Abstract:
A haptic sense rendering apparatus is disclosed that includes a haptic sense rendering unit, a magnet, a coil that magnetically interacts with the magnet and drives the haptic sense rendering unit, and a drive circuit that generates a drive signal for driving the haptic sense rendering unit to emphasize at least one of a drive starting operation and a drive terminating operation and supplies the generated drive signal to the coil.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a haptic sense rendering apparatus that renders haptic information through movement of a haptic sense rendering unit and a method of driving such a haptic sense rendering apparatus. 
         [0003]    2. Description of the Related Art 
         [0004]    In recent years and continuing, haptic sense rendering apparatuses are being developed for use in operations control devices such as an input unit of a computer, an operations unit of an audio apparatus, and an operations unit of a car navigation system that is installed in a vehicle. Such haptic sense rendering apparatuses are designed to convey information to an operator by rendering a haptic sensation via a haptic sense rendering unit so that the operator may feel a force at his/her fingertips upon touching the haptic sense rendering unit with his/her fingertips. 
         [0005]    A flat mobile haptic sense rendering apparatus may have four magnets arranged flat on a plane and drive coils arranged above and parallel to these four magnets, and a thrust may be generated by supplying electric currents through these drive coils, for example. That is, by arranging plural drive coils to face plural magnets that are arranged flat on a plane and controlling the electric current being supplied to these drive coils, a desired force may be generated by the drive coils to thereby cause relative movement of a haptic sense rendering unit. It is noted that Japanese Patent Laid-Open Patent Publications No. 2000-330688 and No. 2004-145748 disclose examples of flat mobile haptic sense rendering apparatuses that implement such a configuration. 
         [0006]    In the case of using such a haptic sense rendering apparatus in an input device of a computer or an operations unit of a vehicle, it is desired that the apparatus be miniaturized and the thrust generated by the drive coils be increased. 
         [0007]    However, in order to increase the thrust to be rendered by the haptic sense rendering apparatus as is described above, the magnetic fields of the magnets have to be increased or the electric currents supplied to the drive coils have to be increased. To increase the magnetic fields of the magnets, suitable materials may have to be selected or the volume of the magnets has to be increased. It is noted that selecting suitable materials for the magnets may lead to cost increase. Also, in the case of increasing the volume of the magnets, miniaturization of the apparatus may be hampered. 
         [0008]    Thus, in order to increase the thrust generated by the drive coils, the electric current supplied to the drive coils has to be increased. However, increasing the electric current supplied to the drive coils may lead to an increase in heat generation. This may be a problem since heat dissipation performance is degraded when the apparatus is miniaturized and heat generation per unit volume may be increased as a result. 
         [0009]    Accordingly, there is a demand for a haptic sense rendering apparatus that is small in size and is capable of rendering a strong thrust without causing an increase in heat generation. 
       SUMMARY OF THE INVENTION 
       [0010]    Aspects of the present invention are directed to providing a haptic sense rendering apparatus that is small in size and is capable of rendering a strong sense of thrust without causing an increase in heat generation and a method of driving such a haptic sense rendering apparatus. 
         [0011]    According to one embodiment of the present invention, a haptic sense rendering apparatus is provided that includes a haptic sense rendering unit, a magnet, a coil that magnetically interacts with the magnet and drives the haptic sense rendering unit, and a drive circuit that generates a drive signal for driving the haptic sense rendering unit to emphasize a drive starting operation or a drive terminating operation and supplies the generated drive signal to the coil. 
         [0012]    According to another embodiment of the present invention, a method of driving a haptic sense rendering apparatus that includes a haptic sense rendering unit, a magnet, and a coil that magnetically interacts with the magnet and drives the haptic sense rendering unit, the method comprising the steps of generating a drive signal for driving the haptic sense rendering unit to emphasize a drive starting operation or a drive terminating operation, and supplying the generated drive signal to the coil. 
         [0013]    In one preferred embodiment, the drive signal may be arranged to have an amplitude that is greater than a basic amplitude of the drive signal upon driving the haptic sense rendering unit to perform the drive start operation or the drive terminating operation. 
