Light sensing device for sensing ambient light intensity

Patent metadata

Field	Value
Publication number	US-9797768-B2
Application number	US-201314648739-A
Country	US
Kind code	B2
Filing date	Nov 26, 2013
Priority date	Dec 20, 2012
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

The invention relates to a light sensing device for sensing ambient light intensity, comprising at least one ambient light sensor and an occlusion detector for detecting an object occluding the ambient light sensor. The invention is further related to a corresponding method for sensing ambient light intensity.

First claim

The invention claimed is:

1. A light sensing device for sensing ambient light intensity, the light sensing device comprising:
at least one ambient light sensor configured to measure ambient light intensity;
an occlusion detector configured to detect an object occluding the ambient light sensor;
a recording device configured to store ambient light intensity values measured by the ambient light sensor and corresponding occlusion status of the ambient light sensor as a function of time; and
a processor configured to:
determine an ambient light intensity threshold based on one or more parameters, the one or more parameters comprising date and/or time of day;
activate the occlusion detector to measure a first occlusion measurement based on the determined ambient light intensity threshold; and
determine timing for subsequent activations of the occlusion detector based on the first occlusion measurement and based on the one or more parameters.

2. The light sensing device of claim 1 , wherein the occlusion detector comprises an infrared sensor and an infrared light source.

3. The light sensing device of claim 2 , comprising a casing on which the infrared sensor, the infrared light source and the ambient light sensor are positioned on the same side.

4. The light sensing device of claim 1 , wherein the light sensing device is a wrist-wearable device comprising a wristband.

5. The light sensing device of claim 1 , further comprising an indicator device for generating an audible, visual and/or haptically perceivable notification signal in case of the detection of an object by the occlusion detector.

6. The light sensing device according to claim 1 , wherein the processor is configured to activate the occlusion detector responsive to the ambient light intensity being below a predetermined threshold.

7. A method for sensing ambient light intensity by means of a light sensing device comprising at least one ambient light sensor an occlusion detector for detecting an object occluding the ambient light sensor a recording device and a processor, comprising the following steps:
performing an ambient light intensity measurement with the ambient light sensor;
determining, with the processor, an ambient light intensity threshold based on one or more parameters, the one or more parameters comprising date and/or time of day;
activating, with the processor, the occlusion detector based on the determined ambient light intensity threshold;
performing an occlusion measurement with the occlusion detector to determine if the ambient light sensor is occluded by the object;
recording, with the recording device, ambient light intensity values measured by the ambient light sensor and corresponding occlusion status of the ambient light sensor; and
determining, with the processor, timing for subsequent activations of the occlusion detector based on the first occlusion measurement and based on the one or more parameters.

8. The method of claim 7 , wherein the ambient light measurement is performed within temporally limited subsequent epochs.

9. The method of claim 8 , wherein the occlusion measurement is performed for each epoch.

10. The method according to claim 8 , wherein the occlusion measurement is performed only for epochs in which the ambient light intensity is below a predetermined threshold.

11. Method according to claim 8 , wherein the occlusion measurement is performed only for the first epoch in which the ambient light intensity is below a predetermined threshold.

12. Method according to claim 8 , wherein the occlusion measurement is performed for the first epoch in which the ambient light intensity is below a predetermined threshold and repeated periodically as long as the ambient light intensity stays below this threshold.

13. Method according to claim 8 , wherein the occlusion measurement is performed once or periodically repeated after the ambient light intensity has stayed below a predetermined threshold for a predetermined number of epochs.

14. Method according to claim 8 , wherein the predetermined threshold of ambient light intensity and/or a repetition period of occlusion measurements are adjustable by a user.

Assignees

• Koninklijke Philips Nv

Inventors

• Maass Henning
• Müsch Guido Josef

Classifications

• A61B2560/0242

  adapted to measure environmental factors, e.g. temperature, pollution · CPC title

• G01J1/4204

  with determination of ambient light (solar light G01J2001/4266) · CPC title

• G01J2001/0257

  portable · CPC title

• A61B5/4857

  Indicating the phase of biorhythm · CPC title

• A61B5/681 Primary

  Wristwatch-type devices · CPC title