HK1081722A - Keypads with multi-function keys - Google Patents

Description

Keyboard with multifunctional keys

Technical Field

The present invention relates generally to keyboards for manual data entry, and more particularly to keyboards having separate keys, each key having a plurality of functions associated therewith.

Background

It would be desirable if a keyboard could be provided with a large number of outputs (e.g., numbers, letters, punctuation characters, predetermined operations, etc.) in a small space, and without excessive mechanical complexity, material or labor costs. It is desirable that each input is accompanied by a single, well-defined tactile feedback, and that each key can be easily and reliably manipulated with one human finger to provide the desired input. One of the most difficult aspects of keypad design is to provide "correct" tactile sensation. This seemingly simple task is well known in the industry as if one simply presses a key to pick a product and test it (for purchase), not thinking about it if the key does not have the "right" feel.

It is further desirable to configure each "traditional" key so that they can provide multiple outputs, preferably up to five outputs per key. By "conventional keys" is meant separate keys or key regions that are placed over the associated switch element such that when a key is depressed, the switch is closed. Typically these keys also have separate tactile feedback elements associated with them, some of which (e.g., polymer or metal key domes) also provide separate switching functions.

The layout and association of keys of some keyboards has been generally accepted as a standard. For example, a standard 12-key telephone keypad layout has established an association between numbers and letters, the letters "ABC" being associated with the number "2", the "PQRS" being associated with the number "7", and so on. Throughout the application of the present invention, a telephone keypad is used as an example of an application of the present invention. However, the technique is not necessarily limited to use in a telephone keypad, but may be applied to any keypad having keys with associated central functions (e.g., "numbers" of a telephone keypad) and auxiliary functions (e.g., letters of a telephone keypad). Any symbol, alphanumeric or otherwise may be used.

More background information on this latter arrangement may be found in U.S. patent application Ser. No. 60/379,241 filed on 5/10 2002 and U.S. patent application Ser. No. 60/401,175 filed on 5/8/2002, the contents of which are incorporated herein by reference.

Disclosure of Invention

The invention features a keyboard having an array of keys or key regions, each key or key region having a central function associated therewith and one or more auxiliary functions associated therewith. The center function is triggered by manually engaging (i.e., pressing or touching) a center region of the key, and each of the auxiliary functions is triggered by manually engaging an edge region (i.e., a region that is not the center) of the key.

In the preferred embodiment, the keyboard includes separate switches that are located below the associated keys and that when activated without any other input will produce an output related to the key center function. The switch may be any of the techniques known to those skilled in the art of keyboard design, such as a key dome switch. In addition, the keyboard includes an array of spaced finger position sensors, each responsive to the offset position of a finger activating a given key switch.

In some arrangements, the finger position sensors are placed between adjacent keys. When more than two functions per key are desired, it is preferred that each key has more than one adjacent position sensor, each sensor corresponding to a different key output. The sensors may be formed as a large array.

Detection of the separated finger position may be accomplished by different means, such as capacitive and reflective infrared techniques, although capacitive detection is preferred in the present invention.

In some embodiments, a single separate capacitive sensor is located equidistant between the conventional keys. By measuring absolute or relative capacitance changes, the system determines whether the user's finger is on the center of the key, or intentionally off-center. If the finger is off center, the system considers that the user intends to use an auxiliary function, which is preferably represented by a graphic off center from the selected key and in the direction in which the user places his finger. Since each sensor is fixed at the position of the keyboard, the intention of the user can be easily determined.

In some cases, the inclusion of small nodes between keys provides the user with a tactile reference to help the user place their finger correctly off center.

In some applications, multiple sensors are placed in each spaced area between adjacent keys. These sensors may be grouped by their function so that the system can determine the orientation of the user's finger relative to the key. When a key switch under a particular key is triggered, the system determines which of the plurality of functions associated with that key the user wants to perform based on the detected position of the finger relative to the center of the key.

Preferably each key is provided with a central graphical element corresponding to the key centre function. It is also preferred to distinguish each auxiliary function by a separate graphical element, which is marked either on the key or on the surface of the housing adjacent to the key.

The keypad may be in the form of a substrate that fits within a housing that defines apertures through which the individual keys protrude, or may be in the form of an exposed substrate.

According to another aspect of the invention, a method is provided for determining user input from a keyboard having a well-defined set of keys, each key extending from an aperture in a housing, each key having an underlying electrical switch. The method includes detecting activation of a switch corresponding to a key and detecting a position of a finger relative to a center region of the key corresponding to the activated switch based on signals from finger sensor arrays spaced apart from each other within the keyboard. Upon detecting a finger offset from a center region of the key, an output corresponding to an auxiliary function associated with the key is provided. Otherwise, an output corresponding to the central function associated with the key is provided.

