Sensor apparatus and method for generating signals indicative of the position or change in position of limbs

• US 8,345,015 B2
• Filed: 04/28/2008
• Issued: 01/01/2013
• Est. Priority Date: 04/26/2007
• Status: Active Grant

• Current Assignee: Neodrón Limited (Atlantic IP Services Limited)
• Original Assignee: IDENT Technology AG (Microchip Technology Incorporated)
• Inventors: Ivanov, Artem
• Primary Examiner(s): Mengistu, Amare
• Assistant Examiner(s): PATEL, PREMAL R
• Application Number:
  US12/597,619
• Publication Number:
  US 20100063421A1
• Time in Patent Office: 1,709 Days
• Field of Search: 345/173, 345/174, 178 1801- 1809
• US Class Current: 345/173
• CPC Class Codes: G06F 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry
• CPC Class Codes: G06F 3/0383 Signal control means within the pointing device

Abstract

A sensor apparatus for generating electrical signals which indicate the position or movement of limbs relative to a reference area has a transmitter electrode apparatus, a voltage generator for applying an alternating voltage to the transmitter electrode, a first receiver electrode apparatus, a second receiver electrode apparatus, and a third receiver electrode apparatus, wherein the first, second, and third receiver electrode apparatuses are each connected to high-impedance tapping systems. The first, second, and third receiver electrode apparatuses are preferably each connected to high-impedance inputs of an impedance transformer system, wherein information indicative of a location or movement is obtained on the basis of differences between the electrical events present at the outputs of the respective impedance transformer.

Claims

1. A sensor apparatus for determining a spatial position or movement of limbs, the apparatus comprising:

a transmitter electrode,

a voltage generator for applying an alternating voltage to the transmitter electrode,

a first receiver electrode,

a second receiver electrode, and

a third receiver electrode, and

first, second, and third impedance transformers each having a high impedance input each receiving a voltage from the first, second, and third receiver electrode, respectively,

a mean value circuit coupled with the outputs of the first, second, and third impedance transformers;

a first differential amplifiers for generating a differential value between the output of the first impedance transformer and the output of the mean value circuit;

a second differential amplifiers for generating a differential value between the output of the second impedance transformer and the output of the mean value circuit;

a third differential amplifiers for generating a differential value between the output of the third impedance transformer and the output of the mean value circuit.

2. The sensor apparatus according to claim 1 wherein information indicative of a location or movement is obtained on the basis of differences between electrical signals present at the outputs of the respective impedance transformer.

3. The sensor apparatus according to claim 2 wherein a divider divides the composite signal to generate the mean value.

4. The sensor apparatus according to claim 2 comprising synchronous detectors, which generate signals indicative of the synchronicity of the output signal at the respective impedance transformers with the alternating voltage.

5. The sensor apparatus according to claim 4 wherein the information indicative of a location or movement is obtained on the basis of differences between the electrical signals present at the outputs of the respective synchronous detector.

6. The sensor apparatus according to claim 4 wherein each synchronous detector provides signals indicative of the synchronicity of a voltage level compared to the alternating voltage.

7. The sensor apparatus according to claim 4 wherein the synchronous detector provides signals indicative of the synchronicity of a phase compared to the alternating voltage.

8. The sensor apparatus according to claim 4 further comprising an ADC receiving output signals of the synchronous detector, wherein the ADC is coupled a microcontroller unit for evaluation.

9. The sensor apparatus according to claim 1 further comprising an amplifier for amplifying the output of the mean value circuit.

10. The sensor apparatus according to claim 1 wherein the receiver electrodes are disposed symmetrically around the transmitter electrode.

11. The sensor apparatus according to claim 1 wherein the transmitter electrode is supplied by a generator with an alternating current and produces a surrounding electrical field.

12. The sensor apparatus according to claim 1 wherein the receiver electrodes are disposed symmetrically around the transmitter electrode.

13. The sensor apparatus according to claim 1 wherein the voltages present at the receiver electrodes contains information about the distribution of the field of the transmitter electrode.

14. The sensor apparatus according to claim 1 wherein the voltages present at the receiver electrodes are present at the receiver electrodes of channels 1, 2, and 3.

15. The sensor apparatus according to claim 1 wherein each differential amplifier is coupled with a diode rectifier.

16. The sensor apparatus according to claim 1 wherein each differential amplifier is coupled with a peak detector.

17. The sensor apparatus according to claim 1 further comprising an ADC directly coupled with the outputs of the first, second, third differential amplifier.

18. A method for generating electrical signals that indicate the position or movement of limbs, the method comprising the steps of

applying an alternating electrical field to a transmitter electrode, and receiving voltages by at least three receiver electrodes disposed in the vicinity of the transmitter electrode,

feeding the received voltages to high impedance inputs of impedance transformers;

forming a mean value of output signals from the impedance transformers;

forming first, second and third differential signals between the mean value and the output values of the respective impedance transformers.

19. The method according to claim 18, further comprising amplifying the mean value.

20. The method according to claim 19, further comprising feeding the amplified mean value to an ADC.

21. The method according to claim 19, further comprising feeding the differential signals and the amplified mean value to an ADC and determining the position or a movement of a limb from said differential signals and said amplified mean value.

22. The method according to claim 18, further comprising determining synchronicity of the differential signals with the alternating electrical field.

23. The method according to claim 22, further comprising feeding the synchronous detection signals to an ADC.

24. The method according to claim 18, further comprising feeding the differential signals to an ADC.