JPH07287845A - Information recording/reproducing device - Google Patents

Abstract

PURPOSE:To reliably drive and control an information recording medium such as optical card at a target speed even when the change in the driving voltage of an oscillation wave driving device no longer can increase the moving speed of the medium, by changing the driving frequency. CONSTITUTION:An MPU 4 compares the shuttle moving speed with a preset target speed. If no change occurs in each circuit and the USM after the time of setting, the shuttle moving speed is not different from the target moving speed. When the present shuttle moving speed is lower than the target speed, the MPU 4 instructs a pulse-width changing circuit 8 to expand the pulse width. However, if the shuttle moving speed does not reach the target speed because of the applicable upper limit of driving voltage of the USM 10, the target speed cannot be secured at the preset frequency. In this case, the MPU 4 outputs a voltage to a VCO7 through a D/A converter 6 to increase the moving speed and change the shuttle moving speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to, for example, a light beam from the optical head by relatively reciprocating an optical information recording medium and a head such as an optical head for recording / reproducing. The present invention relates to an information recording / reproducing apparatus which scans an information track of the recording medium and optically records or reproduces information, and more particularly to an information recording / reproducing apparatus using a vibration wave driving device as means for moving the information recording medium.

[0002]

2. Description of the Related Art In recent years, as an information recording / reproducing apparatus for recording / reproducing information on / from a recording medium, an optical information recording / reproducing apparatus for optically recording / reproducing by using a light beam has been attracting attention. There are disc-shaped and card-shaped recording media for optically recording and reproducing information. Among them, the card-shaped recording medium (hereinafter referred to as an optical card) has high productivity, portability, and accessibility. It is excellent and has a wide range of uses.

Information is recorded on a recording medium by scanning an information track with a light beam in the form of minute spots modulated according to the recorded information, and information is recorded as an optically detectable information bit string.

Further, in order to reproduce information from the recording medium,
The information bit string of the information track is scanned with a light beam spot having a constant power such that recording is not performed on the medium,
This is performed by detecting reflected light or transmitted light from the recording medium.

The optical head used for recording / reproducing information on / from the recording medium is relatively movable with respect to the recording medium in the information track direction and in a direction transverse to the information track. The information track is scanned by the spot.

The optical head is provided with a focusing lens for focusing the light beam spot, and an objective lens is used as this lens. This objective lens can move independently in each direction with respect to the optical head main body in the optical axis direction (focusing direction) and in a direction (tracking direction) orthogonal to both the optical axis direction and the information track direction of the recording medium. Is held as. Such holding of the objective lens is generally carried out via an elastic member, and the movement of the objective lens in the above two directions is generally driven by an actuator utilizing magnetic interaction.

FIG. 6 is a schematic plan view of a write-once type optical card. On the information recording surface of the optical card 1000, a number of information tracks 1001 are arranged in parallel in the LF direction.
Further, a home position 1002 which is a reference position for accessing the information track 1001 is provided on the information recording surface of the optical card 1000, and the information track 1001 is arranged in order from the side closer to the home position 1002 to 1001-1, 1001-1.
7 are arranged as shown in FIG.
, The tracking tracks 1003-1, 1003-2, 100 are adjacent to each of these information tracks.
3-3 ... is provided. These tracking tracks are used as guides for auto-tracking (hereinafter abbreviated as AT) that controls the beam spot so that it does not deviate from a predetermined information track during scanning of the optical beam spot during information recording / reproduction.

In this AT control, in the optical head, a deviation (AT error) of the light beam spot from the information track is detected, and this detection information is sent to a tracking actuator for driving the objective lens in the tracking direction. This is performed by a servo system that negatively feeds back the objective lens to the optical head body in the tracking direction (D
Direction) to cause the light beam spot to follow a desired information track.

[0009] The AT control uses the light spot S ₁ and S _3, and so as to utilize the reflected light from the tracking irradiated of the light spot S _1, S _3, the two light spots S Light spot S ₂ located between ₁ and S ₃
The information is recorded and reproduced by. The light sources of the light spots S ₁ , S ₂ and S ₃ may be the same light source or a plurality of light sources, and may be distributed on both sides of the light spot S ₂ due to the interference effect of the diffraction grating arranged between the light source and the objective lens. Light spots S ₃ are formed at intervals.

