse search and fine search described above are repeated to search for the desired track.

By the way, when recording digital information on a track on the record carrier 7, since the length of the information is undefined, it is advantageous to record the 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 during recording and playback (sector number), a sector seven-folder area is provided at the beginning of each sector, and the track is provided with a seven-round sector area. One or more address signal recording areas (hereinafter referred to as address areas) are provided in each area in advance.

An example of such a record carrier is shown in FIG.

The record carrier 7 in FIG. 2 has a sector area 81 for recording information.
~S32, sector separator areas SP1-5P32 separating each sector area, and address area TA1. It is composed of TA2.

FIG. 3a shows the sector area S1 of the track 22 in FIG.
, sector separator area SP1, and address area TA1.
FIG. 3 is a plan view of the disk along the track of FIG. The depth of the track is δ, the width of the groove is W, and δ
is about % of the wavelength λ of the laser beam to make it easier to obtain a tracking signal, and W is about 0.6 μm to increase the density.
, the address area TA1 (same as TA2), and the sector separator area 5P1 (same as S P2 to 5P32) are provided with information on the presence or absence of grooves on the disc in advance, and are created at the same time when cutting the grooves.

Therefore, it is necessary to perform the above-mentioned search in a short time, and in order to perform a high-speed search, it is necessary to drive the linear motor 13 and move the transfer table 12 at high speed in the direction of the desired track. However, when the record carrier 7 having the structure described above is used, 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. the differential amplifier 14 in FIG.
The output signal, that is, the tracking signal, is one cycle of 8
This results in a signal waveform of the shape of a letter (Fig. 4b). However, in the address area or sector separator area, the reflected light is affected by diffraction due to the address information or sector separator information (uneven pits) created on the track, as shown in Figure 6a, and the tracking signal is disturbed. Figure 5 b).

The track crossing detection circuit 22 in FIG.
4, the tracking signal is waveform-shaped and the drive control circuit 19
to communicate. The counting circuit included in the drive control circuit 19 is
The signal from the track crossing detection circuit 22 is counted, but as mentioned above, it is not possible to accurately count the tracks crossed by the beam in the sector separator area or the address area due to the influence of uneven focusing. Therefore, coarse searches had to be performed many times, making it difficult to perform high-speed searches.

OBJECTS OF THE INVENTION An object of the present invention is to provide an apparatus which eliminates the above-mentioned conventional drawbacks and can search for a desired track at high speed and stably.

Structure of the Invention The present invention provides a recording device 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 dividing the track. a carrier, a converting means for reproducing or recording a signal from a track 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 for moving the scanning position of the converting means including the first moving means in a direction substantially perpendicular to the track direction on the record carrier; a control means for driving and controlling the first moving means so that the first moving means is always on the trunk of the record carrier; a light detection means for detecting an address area or a sector separator area of the record carrier; and a track on the record carrier. 7. Count the output signal of the converting means that crosses the 7. a counting means; a switching means controlled by a detection signal from the light detection means;
It has a phase comparison means and a frequency generation means, and the output signal of the conversion means inputted via the switch means and the output signal generated by the frequency generation means is detected by the phase comparison means. The structure is such that the phases are compared, the frequency generating means generates a frequency corresponding to the phase error signal, and the output signal of the frequency generating means is counted as a track crossing signal by the counting means.

Description of examples The present invention will be described in detail below with reference to the drawings.

FIG. 6 shows one embodiment of the present invention, and in explaining FIG. 6, parts that overlap with those in FIG. 1 will be briefly explained.

61 is a light source, 52 is a light beam, 53 is a coupling lens, 54 is a beam splitter, 55 is a reflecting mirror, 66 is a converging lens, 57 is a record carrier, 58 is a motor, and 59 is a photodetector with a two-part structure. .

Each signal from the photodetector 59 is input to a differential amplifier 64. The signal from the differential amplifier 64 is input to a trunk crossing detection circuit 72 and a switch 65, and the output of the switch 65 is input to phase compensation circuits 66 and 68. The signal from the phase compensation circuit 66 is input to the drive circuit 67, and the signal from the drive circuit 67 is input to the tracking element 60.

The signal from the phase compensation circuit 68 is input to a drive control circuit 69 for driving and controlling the linear motor 63, and the signal from the drive control circuit 69 is input to the linear motor 63, respectively. A signal from the speed detector 61 that outputs a signal corresponding to the moving speed of the transfer table 62 is input to a drive control circuit 69 and a track crossing detection circuit 72, respectively. The photodetector 73 is the second
The address areas (TA1, TA2) and sector separator areas (sp1 to 5P32) of the figure recording body 57 are detected, and the track crossing detection circuit 72
The two signals are input to the drive control circuit 69, respectively.

