JPH08306048A - Truck counter - Google Patents

Abstract

(57) [Summary] [Purpose] Even if there is dirt such as fingerprints on the card surface, accurate seek operation is possible and the access time to a desired track can be shortened. A record carrier 107 having a plurality of tracks T1, T2, a light beam generating means 106 for generating a light beam, and a moving means 301 for relatively moving the record carrier or the light beam generating means in a direction perpendicular to the track direction, In the track counting device provided with signal generation means 109 and 408 for generating a signal according to the light quantity of the reflected light obtained by irradiating the record carrier with the light flux obtained from the light flux generation means, the output of the signal generation means by the movement means Is binarized by n (n ≧ 2) binarizing means having different binarizing levels, and the transition direction of n + 1 level regions divided by the n binarizing means is determined. Means and counting means for counting when the transition direction changes are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a track counting device for counting the number of tracks from a track crossing signal in an information recording / reproducing device using a record carrier such as an optical card or an optical disk having a plurality of tracks.

[0002]

2. Description of the Related Art Conventionally, as a form of a recording medium for recording information by using light and reading the recorded information,
Various types such as a disk shape, a card shape, and a tape shape are known. These optical information recording media include those that can be arbitrarily recorded and reproduced, those that can be additionally recorded and reproduced, and those that can only be reproduced. In particular, it is considered that the optical card as a recording medium will be widely used because of its features such as ease of manufacture, portability, and accessibility. Various optical information recording / reproducing devices for this optical card have been provided.

In such an optical information recording / reproducing apparatus, information is recorded / reproduced while always performing auto-tracking and auto-focusing control. Recording of information on a recording medium is performed by scanning an information track with a light beam that is modulated according to the recording information and focused into a minute spot, and a series of information is formed as an optically detectable information pit string. Will be recorded. Furthermore, when reproducing information from a recording medium, the information pit row of the information track is scanned with a light beam spot having a constant power of such a low power that recording is not performed on the medium, and reflected light from the medium, or This is done by detecting transmitted light.

FIG. 12 is a block diagram showing a typical example of such information recording / reproducing system. In the information recording / reproducing apparatus shown in FIG. 12, the luminous flux of the semiconductor laser 101 is collimated by the collimator lens 102, and this collimator lens 102 collimates the luminous flux.
At 3, it is divided into a plurality of light beams. Then, the split light flux is transmitted to the polarization beam splitter 104 and the quarter wavelength plate 10.
5, the light is further focused on the optical card 107 via the objective lens 106. Then, the reflected light from the optical card 107 enters the photodetector 109 via the objective lens 106, the quarter-wave plate 105, the polarization beam splitter 104, and the toric lens 108. Thus, the photodetector 10
According to the detection signal detected by 9, the diffraction grating 103
Recording, reproduction, and autofocusing control (hereinafter, referred to as AF) are performed by using the 0th-order diffracted light of the light beams divided by, and auto-tracking control (hereinafter, referred to as AT) is performed by using the ± 1st-order diffracted light. Is performed. AF
Is an astigmatism method, and AT is a three-beam method.

FIG. 13A is a schematic plan view of an optical card. A large number of information recording / reproducing tracks are arranged in parallel on the optical card 107.
2, T3 ... This track is divided into tracking tracks tt1 to tt4. The tracking tracks tt1 to tt4 are formed of a material having a light reflectance different from that of the grooves or the tracks T1 to T3, and are used as guides for obtaining a tracking signal.
FIG. 13A shows an example of recording or reproducing information on the track T3. In this example, recording, reproduction, A
The 0th-order diffracted light 110 for F is on the track T3,
The first-order diffracted lights 111 and 112 are tracking tt3 and
It is irradiated at tt4. Then, the diffracted light 111, 11
A tracking signal, which will be described later, is obtained by the reflected light from 2, and the 0th-order diffracted light 110 is controlled so as to correctly scan the track T3. Each diffracted light 110, 111, 112
Under the AF and AT, the optical card 107 is scanned left and right in the drawing by a mechanism (not shown) while maintaining the same positional relationship.

This scanning system includes a system for moving an optical system and a system for moving an optical card. In either system, since the optical system and the optical card reciprocate relative to each other,
Some parts of the optical card do not have a constant speed. This is shown in FIG. 13 (B). The horizontal axis of FIG. 13B represents the horizontal direction of the optical card, and the vertical axis represents the relative scanning speed between the optical system and the optical card. Usually an optical card 1
The constant speed scanning area at the center of 07 is used as a recording area.

FIG. 14 shows the diffracted lights 110 to 110 of FIG.
FIG. 11 is a partially enlarged view of 112. The 0th-order diffracted lights 110 for recording, reproduction, and AF are ± first-order diffracted lights 111 and 112 for AT.
The center of the track T3 is scanned. The shaded portions 113a, 113b, 113c are recording lines by the 0th-order diffracted light 110 due to the strong power of the semiconductor laser 101, and are generally called pits. Since the pits 113a, b, and c have different reflectances from the periphery of the recording row other than, the weak light spot 1
When scanning at 10, the reflected light of the 0th-order diffracted light 110 is pit 1
A reproduced signal is obtained by being modulated with 13a, 13b, 13c. Further, the ± first-order diffracted lights 111 and 112 for AT are applied to the periphery of the recording row and the tracking tracks tt3 and tt4,
A tracking signal is obtained by the reflected light.

