Patent Application
20120126959
The present invention is directed to the use of electroactive polymer transducers to provide sensory feedback.
A tremendous variety of devices used today rely on actuators of one sort or another to convert electrical energy to mechanical energy. Conversely, many power generation applications operate by converting mechanical action into electrical energy. Employed to harvest mechanical energy in this fashion, the same type of actuator may be referred to as a generator. Likewise, when the structure is employed to convert physical stimulus such as vibration or pressure into an electrical signal for measurement purposes, it may be characterized as a sensor. Yet, the term “transducer” may be used to generically refer to any of the devices.
A number of design considerations favor the selection and use of advanced dielectric elastomer materials, also referred to as “electroactive polymers” (EAPs), for the fabrication of transducers. These considerations include potential force, power density, power conversion/consumption, size, weight, cost, response time, duty cycle, service requirements, environmental impact, etc. As such, in many applications, EAP technology offers an ideal replacement for piezoelectric, shape-memory alloy (SMA) and electromagnetic devices such as motors and solenoids.
Examples of EAP devices and their applications are described in U.S. Pat. Nos. 7,394,282; 7,378,783; 7,368,862; 7,362,032; 7,320,457; 7,259,503; 7,233,097; 7,224,106; 7,211,937; 7,199,501; 7,166,953; 7,064,472; 7,062,055; 7,052,594; 7,049,732; 7,034,432; 6,940,221; 6,911,764; 6,891,317; 6,882,086; 6,876,135; 6,812,624; 6,809,462; 6,806,621; 6,781,284; 6,768,246; 6,707,236; 6,664,718; 6,628,040; 6,586,859; 6,583,533; 6,545,384; 6,543,110; 6,376,971 and 6,343,129; and in U.S. Patent Application Publication Nos. 2008/0157631; 2008/0116764; 2008/0022517; 2007/0230222; 2007/0200468; 2007/0200467; 2007/0200466; 2007/0200457; 2007/0200454; 2007/0200453; 2007/0170822; 2006/0238079; 2006/0208610; 2006/0208609; and 2005/0157893, and U.S. patent application Ser. No. 12/358,142 filed on Jan. 22, 2009; and PCT Publication No. WO 2009/067708 the entireties of which are incorporated herein by reference.
An EAP transducer comprises two electrodes having deformable characteristics and separated by a thin elastomeric dielectric material. When a voltage difference is applied to the electrodes, the oppositely-charged electrodes attract each other thereby compressing the polymer dielectric layer therebetween. As the electrodes are pulled closer together, the dielectric polymer film becomes thinner (the z-axis component contracts) as it expands in the planar directions (along the x- and y-axes), i.e., the displacement of the film is in-plane. The EAP film may also be configured to produce movement in a direction orthogonal to the film structure (along the z-axis), i.e., the displacement of the film is out-of-plane. U.S. Patent Application Serial No. 2005/0157893 discloses EAP film constructs which provide such out-of-plane displacement—also referred to as surface deformation or thickness mode deflection.
The material and physical properties of the EAP film may be varied and controlled to customize the surface deformation undergone by the transducer. More specifically, factors such as the relative elasticity between the polymer film and the electrode material, the relative thickness between the polymer film and electrode material and/or the varying thickness of the polymer film and/or electrode material, the physical pattern of the polymer film and/or electrode material (to provide localized active and inactive areas), and the tension or pre-strain placed on the EAP film as a whole, and the amount of voltage applied to or capacitance induced upon the film may be controlled and varied to customize the surface features of the film when in an active mode.
Numerous transducer-based applications exist which would benefit from the advantages provided by such surface deformation EAP films. One such application includes the use of EAP films to produce haptic feedback (the communication of information to a user through forces applied to the user's body) in user interface devices. There are many known user interface devices which employ haptic feedback, typically in response to a force initiated by the user. Examples of user interface devices that may employ haptic feedback include keyboards, touch screens, computer mice, trackballs, stylus sticks, joysticks, etc. The haptic feedback provided by these types of interface devices is in the form of physical sensations, such as vibrations, pulses, spring forces, etc., which a user senses either directly (e.g., via touching of the screen), indirectly (e.g., via a vibrational effect such a when a cell phone vibrates in a purse or bag) or otherwise sensed (e.g., via an action of a moving body that creates a pressure disturbance but doe not generate an audio signal in the traditional sense).
Often, a user interface device with haptic feedback can be an input device that “receives” an action initiated by the user as well as an output device that provides haptic feedback indicating that the action was initiated. In practice, the position of some contacted or touched portion or surface, e.g., a button, of a user interface device is changed along at least one degree of freedom by the force applied by the user, where the force applied must reach some minimum threshold value in order for the contacted portion to change positions and to effect the haptic feedback. Achievement or registration of the change in position of the contacted portion results in a responsive force (e.g., spring-back, vibration, pulsing) which is also imposed on the contacted portion of the device acted upon by the user, which force is communicated to the user through his or her sense of touch.
