GB2275799A

GB2275799A - Keyboards

Info

Publication number: GB2275799A
Application number: GB9304115A
Authority: GB
Inventors: Mark Jonathan Lewis
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-03-01
Filing date: 1993-03-01
Publication date: 1994-09-07
Also published as: GB9304115D0

Abstract

A key for a keyboard has a signal-responsive changeable display and may comprise a single display source for a plurality of the keys, each provided with optical means, e.g. fibre optics, to produce variable images from the source. A key display image may extend across a plurality of keys each operable to provide one and the same key function or graded functions, such image having the form of an enlarged character or a piano keyboard. Operation of a mode key can change the displays of a plurality of other keys. Key displays for keys that are not to be used may be blanked out, e.g. in answering a multiple choice question. The keyboard can be combined with a computer screen or can be used for a musical instrument.

Description

TITLE "KEYBOARDS" BACKGROUND This invention relates to keyboards, to keys suitable for use in keyboards, to software or other means to cooperate with keyboards, to computers comprising any of the foregoing, to outputs thereof, and to means for use in any of the foregoing or for independent use.

It is known for keys of typewriter and computer keyboards to have differing functions depending upon what may be called a "mode" action, effected beforehand or simultaneously with depression of the key concerned. For example, the mode key "shift" or "shift lock" on a typewriter can be operated simultaneously or beforehand, respectively, with a key to change the effect of pressing the key. With a computer keyboard, there are usually three mode keys, Shift, Ctrl, Alt (as well as Caps Lock) and these may be operated singly or multiply to change the effective action of a key. Further, computer programmes can automatically set the effective action (function) of a key, for example the so-called "function" keys or can allow them to be altered by the user to alter the functions of keys.

With a typewriter, the two different characters, e.g. upper case and lower case of a letter, are both printed on the face of the key for ready reference. On a computer, three, or possibly four, characters can appear on some keys. However, for the more unusual case of the function keys whose function cannot be described by a single character but only by a word, it is customary to provide a template which is to be located adjacent the set of function keys.

THE INVENTION The present inventor considers that the foregoing methods of marking keys or indicating their function is awkward and inconvenient and proposes, according to one aspect of the invention, as an improvement in this regard, a key as claimed in claim 1. This provides a further advantage in that the legends displayed on individual keys can also be controlled so as to be changed (varied or selected) in response to signals other than those produced by pressing mode keys, e.g. in response to a particular programme in the computer or in response to instructions keyed into the computer. The key may be provided with a plurality of different fixed displays, any one or more of which can be selected by supplying suitable signals to the key. On the other hand, it is much more advantageous if the key comprises a visual display unit (VDU) adapted to display a variable image, i.e.

different images which can (subject to content) be spread over the same area, according to signals supplied to the key, since these can be much larger and more varied than a plurality of fixed displays. That is to say that, while the whole face area of a key may be occupied by a plurality of fixed displays, each one of which may be selected by control signals, each occupying its own area of the key face, a display that is variable (in the sense just stated) can occupy the whole (or the major part) of the face of a key since the image on that display can be changed throughout its area, so that only one such display is needed for the key's face. Such a VDU may comprise an LCD (Liquid Crystal Display) screen or an LEP (Light-emitting Plastic, e.g.

polyphenylene vinylene, reference article headed "The cinema in your living room" by Chris Partridge on page 8 of the Business Section of the Sunday Times of 14 February 1993, published in London, England) screen. In between the LCD, the manufacturing techniques for which are well developed and which can therefore be made cheaply (and readily with current technology), and the LEP, which is still currently being developed but gives a much brighter image requiring far less driving power, comes the TFT (Thin Film Transistor) display screen currently used for portable computers. Instead of the "matrix" type of drive of the large LCD screen (in which a pixel is identified by two simultaneous signals applied one to a chosen position (terminal) along an "x" edge and one to a suitable position (terminal) along a "y" edge), the TFT screen has an electrical connection to each separate pixel. While this may be necessary for large screens, the LCD may be sufficient for a screen the size of a key face. There are also capacitative problems with a large screen, that would largely disappear with key-sized screens. Indeed, simple LCD screens are used for watch faces, having a separate electrical connection to each (non-pixel) display element and, in a simple key face according to the invention, it may be sufficient to have such an arrangement of LCD screen, having only 5 horizontally by 8 vertically pixels, as already found e.g. for each character of the display of fax machines. Other possible ways of providing the signal-responsive changeable display are discussed below.

