Abstract:
A surface that generates a haptic feedback includes a first region having a first level of stiffness and a second region having a second level of stiffness that is less than the first level of stiffness. The second region defines a deformation region within which the haptic feedback is generally localized.

Description:
FIELD OF THE INVENTION 
       [0001]    One embodiment of the present invention is directed to haptic feedback. More particularly, one embodiment of the present invention is directed to localizing haptic feedback to a specific region. 
       BACKGROUND INFORMATION 
       [0002]    Humans interface with electronic and mechanical devices in a variety of applications, and the need for a more natural, easy-to-use, and informative interface is a constant concern. In an automotive environment, the predominate interface is still a mechanical button or dial. One reason for the popularity of this kind of interface is that the driver of an automobile typically must engage a button or dial while maintaining a view of the road. Mechanical devices allow the driver to feel a mechanical button or dial. 
         [0003]    However, having mechanical buttons and dials introduces several disadvantages. For one, any type of mechanical interface is subject to wear and degradation. Second, buttons and dials on an automobile dashboard include cracks and crevices that build up dirt and become unsightly and unsanitary. Finally, many automobile manufacturers attempt to create a dashboard having a futuristic sleek look, and mechanical buttons can detract from this appearance. 
         [0004]    It is known to use force feedback or tactile feedback (collectively referred to herein as “haptic feedback”) in combination with a touchpad or touch control “buttons” in order to eliminate mechanical buttons. However, known haptic feedback devices tend not to isolate the feedback (i.e., vibration) within the boundaries of a specific “button”. In many environments, this might not be a large problem. However, in an automobile environment and other environments where a user is not looking at the button when it is being “pressed”, it is more important to isolate the haptic feedback to only the targeted region. 
         [0005]    Based on the foregoing, there is a need for a system and method in which haptic feedback is applied to a touch control so that the feedback is isolated to a targeted region. 
       SUMMARY OF THE INVENTION 
       [0006]    One embodiment of the present invention is a surface that generates a haptic feedback. The surface includes a first region having a first level of stiffness and a second region having a second level of stiffness that is less than the first level of stiffness. The second region defines a deformation region within which the haptic feedback is generally localized. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a plan view of the front side of an automotive dashboard in accordance with one embodiment of the present invention. 
           [0008]      FIG. 2  is a cross-sectional view of the rear side of a surface and an actuator in accordance with one embodiment of the present invention. 
           [0009]      FIG. 3  is a plan view of a portion of the rear side of the surface in accordance with one embodiment of the present invention. 
           [0010]      FIG. 4  is a plan view of a portion of the rear side of the surface in accordance with one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    One embodiment of the present invention is a surface having a reduced stiffness region and an actuator coupled to the region. The actuator creates an isolated haptic feedback effect within the reduced stiffness region. 
         [0012]      FIG. 1  is a plan view of the front side of an automotive dashboard  10  in accordance with one embodiment of the present invention. Dashboard  10  is formed from a contiguous surface or panel  12 . A plurality of buttons  20  are formed on surface  12 . A steering wheel  14  is coupled to dashboard  10 . Other components typically present on a dashboard, such as gauges, dials, etc., are not shown in  FIG. 1 . 
         [0013]    Each button  20  in one embodiment is represented on the front side of dashboard  10  as a graphical icon or other indication of the geographic location of the button. Otherwise, surface  12  in the areas of buttons  20  is contiguous and smooth on the front side, and includes no cracks or crevices that can be unsightly and retain dirt. 
         [0014]    In one embodiment, surface  12  is formed from a layer of wood laminated to a layer of metal. The wood layer is on the front side of surface  12 . In other embodiments, surface  12  can be formed of other materials such as, for example, glass, plastic, composite materials such as carbon fiber, and stone. In one embodiment, in each area substantially behind the location of each button  20 , a portion of the metal and wood layers from the rear side of surface  12  is removed to create a thinner region having a lower level of stiffness than the regions of surface  12  that are not altered or thinned. 
