Patent Application
20080068334
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.
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.
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.
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's modulus and moment is typically applied, i.e., where deflection=EI=flexural modulus of elasticity (force×length2)×moment of inertia (length4). 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.
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.
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.
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.
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
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'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.
In one embodiment, the appearance and state of each of the buttons 20 of
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.
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
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.
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.