FIG. 15 shows the photodetector 109 shown in FIG.
3 is a circuit diagram showing the details of FIG. 1 and a signal processing circuit. In the figure, the photodetector 109 is composed of a four-division photosensor 114 and a total of six photosensors 115 and 116. In addition, the light spots 110a, 111a, 112a
Is the diffracted light 11 in FIG. 13 (A) and FIG. 14, respectively.
It represents the reflected light of 0, 111, and 112. Light spot 11
0a is condensed on the four-division optical sensor 114, and the light spots 111a and 112a are condensed on the optical sensors 115 and 116, respectively. The sensor outputs in the diagonal directions of the four-divided sensor 114 are added by the adder circuits 117 and 118, respectively.

The outputs of the adder circuits 117 and 118 are similarly added by the adder circuit 121 and reproduced as an information reproduction signal RF. That is, the information reproduction signal RF is transmitted to the four-division optical sensor 11
This corresponds to the total sum of the light spots 110a focused on the beam No. 4.
Further, the outputs of the adder circuits 117 and 118 are subtracted by the differential circuit 120 and become the focusing control signal Af. That is,
The focusing control signal Af is the difference between the sums of the four-division optical sensor 114 in the diagonal directions. Since this astigmatism method is detailed in the literature, its explanation is omitted here.

The outputs of the optical sensors 115 and 116 are
The tracking control signal At is subtracted by the differential circuit 119.
Becomes Normally, the tracking control signal At is controlled so as to be zero, whereby tracking control for scanning the light spot by following the information track is performed.

The target track T on the optical card 107 is also
1, T2, T3, ... In order to access the optical spot, the optical head and the optical head which emit a light beam by detecting a track crossing pulse generated when the light spot crosses a track on the optical card and performing a track count. A method is used in which the tracks on the card are moved relative to each other at a right angle.

Conventionally, as a method of detecting a track crossing pulse, a tracking control signal At is compared with a constant voltage V _L by a comparator and binarized.
FIG. 16A is a signal waveform diagram showing the relationship between the At signal and the track crossing pulse TRC which is a binarized output thereof by such a conventional method.

In FIG. 16A, the At signal waveform 1
Since the TRC1 pulse is output as a wave, the relative movement distance between the optical spot and the optical card can be measured by counting the TRC pulse, so that the optical spot can access the target track.

[0014]

However, in the above-mentioned conventional example, it is difficult to accurately output the track crossing pulse with respect to the fluctuation of the tracking control signal At signal due to stains such as fingerprints on the surface of the card. Therefore, there may be an error in the track crossing count,
It was difficult to accurately detect the relative movement distance between the light spot and the optical card.

FIG. 16B shows the relationship between the fluctuation of the tracking control signal At signal due to a fingerprint or the like on the card surface and the TRC signal which is a binarized output.
Since the voltage V _L that is a constant level is compared, the level b does not become lower than the voltage V _{L in the} tracking control signal At signal, so that no pulse corresponding to the waveform b is generated as the TRC output. As described above, if the amplitude of the At signal fluctuates and the level of the tracking control signal At signal fluctuates due to stains such as fingerprints on the card surface, it is difficult to perform cross-track counting.

FIG. 17 shows that the comparator disclosed in Japanese Patent Laid-Open No. 2-54429 has hysteresis.
It is a waveform obtained by comparing the tracking control signal At signal. Here, the tracking control signal At signal is VH
When the voltage exceeds the level, the comparator output becomes "H", and when it becomes lower than the VL level, the comparator output becomes "L" level to remove noise and the like added to the tracking control signal At signal.

In this case, if the voltage V _H <At is H level, the voltage V _L ≤At ≤V _H is M level, and At <V _L is L level, the comparator output is "H" when At is H level. ", At is L level, it is" L ", but when the peak-peak value of the tracking control signal At is M level, it may be" H "or" L ".

As described above, the above-mentioned conventional example is considered to have two binarization levels of H and L levels, but when an abnormality occurs in the reflectance of the optical card such as fingerprints and dust on the card surface, Cannot obtain an accurate binarized signal and cannot scan an appropriate track by counting the binarized signal.

Therefore, a first object of the present invention is to accurately count the number of track crossings, which is used for detecting the number of track crossings, even if the amplitude and level of the reflected signal from the record carrier fluctuate. .

A second object of the present invention is to eliminate the influence of noise generated in the signal used for track crossing detection due to electrical or optical reasons.

A third object of the present invention is to simplify the hardware structure when binarizing a plurality of levels.

A fourth object of the present invention is to eliminate in-phase noise input to each sensor by using a differential signal and perform more accurate track crossing counting.

