Abstract:
A key assembly includes a cover disposed over a transducer which is connected to a key acutator/interface disposed between the key transducer and a CPU. A tactile signal generator generates control signals from the CPU to activate the actuator/interface. The actuator/interface provides a signal appropriate to the particular transducer causing it to produce tactile feedback response to the key cover and user&#39;s touch. The key assembly may include a larger key cover disposed over a plurality of key transducers whereby the CPU causes texture and fine detail sensations variable over the key cover area by selective, variable actuation of the transducers. The end-user may thereby sense by physical contact with the large key cover electronically generated sensations of irregular surfaces or textures. Tactile profiles either user-specified or automatically invoked by a corresponding application vary the keyboard touch and feel as defined by the selected profile.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The field of the invention relates to user input devices for use with computer systems and electronic devices, and, more particularly to keyboards providing improved feedback to end-users. 
     2. Background and Related Art 
     One form of keyboard or keypad which has gained in popularity over the years employs a flat, thin, semi-rigid membrane, typically fashioned of plastic, which covers a single switch or switch matrix. Alpha numeric words, messages, or symbols such as “on”, “reset”, etc. are usually printed on the upper surface area of the membrane as desired to convey information to the end-user. Upon the user depressing the membrane over this message area contacts are thereby activated of a corresponding switch lying in vertical registry under the membrane and the message corresponding to the switch. 
     Because of their numerous benefits, such keyboards and keypads may be found in a wide variety of products, ranging from computer keyboards and calculators to test instrumentation, and even coffee makers and microwave ovens. These benefits include the fact that the switch contents may be hermetically sealed by the membrane from deleterious environmental factors such as coffee spills, foreign objects, dirt and dust, and the like. Additionally, the membrane is easily printed upon to convey the desired information to the user relative to each switch&#39;s function. Moreover, it is highly versatile, light, thin, flexible and therefore easily portable, readily cleaned, inexpensive, and has fewer moving parts than conventional key designs which can become quite complex and mechanically unreliable. 
     However, such membrane keyboards and keys are not without their own unique problems, not the least of which is the fact that such membrane keys or keyboards have little or no tactile feedback to the end user. This results in part from the fact that the throw of the key is oftentimes measured in terms of tenths or hundredths of an inch. It is thus often difficult for the user to determine whether in fact a key has been successfully depressed, rendering such things as touch typing extremely difficult and necessitating audible feedback in the form of annoying key closure beeps or the like. 
     Accordingly, an improvement was highly desired for such keys and keyboards which could provide this missing tactile and sensory feedback to the end-user. Such an improvement was desired which would not sacrifice the aforementioned compactness and portability afforded by such keys and keypads. 
     Still further, an improvement was desired which would permit the easy adjustment to match user preference or requirements in a given application of the amount of key resistance and distance of key travel which might be required. 
     In an effort to address this problem, some membrane keyboards were provided with domed membranes providing a small amount of additional key throw and feel. However users generally did not find this innovation to be particularly effective in terms of the touch, nor did it afford the end-user an opportunity to make any customized adjustments to the fed and touch of the keyboard. 
     Yet another problem associated with modern keys, keyboards, and keypads is that even when some form of tactile feedback is provided, it is generally discrete in the sense that it does not vary in terms of the qualitative or quantitative degree of feedback afforded to the end-user. For example, in a conventional computer keyboard, the user may feel a distinct click as a key is depressed. However, that is the only feedback provided to the end-user—a feedback which is singular in its type and magnitude, and with no latitude for the user being able to vary the type or magnitude of such feedback. This is not to diminish the importance of this more typical type of user feedback in keyboard art. Actually, manufacturers have taken great pains to design into computer keyboards for example, a highly distinctive click or feel. This is so important that computer manufacturers have actually built into computers sound generators which provide an audible artificial clicking sound upon depression of keys so as to create the illusion for an end-user that he or she is typing on a particular high quality keyboard with a virtual feel, as a result of this sound, different from the actual physical characteristics of the keyboard being employed. This psycho-acoustic affect has been employed with marginal results even in membrane keyboards for example wherein they are typically more devoid of any distinctive feel than are conventional keyboards. 
