Abstract:
An optical information recording and reproducing method and device, whereby it is possible to prevent reduction in information recording capacity of an optical card and increase in recording and reproduction time due to track jump operations, and there is no occurrence of track jumping errors due to oscillations associated with acceleration and deceleration of the relative speed of movement between the optical card and an optical head. A region where the optical head and optical card are moved at a constant speed relative to each other is provided in the acceleration or deceleration of the relative speed of movement, and a track jump operation is implemented in this region.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an optical information recording and reproducing method and device, and more particularly, to an optical information recording and reproducing method and device, whereby improvement can be made in the performance of track jump operations of a light beam spot to a desired information track on a card-shaped optical recording medium, whereon a plurality of information tracks are formed mutually in parallel. 
     2. Description of the Related Art 
     In many optical information recording and reproduction devices, whereby information is recorded onto and reproduced from an optical information recording medium whilst causing the recording medium to move at high speed relative to an optical head emitting a light beam spot, a card-shaped recording medium, in other words, a recording medium called an optical card, is used. 
     Here, FIG. 6 shows the composition of a general optical card. 
     As FIG. 6 shows, the optical card  500  comprises several thousand or several ten thousand information tracks  504  formed mutually in parallel in an information recording region  501  thereof, and information is recorded by shining a light beam spot onto the central region  502  (region represented by p×q surface area) of these information tracks  504  to form pits, and information is reproduced by detecting the presence or absence of pits from the reflected light of the light beam spot. 
     In addition to forming pits when recording information on the central region  502 , pre-formatted information, such as address information for specifying data groups or information tracks  504  required for acquiring bit synchronization, is recorded previously by creating pits. 
     On the other hand, the end regions  503  (regions represented by r×q surface area) of the information tracks  504  are regions for accelerating and decelerating in order that the optical card is moved at a constant speed relative to the optical head, so no pits are formed in these regions. 
     FIG. 7 is a diagram giving a partial enlarged illustration of the information recording region  501  of the optical card  500 . 
     Information tracks  504  ( 504 - 1 ,  504 - 2 ,  504 - 3 ) and guide tracks  505  ( 505 - 1 - 505 - 4 ) are formed on the information recording region  501 , and pre-formatted data pits  506  constituting pre-formatted data, such as address information, and the like, and recording pits  507  constituting data recorded by the user are formed on the information tracks  504 , the absence or presence or these pre-formatted data pits  506  or recording pits  507  representing the respective data types. 
     The guide tracks  505  are regions of different reflectivity to the information tracks  504 , and they are used for autotracking (hereinafter, abbreviated as AT) control in order that the optical information recording and reproduction device does not deviate from the information track  504  when scanning a desired information track  504 . 
     FIG. 8 is a block diagram showing the composition of an optical information recording and reproduction device, and FIG. 9 is an approximate diagram showing the composition of an optical head. 
     In FIG. 8, the optical information recording and reproduction device  510  comprises: a CPU (Central Processing Unit)  511  for overall control of the device; an MPU (Microprocessor Unit)  512  for controlling the section relating to the recording and reproduction operations of the device, on the basis of the control implemented by the CPU  511 ; a modulating and demodulating circuit  513  for modulating data being recorded and demodulating data being reproduced; an optical head  514  for creating and detecting recording pits  507 , and the like; a y-direction drive motor  515  which drives the optical head  514  reciprocally in the y direction; an x-direction drive motor  516  which drives the optical card  500  reciprocally in the x direction; a track jump circuit  517  for controlling track jumping; an AF/AT control circuit  518  for performing autofocussing (hereinafter, abbreviated as AF) control and AT control such that a focused light beam spot is shined onto the surface of the light card  500  at all times, even if there are fluctuation in this surface; and a movement speed detecting circuit  519  for detecting the speed of movement of the optical card  500 . 
     Furthermore, as shown in FIG. 9, the optical head  514  comprises: a semiconductor laser  541 , collimator lens  542 , diffraction grating  543 , beam splitter  544 , object lens  545 , light receiving lens  546 , photoreceptor  547 , and actuator  548 . Laser light output from the semiconductor laser  541  is formed into parallel light by the collimator lens  542  and split by the diffraction grating  543  into three beams, which are shined via the beam splitter  544  and object lens  545  onto the optical card  500  as beam spots  550 . The reflected light from the beam spots  550  shined onto the optical card  500  passes through the object lens  545 , beam splitter  544  and light receiving lens  546  and is converted to an electrical signal by the photoreceptor  547 . Since one of the three beam spots shined onto the optical card  500  is shined onto an information track  504 , and the other two beam spots are shined onto the guide tracks  505  on either side of this information track  504 , the reflected light, in other words, the signal converted to an electrical signal by the photoreceptor  547 , contains a focussing control signal and tracking control signal in addition to a data signal. In order for the optical recording and reproduction device  510  to record or reproduce information on a desired information track  504 , the information track  504  must be selected accurately. In general, the operation of selecting an information track is call track access, or simply access, and it comprises the operations of moving the whole optical head  514  in a direction perpendicular to the information track  504 , and moving a portion of the optical system in the optical head  514 , for instance, the object lens  545 , in a direction perpendicular to the information tracks  504  by means of an actuator  548 , the latter operation also being called a track jump operation. 
