Software keyboard system using trace of stylus on a touch screen and method for recognizing key code using the same

• US 6,292,179 B1
• Filed: 05/06/1999
• Issued: 09/18/2001
• Est. Priority Date: 05/12/1998
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Jin-chul
• Primary Examiner(s): Nguyen, Chanh
• Assistant Examiner(s): Anyaso, Uchendu O.
• Application Number:
  US09/304,268
• Time in Patent Office: 866 Days
• Field of Search: 345/173, 345/179, 345/168, 345/174-178, 400/165.1, 382/180-190
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0236 using selection techniques to select from displayed items
• CPC Class Codes: G06F 3/0482 Interaction with lists of selectable items, e.g. menus
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text
• CPC Class Codes: G06F 3/04886 by partitioning the display area of the touch-screen or the surface of the digitising tablet into independently controllable areas, e.g. virtual keyboards or menus

Abstract

A software keyboard system using the trace of a stylus and a method of recognizing key codes in accordance with the keyboard system are provided. The software keyboard system includes a screen for displaying a keyboard image or other information, a touch panel formed of a transparent material covered on the screen, for generating a coordinate value in accordance with a position pressed by a stylus, an analog-to-digital (A/D) converter for converting an analog coordinate value generated by the touch panel to a digital coordinate value, a memory for storing names of keys forming a keyboard image displayed on the screen and direction range information of a plurality of key codes assigned to each of keys, and a controller for displaying the keyboard image formed by the key names on the screen, receiving a digital value for the trace of the stylus output from the analog-to-digital (A/D) converter to retrieve a position of the stylus and a direction of the trace, reading a key code from the memory according to the stylus position and the trace direction, and outputting the key code. Thus, one key includes numerous codes, to thereby reduce the number of keys, so that the size of the keyboard is reduced without reducing the key size, to thereby facilitate use of the key.

Claims

1. A software keyboard system using a touch screen, comprising:

a screen displaying a keyboard image;

a touch panel on said screen, generating a coordinate value in accordance with a position pressed by a stylus;

a converter receiving said coordinate value and outputting a digital value;

a memory storing;

names of keys forming said keyboard image,

for each of said keys, a plurality of respective key codes, and

for each of said key codes, corresponding screen and direction range information;

a controller controlling said display of said keyboard image, receiving said digital value for a trace of said stylus, and determining the position and direction of said trace;

wherein said controller selects one of said key codes based on said position and on said direction of said trace, and

wherein said controller controls said screen to display, in said keyboard image, an image of said generated key code for a predetermined time after said controller selects said one of said key codes, and then to restore said image of said generated key code to its original state.

2. The software keyboard system of claim 1, wherein said controller controls said screen to change a character color and a background color of said image of said generated key code.

3. The software keyboard system of claim 1, wherein said controller controls said screen to enlarge only said generated key code.

4. The software keyboard system of claim 1, wherein said memory further comprises:

key code tables, each corresponding to one of said keys, storing said corresponding screen and direction range information of said plurality of respective key codes, and

a key information table storing said names of keys and address information indicating, for each of said keys, the corresponding one of said key code tables.

5. The software keyboard system of claim 1, wherein said direction range information is different for each of said plurality of respective key codes of one of said keys.

6. The software keyboard system of claim 5, wherein the direction range information of the key code includes a minimum value and a maximum value of said trace direction of said stylus.

7. A method for recognizing key codes, in a software keyboard system using a touch panel, comprising the steps of:

(a) displaying an image of a keyboard including keys with a plurality of key codes;

(b) obtaining the trace of a stylus;

(c) determining a key area in which the trace of the stylus is drawn;

(d) obtaining a direction of the trace drawn on the determined key area;

(e) searching key code information in accordance with the key area and the trace direction to generate a selected key code of the plurality of key codes of the key area; and

(f) displaying on the image of the keyboard an image of the key code generated by step (e) to be distinguished from the others of the plurality of key codes, and then restoring the image to its original state.

8. The method of claim 7, wherein the step (b) of obtaining the trace of the stylus, comprises the steps of:

(b1) obtaining a coordinate value of a start point of the trace;

(b2) obtaining a coordinate value in which the stylus contacts the touch panel, after a predetermined time; and

(b3) determining whether the point obtained in the step (b2) is an end point, thereby obtaining the end point of the trace.

9. The method of claim 7, wherein step (c) includes checking whether all coordinate values of the trace drawn by the stylus are within the range defined as a key area.

10. The method of claim 7, wherein step (c) includes checking whether a part of coordinate values of the trace drawn by the stylus is within the range defined as a key area.

11. A method for recognizing key codes, in a software keyboard system using a touch panel, comprising the steps of:

(a) displaying an image of a keyboard including keys with a plurality of key codes;

(b) obtaining the trace of a stylus;

(c) determining a key area in which the trace of the stylus is drawn;

(d) obtaining a direction of the trace drawn on the determined key area; and

(e) searching key code information in accordance with the key area and the trace direction to generate a selected key code of the plurality of key codes of the key area,

wherein said step (d) comprises the steps of;

(d1) obtaining a vector composed of coordinate values of a start point and an end point of the stylus trace;

(d2) calculating the magnitude of the obtained vector;

(d3) comparing the magnitude of the vector with the magnitude of a reference vector; and

(d4) determining a trace direction to be zero when the vector magnitude is smaller than the magnitude of the reference vector, and obtaining the trace direction by calculating an angle between the vector and a reference line when the magnitude of the vector is larger than the magnitude of the reference vector.

12. The method of claim 11, wherein step (d1) comprises compensating for the stylus sliding on the touch panel by removing an initial unstable stroke from the trace.

13. A method for recognizing key codes, in a software keyboard system using a touch panel, comprising the steps of:

(a) displaying an image of a keyboard including keys with a plurality of key codes;

(b) obtaining the trace of a stylus;

(c) determining a key area in which the trace of the stylus is drawn;

(d) obtaining a direction of the trace drawn on the determined key area; and

(e) searching key code information in accordance with the key area and the trace direction to generate a selected key code of the plurality of key codes of the key area,

wherein said step (d) comprises;

dividing the trace of the stylus into a plurality of partial traces, defining vectors, each including coordinate values of a partial trace start point and a partial trace end point, each having a respective magnitude;

weighting each of the vectors with a value proportional to said respective magnitude to provide weighted vectors, and

obtaining a trace direction of the stylus by averaging the weighted vectors.