Smoke detector and method of detecting smoke
First Claim
Patent Images
1. A smoke detector, comprising:
- a first light source configured to emit, from a first area thereon, light in a first wavelength range;
a first light sensor configured to detect the light in at least the first wavelength range;
a reflective surface configured to focus the light in the first wavelength range onto a second area that includes the first light sensor, wherein the second area is larger than the first area; and
a second light source configured to emit, from a third area thereon, light in a second wavelength range, wherein the reflective surface is configured to focus the light in the second wavelength range onto a fourth area that includes the first light sensor, and wherein the fourth area is larger than the third area.
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Abstract
A smoke detector that includes at least one image-forming reflective surface, at least one light source and at least one light sensor. In operation, at least one light source emits light from a first area thereon and the reflective surface focuses the light onto a second area that includes at least one light sensor, wherein the first area is smaller than the second area.
62 Citations
23 Claims
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1. A smoke detector, comprising:
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a first light source configured to emit, from a first area thereon, light in a first wavelength range; a first light sensor configured to detect the light in at least the first wavelength range; a reflective surface configured to focus the light in the first wavelength range onto a second area that includes the first light sensor, wherein the second area is larger than the first area; and a second light source configured to emit, from a third area thereon, light in a second wavelength range, wherein the reflective surface is configured to focus the light in the second wavelength range onto a fourth area that includes the first light sensor, and wherein the fourth area is larger than the third area. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of monitoring smoke concentration, the method comprising:
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emitting light in a first wavelength range from a first area on a first light source; focusing the light in the first wavelength range onto a second area, wherein the second area is larger than the first area and includes a first light sensor; detecting how much of the light in the first wavelength range reaches the first light sensor; emitting light in a second wavelength range from a third area on a second light source; focusing the light in the second wavelength range onto a fourth area, wherein the fourth area is larger than the third area and includes the first light sensor; and detecting how much of the light in the second wavelength range reaches the first light sensor. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 22, 23)
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21. A method of monitoring smoke concentration, comprising:
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emitting light, on an intermittent basis, in a first wavelength range from a first area on a first light source; focusing the light in the first wavelength range onto a second area, wherein the second area is larger than the first area and includes a first light sensor; detecting how much of the light in the first wavelength range reaches the first light sensor; recording a first plurality of measurement values at times when the first light source is emitting the light in the first wavelength; recording a second plurality of measurement values at times when the first light source is idle; subtracting the second plurality of measurement values from the first plurality of measurement values to obtain a plurality of measured values; and averaging the plurality of measured values to obtain a single measured value.
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Specification