Further, at the time of recording / reproducing information, when the information track is scanned by the light beam spot, in order to make the light beam into a spot shape of an appropriate size on the optical card surface (focus), the objective lens Autofocusing (hereinafter abbreviated as AF) control is performed.

In this AF control, a deviation (AF error) from the focused state of the light beam spot is detected in the optical head, and this detection signal is negatively fed back to a focusing actuator for moving the objective lens along the optical axis direction. Let
It is performed by moving the objective lens in the focusing direction with respect to the main body of the optical head to focus the light beam spot on the optical card surface.

On the other hand, as a method of relative scanning between the light beam emitted from the semiconductor laser and the optical card, a table that does not move in the track direction of the optical card but can move in a direction crossing the track direction (hereinafter Called a carriage)
An optical card is mounted on the optical head, and a voice coil motor is used to move the optical head main body in a direction parallel to the optical card-shaped track. Further, a vibration wave driving device is used to move the carriage. There is.

In the optical information recording / reproducing apparatus having such a structure, the reason why the carriage is moved in the direction orthogonal to (crossing) the information track is firstly for the purpose of accessing the target information track. Conventionally, the AT control is turned off and scanning is performed at high speed.

Secondly, if the parallelism between the tracks on the optical card and the scanning system in the track direction is deviated (hereinafter referred to as skew) as in the case where the optical card is not properly mounted on the carriage, the AT If scanning is performed in the track direction while the control is on, the objective lens is drive-controlled so as to be displaced with respect to the optical head body, but there is a limit to the amount of displacement of the objective lens with respect to the optical head body. Since the displacement amount may reach the limit during scanning in the track length direction, the displacement of the objective lens with respect to the optical head main body can be allowed by moving the carriage in the direction perpendicular to the track during scanning of the light beam. This is because it is within the range.

Here, the structure and driving principle of the vibration wave driving device will be briefly described.

An elastic body made of a metal having a low vibration damping property, for example, an elastic body formed in an elliptical shape and having a piezoelectric element adhered and fixed to one side by an adhesive or the like is used as a vibrator. It is fixed to the back surface or the side surface together with the piezoelectric element side, and a linear portion on one side of the free end surface side of the elastic body is pressed against a rail-shaped stator extending along the moving direction of the carriage through a pressing means. Contact.

On the other hand, the piezoelectric elements are ¼ (wavelength) apart from each other.
Piezoelectric elements of A and B phases having an odd number of times of the interval are formed, and piezoelectric elements having an interval of λ / 2 and having different polarization processing directions in the thickness direction are formed in each group. Then, by applying a frequency voltage such as an AC voltage having a phase difference of 90 ° to the A and B two-phase piezoelectric element groups,
A standing wave is excited by each of the B2-phase piezoelectric element groups, and a traveling wave that causes an elliptical motion in the plane along the thickness direction is formed on the surface particles of the free end surface of the elastic body by combining them, and the fixed wave is generated. The carriage is moved by friction drive on the child.

FIG. 2 is a block diagram showing an example of an optical card recording / reproducing apparatus for recording / reproducing information on / from the optical card. Reference numeral 200 in the figure denotes an optical card, which is an information recording medium, and 20.
Reference numeral 1 is a carriage (shuttle) for mounting the optical card 200. The shuttle 201 is configured to be movable in the information track crossing direction by driving a vibration wave driving device (hereinafter abbreviated as USM) 202.
By moving the information track with respect to the light beam in the direction crossing the information track under the control of the control circuit 207, the tracking to the target information track and the tracking to the card having a skew angle are prevented. 202 indicates USM. Reference numeral 203 denotes an optical head in which a semiconductor laser that serves as a light source, a photoelectric conversion element, and the like are integrated.
Reference numeral 04 denotes an objective lens that collects a light beam on the optical head 203 and irradiates the optical card 200, and 205 denotes the optical head 203.
Comparing the information track crossing signal output from the comparator, and inputting it to the MPU 206, 206 is an MPU that controls each part of the device, 207 is a USM control circuit that controls the drive of the USM 202 by a command from the MPU 206, and 208 is an optical head The amount of deviation of the objective lens 204 output from 203 from the center position of the optical head 203 is MP
It is a lens position detection circuit for outputting to U206.

