Miniaturized optical proximity sensor
An optical sensor, optical system, and proximity sensor are disclosed. An illustrative proximity sensor is disclosed to include a light source and a photodetector including a photo-sensitive area that receives incident light and converts the received incident light into an electrical signal. The light source and photodetector are positioned diagonally relative to one another, thereby enabling the devices to be positioned closer together on a body or substrate.
1. An optical sensing device, comprising:
a substrate;
a light source mounted on the substrate and configured to produce emitted light in response to receiving an electrical signal;
a photodetector mounted on the substrate and comprising a photo-sensitive area that receives incident light and converts the received incident light into an electrical signal;
a first optical element that is optically coupled to the light source and has a first centroid aligned on a first axis that is parallel with at least one side of the substrate and that intersects the photodetector; and
a second optical element that is optically coupled with the photodetector and has a second centroid offset from the first axis by an offset distance.
2. The optical sensing device of claim 1 , wherein the first axis substantially bisects the substrate into two equally-sized halves.
3. The optical sensing device of claim 1 , further comprising:
a cover that is substantially non-transparent to the emitted light, the cover having a first aperture and a second aperture.
4. The optical sensing device of claim 3 , wherein a center of the first aperture is substantially coincident with the first centroid of the first optical element and wherein a center of the second aperture is substantially coincident with the second centroid of the second optical element.
5. The optical sensing device of claim 4 , wherein the first optical element encapsulates the light source and wherein the first centroid of the first optical element is centered with respect to a first lens established on the first optical element.
6. The optical sensing device of claim 5 , wherein the second optical element encapsulates the photodetector and wherein the second centroid of the second optical element is centered with respect to a second lens established on the second optical element.
7. The optical sensing device of claim 5 , wherein the first aperture is larger than the second aperture.
8. The optical sensing device of claim 2 , wherein the first optical element comprises a first alignment structure that aligns the cover with respect to the substrate and that further mates with the cover and wherein the second optical element comprises a second alignment feature that also aligns the cover with respect to the substrate and that further mates with the cover.
9. The optical sensing device of claim 1 , wherein the offset distance is greater than zero and less than 30% of a longest dimension of the substrate.
10. The optical sensing device of claim 1 , further comprising:
a plurality of electrical connectors established on the substrate, wherein the plurality of electrical connectors are symmetrically disposed along the substrate with respect to the first axis.
11. A computing device, comprising:
a housing;
a sensing opening provided in the housing; and
an optical sensing module, comprising:
a substrate;
a light source mounted on the substrate and configured to produce emitted light in response to receiving an electrical signal;
a photodetector mounted on the substrate and comprising a photo-sensitive area that receives incident light and converts the received incident light into an electrical signal;
a first optical element that is optically coupled to the light source and has a first centroid aligned on a first axis that is parallel with at least one side of the substrate and intersects the photodetector; and
a second optical element that is optically coupled with the photodetector and has a second centroid offset from the first axis by an offset distance.
12. The computing device of claim 11 , wherein the light source comprises a light-emitting die, wherein a center of the light-emitting die is substantially aligned with the first centroid, wherein the photodetector is provided as an array of photo-sensitive pixels on an Integrated Circuit (IC) chip, and wherein a center of the array of photo-sensitive pixels is substantially aligned with the second centroid.
13. The computing device of claim 11 , wherein the optical sensing module further comprises a cover having a first aperture and a second aperture, wherein the first aperture is larger than the second aperture, wherein a center of the first aperture is substantially aligned with the first centroid, and wherein a center of the second aperture is substantially aligned with the second centroid.
14. The computing device of claim 11 , wherein the sensing opening is sized to enable light emitted by the light source to travel to an object and to enable light that reflects from the object to reach the photodetector.
15. An optical sensing device, comprising:
a substrate;
a light source mounted on the substrate and configured to produce emitted light in response to receiving an electrical signal;
a photodetector mounted on the substrate and comprising a photo-sensitive area that receives incident light and converts the received incident light into an electrical signal;
a first optical element that is optically coupled to the light source and has a first centroid aligned on a first axis that is parallel with at least one side of the substrate, wherein the first axis substantially bisects the substrate into two substantially equally-sized halves; and
a second optical element that is optically coupled with the photodetector and has a second centroid offset from the first axis by an offset distance.
16. The optical sensing device of claim 15 , wherein the first optical element comprises a first alignment structure that aligns the cover with respect to the substrate and that further mates with the cover and wherein the second optical element comprises a second alignment feature that also aligns the cover with respect to the substrate and that further mates with the cover.
17. The optical sensing device of claim 15 , wherein the offset distance is greater than zero and less than 30% of a longest dimension of the substrate.
18. The optical sensing device of claim 15 , wherein the light source comprises a light-emitting die, wherein a center of the light-emitting die is substantially aligned with the first centroid, wherein the photodetector is provided as an array of photo-sensitive pixels on an Integrated Circuit (IC) chip, and wherein a center of the array of photo-sensitive pixels is substantially aligned with the second centroid.
19. The optical sensing device of claim 15 , further comprising:
a cover having a first aperture and a second aperture, wherein the first aperture is larger than the second aperture, wherein a center of the first aperture is substantially aligned with the first centroid, and wherein a center of the second aperture is substantially aligned with the second centroid.
20. The optical sensing device of claim 15 , wherein the first optical element comprises a first lens having a first apex that is coincident with the first centroid and wherein the second optical element comprises a second lens having a second apex that is coincident with the second centroid.