Digitizer tablet apparatus with edge area as a macro cell

• US 6,184,864 B1
• Filed: 05/07/1998
• Issued: 02/06/2001
• Est. Priority Date: 05/07/1998
• Status: Expired due to Term

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Aiptek International Incorporated (Aiptek Incorporated)
• Inventors: Chao, Ching-Chuan
• Primary Examiner(s): Shankar, Vijay
• Assistant Examiner(s): Said, Mansour M.
• Application Number:
  US09/074,505
• Time in Patent Office: 1,006 Days
• Field of Search: 345/173, 345/176, 345/179, 345/157, 345/169, 345/100, 345/126, 345/905, 178/18.01, 178/18.03, 178/18.05, 178/18.06, 178/18.07, 178/19.01, 178/19.02, 178/19.03, 178/19.04, 178/19.05, 178/20.01, 340/706, 340/707, 340/709, 340/710
• US Class Current: 345/157
• CPC Class Codes: G06F 3/046 by electromagnetic means
• 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 digitizer tablet apparatus uses edge areas on the surface of the apparatus as macro cell areas. The location of a pointing device in the apparatus is determined from a plurality of detected magnetic voltages. Threshold values are used to determine if the pointing device is in an edge area. A macro cell in an edge area may be a relative precise macro cell or a coarse macro cell. When a pointing device is in an edge area, the detected voltages may not provide enough data for determining the exact location of the pointing device. If only the exact location in X direction or Y direction can not be determined, the macro cell selected by the pointing device is a relative precise macro cell. If the exact location in both X direction and Y direction can not be determined, the macro cell is a coarse macro cell.

Claims

1. A method for identifying a macro cell selected by a pointing device in an edge area of a digitizer tablet apparatus having magnetic voltage detection loops, comprising the steps of:

a. establishing a tablet coordinate system for said digitizer tablet apparatus, said tablet coordinate system having orthogonal first and second axes;

b. detecting a first plurality of voltages from a first group of said voltage detection loops and a second plurality of voltages from a second group of said voltage detection loops;

c. checking if first and second coordinates where said pointing device is positioned in said edge area along first and second axis directions respectively can be determined from said first and second pluralities of voltages or not;

d. determining if said pointing device is located in a first axis edge area or a second axis edge area from said first and second pluralities of voltages;

e. determining a macro cell number in said second axis direction if said pointing device is determined to be in a first axis edge area and said second coordinate can not be determined, or determining a macro cell number in said first axis direction if said pointing device is determined to be in a second axis edge area and said first coordinate can not be determined; and

f. identifying said macro cell as a relative precise macro cell if only one of said first and second coordinates can not be determined;

otherwise, identifying said macro cell as a coarse macro cell.

2. The method as claimed in claim 1, wherein said step f. further includes the steps of:

g. identifying said macro cell as a relative precise macro cell if said pointing device is determined to be in a first axis area and said second coordinate can be determined, or identifying said macro cell as a coarse macro cell with a macro cell number if said pointing device is determined to be in a first axis area and said second coordinate can not be determined;

or

h. identifying said macro cell as a relative precise macro cell if said pointing device is determined to be in a second axis area and said first coordinate can be determined, or identifying said macro cell as a coarse macro cell with a macro cell number if said pointing device is determined to be in a second axis area and said first coordinate can not be determined.

3. The method as claimed in claim 1, wherein said step d. includes using threshold values for determining if said pointing device is located in a first axis edge area or a second axis edge area, said threshold values depending on environment noise, distance between the surface of said digitizer tablet apparatus to detectable location of said pointing device.

4. The method as claimed in claim 1, wherein said step d. includes using threshold values for determining if said pointing device is located in a first axis edge area, said threshold values depending on the width of said first axis edge area.

5. The method as claimed in claim 1, wherein said step d. includes using threshold values for determining if said pointing device is located in a second axis edge area, said threshold values depending on the width of said second axis edge area.