Reference switch architectures for noncontact sensing of substances
This relates to systems and methods for measuring a concentration and type of substance in a sample at a sampling interface. The systems can include a light source, optics, one or more modulators, a reference, a detector, and a controller. The systems and methods disclosed can be capable of accounting for drift originating from the light source, one or more optics, and the detector by sharing one or more components between different measurement light paths. Additionally, the systems can be capable of differentiating between different types of drift and eliminating erroneous measurements due to stray light with the placement of one or more modulators between the light source and the sample or reference. Furthermore, the systems can be capable of detecting the substance along various locations and depths within the sample by mapping a detector pixel and a microoptics to the location and depth in the sample.
1 . A light measurement system for measuring concentration of a substance, the system comprising:
a light source configured to emit light into a sample;
a detector;
a first optics unit configured to:
receive first light returned from a first location of the sample and focus the received first light on a plane; and
receive second light from a second location of the sample and focus the received second light on the plane;
an aperture unit positioned at the plane and between the first optics unit and the detector, the aperture unit defining:
a first opening configured to selectively transmit a portion of the received first light; and
a second opening configured to selectively transmit a portion of the received second light; and
a second optics unit positioned between the aperture unit and the detector, the second optics unit configured to:
receive the portion of the received first light from the aperture unit and direct the portion of the received first light to the detector; and
receive the portion of the received second light from the aperture unit and direct the portion of the received second light to the detector.
2 . The light measurement system of claim 1 , wherein:
the detector comprises a first detector pixel and second detector pixel; and
the second optics unit is configured to:
direct the portion of the received first light to the first detector pixel; and
direct the portion of the received second light to the second detector pixel.
3 . The light measurement system of claim 2 , further comprising a third optics unit positioned between the second optics unit and the detector, wherein the third optics unit comprises:
a first optics configured to receive the portion of the received first light from the second optics unit and direct the portion of the received first light to the first detector pixel; and
a second optics configured to receive the portion of the received second light from the second optics unit and direct the portion of the received second light to the second detector pixel.
4 . The light measurement system of claim 3 , wherein:
the third optics unit comprises a microoptics unit having an array of micro lenses;
the first optics is a first micro lens of the array of micro lenses; and
the second optics is a second micro lens of the array of micro lenses.
5 . The light measurement system of claim 1 , wherein the aperture unit is configured to selectively transmit light based on one or more pathlengths of received light, an angle of incidence of received light, or a combination thereof.
6 . The light measurement system of claim 5 , wherein:
the first opening comprises a first aperture size that is configured to selectively transmit light having a first pathlength and block light having a second pathlength; and
the second opening comprises a second aperture size, different from the first aperture size, that is configured to selectively transmit light having the first pathlength and block light having the second pathlength.
7 . The light measurement system of claim 6 , wherein:
the first aperture size is configured to transmit light from a first depth of the sample; and
the second aperture size is configured to transmit light from a second depth of the sample.
8 . The light measurement system of claim 1 , further comprising a controller operable coupled to the detector, wherein the controller is configured to determine a concentration of a substance in the sample based on the portion of the received first light measured by the detector and the portion of the received second light measured by the detector.
9 . A light measurement system, comprising:
a light source configured to emit light into a sample;
a detector comprising a first detector pixel and a second detector pixel;
a first optics unit configured to:
receive first light returned from a first location of the sample and focus the received first light at on a plane; and
receive second light from a second location of the sample and focus the received second light on the plane;
an aperture unit positioned at the plane and between the first optics unit and the detector, the aperture unit defining:
a first opening configured to selectively transmit a portion of the received first light; and
a second opening configured to selectively transmit a portion of the received second light; and
a microoptics unit positioned between the aperture unit and the detector, wherein the microoptics unit comprises:
a first optics configured to receive the portion of the received first light from the first opening and direct the portion of the received first light to the first detector pixel; and
a second optics configured to receive the portion of the received second light from the second opening and direct the portion of the received second light to the second detector pixel.
10 . The light measurement system of claim 9 , further comprising a second optics unit positioned between the aperture unit and the microoptics unit, the second optics configured to:
receive the portion of the received first light from the aperture unit and direct the portion of the received first light to the first optics; and
receive the portion of the received second light from the aperture unit and direct the portion of the received second light to the second optics.
11 . The light measurement system of claim 10 , wherein the first optics unit and the second optics unit each comprise an objective lens.
12 . The light measurement system of claim 9 , wherein:
the first optics is a first micro lens of an array of micro lenses; and
the second optics is a second micro lens of the array of micro lenses.
13 . The light measurement system of claim 12 , wherein:
the microoptics unit comprises a substrate; and
each microlens in the array of micro lenses is attached to the substrate.
14 . The light measurement system of claim 12 , wherein:
the microoptics unit comprises an array of microlenses; and
microlenses of the array of micro lenses are separated by opaque sections.
15 . The light measurement system of claim 9 , wherein the first opening has a different size from the second opening.
16 . A system for measuring concentration of a substance in a sample, the system comprising:
a light source configured to emit light into the sample;
a detector comprising a first detector pixel and a second detector pixel;
a plurality of output regions located at an interface of the system and configured to:
receive first light returned from a first location of the sample and focus the received first light at on a plane; and
receive second light from a second location of the sample and focus the received second light on the plane;
an aperture unit positioned at the plane and between the plurality of output regions and the detector, the aperture unit defining:
a first opening configured to selectively transmit a portion of the received first light; and
a second opening configured to selectively transmit a portion of the received second light; and
an optics unit positioned between the aperture unit and the detector, the optics unit comprising:
a first optics configured to receive the portion of the received first light from the first opening and direct the portion of the received first light to the first detector pixel; and
a second optics configured to receive the portion of the received second light from the second opening and direct the portion of the received second light to the second detector pixel.
17 . The system of claim 16 , wherein:
the detector comprises a plurality of detector pixels;
the optics unit comprises a plurality of microoptics; and
each microoptics of the plurality of microoptics is optically coupled to a detector pixel of the plurality of detector pixels.
18 . The system of claim 17 , wherein each micro-optic-detector pixel pair is associated with a different sampling location.
19 . The system of claim 16 , further comprising a first objective lens positioned between the plurality of output regions and the aperture unit, and configured to focus the first light and the second light on the plane of the aperture unit.
20 . The system of claim 19 , further comprising a second objective lens positioned between the aperture unit and the optics unit and configured to focus light receive from the aperture unit on the optics unit.