One common example of a user interface device that employs a spring-back or “bi-phase” type of haptic feedback is a button on a mouse. The button does not move until the applied force reaches a certain threshold, at which point the button moves downward with relative ease and then stops—the collective sensation of which is defined as “clicking” the button. The user-applied force is substantially along an axis perpendicular to the button surface, as is the responsive (but opposite) force felt by the user.
In another example, when a user enters input on a touch screen the, screen confirms the input typically by a graphical change on the screen along with/without an auditory cue. A touch screen provides graphical feedback by way of visual cues on the screen such as color or shape changes. A touch pad provides visual feedback by means of a cursor on the screen. While above cues do provide feedback, the most intuitive and effective feedback from a finger actuated input device is a tactile one such as the detent of a keyboard key or the detent of a mouse wheel. Accordingly, incorporating haptic feedback on touch screens is desirable.
Haptic feedback capabilities are known to improve user productivity and efficiency, particularly in the context of data entry. It is believed by the inventors hereof that further improvements to the character and quality of the haptic sensation communicated to a user may further increase such productivity and efficiency. It would be additionally beneficial if such improvements were provided by a sensory feedback mechanism which is easy and cost-effective to manufacture, and does not add to, and preferably reduces, the space, size and/or mass requirements of known haptic feedback devices.
The present invention includes devices, systems and methods involving electroactive transducers for sensory applications. In one variation, a user interface device having sensory feedback is provided. One benefit of the present invention is to provide the user of a user interface device with haptic feedback whenever an input is triggered by software or another signal generated by the device or associated components.
In one example, the actuators can be driven by an audio signal that is separately generated by the device. Accordingly, the disclosure includes a method of producing a haptic effect in a user interface device simultaneously with a sound generated by a separately generated audio signal. One variation of this method includes routing the audio signal to a filtering circuit; altering the audio signal to produce a haptic drive signal by filtering a range of frequencies below a predetermined frequency; and providing the haptic drive signal to a power supply coupled to an electroactive polymer transducer such that the power supply actuates the electroactive polymer transducer to drive the haptic effect simultaneously to the sound generated by the audio signal.
The method can include driving the electroactive polymer transducer to generate a sound effect using the filtered signal. Typically the predetermined frequency comprises an optimal frequency of the electroactive polymer actuator. For some EPAM devices this pre-determined frequency comprises 200 hertz.
In another variation, the method includes filtering the positive portion of an audio waveform of the audio signal to produce the haptic signal for a single phase actuator. In another variation, the method includes using a two phase electroactive polymer actuator and where altering the audio signal comprises filtering a positive portion of an audio waveform of the audio signal to drive a first phase of the electroactive polymer transducer, and inverting a negative portion of the audio waveform of the audio signal to drive a second phase of the electro active polymer transducer to improve performance of the electro active polymer transducer.
The following disclosure also includes transducers comprising an electroactive polymer film comprising a dielectric elastomer layer, wherein a portion of the dielectric elastomer layer is stretched between first and second electrodes wherein at least one overlapping portion of the electrodes defines an active film region with at least one remaining portion of film defining an inactive film region; a first conductive layer disposed on at least a portion of the inactive film region and electrically coupled to the first electrode, and a second conductive layer disposed on at least a portion of the inactive film region and electrically coupled to the second electrode; and at least one passive incompressible polymer layer, the incompressible polymer layer extending over at least a portion of one side of the electroactive polymer film, wherein activation of the active region changes a thickness dimension of the incompressible passive polymer layer.
The transducer can optionally comprise a first and a second passive incompressible polymer layers, where the first and second passive incompressible polymer layers are located on each side of the electroactive polymer film.
In another variation, transducer assembly can include at least two stacked layers of electroactive polymer film, each electroactive polymer film comprising a thin dielectric elastomer layer, wherein a portion of the dielectric elastomer layer is sandwiched between first and second electrodes wherein the overlapping portions of the electrodes define an active film region with the remaining portion of film defining an inactive film region, wherein the active film regions of the respective layers of electroactive polymer film are in stacked alignment and the inactive active film regions of the respective layers of electroactive polymer film are in stacked alignment; a first conductive layer disposed on at least a portion of the inactive film region of each electroactive polymer film and electrically coupled to the first electrode thereof; and a second conductive layer disposed on at least a portion of the inactive film region of each electroactive polymer film and electrically coupled to the second electrode thereof; and a passive incompressible polymer layer over each exposed side of the electroactive polymer films, wherein activation of the active regions changes a thickness dimension of the passive incompressible polymer layer.