[0023]

In order to achieve the above object, a first aspect of the present invention provides a record carrier having a plurality of tracks, means for generating a light beam, and the plurality of tracks. Reflection from the record carrier obtained by irradiating the record carrier or a means for generating a light beam relative to the direction perpendicular to the track direction and a light beam obtained from the means for generating a light beam to the record carrier In a track counting device provided with means for generating a signal according to the amount of light, by moving a record carrier having a plurality of tracks or a means for generating a light beam relatively in a direction perpendicular to the track direction, The n (n) signals having different binarization levels are provided according to the amount of reflected light generated when the light beam applied to the record carrier crosses the track.
≧ 2) binarized by the binarizing means and determining the transition direction of the n + 1 level regions divided by the n binarizing means, and means for counting when the transition direction changes. It is characterized by doing.

In the above structure, the binarizing means divides the signal corresponding to the light quantity of the reflected light generated when the light beam applied to the record carrier crosses the track into n + 1 level areas, and the transition direction determining means determines the level area. The counting means operates to determine a transition direction, that is, a direction in which the level increases or decreases, and the counting means counts when the transition direction changes from increase to decrease or decrease to increase.

A second invention according to the present invention is the above-mentioned 2
The digitizing means is characterized by having hysteresis.

In the above structure, 2 having hysteresis
The quantizing means operates so as to remove noise generated in the signal corresponding to the reflected light generated when the light beam applied to the record carrier crosses the track.

A third invention according to the present invention is characterized in that the binarizing means is an A / D converter and a digital value comparing means. In the above configuration, the A / D converter is:
A signal corresponding to reflected light generated when a light beam applied to a record carrier crosses a track is A / D converted into a digital value, and the value and a digital binarization level are compared by a digital value comparison means. To work.

A fourth invention according to the present invention is characterized in that the luminous flux is two luminous fluxes having a phase shift, and a difference signal generating means is provided, and the difference signal output is binarized in the above-mentioned configuration. Operate.

According to a fifth aspect of the present invention, the record carrier having the plurality of tracks or means for generating a light beam is moved relative to the direction perpendicular to the track direction to irradiate the record carrier. A feature of the present invention is that a signal corresponding to the amount of reflected light generated when a light beam crosses a track is detected by using an A / D converter, and track crossing count is performed based on the detected value.

In the above structure, the A / D converter detects a signal corresponding to the light amount of the reflected light generated when it crosses the track, detects a peak based on the detected value, and changes the first predetermined amount from the peak value. It operates so as to perform track crossing count at the detected point.

A sixth invention according to the present invention uses the same means as the fifth invention, and in the configuration, the A / D converter detects a signal in accordance with the amount of reflected light generated when the track crosses. When performing, the peak detection is performed based on the value that has changed by the second predetermined amount or more from the value detected and stored previously, and the track crossing count is performed at the detection point where the first predetermined amount changes from the peak value. It works as it does.

A seventh aspect of the invention is characterized in that two light fluxes having different phases are used as the light flux for irradiating the record carrier, and a difference signal between them is used.

In the above structure, the difference signal is detected by the A / D converter, the peak is detected based on the detected value, and the track crossing operation is performed at the detection point where the peak value changes by the first predetermined amount. .

[0034]

【Example】

(First Embodiment) FIG. 2 is a block diagram of a track counter 407 and an AT / AF control circuit 405 according to an embodiment of the present invention.

The tracking control signal A differentially output from the detection signals of the optical sensors 115 and 116 shown in FIG.
The focusing control signal Af differentially output from t and the detection signal at each intersection of the four-division sensor 114 is input to the AT / AF control circuit 405 in FIG. The Af signal is input to the phase compensator 201 and the binarizing means (comparator) 216. A in the comparator 216
A signal obtained by binarizing the f signal is input to the MPU 217. The output of the phase compensator 201 is input to the W terminal of the switching SW202. The switching SW 202 selects the W terminal or the X terminal according to the switching signal from the MPU 217. A constant voltage is input to the X terminal. The signal selected by the switch SW202 is AF
The AF coil 204 of the actuator is driven via the coil driver 203 and moved in the direction perpendicular to the surface of the storage medium for focusing by the objective lens 106.

The At signal is input to the phase compensator 205, and the binarized signal is input to the MPU 217 via the comparators 213, 214 and 215. Phase compensator 20
The output of 5 is input to the Y terminal of the switching SW 206.

On the other hand, a light beam of an LED (not shown) provided on the movable head 301 is reflected by a reflection plate provided on the side surface of the lens barrel of the objective lens 219, and a pair of position sensors 219a,
Input to 219b. The output signals pA and pB of the position sensors 219a and 219b are input to the differential amplifier 218. The lens position signal PST, which is the output of the differential amplifier 218, is input to one end of the differential amplifier 210 and the MPU is connected to the other input terminal.
The output of 217 is connected via the D / A converter 212.