In some cases, each key is labeled with a graphic corresponding to its central function and one or more graphics corresponding to its auxiliary functions. In other cases, each key is marked with a graphic corresponding to its central function, while the housing is marked with a graphic corresponding to the auxiliary function of the key.

By providing multiple functions per key, aspects of the present invention can reduce the keyboard space required to support a given number of functions without having to operate multiple keys for each added function. With appropriate graphics, each function of the multifunction key is made independent of the other, and it can be operated directly by intuition without a trained operator. In addition, these additional functions can be achieved without increasing the number of touch switches and tactile feedback elements. For example, where there are 12 separate keys in a conventional telephone keypad layout, with 12 switches and tactile elements associated therewith, including for example the ability to detect finger deflection to four separate quadrants of each key, a total of 60 outputs (i.e., 5 per key) can be achieved.

One advantage of these embodiments is that standard haptic feedback switch elements and tools can be utilized so that designers can benefit substantially from their years of experience, during which time they have provided users with special quality switch and haptic capabilities. Similarly, users can benefit from their haptic experiences from the sensations they desire to bring with a keyboard in general, and/or from the sensations they would bring with a particular brand quality standard.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

Drawings

Fig. 1 shows an exposed surface of a first keyboard.

Fig. 2 shows an exposed surface of a second keypad.

Figures 3 to 5 show alternative arrangements of sensors and switches which may be used in the two keypads shown.

Fig. 6 to 9 are cross-sectional views of the keyboard taken along lines 6, 7, 8, 9 of fig. 3, showing four alternative keyboard configurations.

Like reference symbols in the various drawings indicate like elements.

Detailed Description

Fig. 1 shows a telephone keypad with alphabetic and punctuation characters that can be output using the auxiliary function graphic 14. In this embodiment, the primary graphical character 10 is a number and is located in the center of the conventional key 12, while the secondary function graphics 14 (here shown as letters) are placed on the conventional key 12, top left, bottom left, top right and bottom right. With this arrangement, the system is able to determine not only the finger position relative to the four quadrants, but also the up, down, left, and right positions of the finger position through various combinations of the signals of the sensors 20. The location nodes 16 are positioned on the housing 18 approximately equidistant from adjacent keys and they are spaced around the perimeter to form a pattern of telephone keypads. The size of the alternative location nodes 16 is preferably small as long as it is felt, thereby providing the user with a tactile reference to help the user properly position their finger off-center. Regardless of whether the positional junction 16 is used, the interstitial sensor 20 is able to detect whether the user's finger is placed in the center of the conventional key 12, or if not, it indicates that the user's hand is placed pointing to that quadrant. For example, if the four sensors around the number "8" show the finger at the center of the key, the system gives an output "8" when the underlying switch 30 is activated. If the four sensors around the number "8" show the finger moving to the lower left of the key, the system gives an output "V" when the lower switch 30 is activated. In all cases the user is able to press a single key with one finger and get a single feedback. The purpose of the location node 16 is to assist the user in correctly locating their finger, indicating how far off-center the finger 25 should be placed, and thus ultimately determining an ancillary function that the user desires. The location nodes 16 may have various shapes, such as small dots, hillocks, or small circles.

Fig. 2 shows another embodiment in which graphics representing additional characters are located on the housing 18. This embodiment is substantially the same as the embodiment of fig. 1, although the finger position sensor has been omitted for clarity. Each auxiliary function graphic 14 associated with a switch 30 (and thus the main graphic character 10) is closest to the switch 30.

Fig. 3 shows an array of sensors 20 and switches 30. Each switch 30 is positioned under a conventional key of the keyboard. The switch 30 may be in the shape of a rubber dome, a polymer dome, or a metal dome, among others. In this embodiment, the switches 30 have independent addresses, and can be addressed using independent lines, an array, or multiple paths. More importantly, each sensor 20 is associated with a single gap region between the switches 30. Each sensor 20 may include a conductive plate that forms one side of a capacitance, while the other side of the capacitance is formed by the trigger finger. In addition, each sensor 20 may include two conductive plates that form two sides of an "open" capacitor, and the presence of finger detection places the two capacitors in series, creating parasitic effects. In another example, each sensor 20 is an intersection of two perpendicular grid lines of sense lines. There are many other techniques for detecting capacitance that are known in the art and may be found in various applications, such as touch-controlled elevator buttons.