The key may be adapted to display different images in response to respective input signals, i.e. the technology to display a particular image may be responsive to a particular input signal, which means that the different input signals can be very simple, e.g. on separate inputs of the key. Again, the key may be adapted to display different images in response to respective coded input signals, e.g. different voltages on a single input of the key or, for more reliability, different pulse codes. For example, the different signals may all be provided at a single input of the key but be provided in a coded series of equal pulses or in pulses having a coded profile. This may also enable the technology within the key to be made somewhat simpler. Again, the key may comprise a plurality of inputs and be adapted to display different images according to respective input signals supplied to respective said inputs and/or combinations of said inputs. This can make the technology within a key even simpler. Thus, each key may usefully comprise a decoder, or a decoder may be provided for a group, e.g. row or "column", of keys (the "columns" of keys are usually slanting or staggered). Pulse code technology is known and the necessary decoders may readily be adapted from e.g. electronic telephone exchange technology once the present requirement is perceived. The signals can comprise electrical signals, which is preferred for the output of a computer with present day technology, or may comprise pulses of or in fluid, pressure of mechanical members, magnetic or electromagnetic pulses and so on. The transmission and reception of such signals is known technology. An advantage of the magnetic and electromagnetic pulses (and of optical signals, as mentioned below,) is that this may allow the key to be physically separate from the signalling means.

Although the gap may be small, e.g. imam, an advantage of not having to fix the key directly to a source means for the signals is to make assembly of the keyboard (and repair of the same and/or replacement of its keys) much simpler. Each key may then only need to be connected to a power supply and to an outlet for the signal generated by depression of the key, and even these connections may be obviated. The term "depression" is used in the present specification to refer to any form of actuati-on of a key, even by finger proximity as described below. It may be appropriate for the display of a key to disappear when the key is depressed This can be effected readily with these embodiments having a separate key by arranging that the gap will then be too large to transmit the signal.

While, as mentioned, the key may comprise an LCD unit, it may alternatively or in addition be adapted for said signals to comprise optical signals, e.g. if the key comprises fibre optics, e.g. for transmitting these optical signals directly to a display area of the key. For example, the fibre optics can be used to form and/or magnify an optical signal from a source point to the display area.

It will be appreciated that the invention lends itself to conveying more information (or conveying information more interestingly or more usefully) if the key is adapted to display an image with controllable colour.

The foregoing can be adapted for use by the blind or for use in the dark if the key is adapted for said display to be tactile, e.g. in Braille. A particularly neat, economical and practical solution is for the key to have a flexible face member with one or more bubble areas adapted to expand temporarily in a direction away from the key under the influence of localised heating.

In accordance with the foregoing, another aspect of the invention comprises a keyboard as claimed in claim 15. This may have any of the above-described features. If the keyboard has the features of claim 17, and more particularly if it also has the features of claim 18, there is produced an arrangement of one or another matrix type which can be quite simple to operate and reasonably economical to manufacture.

A keyboard having the features of claim 19 can be particularly economical to manufacture, since the keys can be relatively simple in design, and can be relatively trouble-free if the keys, so far as they are movable, are not fixed to electrical means, which fixing upon repeated movement could be more prone to failure. Alternatively, the keyboard may be as claimed in claim 20, which may produce manufacturing and/or operating advantages in requiring smaller optical source means.

A particularly versatile keyboard may be provided having the features of claim 21. On the other hand, a keyboard having the features of claim 22, can have its own advantages, e.g. preventing dirt etc., penetrating into the keyboard. The sheet may be flexible for touch operation, e.g. giving the advantage of a tactile response for confirming operation, and/or may be contoured to have a distinct contour for each relevant key position, for the same purposes. Of course, the keyboard may comprise markings on the sheet and/or behind it, to distinguish respective key positions and/or at places where the display is not required, which can enhance operability of the keyboard.

Said sheet may be provided with transparent, electrically conductive portions and/or the keyboard may be adapted for said sheet to make an electrical contact upon being flexed at a key position, to facilitate operation thereof. It is also possible for the keyboard to be adapted to respond electrostatically to the presence of a finger at a key position, again providing enhanced operability, though this may not allow the provision of a tactile feedback to confirm operation of a key.

It will be appreciated that the invention particularly lends itself to providing a keyboard as claimed in claim 29, with the clear advantages that the general size of key display may be much increased and/or the actual operating area for any particular key function may be increased. This can be further facilitated by a keyboard as claimed in claim 30. Likewise, the effective shape of keys can be changed (and likewise the layout of the keyboard) if the keyboard is adapted for said across-extending key display image to have a particular form, e.g.

that of a piano keyboard.

