Module for proximity and gesture sensing

Patent metadata

Field	Value
Publication number	US-9417734-B2
Application number	US-201313942859-A
Country	US
Kind code	B2
Filing date	Jul 16, 2013
Priority date	Jul 24, 2012
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

A module operates in a proximity detection mode and a gesture detection mode. The module includes an illumination source, radiation sensors and a controller. When in proximity detection mode, the illumination source emits radiation, the radiation sensors measure the radiation level, and the controller adjusts the measured radiation level to substantially cancel the contribution attributable to ambient radiation to determine the presence of a proximate object by. When in the gesture recognition mode, the level of radiation incident on the sensors is individually sampled, and the controller determines object movement by comparing the changes in the measured radiation levels over a plurality of the samples. Ambient radiation contribution is not removed from the sampled radiation levels during the gesture recognition mode.

First claim

What is claimed is:

1. A proximity and gesture detection module, comprising:
an illumination source;
a plurality of radiation sensors; and
a controller;
said module being operable in a proximity detection mode and a gesture detection mode;
wherein, when said module is in said proximity detection mode:
said illumination source is operable to emit radiation,
said module is operable to measure the level of radiation incident on one or more of said radiation sensors, said level of radiation being attributable to ambient radiation and, when there is an object present in the field of view of said one or more of said radiation sensors, radiation from said illumination source which has been reflected by said object towards said one or more of said radiation sensors; and
said controller is operable to determine the presence of an object in the proximity of the module by adjusting said measured radiation level to substantially cancel the contribution attributable to the ambient radiation, and comparing said adjusted radiation level to a proximity threshold; and

wherein, when said module is in said gesture recognition mode:
said module is operable to repeatedly sample the level of radiation incident on each of a plurality of said sensors, individually;
said controller is operable to determine the movement of an object in the field of view of said sensors by comparing the changes in the measured radiation levels over a plurality of said samples; and
wherein any ambient radiation contribution is not removed from the sampled radiation levels during said gesture recognition mode.

2. The module as claimed in claim 1 operable, in said gesture recognition mode, to detect a gesture made by an object without making contact to a surface or other object.

3. The module as claimed in claim 1 wherein, in said proximity detection mode, the illumination source is operable to emit pulsed radiation; and the one or more radiation sensors are operable to detect the level of radiation incident thereon both when the illumination source is on and when the illumination source is off and wherein the module further comprises modulation means operable to use the measured radiation level when the illumination source is on and the measured radiation level when the illumination source is off to cancel the contribution of the measured radiation level attributable to the ambient radiation; and wherein said modulation means is operable not to be used in said gesture recognition mode.

4. The module as claimed in claim 1 , comprising an ambient radiation sensor operable to determine ambient radiation level.

5. The module as claimed in claim 4 operable in said gesture recognition mode, to: determine said ambient radiation level, compare said ambient radiation level to an ambient threshold, and activate said illumination source if said ambient radiation level is below said ambient threshold.

6. The module as claimed in claim 1 wherein, when in said gesture recognition mode, each of said plurality of sensors is operable to integrate the incident radiation thereon during an integration time.

7. The module as claimed in claim 6 wherein the controller is operable to repeat said the integration of the incident radiation with an increased integration time if it determined that the sampled radiation levels of all the sensors are all below a first integration threshold and/or wherein the controller is operable to repeat the integration of the incident radiation with a reduced integration time if it determined that the sampled radiation levels of at least one of the sensors is above a second integration threshold.

8. The module as claimed in claim 1 wherein, when in said gesture recognition mode, said controller is operable to obtain a two dimensional image from the sampled radiation level for each sample, and to determine the motion of the object in two-dimensions from changes in this image between samples.

9. The module as claimed in claim 1 operable, in said proximity detection mode, such that the outputs of said plurality of radiation sensors, or a subset thereof, are combined into a single output.

10. The module as claimed in claim 9 wherein each sensor comprises at least one switching device for selectively connecting each of said outputs to a common node.

11. The module as claimed in claim 10 wherein said at least one switching device forms a first output which is combined with outputs of other sensors to form said single output, and each sensor further comprises a second output for individual sampling of the sensor outputs in said gesture recognition mode.

12. The module as claimed in claim 9 comprising a dedicated amplifier for reading out said combined outputs at said common node.

13. The module as claimed in claim 12 wherein said dedicated amplifier is a trans-impedance amplifier.

14. The module as claimed in claim 12 wherein said dedicated amplifier is a charge integrator.

15. The module as claimed in claim 1 wherein said sensors are arranged in a two dimensional array.

16. The module as claimed in claim 15 wherein, in said gesture sensing mode, said module is operable such that every sensor is exposed simultaneously during each of said samples.

17. The module as claimed in claim 16 wherein each sensor comprises a charge integrator for obtaining an output voltage for the sensor.

18. The module as claimed in claim 17 wherein each of said sensors comprise a comparator operable to compare said output voltage to a time varying reference signal inside of the sensor.

19. The module as claimed in claim 16 wherein the module is operable to use the capacitance of said sensor's photodiode to obtaining an output voltage for the sensor.

20. The module as claimed in claim 15 wherein, in said gesture sensing mode, said controller is module is operable such that said sensors are exposed a row at a time during each of said samples.

21. The module as claimed in claim 15 wherein said module comprises a plurality of readout amplifiers, the width of said readout amplifiers being such that amplifiers for each column of the array fit entirely inside their respective column.

22. The module as claimed in claim 21 wherein, along one or more sides of the array, readout amplifiers are arranged side-by-side at the periphery of the array and,
wherein the combined width of readout amplifiers on each side of the array does not exceed the length of the adjacent side of the array.

23. The module as claimed in claim 15 wherein said array of sensors comprises a pixel array.

24. The module as claimed in claim 1 operable in said proximity detection mode when no object is being detected, and to enter said gesture recognition mode following detection of an object.

25. The module of claim 1 as incorporated within one of a mobile computing device, a mobile telephony device or an electronic reader device.

26. A method of proximity detection and gesture recognition, said method comprising:
determining whether there is an object in the proximity of a sensor in a proximity detection mode, and
following detection of an object, entering a gesture recognition mode;
wherein said proximity detection mode comprises:
emitting radiation from an illumination source,
measuring the level of radiation incident on a plurality of sensors, said level of radiation being attributable to ambient radiation and, when there is an object present in the field of said one

Assignees

• Stmicroelectronics (Research & Development) Ltd

Inventors

• Raynor Jeffrey M
• Scott Andrew

Classifications

• G06F2203/04108

  Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction · CPC title

• G06F3/017

  Gesture based interaction, e.g. based on a set of recognized hand gestures (interaction based on gestures traced on a digitiser G06F3/04883) · CPC title

• G08B13/19608

  Tracking movement of a target, e.g. by detecting an object predefined as a target, using target direction and or velocity to predict its new position · CPC title

• G01S17/10

  using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) · CPC title

• G06F3/0421 Primary

  by interrupting or reflecting a light beam, e.g. optical touch-screen · CPC title