JPH10302378A - Information recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To converge a deceleration starting position in the optimal value in correspondence to the environmental change, to eliminate the overrun and moreover to reduce a low speed driving section to improve the throughput by successively correcting the setting of the deceleration starting position every time of scanning in accordance with the speed wherein a movable head approached the inversion position rushed into a low speed driving starting position. SOLUTION: When the movable head 1 under scanning in the direction L passes through the set deceleration starting position, constant speed control is suspended and a decelerating coil driving voltage is applied to a linear motor 13 with a main controller 7. When the movable head 1 is decelerated, the low speed driving is started so as to maintain that speed and run at the low speed in the direction L and the movable head is stopped at the position of an inversion position sensor 4. The speed in the case of the movable head 1 rushing is detected and outputted with the inversion position sensor 4, when the rushing speed is faster than the reference low speed driving speed, the deceleration starting position is set and changed into the position starting deceleration earlier by a given correcting distance with the main controller 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording / reproducing apparatus, and more particularly to an information recording / reproducing apparatus having a scanning deceleration control means.

[0002]

2. Description of the Related Art Conventionally, there are a magnetic system and an optical system as an information recording / reproducing apparatus for recording and reproducing information on a recording medium. Among them, an optical system apparatus has recently attracted attention. Such optical memories for recording / reproducing information optically include CDs, optical disks, magneto-optical disks, card-shaped recording media (hereinafter, referred to as optical cards), and optical tapes. These optical memories are properly used depending on the purpose. Among them, optical cards have advantages such as good portability, and demand for them is expected in the future.

When such an optical card is used as a recording medium, the optical head and the optical card are moved back and forth relatively in the track direction, so that a light beam from the optical head is scanned on an information track to record information. And playback is performed. In addition, a method is employed in which the optical head and the optical card are relatively moved in the cross-track direction so that the light beam of the optical head accesses a desired track.

FIG. 9 is a schematic plan view showing an example of such an optical card. In the figure, a plurality of tracking tracks T1, T
2, T3,... Are arranged in parallel at equal intervals. Information tracks for recording information are D1, D2, D3, and D3 between the tracking tracks.
... and so on. On both ends of each information track, track numbers for identifying the information tracks are preformatted as N1, N2, N3,... When recording / reproducing information, the track numbers are read and the light beam is read. The current location of is known. 1
When information is recorded on the information track of the book, the number of sectors and the sector size are set arbitrarily, and the writing position of each sector is determined according to each sector type.

FIG. 5 is a block diagram showing an example of an information recording / reproducing apparatus using an optical card. In FIG. 5, reference numeral 1 denotes a movable head for irradiating the optical card C with a light beam, and is configured to reciprocate in a track direction by a driving mechanism (not shown). Reference numeral 23 denotes a fixed head, and the movable head 1 and the fixed head constitute an optical head. Fixed head 2
3, a semiconductor laser 31 and a collimator lens 3
2, a diffraction grating 33, a polarization beam splitter 34, a condenser lens 35, and a photodetector 36 are built therein. Photodetector 3
Reference numeral 6 denotes an optical sensor for receiving the reflected light from the optical card C, which comprises a plurality of light receiving elements.

In the movable head 1, a reflecting prism 37,
An objective lens 39, a focus actuator 38, and a tracking actuator 40 are provided. The laser beam of the semiconductor laser 31 passes through the polarization beam splitter 34, is narrowed down by the objective lens 39, and is condensed as a minute light spot on the information track of the optical card C.

The main controller 7 is a control circuit for controlling each section, controls the card tray drive circuit 53, and moves the card tray 24 in the cross-track direction. The optical card C is placed on the card tray 24, and the card tray 24 is moved in the cross-track direction by the drive signal of the card tray drive circuit 53, so that the light beam of the movable head 1 accesses a desired track.

The main controller 7 controls the movable head drive circuit 54 to reciprocate the movable head 1 in the track direction. The movable head drive circuit 54 will be described later in detail, but the linear motor 13 shown in FIG. 6 is controlled based on the control of the main controller 7, and the movable head 1 is reciprocally driven in the track direction, so that the light beam Scans over the information track.

When information is recorded on the optical card, the main controller 7 simultaneously transmits a recording signal to the modulation circuit 50 and modulates it by a predetermined modulation method while scanning the information track with the light beam. Then, by driving the semiconductor laser 31 according to the modulation signal, the intensity-modulated light beam scans on the information track, and a series of information is recorded. The light receiving processing circuit 41 processes the light receiving signal of each sensor element of the photodetector 36 during this scanning, detects a focus error signal and a tracking error signal, and performs focus control in a focus control loop and a tracking control loop based on the signals. Tracking control is performed.

That is, the differential amplifier 42, the phase compensator 43,
The driver 45 forms a part of a focus control loop, drives the focus actuator 38 based on the focus error signal, and displaces the objective lens 39 in the focus direction, so that the light beam focuses on the medium surface. Control is performed.

Also, a differential amplifier 46, a phase compensator 47,
The driver 49 forms a part of a tracking control loop, and the tracking actuator 40 is driven based on the tracking error signal, and the objective lens 39 is displaced in the tracking direction so that the light beam does not deviate from the information track. Is performed.

On the other hand, when reproducing information, a light beam is scanned on a target information track, and at this time, a light receiving processing circuit 41 processes a light receiving signal of the photodetector 36 to generate an information reproducing signal. The information reproduction signal is demodulated by the demodulation circuit 51 and sent to the main controller 7. In FIG. 5, 2
6 is a CD for detecting recorded information on an information track.
(Carrier Detect) detection circuit, which outputs a CD signal when recording information is detected. Reference numeral 52 denotes an A / D converter for taking the focus error signal and the tracking error signal into the main controller 7.

Hereinafter, the movable head driving circuit will be described in detail.