The following disclosure also includes inertial electroactive polymer transducer. In one variation, an inertial electroactive polymer transducer includes an electroactive polymer film stretched between a top and bottom frame components, where a central portion of frame is open to expose a central surface of the electroactive polymer film; a first output member on the central surface of the electroactive polymer film; and at least one inertial mass affixed to the output disk wherein upon application of voltage difference across a first and second electrodes on the electroactive polymer film causes displacement of the polymer film causing the inertial mass to move.
Additional variations of an inertial electroactive polymer tranducer include a second electroactive polymer film sandwiched between a top and bottom second frame components, where a central portion of second frame is open to expose a second central surface of the electroactive polymer film; and a second output member on the central surface of the electroactive polymer film, where the inertial mass is located between the affixed between the first and second output members.
The present devices and systems provide greater versatility as they can be employed within many types of input devices and provide feedback from multiple input elements. The system is also advantageous, as it does not add substantially to the mechanical complexity of the device or to the mass and weight of the device. The system also accomplishes its function without any mechanical sliding or rotating elements thereby making the system durable, simple to assemble and easily manufacturable.
The present invention may be employed in any type of user interface device including, but not limited to, touch pads, touch screens or key pads or the like for computer, phone, PDA, video game console, GPS system, kiosk applications, etc.
As for other details of the present invention, materials and alternate related configurations may be employed as within the level of those with skill in the relevant art. The same may hold true with respect to method-based aspects of the invention in terms of additional acts as commonly or logically employed. In addition, though the invention has been described in reference to several examples, optionally incorporating various features, the invention is not to be limited to that which is described or indicated as contemplated with respect to each variation of the invention. Various changes may be made to the invention described and equivalents (whether recited herein or not included for the sake of some brevity) may be substituted without departing from the true spirit and scope of the invention. Any number of the individual parts or subassemblies shown may be integrated in their design. Such changes or others may be undertaken or guided by the principles of design for assembly.
These and other features, objects and advantages of the invention will become apparent to those persons skilled in the art upon reading the details of the invention as more fully described below.
The invention is best understood from the following detailed description when read in conjunction with the accompanying schematic drawings. To facilitate understanding, the same reference numerals have been used (where practical) to designate similar elements that are common to the drawings. Included in the drawings are the following:
Variation of the invention from that shown in the figures is contemplated.
The devices, systems and methods of the present invention are now described in detail with reference to the accompanying figures.
As noted above, devices requiring a user interface can be improved by the use of haptic feedback on the user screen of the device.
A number of design considerations favor the selection and use of advanced dielectric elastomer materials, also referred to as “electroactive polymers” (EAPs), for the fabrication of transducers especially when haptic feedback of the display screen 232 is sought. These considerations include potential force, power density, power conversion/consumption, size, weight, cost, response time, duty cycle, service requirements, environmental impact, etc. As such, in many applications, EAP technology offers an ideal replacement for piezoelectric, shape-memory alloy (SMA) and electromagnetic devices such as motors and solenoids.
An EAP transducer comprises two thin film electrodes having elastic characteristics and separated by a thin elastomeric dielectric material. When a voltage difference is applied to the electrodes, the oppositely-charged electrodes attract each other thereby compressing the polymer dielectric layer therebetween. As the electrodes are pulled closer together, the dielectric polymer film becomes thinner (the z-axis component contracts) as it expands in the planar directions (the x- and y-axes components expand).
In any case, the display screen 232 includes a frame 234 (or housing or any other structure that mechanically connects the screen to the device via a direct connection or one or more ground elements), and an electroactive polymer (EAP) transducer 236 that couples the screen 232 to the frame or housing 234. As noted herein, the EAP transducers can be along an edge of the screen 232 or an array of EAP transducers can be placed in contact with portion of the screen 232 that are spaced away from the frame or housing 234.
The figures show the user interface device 230 cycling the touch screen 232 between an inactive and active state.
It is noted that the figures discussed above schematically illustrate exemplary configurations of such tactile feedback devices that employ EAP films or transducers. Many variations are within the scope of this disclosure, for example, in variations of the device, the EAP transducers can be implemented to move only a sensor plate or element (e.g., one that is triggered upon user input and provides a signal to the EAP transducer) rather then the entire screen or pad assembly.
In any application, the feedback displacement of a display screen or sensor plate by the EAP member can be exclusively in-plane which is sensed as lateral movement, or can be out-of-plane (which is sensed as vertical displacement). Alternatively, the EAP transducer material may be segmented to provide independently addressable/movable sections so as to provide angular displacement of the plate element. In addition, any number of EAP transducers or films (as disclosed in the applications and patent listed above) can be incorporated in the user interface devices described herein.
