Gas detection using differential path length measurement
AssigneeAnalog Devices, Inc.
InventorShrenik Deliwala
Life of this patent
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Abstract
Device for improving an optical detecting smoke apparatus and implementing thereof. Apparatus and methods for detecting the presence of smoke in a small, long-lasting smoke detector are (disclosed. Specifically, the present disclosure shows how to build one or more optimized blocking members in a smoke detector to augment signal to noise ratio. This is performed while keeping the reflections from the housing structure to a very low value while satisfying all the other peripheral needs of fast response to smoke and preventing ambient light. This allows very small measurements of light scattering of the smoke particles to be reliable in a device resistant to the negative effects of dust. In particular, geometrical optical elements, e.g., cap and optical defection elements, are disclosed.
Claims20
An optical differential path length gas detector comprising:
- a light source producing a first light;
- a light filter disposed proximally to the light source;
- a first conic-section optic configured to split the light into two pathways, a second and third light, respectively, after having passed through the light filter;
- a first photodetector configured to measure the second light, wherein the first photodetector is configured to have a shorter pathlength than the third light;
- and
- a second conic-section optic configured to direct the third light to a second photodetector;
- wherein the second photodetector is configured to measure the third light.
An optical differential path length gas detector comprising:
- a first light source producing a first light;
- a first light filter disposed proximally to the first light source;
- a first conic-section optic configured to direct the first light towards a third conic-section optic;
- a second light source producing a second light;
- a second light filter disposed proximally to the second light source;
- a second conic-section optic configured to direct the second light towards the third conic-section optic;
- and
- a photodetector configured to measure the first and second light;
- wherein, the third conic-section optic is configured to direct the first and second light toward the photodetector.
A method for optical differential path length gas detector comprising:
- producing a first light at a first light source;
- filtering the first light at a light filter disposed proximally to the light source;
- splitting, at a first conic-section optic, the filtered first light into two pathways, a second and third light, respectively;
- measuring the second light at a first photodetector, wherein the first photodetector is configured to have a shorter pathlength than the third light;
- directing, at a second conic-section optic, the third light to a second photodetector;
- and
- measuring the third light at the second photodetector.
Dependencies are inferred from the claim text.