ILLUMINATION DEVICE FOR AN OPTICAL SENSOR, OPTICAL SENSOR AND METHOD FOR CONTROLLING AN ILLUMINATION DEVICE
An illumination device for an optical sensor is provided. The illumination device includes a plurality of light sources and a control circuit. The control circuit is configured to control the plurality of light sources to entirely illuminate a field of illumination in a first operation mode. The control circuit is further configured to control the plurality of light sources to illuminate at least one subfield of the field of illumination in a second operation mode.
1 . An illumination device for an optical sensor, comprising:
a plurality of light sources; and
a control circuit configured to:
control the plurality of light sources to entirely illuminate a field of illumination in a first operation mode; and
control the plurality of light sources to illuminate at least one subfield of the field of illumination in a second operation mode.
2 . The illumination device of claim 1 , wherein the control circuit is further configured to control the plurality of light sources to not entirely illuminate the field of illumination in the second operation mode.
3 . The illumination device of claim 1 , further comprising:
an optical device comprising at least one focusing optical device and at least one diffusing optical device;
wherein the at least one diffusing optical device is configured to diffuse light emitted by at least one of the plurality of light sources in the first operation mode, and
wherein the at least one focusing optical device is configured to focus light emitted by at least one of the plurality of light sources in the second operation mode.
4 . The illumination device of claim 1 , wherein the control circuit is further configured to selectively switch on and off a first subset of the plurality of light sources in the first operation mode to entirely illuminate the field of illumination and to selectively switch on and off a second subset of the plurality of light sources in the second operation mode to illuminate the at least one subfield.
5 . The illumination device of claim 4 , wherein the control circuit comprises:
a first driver circuit connected to the first subset of the plurality of light sources and configured to switch on the first subset in the first operation mode; and
a second driver circuit connected to the second subset of the plurality of light sources and configured to switch on the second subset in the second operation mode.
6 . The illumination device of claim 4 , further comprising:
an optical device comprising at least one focusing optical device and at least one diffusing optical device;
wherein the at least one diffusing optical device is configured to diffuse light emitted by at least one of the plurality of light sources in the first operation mode,
wherein the at least one focusing optical device is configured to focus light emitted by at least one of the plurality of light sources in the second operation mode, and
wherein at least one of the at least one focusing optical device faces at least one of the light sources of the second subset, and wherein at least one of the at least one diffusing optical device faces at least one of the light sources of the first subset.
7 . The illumination device of claim 6 , wherein the at least one of the at least one focusing optical device protrudes from the optical device towards the at least one of the light sources of the second subset.
8 . The illumination device of claim 6 , wherein the at least one of the at least one diffusing optical device protrudes from the optical device towards the at least one of the light sources of the first subset.
9 . The illumination device of claim 1 , wherein the plurality of light sources are arranged in an array.
10 . The illumination device of claim 9 , wherein the light sources of the first subset and the light sources of the second subset are distributed irregularly over the array.
11 . The illumination device of claim 10 , wherein a concentration of the light sources of the first subset in a center area of the array is higher than in a boundary area of the array.
12 . The illumination device of claim 4 , wherein the light sources of the first subset are arranged in a first array and the light sources of the second subset are arranged in a second array, wherein the first array and the second array are spatially interleaved.
13 . The illumination device of claim 3 , wherein the optical device is placed in parallel with the plurality of light sources.
14 . An optical sensor, comprising:
an illumination device comprising:
a plurality of light sources; and
a control circuit configured to:
control the plurality of light sources to entirely illuminate a field of illumination in a first operation mode; and
control the plurality of light sources to illuminate at least one subfield of the field of illumination in a second operation mode; and
a photo-sensitive circuit configured to generate measurement data based on reflected light from the field of illumination.
15 . A method for controlling an illumination device, comprising:
controlling a plurality of light sources of the illumination device to entirely illuminate a field of illumination in a first operation mode; and
controlling the plurality of light sources to illuminate at least one subfield of the field of illumination in a second operation mode.
16 . The method of claim 15 , wherein controlling the plurality of light sources in the second operation mode includes controlling the plurality of light sources to illuminate a portion of the field of illumination less than an entirety of the field of illumination.