         [0015]    In general, “stiffness” disclosed herein, i.e., flexural or bending stiffness, relates to the amount of deflection of a material resulting from an applied normal force. This is a function of cross-section (thickness), location of the applied force, and a material property of the material used. When defining stiffness, the concept of Young&#39;s modulus and moment is typically applied, i.e., where deflection=EI=flexural modulus of elasticity (force×length 2 )×moment of inertia (length 4 ). However, typical calculations for EI use “Timoshenko” equations which assume constant cross section, rigid supports at the ends and homogenous materials. In embodiments of the present invention, stiffness is the result of a cross-section that is varied so as to direct forces toward a location, such as where a button and actuator(s) are positioned. In one embodiment, more than one material is used, such as in a laminate or other form of composite. For instance, with the laminate, the cross section of one or more of the materials can be varied or different materials, having a different modulus may be used in the deformable region which may or may not change the total cross section, and yet both can contribute to a designed stiffness. In one embodiment, features such as rings or other local features can contribute to a chosen stiffness response to a user. In this manner, an effective or resulting stiffness can be tailored by design. Therefore, values for a stiffness resulting from a force applied at a given location may have to be determined either empirically or through finite element analysis. The embodiments disclosed are but a few ways to tailor stiffness and are not meant to be limiting or exhaustive in the methods available. 
         [0016]    The region having a lower level of stiffness forms a deformable region, which generally coincides with the shape and location of button  20 . An actuator is coupled to the deformable region to create a haptic effect that is substantially isolated and concentrated within the deformable region. Therefore, the deformable region is the approximate region that moves through contact with the actuator. 
         [0017]      FIG. 2  is a cross-sectional view of the rear side of surface  12  and an actuator  50  in accordance with one embodiment of the present invention. Surface  12  includes a deformable region  40  which is formed by a removal of material from the rear side of surface  12 . In one embodiment, surface  12  in regions that have not had material removed has a thickness of approximately 4.5 mm, and deformable region  40  has a thickness of approximately 1.5 mm. 
         [0018]    Actuator  50  is coupled to the back side of surface  12  in an area other than deformable region  40 . Actuator  50  includes a stationary electromagnet  34 , a floating electromagnet  32 , and a copper coil  36 . A shaft  30  is attached to a plunger  38  and is embedded within floating electromagnetic  32 . 
         [0019]    In a no-power condition, plunger  38  rests or is fixed against the back (non-visible side) of deformable region  40 . If plunger  38  is not fastened to the surface, a low spring force presses plunger  38  against the surface to prevent it from rattling during normal environmental conditions, such as driving a car over bump. When power is supplied to copper coil  36 , electromagnets  32  and  34  are attracted to each other, creating substantial force. This force acts against a return spring (not shown) and pushes plunger  38  (if not attached to the surface) or pulls plunger  38  (if attached to the surface) to move the surface at deformable region  40 , thereby deforming the surface to create a vibration or haptic effect. In one embodiment, the surface itself may function as the return spring. 
         [0020]    Although actuator  50  is an electromagnetic type of actuator, any type of actuator can be used that can apply a haptic effect or force to surface  12  at deformable region  40 . For example actuator  50  may be a “smart material” such as piezoelectric, electro-active polymers or shape memory alloys. Although actuator  50  is coupled to surface  12  both inside and outside region  40  in  FIG. 2 , in another embodiment actuator  50  may only be coupled to region  40 . In this embodiment, actuator  50  may be an Eccentric Rotating Mass (“ERM”) in which an eccentric mass is moved by a motor, or a Linear Resonant Actuator (“LRA”) in which a mass attached to a spring is driven back and forth. In another embodiment, actuator  50  may be coupled to surface  12  inside region  40  and coupled to a separate grounded element, such as a frame or structural member. Further, a controller and other necessary components are coupled to actuator  50  in order to create the signals and power to actuator  50  to create the haptic effects. 
         [0021]      FIG. 3  is a plan view of a portion of the rear side of surface  12  in accordance with one embodiment of the present invention. Region  64  is the region where material from surface  12  was removed to create a reduced stiffness region. The remainder of the portion of surface  12  shown in  FIG. 3 , region  62 , has not had any material removed. In the embodiment shown in  FIG. 3 , region  64  approximately coincides with a deformable region of surface  12 , and haptic effects that are applied by an actuator coupled to region  64  will be substantially isolated within region  64 . 