To operate the keyboard to give the desired output, the user simply places his or her finger on the graphic corresponding to the desired output and then presses the associated key to activate the underlying switch. When it is detected that the switch has been activated, the system determines whether the user wants to activate the central function corresponding to the centrally placed graphic 10 or the auxiliary function corresponding to one of the peripheral graphics 14, based on whether the signal from the individual sensor 20 exceeds a given threshold or based on the signal level of the associated sensor. As an example of the former type, with reference to the embodiment of fig. 1, if the capacitance value measured by the sensor 20 located just between the button "8" and the button "+" (i.e. the sensor marked "n" in fig. 3) is greater than a predetermined threshold when the sensor 20 below the number "8" is triggered, then the system outputs the letter "V". As an example of the latter type, if the sensor 20 located just between the "8" and "x" buttons measures a much higher capacitance value than the other three sensors 20 located near the "8" when the sensor 20 below the number "8" is activated, the system outputs the letter "V". A particular algorithm may include removing (or subtracting) the signal from the sensor 20 located on the side opposite the intended auxiliary functional graphic 14. The switch 30 (and in particular the tactile feedback metal dome element of the switch 30) may be used as one side of the local capacitance.

Fig. 4 shows another embodiment of an array of sensors 20 and switches 30, wherein each switch 30 has a set of sensors 20 (labeled "a", "b", "c", "d") associated therewith, wherein each sensor of the set of sensors of each switch 30 has a sensor identical to that of the other switches 30. That is, all sensors 20 labeled "a" are electrically equivalent to each other, which in effect means that triggering the different sensors labeled "a" has no effect on the control algorithm. The same is true for the other three sets of sensors labeled "b", "c", "d". The result is that fewer connections to the controller are required, here only four connections are required. This embodiment requires more accurate simulation than the embodiment of fig. 3. The switch 30 (and in particular the tactile feedback metal dome element of the switch 30) may be used as one side of the local capacitance.

Fig. 5 shows a variation of the embodiment of fig. 4, in which different rows use different sets of sensors 20, and adjacent sensors 20 of the same row are grouped together. As shown in fig. 4, the same labeled sensors are electrically equivalent. In this case, however, instead of each gap area 21 between switches 30 comprising the same four electrical entities (sensors 20) being distinguishable only by the position within the gap area 21, as in the embodiment of fig. 4, the keys of adjacent rows have individual sensors 20, in other words, rows "1-2-3" and "7-8-9" both have corresponding sensors "a-b-c-d", and "4-5-6" and "# -0-" both have sensors "e-f-g-h". This reduces the requirements on the electronics and does not require a very precise distinction between the individual sensors 20 grouped in each gap region 21. For example, the two sensors 20 to the right of the number "5" are "g" and "a", but since it is not possible for the "a" type sensor 20 to be associated with the number "5", the control algorithm is able to correctly give an output corresponding to the combination of the switch "5" and the sensor "g", ignoring the situation in which the sensor "a" is simultaneously triggered when the switch "5" is triggered. The result is an easier criterion for capacitance measurement and for output generation. Such an arrangement also enables the system to monitor the increased measurements of the non-correlated sensors. Using the same example, when switch "5" is pressed, an increased signal is measured at sensor "a", which may mean that the user wants an output corresponding to the combination of switch "5" and sensor "g". By comparing the measurements of these relevant and non-relevant sensors (and knowing their relative positions and shapes), the system is able to better determine the orientation of the finger and the user's intent.

Referring to fig. 6, the sensor 20 is placed on a printed circuit board 22 under a keymat 24, and the keys 12 protrude from clearance holes in the relatively rigid housing 18. Also shown is a switch 30, which here is a metal dome. The interaction between the user's finger 25 and the key 12 is also shown, pressing at the off-center of the key 12 when the finger is in contact with the location node 16. Upon activation of the switch 30, the sensor 20 determines the position of the finger 25 relative to the key 12. Differential measurement between two sensors 20 located on either side of the key 12 is an effective way to determine the desired position of the user's finger 25. If the differential measurement exceeds a threshold limit, it is determined that the finger 25 is off-center, and the function to be triggered is identified using the auxiliary function graphic 14 located below the finger 25 and associated with the switch 30 at the moment of triggering.

In another alternative configuration, shown in fig. 7, the sensor 20 is placed on the underside of the keymat 24. Conductive vias (not shown) connect the array of sensors 20 to the printed circuit board 22. In another configuration shown in fig. 8, the sensor 20 is placed on the housing 18. The conductive vias connect the sensor 20 to the PCB 22. Fig. 9 shows another embodiment, using a resilient plastic, elastomer or composite material to integrally mold the housing 18 and key 12. The conductive vias connect the sensor 20 to the PCB 22. In fig. 6 to 9, the metal dome tactile feedback element 32 provides both tactile feedback and switch operation. In fig. 6 to 9, the tactile feedback element 32 is made of a stainless steel dome that is electrically integrated with the operation of the sensor 20 as a first side of the capacitance, wherein a second side of the capacitance is provided by the sensor 20.