Further, the address input device 71 is used to input information necessary for a search, and the signal from the address input device 71 is input to the information processing control device 7Q. The information processing control device 7o is used to control the switch 66, the drive circuit 67, and the drive control circuit 69 as necessary.

FIG. 7 shows a specific example of the trunk crossing detection circuit 72 of FIG. 6, where a is a signal output from the differential amplifier circuit 64 of FIG. 6 and is input to low-pass filters 74 and 76.

Cutoff frequency f of low-pass filter 74. 1 and
The relationship between the cutoff frequency f of the low-pass filter 76 is f. 1〈fo2 and 2. The signal from the low-pass filter 74 is transmitted to the switch 82 via a comparator 75 which converts it into a binary signal, and the signal from the low-pass filter 76 is transmitted via a comparator 77 which converts it into a binary signal. Switch 78, phase comparison circuit 79
, low-pass filter 80, variable frequency generation circuit 81,
The signal is transmitted to switch 82. The phase comparison circuit 79 compares the phase of the signal input via the switch 78 and the signal generated by the variable frequency generation circuit 81, and the phase error signal is filtered out by a low-pass filter 8o to eliminate high-frequency component noise. removed. The variable frequency generation circuit 81 is a circuit that generates a frequency according to an input signal. Therefore, the signal input to the phase comparator circuit 79 via the switch 78,
The frequencies of the signals generated by the variable frequency generation circuit 81 are the same. b is a signal output from the photodetector 73 in FIG. 6 and is input to the waveform shaping circuit 83. Waveform shaping circuit 8
3 is a switch 7 which shapes the input signal and converts it into a binary signal.
8. C is a signal output from the speed detector 61 in FIG. 6 and is input to the comparator 84. Comparator 84
When the speed of the transfer table 62 increases, the output signal becomes a HiGH state and is transmitted to the switch 82. If the output signal of the comparator 84 is in the Low state, the switch 82 selects the output signal of the comparator 75 and outputs it to d. i! When the output signal of the comparator 84 becomes HiGH, the variable frequency generating circuit 8
1 is selected and output to d. The output of the switch 82 is transmitted to the drive control circuit 69 shown in FIG.

Next, search will be explained. Address A of the desired track in the address input device 71. When input, the information processing control device 7o reads the address A1 of the track where the light beam 52 is currently located, and calculates (A1-A.). IA
If l-Ao1≧N (IAl-Aol represents the absolute value of (A1-Ao), and N is a positive integer), the information processing control device 7o drives and controls the value of IAl-Aol and the direction signal. The circuit 69 presets the value of IAl-Aol in the counting circuit included in the feed drive control circuit 69, and at the same time opens the switch 66 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 the desired trunk exists. The signal from the differential amplifier 64 is input to a track crossing detection circuit 72, and the signal from the track crossing detection circuit 72 is input to a drive control circuit 69. When the transfer stage 62 moves in the radial direction of the record carrier 57, a signal generated by the light beam 52 on the record carrier 57 crossing the track is outputted from the differential amplifier 64, and a low-pass filter 74 removes the high-frequency components. Noise is removed, the signal is binarized by a comparator 75, and the signal is transmitted to a switch 82. When the moving speed of the transfer table 62 is slow (i.e., the start of acceleration or
Immediately before stopping), the signal of the speed detector 61 is low, so the output of the comparator 84 is in the Low state, and the switch 82 sends the signal of the comparator 76 to the drive control circuit 69 because the signal of the comparator 84 is in the Low state. A counting circuit included in the drive control circuit 69 counts the signal input via the switch 82 . When the light beam 52 crosses the sector separator area or address area on the record carrier 67 as shown in FIG. 8a, the output signal waveform of the differential amplifier 64 becomes as shown in FIG. FIG. 8C shows the waveform of the output signal of the low-pass filter.

Next, when the moving speed of the transfer table 62 becomes faster, the speed detector 6
1 becomes high, the output of the comparator 84 becomes HiGH state, and the switch 82 transmits the signal of the variable frequency generation circuit 81 to the drive control circuit (39) to control the drive. A counting circuit included in the circuit 69 counts the signals inputted through the switch 82. Here, when the light beam 52 traverses the sector separation 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. The signal waveform of the low-pass filter 76 is shown in FIG. 9a, and the signal waveform of the comparator 77 is shown in FIG.
The photodetector 73 detects the signal waveform of the record carrier 57.
is on a straight line connecting the center of rotation of the light beam 62 and the position of the light beam 62 converged on the record carrier 7, and if the light beam 62 is in the address area on the record carrier, then the photodetector] is also located on the record carrier. The photodetector 73 is arranged in advance so that when the light beam 62 is in the sector separator area, the photodetector 73 also irradiates the entire sector separator area on the record carrier.