     Nevertheless, notwithstanding these attempts to improve keyboards, as aforementioned a need nevertheless existed to improve the tactile and sensory feedback to the end-user of such keys, keypads, and keyboards. Yet an additional weakness in conventional keyboard technology in affording user feedback was that such feedback was typically limited only to relatively small keys roughly the size of the human fingertip. This thereby significantly limited the ability to provide a distributed and more rich feedback over a wider area as afforded by the instant invention. 
     SUMMARY OF THE INVENTION 
     A key assembly includes a key cover disposed over a key transducer which, in turn, is connected to a key actuator/interface disposed between the key transducer and a computer system. A tactile signal generator generates control signals from a CPU to activate the actuator/interface. The actuator/interface serves two purposes. First, it provides an energy signal appropriate to the particular key transducer so as to cause the transducer to produce a desired tactile response or motion which it imparts to the key cover and user&#39;s touch. 
     Secondly, it provides an appropriate interface between the transducer and the CPU and tactile generator. The CPU may receive feedback of the user&#39;s interaction with the key cover by means of motion of the key cover imparting energy to the transducer, which is transferred through the actuator/interface to the CPU. The feedback loop between the end-user and the CPU is closed by means of the CPU generating the control signals to cause the tactile generator to in turn generate control signals imparted to the interface, thereafter to the transducer, and ultimately to the key cover. 
     In this manner, the CPU senses user interaction with the key assembly through the key cover and may generate appropriate key cover motion, resistance, and other tactile responses to be imparted to the end-user, either ab initio or in response to the feedback provided to the CPU from end-user interaction with the key assembly. In one embodiment, the key assembly includes a larger key cover disposed over a plurality of key transducers. In this manner, the CPU may cause the sensation of textures and fine detail variable over the area of the larger key assembly by means of selective and variable actuation of the various plural key transducers associated with the larger key cover. Thus, for example, the end-user may thereby sense by physical contact with the larger key cover an electronically generated sensation of an irregular surface or texture as desired. 
     The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings wherein like reference numbers represent like parts of the invention. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a pictorial illustration of a system employing the improved keyboard of the invention further detailed in FIGS. 2-7. 
     FIG. 2 is a functional block diagram further illustrating the system of FIG. 1 and a more detailed view of one of the keys in the keyboard of FIG.  1 . 
     FIG. 3 is a side view of a key assembly with improved tactile feedback in accordance with the invention. 
     FIG. 4 is side view of another key assembly with improved tactile feedback in accordance with the invention. 
     FIG. 5 is a side view of yet another key assembly with improved tactile feedback in accordance with the invention. 
     FIG. 6 is still another form of a key assembly with improved tactile feedback in accordance with the invention. 
     FIG. 7 is a side view of a key assembly of the invention wherein a larger tactile feedback area is provided. 
    
    
     DETAILED DESCRIPTION 
     Turning to FIG. 1, depicted therein is a system employing the keyboard with improved tactile feedback in accordance with the invention. A keyboard  10  is shown therein having a plurality of key assemblies  22 , a computer or CPU  14 , and a tactile generator  12  for purposes to be hereinafter detailed. The CPU  14  is connected to the tactile generator  12  by the connection  18  and the tactile generator in turn is connected to the keyboard  10  by means of connection  16 . In this manner signals may be generated by the CPU, transmitted to the tactile generator which in turn generates signals delivered to the keyboard for purposes to be hereinafter described on the link  16 . Feedback signals originating from the various key assemblies  22  may be provided back to the CPU  14 , thereby closing the feedback loop on the conductor  20 . A key assembly  42  is for purposes of completeness also shown in the keyboard assembly  10 , having a larger key surface area, again to be described in greater detail with reference to FIG.  7 . Whereas a keyboard  10  has been depicted in FIG. 1 having a plurality of key assemblies  22 , the invention is not intended to be so limited, and admits to applications wherein, for example, a single key assembly  22  in accordance with the invention is utilized. 
     In FIG. 2, a hybrid diagram is provided which includes a simplified side view of one of the key assemblies  22  of FIG. 1 in conjunction with a functional block diagram of additional components of the key system of the invention which include the actuator/interface  28 , tactile generator  12  and CPU  14  previously mentioned. 