Here, assuming that the light beam output from the optical head 203 is on a certain information track on the optical card 200, the so-called seek control for moving this light beam to another information track is a target. If the information track of is outside the movable range of the objective lens 204 in the optical head 203, the MPU 206 informs the USM control circuit 207 of US
Issue a command to drive M202. USM control circuit 2
07 outputs a drive voltage having a drive frequency and amplitude preset in the MPU 206 to the USM 202, and drives the shuttle 201 on which the optical card 200 is mounted. As a result, the information track of the optical card 200 moves relative to the light beam output from the objective lens 204 in the information track crossing direction, and the optical head 203 causes the comparator 20 to move each time the light beam crosses the information track.
5, an information track crossing signal is output to the MPU 206. When the number of input pulses from the comparator 205 reaches the target value, the MPU 206 next time outputs the USM control circuit 20.
7 is instructed to stop driving the USM 202. Therefore, the USM control circuit 207 stops the output of the driving voltage, and the shuttle stops, so that the light beam can be moved to the target information track.

Next, the relative minute movement will be described. When the optical card 200 has a skew angle θ as shown in FIG. 8, the objective lens 204 is limited to the left or right movable range from the center with respect to the optical head 203 while the optical head 203 is scanning the information track in the auto-tracking state. When it moves to the MPU 206, since the current position of the objective lens 204 is input from the optical head 203 to the MPU 206 through the lens position detection circuit 208, the MPU 206 determines from this signal that it is within the movable range limit, and the MPU 206 determines the USM control circuit 207.
In addition, a drive voltage having a drive frequency and an amplitude that makes the moving speed of the shuttle 201 slower than in the preset seek control is output to the USM 202, and the objective lens 204 is located at the center of the optical head 203. Command to move the shuttle 201. When the information track of the optical card 200 starts moving, the objective lens 204 is in the auto-tracking state, and therefore starts moving in the same direction. Therefore, the position of the objective lens 204 is input to the MPU 206 through the lens position detection circuit 208, so that the objective lens 204 is moved to the optical head 203.
When it moves to the center position of, the USM control circuit 207 is instructed to stop the output of the drive voltage to the USM 202.

In this way, the movement of the light beam to the information track and the correction of the positional relationship between the light beam and the information track are performed.

[0022]

However, in the above-mentioned conventional optical information recording / reproducing apparatus, the output voltage to the VCO which generates the voltage source for driving the vibration wave driving apparatus is preset in the MPU. However, since it is not changed at all after setting, if the characteristics of the driving voltage frequency of the vibration wave drive device vs. the rotation speed change for some reason compared to the time of setting, the shuttle to the output voltage to the VCO will change. Even if the MPU gives a command to the pulse width setting circuit to change the shuttle moving speed as a result of the moving speed being set, the shuttle moving speed does not reach the target speed. It had the drawback of increasing the travel time to.

[0023]

According to a first aspect of the present invention, there is provided a head section for recording or reproducing information on an information recording medium having a large number of tracks, and the head section and the information recording medium for the tracks. An oscillatory wave drive means for relatively moving in a direction traversing the optical disk, and for moving the head portion and the information recording medium relatively along an information track when recording or reproducing information on the optical information recording medium. And an optical information recording and / or reproducing apparatus having a control means for operating the auto-tracking control means and driving the vibration wave driving means with a speed control signal depending on the frequency and voltage value of the target speed, A relative movement speed detecting means for detecting a relative movement speed between the head portion and the information recording medium,
The control means drives the vibration wave driving means with a predetermined speed control signal to compare the relative moving speed detected by the relative moving speed detecting means with a target speed, and when the relative moving speed is different from the target speed. If there is no margin in the output of the drive voltage value required to change the drive speed, the drive frequency is shifted in the direction of changing the drive speed to correct the speed control signal to the target speed.

According to this structure, the driving speed does not reach the target speed even if the vibration wave driving device is driven at a predetermined frequency.
Moreover, even if there is no margin in the increase in voltage for increasing the speed, the drive frequency can be shifted to correct the speed control signal to the target speed.

