Proximity sensors with optical and electrical sensing capabilities

Patent metadata

Field	Value
Publication number	US-9088282-B2
Application number	US-201313750961-A
Country	US
Kind code	B2
Filing date	Jan 25, 2013
Priority date	Jan 25, 2013
Publication date	Jul 21, 2015
Grant date	Jul 21, 2015

Abstract

An electronic device may be provided with a touch screen display that is controlled based on information from a proximity sensor. The proximity sensor may have a light source that emits infrared light and a light detector that detects reflected infrared light. When the electronic device is in the vicinity of a user's head, the proximity sensor may produce data indicative of the presence of the user's head. Variations in proximity sensor output due to user hair color and smudges on the proximity sensor can be accommodated by using an electrical sensing mechanism in addition to the light sensing mechanism. The proximity sensor may include a pair of capacitive electrodes for generating an electric field in the vicinity of the device. The presence of a user's head can sufficiently disturb the electric field so as to produce data indicative of the presence of the user's head.

First claim

What is claimed is:

1. A method of operating an electronic device having a proximity sensor that includes optical proximity sensor circuitry and electrical proximity sensor circuitry, the method comprising:
with the optical proximity sensor circuitry, gathering optical proximity sensor data by emitting light and detecting corresponding reflected light;
with the electrical proximity sensor circuitry, gathering capacitive proximity sensor data by detecting a change in capacitance;
with the proximity sensor, generating an integrated sensor output signal that includes the optical proximity sensor data and the capacitive proximity sensor data; and
with signal processing circuitry, extracting only the optical proximity sensor data from the integrated sensor output signal by demodulating the integrated sensor output signal using a first control signal.

2. The method defined in claim 1 , wherein the electronic device further includes a touch screen display and control circuitry, the method further comprising:
with the control circuitry, controlling the touch screen display based on the optical proximity sensor data and the capacitive proximity sensor data.

3. The method defined in claim 1 , wherein the optical proximity sensor circuitry includes a light emitter and a light detector, and wherein gathering the optical proximity sensor data comprises emitting infrared light with the light emitter and detecting corresponding reflected infrared light with the light detector.

4. The method defined in claim 1 , wherein the electrical proximity sensor circuitry includes capacitive electrodes, and wherein gathering the capacitive proximity sensor data comprises monitoring the capacitance with the capacitive electrodes.

5. The method defined in claim 1 ,
with the signal processing circuitry, extracting the capacitive proximity sensor data from the integrated sensor output signal by demodulating the integrated sensor output signal using a second control signal that is different than the first control signal, wherein the first and second control signals are periodic control signals.

6. The method defined in claim 5 , further comprising:
with the signal processing circuitry, comparing the optical proximity sensor data and the capacitive proximity sensor data to predetermined values to determine whether an external object is in the vicinity of the electronic device.

7. The method defined in claim 5 , further comprising:
with the signal processing circuitry, computing a proximity sensor score by weighting the optical proximity sensor data and the capacitive proximity sensor data with different respective weighting factors; and
comparing the computed proximity sensor score to a predetermined threshold score to determine whether an external object is in the vicinity of the electronic device.

8. A method of operating an electronic device having a proximity sensor and associated signal processing circuitry, comprising:
generating a sensor output signal with the proximity sensor, wherein the sensor output signal comprises a first signal component corresponding to a first component in the proximity sensor that is integrated with a second signal component corresponding to a second component in the proximity sensor;
with the signal processing circuitry, analyzing the sensor output signal to extract the first signal component from the sensor output signal during a first detection mode;
with the signal processing circuitry, analyzing the sensor output signal to extract the second signal component from the sensor output signal during a second detection mode that is different than the first detection mode; and
after analyzing the sensor output signal to extract the first signal component from the sensor output signal during the first detection mode and before analyzing the sensor output signal to extract the second signal component from the sensor output signal during the second detection mode, switching from the first detection mode to the second detection mode using switching circuitry.

9. The method defined in claim 8 , wherein the electronic device further includes a touch screen display, the method further comprising:
controlling the touch screen display based on the first and second extracted signal components.

10. The method defined in claim 8 , wherein the signal processing circuitry further comprises an amplifying circuit, a data converting circuit, and a filter circuit, and wherein analyzing the sensor output signal further comprises:
amplifying the sensor output signal with the amplifying circuit;
performing data conversion operations on the amplified sensor output signals with the data converting circuit; and
performing filtering operations on the converted sensor output signals with the filter circuit.

11. The method defined in claim 8 , wherein analyzing the sensor output signal to extract the first signal component from the sensor output signal during the first detection mode comprises analyzing the sensor output signal to extract only the first signal component from the sensor output signal during the first detection mode, and wherein analyzing the sensor output signal to extract the second signal component from the sensor output signal during the second detection mode comprises analyzing the sensor output signal to extract only the second signal component from the sensor output signal during the second detection mode.

12. A method of operating an electronic device having a proximity sensor and associated signal processing circuitry, comprising:
generating a sensor output signal with the proximity sensor, wherein the sensor output signal comprises a first signal component corresponding to a first component in the proximity sensor that is integrated with a second signal component corresponding to a second component in the proximity sensor;
with the signal processing circuitry, analyzing the sensor output signal to extract the first signal component from the sensor output signal during a first detection mode; and
with the signal processing circuitry, analyzing the sensor output signal to extract the second signal component from the sensor output signal during a second detection mode that is different than the first detection mode, wherein the first component comprises optical proximity sensor structures, wherein the second component comprises capacitive proximity sensor structures, wherein the first signal component comprises optical proximity sensor data gathered using the optical proximity sensor structures, wherein the second signal component comprises capacitive proximity sensor data gathered using the capacitive proximity sensor structures, wherein extracting the first signal component comprises extracting the optical proximity sensor data from the sensor output signal, and wherein extracting the second signal component comprises extracting the capacitive proximity sensor data from the sensor output signal.

13. The method defined in claim 12 , further comprising:
comparing the extracted optical proximity sensor data to a predetermined light threshold; and
comparing the extracted capacitive proximity sensor data to a predetermined baseline capacitance.

14. The method defined in claim 12 , further comprising:
computing a proximity sensor score by weighting the optical proximity sensor data and the capacitive proximity sensor data with different respective weighting factors; and
comparing the computed proximity sensor score to a predetermined threshold score to determine whether an external object is in the vicinity of the electronic device.

15. A method of operating an electronic device having a proximity sen

Assignees

• Apple Inc

Inventors

• Holenarsipur Prashanth S S
• Rai Anant
• Lukofsky David

Classifications

• G06F3/0416

  Control or interface arrangements specially adapted for digitisers · CPC title

• H03K2017/9602

  characterised by the type or shape of the sensing electrodes · CPC title

• H03K2217/94108

  making use of reflection · CPC title

• H03K17/955 Primary

  using a capacitive detector · CPC title

• G06F2203/04106

  Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection · CPC title