Abstract:
A touch panel assembly includes a touch-sensitive panel oriented along a plane. An actuator includes a frame having a first portion and a second portion at least partially oriented parallel to the plane. The first portion and the second portion are coupled together with a biasing element. A first magnetic device is coupled to the first portion. A second magnetic device is coupled to the second portion and positioned adjacent to the first magnetic device. The first magnetic device configured to move the first portion in a first direction parallel to the plane when energized by a current to cause a haptic effect to be felt on the touch sensitive panel. The biasing element applies a biasing force which causes the first portion to move in a second direction opposite to the first direction.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of co-pending U.S. patent application Ser. No. 11/128,717 filed May 12, 2005, in the name of inventors George V. Anastas and Neil T. Olien and entitled “Method And Apparatus For Providing Haptic Effects To A Touch Pane,l” commonly owned herewith. 
     
    
     GOVERNMENT INTEREST 
       [0002]    This invention was made with support under grant number DMI-0441692 from the National Science Foundation. The United States Government has certain rights in the invention. 
     
    
     TECHNICAL FIELD 
       [0003]    The present invention relates to the field of computer interface systems. More particularly, the present invention relates to a user interface device that provides haptic effect in response to user inputs. 
       BACKGROUND 
       [0004]    As computer-based systems, appliances, automated teller machines (ATM), point-of-sale terminals and the like become more prevalent, the ease of use of the human-machine interface is becoming more and more important. Such interfaces should operate intuitively and with little or no training so that they may be employed by virtually anyone. Many conventional user interface devices are available on the market and include the keyboard, the mouse, the joystick, the touch screen, and the touchpad. One of the most intuitive and interactive interface devices known is the touch panel, which is also known as a touch screen, a touch pad, a touch screen display, and so forth. A touch panel includes a touch-sensitive input panel and a display device, usually in a sandwich structure and provides a user with a machine interface through touching a panel sensitive to the user&#39;s touch and displaying content that the user “touches.” 
         [0005]    A touch panel can be a small planar rectangular pad, which can be installed in or near a computer, an automobile, ATM machines, and the like. A conventional touch-sensitive component of a touch panel employs various types of touch sensing technology such as capacitive sensing, pressure sensing and the like as known in the art to detect locations being pressed on the panel. For example, a user contacts the touch-sensitive panel commonly with a fingertip to emulate a button press and/or moves his or her finger on the panel according to the graphics displayed behind the panel on the display device. 
         [0006]    A problem associated with conventional touch panels is that they lack the capability of providing interactive tactile acknowledgements to indicate whether input has been accepted or rejected. 
         [0007]    Accordingly, there is a need for a touch panel to provide an interactive tactile feedback to indicate whether a user&#39;s selection has been accepted or rejected and/or other appropriate or desirable effects. 
       SUMMARY 
       [0008]    In an aspect, a touch panel assembly includes a touch-sensitive panel oriented along a plane. An actuator includes a frame having a first portion and a second portion at least partially oriented parallel to the plane. The first portion and the second portion are coupled together with a biasing element. A first magnetic device is coupled to the first portion. A second magnetic device is coupled to the second portion and positioned adjacent to the first magnetic device. The first magnetic device configured to move the first portion in a first direction parallel to the plane when energized by a current to cause a haptic effect to be felt on the touch sensitive panel. The biasing element applies a biasing force which causes the first portion to move in a second direction opposite to the first direction. 