A particularly useful keyboard is one as claimed in claim 32, since one can immediately see upon operating a mode key the effect that this has on a plurality of other keys. A keyboard as claimed in claim 33 has the advantage of reducing the choice of keys to operate, which can simplify operation of the keyboard and/or reduce distraction e.g.

in answering a multiple choice question.

With the versatility of a VDU, different kinds of display image, which may be more intricate, can be provided, e.g. with a keyboard as claimed in claim 34. From what has been said above, it will be apparent that a keyboard can be provided as claimed in claim 35 which can facilitate, for example, use of different arrangements of the usual Roman alphabet, e.g. for a person who is unable to learn the qwerty arrangement and requires the keys in a more alphabetical arrangement or, for example, for a person who requires an arrangement that can be operated more quickly than the usual qwerty arrangement. Further, particularly for people who require to use other alphabets, there can be provided a keyboard as claimed in claim 36. A keyboard as claimed in claim 37 can provide more information, or information that is easier to assimilate, than one that does not have this facility.

According to another aspect of the invention, there is provided means as claimed in claim 40. This can facilitate use of a keyboard as mentioned above and/or can extend the possible uses thereof, e.g. as claimed in any one or more of claims 41 to 49, with the above-mentioned advantages. Thus also, there can be provided, according to other aspects of the invention, a computer as claimed in claim 52 or claim 53, and/or computer output material, computer output signals or computer programming means or other software applying means, as claimed in any one or more of claims 56 to 58, again with the above-mentioned advantages. According to further aspects of the invention, there may be provided any novel and inventive feature or combination of features disclosed or implied herein.

The usefulness of the embodiments of the present invention can be seen simply by reference to, for example, the "User's Guide and Reference" manual for Microsoft MS-DOS (these are trade marks) Operating System version 5.0, published in 1991 by Microsoft Corporation (Document No. SY07661/20885-0391). This shows, in the Appendix, twenty different keyboard layouts (and this is only for Roman alphabets), all of which are currently in production and necessary for different languages. Embodiments of the present invention could do away with the need for all these different keyboards and simply provide one keyboard whose displays can be changed by suitable software, which is much easier and cheaper and more convenient to provide than a multiplicity of keyboards. It is to be noted that some keys display four different characters and these look very complicated. Further, the whole of the (right hand) "number pad" is operable in two modes, with shifting between them by means of the Num Lock mode key and most keys of the number pad can have two different functions, depending upon the operation of the Num Lock mode key and the particular software programme being used. It is easy to forget which mode is in use, in spite of the signal light that is normally located above the number pad. However, with embodiments of the present invention, these difficulties can be ameliorated since the display images on the key faces themselves can be changed automatically to correspond to the mode chosen by the Num Lock key. Further, a mode key such as Num Lock could cycle through a series of three (or perhaps even more) modes and the key display images can change accordingly, bearing in mind that the mode key simply provides a signal every time it is actuated and these signals are counted to control the mode of operation of the number pad, (with current keyboards, there are only two modes, counted as the equivalent of alternate "on" and "off" conditions.) A further mode key, which is unused in many programmes, is Scroll Lock.

While the foregoing allows a vast variety of different keyboard layouts, the particular layout of the keyboard or a part of it can immediately be seen from the display images of the various keys.

However, it would also be useful to have a descriptive display, e.g. at or above the top of the keyboard, or available on the screen of the computer either permanently or upon request, which describes in words the keyboard layout in use. Again, such a display may provide a listing of the different keyboard layouts available, or the more common ones of these, or a user-selected list of these. There may be a particular key on the keyboard which instantly (and preferably only temporarily) brings up onto the main screen of the computer such a listing. Such a key may usefully be arranged only to display such a listing for the duration of the period while the key remains depressed, similarly to the action of e.g. Shift, Ctrl or Alt keys.