The variations of the devices described herein allows the entire sensor plate (or display screen) of the device to act as a tactile feedback element. This allows for extensive versatility. For example, the screen can bounce once in response to a virtual key stroke or, it can output consecutive bounces in response to a scrolling element such as a slide bar on the screen, effectively simulating the mechanical detents of a scroll wheel. With the use of a control system, a three-dimensional outline can be synthesized by reading the exact position of the user's finger on the screen and moving the screen panel accordingly to simulate the 3D structure. Given enough screen displacement, and significant mass of the screen, the repeated oscillation of the screen may even replace the vibration function of a mobile phone. Such functionality may be applied to browsing of text where a scrolling (vertically) of one line of text is represented by a tactile “bump”, thereby simulating detents. In the context of video gaming, the present invention provides increased interactivity and finer motion control over oscillating vibratory motors employed in prior art video game systems. In the case of a touchpad, user interactivity and accessibility may be improved, especially for the visually impaired, by providing physical cues.
The EAP transducer may be configured to displace proportionally to an applied voltage, which facilitates programming of a control system used with the subject tactile feedback devices. For example, a software algorithm may convert pixel grayscale to EAP transducer displacement, whereby the pixel grayscale value under the tip of the screen cursor is continuously measured and translated into a proportional displacement by the EAP transducer. By moving a finger across the touchpad, one could feel or sense a rough 3D texture. A similar algorithm may be applied on a web page, where the border of an icon is fed back to the user as a bump in the page texture or a buzzing button upon moving a finger over the icon. To a normal user, this would provide an entirely new sensory experience while surfing the web, to the visually impaired this would add indispensable feedback.
EAP transducers are ideal for such applications for a number of reasons. For example, because of their light weight and minimal components, EAP transducers offer a very low profile and, as such, are ideal for use in sensory/haptic feedback applications.
As seen in
With a voltage applied, the transducer film 10 continues to deflect until mechanical forces balance the electrostatic forces driving the deflection. The mechanical forces include elastic restoring forces of the dielectric layer 12, the compliance or stretching of the electrodes 14, 16 and any external resistance provided by a device and/or load coupled to transducer 10. The resultant deflection of the transducer 10 as a result of the applied voltage may also depend on a number of other factors such as the dielectric constant of the elastomeric material and its size and stiffness. Removal of the voltage difference and the induced charge causes the reverse effects.
In some cases, the electrodes 14 and 16 may cover a limited portion of dielectric film 12 relative to the total area of the film. This may be done to prevent electrical breakdown around the edge of the dielectric or achieve customized deflections in certain portions thereof. Dielectric material outside an active area (the latter being a portion of the dielectric material having sufficient electrostatic force to enable deflection of that portion) may be caused to act as an external spring force on the active area during deflection. More specifically, material outside the active area may resist or enhance active area deflection by its contraction or expansion.
The dielectric film 12 may be pre-strained. The pre-strain improves conversion between electrical and mechanical energy, i.e., the pre-strain allows the dielectric film 12 to deflect more and provide greater mechanical work. Pre-strain of a film may be described as the change in dimension in a direction after pre-straining relative to the dimension in that direction before pre-straining. The pre-strain may comprise elastic deformation of the dielectric film and be formed, for example, by stretching the film in tension and fixing one or more of the edges while stretched. The pre-strain may be imposed at the boundaries of the film or for only a portion of the film and may be implemented by using a rigid frame or by stiffening a portion of the film.
The transducer structure of
In addition to the EAP films described above, sensory or haptic feedback user interface devices can include EAP transducers designed to produce lateral movement. For example, various components including, from top to bottom as illustrated in
With reference to
In fabricating transducer 20, elastic film is stretched and held in a pre-strained condition by two opposing rigid frame sides 8a, 8b. It has been observed that the pre-strain improves the dielectric strength of the polymer layer 26, thereby improving conversion between electrical and mechanical energy, i.e., the pre-strain allows the film to deflect more and provide greater mechanical work. Typically, the electrode material is applied after pre-straining the polymer layer, but may be applied beforehand. The two electrodes provided on the same side of layer 26, referred to herein as same-side electrode pairs, i.e., electrodes 32a and 34a on top side 26a of dielectric layer 26 (see
In the illustrated embodiment, each of the electrodes has a semi-circular configuration where the same-side electrode pairs define a substantially circular pattern for accommodating a centrally disposed, rigid output disc 20a, 20b on each side of dielectric layer 26. Discs 20a, 20b, the functions of which are discussed below, are secured to the centrally exposed outer surfaces 26a, 26b of polymer layer 26, thereby sandwiching layer 26 therebetween. The coupling between the discs and film may be mechanical or be provided by an adhesive bond. Generally, the discs 20a, 20b will be sized relative to the transducer frame 22a, 22b. More specifically, the ratio of the disc diameter to the inner annular diameter of the frame will be such so as to adequately distribute stress applied to transducer film 10. The greater the ratio of the disc diameter to the frame diameter, the greater the force of the feedback signal or movement but with a lower linear displacement of the disc. Alternately, the lower the ratio, the lower the output force and the greater the linear displacement.