The control means in the above-mentioned claim 1 has a voltage controlled oscillator for outputting a pulse signal at a predetermined frequency in response to a voltage input from the control circuit, and the vibration controlled device is driven by the voltage controlled oscillator. A circuit for changing the frequency of the voltage can be included, and further, a pulse width changing circuit for correcting the output of the pulse signal from the voltage controlled oscillator to a predetermined pulse width, and a pulse from the pulse width changing circuit. It may include a booster for boosting the signal and a sinusoidal waveform.

Further, in the invention described in claim 4, the information recording medium is an optical information recording medium, and the head portion collects the light beam on the optical information recording medium having a large number of tracks by the condensing means. It is an optical head that emits light.

[0027]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of the optical information recording / reproducing apparatus of the present invention.

In FIG. 1, reference numeral 1 is a photodetector for detecting reflected light from two optical spots for tracking control, which are emitted from a semiconductor laser as a light source to an optical card. The photodetector 1 is provided in the fixed optical system shown in FIG. The two light spots for tracking control are generated, for example, by dividing the light beam of the semiconductor laser into a main beam and two side beams in the same manner as in the above-described respective embodiments, and two of these side beams are generated. The beam is applied to two tracking tracks provided on both sides of the information track of the optical card for tracking control.

The photodetector 1 comprises detection pieces 1a and 1b corresponding to two light spots, and the reflected lights of the two light spots reflected from the tracking track are detected by the detection pieces 1a and 1b, respectively. . The detection signals of the detection pieces 1a and 1b are differentially amplified by the differential amplifier 2 and output as an information track crossing signal. When the information track crossing signal is in the autofocus state and the information track moves in either of the crossing directions, the main beam moves the information track to 1
Since a signal is output every time the main passage is made, this signal is binarized by the comparator 3 at a predetermined slice level and input to the shuttle movement speed detection circuit 5. The state is shown in FIG. In this case, since the traveling wave excited by the vibrator of the vibration wave drive device travels in both directions, the carriage movement direction is naturally two directions across the information track. ) And (b), respectively. MPU
Reference numeral 4 is a microprocessor circuit for controlling each part of the apparatus. 5 is a shuttle movement speed detection circuit for detecting the movement speed of the shuttle from the signal from the comparator 3, 6 is a D / A converter for converting the signal output from the MPU 4 to the VCO 7 from a digital signal to 7, and 7 is a D / A converter.
A VCO that outputs a pulse signal having a frequency corresponding to the output voltage from the A converter 6, 8 is a pulse width changing circuit that adjusts the width of the pulse signal output from the VCO 7, and 9 is a USM.
To the ON / OFF of the signal, or by dividing the pulse signal from the pulse width changing circuit 8 to generate a signal whose phase is shifted by 90 degrees, and combining the signals to determine the USM rotation direction. This is a drive circuit for boosting to an appropriate voltage and sending it to the USM 10. The pulse width changing circuit 8 and the drive circuit 9 constitute a voltage variable circuit. The voltage variable circuit has a pulse width changing circuit that corrects the output to a predetermined pulse width in response to the input of the pulse signal from the drive frequency variable circuit and a step-up transformer that performs step-up and sinusoidal waveform conversion. The pulse width of the pulse signal input from the variable circuit can be changed, the pulse signal can be input to the step-up transformer, the step-up and sine waves can be formed, the voltage amplitude can be changed, and the moving speed of the shuttle or the optical head can be adjusted. 10 is a shuttle 201 on which an optical card is placed
Is a vibration wave driving device for moving the vehicle in the transverse direction of the information track.

Next, the operation of this embodiment will be described. First, after the optical card is externally loaded on the shuttle in the apparatus, an optical head (not shown) irradiates a light beam on the information track of the optical card to keep it in an auto-focused state. After that, the MPU 4 measures the shuttle moving speed in order to drive the shuttle at the target speed. First, the MPU 4 passes the D / A converter 6 to the VCO.
A voltage is output to 7 so as to output a pulse signal having a preset frequency. The pulse signal output from the VCO 7 is output as a two-phase drive voltage to the USM 10 through the pulse width changing circuit 8 and the drive circuit 9. Therefore, when the USM 10 starts driving, the information track on the optical card starts to move with respect to the light beam, so that the photodetectors 1a and 1b output signals. This signal is input to the shuttle movement speed detection circuit 5 via the comparator 3. Here, a pulse is input to the shuttle moving speed detecting circuit 5 every time the main beam passes through one information track, so that the shuttle moving speed detecting circuit 5 detects one pulse of the optical card at the interval of the rising edge of the pulse. Calculate the value divided by the width. That is, the moving speed of the shuttle is calculated and output to the MPU 4.