DESCRIPTION RELATING TO THE DRAWINGS Reference will now be made by way of example to the accompanying drawings, in which: Figure 1 is a diagrammatic plan view of a key embodying the invention and comprising four fixed display areas; Figure 2 is a diagrammatic plan view of a key comprising a single variable display area; Figure 3 is a diagrammatic analytical plan view of a key comprising a decoder; Figure 4 is a diagrammatic vertical cross-section of a key comprising optical fibres; Figure 5 is a diagrammatic plan view of a keyboard embodying the invention; Figure 6 is a diagrammatic plan view of a series of keys, illustrating one form of wiring together of the same; Figure 7 is a diagrammatic plan view of a series of keys, illustrating another form of wiring together of the same; Figure 8 is a diagrammatic vertical cross-section of a series of different keys illustrating different optical means for producing their display images; Figure 9 is a diagrammatic vertical cross-section of part of a transparent sheet keyboard; Figure 10 is a diagrammatic vertical cross-section of another form of a transparent sheet keyboard; Figure 11 is a diagrammatic vertical cross-section of yet another form of transparent sheet keyboard; Figure 12 is a diagrammatic plan view of a keyboard with a key display image having the form of a piano keyboard; Figure 13 is a diagrammatic plan view of a keyboard with a different arrangement for a key display image to have the form of a piano keyboard; Figure 14 is a plan view of a key face, showing its display image in the form of an icon; Figure 15 is a diagrammatic plan view of a computer and keyboard with various output arrangements; Figure 16 is a diagrammatic plan view of a key face adapted for said display to be tactile; and Figure 17 is a diagrammatic cross-section of the Figure 16 embodiment of the invention.

Referring to the drawings, like numerals in the different Figures refer to like items. A key 10 for a keyboard is provided with a signal-responsive changeable display 12 comprising a visual display unit 14 adapted to display different fixed images 16, 18, 20 in response to signals supplied thereto at respective inputs 22. Each fixed display 16, 18, 20 can be illuminated in response to the relevant signal, or alternatively the fixed displays can be responsive to coded signals if a decoder 34 is interposed. However, a much more useful and versatile arrangement is obtained if the display is variable, as illustrated in Figure 2, in which different elements 24 of a VDU 26 can be selected to compose a display image, which is variable according to the selection made, so that one, or usually more, of the elements 24 provide constituents of more than one different image. The VDU 26 is of a matrix type and a given element 24 thereof is selected by means of selecting for simultaneous input signals a particular wire of set 28 of "y" wires and a particular wire of set 30 of "x" wires. The term "wire" used herein refers to any suitable form of electrical conductor.

It is known technology to operate an LCD VDU in this manner and further details need not be given here. Thus, different images are displayed in response to respective input signals on wires 28, 30. The term "signals" includes groups of simultaneous signals on different wires and includes series of signals on common wires. As illustrated in Figure 3, different images can be displayed in response to respective coded input signals provided at an input wire 32 which passes to a decoder 34 which operates a key display 12 via sets of inputs 28, 30.

The plurality of inputs 28, 30 thus control display of different images according to respective input signals supplied to respective said inputs 28, 30 and/or combinations of said inputs 28, 30. The foregoing has been described particularly in relation to the signals comprising electric signals and the VDU 14 comprising an LCD unit of matrix type but can readily be adapted to other embodiments.

It is also possible for said signals to comprise optical signals.

As illustrated in Figure 4, signals provided at an input 36 operate an image source unit 38, each element 40 of which is connected by a set of optical fibres 42 to appropriate points 44 on the face 46 of the key 10. Each element 40 may control its own pixel 44, or one element 40 may provide a complete image spread over the face 46, in which case each element controls one image, or each element 40 may control a line (or part of a line) of points 44, the whole image on face 46 being composed of the appropriate points 44 of a series of such lines. In the latter case, there will be a large number of elements 40, preferably spread over two dimensions of unit 38 which will have the form of a sheet and of which at least one element 40 will require operation for each line (or part line) on face 46. In the case of each element controlling a complete image, there will only be a single series of elements 40 and these may be arranged in a line or throughout an area of unit 38. The signals on input 36 may be optical or electrical and, if coded, may require the interposition of a decoder 34.

A keyboard 50 comprises a plurality of keys 10, and the one illustrated in Figure 5 is, by way of example, shown as what is known as an "enhanced BIOS" keyboard. The keyboard 50 may comprise a plurality of keys 10, e.g. keys 52, 54, 56 and so on, each one (e.g.

