Sequential stroke keyboard

• US 6,378,234 B1
• Filed: 04/09/1999
• Issued: 04/30/2002
• Est. Priority Date: 04/09/1999
• Status: Expired due to Fees

• Current Assignee: Ching-Hsing Luo
• Original Assignee: Ching-Hsing Luo
• Inventors: Luo, Ching-Hsing
• Primary Examiner(s): Horabik, Michael
• Assistant Examiner(s): WONG, ALBERT KANG
• Application Number:
  US09/288,692
• Time in Patent Office: 1,117 Days
• Field of Search: 341/20, 341/22, 341/26, 341/23, 329/68, 708/142, 708/146
• US Class Current: 341/22
• CPC Class Codes: G06F 3/0233 Character input methods
• CPC Class Codes: H01H 13/70 having a plurality of operating members associated with different sets of contacts, e.g. keyboard mounting together a plurality of independent switches H02B
• CPC Class Codes: H01H 2217/014 handicapped
• CPC Class Codes: H01H 2225/008 Two different sites for one circuit, e.g. for safety
• CPC Class Codes: H01H 2300/054 Application timeslot: duration of actuation or delay between or combination of subsequent actuations determines selected function

Abstract

A keyboard having fewer keys than the characters available utilizes linked sequences of keystrokes in generation of some characters. Other characters may be produced with one keystroke. The difference between linked keystrokes and independent keystrokes both made in sequence is determined by either the length of the interval between keystrokes or use of a delimiting key. A threshold level for the interval between keystrokes which decides whether two sequential keystrokes are linked or not may be set by the user or may be automatically determined with the use of an adaptive predictive algorithm. It is generally suggested that pairs of keys be linked, particularly adjacent pairs of keys in a fixed configuration, and that the characters generated by either a single keystroke of a given key or the characters generated by two linked keystrokes be represented upon the keyboard in a disposition which facilitates intuitive learning of the keyboard. The characters ‘A’ and ‘B’ might both be represented between the keys identified as ‘1’ and ‘2’ with the ‘A’ adjacent the ‘1’ and the ‘B’ adjacent the ‘2’ connoting that the linked keystrokes 1-2 generate the character ‘A’, the linked keystrokes 2-1 generate the character ‘B’ and independent keystrokes 1 and 2 each generate the characters ‘1’ and ‘2’ respectively. The keys may be identified and arranged in a fixed configuration in any manner desired. A hexagonal pattern with keys identified by a simplified Morse code using ·, -, ··, --, ·-, and -· is specifically suggested for use by those having a physical disability.

Claims

1. A keyboard system suited for one-handed entry of information into a digital device comprising:

a plurality of keys in a fixed configuration each labeled by a first character generated by a single keystroke of the key wherein the sequential stroking of two adjacent keys generates a second or a third character;

an encoder connected to the plurality of keys that generates a unique key code in response to stroking of each key;

a function key that outputs an enter signal when stroked or a threshold timer that outputs an enter signal when a predetermined threshold interval between keystrokes has been exceeded;

a translator that outputs a character code upon receipt of one or two key codes and an enter signal, said character code corresponding to;

a) a first character when one single key code and said enter signal are received,

b) a second character when two key codes in a sequential order and said enter signal are received,

c) a third character when two keys codes in a reverse sequential order and said enter signal are received.

2. The keyboard system of claim 1 having said sequential order determined by representation of said second character proximate the key struck first.

3. The keyboard system of claim 1 having said sequential order determined by representation of said second character proximate the key struck second.

4. The keyboard system of claim 1 having a fourth character represented proximate one key, but not between two keys, that is generated by said translator upon receipt of the key code for said one key twice and said enter signal.

5. The keyboard system of claim 1 having a full range of ten numeric characters each generated with a particular sequence of keystrokes.

6. The keyboard system of claim 1 having a plurality of punctuation symbols each generated with a particular sequence of keystrokes.