FIG. 10 is a block diagram showing an example of the movable head drive circuit 54. In FIG. 10, reference numeral 1 denotes the movable head shown in FIG.
4. The position encoder 2 is attached. The position encoder 2 is for detecting the speed and the moving distance of the movable head 1, and a slit plate 15 having slits formed at regular intervals is provided on a side portion thereof. The slit plate 15 is provided along the scanning direction of the movable head 1, and a signal is output from the position encoder 2 every time the movable head 1 moves a predetermined distance. Further, the cycle of this signal changes according to the speed, and the speed and the moving distance of the movable head 1 are detected using this. Reference numeral 16 denotes a waveform shaping circuit for shaping the signal of the position encoder 2 into a rectangular wave to generate a moving signal, and 104 denotes a reference signal of a constant frequency output from the reference frequency generating circuit 105 and a waveform shaping circuit 16.
An FV converter 106 for generating a frequency error signal from the output signal of the FV converter 104 is a lock detection circuit for detecting that the speed of the linear motor has reached a predetermined speed based on the output of the FV converter 104. 7 is a main controller shown in FIG. 5, 108 is a phase compensator, 109 is a drive voltage for moving the movable head 1 to a target reversal position sensor at a low speed after the movable head 1 has decelerated to a predetermined speed. Is an acceleration / deceleration drive voltage generation circuit for generating acceleration and deceleration voltages for the linear motor.

Reference numeral 111 denotes a phase compensator 108, an acceleration / deceleration drive voltage generation circuit 110,
A switch for selectively switching signals from the low-speed drive voltage generation circuit 109 and a phase compensator 122 described later.

Reference numeral 112 denotes a polarity switching circuit for switching the polarity of the coil driving voltage in accordance with the direction of movement of the movable head 1 in accordance with an instruction from the main controller 7. Reference numeral 12 denotes a driving voltage for the linear motor coil 13. This is a driver for power amplification. Reference numerals 3 and 4 denote reversal position sensors for detecting that the movable head 1 has reached the reversal position.
That is, the light shielding plate 14 is attached to the movable head 1 as described above, and when the movable head 1 moves in the L direction or the R direction and the end of the light shielding plate 14 moves to the inversion position sensor 3 or 4. The movable head 1 reaches the scanning end by the reversing position sensor 3 or 4.
The movable head 1 when not performing scanning is controlled to stop at this reversal position by a position control circuit described later.

Reference numeral 5 denotes an inversion position sensor selection switch for selecting either the signal of the inversion position sensor 3 or 4 in accordance with an instruction from the main controller 7, and 119 denotes an inversion selected by the inversion position sensor selection switch 5. This is a comparator circuit for comparing the output signal of the position sensor 3 or 4 at a constant level and sending the output signal of the comparator circuit to the main controller 7. The output signal of the comparator circuit 119 serves as a start signal for controlling the position of the movable head 1 as described later. Reference numeral 120 denotes a differential for generating a position error signal by comparing the output signal of the inversion position sensor selected by the inversion position sensor selection switch 5 with a constant voltage corresponding to the target position output from the constant voltage generation circuit 121. The amplifier 122 is a phase compensator for phase-compensating the position error signal. These inversion position sensors 3 or 4, the constant voltage generation circuit 121, the differential amplifier 12
0, a phase control loop closed by the phase compensator 122 and the linear motor is formed.

Next, the operation of the movable head drive circuit 54 will be described with reference to FIG. First, at a point A in the initial state, main controller 7 sends a switch switching signal (FIG. 11C) to switch 111, and connects switch 111 to the side (b). At this time, the polarity switching circuit 112 is switched to a configuration in which the carriage 1 is to be sent in the L direction according to an instruction from the main control device 7, and the polarity of the driving voltage of the driver 12 is also switched to the polarity corresponding to the L direction. In this state, an acceleration / deceleration signal (FIG. 11D) is sent from the main controller 7 to the acceleration / deceleration drive voltage generation circuit 110, and the acceleration drive voltage (FIG. 11 (b) are applied to the linear motor coil 13. The movable head 1 is accelerated by this driving as shown in FIG. 11A and is sent in the L direction.

By the way, as shown in FIG. 11, the voltage of the output signal of the inversion position sensors 3 and 4 is Vcc / 2 at the inversion position, rises as the distance from the inversion position increases, and the light shielding plate 14 is moved from the inversion position sensor. Since it becomes Vcc at the place where it exits, for example, the comparator circuit 119
Is set to 80% of Vcc to obtain FIG.
An output signal of the comparator circuit as shown in (h) is obtained.

Here, the main controller 7 inputs a comparator circuit output signal, which is a result of comparison of the output voltage of the inversion position sensor 3 with the reference voltage, from the comparator circuit 119,
Monitoring. At point A in the initial state of the inversion position, the inversion position sensor selection switch 5 is connected to the (e) side, and the output signal of the inversion position sensor 3 is output to the comparator circuit 119. The main controller 7 monitors the output signal of the comparator circuit as described above, and resets the position counter when the output signal of the comparator circuit is inverted from the low level to the high level as shown in FIG. 1
At 6, the counting of the encoder signal whose waveform has been shaped into a rectangular wave is started. This count value (hereinafter, referred to as an encoder count value) is a moving distance of the movable head 1 based on the position of the reversing position sensor 3. The counting of the encoder count value is performed by an interrupt process of the main controller 7.

On the other hand, the FV converter 104 generates a frequency error signal from the encoder signal converted into a rectangular wave by the waveform shaping circuit 16 and the reference frequency signal of the reference frequency generation circuit 105, and outputs this to the lock detection circuit 106. I do. When the voltage of the frequency error signal reaches a predetermined level, the lock detection circuit 106 detects that the moving speed of the movable head 1 has reached the predetermined speed, and outputs a lock detection signal (FIG. 11E) to the main controller 7. I do. At point B where the lock detection signal is generated, main controller 7 controls the acceleration / deceleration signal (FIG. 11).
(D)) is set to the low level, and the switch 111 is switched to the (a) side. As a result, the control mode is switched from the acceleration mode to the speed control mode, the linear motor coil 13 is driven based on the frequency error signal phase-compensated by the phase compensator 108, and the movable head 1 Sent in the direction.