         [0014]    In another preferred embodiment, the drive signal may include a basic pulse and an auxiliary pulse that is attached to an edge portion of the basic pulse. 
         [0015]    In another preferred embodiment, the auxiliary pulse may be attached to the rising edge portion of the basic pulse, have the same polarity as the basic pulse, and have an amplitude that is greater than the amplitude of the basic pulse. 
         [0016]    In another preferred embodiment, the auxiliary pulse may be attached to the falling edge portion of the basic pulse and have an opposite polarity with respect to the polarity of the basic pulse. 
         [0017]    In another preferred embodiment, the auxiliary pulse may be attached to the rising edge portion of the basic pulse and have an opposite polarity with respect to the polarity of the basic pulse. 
         [0018]    In another preferred embodiment, the auxiliary pulse may include a first auxiliary pulse having an amplitude that is greater than the amplitude of the basic pulse and a second auxiliary pulse having an amplitude that is less than the amplitude of the basic pulse. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a perspective view of a haptic sense rendering apparatus according to an embodiment of the present invention; 
           [0020]      FIG. 2  is a exploded perspective view of a part of the haptic sense rendering apparatus shown in  FIG. 1 ; 
           [0021]      FIG. 3  is a circuit diagram of the haptic sense rendering apparatus shown in  FIG. 1 ; 
           [0022]      FIG. 4  is a diagram illustrating operations of the haptic sense rendering apparatus shown in  FIG. 1 ; 
           [0023]      FIG. 5  is a flowchart illustrating process operations performed in response to receiving a thrust command signal; 
           [0024]      FIG. 6  is a diagram showing an exemplary waveform of a drive signal that may be used in an embodiment of the present invention; 
           [0025]      FIGS. 7A and 7B  are tables showing haptic test results of using differing drive pulses; 
           [0026]      FIGS. 8A and 8B  are tables showing haptic test results of using another set of differing drive pulses; 
           [0027]      FIG. 9A  is a diagram showing a current waveform of a drive signal including only a basic pulse, and  FIG. 9B  is a diagram showing a thrust waveform obtained by the drive signal of  FIG. 9A ; 
           [0028]      FIG. 10A  is a diagram showing a current waveform of a drive signal including a basic pulse and an auxiliary pulse of 100 msec, and  FIG. 10B  is a diagram showing a thrust waveform obtained by the drive signal of  FIG. 10A ; 
           [0029]      FIG. 11A  is a diagram showing a current waveform of a drive signal including a basic pulse and an auxiliary pulse of 80 msec, and  FIG. 11B  is a diagram showing a thrust waveform obtained by the drive signal of  FIG. 11A ; 
           [0030]      FIG. 12A  is a diagram showing a current waveform of a drive signal including a basic pulse and an auxiliary pulse of 60 msec, and  FIG. 12B  is a diagram showing a thrust waveform obtained by the drive signal of  FIG. 12A ; 
           [0031]      FIG. 13A  is a diagram showing a current waveform of a drive signal including a basic pulse and an auxiliary pulse of 40 msec, and  FIG. 13B  is a diagram showing a thrust waveform obtained by the drive signal of  FIG. 13A ; 
           [0032]      FIG. 14A  is a diagram showing a current waveform of a drive signal including a basic pulse and an auxiliary pulse of 20 msec, and  FIG. 14B  is a diagram showing a thrust waveform obtained by the drive signal of  FIG. 14A ; 
           [0033]      FIG. 15A  is a diagram showing a current waveform of a drive signal including a basic pulse and an auxiliary pulse of 10 msec, and  FIG. 15B  is a diagram showing a thrust waveform obtained by the drive signal of  FIG. 15A ; 
           [0034]      FIG. 16  is a diagram showing a waveform of a drive signal according to a first modified embodiment; and 
           [0035]      FIG. 17  is a diagram showing a waveform of a drive signal according to a second modified embodiment. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0036]    In the following, preferred embodiments of the present invention are described with reference to the accompanying drawings. 