         [0009]    In an aspect, a method for providing haptic effects in a touch panel assembly, the method comprises measuring a touching contact with a touch-sensitive panel, wherein the touch-sensitive panel is oriented along a plane; generating a first signal in response to the touching contact; transmitting the first signal to a processor; generating a haptic output current signal in response to said first signal, wherein the haptic output current signal is transmitted to an actuator having a first portion coupled to the touch-sensitive panel and a second portion arranged to adjacent to the first portion, wherein the first portion and the second portion are oriented parallel to the plane, the actuator having a first magnetic device coupled to the first portion and a second magnetic device coupled to the second portion, wherein the haptic output current signal causes the first magnetic device and first portion to move in a first direction parallel to the plane to cause a haptic effect to be felt at the touch-sensitive panel, the actuator including a biasing element coupled to the first and second portions configured to apply a biasing force which causes the first portion to move in a second direction opposite to the first direction. Additional features and benefits of the present invention will become apparent from the detailed description, figures and claims set forth below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The accompanying drawings, which are incorporated into and constitute as part of this specification, illustrate one or more embodiments of the present invention and, together with the detailed description, serve to explain the principles and implementations of the invention. 
           [0011]    In the drawings: 
           [0012]      FIG. 1  is an elevational diagram illustrating an actuator for providing haptic effects in accordance with one embodiment of the present invention; 
           [0013]      FIG. 2  is an elevational diagram illustrating alternative electromagnetic components for generating attractive magnetic force in an actuator in accordance with one embodiment of the present invention; 
           [0014]      FIG. 3  is an elevational diagram of an alternative embodiment of an actuator in accordance with the present invention; 
           [0015]      FIG. 4  is an elevational diagram of another embodiment of an actuator in accordance with the present invention; 
           [0016]      FIG. 5  is an elevational diagram of a system employing an actuator in accordance with one embodiment of the present invention; 
           [0017]      FIG. 6  is an elevational diagram illustrating a second equilibrium position of an actuator in accordance with one embodiment of the present invention; 
           [0018]      FIG. 7  is a front respective diagram of a system configured with a plurality of actuators in accordance with one embodiment of the present invention; 
           [0019]      FIG. 8  is a flow diagram illustrating a method for generating haptic effects in accordance with one embodiment of the present invention; and 
           [0020]      FIG. 9  is a block diagram illustrating a system having an actuator in accordance with one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    Embodiments of the present invention are described herein in the context of a method and apparatus for providing haptic effects to a touch panel. Those of ordinary skill in the art will realize that the following detailed description of the present invention is illustrative only and is not intended to be in any way limiting. Other embodiments of the present invention will readily suggest themselves to such skilled persons having the benefit of this disclosure. Reference will now be made in detail to implementations of the present invention as illustrated in the accompanying drawings. The same reference indicators will be used throughout the drawings and the following detailed description to refer to the same or like parts. 
         [0022]    In the interest of clarity, not all of the routine features of the implementations described herein are shown and described. It will, of course, be appreciated that in the development of any such actual implementation, numerous implementation-specific decisions must be made in order to achieve the developer&#39;s specific goals, such as compliance with application- and business-related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure. 
         [0023]    The present invention relates to a user interface system that, in one embodiment, includes a display, an actuator and a touch-sensitive panel. A housing, such as a case, carrier, base, frame or the like may also be used to house the display, actuator and touch-sensitive panel. The actuator includes at least a pair of magnetic devices and at least one biasing element arranged to counter the gap-closing attractive force of the magnetic devices for providing haptic effects. 
         [0024]    Turning now to the figures,  FIG. 1  illustrates an actuator  100  for generating haptic effects in accordance with one embodiment of the present invention. Actuator  100  includes two L-shaped pole pieces  110 ,  112 , first and second structural elements  102  and  104  and first and second biasing elements  106  and  108 . Pole pieces  110 ,  112 , may be made of standard magnetic steels with high permeability, or other suitable ferromagnetic materials such as soft magnetic materials with high magnetic permeability (e.g., iron, nickel, magnetic alloys) or sintered materials such as ferrite, as are well known to those of ordinary skill in the art. They need not be made of the same material and they are further coupled to coils  114   a ,  114   b  to form electromagnetic devices (“magnetic device”). Coils  114   a ,  114   b , which may be made of copper or other suitable electric conductors, are coupled to one or more current sources for generating magnetic fields when current passes through the coils  114   a ,  114   b . In another embodiment one of the pole pieces need not include a coil as long, as it is formed of a ferromagnetic material. 