The main controller 7 connects the inversion position sensor selection switch 5 to the (f) side at the point B (FIG. 11).
(J)). That is, since the movable head 1 is now moving in the L direction, the reversing position sensor 4 at the reversing position corresponding to this is selected. During speed control,
A light beam from the movable head 1 scans the optical card C placed on the card tray 24 at a constant speed. During this speed control period, an information signal is recorded on an information track or information from the information track is recorded. The signal is reproduced.

After recording or reproduction of information is completed, main controller 7 starts processing as shown in the flowchart of FIG. 12, and the encoder count value reaches point C at which the encoder count value reaches a predetermined count value X (FIG. 11). ) Wait.

In FIG. 12, at step S801, an encoder count value X for starting deceleration is calculated. X is
It is calculated by the following equation.

The value of the quotient X where X = (target deceleration start position / encoder pitch) corresponds to the number of encoder signal counts from the inversion position sensor position to the deceleration start target position.

Next, the main controller 7 waits until the encoder count becomes equal to or larger than the value of X by the loop of the branch S802. Then, the point where the encoder count number becomes equal to or more than the value of X and the loop of branch S802 escapes with YES is point C (FIG. 11), that is, the position moved by a predetermined moving distance measured at the encoder pitch from the inversion position. . At this point, main controller 7 connects switch 111 again to the (b) side, sets the polarity switching signal (FIG. 11 (f)) to low level, and sets acceleration / deceleration drive voltage generation circuit 110
By outputting the deceleration voltage from the motor, the deceleration drive voltage is applied to the linear motor coil 13 (sections C to D in FIG. 11B).
Is applied. As a result, the movable head 1 is braked as shown in the section C to D in FIG. At the time D when the speed of the movable head 1 has decreased to the predetermined speed m, the main controller 7 connects the switch 111 to the (c) side, sets the polarity switching signal (FIG. 11 (f)) to a high level, and further sets the L direction. Set to move to. At the same time, a low-speed drive signal is output from the low-speed drive voltage generation circuit 109 (sections D to E in FIG. 11I), and a drive voltage for driving the movable head 1 to the linear motor coil 13 at low speed (see FIG. b) section from D to E). As a result, the movable head 1 continues to move at a low speed of m in the L direction. During this movement, the output voltage of the inversion position sensor 4 is sent to the comparator circuit 119. When the output voltage of the inversion position sensor 4 reaches a predetermined voltage or lower, the comparator circuit 119 switches the high-level comparator circuit output signal (FIG. 11H) to a low level. The main controller 7 switches the switch 111 at this position E.
To the (d) side, and as a result, a position control loop is formed.

On the other hand, in the differential amplifier 120, the output signal of the inversion position sensor 4 is compared with a constant voltage of the constant voltage generation circuit 121 to generate a position error signal. This position error signal is phase-compensated by the phase compensator 122, output to the driver 12 via the switch 111, and applied to the linear motor coil 13. Thus, the position control loop operates, and the movable head 1 automatically stops at the target position in the L direction. This completes the movement of the movable head 1 in the L direction.

Note that the main controller 7 sets the movable head 1 to R
When sending in the direction, the same control is performed.

[0029]

In recent years, however, the amount of information has been enormously increasing, and a large-capacity, high-speed information recording / reproducing apparatus has been desired. To meet such demands, it is necessary to record information at a high density and to increase the scanning speed. In particular, in an optical card recording / reproducing apparatus that performs scanning by linear reciprocating drive, in order to increase the scanning speed, more precise control is required for acceleration and deceleration control of the movable head.

That is, after the motor completes acceleration within a limited short section (section from the reversing position to the track number start position) by the acceleration control, the motor is stabilized at a constant speed by the speed control, and the motor is decelerated by the deceleration control. After the deceleration is completed within a limited short section (a section from the track number end position to the reversing position), the vehicle must be finally stopped at the reversing position by position control.

Since an area required for acceleration and deceleration must be ensured in order to realize a higher scanning speed, the reversal position is almost at the end of the card.
For this reason, there is a possibility that an overrun of the stop position is caused particularly in the deceleration process. When an overrun occurs, the light spot deviates to the outside of the medium surface, not only losing the current track, but also having to start over from re-focusing, causing a large time loss.

If the deceleration is started early to eliminate the overline, the low-speed driving section (sections D to E in FIG. 11) becomes longer, and the throughput of the entire scanning is greatly reduced. I will. Therefore, in order to realize ideal deceleration control with improved throughput, it is necessary to control this low-speed drive section length to be as close to 0 as possible.

That is, if the deceleration start position is too close to the reversal position, a problem of overrun occurs, and if the deceleration start position is too far from the reversal position, a problem of reduction in throughput occurs. Must be specified. However, in the deceleration processing in the conventional example, the deceleration start position is a fixed value, and the deceleration drive is an open drive, so that the frictional resistance state of the support shaft of the movable head 1 and the inclination of the apparatus due to the installation state of the apparatus. However, stable deceleration control could not be realized.

Even if the deceleration process includes speed control using speed detection by an encoder instead of open drive, it is necessary to cause the reversing position sensor to just enter the reversal position sensor when the low speed drive speed m is reached. Needs to provide a means for correcting the deceleration start position.

The present invention has been made in view of the above-mentioned conventional problems, and automatically corrects the deceleration start position to an optimum value by automatically changing the deceleration start position according to the situation, and overruns the stop position. It is an object of the present invention to realize an information recording / reproducing apparatus which can eliminate the low-speed driving section and eliminate it.

[0036]

An information recording / reproducing apparatus according to the present invention comprises reciprocating one of a carriage for mounting an information recording medium and a head for recording and reproducing information on the recording medium. An information recording / reproducing apparatus for scanning a recording / reproducing signal on an information track of the recording medium and recording information or reproducing recorded information.
Reversing position detecting means for outputting a position signal at the reversing position of the carriage or the head; moving distance detecting means for detecting that the carriage or the head has moved a predetermined distance; A head entry speed detecting means for automatically changing and correcting a position at which scanning deceleration is started based on an output value of the entry speed detection means.

The information recording / reproducing apparatus according to the present invention is characterized in that all or a part of the drive control in deceleration of the carriage or the head is an open drive.