         [0037]      FIG. 1  is a perspective view of a haptic sense rendering apparatus according to a first embodiment of the present invention;  FIG. 2  is an exploded perspective view of a part of the haptic sense rendering apparatus according to the first embodiment;  FIG. 3  is a circuit diagram of the haptic sense rendering apparatus according to the first embodiment; and  FIG. 4  is a diagram illustrating operations of the haptic sense rendering apparatus according to the first embodiment. 
         [0038]    The illustrated haptic sense rendering apparatus  100  according to the first embodiment corresponds to the so-called haptic actuator. The haptic sense rendering apparatus  100  is configured to drive a haptic sense rendering unit  112  on an X-Y plane corresponding to an operations plane based on a drive signal from a control unit  116 . 
         [0039]    The haptic sense rendering apparatus  100  includes a stationary part  111  that is made up of a frame  121  that fixes magnets  122   a,    122   b,    122   c,  and  122   d  in place on an X-Y plane in a ring-shaped arrangement. The magnets  122   a,    122   b,    122   c,  and  122   d  are plate-shaped magnets that have magnetic poles aligned in the Z directions perpendicular to the X-Y plane, and are arranged such that adjacent magnets have opposite magnetic polarities with respect to each other. 
         [0040]    The haptic sense rendering unit  112  includes a circuit substrate  131  having a hole IC  132 , coils  133   a,    133   b,    133   c,    133   d,  and a controller  134  mounted thereon. The haptic sense rendering apparatus  112  is configured to move on the X-Y plane relative to the stationary part  11 . Also, the haptic sense rendering unit  112  has a haptic unit  130  mounted thereon, and the haptic sense rendering unit  112  is configured to move according to the movement of this haptic unit  130 . 
         [0041]    The hole IC  132  includes four hole elements  132   a,    132   b,    132   c,  and  132   d  that are connected to the controller  134 . 
         [0042]    The controller  134  includes amplifiers  141   a,    141   b,  an MCU (micro controller unit)  142 , a driver  143 , and a storage unit  144 . The amplifier  141   a  outputs the difference between outputs of the hole element  132   a  and the hole element  132   c.  The hole elements  132   a  and  132   c  may be arranged along the X axis directions, for example. In this case, the amplifier  141   a  may output a signal according to the position of the haptic sense rendering unit  112  along the X axis directions relative to the position of the stationary part  111 . 
         [0043]    The amplifier  141   b  outputs the difference between outputs of the hole element  132   b  and the hole element  132   d.  The hole elements  132   b  and  132   d  may be arranged along the Y axis directions, for example. In this case, the amplifier  141   b  may output a signal according to the position of the haptic sense rendering unit  112  along the Y axis directions relative to the position of the stationary unit  111 . 
         [0044]    The outputs of the amplifiers  141   a  and  141   b  are input to the MCU  142 . The MCU  142  creates position information of the haptic sense rendering unit  112  with respect to the stationary part  111  based on the outputs of the amplifiers  141   a  and  141   b  and inputs the position information to the control unit  116 . 
         [0045]    Also, the MCU  142  executes processes based on programs installed in the storage unit  144 . For example, the MCU  142  may execute a process of generating a drive signal based on a drive command signal input thereto from the control unit  116  and inputting the generated drive signal to the driver  143 . In this case, the MCU  142  may generate the drive signal based on auxiliary pulse waveform data stored in the storage unit  144 . 
         [0046]    It is noted that the drive signal may be an analog waveform signal or a digital waveform signal such as a PWM (pulse width modulated) signal. 
         [0047]    The driver  143  may be a current amplifying circuit, a power amplifier, or an H bridge driver circuit, for example, and is configured to input a drive current to the coils  133   a,    133   b,    133   c,  and  133   d  based on the drive signal from the MCU  142 . The coils  133   a,    133   b,    133   c,  and  133   d  are arranged to face the magnets  122   a,    122   b,    122   c,  and  122   d.  Specifically, the coil  133   a  is arranged between the magnets  122   a  and  122   b,  the coil  133   b  is arranged between the magnets  122   b  and  122   c,  the coil  133   c  is arranged between the magnets  122   c  and  122   d,  and the coil  133   d  is arranged between the magnets  122   d  and  122   a.  With such an arrangement, the magnets  122   a,    122   b,    122   c,    122   d,  and the coils  133   a,    133   b,    133   c,  and  133   d  may make up a voice coil motor that is driven on the X-Y plane. 
