JPH0754607B2 - Optical recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention records or reproduces information by relatively reciprocating a card-shaped information recording medium and a head section for processing information on this recording medium. The present invention relates to an optical recording / reproducing device that performs

[Prior Art] There are magnetic and optical methods as the information recording / reproducing apparatus as described above, but in recent years, an optical method is drawing attention. As an apparatus for recording / reproducing information using a light beam, an optical disk that rotates a disk-shaped recording medium,
There is an optical card that reciprocates a card-shaped recording medium, and an optical tape or the like. Each of these devices has merits and demerits, and they are used properly depending on the purpose, application, etc. Among them, the optical card has advantages such as ease of manufacturing, portability, and accessibility. It is spreading.

There are various possible modes for scanning the light beam on the optical card on the card. The irradiation position of the light beam is relatively linearly moved on the recording medium to reciprocate and the beam irradiation position is reciprocated. The configuration in which scanning is performed by relatively moving in a direction orthogonal to is advantageous in that the mechanism is simple and accuracy is easy to obtain.

The outline of the control of the reciprocating movement of the card A in such an information recording / reproducing apparatus is as shown in FIG. That is, the motor 1 for driving the card A in the information track direction is provided with an encoder 2 or a tacho-generator for speed detection, and in the case of the encoder 2, its output is added to the frequency / voltage converter 3 to obtain speed data. Is sent to the amplifier 4 as a voltage signal. If a tachogenerator is used, its output is applied directly to the amplifier 4. The motor 1 is connected to the feed roller 5 via a gear or the like, and the card A is transported by the feed roller 5 and the idling roller 6. The data to be recorded on the card A is modulated by the laser diode in the optical head 7 according to the data sent to the optical head 7, and the medium Ad of the card A is scanned to record the data Ad. The signal obtained by amplifying the error component with respect to the reference speed by the amplifier 4 is connected to the loop filter 13, and the output of the loop filter 8 is the interface 9
Based on a command from the MPU 10 via the, the voltage is applied to the driver 12 that supplies a drive current to the motor 1 through the polarity conversion circuit 11 that switches the voltage polarity according to the traveling direction of the motor 1.
Reference numerals 13 and 14 denote end face detectors of the card A. When the card A is sent and the right end or the left end of the card A is detected, information is sent to the MPU 10 through the interface 9. Based on the internal memory and a program based on this information, the MPU 10 sets the feed direction of the motor 1 by the polarity conversion circuit 11, the gain of the amplifier 4 by the gain switching circuit 15, and the time constant switching circuit 16 as a speed command to the frequency / voltage converter 3. Controls such as switching.

[Problems to be Solved by the Invention] However, in the recording / reproducing apparatus that performs such reciprocal scanning,
The control becomes an open loop state at the reversal portions at both ends of the card A, and it is difficult to obtain an accurate stop state at the reversal position and the end of the recording area. That is, the card edge detector 1
When the outputs of 3 and 14 are given to the MPU 10 through the interface 9, the MPU 10 outputs the braking command of the motor 1 to the driver 12, but the stop position of the card A differs depending on the mechanical resistance at that time. , The starting point of data Ad will not be determined. This means that the recording area of card C
Not only can Aa not be effectively used to the maximum extent, but there is a drawback that the seek of the recording track cannot be performed accurately at the end of the recording area Aa.

Thus, since the stop position of the light beam outside the recording area on the track, that is, the starting position of the card drive for the next recording or reproducing is not determined, the card for recording or reproducing from the position on this track is not determined. The distance from the start of driving until the required constant speed accuracy is obtained, that is, the rising distance can be guaranteed to be a certain value, but the data start point on the track is not fixed, and the stop position is closest to the center of card A. Predict,
The data recording area must be inside the rising distance.

To explain this with reference to FIG. 3, A is a card,
Reference characters a and a'are tracks on the card A, and recording information b is recorded between the tracks a and a '. The end surface of the card A is h, and the end points of the tracks a and a'are e. B and C indicate the position and speed on the surface of the card A, and the arrows indicate the relative moving directions of the light beams. However, the direction in which the card A actually moves is opposite to the direction of this arrow. B
When the card A is braked at the position S, the card A approaches the end point e when the mechanical load is small and stops at the position S ′, but when the mechanical load is large, the end point e as in C is generated. The vehicle is stopped at a position S ″ apart from the position S. Various braking methods can be considered, such as a short circuit of the armature coil of the motor 1 and a mechanical braking method.