Further, in the information recording / reproducing apparatus according to the present invention, the method for automatically changing and correcting the position at which the scanning is started to decelerate is such that the deceleration is started a predetermined distance earlier when the rush speed is higher than a prescribed speed. When the inrush speed is lower than a prescribed speed, a change is made such that deceleration is started with a delay of a certain distance.

Further, in the information recording / reproducing apparatus according to the present invention, the method of automatically changing and correcting the position at which the scanning is started to decelerate is characterized in that a distance obtained by substituting the inrush speed into a correction distance calculation function is used as a correction amount. It is characterized by the following.

Further, in the information recording / reproducing apparatus according to the present invention, the method of automatically changing and correcting the position at which the scanning is started to decelerate may include a step of setting a dead zone where no correction is made when the inrush speed is near a prescribed speed. When the inrush speed is higher than a specified speed, the distance obtained by substituting the inrush speed into the correction distance calculation function is used as a correction amount.On the other hand, when the inrush speed is lower than a specified speed, a fixed distance delay occurs. It is characterized in that a change is made to start deceleration.

Further, in the information recording / reproducing apparatus according to the present invention, the inversion position detecting means includes at least one set of photointerrupters including a light emitting diode and a phototransistor, and a light shielding plate fixed to the carriage or the head includes: The photo-interrupter outputs a position signal at a reversal position of a scanning end by being configured to pass between the light-emitting diode and the photo-transistor of the photo-interrupter.

Further, the information recording / reproducing apparatus according to the present invention further comprises: the information recording / reproducing apparatus according to the present invention, wherein the moving distance detecting means counts an output signal of an encoder provided on the carriage or the head. The moving distance of the carriage or the head is detected.

Further, the information recording / reproducing apparatus according to the present invention is characterized in that the value of the position at which the deceleration of the scanning is started is managed independently for the forward direction and the reverse direction of the scanning.

Further, the information recording / reproducing apparatus according to the present invention sets the initial value of the position at which the scanning deceleration is started to EEP.
It is stored in a non-volatile memory such as a ROM.

[0045]

FIG. 5 is a block diagram showing a movable head drive circuit of an optical information recording / reproducing apparatus according to this embodiment. FIG. 6 shows a specific configuration example of the movable head driving circuit 54 therein. In this embodiment, the optical card described with reference to FIG. 9 is used as a recording medium.

FIG. 6 is a block diagram showing an example of the movable head drive circuit 54. In FIG. 6, reference numeral 1 denotes a movable head shown in FIG. 5, on which a light shielding plate 14 and an encoder 2 are mounted.

The encoder 2 detects a moving speed and a moving distance of the movable head 1, and a slit plate 15 having slits formed at regular intervals is provided on a side portion thereof. The slit plate 15 is provided along the scanning direction of the movable head 1, and a signal is output from the encoder 2 every time the movable head 1 moves a predetermined distance.

Next, reference numeral 7 denotes a main controller shown in FIG. Reference numeral 16 denotes a waveform shaping circuit for shaping the output signal of the encoder 2 into a rectangular wave, and the waveform-shaped signal is input to the main controller 7 as an interrupt signal (hereinafter, referred to as an encoder interrupt signal). The moving distance of the movable head 1 can be detected by counting this signal. The period of this signal changes according to the moving speed, and the moving speed of the movable head 1 is detected by measuring the period with the timer 8. The timer 8 is a digital timer that counts with a clock (not shown), and the frequency of the clock is set to be much higher than the frequency corresponding to the encoder interrupt period generated while the movable head 1 is moving at high speed.

On the other hand, a driving circuit for the linear motor 13 will be described with reference to FIG. 6. A control signal for controlling the linear motor 13 is converted into an analog voltage by the D / A converter 10, The driving voltage of the motor 13 is sent to the driver 12 for power amplification. The D / A converter 10 has an output value of 0-5V, and the voltage corresponding to 0V of the output of the drive circuit is set to its central value of 2.5V. Thereby, the driving force is L (left) or R depending on whether the output value to the D / A converter 10 is high or low based on the center value of 2.5 V.
The driving direction to the (right) direction can be controlled at the same time.

In FIG. 6, reference numerals 3 and 4 denote reversal position sensors for detecting that the movable head 1 has reached the reversal position. That is, the movable head 1 has the light shielding plate 1 as described above.
When the movable head 1 moves in the L direction or the R direction and the end of the light shielding plate 14 moves to the position 3 or 4 of the reversing position sensor, the movable head 1 is output by the reversing position sensor 3 or 4. It is detected that 1 has reached the scanning end. When scanning is not being performed, the movable head 1 is controlled to stop at this reversal position by position control described later.

Since the output signals of the inversion position sensors 3 and 4 do not need to be read at the same time, an inversion position sensor selection switch 5 is provided for selecting either one of them. The signal of either the reversing position sensor 3 or 4 selected by the instruction of the main controller 7 is converted into a digital signal by the A / D converter 6 and read into the main controller 7.

In the present embodiment, the reversing position sensors 3 and 4 also function as sensors for detecting the rush speed of the movable head 1, and will be described in more detail.

FIG. 4 is a diagram showing a specific configuration of the inversion position sensors 3 and 4 and a change in the output signal of the inversion position sensor when the light shielding plate 14 passes. As shown in FIG. 4A, the reversing position sensors 3 and 4 are formed of a photo interrupter in which a light emitting diode D and a photo transistor Q are combined. The light shielding plate 14 is configured to move between the light emitting diodes D of the reversing position sensors 3 and 4 and the phototransistor Q in the L direction and the R direction. The reversing position sensor selection switch selects the reversing position sensor 3 or 4. For example, in the deceleration control when scanning is performed in the L direction, the reversing position sensor selection switch 5 selects the reversing position sensor 4.