         [0048]    In this way, the haptic sense rendering unit  112  may move along the X-Y plane when drive currents are supplied to the coils  133   a,    133   b,    133   c,  and  133   d.    
         [0049]      FIG. 5  is a flowchart illustrating operations of the MCU  142  upon receiving a thrust command signal. 
         [0050]    Upon receiving a thrust command signal from a superordinate apparatus (step S 1 - 1 ), the MCU  142  interprets the received thrust command signal and selects an auxiliary pulse waveform according to the received thrust command signal (step S 1 - 2 ). 
         [0051]    Then, the MCU  142  creates an auxiliary pulse according to the thrust command signal using a basic pulse obtained by the thrust command signal (step S 1 - 3 ). For example, the MCU  142  may create an auxiliary pulse having an amplitude that is approximately 1.5 times the amplitude of the basic pulse (step S 1 - 3 ). 
         [0052]    Then, the MCU  142  outputs the auxiliary pulse to the coils  133   a,    133   b,    133   c,  and  133   d  via the driver  143  (step S 1 - 4 ). The MCU  142  then monitors the time to determine whether 20 msec has elapsed after outputting the auxiliary pulse (step S 1 - 5 ). After 20 msec has elapsed after outputting the auxiliary pulse, the MCU  142  outputs the basic pulse in place of the auxiliary pulse (step S 1 - 6 ). 
         [0053]    Then, the MCU  142  monitors whether an off command signal is received from a superordinate apparatus (step S 1 - 7 ). Upon receiving an off command signal from the superordinate apparatus (step S 1 - 7 , YES), the MCU  142  interprets the received off command signal and selects an auxiliary pulse waveform of an off pulse for terminating the process (step S 1 - 8 ). 
         [0054]    Then, the MCU  142  creates an auxiliary pulse according to the off command using the basic pulse (step S 1 - 9 ), and outputs the auxiliary pulse (step S 1 - 10 ). After completing the operations of outputting the auxiliary pulse (step S 1 - 11 ), the present process may be terminated. 
         [0055]    It is noted that the drive signal obtained in the above-described process may be distributed to the coils  133   a,    133   b,    133   c,  and  133   d  according to the direction of the thrust, for example. Alternatively, a drive signal made up of a basic pulse and an auxiliary pulse may be individually created for each of the coils  133   a,    133   b,    133   c,  and  133   d  according to the direction of the thrust. 
         [0056]    In the following, the waveform of the drive signal obtained in the above-described process is described. 
         [0057]      FIG. 6  is a diagram illustrating an exemplary waveform of the drive signal obtained by the above-described process. 
         [0058]    When the MCU  142  receives a thrust command signal, an auxiliary pulse pa 1  is output from the driver  143  to at least one of the coils  133   a,    133   b,    133   c,  and  133   d  that is to be driven. In the illustrated example of  FIG. 6 , the auxiliary pulse pa 1  is output for 20 msec after which a basic pulse pb is output. Then, when the MCU  142  receives an off command signal, another auxiliary pulse pa 2  is output for 20 msec. 
         [0059]      FIGS. 7A-15B  are diagrams showing haptic test results of using various drive signals that include auxiliary pulses and basic pulses. 