The output of the differential amplifier 210 is input to the phase compensator 211, and the output of the phase compensator 211 is switched SW2.
Input to the Z terminal of 06. Switch SW206 is MPU21
Either a tracking servo state (Y terminal side) or a lens position servo state (Z terminal side) can be selected by a switching signal from 7. The output of the switching SW 206 is input to the AT coil driver 207 to perform power amplification to drive the AT coil 208 of the AT actuator, and the objective lens 10
6 can be moved at right angles to the track.

The track counter is a companator 21.
3, 214 and MPU 217.

FIG. 4 is a block diagram showing an embodiment of an optical card recording / reproducing device using the AT / AF control circuit and the track counting device shown in FIG.

The outline of the optical card recording / reproducing apparatus will be described with reference to FIGS. 2 and 4. First, when the optical card 107 is inserted into the device, it is detected by a sensor (not shown), and the MPU2
17 drives the loading motor 402 via the motor drive circuit 401, introduces the optical card 107 into the apparatus, and mounts it on the carriage 403.

A light beam emitted by the semiconductor laser 101 in the fixed head 304 driven by the laser drive circuit 404 instructed by the MPU 217 enters the movable head 301, and the objective lens 106 causes the optical card 107 on the carriage 403. Focus on. Using the AF coil 204 on the movable optical head 301, the AT pull-in and auto-focusing control are performed by the AT / AF control circuit 405 which receives a command from the MPU 217 to focus the light beam on the recording / reproducing surface of the optical card 107.

Details of the AF pull-in are shown in FIGS. 2, 14, and 15.
Will be explained. Of the light beam reflected by the optical card 107, the light spot 110a that is the center light is detected by the four-division sensor 114, and the focusing control signal Af is detected.
Is monitored by the MPU 217 via the comparator 216.

When the AF pull-in is started, a switching signal is given from the MPU 217 to the switching SW 202 to switch to the X terminal side.
Set to F pull-in mode. A constant current flows through the AF coil, and the objective lens 106 moves in the direction perpendicular to the medium surface.

Then, in the MPU 217, the comparator 2
16 outputs are detected. This comparator 216 is AF
A signal is output at the in-focus point, and at this timing, a switching signal is sent from the MPU 217 to the switching SW 202 to switch to the W terminal side and the AF servo mode is set. With this, the auto-focusing state is set.

The AF lead-in is performed when the light spot is on the track of the recording / reproducing medium.

Next, an AT / AF control circuit 405 receives an instruction from the MPU 217 to track the track on the optical card 107 by using the AT coil 208, which is the first driving means on the movable head 301, to pull in the AT. And auto-tracking.

Details of the AT pull-in will be described with reference to FIG.
When the AT pull-in is started, a switching signal is given from the MPU 217 to the switch SW 206 to switch to the Z terminal side, and the AT pull-in mode is set. The lens position signal PST which is the output of the differential amplifier 218 and the signal obtained by differentially amplifying the output of the D / A converter 212 instructed by the MPU 217 by the differential amplifier 210 are used as the phase compensator 211 and the AT coil driver 2
07, a lens position servo is formed via the AT coil 208, and the output of the D / A converter 212 is gradually changed to make the objective lens perpendicular to the track on the card 107 (direction crossing the track). Move slowly to.

On the other hand, the tracking control signal At is monitored by the MPU 217 via the comparator 215 and turned on.
At the time of tracking, a switching signal is sent from the MPU 217 to the switching SW 206 to switch to the Y terminal side, and the AT servo mode is set. As a result, the automatic tracking (AT) state is set.

Next, the magnet 409 and the voice coil 41
MPU for voice coil motor of magnetic circuit composed of
The output of the head drive circuit 411 which receives the command from 217 is input, and the movable optical head 301 is scanned, that is, the light beam is scanned.

The information reproduction signal RF detected during the scanning is input to the reproduction circuit 412 to reproduce the information written on the optical card 107 and input to the MPU 217. Optical card 1
Track ID No. indicating the track position on the optical card among the information written on the track No. 07. The current position of the light beam can be known from.

Next, after the light spot is positioned at the left end or the right end of the entire scanning area of FIG. 13B, the MPU 217
A switching command is sent to the switching SW 206 to switch to the Z terminal. The output of the D / A converter 212 is kept constant, and the position of the objective lens 209 is kept constant with respect to the movable head 301.

Next, the MPU 217 issues a drive command to the carriage drive circuit 406 to drive the carriage 403 in the direction perpendicular to the track. At this time, the MPU 217 detects the outputs of the comparators 213 and 214 and counts the number of traverse tracks where the light beam traverses the tracks on the optical card.

FIG. 3 is a diagram showing the tracking control signal At and the output signals TRCU and TRCL of the comparators 213 and 214 when the light beam crosses a track on the optical card. It shows that the amplitude and level of the At signal are changed.

FIG. 3A shows the case where the optical card 107 on the carriage 403 moves in the FWD direction together with the carriage 403, and FIG. 3B shows the REV direction.