         [0025]    Actuator  100  further includes structural elements  102 ,  104  and first and second biasing elements  106 ,  108  to form a frame for the actuator  100 . It should be noted that structural elements  102 ,  104  and biasing elements  106 ,  108  can be manufactured out of a single piece of material such as metal or plastic. Alternatively, structural elements  102 ,  104  and biasing elements  106 ,  108  may be manufactured independently. First structural element  102 , as shown in  FIG. 1 , includes appertures  120 ,  122 , which are used for coupling or fastening to a housing, a display or a touch-sensitive panel. Similarly, structural element  104  also contains appertures  124 ,  126  for similar coupling. Structural elements  102 ,  104  are made of reasonably rigid materials, such as plastic, aluminum, and the like, for providing physical support for the pole pieces  110 ,  112 . Biasing elements  106 ,  108 , which may be springs, flexure springs, flexible blades, flexible members, elastomeric components, foam components, and the like, are made of elastic or relatively flexible materials that can be compressed and/or stretched within a predefined range. In one embodiment the biasing elements  106 ,  108  and structural elements  102 ,  104  are made of a plastic material with the biasing elements formed to be made thinner (and hence more flexible) than the structural elements. 
         [0026]    Referring again to  FIG. 1 , pole pieces  110  and  112  are coupled to structural elements  102  and  104 , respectively. Pole piece  110  is placed adjacent to pole piece  112  with three magnetic gaps  140 ,  142  and  144  between the pole pieces  110 ,  112 . The width of the gap  144  situated between the main bodies of the pole pieces  110 ,  112  is, in one embodiment, in a range of about 1 to about 5 millimeters (“mm”). The width of the gaps  140 ,  142  is in one embodiment, in a range of about 0.25 to about 0.75 mm. Air pockets  130 ,  132 , which can be of any shape, provide space for pole pieces  110 ,  112  to move. They are not required, however. Because gaps  140 ,  142  are much smaller than gap  144  the attractive magnetic force at gaps  140 ,  142  dominates over any attractive force across gap  144 . 
         [0027]    In operation, the biasing elements  106 ,  108  provide minimal force if there is no current passing through the coils  114  and the actuator is (accordingly) in a relaxed state. Under this no power condition, the actuator attains a first equilibrium position as shown, for example, in  FIG. 1 . When power is applied to coil(s)  114   a ,  114   b  an input current passes through the coil(s) creating magnetic flux lines  150  in the pole pieces  110 ,  112  and across gaps  140 ,  142 . This process acts to generate an attractive force or attractive magnetic force between the pole pieces  110 ,  112  when the coils are wound so that the electromagnetic effects do not cancel one another. The term attractive force and attractive magnetic force are used interchangeably herein. The attractive magnetic force acts against the biasing elements  106 ,  108  and pulls the pole pieces  110 ,  112  closer together at the gaps  140 ,  142 . In accordance with the embodiment shown in  FIG. 1 , under the attractive magnetic force, with structural element  102  held fixed, the pole piece  112  moves in a direction from right to left (as indicated by arrow  138 ) toward the pole piece  110 . Pole piece  110 , in this embodiment, may be fastened or secured to structural element  102 , which may be further secured to a housing, touch-sensitive panel or display device. When one of the pole pieces  110 ,  112  is displaced enough distance within the gaps  140 ,  142 , a second equilibrium position is reached as increasing spring force is applied in an opposite direction by biasing elements  106 ,  108 . When power is then reduced or removed, the biasing elements  106 ,  108  force the pole pieces  110 ,  112  back to their original no-power position, also known as the first equilibrium position as described earlier. 