Some embodiments of the invention have been described. It will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.

Claims (25)

1. A keyboard having an array of keys (12), each key having a central function associated therewith and one or more auxiliary functions associated therewith, the central function of each key being activated by manually engaging a central region of the key and each auxiliary function being activated by manually engaging a corresponding peripheral region of the key.

2. The keyboard of claim 1 including an array of spaced apart finger position sensors (20), each finger position sensor being responsive to an offset position of a finger actuating a switch (30) of at least one respective key (12).

3. The keyboard of claim 2 wherein the finger position sensors (20) are disposed between adjacent keys (12).

4. A keyboard according to claim 2 or 3, wherein each key (12) provides more than two functions, each key having more than one adjacent position sensor (20), each sensor corresponding to a different key output.

5. A keyboard as claimed in any one of claims 2 to 4, wherein the finger position sensor (20) detects finger position by virtue of a change in its capacitance.

6. A keyboard as claimed in any one of claims 2 to 5, wherein each finger position sensor (20) is located substantially equidistantly between a respective pair of keys (12).

7. The keyboard of any of claims 2 to 5 wherein the array of keys defines gap regions (21) between adjacent sets of four keys (12), each gap region containing two finger position sensors (20).

8. The keyboard of any of claims 2 to 5 wherein the array of keys defines gap regions (21) between adjacent sets of four keys (12), each gap region containing four finger position sensors (20).

9. A keyboard according to any preceding claim, wherein each key (12) is labelled with a centre graphic (10) corresponding to the centre function associated with that key.

10. A keyboard according to claim 9, wherein each key (12) is further labelled with an auxiliary graphic (14) corresponding to the key's associated auxiliary function.

11. A keyboard according to claim 9, adjacent each key (12) being labelled with an auxiliary graphic (14) and corresponding to the associated auxiliary function of that key.

12. A keyboard according to any preceding claim, comprising separate switches (30) located beneath the associated key (12) and which are triggered to produce an output associated with the key centre function in the absence of any other input.

13. The keyboard of claim 12, wherein the switch (30) comprises a key dome.

14. A keyboard as claimed in claim 12 or 13, wherein the auxiliary function is triggered by capacitively sensing finger position between a key switch (30) and an adjacent finger position sensor (20).

15. The keyboard of claim 14 wherein each switch (30) acts as a first side of a capacitance corresponding to an auxiliary function and each sensor (20) acts as a second side of a capacitance corresponding to an auxiliary function.

16. The keyboard of any preceding claim in the form of a keymat (24) fitted into a housing (18), the housing defining apertures through which respective keys (12) of the keymat project.

17. The keyboard of claim 16, wherein the sensor (20) is disposed on an underside of the housing (18) or on a surface of the keymat (24).

18. A keyboard as claimed in any preceding claim, for assisting a function.

19. The keypad of any of the above claims further comprising tactile elements (16) on the exposed surface of the keypad between the keys (12).

20. The keyboard of claim 19 wherein the tactile element comprises a nub (16) extending from an exposed surface of the keyboard.

21. A method of determining user input from a keyboard having a defined set of physical keys (12), each key projecting through an aperture in a housing (18), each key having an electrical switch (30) located below, the method comprising:

detecting activation of a switch (30) corresponding to a key (12);

detecting the position of a finger relative to the central region of the key (12) corresponding to the activated switch (12) based on signals from an array of finger detectors (20) spaced from each other in the keyboard;

an output corresponding to the auxiliary function associated with the key is provided upon detection of a finger position offset from a center region of the key, and an output corresponding to the center function associated with the key is provided otherwise.

22. A method according to claim 21, wherein each key is marked with a graphic (10) corresponding to the key center function and one or more graphics (14) corresponding to the key auxiliary functions.

23. A method according to claim 21, wherein each key (12) is marked with a graphic (10) corresponding to the key center function and the casing (18) is marked with a graphic (14) corresponding to the key auxiliary function.

24. A method according to any one of claims 20 to 22, wherein the keypad includes tactile elements (16) on the exposed surface of the keypad between the keys (12) to assist the user in locating the position of a finger relative to a given key.

25. A method according to any of claims 20 to 24, wherein each switch (30) acts as a first side of a capacitance corresponding to an auxiliary function and each sensor (20) acts as a second side of a capacitance corresponding to an auxiliary function.