In FIGS. 3A and 3B, the output obtained by comparing the tracking control signal At with the level Vu is T.
RCU and the tracking control signal At is at the level Vu.
At the above time, TRCV is set to "H" level. Further, the output obtained by comparing the tracking control signal At with the level V _L is TRCL, and the tracking control signal At is V
TRCL outputs "H" level when _L or more.

In FIG. 3A, the light beam starts moving from point A, TRCU goes from L to H at point B, and goes from H to L at point C. Next, at point D, TRCL becomes H
→ L, then L → H at point E. The same operation is performed thereafter to output TRCU and TRCL to the MPU 217. Note that L → H will be referred to as U (UP), and H → L will be referred to as D (DOWN).

FIG. 1 is a flow chart showing the counting method of the track counting device of the present invention. Description will be given with reference to FIG.

Track counting is started in step ST1. Since the moving direction is known depending on the case of recording or reproducing by the MPU 217 which instructs the carriage drive circuit 406, the moving direction is branched at step ST2, and when it is the FWD direction, F is stored in the DIR register at step ST3. To do. When it is in the REV direction, step S
At T4, R is stored in the DIR register. This time FWD
Since it is the direction, F is stored in the DIR register.

Next, at step ST5, the CNT register indicating the track count value is cleared, and the FLAG register indicating the first comparator detection is cleared to store φ.

The rising or falling edge of the output TRCU of the comparator 213 and the output TRCL of the comparator 214 is detected in step ST6, and it is judged in step ST7 whether the edge detected in step ST6 is a rising edge or a falling edge and branched. In step ST8 or step ST9, the type of edge is stored in the UD register. That is, U is temporarily stored in the UD register at the time of rising and D is stored at the time of falling. This time, starting from point A, the first edge is detected at point B, and since it is a rising edge, U is stored in memory.

Next, in step ST10, it is determined whether or not the content stored in the FLAG register is φ. This time step S
Since it is φ at T5, it branches to Y. Branches to Y only at the first edge from the start of track counting. In step ST11, the MEM register contents U in the MEM register
Is stored and the value of the FLAG register is set to 1.

In step ST12, it is compared whether or not the numerical value of the CNT register is the desired track count value N. Since CNT = φ (≠ N) this time, the process returns to step ST6.

The light beam further moves, and TRC is made at point C.
U becomes the D edge. Therefore, D is stored in the UD register in steps ST7 and ST9.

In step ST10, since FLAG = 1 thereafter, the flow always branches to N. Next, in step ST13, the contents of the MEM register and the contents of the UD register are compared, and if they are the same, the process branches to Y, and the process proceeds to step ST12. This time, the contents of the MEM register is U at point C,
Since the content of the UD register is D, it branches to N.

Next, in step ST14, it is determined whether the direction in which the light beam is moving is the FWD direction or the REV direction, and the process branches. The movement direction is already known in steps ST2 to ST4, and this time it is the FWD direction, so the process branches to Y. In step ST15, the process branches depending on whether the content of the UD register is U or not. Since the content of the UD register is D this time, the process proceeds to step ST18. In step ST18, the contents of the UD register are stored in the MEM register. This time, D is memorized. From step ST12 to step ST6 again
Return to and detect the edge. Next, since the trailing edge is detected at point D, D is stored in the UD register in step ST9, and the process proceeds to steps ST10 and ST13.

At step ST13, the MEM register and U
Since the contents of the D register are the same, branch to Y, and then step S
After T12, the process returns to step ST6 again.

Next, U is stored in the UD register at point E, and steps ST10, ST13 and S are executed.
The process proceeds to T14 and step ST15. In step ST15, since the UD register is U this time, the process branches to Y, and the CNT register is incremented in step ST17. This time CNT goes from 0 to 1. In step ST18, U, which is the content of the UD register, is stored in the MEM register, and after step ST12, step ST6 is executed again.
Return to Thereafter, similarly, the count number of the CNT register is incremented, and when the predetermined count N is reached in step ST12, the process branches to Y, and the track count process ends.

FIG. 3A shows the contents U and D of the UD register and the count values φ, 1, 2, ... Of the CNT register. In this way, as shown in FIG.
The waveform of b that was raised due to fingerprints and the like could not be counted, but it is possible in the present invention.

FIG. 3B shows the case where the optical card moves in the REV direction, and according to the flowchart of FIG.
Track counting can be performed as in the case of FIG. The feature of the present invention is that in the FWD direction, the track crossing count is performed when the level transition direction is D → U, and in the REV direction, the track crossing count is performed when the level transition direction is U → D. That's what I did.

(Second Embodiment) FIG. 5 is a signal waveform diagram showing a second embodiment of the present invention. The comparator 21 of FIG.
An example is shown in which an optical card is moved in the FWD direction by using a comparator having hysteresis in 3,214.
That is, as shown in FIG. 5, when the waveform of the tracking control signal At is a waveform including a minute amplitude due to electrical noise or the like, minute fluctuations occur in the TRCU and TRCL signals,
Although it becomes difficult to perform accurate counting, the comparators 213 and 214 have hysteresis so that TRCU is set to H and level V _UL is set when the tracking control signal At signal exceeds the level V _UH from a low level to a high level. By setting TRCU to L when the level goes from the high level to the low level, TRCL to L when the level V _LL goes from the high level to the low level, and H when the level V _LH goes from the low level to the high level. The influence of the above noise can be eliminated. The same applies when there is a partial return portion R for optical reasons.