Depending upon the electrode configurations, transducer 10 can be capable of functioning in either a single or a two-phase mode. In the manner configured, the mechanical displacement of the output component, i.e., the two coupled discs 20a and 20b, of the subject sensory feedback device described above is lateral rather than vertical. In other words, instead of the sensory feedback signal being a force in a direction perpendicular to the display surface 232 of the user interface and parallel to the input force (designated by arrow 60a in
When operating sensory/haptic feedback device 2 in single-phase mode, only one working pair of electrodes of actuator 30 would be activated at any one time. The single-phase operation of actuator 30 may be controlled using a single high voltage power supply. As the voltage applied to the single-selected working electrode pair is increased, the activated portion (one half) of the transducer film will expand, thereby moving the output disc 20 in-plane in the direction of the inactive portion of the transducer film.
To effect a greater displacement of the output member or component, and thus provide a greater sensory feedback signal to the user, actuator 30 is operated in a two-phase mode, i.e., activating both portions of the actuator simultaneously.
Various types of mechanisms may be employed to communicate the input force 60a from the user to effect the desired sensory feedback 60b (see
Another variation of the present invention involves the hermetic sealing of the EAP actuators to minimize any effects of humidity or moisture condensation that may occur on the EAP film. For the various embodiments described below, the EAP actuator is sealed in a barrier film substantially separately from the other components of the tactile feedback device. The barrier film or casing may be made of such as foil, which is preferably heat scaled or the like to minimize the leakage of moisture to within the sealed film. Portions of the barrier film or casing can be made of a compliant material to allow improved mechanical coupling of the actuator inside the casing to a point external to the casing. Each of these device embodiments enables coupling of the feedback motion of the actuator's output member to the contact surface of the user input surface, e.g., keypad, while minimizing any compromise in the hermetically sealed actuator package. Various exemplary means for coupling the motion of the actuator to the user interface contact surface are also provided. Regarding methodology, the subject methods may include each of the mechanical and/or activities associated with use of the devices described. As such, methodology implicit to the use of the devices described forms part of the invention. Other methods may focus on fabrication of such devices.
The transducer/actuator embodiments described thus far have the passive layer(s) coupled to both the active (i.e., areas including overlapping electrodes) and inactive regions of the EAP transducer film. Where the transducer/actuator has also employed a rigid output structure, that structure has been positioned over areas of the passive layers that reside above the active regions. Further, the active/activatable regions of these embodiments have been positioned centrally relative to the inactive regions. The present invention also includes other transducer/actuator configurations. For example, the passive layer(s) may cover only the active regions or only the inactive regions. Additionally, the inactive regions of the EAP film may be positioned centrally to the active regions.
Referring to
When a voltage difference is applied across the oppositely-charged electrodes 16a, 16b, the opposed electrodes attract each other thereby compressing the portion of the dielectric polymer layer 14 therebetween. As the electrodes 16a, 16b are pulled closer together (along the z-axis), the portion of the dielectric layer 14 between them becomes thinner as it expands in the planar directions (along the x- and y-axes). For incompressible polymers, i.e., those having a substantially constant volume under stress, or for otherwise compressible polymers in a frame or the like, this action causes the compliant dielectric material outside the active area (i.e., the area covered by the electrodes), particularly perimetrically about, i.e., immediately around, the edges of the active area, to be displaced or bulge out-of-plane in the thickness direction (orthogonal to the plane defined by the transducer film). This bulging produces dielectric surface features 24a-d. While out-of-plane surface features 24 are shown relatively local to the active area, the out-of-plane is not always localized as shown. In some cases, if the polymer is pre-strained, then the surface features 24a-b are distributed over a surface area of the inactive portion of the dielectric material.
In order to amplify the vertical profile and/or visibility of surface features of the subject transducers, an optional passive layer may be added to one or both sides of the transducer film structure where the passive layer covers all or a portion of the EAP film surface area. In the actuator embodiment of
In addition to the elevated polymer/passive layer surface features 26a-d, the EAP film 12 may be configured such that the one or both electrodes 16a, 16b are depressed below the thickness of the dielectric layer. As such, the depressed electrode or portion thereof provides an electrode surface feature upon actuation of the EAP film 12 and the resulting deflection of dielectric material 14. Electrodes 16a, 16c may be patterned or designed to produce customized transducer film surface features which may comprise polymer surface features, electrode surface features and/or passive layer surface features.
In the actuator embodiment 10 of
The EAP transducers of the present invention may have any suitable construct to provide the desired thickness mode actuation. For example, more than one EAP film layer may be used to fabricate the transducers for use in more complex applications, such as keyboard keys with integrated sensing capabilities where an additional EAP film layer may be employed as a capacitive sensor.