         [0060]      FIGS. 7A and 7B  are tables indicating haptic comparison test results obtained by comparing a case of using a drive pulse including a basic pulse pb and an auxiliary pulse pa 1  with a case of using a drive signal that only includes the basic pulse pb, where a thrust indicating value of the basic pulse pb is set to 128 (indicating a thrust of approximately 0.4 N), the output duration (pulse width) of the basic pulse pb is set to 300 msec, and the thrust indicating value and the output duration (pulse width) of the auxiliary pulse are arranged to vary.  FIGS. 8A and 8B  are tables indicating haptic comparison test results obtained by comparing a case of using a drive pulse including a basic pulse pb and an auxiliary pulse pa 1  with a case of using a drive signal that only includes the basic pulse pb, where a thrust indicating value of the basic pulse pb is set to 128 (indicating a thrust of approximately 0.4 N), the output duration (pulse width) of the basic pulse pb is set to 500 msec, and the thrust indicating value and the output duration (pulse width) of the auxiliary pulse are arranged to vary. It is noted that  FIGS. 7A and 8A  show the haptic comparison test results obtained from subject A, and  FIGS. 7B and 8B  show the haptic comparison test results obtained from subject B. Also, in these tables, a circle ◯ indicates that a difference was recognized between the case of using the drive pulse including both the auxiliary pulse pa 1  and the basic pulse pb and the case of using the drive pulse only including the basic pulse pb, and a cross X indicates that such a difference was not recognized between the two cases. 
         [0061]    As can be appreciated,  FIGS. 7A ,  7 B,  8 A, and  8 B show comparison results obtained by varying the thrust indicating value of the auxiliary pulse pa 1  to take five different values, 64, 48, 32, 24, and 16. 
         [0062]    It is noted that the thrust indicating value of the auxiliary pulse pa 1  represents a value to be added to the thrust indicating value 128 of the basic pulse pb. For example, when the thrust indicating value of the auxiliary pulse pa 1  is set to 64, a thrust corresponding to the sum of this value 64 and the thrust indicating value 128 of the basic pulse pb (128+64)=192 is designated; that is, a thrust of approximately 0.6 N corresponding to the sum (128+64)=192 is designated by the thrust indicating value 64 of the auxiliary pulse pa 1 . Similarly, when the thrust indicating value of the auxiliary pulse pa 1  is set to 16, a thrust of approximately 0.45 N corresponding to the sum of this value 16 and the thrust indicating value 128 of the basic pulse pb (128+16)=144 is designated. 
         [0063]      FIG. 9A  is a diagram showing a current waveform of a drive signal that only includes a basic pulse, and  FIG. 9B  is a diagram showing a thrust waveform obtained by the drive signal of  FIG. 9A . 
         [0064]      FIG. 10A  is a diagram showing a current waveform of a drive signal that includes a basic pulse and an auxiliary pulse having a duration (pulse width) of 100 msec, and  FIG. 10B  is a diagram showing a thrust waveform obtained by the drive signal of  FIG. 10A .  FIG. 11A  is a diagram showing a current waveform of a drive signal that includes a basic pulse and an auxiliary pulse having a duration of 80 msec, and  FIG. 11B  is a diagram showing a thrust waveform obtained by the drive signal of  FIG. 11A .  FIG. 12A  is a diagram showing a current waveform of a drive signal that includes a basic pulse and an auxiliary pulse having a duration of 60 msec, and  FIG. 12B  is a diagram showing a thrust waveform obtained by the drive signal of  FIG. 12A .  FIG. 13A  is a diagram showing a current waveform of a drive signal that includes a basic pulse and an auxiliary pulse having a duration of 40 msec, and  FIG. 13B  is a diagram showing a thrust waveform obtained by the drive signal of  FIG. 13A .  FIG. 14A  is a diagram showing a current waveform of a drive signal that includes a basic pulse and an auxiliary pulse having a duration of 20 msec, and  FIG. 14B  is a diagram showing a thrust waveform obtained by the drive signal of  FIG. 14A .  FIG. 15A  is a diagram showing a current waveform of a drive signal that includes a basic pulse and an auxiliary pulse having a duration of 10 msec, and  FIG. 15B  is a diagram showing a thrust waveform obtained by the drive signal of  FIG. 15A . 