TRCU and TRC thus obtained
Even if the L signal is used, according to the flowchart shown in FIG.
Crossing tracks can be counted in the same manner as in the first embodiment.

(Third Embodiment) FIG. 6 is a signal waveform diagram showing a third embodiment, which is the comparator 21 shown in FIG.
An example in which another comparator is further added to 3,214 and the output compared with the level V _M is set as TRCM is shown.

FIG. 6 shows an example in which the moving direction of the optical card is FWD. In the case of the tracking control signal At waveform as shown in FIG. 6, the waveform of the portion C cannot be track counted only with the comparison levels V _U and V _L. Therefore, by setting the comparator of the added comparator to V _M and providing the level between V _U and V _L as shown in FIG. 6, the cross-track counting of the waveform C becomes possible.

More generalizing this, an accurate track count can be obtained by providing a plurality of comparator levels such that at least one comparator level exists between all the adjacent maximum values and minimum values of the waveform of At. You can do it.

Here, the maximum value and the minimum value are the same as those shown in the second embodiment, and the extreme value between the hysteresis is not considered to be the maximum value and the minimum value. The present invention can also be applied to a tracking control signal At or an At signal having a level return portion R due to optical reasons.

Track counting is performed as described above, the carriage is driven by the carriage driving circuit 406 so that the light beam is positioned on the target track, and tracking pull-in is performed on the target track.
You can enter the playback operation.

Further, in the fourth and fifth embodiments, track counting is performed using the difference signal between two light beams whose phases are shifted, but a single light beam may be used.

In the first, second and third embodiments, when the optical card moving direction is FWD, the value of the UD register is D.
→ Counts when it changes to U, and U when it changes to REV →
Counting when changing to D, FWD, REV
It doesn't matter if you count in either direction.

Further, the value of the UD register is D → U and U →
It suffices to detect both D and count approximately every 1/2 waveform (track).

Further, in the first to third embodiments, the difference signal of two light fluxes whose phases are deviated is compared and used for track counting, but a single light flux may be used.

Further, the comparators of the first to third embodiments are
You may use the A / D converter and the microcomputer means etc. which compare the digital value obtained by the A / D converter with the digital value which is a predetermined comparator level.

(Fourth Embodiment) Regarding the fourth embodiment,
The configuration block diagram will be described with reference to FIG. In the figure, the difference from FIG. 2 described above is that the tracking control signal A
At the input of t, not the comparators 213 and 214 but the A / D converter 220 intervenes in the track counting device 407 between the MPU 217.
That is, the tracking control signal At is transmitted to the A / D converter 2
It is monitored by the MPU 217 via 20 and a switching signal is sent from the MPU 217 to the switching SW 206 when the track is turned on, and the signal is switched to the Y terminal side, the AT servo mode is set, and the movable head 301 is moved to a predetermined track of the optical card.
And the function of the AT coil 208 keeps the objective lens 106 maintained on a regular track. As a result, the automatic tracking (AT) state is set.

The case of moving the track is the same as the example described in the first embodiment, but the MPU 217 detects the output of the A / D converter 220 while the switch SW 206 is switched to the Z terminal side. Light beam is light card 1
Count the number of crossing tracks that crossed the track on 07,
A light beam is irradiated onto a predetermined track. The counting of the number of crossing tracks will be described in detail below.

FIGS. 9A and 9B show how the tracking control signal At is sampled by the A / D converter 220 every Δt time. The movement of the light spot is started from point A, sampling is performed one after another,
In the case of the FWD direction in FIG. 9 (A), the sample positions P1 to P1 after the change from the minimum value by the first predetermined amount C or more.
The track crossing count value is increased at P4. or,
In the case of the REV direction in FIG. 9B, the sample positions P1 to P1 after the change from the maximum value by the first predetermined amount C or more.
The track crossing count value is increased at P4. The value of the CNT register indicating the count value is shown in FIG.
Is shown in the lower part of the tracking control signal At waveform.

FIG. 7 is a flow chart showing the counting method of the track counting device of the present invention. This will be described with reference to the tracking control signal At waveform in the FWD direction of FIG.

In FIG. 7, the track TR count is started in step ST21. In step ST22, the EXT register for storing the extreme value and the CNT register for storing the track crossing count value are respectively set to φ. The value of the tracking control signal At at point A is φ. Next, in step ST23, the relative movement direction DIR of the optical card 107 and the objective lens 106 is known depending on whether the MPU 217 instructing the carriage drive circuit 406 records on the optical card 107 or reproduces it. Therefore, in step ST23, the process branches based on the direction. In the case of FIG. 9 (A), since it is moving in the FWD direction, it branches to FWD. From the above, the moving direction is the FWD direction, so the process proceeds to step ST24, and A1 is set at A1.
The value of the tracking control signal At detected by the / D converter 220 (hereinafter referred to as A1 value) is compared with the value of the EXT register (hereinafter referred to as EXT value), and if "EXT" ≤AD, E
Update the XT value. In Fig. 9 (A), E points up to point A4
The XT value is updated.

