WO2005045657A1 - Alphanumeric keyboard particularly for handheld computers and the like - Google Patents

Abstract

An alphanumeric keyboard particularly for handheld computers and the like, comprising thirteen triple-function keys (11), which close on a printed circuit (18), a first switch (14) so as to generate a first signal, a second switch (15) so as to generate a second signal, or both of the first and second switches (14, 15) within a predefined time interval. The first and second signals enter a processor, which converts each one of the first and second signals: - into a first character, if the first signal precedes a second signal by a time that is not shorter than the predefined interval, - into a second character, if the second signal precedes a first signal by a time that is not shorter than the predefined interval, - into a third character, if the time delay between the first and second signals is shorter than the predefined time interval.

Description

ALPHANUMERIC KEYBOARD PARTICULARLY FOR HANDHELD COMPUTERS AND THE LIKE Technical Field The present invention relates to an alphanumeric keyboard particularly for handheld computers and the like. Background Art Currently known alphanumeric keyboards for handheld computers, calculators, cellular telephones and the like are very compact and have a very small number of keys, some of which are therefore of the multifunction type. In these keyboards, in order to enter an alphanumeric text it is necessary to switch the keyboard from a first alphabetic mode to a second numeric and operator-entry mode, depending on whether one has to type letters, digits or other symbols. For this switching, there is generally a dedicated key, which a user must press every time he changes from entering digits, operators or punctuation marks, to entering letters, and vice versa. As an alternative, as occurs in most cellular telephones, each key handles up to four symbols, generally three letters and one digit. A key of this type must be pressed several times consecutively, within a short time interval, depending on the output that one wishes to obtain among the inputs offered by the key. The presence of the switching key and the need for a user to switch each time the function of the keyboard from alphabetic use to numeric and operator-entry use, as well as the need to press the same key several times in rapid sequence, considerably slow the entry of data by the user into the processor of the computer to which the keyboard is connected. In general, this slowing can only delay the activity of the user and of the personnel that depends on such activity. Disclosure of the Invention The aim of the present invention is to provide an alphanumeric key that allows to type alphabetic and numeric symbols without having to switch the keyboard from an alphabetic mode to a numeric mode and with a single actuation of the chosen key. Within this aim, an object of the present invention is to provide an alphanumeric keyboard that is particularly compact and has a limited number of multifunction keys. Another object of the present invention is to provide an alphanumeric keyboard that is compact and can be adapted easily to handheld computers, calculators and the like of a known type. Another object of the present invention is to provide an alphanumeric keyboard that can be operated conveniently by a user who lacks particular prior experience. Another object of the present invention is to provide an alphanumeric keyboard that can be manufactured cheaply with known systems and technologies. This aim and these and other objects that will become better apparent hereinafter are achieved by an alphanumeric keyboard particularly for handheld computers and the like, characterized in that it comprises at least twelve triple-function keys provided, in a lower region, with a first conducting element and a second conducting element, said first and second conducting elements forming respectively a first switch and a second switch for a first pair and a second pair of contacts of a printed circuit from which they protrude, each one of said multifunction keys being suitable to close selectively said first switch so as to generate a first signal, said second switch so as to generate a second signal, or both of said first and second switches within a predefined time interval, each one of said first and second signals entering a processor that is suitable to convert each one of said first and second signals: — into a first character, if said first signal precedes a said second signal by a time that is not shorter than said predefined interval, - into a second character, if said second signal precedes a said first signal by a time that is not shorter than said predefined interval, — into a third character, if the time delay between said first and second signals is shorter than said predefined time interval. Brief description of the Drawings Further characteristics and advantages of the invention will become better apparent from the following detailed description of a preferred but not exclusive embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein: Figure 1 is a front view of an alphanumeric keyboard according to the invention; Figure 2 is a sectional view of a triple-function key of the alphanumeric keyboard according to the invention, in a first configuration thereof; Figure 3 is a sectional view of a triple-function key of the alphanumeric keyboard according to the invention, in a second configuration thereof; Figure 4 is a sectional view of a triple-function key of the alphanumeric keyboard according to the invention, in a third configuration thereof; Figure 5 is a sectional view of a triple-function key of the alphanumeric keyboard according to the invention, in a fourth configuration thereof; Figure 6 is a block diagram of the alphanumeric keyboard according to the invention; Figure 7 is a schematic view of the operation of a key of the alphanumeric keyboard according to the invention. Ways of carrying out the Invention With reference to the figures, an alphanumeric keyboard particularly for handheld computers and the like according to the invention is generally designated by the reference numeral 10. The keyboard 10 comprises thirteen triple-function keys 11, which are provided in a lower region with a first conducting element 12 and with a second conducting element 13. The first and second conducting elements 12 and 13 form respectively a first switch 14 and a second switch 15 for a first pair of contacts 16 and a second pair of contacts 17 of a printed circuit 18, from which they protrude. Each one of the triple-function keys 11 closes selectively the first switch 14, so as to generate a first signal 40, the second switch 15, so as to generate a second signal 41, or both of the first and second switches 14 and 15 within a predefined time interval 42. The first and second signals 40 and 41 are input, by means of the printed circuit 18, to a processor 20 of a per se known type, which is suitable to convert each one of the signals 40 and 41:

- into a first character 70, if the first signal 40 precedes a second signal 41 by a time 44a that is not shorter than the predefined time interval 42,

- into a second character 71, if the second signal 41 precedes a first signal 40 by a time 44b that is not shorter than the predefined time interval 42,

- into a third character 72, if the time 43 between the first signal 40 and the second signal 41 is shorter than the predefined time interval 42. These three options are described schematically in Figure 7, while the first and second signals 40 and 41 are shown equally schematically in Figure 6. Figures 6 and 7 illustrate the operation of a single triple-function key 11, but it is understood that the example applies to all of the triple-function keys 11. The thirteen triple-function keys 11 therefore emit a total of thirteen different first signals 40 and thirteen different second signals 41. The thirteen first signals 40 and the thirteen second signals 41 generate, by means of the processor 20, thirteen first characters 70, thirteen second characters 71, and thirteen third characters 72. The time interval 42 within which a signal 40 or 41 must follow the other signal in order to make the processor return a third character 72 is substantially seventy-five milliseconds. The time interval 42 can be programmed by an operator in an interval between thirty and one hundred milliseconds, so that it is possible to choose between a high-responsiveness performance of the keyboard 10 and the precision of the keyboard 10 in detecting the closure of the two switches 14 and 15. In the embodiment of a keyboard 10 according to the invention described herein, the thirteen first characters 70 and the thirteen second characters 71 each activate uniquely one letter 51 of the English alphabet. Ten of the thirteen third characters 72 each activate uniquely a numeric symbol from 0 to 9, designated by the reference numeral 52 in Figure 1. The remaining three of the third characters 72 each activate an operator symbol 53. One of said remaining three of said third characters activates the "at" symbol, which is designated by the reference numeral 54 in Figure 1. Each triple-function key 11 protrudes from a corresponding opening

25 of a protective surface panel 26 and is suspended over the first and second pairs 16 and 17 of contacts through a corresponding opening 27 by means of an elastically deformable ring 28. The ring 28 is connected to an intermediate layer 29 for resting on the underlying printed circuit 18. Advantageously, the triple-function keys 11, the ring 28 and the intermediate layer 29 form a single body. Such single body is obtained, in this embodiment, by molding silicone rubber. The operation of the keyboard 10 is as follows. By pressing a triple-function key 11 on its sides, 1 la for the right side or l ib for the left side, as shown in Figures 5 and 3 respectively, one obtains respectively the second signals 41 and the first signals 40, generating a second character 71 and a first character 70. By pressing the triple-function key 11 at its center l ie, both pairs of contacts 16 and 17, and therefore the two switches 14 and 15, are closed substantially simultaneously, generating third characters 72. In Figure 7, the signals 40 and 41 are shown as steps. During the activation of a generic first character 70, the second signal 41, if any, is temporally separated from the first signal 40 by a time 44a that is longer than the preset time interval 42. Likewise, in the activation of a generic second character 71, the first signal 40, if any, is temporally separated from the second signal 41 by a time 44b that is longer than the preset time interval 42. In the activation of a generic third character 72, the second signal 41 follows the first signal 40 with a time interval 43 that is shorter than the time interval 42. Conveniently, and to the full benefit of the user of the keyboard 10, acoustic warning means 50 are functionally connected to the processor 20 and are suitable to emit a first acoustic signal in relation to each one of the first and second characters 70 and 71 or a different second acoustic signal in relation to each one of the third characters 72. The acoustic warning means 50 are constituted by a buzzer 51. The presence of the buzzer 51, which emits a different acoustic signal depending on whether a letter or a digit or another symbol is typed, allows the user to better perceive whether he has pressed correctly the chosen triple-function key 11. The keyboard 10 further comprises visual warning means 60 for making a distinction, on the display, between the first characters 70 and the second characters 71 and the third characters 72. The visual warning means 60 are constituted by a variation of the appearance of the cursor of the display, depending on whether one is in the presence of a first character 70 or of a second character 71 or of a third character 72. The variation of the appearance of the cursor can relate, individually or in combination, to the characteristics of shape, color, luminous intensity and flashing rate of the cursor. The visual warning means 60 further reinforce in the user the perception of having pressed correctly the chosen triple-function key 11. The acoustic warning means 50 and the visual warning means 60 allow the user to have a more evident immediate confirmation that he has pressed the generic key 11 in the chosen manner. With these means, any typing error is immediately detectable and correctable. In practice it has been found that the invention thus described solves the problems noted in known types of alphanumeric keyboard particularly for handheld computers and the like. In particular, the present invention provides an alphanumeric keyboard that allows to type alphabetic and numeric symbols without having to switch the keyboard from an alphabetic mode to a numeric mode and without having to press a same key repeatedly. Moreover, the present invention provides an alphanumeric keyboard that is particularly compact and has a limited number of multifunction keys. Moreover, the present invention provides a compact alphanumeric keyboard that can be installed easily in handheld computers, calculators and the like of a known type. Further, the present invention provides an alphanumeric keyboard that can be handled comfortably by a user who lacks particular prior experience. Moreover, the present invention provides an alphanumeric keyboard that can be produced at low cost with known systems and technologies. The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements. In practice, the materials employed, so long as they are compatible with the specific use, as well as the dimensions, may be any according to requirements and to the state of the art. The disclosures in Italian Utility Model Application No. PD2003U000101 from which this application claims priority are incorporated herein by reference.