         [0028]    It should be noted that the attractive force can be manipulated by varying an amount of current passing through the coils  114   a ,  114   b . Accordingly, the acts of varying the magnitude, duration and pulse repetition of current passing through the coils  114   a ,  114   b  can be used to vary the level and quality of sensation provided by the haptic effect. It should be further noted that the haptic effect, which is also known as tactile, force feedback or haptic sensation, can be a pulse, vibration, spatial texture, weight or other physical properties sensible through feeling and touch. The term haptic effect and haptic sensation will be used interchangeably herein. 
         [0029]    The present invention allows a user to manipulate the frequency of the movements between the pole pieces  110 ,  112  by adjusting the periodicity of applied input current. The input current means a current passing through the coils  114   a ,  114   b  for generating magnetic fields and magnetic flux in the pole pieces  110 ,  112  and across the magnetic gaps  140 ,  142 . It should be noted that input currents having different waveform shapes will produce different haptic effect; when an input current is in a square waveform, the haptic effect will be different than when the input current waveform has a sinusoidal shape. In one embodiment, the frequency of haptic effects may have a range between about 40 and about 300 Hertz (Hz). 
         [0030]    An advantage of using such a magnetic circuit with an actuator  100  as described above is to efficiently generate force. Unlike other methods, a permanent magnet is not required to implement the present invention. One could be included to add a small magnetic bias to the magnetic circuit, however. Another advantage of actuator  100  is that it may be made very compact in size. For example, in one embodiment actuator  100  may be about 1.5 inches long, 0.6 inches high and 0.3 inches deep. Depending on the orientation of the actuator  100  with respect to a touch-sensitive panel, it can excite either in-plane or out-of-plane motion between the touch-sensitive panel and the display device for haptic sensation. It should be noted that the L-shaped pole pieces as illustrated in  FIG. 1  represent merely one embodiment and other arrangements of the pole pieces may also be used although the L-shaped pole pieces are believed to be relatively space efficient for this application. 
         [0031]      FIG. 2  illustrates two alternative embodiments of electromagnet components  200  and  220  capable of generating attractive magnetic force in accordance with the present invention. Electromagnet component  200  includes a C-shaped pole piece  202 , an I-shaped pole piece  204 , and a single coil  206 . Pole pieces  202 ,  204  may be made of any suitable ferromagnetic materials as discussed above. 
         [0032]    C-shaped pole piece  202  is placed adjacent to pole piece  204  with two gaps  208 . The width of the gap  208  is approximately 0.5 mm. When the input current passes through the coils  206 , a magnetic flux  210  is generated. Magnetic flux  210  generates the attractive magnetic force between the pole pieces  202 ,  204 . The attractive magnetic force causes the pole piece  204  to move closer to the pole piece  202 . Alternatively, the attractive magnetic force can cause pole piece  202  to move closer to pole piece  204  if pole piece  204  is relatively fixed. Haptic effects may be generated by the movements caused by the attractive magnetic force between the pole pieces  202 ,  204 . 
         [0033]    Electromagnet component  220  includes an E-shaped pole piece  222 , an I-shaped pole piece  224 , and a coil  226 . Pole pieces  222 ,  224  may be constructed as discussed above. E-shaped pole piece  222  is placed adjacent to the I-shaped pole piece  224  with a gap  228 . The width of the gap  228  is approximately 0.5 mm. When the input current passes through coils  226 , magnetic flux lines  230  are generated. Magnetic flux lines  230  cause an attractive magnetic force between pole pieces  222 ,  224 . The attractive magnetic force causes pole piece  224  to move closer to pole piece  222  and effectively narrow the width of the gap  228 . In another embodiment, the attractive magnetic force causes the pole piece  222  to move closer to pole piece  224  if pole piece  224  is fastened to housing. A haptic effect may be generated by movements between the pole pieces. 
         [0034]      FIG. 3  is an actuator  300  illustrating an alternative embodiment of the actuator illustrated in  FIG. 1  in accordance with one embodiment of the present invention. Actuator  300  includes two L-shaped pole pieces  110 ,  112 , structural elements  102 ,  104 , and biasing element  302 . Pole pieces  110 ,  112  are further coupled to coils  114   a ,  114   b  to form magnetic devices. Coils  114   a ,  114   b  are coupled to one or more current sources for causing magnetic flux in pole pieces  110 ,  112 . 