Here, the MPU 4 compares the shuttle moving speed with a preset target speed. Then, if there is no change in each circuit and USM as compared with the setting, it can be said that the shuttle moving speed becomes equal to the target moving speed.

However, if the current shuttle movement speed is higher than the target speed due to some reason, the pulse width is changed by the pulse width changing circuit 8 to reduce the USM drive voltage amplitude, and the shuttle movement is performed. When the speed reaches the target speed, the MPU 4 commands the pulse width changing circuit 8 to hold the current output state to the drive circuit when the target speed is reached.

When the current shuttle moving speed is slower than the target speed, the MPU 4 commands the pulse width changing circuit 8 to widen the pulse width, but the maximum width of the USM drive voltage amplitude has a certain limit. If the shuttle moving speed does not reach the target speed even if the maximum USM drive voltage amplitude is added, the target speed cannot be reliably obtained at the set frequency. In this case, the MPU 4 outputs a voltage to the VCO 7 through the D / A converter 6 so as to increase the shuttle moving speed, and changes the shuttle moving speed.

FIG. 4 shows an example in which the voltage is changed to a low value. After the change, the shuttle moving speed is adjusted again by the pulse width changing circuit 8. If the above operation is repeated, the shuttle movement speed eventually becomes equal to the target speed.
By holding the output voltage to the CO7 and holding the current output state to the drive circuit 9 to the pulse width changing circuit 8, the shuttle can move at the target speed.

FIG. 5 is a flow chart of the speed control by the voltage-frequency change of the vibration wave driving device in the above-mentioned embodiment, taking the case where the shuttle for mounting the optical card is moved with respect to the optical head as an example. The head may be moved with respect to the optical card.

When the shuttle is driven to instruct to start the movement of the optical card (# 1), the VCO 7 generates a signal of the set frequency (# 2), and the pulse width changing circuit 8 outputs the signal of this frequency. Adjust to the voltage value set by (#
3). As a result, the vibration wave driving device is driven at a predetermined frequency, and the shuttle having the optical card mounted thereon starts moving in a predetermined direction.

Therefore, the shuttle moving speed detecting circuit 5 detects the moving speed of the shuttle from the number of pulses generated each time the information track crosses the optical head (# 4), and compares the detected moving speed with the target speed. (# 5).

In # 5, if the detected moving speed is faster than the target speed, an operation of decreasing the output voltage value in the pulse width changing circuit 8 by a predetermined amount is performed until it becomes equal to or slower than the target speed. (# 6).

Here, in the case of slowing the moving speed of the shuttle, it is considered that when the voltage value becomes close to 0, the speed also becomes close to 0. Therefore, the frequency adjustment is not taken into consideration.

Then, the detected moving speed is again compared with the target speed (# 7).

Here, when the detected moving speed is compared with the target speed, it is determined in # 5 that the detected moving speed is not higher than the target speed. Therefore, if the detected moving speed is not lower than the target speed, that is, If the detected moving speed is equal to the target speed, the process proceeds to step # 13 to end the operation of this flowchart.

On the other hand, when the detected moving speed is slower than the target speed, it is judged whether or not the voltage value of the pulse width changing circuit 8 is the maximum output value, and if it is not the maximum output value, the voltage value is increased by a predetermined amount ( # 9), # 4 and subsequent operations are executed again. Also,
If the voltage value is the maximum output value, proceed to # 10 to change the frequency.

The relationship between the drive frequency and the drive speed in the oscillatory wave drive device is such that the speed at the resonance frequency is the highest and the speed becomes slower in the direction in which the frequency becomes higher and in the direction in which the frequency becomes lower. is doing. For this reason,#
In 10, it is judged whether the current drive frequency exists in the above characteristic curve or in the above characteristic curve, and if it exists in the above characteristic curve, the driving speed is increased by lowering the frequency. The frequency is reduced by a predetermined amount in # 11, and
Perform the following operations again. If it exists in the characteristic curve of, since the driving speed is increased by increasing the frequency, the driving frequency is increased by a predetermined amount in # 12, and the operations in and after # 4 are executed again.