Claims

CLAIMS 1. An alphanumeric keyboard particularly for handheld computers and the like, characterized in that it comprises at least twelve triple-function keys (11) provided, in a lower region, with a first conducting element (12) and a second conducting element (13), said first and second conducting elements (12, 13) forming respectively a first switch (14) and a second switch (15) for a first pair (16) and a second pair (17) of contacts of a printed circuit (18) from which they protrude, each one of said multifunction keys (11) being suitable to close selectively said first switch (14) so as to generate a first signal (40), said second switch (15) so as to generate a second signal (41), or both of said first and second switches (14, 15) within a predefined time interval (42), each one of said first and second signals (40, 41) entering a processor (20) that is suitable to convert each one of said first and second signals (40, 41): - into a first character (70), if said first signal (40) precedes a said second signal (41) by a time that is not shorter than said predefined interval (42),

- into a second character (71), if said second signal (41) precedes a said first signal (40) by a time that is not shorter than said predefined interval (42),

- into a third character (72), if the time delay (43) between said first and second signals (40, 41) is shorter than said predefined time interval (42).

2. The alphanumeric keyboard according to claim 1, characterized in that said first character (70), said second character (71) and said third character (72) each represent an alphanumeric symbol (50).

3. The alphanumeric keyboard according to one or more of the preceding claims, characterized in that it has thirteen keys (11), said thirteen first characters (70) and said thirteen second characters (71) each representing uniquely a letter (51) of the English alphabet.

4. The alphanumeric keyboard according to one or more of the preceding claims, characterized in that ten of said thirteen third characters (72) each represent uniquely a numeric symbol (52) from 0 to 9 and the remaining three of said third characters (72) each activate an operator symbol (53).

5. The alphanumeric keyboard according to one or more of the preceding claims, characterized in that one of said remaining three of said third characters (72) represents the "at" symbol (54).

6. The keyboard according to one or more of the preceding claims, characterized in that said predefined time interval (42) is not shorter than thirty milliseconds and not longer than one hundred milliseconds.

7. The keyboard according to one or more of the preceding claims, characterized in that said time interval (42) is seventy-five milliseconds.

8. The alphanumeric keyboard according to one or more of the preceding claims, characterized in that each key (11), which protrudes from a corresponding opening (25) of a protective surface panel (26), is suspended over said first and second pairs of contacts (16, 17) through a corresponding opening (27) by way of an elastically deformable ring (28), which is connected to an intermediate layer (29) for resting on the underlying printed circuit (18).

9. The alphanumeric keyboard according to claim 8, characterized in that said keys (11), said ring (28) and said intermediate layer (29) form a single body.

10. The alphanumeric keyboard according to claim 9, characterized in that said keys (11), said ring (28) and said intermediate layer (29), which form a single body, are obtained by molding silicone rubber.

11. The alphanumeric keyboard according to one or more of the preceding claims, characterized in that it comprises acoustic warning means (50), which are functionally connected to said processor (20) and are suitable to emit a first acoustic signal in relation to each one of said first or second characters (70, 71), or a second acoustic signal in relation to each one of said third characters (72).

12. The alphanumeric keyboard according to one or more of the preceding claims, characterized in that it comprises visual warning means (60) for providing a distinction, on the display, between said first or second characters (70, 71) and said third characters (72).

13. The alphanumeric keyboard according to claim 11, characterized in that said acoustic warning means (50) are constituted by a buzzer (51).