Next, in step ST25, "EXT" ≤AD is not established at the value of A5 point, and thus step ST2
Branch to 5. In step ST25, while the AD value is less than or equal to the EXT value, that is, up to A10 point is updated. Then A
At 11 points, AD ≦ “EXT” is not established, NO is obtained in step ST25, and the process proceeds to step ST26. In step ST26, when the previous sample value (A10 value in this case) is larger than the first predetermined amount by C or more, the process proceeds to step ST27. Here, the same AD value is used when step ST25 → step ST26. The same applies to step ST32 → step ST33. Since the condition A11 does not satisfy this condition, the process advances to step ST27 at the point P1 when the AD value becomes the value P1. Here, the AD value is input to the EXT register. Here P1
Enter the value.

Next, in step ST28, P1
At the point, the counter is incremented by 1 and φ → 1. Step ST
In 29, it is compared whether or not the predetermined count value N has been reached, and if not, the process returns to step ST23 and the next A
Wait for input from the / D converter 220. When the predetermined count is reached, the process proceeds to step ST30 and the track crossing count program is ended. Thus, in the FWD direction, the track crossing count is performed at the points P1, P2 ... P4 as described above.

Next, FIG. 9B shows a waveform when the light beam moves in the REV direction. The waveform advances to steps ST21 to ST23 in the same way as the FWD direction, and since it is the REV direction in step ST23, steps ST31 to ST33. Proceed to. In the case of the REV direction, the track crossing count is performed at points P1 to P4 in FIG. 9B, which are smaller than the maximum value by the first predetermined amount C or more.

Track counting is performed as described above, the carriage driving circuit 406 drives the carriage 403 to position the light beam on the target track TR, and tracking pull-in is performed on the target track, and recording / recording is performed in the same manner as described above. You can enter operations such as playback.

(Fifth Embodiment) FIG. 10 is a waveform diagram of a tracking control signal At signal showing a fifth embodiment of the present invention. If the waveform of the tracking control signal At is a waveform that includes a minute amplitude variation due to electrical noise or the like, there is a possibility that the track crossing count may be erroneously performed. For example, in FIG. 10, the light beam moves in the FWD direction from point A, and according to the flowchart of FIG. 7, point A1 → A2
Since the value becomes smaller at the point and becomes larger at the point A2 → the point A3, the track crossing is counted at the point A3.

Therefore, in the case of the waveform as shown in FIG. 10, the branch of steps ST24 and ST32 of the flowchart of FIG. 7 is changed to the flowchart on the right of FIG. 11A. Similarly, step S
The branch of T25 and step ST31 is shown in FIG. 11 (B), the branch of step ST26 is shown in FIG. 11 (C), step ST33.
The branch of is changed as shown in FIG.

The value of C ₀ shown in the flow chart of FIG. 11 represents the second predetermined amount, and when the value detected and stored in the sample is changed by the second predetermined amount C ₀ or more, a new extreme value is obtained. By doing so, the influence of the minute amplitude fluctuation as described above is removed.

In FIG. 10, at the point A1, a value larger than 0 + C ₀ obtained by adding the second predetermined amount C ₀ to the value 0 at the point A, A1
Since it is a value, the A1 value is adopted and the EXT value is updated. At A2 point, A1 value−C ₀ ≦ A2 value ≦ A1 value + C ₀
Therefore, the sample A is not sampled at the next A3 point and sample E
Update the XT value. Hereinafter, the EXT value is updated at A5, A7, and A8, and is not updated at A9, and “EXT” + C ≦ at P1.
The value of A8 + C> P1 corresponding to AD is established, and the value of the CNT register is updated at the point P1. C at P2 point ...
Update the NT value. As described above, the tracking control signal A
Accurate track counting can be performed even if there is a slight fluctuation in the t waveform.

In the fourth and fifth embodiments, when the moving direction of the optical card is FWD, counting is performed at a position where the value exceeds the minimum value by the first predetermined amount or more, and when REV, the maximum value is changed to the first value. Counting is performed at a position that has become smaller than a predetermined amount, but it does not matter if FWD or REV is counted in either direction.

It is also possible to detect at both positions and count approximately every 1/2 waveform (track).

As described above, according to the present invention in which the level of the tracking control signal At has the level region of n + 1 (n is an integer), for example, = 3 (n = 2), erroneous counting due to noise such as fingerprints is prevented. You can jump and move to the target track accurately and in a short time.

[0099]

As described above, the first aspect of the present invention
According to the invention, since accurate seek operation can be performed even if dirt such as fingerprints adhered on the surface of the card, access time to a desired track can be shortened.