     Directing attention to the key assembly  22  in more detail, each such key assembly is provided with a key cover  24  which may be of a membrane variety) which is functionally interconnected to a key transducer/actuator  26  which serves two purposes. First, the transducer  26  may impart motion as desired to the key cover  24 . Alternatively, the transducer will receive motion from the key cover  24  which will be translated by the transducer  26  into a signal delivered on line  30  to the interface  28 . The transducer may be activated by a signal on line  32  delivered to the transducer  26  which, in response, is energized and generates motion delivered to the key cover  24 . This two-way interaction between the transducer  26  and key cover  24  wherein motion is imparted from the key cover  24  to the transducer  26  and alternatively from the transducer  26  to the key cover  24  is shown by the bi-directional arrow  27 . It should be readily apparent that any alphanumeric, word, message, or symbol as desired may be disposed on the upper surface of the key assembly  24  so as to convey its function and purpose to the end-user. Moreover, it should further be readily apparent that the end-user will contact this upper surface of the key cover  24  by means of fingers, the palm of the hand, or the like so as to receive the sensory and tactile feedback from the invention as desired as well as to impart motion and thereby signals from the end-user to the system through the key cover  24  and transducer  26 . 
     Continuing with FIG. 2, the purpose of the transducer interface  28  is to translate signals from the tactile generator  12  delivered to the interface  28  on line  16  into appropriate signals on line  32  which may be responded to by the transducer  26  and, conversely, to translate incoming signals from the transducer  26  on line  30  to the interface  28  into an appropriate signal to be delivered on line  20  to the CPU  14 . It is a feature of the invention that it is not intended to be limited to any particular single form of transducer  26 , but rather the invention admits to various forms of transducers  26  as appropriate. Thus, the interface  28  is depicted in a generic fashion in FIG. 2 in terms of its function in interfacing between the transducer on the one hand and the tactile generator and CPU on the other hand. In other words, the particular form of this interface  28  will vary dependent upon the characteristics of the specific transducer  26  employed, whether it be a solenoid type, electromagnetic type, muscle wire type, pneumatic type or any other such transducer  26  to be hereinafter described in greater detail with reference to FIGS. 3-7, respectively. 
     Turning to FIG. 3 now, a particular form of such a key assembly  22  is depicted therein employing an electromagnetic solenoid  34  as one form of the transducer  26 . It will be noted that this solenoid  34  is interconnected to an interface  28  appropriate to the electromechanical characteristics of the solenoid  34  by means of the connections  30  and  32 . In operation a signal  16  from the tactile generator  12  will be transformed as appropriate by the interface  28  and delivered on lines  30 - 32  to the solenoid  34  so as to cause vertical motion of the solenoid which is thereby imparted to the key cover  24  and ultimately to the end-user in contact with the upper surface of the key cover  24 . In this manner, sensory and tactile feedback may be provided to the end-user in contact with the key cover  24  as desired in response to program control operating the CPU  14 . 
     However, in keeping with the bi-directional nature of the feedback of the keyboard system of the invention, it will be readily appreciated that the solenoid  34  may also operate as a receiver transducer, translating motion imparted by the end-user on the key cover to the solenoid  34 , which in turn will cause generation of signals on lines  30 - 32  to be delivered to the interface  28 . In this manner, response from the end-user such as a key depression may be sensed by the assembly of FIG. 3, delivered from the solenoid  34  through the interface  28  on line  20  to the CPU  14  for further processing. 
     FIG. 4 depicts an alternate embodiment of the key assembly of the invention. In this form, rather than a solenoid  34 , an electromagnet  36  is substituted. However, operation is similar to that of the embodiment of FIG. 3, namely that the interface  28  upon delivering appropriate signals on lines  30 - 32  to the electromagnetic assembly  36  will cause it, in turn, to impart motion as desired to the key cover  24 . Also, in like manner to the embodiment of FIG. 3, motion from the end-user imparted on the key cover  24  to the electromagnet assembly  36  will cause electrical signals on lines  30 - 32  generated by the assembly  36  to be delivered to the interface  28  and ultimately to the CPU  14  on line  20 . Again, because of the different electromechanical characteristics between a solenoid  34  and electromagnetic assembly  36 , it will be readily appreciated that the interface  28  of FIGS. 3 and 4 will differ as appropriate, but nevertheless will provide the same functional capability of interfacing a particular transducer  26  to the tactile generator  12  and CPU  14 . 