         [0035]    Actuator  300  further includes structural elements  102 ,  104  and biasing element  302  to form a frame. It should be noted that structural elements  102 ,  104  and biasing element  302  can be manufactured at the same time and on a single frame. Alternatively, structural elements  102 ,  104  and biasing element  302  may be formed as separate structures that are then assembled together. Structural elements  102 ,  104  are fabricated or discussed above to provide physical support for the pole pieces  110 ,  112 . Biasing element  302 , which may be formed as described above, is made of an elastic material that may be compressed or stretched within a predefined range. Referring to  FIG. 3 , it should be noted that biasing element  302  may be located anywhere as long as it is coupled with structural elements  102 ,  104  and provides its biasing or spring function in opposition to the attractive gap-closing magnetic force of the magnetic devices. 
         [0036]      FIG. 4  is an alternative embodiment of an actuator  400  in accordance with one embodiment of the present invention. Actuator  400  includes two L-shaped pole pieces  110 ,  112 , structural elements  102 ,  104 , and biasing elements  402 ,  404 . Pole pieces  110 ,  112  are further coupled to coils  114   a ,  114   b  to form magnetic devices. Coils  114   a ,  114   b  are coupled to one or more current sources for creating magnetic flux in pole pieces  110 ,  112 . 
         [0037]    Actuator  400  further includes structural elements  102 ,  104  and biasing elements  402 ,  404  to form a frame that allows some movements between the structural elements  102 ,  104 . It should be noted that structural elements  102 ,  104  and biasing elements  402 ,  404  are manufactured separately and they need to be assembled to form a frame. Structural elements  102 ,  104  are made of rigid materials, such as plastic, steel, aluminum, and so forth, to provide physical support for the pole pieces  110 ,  112 . Biasing elements  402 ,  404  may be implemented as discussed above and may be made of elastic materials that can be compressed or stretched within a predefined range. Referring to  FIG. 4 , it should be noted that any type of biasing element may be used as long as it facilitates movement between the pole pieces  110 ,  112  and may be arranged to counter the attractive gap-closing force of the magnetic devices. 
         [0038]      FIG. 5  illustrates a system having an actuator  100  in accordance with one embodiment of the present invention. The system includes a case  502 , a touch-sensitive panel  504 , and an actuator  100 . Actuator  100  includes two L-shaped pole pieces  110 ,  112 , structural elements  102 ,  104 , and biasing elements  106 ,  108 . Pole pieces  110 ,  112  are further coupled to coils  114   a ,  114   b  to form magnetic devices. Coils  114   a ,  114   b  are coupled to one or more current sources for creating magnetic flux in pole pieces  110 ,  112 . Biasing elements  106 ,  108  may be implemented as discussed above and may be made of elastic materials that may be compressed or stretched within a predefined range. 
         [0039]    Referring to  FIG. 5 , one side of actuator  100  is coupled to the case  502  while another side of actuator  100  is coupled to the touch-sensitive panel  504 . Structural element  102 , as shown in  FIG. 5 , is fastened to the case  502 . In this embodiment, the case  502  is rigid and does not move easily. In one embodiment, appertures  120 ,  122  may be used by fasteners to couple the structural element  102  to the case  502 . Structural element  104  is, in turn fastened to a touch-sensitive panel  504 . Touch-sensitive panel  504 , in one embodiment, may be made of relatively flexible transparent materials. In one embodiment, holes  124 ,  126  may be used to fasten the structural element  104  to the touch-sensitive panel  504 . 