     Here, a first example relating to a conventional track jump operation, wherein the relative speed of movement between the optical card and optical head is constant, is described with reference to FIG.  10  and FIG.  11 . 
     FIG. 10 is a diagram illustrating the relationship between the relative speed of movement of the optical card and time, and their relationship to the pulse voltage applied by the optical information recording and reproduction device to the actuator for moving the optical card and time. FIG. 11 is a flowchart showing the sequence of a track jump operation in an optical information recording and reproduction device. 
     In order to record or reproduce information to or from the optical card, the optical recording and reproduction device  510  starts an operation whereby the optical card  500  is moved reciprocally by driving the x direction drive motor  516 , such that the optical card  500  and optical head  514  move relative to each other (step  601  in FIG.  11 ), and the MPU  512  applies an acceleration pulse (voltage V 1 ) to the x direction drive motor  516  to accelerate the relative speed of movement of the optical card  500  to a prescribed speed v 1  (step  602 ; section a in FIG.  10 ). 
     If the movement speed detecting circuit  519  detects that the relative speed of movement of the optical card  500  has reached a prescribed speed v 1 , (hereinafter, all detection of the relative speed of movement of the optical card  500  is carried out by the movement speed detecting circuit  519 ), then the optical recording and reproduction device  510  applies a constant-speed pulse (voltage V 2 ) for maintaining that speed to the x direction drive motor  516  (step  603 ; section b), and performs a recording operation for recording information modulated by the modulating and demodulating circuit  513  onto a prescribed information track  504  of the optical card  500 , or a reproduction operation for reproducing information recorded on a prescribed information track  504  of the optical card  500  and demodulating the information by means of the modulating and demodulating circuit  513 , in a state where the relative speed of movement of the optical card  500  is constant (step  604 ; section b). 
     When the recording or reproduction operation is completed, the optical information recording and reproduction device  510  actuates the AF/AT control circuit  518 , opening the AT control loop and halting AT control, (step  605 , section b), whilst maintaining the relative speed of movement of the optical card  500  at v 1 . 
     The AT control is halted in this way because the object of AT control is to make the light beam spot continue shining on the desired information track, and therefore when performing a track jump for moving the light beam spot to a different information track  504 , the AT control and track jump operations conflict with each other. 
     When the AT control is halted, the track jump circuit  517  applies a track jump pulse to the actuator  548  which moves the object lens  545 , thereby causing the object lens  545  to move in a direction perpendicular to the information tracks  504  (step  606 ; section b). 
     Thereupon, the track jump circuit  517  applies a brake pulse of opposite polarity to the track jump pulse to the actuator  548 , (step  607 , section b), thereby decelerating the speed of movement of the object lens  545  and causing the object lens  545  to come to rest in a position whereby the light beam spot shines on the desired information track  504 . 
     When the point of illumination of the light beam spot moves to the desired information track  504 , the AF/AT control circuit  518  closes the AT control loop and starts AT control (step S 608 , section b), and the MPU  512  applies a decelerating pulse (voltage −V 1 ) to the x direction drive motor  516 , thereby decelerating the relative speed of movement of the optical card  500  (step  609 , section c). This decelerating pulse is applied until the relative speed of movement of the optical card  500  reaches zero (NO at step  610 ), and when this relative speed of movement reaches zero (YES at step  610 , section d), an accelerating pulse (voltage −V 1 ) is applied to the x direction drive motor  516  and the relative speed of movement of the optical card  500  is accelerated until it reaches a prescribed speed −v 1  (step  611 , section e). Here, the accelerating pulse applied is an accelerating pulse of opposite polarity to the accelerating pulse applied at step  602 , and therefore the direction of the relative movement of the optical card  500  is opposite to the direction of movement when in the acceleration operation in step  602 . 
     When the relative speed of movement of the optical card  500  reaches a prescribed speed −v 1 , the MPU  512  applies a constant-speed pulse (voltage −V 1 ) for maintaining that speed to the x direction drive motor  516  (step  612 , section f), and the optical head  514  records or reproduces information to or form a desired information track  504  of the optical card  500  (step  613 , section f), whereupon the AF/AT control circuit  518  closes the AT control loop and halts AT control (step  614 , section f). 