     Turning now to FIG. 5, depicted therein is yet a further alternate embodiment of the key assembly  22  of FIG.  2 . In this embodiment, a memory or “muscle” wire metal element  38  is employed to impart motion to and sense movement of the key cover  24 . Such metals have the property that they will change shape when a voltage is applied to them. Thus, by imparting a potential difference across the leads  30 - 32  by means of the actuator/interface  28 , the muscle wire element  38  may be caused to elongate or shorten, thereby imparting the desired upward or downward movement or key resistance or “touch” to the key cover  24 . 
     Referring now to FIG. 6, depicted therein is still a further alternate embodiment of the key assembly  22  of FIG.  2 . In this case, a pneumatic element  40  is provided into an air chamber defined by the walls of the key assembly  22 . In this embodiment, unlike the prior embodiments of FIGS. 3-5, actuation of the key cover  24  is by means of pneumatic pressure rather than due to electrical characteristics of the transducers  34 ,  36 ,  38 . As a result, in this case the actuator/interface  28  is a means for generating and sensing pneumatic pressure either conveyed to or from the chamber defined by the walls of the key assembly  22 . By altering the pressure from the actuator/interface delivered through the pneumatic element  40  into this chamber, the key cover  24  may be caused to deflect upwards or downwards as desired. Moreover, inasmuch as the interface  28  will also be adapted to sense pressure. end-user application of force on the key cover  24  will cause a correlative increase in pressure in the chamber conveyed by the element  40  to the interface  28  wherein it will be sensed and then conveyed as a key press or the like along line  20  to the CPU  14 . 
     Referring now back to FIG. 1, it will be noted that a larger key assembly  42  may be desirably also be disposed in the keyboard  10  or provided alone. As previously described, in some instances it may be desirable to provide a larger tactile or sensory feedback area than a conventional keyboard key for enabling the end-user to sense a larger area by touch—either by means of rubbing a finger about the upper surface area defined by the larger key assembly  42 , by placing multiple fingers on the key area or perhaps, even in some instances, a portion of the palm itself. 
     Turning to FIG. 7, a highly simplified representative cross-section of a such a larger key assembly  42  is depicted therein. The familiar key cover  24  is shown, which, as before, may be of a membrane type, as well as, in this instance, a plurality of muscle wire transducers  38  (as was shown in FIG.  5 ), as well as an actuator/interface  28 A, and the familiar connections  20  and  16  to and from the CPU  14  and tactile generator  12  of FIG. 2 as well as the multiple connections  30 A- 32 A,  30 B- 32 B, and  30 C- 32 C between the respective muscle wire transducers  38  and the interface  28 A. However, in this embodiment of FIG. 7 a few differences are exhibited. First, obviously the key cover  24  is of a larger surface area to permit greater interaction between it and the end-user. Moreover, a plurality of such muscle wire transducers  38  are shown. Although the illustration of FIG. 4 is merely a side view depicting three such transducers, it will be readily apparent that such individual transducers may be distributed as desired in any pattern of the area defined by the key cover  24 . The interface  28 A differs from those of the prior embodiments in that separate actuating and sensing mechanisms will be provided so as to permit alternatively the activation to or sensing from the respective transducers  38  independently of one another, so that motion imparted or sensed by each respective transducer will be independent of those of the other remaining transducers. In this manner, by selectively activating this plurality of transducers, various textures and feels may be simulated on the key cover  24  due to the multiple small tactile feedback areas. For example, by selectively activating certain of the transducers  38  in varying amplitudes and sequences, an irregular surface might be conveyed by the key cover  24  which may be flexible in the case of a membrane keyboard to thereby convey a rough or undulating surface or wave to the end-user. 
