Position digitizing using an optical stylus to image a display

• US 20060250381A1
• Filed: 05/06/2005
• Published: 11/09/2006
• Est. Priority Date: 05/06/2005
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Geaghan, Bernard O.
• Granted Patent: US 7,646,377 B2
• Time in Patent Office: Days
• US Class Current: 345/179
• CPC Class Codes: G06F 3/0317 in co-operation with a patterned surface, e.g. absolute position or relative movement detection for an optical mouse or pen positioned with respect to a coded surface
• CPC Class Codes: G06F 3/0321 by optically sensing the absolute position with respect to a regularly patterned surface forming a passive digitiser, e.g. pen optically detecting position indicative tags printed on a paper sheet constructional details of pen-shaped pointing devices G06F3/03545, G06F3/03542, G06F3/037
• CPC Class Codes: G06F 3/03545 Pens or stylus

Abstract

The present invention provides systems and methods of using an stylus that houses optics and a detector capable of imaging display pixels. Stylus position is determined according to the number and direction of imaged pixels passing through the field of view of the stylus optics. Stylus orientation, including rotation and tilt, stylus height, stylus contact state, and stylus pressure may also be determined.

Claims

1. A digitizer system comprising:

a display device comprising a plurality of pixels;

an optical stylus configured to image the pixels within a field of view;

electronics in communication with the optical stylus and configured to determine the distance and direction of travel of the optical stylus based on the number and direction of pixels passing through the field of view.

2. The digitizer system of claim 1, wherein the display device is a liquid crystal display.

3. The digitizer system of claim 1, wherein the display device is an electroluminescent display.

4. The digitizer system of claim 1, wherein the display device is a cathode ray tube display.

5. The digitizer system of claim 1, wherein the field of view is a circle.

6. The digitizer system of claim 1, wherein the field of view is a ring.

7. The digitizer system of claim 1, wherein the field of view is a cross.

8. The digitizer system of claim 1, wherein the optical stylus comprises a tip switch for determining whether the stylus is in contact with a surface.

9. The digitizer system of claim 8, wherein the tip switch is further configured for determining an amount of pressure applied when the optical stylus is in contact with a surface.

10. The digitizer system of claim 1, wherein the optical stylus comprises first optics and second optics such that the field of view includes a central field of view associated with the first optics in which the pixels are individually discernable and a peripheral field of view associated with the second optics having a lower magnification for discerning displayed features larger than the pixels.

11. The digitizer system of claim 1, wherein the electronics are further configured to determine the stylus rotation orientation.

12. The digitizer system of claim 1, wherein the electronics are further configured to determine the stylus tilt angle.

13. The digitizer system of claim 1, wherein the electronics are further configured to determine the stylus height above the display surface.

14. A method of detecting stylus position relative to a pixilated display device comprising the steps of:

imaging the display pixels using optics and a detector housed by the stylus, the optics and detector providing a field of view;

obtaining stylus position relative to a reference point by determining the number and direction of pixels passing through the field of view.

15. The method of claim 14, further comprising determining the reference point.

16. The method of claim 15, wherein determining the reference point comprises using the display to display a coded pattern indicative of position that can be imaged by the stylus to determine absolute position.

17. The method of claim 14, further comprising using secondary optics housed by the stylus to image displayed features larger than the pixels.

18. The method of claim 14, further comprising determining stylus height over the display based on intensity of light reaching the detector.

19. The method of claim 14, further comprising performing a calibration step to determine characteristics of the pixels.