         [0040]    When power is applied and input current begins to pass through the coils  114   a ,  114   b , the attractive gap-closing force between pole pieces  110  and  112  starts to increase. The attractive force causes the pole piece  112  to be attracted to the pole piece  110  where pole piece  110  is held fixed. Pole piece  112  begins to move toward the pole piece  110  to close the gaps  140 ,  142  until it reaches a second equilibrium position as illustrated in  FIG. 6 . When power is reduced or removed, the attractive force between pole pieces  110  and  112  begins to reduce and consequently, the pole piece  112  begins to move back to its original position in response to the return force provided by the biasing elements  106 ,  108 . The biasing elements  106 ,  108  continue to force the pole piece  112  to move back until it reaches the first equilibrium position as shown in  FIG. 1 . The movements between the pole pieces  110 ,  112  cause similar movements between the structural elements  102 ,  104 . In one embodiment, the movements between the structural elements  102 ,  104  generate haptic effects or haptic sensation. Since touch-sensitive panel  504  is fastened to structural element  104 , haptic effects on the touch-sensitive panel  504  occur when the movement between the structural elements  102 ,  104  occurs. Depending on the orientation of the actuator  100  with respect to the touch-sensitive panel  504 , haptic effects may excite either in-plane or out-of-plane motion with respect to the touch-sensitive panel  504 . 
         [0041]      FIG. 6  illustrates, in a somewhat exaggerated manner to improve visibility, a second equilibrium position of an actuator  600  in accordance with one embodiment of the present invention. Actuator  600 , which is similar to actuator  100 , includes two L-shaped pole pieces  110 ,  112 , structural elements  102 ,  104 , and biasing elements  602 ,  604 . Pole pieces  110 ,  112  are further coupled to coils  114   a ,  114   b  to form magnetic devices. Coils  114   a ,  114   b  are coupled to one or more current sources for generating magnetic flux in pole pieces  110 ,  112 . 
         [0042]    When power is off, the biasing elements  602 ,  604  provide minimal force to keep the actuator  600  in the first equilibrium position as described and shown in  FIG. 1 . When power is on, the input current passes through the coils  114  and generates magnetic flux in the pole pieces  110 ,  112 . Magnetic flux causes an attractive magnetic force between the pole pieces  110 ,  112  across gaps  140 , 142 . The attractive magnetic force acts against the biasing elements  602 ,  604  and pulls the pole pieces  110 ,  112  closer together at the gaps  140 ,  142 . Pole piece  110 , in this embodiment, may be secured to a case via the structural element  102 , while pole piece  112  is secured to a touch-sensitive panel via the structural element  104 . The attractive magnetic force causes the pole piece  112  to move from right to left (as indicated by  138 ) toward the pole piece  110 . When the pole piece  110  is displaced enough distance, a second equilibrium position is reached as shown in  FIG. 6 . When power is reduced or removed, the biasing elements  602 ,  604  force the pole piece  112  back to the first equilibrium position as discussed earlier. 
         [0043]      FIG. 7  illustrates a system configuration having an actuator in accordance with one embodiment of the present invention. The system configuration includes a touch-sensitive panel  702 , a display panel  704 , and a case  706 . Touch-sensitive panel  702 , in one embodiment, is made of substantially transparent materials, and is capable of transmitting light so that objects or images displayed in the display  704  may be seen through the touch-sensitive panel  702 . The display  704  can be any type of display such as a cathode ray tube (CRT), liquid crystal display (LCD), plasma display, flat panel display or the like or could even be a static illustration. Both touch-sensitive panel  702  and display  704  may be installed in the case  706 . In an alternative embodiment, the touch-sensitive panel  702  and the display  704  may be located separately with the actuator mounted between the touch-sensitive panel  702  and a relatively fixed location so that haptic effects are provided to the touch-sensitive panel but the display is located elsewhere. 