     When the AT control is halted, the track jump circuit  517  applies a track jump pulse to the actuator  548 , thereby causing the object lens  545  to move in the direction perpendicular to the information tracks  504  (step  615 , section f). 
     Thereupon, the track jump circuit  517  applies a brake pulse of opposite polarity to the track jump pulse to the actuator  548  (step  616 , section f), thereby decelerating the speed of movement of the object lens  545  and causing the object lens  545  to come to rest in a position whereby the light beam spot shines onto the desired information track  504 . 
     When the point of illumination of the light beam spot has moved to the desired information track  504 , the AF/AT control circuit  518  closes the AT control loop and starts AT control (step  617 , section f). 
     Next, the MPU  512  applies a decelerating pulse (voltage V 1 ) to the x direction drive motor  516 , decelerating the relative speed of movement of the optical card (step  618 , section g), and when the relative speed of movement reaches zero (YES at step  619 , section h), the process returns to step  602  and an accelerating pulse is applied again to the x direction drive motor  516  (step  602 , section i). 
     These operations are repeated until the optical recording and reproduction device  510  has completed the prescribed recording or reproduction operation. 
     Next, a case where a track jump operation is carried out in a state where the relative speed of movement between the optical card and optical head is zero, as proposed in Japanese Patent Examined Publication No. 6-9088, is described with reference to FIG.  10  and FIG. 12, as a second example of a conventional track jump operation. 
     FIG. 12 is a flowchart showing the sequence of a track jump operation in an optical recording and reproduction device. 
     When the optical recording and reproduction device  510  starts an operation whereby the optical card  500  and optical head  514  are moved relative to each other by moving the optical card  500  reciprocally, in order to record and reproduce information to and from the optical card  500 , (step  701  in FIG.  12 ), the MPU  512  applies an accelerating pulse (voltage V 1 ) to the x direction drive motor  516 , thereby accelerating the speed of relative movement of the optical card  500  to a prescribed speed v 1  (step  702 ; section a in FIG.  10 ). 
     When the relative speed of movement of the optical card  505   505  reaches the prescribed speed v 1 , the MPU  512  applies a constant-speed pulse (voltage V 2 ) for maintaining that speed to the x direction drive motor  516  (step  703 , section b), and the optical head  514  records or reproduces information to or from a prescribed information track  504  of the optical card  500  (step  704 , section b). 
     When the optical card  500  and optical head  514  assume a prescribed positional relationship, the MPU  512  applies a decelerating pulse (voltage −V 1 ) to the x direction drive motor  516 , thereby decelerating the relative speed of movement of the optical card  500  (step  705 , section c). This decelerating pulse is applied until the relative speed of movement of the optical card  500  reaches zero (NO at step  706 ), and when the relative speed of movement reaches zero (YES at step  706 , section d), the AF/AT control circuit  518  opens the AT control loop and halts AT control (step  707 , section d). 
     When the AT control is halted, the track jump circuit  517  applies a track jump pulse to the actuator  548  which drives the object lens  545 , thereby moving the object lens  545  in a direction perpendicular to the information track  504  (step  708 , section d). 
     Next, the track jump circuit  517  applies a brake pulse of opposite polarity to the track jump pulse to the actuator  548  (step  709 , section d), thereby decelerating the speed of movement of the object lens  545 , such that the object lens comes to rest in a position where the light beam spot shines onto the desired information track  504 . 
     When the illumination point of the light beam spot has moved to the desired information track  504 , the AF/AT control circuit  518  closes the AT control loop and starts AT control (step  710 , section d), and the MPU  512  applies an accelerating pulse (voltage −V 1 ) to the x direction drive motor  516 , thereby accelerating the relative speed of movement of the optical card  500  to the prescribed speed−v 1 (step  711 , section e). Here, the accelerating pulse applied is of opposite polarity to the accelerating pulse applied at step  702 , and the direction of relative movement of the optical card  500  is opposite to the direction of movement due to the acceleration in step  702 . 
     When the relative speed of movement of the optical card  500  has reached a prescribed speed−v 1 , the MPU  512  applies a constant-speed pulse (voltage−v 2 ) for maintaining this speed to the x direction drive motor  516  (step  712 , section f), and the optical head  514  records or reproduces information to or from a desired information track  504  of the optical card  500  (step  713 , section f). 
     When the optical card  500  and optical head  514  assume a prescribed positional relationship, the MPU  512  applies a decelerating pulse (voltage V 1 ) to the x direction drive motor  516 , decelerating the relative speed of movement of the optical card  500  (step  714 , section g), and when the relative speed of movement reaches zero (YES at step  715 , section h), the AF/AT control circuit  518  opens the AT control loop and halts AT control (step  716 , section h). 
