Droplet sensor
AssigneeMitsumi Electric Co., Ltd.
InventorsYuya Kawasaki, Hideo Kurosawa
Life of this patent
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Abstract
A droplet sensor has an optical cover with a curved surface that forms a part of a spheroid, a light source positioned at a first focal point of an ellipse, the first focal point facing the curved surface, and a photodetector positioned at a second focal point of the ellipse. The ellipse has an eccentricity determined such that the curved surface has an effective detection area that satisfies conditions for total internal reflection at an interface with a gas and that does not satisfy the conditions for total internal reflection at an interface with a liquid.
Claims14
A droplet sensor comprising:
- an optical cover having a curved surface that forms a part of a spheroid;
- a light source positioned at a first focal point of an ellipse, the first focal point facing the curved surface;
- and
- a photodetector positioned at a second focal point of the ellipse,
- wherein the ellipse has an eccentricity determined such that the curved surface has an effective detection area that satisfies conditions for total internal reflection at an interface with a gas and that does not satisfy the conditions for total internal reflection at an interface with a liquid, and
- wherein the optical cover is a transparent solid with respect to a wavelength of the light source, the transparent solid having a first spherical space and a second spherical space at a bottom, the light source being positioned inside the first spherical space and the photodetector being positioned inside the second spherical space.
A droplet sensor comprising:
- an optical cover having a curved surface that forms a part of a spheroid;
- a light source positioned at a first focal point of an ellipse, the first focal point facing the curved surface;
- and
- a photodetector positioned at a second focal point of the ellipse,
- wherein the ellipse has an eccentricity determined such that the curved surface has an effective detection area that satisfies conditions for total internal reflection at an interface with a gas and that does not satisfy the conditions for total internal reflection at an interface with a liquid,
- wherein the optical cover is a transparent solid with respect to a wavelength of the light source,
- wherein the transparent solid has a cavity at the second focal point of the ellipse, and
- the photodetector is provided in the cavity, an interface between the cavity and the transparent solid is a transmitting and scattering surface.
Dependencies are inferred from the claim text.