         [0065]    As can be appreciated from  FIGS. 7A-8B , a difference may be recognized between the case of using a drive pulse only including a basic pulse and the case of using a drive pulse including an auxiliary pulse and a basic pulse provided that the thrust indicating value of the auxiliary pulse pa 1  is at least 32, namely, the thrust designated by the auxiliary pulse pa 1  (thrust of approximately 0.5 N corresponding to the sum 128+32=160) is at least 125% of the thrust designated by the basic pulse pb (thrust of 0.4 N corresponding to the thrust indicating value 128), and the duration of the auxiliary pulse pa 1  is at least 20 msec. 
         [0066]    As can be appreciated from  FIGS. 9B-15B , overshoot and oscillation occur at the rise time and fall time of the thrust waveforms. When the duration of the auxiliary pulse is too short (e.g., approximately 10 msec as in  FIG. 15B ), effects of the auxiliary pulse pa 1  may be buried by the overshoot and oscillation. Specifically, the thrust to be rendered by a drive signal that only includes a basic pulse may not be adequately strengthened by using a drive pulse that includes an auxiliary pulse and a basic pulse in the case where the duration of the auxiliary pulse pa 1  is too short. 
         [0067]    Also, as can be appreciated from  FIGS. 7A-8B , when the thrust indicating value of the auxiliary pulse pa 1  is set to 16 so that a thrust of approximately 0.45 N corresponding to the value (128+16)=144, which is approximately 112.5% of the thrust of the basic pulse pb, is designated by the auxiliary pulse pa 1 , a difference cannot be recognized between the case of using a drive pulse that only includes the basic pulse pb and the case of using a drive pulse that includes the auxiliary pulse pa 1  and the basic pulse pb even when the duration of the auxiliary pulse pb is arranged to be relatively long (e.g., approximately 100 msec). When the thrust indicating value of the auxiliary pulse pa 1  is set to 24 so that a thrust of approximately 0.475 N corresponding to the value (128+24)=152, which is approximately 119% of the thrust of the basic pulse pb, is designated by the auxiliary pulse pa 1 , a difference between the case of using a drive pulse that only includes the basic pulse pb and the case of using a drive pulse that includes the auxiliary pulse pa 1  and the basic pulse pb may or may not be recognized depending on other various factors. 
         [0068]    As can be appreciated from the above descriptions, effects of the auxiliary pulse pa 1  may be recognized when the auxiliary pulse pa 1  is arranged to adequately enhance the thrust to be rendered by a drive signal, for example. In one preferred embodiment, the thrust indicated by the thrust indicating value of the auxiliary pulse pa 1  may be set to at least 125% of the thrust indicated by the thrust indicating value of the basic pulse pb. In another preferred embodiment, the duration of the auxiliary pulse may be set to at least 20 msec. 
         [0069]    Also, as is shown in  FIG. 6 , the drive signal may have another auxiliary pulse pa 2  inserted at the fall of the basic pulse pb for enabling easy recognition of the end of the thrust applying process. 
         [0070]    It is noted that in the above-described embodiment, the auxiliary pulse pa 1  corresponds to an orthogonal wave. However, the present invention is not limited to such an embodiment and other types of waveforms may be used as the auxiliary pulse pa 1  as well. 
         [0071]      FIG. 16  is a diagram showing a waveform of a drive signal according to a first modified embodiment. 
         [0072]    The drive signal according to the first modified embodiment includes an auxiliary pulse pa 11  having a different waveform from that of the auxiliary pulse pa 1  of the drive signal shown in  FIG. 6 . 
         [0073]    The auxiliary pulse pa 11  of the present modified embodiment has an opposite polarity with respect to that of the basic pulse pb, an amplitude that is at least 25% of the amplitude of the basic pulse pb, and a pulse width (duration) of 20 msec, for example. 
         [0074]    By attaching the auxiliary pulse pa 11  to the basic pulse pb as in the present modified embodiment, a thrust in an opposite direction with respect to the direction of the trust to be generated by the basic pulse may be applied before the thrust generated by the basic pulse pb is applied. In this way, the change in thrust from that rendered by the auxiliary pulse pa 11  to that rendered by the basic pulse pb may be perceived as a thrust that is greater than the thrust corresponding to the amplitude of the basic pulse pb so that the thrust generated by the basic pulse pb may be perceived as being enhanced by using the drive signal of the present modified embodiment. 