FIG. 4B shows an output signal V of the inversion position sensor 4 when the light shielding plate 14 passes between the inversion position sensors 4.
x is shown. The voltage of the output signal Vx is substantially equal to the power supply voltage Vcc in a completely transmissive state without the light shielding plate 14. From this state, the transmitted light gradually changes from the position where the light-shielding plate 14 moves in the L direction, and the end of the light-shielding plate 14 approaches the inside of the sensor. When it reaches, the photocurrent of the phototransistor Q becomes half of that of the inversion position sensor 4 at the time of complete light transmission, and the voltage of the output signal Vx becomes almost half of the power supply voltage Vcc. Further, when the light-shielding plate 14 continues to move in the L direction and the inversion position sensor 4 is completely shielded from light by the light-shielding plate 14, the phototransistor Q is turned off, and the voltage of the output signal Vx is almost 0V. Become.

As described above, since the position information of the light shielding plate 14 is obtained from the output voltage of the inversion position sensor, the distance can be obtained by multiplying the voltage of the output signal Vx by the voltage-to-distance conversion coefficient. Further, the moving speed can be detected by obtaining the moving distance per unit time.

The voltage of the output signal Vx is equal to the power supply voltage Vcc.
Is adjusted so that the movable head 1 is the target stop position in the L direction. In the position control loop, the scanning is completed, the movable head approaches the inversion position sensor 4, and the output voltage of the inversion position sensor 4 is, for example, 8 Vcc.
It starts to work from the point where it becomes 0%, and works to stop the movable head 1 at the target stop position.

By setting the inversion position sensor stop target position to a position outside of the scanning area of the movable head 1, the inversion position sensors 3 and 4 allow the movable head 1 to move.
Since the area where the speed can be detected can be widened, such a setting may be made.

In the deceleration control and the stop position control when the light shielding plate 14 moves in the R direction, the inversion position sensor selection switch 5 is set so that the inversion position sensor 3 is selected, so that the movement and the stop in the L direction are performed. The same output signal can be obtained.

Next, the operation of the movable head driving circuit 54 in scanning in this embodiment will be described with reference to FIG. FIG. 3 is a time chart for explaining the scanning operation in the present embodiment.

First, at the point A in the initial state, the main controller 7 controls the movable head 1 to stop at the reverse position by the position control servo as a process for the movable head 1 when scanning is not performed. Have been. Main controller 7 is A
At this point, the inversion position sensor selection switch 5 is switched to the inversion position sensor 3 side. Then, the A / D converter 6 is periodically read, and the position error amount between the inversion position sensor stop target position and the current position of the movable head 1 is calculated.
A control loop is configured to multiply the gain and output a corresponding speed signal to the D / A converter 10 so that the position servo is performed.

From this state, when starting the scanning acceleration,
The main controller 7 first cuts the position control loop and sets the voltage close to the maximum voltage to D / A in order to move the movable head 1 in the L direction.
Output to converter 10. As a result, the acceleration coil drive voltage (FIG. 3B) amplified by the driver 12 is applied to the linear motor 13, and the movable head 1 is accelerated by this open drive force as shown in FIG. Sent in the direction.

While the movable head 1 is accelerating, the main controller 7 first monitors the state of the reversing position sensor 3 based on the input from the A / D converter 6, and monitors the state over a predetermined voltage (FIG. 3).
(D) The point B which reaches the point is detected. The point B indicates the position where the reversing position sensor 3 has escaped, and the encoder starts counting from the position of the point B. The encoder count is thereafter incremented each time an interrupt occurs.
This count is hereinafter referred to as an encoder counter. The encoder counter serves as position information of the movable head 1 with reference to the point B.

Thereafter, the main controller 7 can determine and detect the average moving speed of the movable head 1 by measuring the period of the encoder interrupt signal using the timer 8. In this way, main controller 7 monitors point C at which 90% of scanning target speed value k is reached.

The main controller 7 that has detected the point C forms a constant speed control loop from here, and switches the control so that the movable head 1 scans at a constant speed. At this time, the main controller 7 periodically multiplies the gain by the speed error amount between the average moving speed of the movable head 1 obtained by measuring the period of the encoder interrupt signal and the target speed k, and calculates the multiplication result by D Output to the A / A converter 10 to form a control loop, thereby performing constant speed servo. In addition, main controller 7
Switches the contact point of the inversion position sensor selection switch 5 at point C so as to select the inversion position sensor 4 (FIG. 3).
(E)). This is because when the point C is detected, the movable head 1
Is for selecting the reversal position sensor 4 on the left side for detecting the next stop position, since it is moving in the L direction.

After the control mode is switched from the acceleration mode to the speed control mode, the movable head 1 eventually reaches a point D at which the speed becomes the scanning target speed value k. In the speed control mode, a light beam from the movable head 1 scans the optical card C placed on the card tray 24 at a constant speed. Playback is performed. Here, the details are omitted.

Next, when the recording / reproduction is completed, the main controller starts detecting the deceleration start position.

The optimum value LO of the deceleration start position is EEPROM
Are recorded and set in the nonvolatile memory 9. However, the optimal value L of the deceleration start position in each of the L direction and the R direction
O is independently recorded and stored. Each of these,
L direction deceleration start position LL and R direction deceleration start position L
By reading in advance from the EEPROM as R and reading it into the work memory in the main controller 7, the value of the deceleration start position can be used as a variable. Hereinafter, a second method of detecting the deceleration start position performed after the recording or reproduction of information is completed in the present embodiment will be described. Note that the first method of detecting the deceleration start position has been described with reference to FIG.

After recording or reproduction of information is completed, main controller 7 detects a deceleration start position in order to stop movable head 1. The deceleration start position is measured as a value of the distance from point B at the start of scanning, and the optimum value L0 is recorded and set in advance in a nonvolatile memory 9 such as an EEPROM in an adjustment process at the time of shipment of the apparatus. As a means for detecting the deceleration start position more accurately than the pitch of the encoder, a method described below is employed.

FIG. 8 is a flowchart showing a method of detecting the deceleration start position. In FIG. 8, error processing is omitted for easy understanding of the processing procedure.

The main controller 7 performs a process for waiting until the deceleration start target position is reached based on the deceleration start target position L0 based on the reversal position B read from the nonvolatile memory 9. In FIG. 8, when waiting for the target position starts, the main control device 7
The quotient obtained by dividing the distance L0 to the deceleration start target position read by the encoder pitch by the encoder pitch is stored as Y (processing S
201).