The actuators of the present invention may employ any suitable number of transducer layers, where the number of layers may be even or odd. In the latter construct, one or more common ground electrode and bus bar may be used. Additionally, where safety is less of an issue, the high voltage electrodes may be positioned on the outside of the transducer stack to better accommodate a particular application.
To be operational, actuator 30 must be electrically coupled to a source of power and control electronics (neither are shown). This may be accomplished by way of electrical tracing or wires on the actuator or on a PCB or a flex connector 62 which couples the high voltage and ground vias 68a, 68b to a power supply or an intermediate connection. Actuator 30 may be packaged in a protective barrier material to seal it from humidity and environmental contaminants. Here, the protective barrier includes top and bottom covers 60, 64 which are preferably sealed about PCB/flex connector 62 to protect the actuator from external forces and strains and/or environmental exposure. In some embodiments, the protective barrier maybe impermeable to provide a hermetic seal. The covers may have a somewhat rigid form to shield actuator 30 against physical damage or may be compliant to allow room for actuation displacement of the actuator 30. In one specific embodiment, the top cover 60 is made of formed foil and the bottom cover 64 is made of a compliant foil, or vice versa, with the two covers then heat-sealed to board/connector 62. Many other packaging materials such as metalized polymer films. PVDC, Aclar, styrenic or olefinic copolymers, polyesters and polyolefins can also be used. Compliant material is used to cover the output structure or structures, here bar 46b, which translate actuator output.
The conductive components/layers of the stacked actuator/transducer structures of the present invention, such as actuator 30 just described, are commonly coupled by way of electrical vias (68a and 68b in
Formation of the conductive vias of the type employed in actuator 30 of
Standard electrical wiring may be used in lieu of a PCB or flex connector to couple the actuator to the power supply and electronics. Various steps of forming the electrical vias and electrical connections to the power supply with such embodiments are illustrated in
The thickness mode EAP transducers of the present invention are usable in a variety of actuator applications with any suitable construct and surface feature presentation.
The button actuator may be in the form of a single input or contact surface or may be provided in an array format having a plurality of contact surfaces. When constructed in the form of arrays, the button transducers of
Those skilled in the art will appreciate that the thickness mode transducers of the present invention need not be symmetrical and may take on any construct and shape. The subject transducers may be used in any imaginable novelty application, such as the novelty hand device 140 illustrated in
The transducer film of the present invention may be efficiently mass produced, particularly where the transducer electrode pattern is uniform or repeating, by commonly used web-based manufacturing techniques. As shown in
Either prior to or after singulation, the strip or singulated strip portions, may be stacked with any number of other transducer film strips/strip portions to provide a multi-layer structure. The stacked structure may then be laminated and mechanically coupled, if so desired, to rigid mechanical components of the actuator, such an output bar or the like.
Other gasket-type actuators are disclosed in U.S. patent application Ser. No. 12/163,554, referenced above. These types of actuators are suitable for sensory (e.g., haptic or vibratory) feedback applications such as with touch sensor plates, touch pads and touch screens for application in handheld multimedia devices, medical instrumentation, kiosks or automotive instrument panels, toys and other novelty products, etc.
Touch screen device 190 of
The two touch screen devices just described are single phase devices as they function in a single direction. Two (or more) of the subject gasket-type actuators may be used in tandem to produce a two phase (bi-directional) touch screen device 200 as in
Performance may be enhanced by prestraining the dielectric film and/or the passive material. The actuator may be used as a key or button device and may be stacked or integrated with sensor devices such as membrane switches. The bottom output member or bottom electrode can be used to provide sufficient pressure to a membrane switch to complete the circuit or can complete the circuit directly if the bottom output member has a conductive layer. Multiple actuators can be used in arrays for applications such as keypads or keyboards.
The various dielectric elastomer and electrode materials disclosed in U.S. Patent Application Publication No. 2005/0157893 are suitable for use with the thickness mode transducers of the present invention. Generally, the dielectric elastomers include any substantially insulating, compliant polymer, such as silicone rubber and acrylic, that deforms in response to an electrostatic force or whose deformation results in a change in electric field. In designing or choosing an appropriate polymer, one may consider the optimal material, physical, and chemical properties. Such properties can be tailored by judicious selection of monomer (including any side chains), additives, degree of cross-linking, crystallinity, molecular weight, etc.
Electrodes described therein and suitable for use include structured electrodes comprising metal traces and charge distribution layers, textured electrodes, conductive greases such as carbon greases or silver greases, colloidal suspensions, high aspect ratio conductive materials such as conductive carbon black, carbon fibrils, carbon nanotubes, graphene and metal nanowires, and mixtures of ionically conductive materials. The electrodes may be made of a compliant material such as elastomer matrix containing carbon or other conductive particles. The present invention may also employ metal and semi-inflexible electrodes.