     When the AT control is halted, the track jump circuit  517  applies a jump track pulse to the actuator  548 , thereby causing the object lens  545  to move in a direction perpendicular to the information tracks  504  (step  717 , section h). 
     Next, the track jump circuit  517  applies a brake pulse of opposite polarity to the track jump pulse to the actuator  548  (step  718 , section h), decelerating the speed of movement of the object lens  545  such that it comes to rest in a position where the light beam spot is shined onto the desired information track  504 . 
     When the illumination point of the light beam spot has moved to the desired information track  504 , the AF/AT control circuit  518  closes the AT control loop and starts AT control (step  719 , section h), and the process returns to step  702 , where the MPU  512  applies an accelerating pulse to the x direction drive motor  516  (step  702 , section i). 
     These operations are repeated until the optical recording and reproduction device  510  has completed the prescribed recording and reproduction operations. 
     Next, a case where a track jump operation is implemented when the relative speed of movement between the optical card and optical head is accelerating or decelerating, as disclosed in Japanese Patent Unexamined Publication No. 5-282682, is described with reference to FIG.  10  and FIG. 13 as a third example of a conventional track jump operation. 
     FIG. 13 is a flowchart showing the sequence of a track jump operation in an optical recording and reproduction device. 
     When an operation is started whereby the optical card  500  and optical head  514  are moved relative to each other by moving the optical card  500  reciprocally, in order that the optical recording and reproduction device  510  records or reproduces information to or from the optical card  500  (step  801  in FIG.  13 ), the MPU  512  applies an accelerating pulse (voltage V 1 ) to the x direction drive motor and accelerates the relative speed of movement of the optical card  500  to a prescribed speed v 1  (step  802 , section a in FIG.  10 ). 
     Here, in the period until the relative speed of movement of the optical card  500  reaches the speed v 1 , the AF/AT control circuit  518  opens the AT control loop and halts AT control (step  803 , section a), and the track jump circuit  517  applies a track jump pulse to the actuator  548 , causing the object lens  545  to move in a direction perpendicular to the information tracks  504  (step  804 , section a). 
     Thereupon, the track jump circuit  517  applies a brake pulse of opposite polarity to the track jump pulse to the actuator  548  (step  805 , section a), thereby decelerating the speed of movement of the object lens  545  such that it comes to rest in a position where the light beam spot shines onto the desired information track  504 . 
     When the illumination point of the light beam spot has moved to the desired information track  504 , the AF/AT control circuit  518  closes the AT control loop and starts AT control (step  806 , section a). 
     Next, when the relative speed of movement of the optical card  500  reaches the prescribed speed v 1 , the MPU  512  applies a constant-speed pulse (voltage V 2 ) for maintaining this speed to the x direction drive motor  516  (step  807 , section b), and the optical head  514  records or reproduces information to or from a desired track  504  of the optical card  500  (step  807 , section b). 
     When the optical card  500  and optical head  514  assume a prescribed positional relationship, the MPU  512  applies a decelerating pulse (voltage −V 1 ) to the x direction drive motor  516 , thereby decelerating the relative speed of movement of the optical card  500  (step  809 , section c). This decelerating pulse is applied until the relative speed of movement of the optical card  500  reaches zero (NO at step  810 ), and when the relative speed of movement reaches zero (YES at step  810 , section d), the MPU  512  applies an accelerating pulse (voltage −V 1 ) to the x direction drive motor  516 , accelerating the relative speed of movement of the optical card  500  to a prescribed speed−v 1  (step  811 , section e). 
     In this case, the accelerating pulse applied is of opposite polarity to the accelerating pulse applied in step  802 , and the direction of relative movement of the optical card  500  is opposite to the direction of movement inducted by the acceleration in step  802 . 
     Here, in the period until the relative speed of movement of the optical card  500  reaches the speed−v 1 , the AF/AT control circuit  518  opens the AT control loop and halts AT control (step  812 , section e), and the track jump circuit  517  applies a track jump pulse to the actuator  548 , causing the object lens  545  to move in a direction perpendicular to the information tracks  504  (step  813 , section e). 
     Thereupon, the track jump circuit  517  applies a brake pulse of opposite polarity to the track jump pulse to the actuator  548  (step  814 , section e), thereby decelerating the speed of movement of the object lens  545  such that it comes to rest in a position where the light beam spot shines onto the desired information track  504 . 
     When the illumination point of the light beam spot has moved to the desired information track  504 , the AF/AT control circuit  518  closes the AT control loop and starts AT control (step  815 , section e). 