7. The keyboard system of claim 1 wherein said adjacent pair of keys are horizontally adjacent.

8. The keyboard system of claim 1 wherein said adjacent pair of keys are vertically adjacent.

9. The keyboard system of claim 1 wherein said adjacent pair of keys are diagonally adjacent.

10. The keyboard system of claim 1 further including an annunciator.

11. The keyboard system of claim 1 further including a visual display.

12. The keyboard system of claim 11 including a liquid crystal diode visual display.

13. The keyboard system of claim 1 having alphabetic characters generated with one group of keys and symbolic characters generated with another group of keys.

14. The keyboard system of claim 13 wherein the group of keys generating alphabetic characters is separated from the group of keys generating numeric characters.

15. The keyboard system of claim 1 wherein said fixed configuration of keys is comprised of a plurality of offset rows.

16. The keyboard system of claim 15 wherein said fixed configuration of keys comprises a diamond pattern.

17. The keyboard system of claim 1 possessing a plurality of centrally grouped and peripherally disposed keys.

18. The keyboard system of claim 17 possessing two platform areas each having a substantially smooth surface for resting the heel of a hand.

19. The keyboard system of claim 18 wherein the platform areas are raised with respect to the centrally grouped keys.

20. The keyboard system of claim 1 having a fill range of alphabetic characters each generated with a particular sequence of keystrokes.

21. The keyboard system of claim 20 wherein each alphabetic character is generated with a sequentially linked pair of keystrokes.

22. The keyboard system of claim 21 having upper case alphabetic second characters and lower case alphabetic third characters generated with reversed sequentially linked pairs of keystrokes.

23. The keyboard system of claim 1 wherein said fixed configuration of keys is comprised of twelve keys arranged in three columns and four rows.

24. The keyboard system of claim 23 wherein ten of said twelve keys are each labeled with one of the ten numeric characters 0-9 and two of said twelve keys are each labeled with one symbolic character.

25. The keyboard system of claim 24 wherein one of said two keys labeled with a symbolic character comprises a function key generating a signal different than said enter signal.

26. The keyboard system of claim 1 having a plurality of alphabetic characters represented which each indicate by location a sequentially linked pair of keystrokes for generation.

27. The keyboard system of claim 26 wherein a full range of twenty-six alphabetic characters are represented.

28. The keyboard system of claim 27 wherein the representation of the alphabetic characters is arranged alphabetically to facilitate intuitive learning.

29. The keyboard system of claim 1 having a plurality of keys each labeled with an alphabetic character and a numeric character each respectively generated with a single keystroke of that key in an alphabetic or a numeric character generation mode.

30. The keyboard system of claim 29 wherein alternation between alphabetic and numeric modes is effected with a particular sequence of keystrokes.

31. The keyboard system of claim 29 wherein alternation between alphabetic and numeric modes is effected with a single keystroke.

32. The keyboard system of claim 31 wherein a single keystroke of a key labeled with a symbolic character effects alternation between alphabetic and numeric modes.

33. The keyboard system of claim 1 having six of said keys arranged in a hexagon.

34. The keyboard system of claim 33 wherein alphabetic characters are represented proximate said six centrally located keys arranged in a hexagon.

35. The keyboard system of claim 34 wherein representation of said alphabetic characters indicates by location sequentially linked keystrokes generating each alphabetic character.

36. The keyboard system of claim 33 wherein each of said six centrally located keys arranged in a hexagon is labeled with a Morse code symbol.

37. The keyboard system of claim 36 wherein characters are generated with single and sequentially linked keystrokes in accordance with the Morse code.

38. The keyboard system of claim 37 wherein alphabetic and numeric characters are generated with single and sequentially linked keystrokes in accordance with the Morse code.

39. The keyboard system of claim 38 wherein all the characters of International Morse Code are generated with single and sequentially linked keystrokes in accordance with the Morse code.

40. The keyboard system of claim 33 further possessing a plurality of peripherally disposed keys.

41. The keyboard system of claim 40 wherein at least one said peripherally disposed key comprises a function key generating a signal different than said enter signal.

42. The keyboard system of claim 41 wherein a mode change function key provides alternation between two different character generation modes in which different characters are generated with the same keystroke or keystrokes.

43. The keyboard system of claim 42 wherein numeric characters and punctuation symbols are generated in a numeric character generation mode.

44. The keyboard system of claim 42 wherein alphabetic characters are generated in an alphabetic character generation mode.