The quotient of Y = (target position / encoder pitch) That is, the value of Y corresponds to the number of encoder interrupt signal counts up to the target position. Next, the main controller 7
Is the remainder of dividing target position L0 by encoder pitch
(Step S202).

A = Remainder of (Target Position / Encoder Pitch) That is, the value of A corresponds to an indivisible remainder distance when the distance to the target position is divided by the encoder pitch.

Subsequently, the flow branches depending on whether or not the encoder counter value has reached Y in branch S203. In the branch S203, “encoder count = Y” is true (YE
When the process branches to S), that is, when it reaches the encoder section in which the deceleration start is executed, a process S20 described later is performed.
4 and the subsequent branch S205, the distance interpolation between the encoder interrupts is performed to detect the deceleration start position.
First, in step S204, the target value Z of the timer counter up to the deceleration start target position is calculated. Z is obtained by the following equation.

Z = (capture counter ÷ encoder pitch) × A The capture counter referred to here is a timer counter value obtained by measuring the immediately preceding encoder interrupt section by the timer 8.

That is, the value of Z is a timer counter value of the timer 8 corresponding to the indivisible remainder A when the distance to the target position obtained in the processing S202 is divided by the encoder pitch.

Here, a description will be given of obtaining the target value Z of the timer counter using the capture counter. The capture counter corresponds to the measured value of the passage time of the encoder interval immediately before the deceleration start target position. This is a value including the speed deviation near the deceleration start target position. For example, when the scanning speed is higher than the design value, the capture counter is small (for a short time), while when the scanning speed is lower than the design value, the capture counter is large (for the short time). For a long time). When the calculation is performed using the value including the speed deviation and the target value Z of the timer counter is obtained, the speed deviation can be absorbed and more accurate position information can be interpolated.

Next, the main controller 7 determines whether or not the timer counter value of the timer 6 is equal to or greater than Z in a branch S205. If the timer counter value has not reached Z, the flow returns to the processing S203 again to perform the same processing. Then, the processing of S203 to S205 is repeated, and the processing is terminated when the timer counter value becomes equal to or greater than Z.

On the other hand, when branching to NO in branch S203, main controller 7 subsequently determines whether or not the encoder counter value exceeds the value of Y (branch S2).
06). If NO in branch S206, that is, if it can be determined that the target position has not yet reached the deceleration start target position, step S203 is repeated.
And the same processing is performed. On the other hand, if YES is determined in S206, this is because the next encoder interrupt signal has already occurred before the timer counter reaches the target value due to factors such as variations in encoder accuracy and speed deviation of the movable head 1. Indicates that an interrupt has been detected. Accordingly, if the determination in step S206 is YES, and the next encoder interrupt signal interrupt occurs before the timer counter target value is reached, it can be determined that the vehicle has passed the deceleration start target position. finish.

Thus, the waiting for the deceleration start target position is completed, and it can be determined that the set deceleration start target position has been reached at this end point.

Main control device 7 detecting deceleration start position E
Reduces the almost maximum voltage to D / in order to stop the speed control and accelerate the movable head 1 in the R direction (decelerate in the L direction).
Output to the A converter 10. That is, the deceleration coil drive voltage (FIG. 3)
(B)) is applied to the linear motor 13 and the movable head 1
As shown in FIG. 3A, the brake is applied by this open driving force to decelerate.

Main controller 7 detects point F where the speed of movable head 1 has been reduced to a predetermined speed m during deceleration. The predetermined speed m at this time is a rush speed specified for performing a stable stop in performing the later stop control, and this speed is hereinafter referred to as a low drive speed m. When the point F is detected, a voltage enough to maintain the low drive speed m is applied in the L direction, and the movable head 1 is sent to the reversing position sensor 4. As a result, the movable head 1 continues to move at a low speed in the L direction, and it can be confirmed by the signal of the A / D converter 6 that the light shielding plate 14 has been shielded from light by the inversion position sensor 4.

Then, at point G, main controller 7
As processing for the movable head 1 when scanning is not being performed, a position control loop is configured to perform control so as to stop at the position of the reversal position sensor 4. Thus, the position control loop operates, and the movable head 1 automatically stops at the target position in the L direction. This completes the movement of the movable head 1 in the L direction.

The main controller 7 performs the same control when moving the movable head 1 in the R direction.

The operation after the detection of the deceleration position will be described below. The main controller 7 that has detected the deceleration start position E breaks the speed control loop, and D / A converts a voltage almost close to the maximum voltage in order to accelerate the movable head 1 in the R direction (decelerate in the L direction). Output to the container 10. In other words, the deceleration drive voltage (FIG. 3B) amplified by the driver 12 is applied to the linear motor 13, whereby the movable head 1 is braked by the open driving force as shown in FIG. 3A. Slowing down.

The deceleration position correction control procedure is shown in the flowchart of FIG. The details will be described below with reference to the drawings.
During deceleration, main controller 7 reads the signal of the inversion position sensor via A / D converter 6 in branch S101, and monitors point F in FIG. 3 where inversion position sensor 4 detects light-shielding plate 14. (FIG. 3D). For example, this is the output signal V
This is performed by monitoring whether the voltage of x becomes 80% or less of the power supply voltage Vcc.

If the entry of the light-shielding plate cannot be detected in the branch S101, the main controller 7 measures the period of the encoder interrupt signal by using the timer 8 in the branch S102, so that the speed of the movable head 1 of the encoder becomes predetermined. It monitors whether the speed has been reduced to the speed n. This predetermined speed n is a speed smaller than the low-speed driving speed m described in the conventional example, and an error process for preventing a phenomenon that the movable head 1 moves in the reverse direction (R direction) when the deceleration process is continued further. (See FIG. 3A).

When an event that matches the branch condition cannot be detected in the branch S101 and the branch S102, the main controller 7 repeats the branch S101 and the branch S102, and repeats until either the branch S101 or the branch 102 can be detected.