That is, even if the driving voltage value is the maximum output value, the driving speed can be changed to the target speed by changing the driving frequency.

In the above embodiment, an optical card is used as the information recording medium, but a magnetic recording medium may be used.

Although the carriage is moved in the information track crossing direction in the above embodiments, the carriage may be fixed in the information track crossing direction and the optical head may be moved in the information track crossing direction by driving the USM. .

Further, although the above-mentioned embodiment has exemplified the device capable of both recording and reproducing, the present invention is not limited to this and can be applied to a device capable of only recording or reproducing. May be.

[0048]

According to the present invention, even if the moving speed of the information recording medium such as the optical card cannot be increased due to the change of the driving voltage of the vibration wave driving device, the driving frequency is changed to reach the target speed. Control signals can be corrected,
Even if the control signal of the vibration wave drive device deviates from the target speed due to a change in the environment, it is possible to reliably correct and drive and control the information recording medium at the target speed.

[Brief description of drawings]

FIG. 1 is a block diagram of an optical information recording / reproducing apparatus showing a first embodiment of the present invention.

FIG. 2 is a block diagram of a conventional optical information recording / reproducing apparatus.

FIG. 3 is a waveform diagram showing a relationship between a track crossing signal and a slice level in forward and reverse directions of the vibration wave driving device of the first embodiment.

FIG. 4 is a diagram showing the relationship between changes in the set voltage of the vibration wave driving device and the shuttle moving speed change range in the first embodiment.

FIG. 5 is a flowchart showing an operation in the first embodiment.

FIG. 6 is a schematic plan view of a write-once optical card.

FIG. 7 is an enlarged plan view of a track of an optical card.

FIG. 8 is a plan view showing a skew angle.

[Explanation of symbols]

 1 Photodetector 2 Operational Amplifier 3 Comparator 4 MPU 5 Shuttle Moving Speed Detection Circuit 6 D / A Converter 7 VCO 8 Pulse Width Change Circuit Drive Circuit 10 USM

Claims (4)

[Claims] 1. A head section for recording or reproducing information on an information recording medium having a large number of tracks, and a vibration wave driving means for relatively moving the head section and the information recording medium in a direction crossing the tracks. When recording or reproducing information on or from the optical information recording medium, the head portion and the information recording medium are relatively moved along the information track, and the auto-tracking control means is brought into an operating state to cause the vibration. Information recording and / or control means for driving the wave driving means with a speed control signal depending on the frequency and voltage value of the target speed
Alternatively, the reproducing apparatus has a relative moving speed detecting means for detecting a relative moving speed of the head portion and the information recording medium, and the control means drives the vibration wave driving means with a predetermined speed control signal. Then, the relative movement speed detected by the relative movement speed detecting means is compared with the target speed, and if the relative movement speed is different from the target speed, if there is no margin in the output of the drive voltage value required for changing the drive speed, the drive is performed. An information recording / reproducing apparatus characterized in that a frequency is shifted in a direction of changing a driving speed to correct a speed control signal to a target speed. 2. The control means according to claim 1, further comprising a voltage-controlled oscillator that outputs a pulse signal at a predetermined frequency in response to a voltage input from the control circuit, and the voltage-controlled oscillator causes the oscillatory wave drive device to operate. An information recording / reproducing apparatus characterized in that the frequency of a drive voltage is changed. 3. The pulse width changing circuit according to claim 2, wherein the pulse width changing circuit corrects an output of the pulse signal from the voltage controlled oscillator so as to have a predetermined pulse width, and the boosting of the pulse signal from the pulse width changing circuit. An information recording / reproducing apparatus, comprising: and a step-up transformer having a sine waveform. 4. The information recording medium according to claim 1, 2 or 3, wherein the information recording medium is an optical information recording medium, and the head unit collects the light beam on the optical information recording medium having a large number of tracks by a condensing unit. An information recording / reproducing apparatus, which is an optical head for emitting light.