52) comprising first 28 and second 30 sets of inputs and a matrix arrangement of pixel elements 24 individually operable in response to two coordinate signals, of which one said coordinate signal is supplied to the appertaining input/s of said first set 28 and the other said coordinate signal is supplied to the appertaining input/s of said second set 30, as described above, the inputs of said first set 28 of that one key 52 being interconnected with the corresponding inputs of said first set 28 of each other 54, 56 and so on, of said plurality of keys. Thus, as seen in Figure 2, the bottom wire of set 28 of key 52 is connected to the bottom wire of set 28 of key 54, and so on, and the next wire of set 28 of key 52 is connected to the next wire of set 28 of key 54 and so on, and this continues for all of the wires of set 28 of all of the keys 52, 54, 56 and so on. The wires of sets 30 are individual to each key and among all the keys, so that selection of a particular wire among sets 30 can only cause operation of one or more pixel elements in one column of one of the keys 52, 54, 56 and so on.

A more economical arrangement is obtained if the inputs of said second set 30 of said one key 52 are likewise interconnected with the corresponding inputs of said second set 30 of each of said other keys 54, 56 and so on and each key 52, 54, 56 and so on comprises at least one third input 58 which can be used to select that key.

Keyboard 50 may comprise a single display source 38, Figure 8, for a plurality of said keys 10, which keys comprise optical means 60, 62, 64 for displaying an image from said source 38. As illustrated diagrammatically in Figure 8, said optical means may comprise a single lens 60, a set of lenticules 62, or a set of optical fibres 64. Source 38 may be divided into or replaced by a set of individual display sources 66, one for each one of a plurality of said keys 10, each of which keys comprises optical means 60, 62, 64 for displaying an image from its said source 66. Again, each source 66 may be within the key structure as indicated in Figure 4.

It is to be understood that each key 10 described above is provided with appropriate signal-producing means 68 (illustrated only diagrammatically in Figure 8) arranged to produce a signal upon depression of its key 10. This can be provided by standard technology and need not be described here in further detail. Instead, there may be provided a transparent sheet 70 operable at the position 72, 74, 76 and so on of each of a plurality of the keys to provide a key function and thus an effective key at that position. As illustrated in Figure 9, said sheet 70 is flexible for touch operation so that, when a portion (e.g. 74) of it is depressed, it will make an electrical contact between transparent conducting portions 78, 80 and hence produce a suitable output signal. To facilitate the tactile friendliness of the board, each sheet 70, Figure 10, may be contoured to have a distinct contour (like a swelling or pimple) for each relevant key position 72, 74, 76 and so on. As further shown in Figure 10, there may be provided markings 82 on the sheet and/or markings 84 behind the sheet, e.g. on the face of unit 38, to distinguish respective key positions 72, 74, 76 and so on. Transparent sheet 70 constitutes a flexible printed circuit provided with transparent electrically conductive portions 78 which are exposed at key positions where they have to make contact with transparent electrically conductive portions 80 but are elsewhere insulated, e.g. from such positions to an edge connector of sheet 70. Thus, if the sheet is pressed elsewhere than at a key position, there will not be a spurious contact. Likewise, leads from these key positions to the edge connector can cross through depressible areas of others of these key positions for convenience, being insulated thereat and thus not giving rise to spurious signals upon depression of the sheet thereat. Apart from the electrical contacts made by said sheet upon being flexed at such key positions, as just described, the sheet 70 may be provided on its rear surface (or the source 38 on its front surface) with pairs of electrical terminals 86, 88, Figure 11, each adapted to respond electrostatically to the proximity of a finger at the corresponding key position 72, 74, 76 and so on. It is generally preferred not to have the pairs of terminals 86, 88 on the front surface, both in order to protect them from damage and to avoid any spurious signals that might be generated by actual contact between a finger and these pairs of terminals. (It is also possible to have them on the front surface and bridgable by touching to actuate a Hkey" but with current technology this is likely to produce inconsistent operation.) However, on some occasions, such pairs of terminals may be laid directly on the front surface of source 38 and simply covered with a thin layer of protective material in the nature of a varnish, so that effectively the keyboard becomes a VDU screen with defined areas acting as keys and arranged for each such area to have an image relating to the function of that key, as described above. Such a keyboard differs from previous touchsensitive screens in any one or more of the following: it is a keyboard, it is substantially horizontal, the image is intended to remain (in most cases) after operation of the key (i.e. except when the key display image is being arbitrarily changed by the user), each key is intended to provide a key-type input to the computer, each key is intended for repeated use, and so on. It is nevertheless possible to extend the keyboard 50 just described to an area 90, Figure 15, of it which is not intended to serve as a keyboard but as the main VDU of the computer 92. Again, it is possible for a structure such as unit 38 shown in Figure 11 to extend over the whole area 50, 90 and combine the functions of keyboard 50 and VDU 90, so that it is only a matter of showing in an appropriate portion of the "screen" area 50, 90 of unit 38 a keyboard 50 and, indeed, this can be moved to any position at will over the whole area 50, 90; and/or portions of what is usually the VDU area 90 may on particular occasions be made into one or more keyboards or miniature keyboards 50. However, it is contemplated that this will be too expensive for normal manufacture since it involves all the paraphernalia of keyboard key positions being provided throughout the whole of the VDU display area. One problem that needs to be dealt with carefully in any embodiment (e.g. that illustrated in Figure 11) that does not have moving parts, is to prevent unwanted multiple signals being generated upon key position "depression". Both the equivalent of spurious contact "chatter" and timing to determine when continued depression is to be interpreted as multiple depression, can be controlled by suitable pulse shaping and timing circuitry.

