Marking device for electronic presentation board
US6424340B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 26, 2001 |
| Grant date | Jul 23, 2002 |
| Priority date | — |
| Expiry date | Jul 26, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/043
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A presentation board digitizer system for large boards preferably employs at least three spaced-apart ultrasound receivers assemblies. A current position of an ultrasound transmitter is assigned as a weighted centroid of time-of-flight position measurements based on at least two pairs of receiver assemblies. The weighting used varies as a function of the transmitter across the board. A preferred structure of an ultrasound receiver assembly for use in the system employs a pair of ultrasound receivers arranged side-by-side in a line perpendicular to the surface of the presentation board. The receives are connected so as to generate a total output signal corresponding to the instantaneous sum of the ultrasound signals received at each, such that the receiver assembly is most sensitive to ultrasound signals incident from a plane adjacent to the presentation board. Also described are a transmitter device for use with a conventional pen in which the ultrasound transmitter is a cylindrical element lying coaxial with the pen and adjacent to its tip, and a jointed eraser structure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.