         [0044]    In one embodiment, touch-sensitive panel  702  is further divided into various regions  720  and the regions are further separated by borders  722 . Touch-sensitive panel  702  accepts a user&#39;s selection when only a region  720  is touched. Conversely, touch-sensitive panel  702  rejects a user&#39;s selection when a border  722  is touched. Touch-sensitive panel  702  further includes four actuators  710  and, depending on their orientation, actuators  710  can excite either in-plane or out-of-plane motion with respect to the touch-sensitive panel  702  for haptic sensation. Actuators  710  may be installed to move touch-sensitive panel for relative to display  704 . 
         [0045]      FIG. 8  is a flow diagram illustrating a method for generating a haptic effect in accordance with one embodiment of the present invention. A process for generating haptic sensation starts at block  802 . In one embodiment, the process can be activated by a user who touches a touch-sensitive panel possibly in a predetermined location or locations. In another embodiment, the process is activated by a touch signal or contact signal sent by the touch-sensitive panel, which indicates that a selection has been made by a user. 
         [0046]    At block  804 , the process receives a contact signal from the touch-sensitive, which may be sent by a touch-sensitive panel according to a selection made by a user. In another embodiment, a computer or controller sends a contact signal. Upon receipt of the contact signal, the process moves to the next block  806 . 
         [0047]    At block  806 , the process instructs a controller to provide an input current according to the contact signal. In one embodiment, the input current is passing through at least one electromagnet device of an actuator to generate magnetic flux in a pair of pole pieces. 
         [0048]    At block  808 , the magnetic flux creates attractive magnetic force between the electromagnet devices which opposes a biasing force imparted by biasing elements arranged to counter the attractive magnetic force. The attractive magnetic force causes the pole pieces of the electromagnet devices to attract to each other. The process moves to the next block. 
         [0049]    At block  810 , the attractive magnetic force creates a movement between the electromagnet devices. In one embodiment, one pole piece of one electromagnet device is physically moved closer to another pole piece of another electromagnet device. At block  812 , the current is removed. At block  814 , a biasing element provides a bias force or return force to control the movement between the electromagnet devices within a predefined range. When the power is reduced or turned off in block  812 , the pole pieces of electromagnet devices move back to their original positions. 
         [0050]    With turning on and off the power continuously, a continuous movement between the electromagnet devices is created. Accordingly, the haptic effect is generated in response to the movement between the electromagnet devices. It should be noted that the frequency and amplitude of the movements between the electromagnet devices can be controlled by controlling the input current. 
         [0051]      FIG. 9  is a block diagram illustrating a system having an actuator in accordance with one embodiment of the present invention. The system includes a computer or central processing unit (CPU)  906  with appropriate interfaces  908  to a memory  910  for storing program steps for controlling the processor  906 ,  912  for controlling a display device  914 ,  916  for communicating with a touch-sensitive panel  918  and  920  for driving an amplifier circuit (if required) which in turn drives actuator  924 . Actuator  924  is arranged to create relative movement between display device  914  and touch-sensitive panel  918 . The relative movement may be in the plane of the touch-sensitive panel, out of the plane of the touch-sensitive panel, or same combination of the two. When the touch panel  904  is touched or depressed, it sends a contact signal to computer  906  via connection  926 . The contact signal indicates that the touch panel has been selected or touched. Computer  906 , which can be any general purpose computer operating under the control of suitable software and for firmware, is coupled to amplifier  922  via connection  928  and instructs amplifier  922  to provide input current to the actuator  924  over connection  930 . Upon receipt of an instruction from the computer  906 , amplifier  922  provides an input current to the actuator  924  via connection  930 . Actuator  924  provides a haptic sensation or effect to the touch-sensitive panel  918 . The processor  906  (or, potentially, another device (not shown) provides a display image or image to display device  914 . 
         [0052]    In the foregoing specification the invention has been described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader scope of the invention. For example, if desired, two or more actuators could be attached together to provide multiple inputs to generate haptic effects and/or to increase the haptic effect and/or a component to be haptically effected could be arranged so that actuators are arranged to be able to pull it in more than one direction. Accordingly, the specification and drawings are to be regarded in an illustrative rather than restrictive sense.