As explained above, embodiments Of the invention lend themselves to the keyboard being adapted for a key display image to extend across a plurality 94 or 96, Figure 5, of keys 10, each key 10 of that plurality being operable to provide one and the same key function. For example, the set-of keys in all the columns marked 94 provide an image of an upper case Y and if any one of these keys 94 is pressed there is a "Yes" response. Likewise, the across-extending key display image on keys 96 has the form of an enlarged upper case character N, and depression of any of keys 96 will produce a "No" response.

Said across-extending key display image may again have the form of a piano keyboard 98, Figure 12, and depression of any of the keys on one "note" of the piano keyboard image will produce one and the same output signal, e.g. to "type" that note on a stave on the main VDU screen of the computer. (Other keys 10 can be used simultaneously or sequentially to determine the length in time of the note and accordingly the shape of the representation on the main VDU screen.) Other keys may be used to determine loudness of each note, which can be coded onto the main VDU screen and later edited into conventional loudne answering a multiple choice question. For example, when a question occurs that requires the "Y" key to be pressed for "Yes" and the "N" key to be depressed for "No" but no other key, the software may at that point blank out all keys (or at least all keys of the main typing section of the keyboard) except the "Y" key and the "N" key, as indicated for convenience in Figure 5 (disregarding the enlarged characters). As seen in Figure 14, the keyboard may be adapted to provide at least one icon 102 for at least one key display image. Such icons would replace (or supplement) those shown on the screen in programmes such as Windows (Trade Mark). Depressing a special key or a special sequence of keys (e.g. dictated by software) can also be used to switch the key display images to a different arrangement from the usual qwerty arrangement and/or back and/or to a different alphabet from the usual Roman alphabet and/or back, e.g. Cyrillic, Hebrew or Arabic. Again, the keyboard can be adapted to provide a key display image with controllable, or simply selectable, colour/s.

Having become acquainted with the principles set forth above and below, the reader of normal skill will be able to make or adapt suitable software and circuitry to give effect to these principles.

A keyboard 50, as exemplified in Figure 5, can be provided internally or externally with suitable driver means, software means, programming means or other means 104 adapted to cooperate with the keyboard 50 to drive, control, programme or otherwise cause the same to provide keys 10 thereof with signal-responsive changeable display images, e.g. for any of the purposes and in accordance with any of the embodiments set forth above.

The computer 92 can have a signal output 106, or output means 108 (e.g. a printer or tape drive) producing output material 110, e.g. in the form of printed matter, or even computer programming means or other software applying means 112, e.g. in the form of a floppy disk, having the benefit of the invention and perhaps even comprising special signals indicative of the operation of the invention, e.g. for controlling other computers, whether separate or on a network.

As mentioned above, the keyboard 50 may comprise display windows 114 for indicating the current status of the key display images and/or lists of possible configurations of the display images of the keyboard 50 and/or otherwise.

As shown in Figures 16 and 17, a key 10 may have a set of pimplelike bubble areas 120 in an array of 5 x 8, these being formed in a flexible face member 70 and being adapted to expand temporarily in a direction away from the key, i.e. vertically up as seen in Figure 17, under the influence of localised heating from heating sources 122, in a direction away from the key (to a position 124) which are located one in each bubble area 120 and may be located on a rear display member 38, so that one and the same key 10 can be used by a sighted person and a blind person. The method of operation is known from bubble-jet technology with the main difference that the heating has to be maintained in order to maintain the, e.g. Braille, display on a key face.