45. The keyboard system of claim 44 wherein generation of alphabetic characters in lower and upper cases is determined by stroking of a shift key.

46. The keyboard system of claim 1 having an external switch for activation of every key and a visual indicator associated with each key which periodically indicates that closing of the external switch will effect stroking of that key.

47. The keyboard system of claim 46 wherein each said visual indicator is comprised of a light emitting diode.

48. The keyboard system of claim 46 having a scanning strategy utilizing a dwell upon each visual indicator which follows a circulation path among a plurality of keys.

49. The keyboard system of claim 48 having more than one circulation path.

50. The keyboard system of claim 48 having two different circulation paths.

51. The keyboard system of claim 50 having one circulation path among a group of centrally located keys and one circulation path among a group of peripherally located keys.

52. The keyboard of claim 50 wherein closing of said external switch with said dwell upon a visual indicator common to both circulation paths effects alternation between the two circulation paths.

53. The keyboard system of claim 1 wherein said predetermined threshold time period between keystrokes is fixed.

54. The keyboard system of claim 1 wherein said predetermined threshold interval between keystrokes is variable.

55. The keyboard system of claim 54 wherein variation of said predetermined threshold interval is effected with a manual setting.

56. The keyboard system of claim 54 wherein variation of said predetermined threshold interval is effected with a particular sequence of keystrokes.

57. The keyboard system of claim 54 wherein variation of said predetermined threshold interval is made with selection from a plurality of discrete threshold interval values.

58. The keyboard system of claim 54 wherein variation of said predetermined threshold interval automatically adapts to a user'"'"'s typing speed.

59. The keyboard system of claim 58 wherein automatic adaptation of the variation of said predetermined threshold interval is determined by an adaptive predictive algorithm.

60. The keyboard system of claim 59 wherein said adaptive predictive algorithm has two Least Mean Square (LMS) predictors of the interval between keystrokes determining the difference between link-space and character-space intervals.

61. The keyboard system of claim 60 wherein the following adaptive predictive algorithm is utilized:

an input signal of a unit-time-period LMS predictor is given as $\begin{array}{cc}\begin{array}{ccc}{x}_u<br><br>\left(k\right)=f_u<br><br>\left(n_S<br><br>\left(k\right)\right)& \mathrm{if}& n_S<br><br>\left(k\right)<<br><br>n_{\mathrm{Smax}}\\ =f_u<br><br>\left(n_{\mathrm{Smax}}\right)& \mathrm{if}& n_S<br><br>\left(k\right)\ge <br><br>n_{\mathrm{Smax}}\end{array}& \left(1\right)\end{array}$

where n_Smax is the upper limit of n_S(k); and

a transfer function ƒ

_u(·

) is defined by $\begin{array}{cc}\begin{array}{ccc}{f}_u<br><br>\left(n_S<br><br>\left(k\right)\right)=n_S<br><br>\left(k\right)& \mathrm{if}& S<br><br>\left(k\right)=a<br><br>\text{\hspace{1em}<br><br>}<br><br>‘<br><br>\mathrm{link}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{space}’<br><br>\\ =n_S<br><br>\left(k\right)/\mathrm{\beta <br><br>}<br><br>\left(k\right)& \mathrm{if}& S<br><br>\left(k\right)=a<br><br>\text{\hspace{1em}<br><br>}<br><br>‘<br><br>\mathrm{character}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{space}’<br><br>\end{array}& \left(2\right)\end{array}$

where S/(k) is the output of a character-space decision rule at iteration k, $\begin{array}{ccc}\mathrm{\beta <br><br>}<br><br>\left(k\right)=r<br><br>\left(k\right)& \mathrm{if}& r<br><br>\left(k\right)<<br><br>{\mathrm{\beta <br><br>}}_{\max }\\ ={\mathrm{\beta <br><br>}}_{\max }& \mathrm{if}& r<br><br>\left(k\right)\ge <br><br>{\mathrm{\beta <br><br>}}_{\max }<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{wherein}\end{array}$

r(k) defined by equation (7) below is a predicted unstable inter-keystroke space ratio;

then, a predicted unit time period u(k) at iteration k is obtained from output of the predictor