When the processing is branched at the branch S101, the branch S101 is performed.
The process exits from the loop of S102 when the movable head 1 reaches the reversing position sensor 4 before the scanning speed of the movable head 1 becomes equal to or lower than the speed n, and the process branches to S10.
In step 2, the process exits from the loop of branches S101 and S102 when the scanning speed of the movable head 1 becomes lower than the speed n before reaching the reversal position sensor 4.

The main controller 7 having detected either the condition of the branch S101 or the condition of the branch 102 applies a voltage sufficient to maintain the current speed in the L direction in the processing S103, and moves the movable head 1 to the reversing position sensor 4. Gives driving force to feed.

Next, in the processing S104, the main controller 7
The output signal Vx of the inversion position sensor 4 is read from the / D converter 6, and the position information X1 of the light shielding plate 14 shown in the following equation is calculated.

X1 = Vx × distance conversion coefficient After waiting for a predetermined time t milliseconds for speed detection, the output signal V of the inversion position sensor 4 is again output from the A / D converter 6.
x, the position information X of the light shielding plate 14 after a predetermined time t
2 is calculated by the following equation.

X2 = Vx × distance conversion coefficient From the above X1 and X2, the rush speed v of the light shielding plate 14 to the reversing position sensor 4 can be calculated by the following equation.

V = (X2−X1) / t In step S105, a correction distance is obtained based on the rush speed v of the light shielding plate 14 obtained in step S104, and the deceleration start position LL in the next scanning in the L direction is performed. Is updated to correct the deceleration start position. The correction method will be described later. By this correction, the intrusion speed v at which the light shielding plate 14 enters the reversing position sensor automatically converges to the low-speed drive target speed m described in the conventional example. In other words, since the detection of the point D and the detection of the point E in FIG. 11 in the conventional example work so as to coincide with each other, it works as a function of automatically eliminating the low-speed driving period. Thereby, the throughput can be improved.

Then, the main controller 7 monitors the point G in FIG. 3 where the light shielding plate 14 reaches the target stop position in the branch S106. This is performed by monitoring whether the voltage of the output signal Vx becomes less than half of the power supply voltage Vcc. Lastly, the main controller 7 configures a position control loop as processing for the movable head 1 when scanning is not performed in step S107,
Control is performed to stop at the position of the reversing position sensor 4. Thus, the position control loop operates, and the movable head 1 automatically stops at the target position in the L direction. With the above, the movable head 1
Is completed in the L direction.

When the movable head 1 is moved in the R direction, the main controller 7 performs the same control by setting the deceleration start position to LR and switching the inversion position sensor selection switch 5 to the inversion position sensor 3 side.

[First Embodiment] The first embodiment of the correction method will be described in detail with reference to the flowchart shown in FIG. In the first embodiment, the entry speed v and the low drive speed m are compared by the branch SA1, and v> m, v =
Branches into three, m and v <m.

If v> m, that is, if the inrush speed v is higher than the low speed driving speed m, the deceleration start position LL is corrected by the processing SA2 so that the deceleration start is performed earlier by a fixed correction distance Ld. That is, if v> m, LL = LL
−Ld.

If v = m, that is, if the inrush speed v is equal to the low drive speed m, no correction is made.

On the other hand, if v <m, that is, if the inrush speed v is lower than the low speed driving speed m, the deceleration start position LL is corrected by the processing SA3 so that the deceleration start is performed later by a certain correction distance Ld. That is, if v> m, LL
= LL + Ld.

In the method of the first embodiment, only one fixed correction distance Ld is corrected for one scan.
The deceleration start position gradually approaches the optimum value. Therefore, there is a feature that there is no fear of excessively correcting an unexpected disturbance.

[Second Embodiment] A second embodiment of the correction method will be described in detail with reference to the flowchart shown in FIG. In the second embodiment, the correction distance is obtained by substituting the entry speed v into a function for calculating the optimum correction distance by branching SB1. For example, the function is as follows.

LL = LL− (v−m) × Correction Distance Coefficient The second embodiment is characterized in that a correction is quickly made for an environmental change.

In the above equation, the term of (vm) × correction distance coefficient is a correction distance calculation function. Further, the correction distance coefficient is expressed by using a speed k at the start of deceleration and an acceleration a at the time of deceleration, where correction distance coefficient = k / a.

[Third Embodiment] A third embodiment of the correction method will be described in detail with reference to the flowchart shown in FIG. In the third embodiment, the low drive speed m
And the correction method of the second embodiment is adopted when the rush speed v is higher than m + α, and when the rush speed is lower than the low drive speed m, the correction method of the first embodiment is used. This is a method that employs a correction method. This is an embodiment in which strict control is performed to prevent overrun.

In the third embodiment, if the inrush speed v is higher than the low drive speed m + α in the branch SC1, the process branches to process SC2, and the inrush speed v is substituted into the function for calculating the optimum correction distance in process SC2. Thus, the correction distance is obtained and the deceleration start position is corrected. That is, v> m + α
Then, LL = LL− (vm) × correction distance coefficient.

In the branch SC1, if v ≦ m + α, the branch S
Move to C3. In the branch SC3, if the rush speed v is lower than the low-speed drive speed m, the process branches to the process SC4, and the process SC4 corrects the LL by starting the deceleration slower by a certain distance Ld. That is, if v <m, LL = L
L + Ld.

When the inrush speed v is equal to or higher than the low-speed driving speed m and equal to or lower than the low-speed driving speed m + α, no correction is performed. That is, m ≦
The range of the inrush speed v that satisfies v ≦ m + α is a dead zone and is not corrected.

If m ≦ v ≦ m + α, no correction is made.