The invention may further be applied to the array of keys on the front of a rack mount unit, such as is used with digital processing of sound, e.g. synthesisers or effects boxes. Such a unit is mounted in a rack and is accessible for control purposes only at a front face of the unit which comprises a "keyboard" in the form of a linear array of keys (if not in the more conventional arrangement of a plurality of rows, each row comprising a plurality of keys). The control of such units is particularly complex because each key may cycle through a large number (perhaps ten) different functions upon successive depressions of the key. Each key can affect each other and very complicated series of key depressions can be required for particular effects from the unit. Also, such a key could be used alone instead of in a keyboard. The advantage of applying the invention to such keys and keyboards is that the display is more directly and readily interpretable or recognisable. It can also be applied to keyboards (and single keys) that are used for other types of control panel, e.g.

a remote video or television control unit, a video recorder or television set itself, or a car dashboard. Further variations and applications will be apparent to one skilled in the art.

It will be apparent to one skilled in the art that features can be combined from different embodiments, both those described with reference to the drawings and those earlier described herein, and some features or combinations of features may have usefulness independently of the context in which they are described. Accordingly, the invention extends to all such novel and unobvious embodiments, features and/or combinations of features.

Claims

1. A key for a keyboard, characterised in that the key is provided with a signal-responsive changeable display.

2. A key as claimed in claim 1, characterised in that it is adapted to display different images in response to signals supplied thereto at respective inputs.

3. A key as claimed in claim 1, characterised in that the key comprises a visual display unit adapted to display a variable image in response to signals supplied thereto.

4. A key as claimed in any one of claims 1 to 3, characterised in that it is adapted to display different images in response to respective coded input signals.

5. A key as claimed in any one of claims 1 to 4, characterised in that it comprises a plurality of inputs and is adapted to display different images according to respective input signals supplied to respective said inputs and/or combinations of said inputs.

6. A key as claimed in any one of claims 1 to 5, characterised in that it is adapted for said signals to comprise electrical signals.

7. A key as claimed in claim 6, characterised in that it comprises a liquid crystal display unit.

8. A key as claimed in any one of claims 1 to 7, characterised in that it is adapted for said signals to comprise optical signals.

9. A key as claimed in claim 8, characterised in that it comprises fibre optics.

10. A key as claimed in any one of claims 1 to 9, characterised in that it is adapted to display an image with controllable colour.

11. A key as claimed in any one of claims 1 to 10, characterised in that it is adapted for said display to be tactile, e.g. in Braille.

12. A key as claimed in claim 11, characterised in that it has a flexible face member with one or more bubble areas adapted to expand temporarily in a direction away from the key under the influence of localised heating.

13. A key for a keyboard, substantially according to any example hereinbefore described.

14. A key for a keyboard, substantially according to any example hereinbefore described with reference to and illustrated in the accompanying drawings.

15. A keyboard, characterised in that it is adapted for at least one key thereof to be provided with a signal-responsive changeable display image.

16. A keyboard as claimed in claim 15, characterised in that it comprises one or more keys as claimed in any one of claims 1 to 14.

17. A keyboard as claimed in claim 15 or 16, characterised in that it comprises a plurality of keys, each one comprising first and second sets of inputs and a matrix arrangement of pixels individually operable in response to two coordinate signals, of which one said coordinate signal is supplied to the appertaining input/s of said first set and the other said coordinate signal is supplied to the appertaining input/s of said second set, the inputs of said first set of that one key being interconnected with the corresponding inputs of said first set of each other of said plurality of keys.

18. A keyboard as claimed in claim 17, characterised in that the inputs of said second set of said one key are interconnected with the corresponding inputs of said second set of each of said other keys and each key comprises at least one third input to select that key.

19. A keyboard as claimed in any one of claims 15 to 18, characterised in that it comprises a single display source for a plurality of said keys, which keys comprise optical means for displaying an image from said source.

20. A keyboard as claimed in any one of claims 15 to 18, characterised in that it comprises a display source for each one of a plurality of said keys, each of which keys comprises optical means for displaying an image from said source.

21. A keyboard as claimed in claim 19 or 20, characterised in that said optical means comprise fibre optics means.

22. A keyboard as claimed in any one of claims 19 to 21, characterised in that said optical means comprise a transparent sheet operable at the position of each of a plurality of the keys to provide a key function and thus an effective key thereat.

23. A keyboard as claimed in claim 22, characterised in that said sheet is flexible for touch operation.

24. A keyboard as claimed in claim 22 or 23, characterised in that said sheet is contoured to have a distinct contour for each relevant key position.

25. A keyboard as claimed in any one of claims 22 to 24, characterised in that it comprises markings on the sheet and/or behind it to distinguish respective key positions.