         [0075]      FIG. 17  is a diagram showing a waveform of a drive signal according to a second modified embodiment. 
         [0076]    The drive signal according to the second modified embodiment includes an auxiliary pulse pa 21  that is different from the auxiliary pulse pa 1  of the drive signal shown in  FIG. 6  and the auxiliary pulse pa 11  of the drive signal shown in  FIG. 16 . 
         [0077]    The auxiliary pulse pa 21  of the present modified embodiment is made up of a first auxiliary pulse pa 31  and a second auxiliary pulse pa 32 . The first auxiliary pulse pa 31  has a same polarity as that of the basic pulse pb, an amplitude that is at least 125% of the amplitude of the basic pulse pb, and a pulse width (duration) of approximately 10 msec. The second auxiliary pulse pa 32  is output after the first auxiliary pulse pa 31  and has an amplitude that is approximately 75% of the amplitude of the basic pulse pb and a pulse width (duration) of approximately 10 msec. 
         [0078]    By attaching the auxiliary pulse pa 21  to the basic pulse pb as in the present modified embodiment, a thrust that is greater than the thrust to be generated by the basic pulse pb is generated by the first auxiliary pulse pa 31  after which a thrust that is less than the thrust to be generated by the basic pulse pb is generated by the second auxiliary pulse pa 32 . Then, the thrust generated by the basic pulse may be applied. In this way, the thrust generated by the basic pulse pb may be perceived as being enhanced by using the drive signal according to the present modified embodiment. 
         [0079]    As can be appreciated from the above-descriptions, according to certain aspects of the present invention, by generating a drive signal for driving a haptic sense rendering unit to emphasize a drive starting operation or a drive terminating operation, and supplying the generated drive signal to a coil that drives the haptic sense rendering unit, the drive starting operation or the drive terminating operation of the haptic sense rendering unit may be clearly indicated so that the thrust rendered by the haptic sense rendering unit may be perceived as being stronger than the actual thrust acting on the haptic sense rendering unit. In this way, a strong thrust may be felt by merely increasing the current supplied to the coil by a slight amount upon performing the drive staring operation or the drive terminating operation, for example. In turn, a haptic sense rendering apparatus that is small in size and is capable of rendering a strong sense of thrust without increasing heat generation may be realized. 
         [0080]    It is noted that the haptic sense rendering apparatus  100  as described above is configured to generate an auxiliary pulse that is to be attached to a basic pulse upon receiving a command signal from a superordinate apparatus and input the generated auxiliary pulse to at least one of the coils  133   a,    133   b,    133   c,  and  133   d.  However, the present invention is not limited to such an embodiment and in another embodiment, a pulse waveform including a basic pulse and an auxiliary pulse may be generated at the superordinate apparatus and input to the haptic sense rendering apparatus  100  so that the haptic sense rendering apparatus  100  may be driven by the pulse waveform supplied by the superordinate apparatus. 
         [0081]    Also, it is noted that although the auxiliary pulse is attached to the rising edge of the basic pulse of a current waveform in the above-described embodiments, the present invention is not limited to such embodiments and the auxiliary pulse may alternatively be attached to the rising edge of a thrust waveform to be output, for example. 
         [0082]    Also, it is noted that although the haptic sense rendering apparatus  100  as described above corresponds to a two-dimensional haptic sense rendering apparatus, the present invention may similarly be embodied in a one-dimensional haptic sense rendering apparatus or a three-dimensional haptic sense rendering apparatus, for example. 
         [0083]    Further, the present invention is not limited to these embodiments, and variations and modifications may be made without departing from the scope of the present invention. 
         [0084]    The present application is based on and claims the benefit of the earlier filing date of Japanese Patent Application No. 2007-177473 filed on Jul. 5, 2007, the entire contents of which are hereby incorporated by reference.