     It will be recalled that one of the benefits of a membrane keyboard is that it is very thin and can be rolled and folded, thereby becoming highly useful in portable keyboard applications. However., as also previously noted, one drawback to such keyboards is the lack of tactile feedback which can make touch typing difficult, for example. A feature of the embodiments of the key assemblies  22  shown in FIGS. 3-7 are that in an unactivated state, the key covers  24  may be caused in their ambient state to essentially lie flat with respect to the rest of the upper surface of the key assembly  10  of FIG. 1, thereby facilitating storage of the keyboard by rolling or folding it for example. In contrast, however, upon selective activation of the various transducers  26 , these key covers  24  may be caused to extend upwards from the upper surface of the keyboard  10  so as to appear more like a conventional keyboard with raised keys and key throw, and the tactile feedback of key depressions. Thus, for example, in the embodiment of FIG. 6, with flexible key covers  24 , a positive pressure exerted by the air transducer  40  will cause the key assembly to extend upwards in a dome shape so as to appear and feel more like conventional keys. However, upon reducing positive pressure in the chamber defined by the key assembly  22  in FIG. 6, these keys would thus become flat and in a condition so as to render the key assembly  10  in a thin, flat configuration suitable for storage by rolling, folding and the like wherein the keys would lie flat for storage. Obviously, activating the transducers of the other embodiments of FIGS. 3-5 as appropriate would, in like manner, present the key covers  24  in a more desirable configuration for interaction with the end-user wherein by activating the solenoid  34 , electromagnetic assembly  36 , or muscle wire transducer  38 , again these corresponding key covers  24  would be raised in a position for contact with the user&#39;s digits. 
     In addition to providing for raised key covers  24  and for sensing the user&#39;s key depressions, these transducers  26  and specific embodiments thereof shown as transducers  34 - 38  have yet another advantage, namely that the degree of force exerted by them on the key cover is selectively variable as desired, responsive to signals from the interface  28  which in turn is responsive to signals from the tactile generator  12 . In this manner, the user is able to selectively adjust the height of the keys, the key throw, and the predetermined amount of tactile resistance to keystroke based, for example, on the amount of air pressure delivered by the transducer  40 , the electromotive force delivered by the solenoid  34 , and the like. Thus, an additional benefit of the invention is to essentially provide for a customizable keypad or key assembly in terms of its mechanical characteristics and responsiveness to touch. An end-user might simply select a particular mechanical keyboard responsiveness profile designated to the CPU  14  which, in turn, would generate an appropriate signal  18  to the tactile generator  12  (FIG.  2 ), thereby changing the characteristics of the tactile generator  12  so as to generate the appropriate differing sets of signals  16  to the interface  28 . These differing sets of signals to the interface  28  would thereafter be utilized by the interface to generate corresponding differing sets of signals  32  to the particular transducers  26 , thereby selectively changing the tactile profile of the keyboard  10  as desired. 
     Moreover, in addition to manual profile selection or input from an end-user to the CPU  14  selecting a desirable keyboard profile, the CPU in the alternative may automatically select a profile which varies given the requirements of a particular application executing on the CPU  14 . Thus, if the end-user invokes a word processing program through CPU  14 , a keyboard profile would automatically be invoked to essentially place the keyboard  10  in a conventional keyboard mode with the tactile feedback associated with conventional keyboards. On the other hand, if the end-user was executing a different application such as one for selecting types of cloth, yet a different keyboard profile might automatically be invoked by the CPU  14 —one which, in particular, for example, might activate the larger key assembly  42  so as to enable the end-user to sense a “virtual” cloth surface on the upper surface of key assembly  42 , enabling the user to simulate the feel of the texture of various types of cloth. 
     As yet a further illustration of the versatility of the tactilely variable keyboard  10 , differences in amplitude or frequency of key movements. in another embodiment, would be employed to differentiate between differing types of events such as alarms or other system events. It should also be appreciated that although in the embodiment of FIG. 1, a key assembly  10  is shown with a plurality of such keys, the invention may equally be applicable to an instance wherein even a single key assembly  22  is desired on a piece of equipment. 
     It should be readily apparent that although four alternate embodiments of the transducer  26  of FIG. 2 have been shown, the invention is not intended to be so limited. Accordingly, other forms of imparting motion to and sensing motion from the key assembly  24  are contemplated by the invention which may be embodied in another species of the generic transducer  26  of FIG.  2 . 
     Similarly, with respect to FIG. 7, in the case of a larger key area  24  in plural transducers, although in this embodiment the muscle wire  38  form of transducers has been shown, this embodiment is not intended to be limited only to that particular type of transducer. Thus, for example, the invention contemplates substitution of other transducers  26  of FIG. 2 in the form of the key assembly  42  of FIG. 7 as desired and even various combinations of such differing transducers  26 , depending upon the application and desired characteristics of the keyboard  10 . 
     It will be understood from the foregoing description that various modifications and changes may be made in the preferred embodiment of the present invention without departing from its true spirit. It is intended that this description is for purposes of illustration only and should not be construed in a limiting sense. The scope of this invention should be limited only by the language of the following claims.