RF proximity sensor

• US 8,766,657 B2
• Filed: 08/19/2011
• Issued: 07/01/2014
• Est. Priority Date: 06/17/2011
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: DeJean, Gerald, Thai, Trang
• Primary Examiner(s): Nguyen, Tung X
• Assistant Examiner(s): LE, THANG XUAN
• Application Number:
  US13/214,025
• Publication Number:
  US 20120319760A1
• Time in Patent Office: 1,047 Days
• Field of Search: 32475016-75017, 324/754.28, 324/519, 324/658, 324/661, 324/662, 324/686, 324/681, 324/207.11, 345/173, 345/174, 345/176, 327/517, 702/150, 737/24
• US Class Current: 324/750.17
• CPC Class Codes: G01S 11/02 using radio waves G01S19/00 takes precedence
• CPC Class Codes: G01S 13/06 Systems determining position data of a target
• CPC Class Codes: H03K 17/955 using a capacitive detector
• CPC Class Codes: H03K 2217/960755 Constructional details of capacitive touch and proximity switches

Abstract

A sensor has a strip resonator filter that energizes an emitter patch which emits an electric field out from the strip resonator filter (away from the strip resonator filter). The capacitance of the filter, or specifically the coupling capacitance and radiation pattern of the slotted patch, is altered when an object such as a finger is near the sensor. Resulting changes in a signal outputted by the filter can be used to determine how close the object is to the sensor. The strip resonator filter may be a half wavelength strip resonator coupled filter having three separate strips. The patch may have a slot and two accompanying strips. An arrangement of multiple sensors may detect the position of an object in two or three dimensions.

Claims

1. A sensor comprising:

a first substrate layer;

a second substrate layer;

a half wavelength strip resonator between the first substrate layer and the second substrate layer; and

a conductive patch and a pair of parasitic strips, the patch and the parasitic strips separated from the half wavelength strip resonator by the second substrate layer, wherein the strips are arranged such that the patch is between the parasitic strips, wherein the conductive patch comprises a conductive island that is not conductively connected with any other conductor of the sensor.

2. A sensor according to claim 1, the conductive patch further comprising an opening within the patch.

3. A sensor according to claim 1, the patch having a rectangular shape.

4. A sensor according to claim 3, the strips comprising rectangles of conductive material.

5. A sensor according to claim 1, the half wavelength strip resonator comprising two outer strips and an inner strip, all mutually parallel in a given direction, wherein the strips are not conductively connected to each other.

6. A sensor according to claim 1, wherein the half wavelength strip resonator couples energy with the conductive patch when the sensor is powered.

7. A sensor according to claim 1, wherein the half wavelength strip resonator comprises a first terminal and a second terminal, and power is supplied to the first terminal.

10. A sensor according to claim 1, further comprising a second sensor comprised of a second half wavelength strip resonator and a second corresponding patch energized by the second half wavelength strip.

11. A sensor according to claim 10, wherein the sensor and the second sensor are members of a grid of sensors each comprising respective patches and respective halve wavelength strip filters.

17. A sensor according to claim 1, wherein each parasitic strip comprises a respective conductive island not conductively connected with any other electrical components of the sensor.

18. A sensor according to claim 1, wherein when the sensor is powered, sensing is provided by a circuit of the half wavelength resonator, the circuit not including the patch or the parasitic strips.

8. A sensor comprising:

a first substrate layer;

a second substrate layer;

a half wavelength strip resonator between the first substrate layer and the second substrate layer; and

a conductive patch and a pair of parasitic strips, the patch and the parasitic strips separated from the half wavelength strip by the second substrate layer, wherein the strips are arranged such that the patch is between the parasitic strips, wherein the half wavelength strip resonator comprises a first terminal and a second terminal, wherein power is supplied to the first terminal, and wherein the second terminal is terminated to reflect a signal back through the half wavelength strip resonator to be measured at or beyond the first terminal.

9. A sensor comprising:

a first substrate layer;

a second substrate layer;

a half wavelength strip resonator between the first substrate layer and the second substrate layer; and

a conductive patch and a pair of parasitic strips, the patch and the parasitic strips separated from the half wavelength strip by the second substrate layer, wherein the strips are arranged such that the patch is between the parasitic strips, wherein the half wavelength strip resonator comprises a first terminal and a second terminal, wherein power is supplied to the first terminal, and, wherein the second terminal is connected with circuitry that measures voltage and/or frequency of the second terminal.

12. A sensor comprising:

a half wavelength strip filter comprised of a conductive first strip, a conductive second strip, and a conductive third strip, the first strip having a first terminal connected with a power source capable of supplying power;

an emitter comprising a conductive patch and two accompanying conductive parasitic strips operatively coupled with the patch but not contacting the patch, wherein when the power source supplies power to the half wavelength strip filter, the strip filter capacitively energizes the emitter causing the emitter to emit an electric field; and

a first substrate between the half wavelength strip filter and the emitter.

13. A sensor according to claim 12, further comprising a circuit that measures proximity of an object near the sensor based on a signal at the first terminal when the power source supplies power.

14. A sensor according to claim 12, further comprising a measurement circuit, the third strip further comprising a second terminal that either terminates the third strip and reflects a signal back through half wavelength strip filter to the measurement circuit, or instead passes the signal beyond the half wavelength strip filter to the measurement circuit.

15. A sensor according to claim 12, wherein the first strip does not contact the second strip, the first strip does not contact the third strip, and the second strip does not contact the third strip.

16. A sensor according to claim 12, wherein the patch comprises a slot opening that is perpendicular to the parasitic strips, the parasitic strips each parallel to respective parallel outer edges of the conductive patch and not contacting the conductive patch.