26. A keyboard as claimed in any one of claims 22 to 25, characterised in that said sheet is provided with transparent electrically conductive portions.

27. A keyboard as claimed in any one of claims 22 to 26, characterised in that it Is adapted for said sheet to make an electrical contact upon being flexed at a key position.

28. A keyboard as claimed in any one of claims 15 to 27, characterised in that it is adapted to respond electrostatically to the presence of a finger at a key position.

29. A keyboard as claimed in any one of claims 15 to 28, characterised in that it is adapted for a key display image to extend across a plurality of keys each operable to provide one and the same key function.

30. A keyboard as claimed in claim 29, characterised in that it is adapted for said across extending key display image to have the form of an enlarged character.

31. A keyboard as claimed in any one of claims 15 to 30, characterised in that it is adapted for said across extending key display image to have the form of a piano keyboard.

32. A keyboard as claimed in any one of claims 15 to 31, characterised in that it is adapted for operation of a mode key (e.g.

shift, caps lock, ctrl or alt key) to change the displays of a plurality of other keys.

33. A keyboard as claimed in any one of claims 15 to 32, characterised in that it is adapted to blank out key displays for keys that are not to be used, e.g. in answering a multiple choice question.

34. A keyboard as claimed in any one of claims 15 to 33, characterised in that it is adapted to provide at least one icon for at least one key display image.

35. A keyboard as claimed in any one of claims 15 to 34, characterised in that it is adapted to switch the key display images to a different arrangement from the usual qwerty arrangement and/or back.

36. A keyboard as claimed in any one of claims 15 to 35, characterised in that it is adapted to switch the key display images to a different alphabet from the usual Roman alphabet and/or back.

37. A keyboard as claimed in any one of claims 15 to 36, characterised in that it is adapted to provide a key display image with controllable colour.

38. A keyboard, substantially according to any example hereinbefore described.

39. A keyboard, substantially according to any example hereinbefore described with reference to and illustrated in the accompanying drawings.

40. Driver means, software means, programming means or other means, characterised in that it is adapted to cooperate with a suitable keyboard to drive, control, programme or otherwise cause the same to provide keys thereof with signal-responsive changeable display images.

41. Means as claimed in claim 40, characterised in that it is adapted to cause a said key display image to extend across a plurality of said keys each operable to provide one and the same key function.

42. Means as claimed in claim 41, characterised in that it is adapted to cause said across-extending key display image to have the form of an enlarged character.

43. Means as claimed in any one of claims 40 to 42, characterised in that it is adapted to cause said across-extending key display image to have the form of a piano keyboard.

44. Means as claimed in any one of claims 40 to 43, characterised in that it is adapted to respond to operation of a mode key (e.g. shift, caps lock, ctrl or alt key) to change the displays of a plurality of other keys.

45. Means as claimed in any one of claims 40 to 44, characterised in that it is adapted to blank out key displays for keys that are not to be used, e.g. in answering a multiple choice question.

46. Means as claimed in any one of claims 40 to 45, characterised in that it is adapted to provide at least one icon for at least one key display image.

47. Means as claimed in any one of claims 40 to 46, characterised in that it is adapted to switch the key display images to a different arrangement from the usual qwerty arrangement and/or back.

48. Means as claimed in any one of claims 40 to 47, characterised in that it is adapted to switch the key display images to a different alphabet from the usual Roman alphabet and/or back.

49. Means as claimed in any one of claims 40 to 48, characterised in that it is adapted to provide a key display image with controllable colour.

50. Driver means, software means, programming means or other means, substantially according to any example hereinbefore described.

51. Driver means, software means, programming means or other means, substantially according to any example hereinbefore described with reference to and illustrated in the accompanying drawings.

52. A computer, characterised in that it comprises signal-responsive changeable key display image means.

53. A computer as claimed in claim 52, characterised in that it comprises a key, keyboard and/or cooperating means, as claimed in any one of claims 1 to 51.

54. A computer, substantially according to any example hereinbefore described.

55. A computer, substantially according to any example hereinbefore described with reference to and illustrated in the accompanying drawings.

56. Computer output material, characterised in that it is produced by a computer as claimed in any one of claims 52 to 55.

57. Computer output signals, characterised that they are produced by a computer as claimed in any one of claims 52 to 55.

58. Computer programming means or other software applying means, characterised in that the programming or software thereof is produced by a computer as claimed in any one of claims 52 to 55.