Exemplary passive layer materials for use in the subject transducers include but are not limited to silicone, styrenic or olefinic copolymer, polyurethane, acrylate, rubber, a soft polymer, a soft elastomer (gel), soft polymer foam, or a polymer/gel hybrid, for example. The relative elasticity and thickness of the passive layer(s) and dielectric layer are selected to achieve a desired output (e.g., the net thickness or thinness of the intended surface features), where that output response may be designed to be linear (e.g., the passive layer thickness is amplified proportionally to the that of the dielectric layer when activated) or non-linear (e.g., the passive and dielectric layers get thinner or thicker at varying rates).
Regarding methodology, the subject methods may include each of the mechanical and/or activities associated with use of the devices described. As such, methodology implicit to the use of the devices described forms part of the invention. Other methods may focus on fabrication of such devices.
As for other details of the present invention, materials and alternate related configurations may be employed as within the level of those with skill in the relevant art. The same may hold true with respect to method-based aspects of the invention in terms of additional acts as commonly or logically employed. In addition, though the invention has been described in reference to several examples, optionally incorporating various features, the invention is not to be limited to that which is described or indicated as contemplated with respect to each variation of the invention. Various changes may be made to the invention described and equivalents (whether recited herein or not included for the sake of some brevity) may be substituted without departing from the true spirit and scope of the invention. Any number of the individual parts or subassemblies shown may be integrated in their design. Such changes or others may be undertaken or guided by the principles of design for assembly.
In another variation, the cartridge assembly or actuator 360 can be suited for use in providing a haptic response in a vibrating button, key, touchpad, mouse, or other interface. In such an example, coupling of the actuator 360 employs a non-compressible output geometry. This variation provides an alternative from a bonded center constraint of an electroactive polymer diaphragm cartridge by using a non-compressible material molded into the output geometry.
In an electroactive polymer actuator with no center disc, actuation changes the condition of the Passive Film in the center of the electrode geometry, decreasing both the stress and the strain (force and displacement). This decrease occurs in all directions in the plane of the film, not just a single direction. Upon the discharge of the electroactive polymer, the Passive film then returns to an original stress and strain energy state. An electroactive polymer actuator can be constructed with a non-compressible material (one that has a substantially constant volume under stress). The actuator 360 is assembled with a non-compressible output pad 368a 368b bonded to the passive film area at the center of the actuator 360 in the inactive region 365, replacing the center disk. This configuration can be used to transfer energy by compressing the output pad at its interface with the passive portion 365. This swells the output pad 368a and 368b to create actuation in the direction orthogonal to the flat film. The non compressible geometry can be further enhanced by adding constraints to various surfaces to control the orientation of its change during actuation. For the above example, adding a non-compliant stiffener to constrain the top surface of the output pad prevents that surface from changing its dimension, focusing the geometry change to desired dimensions of the output pad.
The variation described above can also allow coupling of biaxial stress and strain state changes of electroactive polymer Dielectric Elastomer upon actuation; transfers actuation orthogonal to direction of actuation; design of non-compressible geometry to optimize performance. The variations described above can include various transducer platforms, including: diaphragm, planar, inertial drive, thickness mode, hybrid (combination of planar & thickness mode described in the attached disclosure), and even roll—for any haptic feedback (mice, controllers, screens, pads, buttons, keyboards, etc.) These variations might move a specific portion of the user contact surface, e.g. a touch screen, keypad, button or key cap, or move the entire device.
Different device implementations may require different EAP platforms. For example, in one example, strips of thickness mode actuators might provide out-of-plane motion for touch screens, hybrid or planar actuators to provide key click sensations for buttons on keyboards, or inertial drive designs to provide rumbler feedback in mice and controllers.
Housing assemblies can 264 and 266 can also be designed with integrated lips or extensions that cover the edges of the actuators to prevent electrical shock on handling. Any and all of these parts can also be integrated as part of the housing of a larger assembly such as the housing of a consumer electronic device. For example, although the illustrated housing is shown as a separate component that is to be secured within a user interface device, alternate variations of the transducer include housing assemblies that are integral or part of the housing of the actual user interface device. For instance, a body of a computer mouse can be configured to serve as the housing for the inertial transducer assembly.
The inertial mass 262 can also serve multiple functions. While it is shown as circular in
Filter Sound Drive Waveform for Electroactive Polymer Haptics
Another variation of the inventive methods and devices described herein involves driving the actuators in a manner to improve feedback. In one such example the haptic actuator is driven by a sound signal. Such a configuration eliminates the need for a separate processor to generate waveforms to produce different types of haptic sensations. Instead, haptic devices can employ one or more circuits to modify an existing audio signal into a modified haptic signal, e.g. filtering or amplifying different portions of the frequency spectrum. Therefore, the modified haptic signal then drives the actuator. In one example, the modified haptic signal drives the power supply to trigger the actuator to achieve different sensory effects. This approach has the advantages of being automatically correlated with and synchronized to any audio signal which can reinforce the feedback from the music or sound effects in a haptic device such as a gaming controller or handheld gaming console.