Further, according to the second aspect of the present invention, more accurate seek operation becomes possible by removing the electrical and optical noise of the transverse signal.

Furthermore, according to the third aspect of the present invention, the hardware configuration can be simplified and the device can be downsized.

Further, according to the fourth aspect of the present invention, since the noise of the same phase entering the sensor to be used can be removed, a more accurate seek operation becomes possible.

[Brief description of drawings]

FIG. 1 is a flowchart showing a track counting method according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a track counting device and an ATAF control circuit according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a tracking control signal and a comparator output signal according to the first embodiment of the present invention.

FIG. 4 is a block diagram showing an optical card recording / reproducing apparatus according to the first embodiment of the present invention.

FIG. 5 is a signal waveform diagram showing a second embodiment of the present invention.

FIG. 6 is a signal waveform diagram showing a third embodiment of the present invention.

FIG. 7 is a flowchart showing a track counting method according to a fourth embodiment of the present invention.

FIG. 8 is a block diagram of a track counter and an ATAF control circuit according to a fourth embodiment of the present invention.

FIG. 9 is a diagram showing a tracking control signal and a comparator output signal according to the fourth embodiment of the present invention.

FIG. 10 is a diagram showing a tracking control signal and a comparator output signal according to the fifth embodiment of the present invention.

FIG. 11 is a flowchart showing a track counting method according to a fifth embodiment of the present invention.

FIG. 12 is a diagram showing an optical system of a general optical card recording / reproducing apparatus.

FIG. 13 is a diagram showing a recording surface of an optical card and a light spot for scanning the recording surface and the optical card.

FIG. 14 is a diagram showing a pit recorded on an optical card and a light spot scanning the pit.

FIG. 15 is a diagram showing in detail a photodetector and a signal processing circuit.

FIG. 16 is a diagram showing a conventional tracking signal and its binarized output signal.

FIG. 17 is a diagram showing a conventional tracking signal and a binarized output signal having its hysteresis.

[Explanation of symbols]

 101 semiconductor laser 106 objective lens 107 optical card 109 photodetector 213 comparator 214 comparator 217 MPU 301 movable head 304 fixed head 403 carriage 405 AT / AF control circuit 406 carriage drive circuit 407 track counter 408 signal processing circuit

Claims (9)

[Claims] 1. A record carrier having a plurality of tracks, a light beam generating means for generating a light beam, a moving means for relatively moving the record carrier or the light beam generating means in a direction perpendicular to the track direction, In a track counting device provided with a signal generating means for generating a signal according to the amount of reflected light obtained by irradiating the record carrier with a light beam obtained from a light beam generating means, the signal when moving by the moving means The output of the generating means is binarized by n (n is a positive integer, n ≧ 2) binarizing means having different binarizing levels, and the n
2. A track counting device comprising: a judging means for judging a transition direction of n + 1 level areas divided by the binarizing means; and a counting means for counting when the transition direction changes. 2. The track counting device according to claim 1, wherein the binarizing means has a hysteresis. 3. The track counting device according to claim 1, wherein the binarizing unit is an A / D converter and a digital value comparing unit. 4. The track counting device according to claim 1, wherein the light flux is two light fluxes having a phase shift, and a difference signal between them is binarized. 5. A record carrier having a plurality of tracks, a light beam generating means for generating a light beam, a moving means for relatively moving the record carrier or the light beam generating means in a direction perpendicular to the track direction, In a track counting device equipped with a signal generation means for generating a track crossing signal according to the amount of reflected light obtained by irradiating the record carrier with a light flux obtained from a light flux generation means, the output signal of the signal generation means is A track counting device characterized in that a sample is detected by an A / D converter, a peak is detected based on the detected value, and a track crossing count is performed at a detection point at which a first predetermined amount changes from the peak value. 6. A sample is detected before the output signal of the signal generating means is detected, and peak detection is performed based on a value that has changed from a stored value by a second predetermined amount or more. 6. The track counting device according to claim 5, wherein the cross-track counting is performed at a detection point that has changed by a predetermined amount. 7. The track counting device according to claim 5, wherein the light flux uses two light fluxes having a phase shift, and a track crossing count is performed using a difference signal between the two light fluxes. 8. A record carrier having a plurality of tracks, and a light beam generation means for generating a light beam and irradiating the record carrier.
Moving means for relatively moving the record carrier or the light flux generating means in a direction perpendicular to the track direction, and a light flux obtained from the light flux generating means for irradiating the record carrier and reflecting the reflected light quantity. A binarization device for binarizing the output of the signal generating means by n different (n is a positive integer, n ≧ 2) comparison values Means and
A track counting device comprising: a determination unit that determines a transition direction of n + 1 level areas divided by the n comparison values; and a counting unit that counts when the transition direction changes. 9. The track counting device according to claim 8, further comprising an A / D conversion unit for A / D converting the output of the signal generation unit, and the displacement of each sampling of the A / D conversion unit is a peak. A track counting device, wherein the counting is performed at the next sampling when the value changes by a predetermined amount.