     Next, when the relative speed of movement of the optical card  500  reaches the prescribed speed−v 1 , the MPU  512  applies a constant-speed pulse (voltage −V 2 ) for maintaining this speed to the x direction drive motor  516  (step  816 , section f), and the optical head  514  records or reproduces information to or from a desired track  504  of the optical card  500  (step  817 , section f). 
     When the optical card  500  and optical head  514  assume a prescribed positional relationship, the MPU  512  applies a decelerating pulse (voltage V 1 ) to the x direction drive motor  516 , thereby decelerating the relative speed of movement of the optical card  500  (step  818 , section g), and when the relative speed of movement of the optical card  500  reaches zero (YES at step  819 , section h), it returns to step  802  and applies an accelerating pulse to the x direction drive motor  516  (step  802 , section i). 
     These operations are repeated until the optical recording and reproduction device  510  has completed the prescribed recording and reproduction operations. 
     Furthermore, the track jump operation can be implemented during deceleration of the relative speed of movement, by a similar method. 
     In the first example of a conventional track jump operation described above, track jumping is implemented when the relative speed of movement between the optical card and optical head is constant. However, this constant state of the relative speed of movement corresponds to the timing at which the optical head scans the central region of the optical card, and since the optical card and optical head are moving at a high relative speed, the number of pits that can be formed in the central region of the optical card is reduced and consequently, a problem arises in that the amount of information that can be recorded onto the optical card is reduced. 
     Furthermore, in the second example of a conventional track jump operation, since track jumping is implemented when the relative speed of movement between the optical card and optical head is zero, in other words, when the optical head is scanning an end region of the optical card, the problem associated with the first example is resolved, but a further problem arises in that the relative speed of movement between the optical card and optical head must be held longer in a zero state in order to perform the track jump operation, and therefore the time required for recording or reproducing info is increased. 
     In the third example of a conventional track jump operation, since track jumping is implemented when the relative speed of movement between the optical card and the optical head is accelerating or decelerating, the optical head does not record or reproduce any information during this acceleration (or deceleration), and therefore there is no problem of reduced information recording capacity as in the first example, and it is also unnecessary to hold the relative speed of movement of the optical card and optical head at zero for a long period of time. 
     However, in the third example of a track Jump operation, due to the oscillation induced by acceleration or deceleration of the relative speed of movement between the optical card and optical head, a problem arises in that track jumping cannot be performed accurately and the device may jump incorrectly to a different information track from the desired information track. 
     SUMMARY OF THE INVENTION 
     Therefore, it is an object of the present invention to provide an optical information recording and reproduction device and method for same, whereby it is possible to prevent reduction in the information recording capacity of an optical card and increase in the recording and reproduction time associated with track jump operations, and incorrect track jumping caused by oscillations induced by acceleration or deceleration of the relative speed of movement between the optical card and optical head can be eliminated. 
     In order to achieve the aforementioned object, this invention provides an optical information recording and reproducing method for carrying out information recording and reproduction with respect to an optical information recording medium by means of an optical head, by moving the optical head relative to the optical information recording medium, comprising the steps of: providing a constant-speed region where the speed of the optical head is held constant in at least one of an acceleration region and a deceleration region of the optical head; and performing a jump operation to a recording and reproduction track by the optical head in the constant-speed region. 
     Here, the optical information recording medium may be constituted by an optical card. 
     Furthermore, the constant-speed region may be constituted by such that it corresponds to the time required for the jump operation. 
     Moreover, this invention provides an optical information recording and reproducing method for carrying out information recording and reproduction with respect to an optical card by means of an optical head, by moving the optical head relative to the optical card, comprising: 
     a first step of accelerating the optical card up to a prescribed speed with respect to the optical head; 
     a second step of moving the optical card at a first constant speed with respect to the optical head after the acceleration operation according to the first step has been completed; 
     a third step of decelerating the optical card from the prescribed speed; 
     a fourth step of moving the optical card at a second constant speed during at least one of the acceleration operation in the first step and the deceleration operation in the third step; 
     a fifth step of carrying out recording and reproduction of the information by means of the optical head during the first constant-speed operation in the second step; 
     and a sixth step of implementing a jump operation to a recording and reproduction track by the optical head during the second constant-speed operation according to the fourth step. 
     This invention also provides an optical information recording and reproduction device for carrying out information recording and reproduction with respect to an optical information recording medium by means of an optical head, by moving the optical head relative to the optical information recording medium, comprising: 
     movement speed control means for providing a constant-speed region where a speed of the optical head is held constant in at least one of an acceleration region and a deceleration region of the optical head; and track jump control means for implementing a jump operation to a recording and reproduction track by the optical head in the constant-speed region. 
     Here, the optical information recording medium may be constituted by an optical card. 