Thus, when the light beam 62 traverses the sector separator area or address area on the record carrier 67, the photodetector 73
Similarly, the sector separator area or address area is detected. The waveform shaping circuit 83 shapes the waveform of the signal from the photodetector 73 and makes it H in the sector separator area or address area.
In the iGH state and other areas, the signal is binarized so as to be in the Low state and transmitted to the switch 78. This signal waveform is shown in FIG. 9C.

The switch 78 is configured so that the output signal of the waveform shaping circuit 83 is Low.
When the state is high, the switch is turned on and the output signal of the comparator 77 is transmitted to the phase comparison circuit 79, but when it is in the Hi GH state, the switch is turned off and the output signal of the comparator 77 is transmitted to the phase comparison circuit 79.
This situation is shown in FIG. 9d. The phase comparison circuit 79 compares the phases of the signal input from the switch 78 and the signal input from the variable frequency generation circuit 81 and transmits the phase error to the variable frequency generation circuit 81 via the low-pass filter 80. However, switch 7
When the signal input from 8 is missing, the previous phase error is held. The variable frequency generating circuit 81 generates a frequency according to the phase error inputted through the low-pass filter 80 and transmits it to the switch 82 . Therefore, even if the signal input via the switch 78 is absent, the variable frequency generating circuit 81
The output signal of is interpolated. FIG. 9e shows a signal waveform of the variable frequency generating circuit 81.

Therefore, even if the moving speed of the transfer table 62 is increased and the light beam 52 crosses a sector separator area or an address area on the record carrier, it is possible to accurately detect that the light beam 52 has crossed a track.

A counting circuit included in the drive control circuit 69 counts the interpolated signal of the track crossing detection circuit 72 and
Detecting that the upper light beam 52 has come onto the 0th track of the first IAl-A0, the drive control circuit 69 sends a coincidence signal to the information processing control device 7o.

The information processing control device To transmits a signal for stopping the linear motor 63 to the drive control circuit 69, short-circuits the switch 65, operates tracking control and transport control, and determines the position of the light beam 52 on the record carrier 67. Read address A2 of the trunk. If Ao=A2, the search ends, but if lA2-Ao1≧N, the above-mentioned rough search is performed again. If lA2-A21<N, the information processing control device 70 opens the switch 66, sends a signal to the drive circuit 67, drives the tracking element 6°, and shorts the switch 16 again, thereby completing one jump. and perform this jumping to lA2
- After repeating A01 times, read the address A3 of the trunk where the light beam 2 is located.

If Ao-A3 is -, the search ends, but AoNA3
If so, the coarse search and fine search described above are repeated to search for the desired track.

Effects of the Invention According to 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 trunk traversal signal, and the search can be performed in a short time. Reliability can be significantly improved.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of a conventional optical recording/reproducing device, Fig. 2 is a plan view schematically showing each area on a disk, and Fig. 3a is a plan view showing an address area and a separator area. , FIG. 3 is a sectional view of the same, FIG. 4, FIG. 5, and FIG. 8 are diagrams showing the relationship between the optical spot and the track and tracking waveforms during jumping, respectively, and FIG. 6 is an embodiment of the present invention. FIG. 7 is a block diagram showing details of the track crossing detection circuit in the same embodiment, and FIG.
The figure is a waveform diagram showing the output waveform at each point in FIG. 7. 51...Light source, 66...Tracking element, 67...Record carrier, 64...Differential amplifier, 2...Track crossing detection circuit, 69・・・
・・Drive control circuit, 63・・Linear motor, 73・
...Photodetector, 74°78.80 ...Low pass filter, 75,77°84...Comparator, 78.8
2... Switch, 83... Waveform shaping circuit, 79
...Phase comparison circuit, 81...Variable frequency generation circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 4 Figure 5 4 days 4 days r 7L/1 Figure 6 Figure 8 mouth bsu Figure 9 +b+ [C1 (d] (e)

Claims (1)

[Claims] 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 dividing the track, and this record carrier. a converting means for reproducing or recording a signal from an upper track; 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 scanning position of the converting means. a second moving means that moves the first moving means in a direction substantially perpendicular to the track direction on the record carrier; and a scanning position of the converting means is always on the track on the record carrier. a control means for driving and controlling the first moving means, a light detection means for detecting an address area or a sector separator area of the record carrier, and a converting means for traversing the tracks on the record carrier. It has a counting means for counting output signals, a switching means controlled by the detection signal of the photodetecting means, a phase comparing means, and a frequency generating means, and the trunk input via the switching means is The phase comparison means compares the phases of the output signal of the transverse conversion means and the output signal generated by the frequency generation means, and the frequency generation means generates a frequency corresponding to the phase error signal. An information track retrieval device characterized in that the output signal of the generating means is configured to be counted by the counting means as a track crossing signal.