System for sensing light exposure of a user

Patent metadata

Field	Value
Publication number	US-2016199000-A1
Application number	US-201414914895-A
Country	US
Kind code	A1
Filing date	Aug 26, 2014
Priority date	Aug 28, 2013
Publication date	Jul 14, 2016
Grant date	—

Abstract

The invention relates to a system ( 100 ) for sensing ambient light intensity, comprising a wearable device ( 10 ) with at least one pair of light receivers ( 20, 22, 23, 24, 25 ) arranged in two different positions for receiving light from the two different directions, and a control unit ( 110 ) configured to determine a directional illuminance based on light intensities of the light received by the pair of light receivers ( 20, 22, 23, 24, 25 ).

First claim

1 . A light exposure sensing system for sensing light exposure of a user, comprising:
at least one wearable device; at least two light receivers oriented towards different directions orthogonal to each other and configured to receive light from these different directions, the light receivers being arranged on the at least one wearable device, and a control unit configured to determine light intensifies of light received from the at least two light receivers, wherein the control unit is further configured to determine a ratio of daylight to artificial light (X/Y) based on the light intensities of the light received from the at least two light receivers and based on the relation
X/Y ={(1/ f )* S 2− S 1}/{(1/ f )*( S 1− S 2)},

wherein the higher light intensity of the light intensities received by the at least two light receivers is denoted S 1 , the lower thereof is denoted S 2 , and f is the illuminance ratio of vertical to horizontal illuminance from the artificial light.

2 . The light exposure sensing system according to claim 1 , wherein the control unit is further configured to determine a directional illuminance of a user using a ratio of the light intensities of the light received by the at least two light receivers or on average or a weighted average of the light intensities of light received by the at least two light receivers.

3 . (canceled)

4 . (canceled)

5 . The light exposure sensing system according to claim 1 , wherein the light intensities are weighted differently based on an orientation of the wearable device and/or of the respective light receivers.

6 . The light exposure sensing system according to claim 1 , wherein the control unit is configured to determine receiver coverage, if the light intensities of light received by the at least two light receivers differ from each other more than a predetermined factor and/or is below a certain threshold value.

7 . (canceled)

8 . The light exposure sensing system according to claim 1 , wherein the light receivers have the same spectral sensitivity.

9 . (canceled)

10 . The light exposure sensing system according to claim 1 , wherein an orientation of the wearable device, is determined by assuming that the light receiver receiving the higher light intensity is closer to a horizontal orientation.

11 . The light exposure sensing system according to claim 1 , wherein an orientation of the wearable device, and/or a ratio of daylight to artificial light is determined based on the light intensities of light received by the at least two light receivers only, if a ratio of the light intensities differs from 1 more than a predetermined threshold value and/or if no receiver coverage is determined.

12 . The light exposure sensing system according to claim 1 , wherein the at east two light receivers configured to receive light from different directions are grouped in pairs and the control unit is configured to select a pair of light receivers from the plurality of pairs for determining the directional illuminance of a user.

13 . The light exposure sensing system according to claim 1 , wherein the wearable device and/or the system further includes at least one of:
an activity measuring unit for measuring body parameters of the user; an orientation for determining an orientation of the wearable device and/or of at least one of the light receivers; a storage unit for storing data; a display unit for displaying data; and a communication unit for data exchange.

14 . A lighting control system for ensuring a predetermined light exposure, including:
the light exposure sensing system according to claim 1 ; at least one lighting system; and a central control unit according to claim 2 , configured to use the determined directional illuminance of a user received from the light exposure sensing system as a feedback parameter to control the lighting system.

15 . A method for sensing light exposure of a user using two light receivers arranged in different directions on at least one wearable device, the method including:
receiving light from the different directions by the light receivers, and wherein a ratio of daylight to artificial light is determined based on the light intensities of light received from the different directions by the light receivers and based on the relation
X/Y ={(1/ f )* S 2− S 1}/{(1/ f )*( S 1− S 2)},

wherein the higher light intensity of the light intensities received by the at least two light receivers is denoted S 1 , the lower thereof is denoted S 2 , and f is the illuminance ratio of vertical to horizontal illuminance from the artificial light.

Assignees

• Philips Lighting Holding Bv

Inventors

• Gimenez Marina Cecilia
• Schlangen Lucas Josef Maria

Classifications

• G01J1/4204

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

• G01J1/4228

  arrangements with two or more detectors, e.g. for sensitivity compensation · CPC title

• G01J1/0233

  Handheld · CPC title

• A61N2005/0628

  including a radiation sensor · CPC title

• G01J1/0488

  with spectral filtering · CPC title