     Furthermore, the movement speed control means may be constituted such that the constant-speed region corresponds to a time period required for the jump operation. 
     Moreover, this invention provides an optical information recording recording and reproduction device for carrying out information recording and reproduction with respect to an optical card by means of an optical head, by reciprocally moving the optical card relative to the optical head, comprising: movement speed control means for controlling an acceleration operation in which the optical card is accelerated to a prescribed speed with respect to the optical head; a first constant-speed operation in which the optical card is moved at a prescribed constant speed, following the acceleration operation; a deceleration operation in which the optical card is decelerated from the prescribed speed, following the first constant-speed operation; and a second constant-speed operation in which the optical card is moved at a constant speed during at least one of the acceleration operation and the deceleration operation of the optical card; recording and reproducing means for carrying out recording and reproduction of the information by means of the optical head, during the first constant-speed operation; and track jump control means for implementing a jump operation to a recording and reproduction track by the optical head during the second constant-speed operation. 
     According to this invention, since a composition is adopted whereby regions are provided where the optical head and optical card are moved at a constant relative speed during the acceleration or deceleration of their relative speed of movement, when recording or reproducing information to or from an optical card, and track jump operations are performed in these regions, it is possible to prevent reduction in the information recording capacity of an optical card or increase in the recording and reproduction time due to these track jump operations, and furthermore, it is also possible to prevent track jump errors due to oscillations associated with the acceleration or deceleration of the relative speed of movement of the optical card and optical head. 
     Moreover, by avoiding the corner regions of the optical card and performing track jump operations towards the inner portion of the card, operational problems due to scratches or deformations, which are liable to occur in the corner regions of the optical card, can also be effectively prevented. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagram illustrating the relative speed of movement between an optical card and optical head in an optical information recording and reproducing method and device relating to this invention; 
     FIG. 2 is a diagram illustrating relative speed of movement and pulse voltages; 
     FIG. 3 is a flowchart showing the sequence of a track jump operation; 
     FIG. 4 is a diagram illustrating relative speed of movement and pulse voltages in a second embodiment; 
     FIG. 5 is a flowchart showing the sequence of a track jump operation in a second embodiment; 
     FIG. 6 is a diagram illustrating the composition of a general optical card; 
     FIG. 7 is an enlarged view of a recording region of the optical card; 
     FIG. 8 is a block diagram showing the composition of an optical information recording and reproduction device; 
     FIG. 9 is an approximate diagram showing the composition of an optical head; 
     FIG. 10 is a diagram illustrating the relationship between the relative speed of movement of an optical card and time, and their relationship to pulse voltages applied by the optical information recording and reproduction device to an actuator driving an optical card; 
     FIG. 11 is a flowchart showing the sequence of a track jump operation in an optical information recording and reproduction device according to a first conventional example; 
     FIG. 12 is a flowchart showing the sequence of a track jump operation in an optical information recording and reproduction device according to a second conventional example; and 
     FIG. 13 is a flowchart showing the sequence of a track jump operation in an optical information recording and reproduction device according to a third conventional example. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Below, one embodiment of an optical information recording and reproducing method and device relating to this invention is described in detail with reference to the accompanying drawings. 
     Since the optical card used in this embodiment is of similar composition to the conventional optical card  500  and the optical information recording and reproduction device is of similar composition to the conventional optical information recording and reproduction device  510 , these are described with reference to FIGS. 6-9. 
     FIG. 1 is a diagram illustrating an optical card and optical head in an optical information recording and reproducing method and device relating to this invention. 
     In FIG. 1, section a (a 1 , a 2 , a 3 ) is a section where the relative speed of movement between the optical card  500  and the optical head  514  is accelerated to a prescribed speed v 1  in order that the optical information recording and reproduction device  510  can record or reproduce information; section b is a section where the relative speed of movement between the optical card  500  and the optical head  514  is held constant (v 1 ) and information recording or reproduction is carried out; and section c (c 1 , c 2 , c 3 ) is a section where the relative speed of movement between the optical card  500  and optical head  514  is decelerated to zero. 
     Here, section a 2  is a section where the relative speed of movement between the optical card  500  and the optical head  514  is temporarily held at a constant speed (v 2 ) during the acceleration from zero to v 1 , and the optical information recording and reproduction device  510  performs a track jump operation in this section a 2 . 
     Similarly, section c 2  is a section where the relative speed of movement between the optical card  500  and the optical head  514  is temporarily held at a constant speed (v 2 ) during the deceleration from v 1  to zero, and the optical information recording recording and reproduction device  510  performs a track jump operation in this section c 2 . 
     Sections a 2  and c 2  can be set such that the speed is held constant at any position in the acceleration or deceleration periods of the relative speed of movement. 
