GB2453203A

GB2453203A - Radio frequency electronic whiteboard using printed circuit board as detecting surface

Info

Publication number: GB2453203A
Application number: GB0814482A
Authority: GB
Inventors: Chun To Lau
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-09-28
Filing date: 2008-08-07
Publication date: 2009-04-01
Also published as: CN201112112Y; GB0814482D0

Abstract

An electronic whiteboard uses parallel copper traces of a printed circuit board (PCB) as the detecting surface. Each copper trace is terminated with a capacitor and resistor. The combination enables the picking up of radio frequency emitted from the transmitter pen. With the proper gain stage, the detected signal can identify the proximity of the writing pen. The fundamental or harmonic frequencies of the transmitter pen may determine the colour of the pen.

Description

Page 1

Description

Radio Frequency Electronic Whiteboard using R] as detecting surface There are several approaches to implement the design of electronic whiteboard, lnfra-RecJ detection, magnetic induction detection, video camera, etc. The basic method is to find a way to determine the X-detecting axis and the Y-detecting axis of the writing pen. The use of parallel straight metal traces on a printed circuit board to detect a radio freqeuncy emitting pen, is the most cost effective way to build eletronic whiteboards.

This invent ion relates to a method for the detection to co-ordinate a radio frequency sinewave emitting pen with the use of parallel metal traces on a printed circuit board (PCB) as the detecting surface.

The radio frequency emitting pen is shielded with only the tip of the pen exposed so as to confine the emitting area. With proper impedance at either ends of each metal trace, the detected radio signal can then be amplified and processed to give the digital equivalence for which the active detecting X-axis and Y-axis can be determined, and the proximity of the pen can be identified with the use of digital logics. The accuracy of the detection can be adjusted by changing the space between the parallel traces.

Since the detecting surface is made only of a printed circuit board, all the interfacing components can also be stuffed onto the same PCB. It dramatically *" simplifies the production of the electronic whiteboard without the intervention of human alignments, and the material cost will be reduced significantly.

:., Figure 1 shows the basic idea of the radio frequency detecting whiteboard.

* Figure 2 shows the use of termination capacitors/resistors at each end of the trace.

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The idea was filed under the same name of the inventor, Lau Chun To, in China on 25th September 2007 and the China patent no. ZL 2007 2 0172112.0 was granted on 9th July 2008.

Claims

Page 2 CLAIMS

1. A radio frequency electronic whiteboard, the writing surface being a printed circuit board with parallel metal lines.

2. A radio frequency electronic whiteboard according to claim 1, in which the fundamental or harmonic frequencies of the transmitter pen determines the color of the pen.

3. A radio frequency electronic whiteboard according to claim 1, in which at least one side of the writing surface is making up of parallel metal lines.

4. A radio frequency electronic whiteboarti according to claim 3, in which at least one side of the metal line is terminated with impedance to voltage ground.

5. A radio frequency electronic wh,teboard according to claim 1, in which the metal line forms part of the detecting circuit.

6. A radio frequency electronic whiteboard according to claim 1, in which the printed circuit board is a layer of metal on the top of a flat panel. * 10 * S * * ** * *** * S...

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