Apparatus and methods to measure optical density
AssigneePharyx, Inc.
InventorsHarry Lee, Kevin Shao-Kwan Lee
Life of this patent
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Abstract
The present invention provides apparatus and methods for measuring the optical density of a fluid by measuring the light transmission through a reconfigurable optical path. The optical path is reconfigured by the deflection of an elastic membrane wherein the optical path length through the fluid is determined by the position of the membrane relative to a fixed surface. The optical density can be determined from two measurements with different optical path lengths through the fluid.
Claims13
An apparatus for measuring the optical density of a fluid comprising:
- a light source;
- a light detector;
- an elastic membrane;
- a first deformable portion of the elastic membrane with a first side fluidically isolated from a second side that is in contact with the fluid;
- a first surface facing the second side of the first deformable portion of the elastic membrane with at least a portion of the first surface in contact with the fluid;
- a second surface facing the first side of the first deformable portion of the elastic membrane;
- and
- a reconfigurable optical path from the light source to the light detector that passes through the fluid in at least one configuration of the reconfigurable optical path;
- wherein:
- the optical path length through the fluid is determined by the position of the first deformable portion of the elastic membrane relative to the first surface;
- in a first configuration of the reconfigurable optical path the elastic membrane substantially contacts the second surface and the fluid is included in the reconfigurable optical path;
- and
- in a second configuration of the reconfigurable optical path the elastic membrane substantially contacts the first surface and the fluid is substantially excluded from the reconfigurable optical path.
A method to measure optical density of a fluid comprising the steps of:
- a) configuring a first configuration of a reconfigurable optical path from a light source to a light detector that includes a first optical path length through the fluid defined by a first surface and a second side of a deformable portion of an elastic membrane, wherein the deformable portion of the elastic membrane is deflected in a first position where a first side of the deformable portion of the elastic membrane substantially contacts a second surface;
- b) activating the light source and the light detector;
- c) measuring the quantity of light transmission, T1, through the reconfigurable optical path, configured in the first configuration, from the light source to the light detector that includes the first optical path length through the fluid;
- d) configuring a second configuration of the reconfigurable optical path from the light source to the light detector that substantially excludes the fluid, wherein the deformable portion of the elastic membrane is deflected in a second position where the second side of the deformable portion of the elastic membrane substantially contacts the first surface;
- and
- e) measuring the quantity of light transmission, T2, through the reconfigurable optical path, configured in the second configuration, from the light source to the light detector that substantially excludes the fluid.
Dependencies are inferred from the claim text.