     In practice, in order to record or reproduce information by reciprocal movement of the optical card  500 , the track jump operation can be carried out in either section a 2  during acceleration or section c 2  during deceleration. 
     Control for performing a track jump operation during acceleration or deceleration is performed by the CPU  511  or MPU  512 , which operate the various sections of the optical information recording and reproduction device  510  on the basis of processing commands recorded in a memory device (omitted from the drawings). 
     Here, a track jump operation will be described with reference to FIG.  2  and FIG.  3 . 
     FIG. 2 is a diagram illustrating relative speed of movement and pulse voltages, and FIG. 3 is a flowchart showing the sequence of a track jump operation. 
     When the optical information recording and reproduction device  510  starts reciprocal movement of the optical card  500  (step  101  in FIG.  3 ), firstly, the MPU  512  applies an accelerating pulse (voltage V 1 ) to the x direction drive motor  516 , thereby accelerating the optical card  500  to a prescribed speed v 2  (section al in FIG. 2, step  102 ), whereupon it applies a constant-speed pulse (voltage V 3 ) to the x direction drive motor  516  (section a 2 , step  103 ), and when the optical card  500  has reached a constant speed (section a 2 , YES at step  104 ), the AF/AT control circuit  518  opens the AT control loop (section a 2 , step  105 ), and the track jump circuit  517  applies a track jump pulse to an actuator  548  which drives the object lens  545  (section a 2 , step  106 ). 
     Next, the track jump circuit  517  applies a brake pulse to the actuator  548  such that the beam spot comes to rest over the desired information track  504  (section a 2 , step  107 ), the AF/AT control circuit  518  closes the AT control loop (section a 2 , step  108 ), and the MPU  512  again applies an accelerating pulse (voltage V 1 ) to the x direction drive motor  516 , causing the optical card  500  to accelerate to a prescribed speed v 1  (section a 3 , step  109 ). 
     When the relative speed of movement of the optical card  500  reaches the prescribed speed v 1 , the MPU  512  applies a constant-speed pulse (voltage V 2 ) to the x direction drive motor  516  (section b, step  110 ), and then the optical card  500  has assumed a constant speed (section b, YES at step  111 ), the optical head  514  records or reproduces information (section b, step  112 ). 
     When the beam spot reaches a prescribed position on the optical card  500  due to the movement of the optical card  500 , the MPU  512  applies a decelerating pulse (voltage −V 1 ) to the x direction drive motor  516  (section c, step  113 ), and when the relative speed of movement of the optical card  500  reaches zero (section d, YES at step  114 ), it switches the direction of movement of the optical card  500  (section d, step  115 ). 
     Thereupon, returning to step  102 , the MPU  512  applies an accelerating pulse (voltage −V 1 ) to the x direction drive motor  516 , thereby accelerating the optical card  500  to a prescribed speed−v 2  (section e 1 , step  102 ), whereupon it applies a constant-speed pulse (voltage −V 3 ) to the x direction drive motor  516  (section e 2 , step  103 ), and when the optical card  500  has assumed a constant speed (section e 2 , YES at step  104 ), the AF/AT control circuit  518  opens the AT control loop (section e 2 , step  105 ), and the track jump circuit  517  applies a track jump pulse to the actuator  548  (section e 2 , step  106 ). 
     Thereupon, the track jump circuit  517  applies a brake pulse to the actuator  548  such that the beam spot comes to rest over the desired information track  504  (section e 2 , step  107 ), the AF/AT control circuit  518  closes the AT control loop (section e 2 , step  108 ) and the MPU  512  again applies an accelerating pulse (voltage −V 1 ) to the x direction drive motor  516 , thereby accelerating the optical card  500  to a prescribed speed−v 1  (section e 3 , step  109 ). 
     When the relative speed of movement of the optical card  500  reaches the prescribed speed−v 1 , the MPU  512  applies a constant-speed pulse (voltage −V 2 ) to the x direction drive motor  516  (section f, step  110 ), and then the optical card  500  has assumed a constant speed (section f, YES at step  111 ), the optical head  514  records or reproduces information (section f, step  112 ). 
     When the beam spot reaches a prescribed position on the optical card  500  due to the movement of the optical card  500 , the MPU  512  applies a decelerating pulse (voltage V 1 ) to the xdirection drive motor  516  (section g, step  113 ), and when the relative speed of movement of the optical card  500  reaches zero (section h, YES at step  114 ), it switches the direction of movement of the optical card  500  (section h, step  115 ) and returns again to step  102 . 
     By means of the operation described above, the optical card  500  completes a single reciprocal movement cycle, and this movement is continued as necessary, to record or reproduce information. 
