Apparatus and method for determining an inclination of an elongate object contacting a plane surface

• US 7,110,100 B2
• Filed: 11/04/2003
• Issued: 09/19/2006
• Est. Priority Date: 11/04/2003
• Status: Active Grant

• Current Assignee: Electronic Scripting Products, Inc.
• Original Assignee: Electronic Scripting Products, Inc.
• Inventors: Buermann, Dale H., Gonzalez-Banos, Hector H., Mandella, Michael J., Carl, Stewart R.
• Primary Examiner(s): Toatley, Jr., Gregory J.
• Assistant Examiner(s): Akanbi, Isiaka O.
• Application Number:
  US10/701,817
• Publication Number:
  US 20050107979A1
• Time in Patent Office: 1,050 Days
• Field of Search: 356/138, 356/139, 356/139.1, 250/206.1, 250/206.2, 341/5, 178/18.09, 178/18.11, 382119-123
• US Class Current: 356/138
• CPC Class Codes: G06F 3/03545 Pens or stylus

Abstract

An apparatus and method for determining an inclination angle θ between an axis of an elongate object such as a cane, a pointer or a jotting implement such as a pen, pencil, stylus or the like and a normal to a plane surface at times when a tip of the elongate object is contacting that plane surface. The apparatus has an emitter mounted on the object for illuminating the plane surface with a probe radiation at an angle σ with respect to the axis of the object. The apparatus also has a detector mounted on the elongate object for detecting a radiation characteristic of a scattered portion of the probe radiation returning from the plane surface and a computing unit for deriving the inclination angle θ from the radiation characteristic. A scanning arrangement, such as a uniaxial or biaxial scanner, or a light guiding optic can be used for varying angle σ, and the probe radiation can be emitted in the form of a scan beam. Preferably, the emitter and detector of the scattered portion of the probe radiation are integrated and the scattered portion of the probe radiation whose characteristic is being measured is the back-scattered portion. The radiation characteristic detected by the detector can be the intensity, polarization, time-of-flight or any combination thereof.

Claims

1. An apparatus for determining an inclination angle θ

between an axis of an elongate object contacting a plane surface with a tip and a normal to said plane surface, said apparatus comprising;

a) an emitter on said elongate object for illuminating said plane surface with a probe radiation at an angle σ

to said axis;

b) a detector on said elongate object for detecting a radiation characteristic of a scattered portion of said probe radiation returning from said plane surface; and

c) a computing unit for deriving said inclination angle θ

from said radiation characteristic.

2. The apparatus of claim 1, further comprising a scanning arrangement for varying said angle σ

.

3. The apparatus of claim 2, wherein said scanning arrangement comprises a uniaxial scanner for varying an x-component σ

_x of said angle σ

by introducing an x-deflection γ

_x.

4. The apparatus of claim 3, wherein said uniaxial scanner further comprises a scan arm having a uniaxial scan mirror and an X-driver for controlling said x-deflection γ

_x.

5. The apparatus of claim 2, wherein said scanning arrangement comprises a biaxial scanner for varying an x-component σ

_x and a y-component σ

_y of said angle σ

by introducing an x-deflection γ

_x and a y-deflection γ

_y.

6. The apparatus of claim 5, wherein said biaxial scanner further comprises a scan arm having a biaxial scan mirror and an X-driver for controlling said x-deflection γ

_x and a Y-driver for controlling said y-deflection γ

_y.

7. The apparatus of claim 1, further comprising a light guiding optic for determining said angle σ

.

8. The apparatus of claim 1, wherein said emitter and said detector are integrated.

9. The apparatus of claim 1, wherein said emitter and said detector are offset.

10. The apparatus of claim 1, wherein said detector comprises a time-of-flight measuring unit and said radiation characteristic is a flight time.

11. The apparatus of claim 1, wherein said emitter emits said probe radiation in a polarization state and said radiation characteristic is a polarization.

12. The apparatus of claim 1, wherein said detector comprises an intensity measurement unit and said radiation characteristic is a back-scattered intensity.

13. The apparatus of claim 1, further comprising an optic for shaping said probe radiation into a scan beam.

14. The apparatus of claim 1, further comprising a scanning arrangement having a number of scan arms for shaping said probe radiation into a corresponding number of scan beams.

15. The apparatus of claim 1 wherein said elongate object is selected from the group consisting of jotting implements, pointers and canes.

16. The apparatus of claim 15, wherein said jotting implements are selected from the group consisting of pens, pencils and styluses.

17. The apparatus of claim 1, wherein said computing unit is located on said elongate object.

18. The apparatus of claim 1, wherein said emitter is a single frequency emitter.

19. A method for determining an inclination angle θ

between an axis of an elongate object contacting a plane surface with a tip and a normal to said plane surface, said method comprising;

a) illuminating said plane surface with a probe radiation from said elongate object and at an angle σ

to said axis;

b) detecting a radiation characteristic of a scattered portion of said probe radiation returning from said plane surface to said object; and

c) deriving said inclination angle θ

from said radiation characteristic.

20. The method of claim 19, further comprising shaping said probe radiation into a scan beam.

21. The method of claim 19, further comprising varying said angle σ

in a scan pattern.