         [0022]    In another embodiment, region  64  has a tapered surface thickness forming a graduated reduced stiffness region rather than a constant surface thickness. The tapering can be formed by removing more material from the center of region  64  than from the edges in a generalized “V” shape. This creates a haptic effect that gets stronger at the center of region  64  and will produce the benefit of directing a user&#39;s finger which is on the edge of region  64  to the center of region  64 . Thus, for example, a driver in an automobile can have their finger directed to a button through haptic feedback without having to look at the button. 
         [0023]      FIG. 4  is a plan view of a portion of the rear side of surface  12  in accordance with one embodiment of the present invention. Region  74  is the region where material from surface  12  was removed to create a reduced stiffness region. The remainder of the portion of surface  12  shown in  FIG. 4 , regions  72  and  76 , have not had any material removed. In the embodiment shown in  FIG. 4 , the deformable region of surface  12  is approximately surrounding reduced thickness region  74  in combination with region  76 . Thus, a portion of surface  12 , region  76 , is part of the deformable region even though it has not had material removed to form a reduced stiffness region. In the embodiment of  FIG. 4 , haptic effects that are applied by an actuator coupled to region  76  will be substantially isolated within regions  74  and  76 . 
         [0024]    In one embodiment, the appearance and state of each of the buttons  20  of  FIG. 1  on the front side of surface  12  is enhanced by the addition of an electroluminescent luminescent layer and light emitting diodes (“LED&#39;s”) applied on the rear side of surface  12  at the location of buttons  20 . The luminescent layer creates illumination allowing the icons for the buttons to be visible at night giving the appearance of back lighting. When a button  20  is pressed, to provide further feedback to the user, LEDs may be turned on or off to indicate the state of a device controlled by a button, for example the level of heat for a heated seat. 
         [0025]    Although embodiments disclosed above are of an automotive dashboard, the present invention can be implemented on a surface of any other type of device where isolated haptic effects are desired. Other embodiments can include aircraft buttons, buttons on appliances such as refrigerators, and buttons on medical devices where cleanliness concerns dictate having a smooth button surface. In another embodiment, rather than having an icon or other indicator of the presence of the button, the button is unmarked. This embodiment is useful for creating a hidden wall switch where the button is undetectable except when it is pressed and the isolated haptic effect is generated. In addition, features other than buttons can be designed with these localized haptics effects. Such other features can be, for example, a haptically enabled surface representing a linear slider, a curved slider or a circular slider. The slider would allow a user to move a finger along the haptic enabled surface such as to select from a table or to set a volume level. 
         [0026]    As described, embodiments of the present invention create an isolated haptic effect which creates many advantages. Because the haptic effect is isolated, it is stronger and thus can be more easily felt through, for example, a driving glove. Further, multiple buttons  20  of  FIG. 1  can be pressed at the same time without having the haptic effect from one button bleeding over to the other button, and each button can be separately discernable by the user. Embodiments of the present invention allow much greater design freedom of switch placement and increased aesthetics along with needed user haptic feedback. Further, embodiments of the present invention allow context to be included in the button press because the button does not always have to feel the same due to different available haptic effects. For example, if the button functionality was not permitted at the time of an attempted press, an error buzz effect could be played instead of a standard haptic effect. Further, the isolation of the haptic effect reduces power requirements by localizing the action to a small region, and reduces potential acoustic noise generation. 
         [0027]    Although in embodiments disclosed above the reduced thickness region is created by removal of material from the rear side of the surface, other methods can be used to create a reduced thickness region. For example, instead of removal of material, material can be added to the surface in regions other than the reduced thickness region. In another embodiment, surface  12  can be formed from non-uniform materials. For example, a softer plastic region can be molded into a harder plastic base. 
         [0028]    Several embodiments of the present invention are specifically illustrated and/or described herein. However, it will be appreciated that modifications and variations of the present invention are covered by the above teachings and within the purview of the appended claims without departing from the spirit and intended scope of the invention.