     Next, a second embodiment of a track jump operation is described with reference to FIGS.  4  and FIG.  5 . 
     FIG. 4 is a diagram illustrating the relative speed of movement and pulse voltages relating to the second embodiment, and FIG. 5 is a flowchart illustrating the sequence of a track jump operation in the second embodiment. 
     When the optical information recording and reproduction device  510  starts reciprocal movement of the optical card  500  (step  201  in FIG.  5 ), firstly, the MPU  512  applies an accelerating pulse (voltage V 1 ) to the x direction drive motor  516 , thereby accelerating the optical card  500  to a prescribed speed v 1  (section a in FIG. 4, step  202 ), whereupon the MPU  512  applies a constant-speed pulse (voltage V 2 ) to the x direction drive motor  516  (section b, step  203 ), and when the optical  500  has assumed a constant speed (section b, YES at step  204 ), the optical head  514  carries out information recording or reproduction (section b, step  205 ). 
     Furthermore, when the beam spot reaches a prescribed position on the optical card  500  due to the movement of the optical card  500 , the MPU  512  applies a decelerating pulse (voltage −V 1 ) to the x direction drive motor  516  (section c 1 , step  206 ), whereupon it applies a constant-speed pulse (voltage V 3 ) to the x direction drive motor  516  (section c 2 , step  207 ), and when the optical card  500  has assumed a constant speed (section c 2 , YES at step  208 ), the AF/AT control circuit  518  opens the AT control loop (section c 2 , step  209 ) and the track jump circuit  517  applies a track jump pulse to the actuator  548  driving the object lens  545  (section c 2 , step  210 ). 
     Thereupon, the track jump circuit  517  applies a brake pulse to the actuator  548  such that the beam spot comes to rest over the desired information track  504  (section c 2 , step  211 ), and the AF/AT control circuit  518  then closes the AT control loop (section c 2 , step  212 ), the MPU  512  applies a decelerating pulse (voltage −V 1 ) to the x direction drive motor  516 , thereby decelerating the relative speed of movement of the optical card  500  until it reaches zero (section c 3 , step  213 ), and when the relative speed of movement of the optical card  500  has reached zero (section d, YES at step  214 ), the direction of movement of the optical card  500  is switched (section d, step  215 ). 
     Returning to step  202 , the MPU  512  then applies an accelerating pulse (voltage −V 1 ) to the x direction drive motor  516 , thereby accelerating the optical card  500  to a prescribed speed−v 1  (section e, step  202 ), whereupon it applies a constant-speed pulse (voltage −V 2 ) to the x direction drive motor  516  (section f, step  203 ), and when the optical card  500  has reached a constant speed (section f, YES at step  204 ), the optical head  514  carries out information recording or reproduction (section f, step  205 ). 
     When the beam spot reaches a prescribed position on the optical card  500  due to the movement of the optical card  500 , the MPU  512  applies a decelerating pulse (voltage V 1 ) to the x direction drive motor  516  (section g 1 , step  206 ), whereupon it applies a constant-speed pulse (voltage −V 3 ) to the x direction drive motor  516  (section g 2 , step  207 ), and when the optical card  500  has assumed a constant speed (section g 2 , YES at step  208 ), the AF/AT control circuit  518  opens the AT control loop (section g 2 , step  209 ) and the track jump circuit  517  applies a track jump pulse to the actuator  548  driving the object lens  545  (section g 2 , step  210 ). 
     Thereupon, the track jump circuit  517  applies a brake pulse to the actuator  548  such that the beam spot comes to rest over the desired information track  504  (section g 2 , step  211 ), and the AF/AT control circuit  518  then closes the AT control loop (section g 2 , step  212 ), the MPU  512  again applies a decelerating pulse (voltage V 1 ) to the x direction drive motor  516 , thereby decelerating the relative speed of movement of the optical card  500  until it reaches zero (section g 3 , step  213 ). 
     When the relative speed of movement of the optical card  500  has reached zero (section h, YES at step  214 ), the direction of movement of the optical card  500  is switched (section h, step  215 ), and the process returns to step  102 . 
     By means of the operation described above, the optical card  500  completes a single reciprocal movement cycle, and this movement is continued as necessary, to record or reproduce information. 
     The time periods of sections a 2 , e 2  in the first embodiment and sections c 2 , g 2  in the second embodiment may be set to different times, for example, in cases where the device is jumping to an adjacent information track and cases where it is jumping to an information track several tracks apart, in response to the different times required for track jumping, or they may be set to fixed time periods. 
     Moreover, sections for implementing the track jump operation may be provided both in the acceleration region (a, e) and in the deceleration region (c, g), and track jumping may be performed in a step fashion in cases where the device is jumping to an information track several tracks apart.