Next, the optical head 7 may be moved in the vertical direction or a jump command may be issued to a tracking servo circuit (not shown) to transfer the light beam to another track, but the track is not transferred. In addition, verification of the same track, that is, confirmation of data by reproduction after recording may be performed. Since the movement of the light beam in the track direction at the time of this track transfer is slight, it is neglected. Then, the positions S ′ and S ″ at B and C become the starting points, and the leftward arrows along the lower paths, respectively. Direction of card A
The movement of the light beam is started in the direction opposite to the moving direction of the light beam. In this case, a problem is that the positions of d'in B and d "in C on the card A where the constant speed required for reproduction is obtained are different, and the movement of the card A until the constant speed is reached. Even if the amounts are the same, the recording area moves to the central portion of the card up to d ″ in C. Therefore, the information recording area is limited to the inside of d "on the card A. One method of expanding this recording area is to increase the speed of the motor 1 to sharpen the speed rising from the position S" to d ". The other is to increase the starting torque of the card A, and the other one is to brake and start the cards a and a'of the card A outside the end point e, that is, on the right side. , There are disadvantages such as transient large current and vibration of the power supply, and the latter causes tracking off once,
There is a time for re-pull-in, which causes a disadvantage of reduced throughput.

[Object of the Invention] An object of the present invention is to eliminate the drawbacks of the above-described method such as increase of the starting torque of the motor, tracking re-pull-in, etc. An object of the present invention is to provide an optical recording / reproducing device that can be used.

[Summary of the Invention] The gist of the present invention for achieving the above-mentioned object is to repeatedly and repeatedly reciprocate a light beam and the medium by an actuator along the track of a card-shaped optical recording medium having an information track. In an optical recording / reproducing device for recording and / or reproducing information by scanning,
Speed servo control means for speed servo-controlling the actuator so that the relative speed of the light beam and the medium follows a target relative speed when the light beam scans a portion of the medium where information is recorded. And position servo control means for position servo-controlling the actuator so that the light beam stops at a fixed position on the medium when reversing the scanning direction in the reciprocal scanning. Means for detecting a relative position between the light beam and the medium to generate a relative position signal, means for generating a target position signal indicating a target stop position of the light beam on the medium, the relative position signal and the target Means for detecting a position error signal indicating a difference from the position signal, and a drive signal indicating the position error signal for providing to the actuator, It is an optical recording and reproducing apparatus characterized by comprising a means for driving the actuator so that the difference signal becomes zero.

Embodiments of the Invention The present invention will be described in detail based on the embodiment shown in FIG. The same reference numerals as those in FIG. 2 indicate the same members.

In FIG. 1, a motor 1 for driving the feed roller 5
A rotary encoder 20 is provided coaxially with the rotary encoder 20, and the output of the rotary encoder 20 is connected to the frequency / voltage converter 3. The output of the frequency / voltage converter 3 is connected to the motor 1 via the loop filter 8, the amplifier 4, the polarity conversion circuit 11, the switch SW1, and the driver 12. Edge detector
The outputs of 13 and 14 are connected to the interface 9 via switches SW2 and SW3, respectively. Further, a potentiometer 21 for detecting the position of the feed roller 5 is attached, the output of which is connected to an input end of a differential amplifier 22, and switches SW2, S are connected to the other input ends of the differential amplifier 22.
Reference voltages Vp1 and Vp2 are input via W3. The output of the differential amplifier 22 is connected to the motor 1 via the driver 12 as well as the output from the polarity conversion circuit 11 via the filter 23 and the switch SW4. The MPU 10 is connected to the interface 9, and the output of the interface 9 is a switch SW.
While operating 1 to SW4, it is output to the frequency / voltage converter 3 via the time constant switching circuit 16 and is output to the amplifier 4 via the gain switching circuit 15.