In another example, the circuit can include one or more rectifiers to filter the frequency of an audio signal to use all or a portion of an audio waveform of the audio signal to drive the haptic effect.
In another implementation, a threshold in the audio signal can be used to trigger the operation of a secondary circuit which drives the actuator. The threshold can be defined by the amplitude, the frequency, or a particular pattern in the audio signal. The secondary circuit can have a fixed response such as an oscillator circuit set to output a particular frequency or can have multiple responses based on multiple defined triggers. In some variations, the responses can be pre-determined based upon a particular trigger. In such a case, stored response signals can be provided in upon a particular trigger. In this manner, instead of modifying the source signal, the circuit triggers a pre-determined response depending upon one or more characteristics of the source signal. The secondary circuit can also include a timer to output a response of limited duration.
Many systems could benefit from the implementation of haptics with capabilities for sound, (e.g. computers, Smartphones, PDAs, electronic games). In this variation, filtered sound serves as the driving waveform for electroactive polymer haptics. The sound files normally used in these systems can be filtered to include only the optimal frequency ranges for the haptic feedback actuator designs.
Current systems operate at optimal frequencies of <200 Hz. A sound waveform, such as the sound of a shotgun blast, or the sound of a door closing, can be low pass filtered to allow only the frequencies from these sounds that are <200 Hz to be used. This filtered waveform is then supplied as the input waveform to the EPAM power supply that drives the haptic feedback actuator. If these examples were used in a gaming controller, the sound of the shotgun blast and the closing door would be simultaneous to the haptic feedback actuator, supplying an enriched experience to the game player.
In one variation use of an existing sound signal can allow for a method of producing a haptic effect in a user interface device simultaneously with the sound generated by the separately generated audio signal. For example, the method can include routing the audio signal to a filtering circuit; altering the audio signal to produce a haptic drive signal by filtering a range of frequencies below a predetermined frequency; and providing the haptic drive signal to a power supply coupled to an electroactive polymer transducer such that the power supply actuates the electroactive polymer transducer to drive the haptic effect simultaneously to the sound generated by the audio signal.
The method can further include driving the electroactive polymer transducer to simultaneously generate both a sound effect and a haptic response.
As for other details of the present invention, materials and alternate related configurations may be employed as within the level of those with skill in the relevant art. The same may hold true with respect to method-based aspects of the invention in terms of additional acts as commonly or logically employed. In addition, though the invention has been described in reference to several examples, optionally incorporating various features, the invention is not to be limited to that which is described or indicated as contemplated with respect to each variation of the invention. Various changes may be made to the invention described and equivalents (whether recited herein or not included for the sake of some brevity) may be substituted without departing from the true spirit and scope of the invention. Any number of the individual parts or subassemblies shown may be integrated in their design. Such changes or others may be undertaken or guided by the principles of design for assembly.
Also, it is contemplated that any optional feature of the inventive variations described may be set forth and claimed independently, or in combination with any one or more of the features described herein. Reference to a singular item, includes the possibility that there are plural of the same items present. More specifically, as used herein and in the appended claims, the singular forms “a,” “an,” “said,” and “the” include plural referents unless the specifically stated otherwise. In other words, use of the articles allow for “at least one” of the subject item in the description above as well as the claims below. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation. Without the use of such exclusive terminology, the term “comprising” in the claims shall allow for the inclusion of any additional element—irrespective of whether a given number of elements are enumerated in the claim, or the addition of a feature could be regarded as transforming the nature of an element set forth in the claims. Stated otherwise, unless specifically defined herein, all technical and scientific terms used herein are to be given as broad a commonly understood meaning as possible while maintaining claim validity.
In all, the breadth of the present invention is not to be limited by the examples provided. That being said, we claim:
The present application is a non-provisional of U.S. Provisional Application No. 61/111,316 filed Nov. 4, 2008 entitled “ELECTRO ACTIVE POLYMER TRANSDUCERS FOR HAPTIC FEEDBACK” and U.S. Provisional Application No. 61/111,319 filed Nov. 4, 2008 entitled “FILTER SOUND DRIVE WAVEFORM FOR EPAM HAPTICS AND EPAM ACTUATION PASSIVE FILM COUPLING” the entirety of which is incorporated by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US09/63307 | 11/4/2009 | WO | 00 | 7/29/2011 |
| Number | Date | Country | |
|---|---|---|---|
| 61111316 | Nov 2008 | US | |
| 61111329 | Nov 2008 | US |
