Light sensing device for sensing ambient light intensity

• US 9,797,768 B2
• Filed: 11/26/2013
• Issued: 10/24/2017
• Est. Priority Date: 12/20/2012
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Maass, Henning, Msch, Guido Josef
• Primary Examiner(s): Luu, Thanh
• Application Number:
  US14/648,739
• Publication Number:
  US 20150300875A1
• Time in Patent Office: 1,428 Days
• Field of Search: 250214 AL
• CPC Class Codes: A61B 2560/0242 adapted to measure environmental factors, e.g. temperature, pollution
• CPC Class Codes: A61B 2560/0475 Special features of memory means, e.g. removable memory cards
• CPC Class Codes: A61B 5/165 Evaluating the state of mind, e.g. depression, anxiety
• CPC Class Codes: A61B 5/4857 Indicating the phase of biorhythm clocks or watches with indicators for biological cycles G04B19/264
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: G01J 1/0228 Control of working procedures; Failure detection; Spectral bandwidth calculation
• CPC Class Codes: G01J 1/0233 Handheld
• CPC Class Codes: G01J 1/4204 with determination of ambient light solar light G01J2001/4266
• CPC Class Codes: G01J 2001/0257 portable

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.

Claims

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.