When the card A is recording or reproducing at a constant speed, the time constant of the frequency / voltage converter 3 and the gain of the amplifier 4 are set to desired values from the MPU 10 through the interface 9. The traveling direction of the card A is judged from the outputs of the card end surface detectors 13 and 14 before that time, and the polarity conversion circuit 11 is instructed. At this time, the switch SW1 is turned on,
The driver 12 is operated in a constant speed control loop. Next, the card A moves and the card end face detector 13 switches the switch SW2,
When information is output to MPU10 via interface 9, M
PU10 turns on switch SW4 at position S in FIG. 2D and turns off switch SW1 to switch to position servo. The reference voltage Vp1 is set to the output voltage of the potentiometer 21 corresponding to the beam S'of the card A.
1 is applied to one input of the differential amplifier 4 through the switch SW2, but the switch SW3 is off at this time.
Therefore, the card A is driven by the position error signal output from the differential amplifier 4, that is, the card A is driven by the driver 12 supplying the motor 1 with a drive signal indicating the position error signal, and the beam is moved to the position S at the position D. When it reaches ′, the position error signal becomes zero and stops. Next, the optical head 7 performs an operation such as jumping to another track or reproducing the same track again, and the MPU 10 issues a command to drive the card A in the reverse direction. That is, switch SW4 is turned off,
The switch SW1 is turned on, the polarity is switched by the polarity switching circuit 11, and constant speed feeding is performed. At this time, the constant velocity is obtained by the rising from the position S ′ in FIG. 2D to d. Therefore, the recording area Aa may be inside the d, that is, on the side of the central portion from the position S, and the recording area is secured like the recording information b in FIG. 2E.

The card A is then sent to the right side, and at the position S on the left side of the card, the position control is switched again by the output of the end face detector 14,
A preset voltage Vp2 corresponding to the potentiometer 21 at the position S on the left side of the card is applied to one input of the differential amplifier 4 via the switch SW3, and the position S'on the left side of the card A is set.
Stop at. In FIG. 2D, the stop distance S-S 'is determined from the maximum stop distance, so that it does not extend outside from the tangent point e of the tracks a and a'. It is also possible to apply the reverse rotation voltage to the motor 1 for a short time during the braking period as required.

Although the analog position servo system using the potentiometer 21 has been described in this embodiment, the rotary encoder may be a two-phase output and the data in the feeding direction of the card A may also be output to constitute a known digital position servo system. It is possible.

EFFECTS OF THE INVENTION As described above, in the optical recording / reproducing apparatus according to the present invention, the non-recording area is reduced to the maximum stop distance if the maximum stop distance required to stop the recording medium is longer than the rising distance. The recording area is secured by this, and as a means to realize this, the position at the time of starting the card is set to the track's tangent point with high accuracy in advance by the control by the position servo to ensure the constant speed. It is possible to substantially enlarge the area where the above is obtained, that is, the recording area. Also, since the stopping distance can be shortened by adding reverse torque to the motor for a short time, using mechanical braking together, etc., the maximum stopping distance can also be made shorter than the starting distance. The recording area will be limited only by the distance of the maximum rise at both ends of.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram showing an embodiment of an optical recording / reproducing apparatus according to the present invention, and FIG. 2 is a configuration diagram of a conventional example, and FIG.
The figure is an illustration of card feeding. Reference numeral 1 is a motor, 3 is a frequency / voltage converter, 4 is an amplifier, 5 is a feed roller, 7 is an optical head, 8 is a loop filter, 9 is an interface, 10 is an MPU, 11 is a characteristic switching circuit, and 12 is a driver. , 13 and 14 are end face detectors, 15 is a gain switching circuit, 16 is a time constant switching circuit, 20 is a rotary encoder, 21 is a potentiometer, 22 is a differential amplifier, and 23 is a filter.

Claims (1)

[Claims] 1. Recording and / or reproducing of information is performed by reciprocally reciprocally scanning a light beam and the medium with an actuator along the track of a card-shaped optical recording medium having an information track. In the optical recording / reproducing apparatus, the speed of the actuator is set so that the relative speed of the light beam and the medium follows a target relative speed when the light beam scans a portion of the medium where information is recorded. A speed servo control means for servo-controlling, and a position servo control means for position-servo-controlling the actuator so that the light beam stops at a fixed position on the medium when the scanning direction is reversed in the reciprocal scanning. The position servo control means detects a relative position between the light beam and the medium and generates a relative position signal; Means for generating a target position signal indicating a target stop position of the beam on the medium; means for detecting a position error signal indicating a difference between the relative position signal and the target position signal; and driving for indicating the position error signal. Means for providing a signal to the actuator and driving the actuator so that the position error signal becomes zero.