In the third embodiment, overruns are corrected quickly, and the throughput is gradually increased in order to improve the throughput by a method incorporating the mutual advantages of the first embodiment and the second embodiment. The feature is that correction is made to

As a method of detecting the deceleration start position, the method of judging only the output of the position encoder shown in the conventional example (the method shown in FIG. 12) and the output of the position encoder shown in the embodiment and interpolation are used. Although there is a method of judging the value (the method described in FIG. 8), the above three embodiments for correcting the deceleration start position correspond to any of these methods of detecting the deceleration start position. You can do it. When the method of detecting the deceleration start position of the conventional example and the method of correcting the deceleration start position of the present embodiment are combined, if the resolution of the position encoder is equal to or higher than the accuracy of the correction, the deceleration start of the present embodiment is performed. The correction of the position is effective. Further, when the method of detecting the deceleration start position of the embodiment and the method of correcting the deceleration start position of the embodiment are combined, even if the accuracy of the position encoder is coarser than the accuracy of the correction, the correction is performed because the interpolation value is used. Becomes effective. The accuracy of the correction at this time is defined by the frequency of the timer, but it is easy to increase the frequency of the timer.

In the above embodiment, the optical information recording / reproducing apparatus using the card-shaped information recording medium and the optical head has been described. However, the recording / reproducing method is not limited to the optical method. The present invention can be applied to any type of information recording / reproducing apparatus as long as the method has a track end position. For example, the present invention can be applied to a magnetic information recording / reproducing apparatus using a card-shaped magnetic medium and a magnetic head, a magneto-optical information recording / reproducing apparatus using a magneto-optical card and a magneto-optical head, and a disk having a track end.

[0112]

As described above, according to the present invention,
Since the deceleration start position is sequentially corrected each time scanning is performed according to the speed at the time of entering the low-speed drive start position, even if the deceleration drive is open drive, the frictional resistance state of the support shaft of the movable head 1 and the installation of the device It is possible to automatically converge the deceleration start position to an optimum value so that overrun does not occur due to an environmental change such as an inclination of the device depending on the state.
At the same time, the deceleration start position can be automatically converged to an optimum value so that the low-speed drive section is reduced as much as possible. That is, according to the present invention, overrun can be eliminated and the low-speed drive section can be shortened, so that the scanning throughput can be improved and the time required for recording / reproduction can be shortened.

[Brief description of the drawings]

FIG. 1 is a flowchart showing in detail a deceleration process according to the present invention.

FIG. 2 is a flowchart for explaining a correction method according to the present invention.

3 is a time chart for explaining an operation of the movable head drive circuit shown in FIG. 6 according to the present invention.

FIG. 4 is a specific configuration diagram of the reversing position sensors 3 and 4 used in the present invention.

FIG. 5 is a configuration diagram of an information recording / reproducing apparatus using an optical card according to the present invention and a conventional example.

6 is a block diagram showing in detail a movable head drive circuit of the information recording / reproducing apparatus of FIG. 5 according to the present invention and a conventional example.

FIG. 7 is a time chart for explaining an operation of the movable head drive circuit shown in FIG. 6 according to a conventional example.

8 is a flowchart showing in detail a method of detecting a deceleration start position of the movable head drive circuit of FIG. 6 according to the present invention and a conventional example.

FIG. 9 is a diagram showing an example of an optical card according to the present invention and a conventional example.

FIG. 10 is a block diagram of a movable head drive circuit of the device of FIG. 6B in a conventional example.

FIG. 11 is a time chart for explaining an outline of operations of a movable head drive circuit according to the present invention and a conventional example.

FIG. 12 is a flowchart showing details of a deceleration start target position waiting process in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Movable head 2 Encoder 3, 4 Inversion position sensor 7 Main control device 8 Timer 9 Non-volatile memory 13 Linear motor 14 Shield plate 16 Waveform shaping circuit 54 Movable head drive circuit C Optical card

Claims (9)

[Claims] 1. A recording / reproducing signal is recorded on an information track of the recording medium by reciprocating one of a carriage on which the information recording medium is mounted and a head for recording / reproducing information on the recording medium. In an information recording / reproducing apparatus which scans and records information or reproduces recorded information, a reversal position detecting means for outputting a position signal at a reversal position of the carriage or the head; and a movement of the carriage or the head by a predetermined distance. A moving distance detecting means for detecting, and a rush speed detecting means of the carriage or the head to the reversing position detecting means, wherein a position at which deceleration of scanning is started is automatically determined by an output value of the rush speed detecting means. An information recording / reproducing apparatus, wherein the information recording / reproducing apparatus performs a change correction. 2. The information recording / reproducing apparatus according to claim 1, wherein all or a part of the drive control in deceleration of the carriage or the head is an open drive. 3. The method of automatically changing and correcting the position at which the scanning deceleration is started, wherein the deceleration is started a predetermined distance earlier when the rush speed is higher than a specified speed, and the rush speed is adjusted to a specified speed. 2. The information recording / reproducing apparatus according to claim 1, wherein when the speed is lower than the speed, a change is made so as to start deceleration with a delay of a certain distance. 4. The method of automatically changing and correcting the position at which scanning deceleration is started, wherein a distance obtained by substituting the inrush speed into a correction distance calculation function is used as a correction amount. 2. The information recording / reproducing apparatus according to 1. 5. The method of automatically changing and correcting the position at which the scanning deceleration is started, wherein a dead zone in which no correction is performed when the inrush speed is near a specified speed is provided, and the inrush speed is adjusted to a specified speed. When the inrush speed is lower than a specified speed, the change is made to start deceleration with a certain distance delay when the inrush speed is lower than a prescribed speed. The information recording / reproducing apparatus according to claim 1, wherein the information recording / reproducing apparatus is performed. 6. The inversion position detecting means includes one or more sets of photo-interrupters including a light-emitting diode and a phototransistor, and a light-shielding plate fixed to the carriage or the head includes the light-emitting diode and the photo-interrupter. 2. The information recording / reproducing apparatus according to claim 1, wherein the photointerrupter outputs a position signal at a reversal position of a scanning end by being configured to pass between phototransistors. 7. The moving distance detecting device according to claim 1, wherein the moving distance detecting means detects a moving distance of the carriage or the head by counting an output signal of an encoder provided on the carriage or the head. Information recording and reproducing device. 8. A value of a position at which the scanning deceleration is started,
2. The information recording / reproducing apparatus according to claim 1, wherein the information is managed independently in the forward and reverse directions of scanning. 9. The information recording / reproducing apparatus according to claim 1, wherein an initial value of a position at which the scanning deceleration is started is stored in a nonvolatile memory such as an EEPROM.