Controllable optical sensing
An optical sensing device for using light to locate objects or features in a field of view comprises a light source; a controllable lens having two states and being controllable between them, for example a multifocal lens having two or more foci for focusing light from the light source; and a sensor able to sense light reflected from an object, to determine information of the object. The use of two or more foci adds dynamic range to optical sensing to allow for reliable detection over a wide range of distances.
1. An optical sensing device comprising:
a light source;
a multi-focal lens having a plurality of foci configured to focus light from the light source into a space at a plurality of focal points related to the plurality of foci, wherein the multi-focal lens comprises a lens surface shaped to provide an apodized surface function;
a sensor configured to sense focused light of the light source reflected from an object in the space to sense the object or features of the object; and
an adjustable shutter placed in relation to the multi-focal lens configured to be altered for controlling amounts of light from the light source falling over different regions of the shaped surface of the multi-focal lens to vary amounts of energy of light at the plurality of focal points.
2. The optical sensing device of claim 1 , further comprising a light structuring unit for adding structure to light of the light source, for recognition by the optical sensing device.
3. The optical sensing device of claim 1 , wherein the space is a three-dimensional space and the plurality of foci comprises foci at two different distances.
4. The optical sensing device of claim 3 , wherein one of the plurality of foci is a focus at infinity.
5. The optical sensing device of claim 2 , wherein the light structuring unit is one member of the group consisting of a diffractive pattern generator, an amplitude mask, a phase mask, and a patterned film.
6. The optical sensing device of claim 1 , wherein the multi-focal lens is a diffractive lens having diffractive steps, each step having a height, and wherein respective heights are varied over the surface to provide the apodized surface function.
7. The optical sensing device of claim 1 , wherein the adjustable shutter is altered to provide a beam expansion setup of the optical sensing device.
8. An optical sensing method comprising:
shining light from a light source on a multi-focal lens having a plurality of foci configured to focus light from the light source into a space at a plurality of focal points related to the plurality of foci, wherein the multi-focal lens comprises a lens surface shaped to provide an apodized surface function;
sensing focused light of the light source reflected from an object in the space to sense the object or features of the object; and
controlling amounts of light from the light source falling over different regions of the shaped surface of the multi-focal lens to vary amounts of energy of light at the plurality of focal points.
9. The optical sensing method of claim 8 , further comprising adding structure to light of the light source for sensing the focused light of the light source reflected from the object.
10. The optical sensing method of claim 8 , wherein the multi-focal lens is a diffractive lens having diffractive steps, each step having a height, and wherein respective heights are varied over the surface to provide the apodized surface function.
11. The optical sensing method of claim 8 , further comprising
directing light from the light source sequentially between the different regions of the shaped surface.
12. The optical sensing method of claim 8 , wherein one of the plurality of foci is at infinity.