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US 11,961,379 B2Granted
Measurement chamber for mounting on a smoke detection unit, having a light trap according to the principle of a fresnel stepped lens
AssigneeSiemens Schweiz AG
InventorUlrich Kuhn-Matysiak
Life of this patent
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Abstract
Various embodiments of the teachings herein include a measurement chamber for a smoke detection unit of a smoke detector. The measurement chamber may include: at least a passage for smoke to be detected; and a measurement chamber cover with angular light trap structures on an inside of the measurement chamber. The angular light trap structures are shaped to follow the compact-design principle of a Fresnel stepped lens.
Claims12
A method for producing a cylindrical measurement chamber for a smoke detection unit of a smoke detector, the method comprising:
- forming a measurement chamber cover using an injection molding process;
- combining the measurement chamber cover with a complementary, essentially hollow or hollow cylindrical smoke inlet part to make up the measurement chamber;
- wherein the measurement chamber cover comprises a spherical component with introduced angular concentric light trap structures shaped to form Fresnel light trap structures following the compact-design principle of a Fresnel stepped lens;
- wherein the Fresnel light trap structures of the spherical measurement chamber cover, after the injection molding process, are free of undercuts;
- wherein the spherical measurement chamber cover is formed into an essentially flat measurement chamber cover using a deformation process;
- wherein the Fresnel light trap structures are shaped in the direction of the Fresnel axis and undercuts form;
- wherein a Fresnel point, after the measurement chamber as a whole has been produced and after it has been attached to a smoke detection unit provided, is located at a light exit of a light emitter of the smoke detection unit.
4 more elements
A smoke detection module comprising:
- a light emitter arranged on a circuit carrier;
- a spectrally matched photosensor in a scattered light arrangement;
- and
- a measurement chamber attached to the smoke detection unit;
- the measurement chamber comprising:
- at least a passage for smoke to be detected;
- a measurement chamber cover with angular light trap structures on an inside of the measurement chamber, wherein the angular light trap structures are shaped to follow the compact-design principle of a Fresnel stepped lens;
- a diaphragm to limit the respective emitted light beam located optically downstream of the light emitter;
- and
- a further diaphragm to limit the respective optical reception area connected optically upstream of the photosensor;
- wherein the optical limits are dimensioned in such a way that only a proportion of the area of the part of the measurement chamber cover illuminated by the respective light emitter is in a range of 10% to 40% in the respective optical detection range of the at least one photosensor.
8 more elements
Dependencies are inferred from the claim text.