US4221485A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical smoke detector
Assignee: Honeywell Inc
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Filing: 1979-06-04
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Granted: 1980-09-09
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Expires: 1999-06-04
Abstract
Abstract An optical smoke detector having a smoke sensing chamber comprising a point source of light mounted on the middle of a photodetector, the source of light transmitting in a forward direction and away from the photodetector and further having the point source of light located at the center of curvature of a spherical reflector. During normal standby periods when there are no smoke particles in the chamber to scatter the light, the light is transmitted to the spherical reflector and reflected back to the source without falling on the photodetector. In the presence of smoke the light is scattered and falls on the photodetector to indicate the presence of the smoke.
Inventors
- 👤 Richard G. Schulze
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:21
CPC Classifications
G; G08; G08B; G08B17/00; G08B17/10; G08B17/103; G08B17/107; G01; G01N; G01N21/00; G01N21/17; G01N21/47; G01N21/49; G01N21/53; G08B17/11; G08B17/113
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
150 words
Optical smoke detector apparatus comprising: a smoke sensing chamber having air inlet and outlet means; a light emitter; an optical sensor in said chamber having a face comprising a light receiver, said light emitter being mounted on said sensor, said light receiver being of a relatively large area with respect to said light emitter; spherical light reflector means mounted in said chamber such that the light emitter is located at the center of curvature of the spherical light reflector means; the light being directed from said light emitter onto said light reflecting means and not onto said light receiver, whereby the light directed on said spherical light reflecting means is reflected back to said light emitter without falling on said light receiver; and whereby in the presence of smoke in said chamber, light is scattered thereby, and falls on said light receiving portion to indicate the presence of said smoke.
Claim 2
Dependent Claim
150 words
Optical smoke detector apparatus comprising: a smoke sensing chamber having air inlet and outlet means; a light emitter; an optical sensor in said chamber having a face comprising a light receiver, said light emitter being mounted on said sensor, said light receiver being of a relatively large area with respect to said light emitter; spherical light reflector means mounted in said chamber such that the light emitter is located at the center of curvature of the spherical light reflector means; the light being directed from said light emitter onto said light reflecting means and not onto said light receiver, whereby the light directed on said spherical light reflecting means is reflected back to said light emitter without falling on said light receiver; and whereby in the presence of smoke in said chamber, light is scattered thereby, and falls on said light receiving portion to indicate the presence of said smoke.
Claim 3
Dependent Claim
56 words
The apparatus in accordance with claim 1 wherein said light receiving portion is substantially planar, with said light emitting portion comprising an LED (light emitting diode) mounted in the middle of said light receiving portion, the LED constructed to emit light into a forward direction and does not direct illumination back onto the light receiving portion.
Claim 4
Dependent Claim
28 words
The apparatus in accordance with claim 1 wherein said light emitting portion is an infrared source and said optical sensor light receiving portion is sensitive to the infrared.
Claim 5
Dependent Claim
130 words
An improved smoke sensing chamber for an optical smoke detector apparatus comprising: a smoke sensing chamber; spherical mirror means in said chamber; light source means mounted at the center of curvature of said mirror means in said chamber; light detector means surrounding said light source means in said chamber; the light from said source being forward directed onto said spherical mirror means and not onto said surrounding light detector means, whereby the light directed on said mirror means is reflected back to said source without falling on said light detector means; and whereby in the presence of smoke in said chamber the light and the reflected light is scattered by the smoke particles and the scattered light falls on the light detector means to indicate the presence of said smoke.
Claim 6
Dependent Claim
130 words
An improved smoke sensing chamber for an optical smoke detector apparatus comprising: a smoke sensing chamber; spherical mirror means in said chamber; light source means mounted at the center of curvature of said mirror means in said chamber; light detector means surrounding said light source means in said chamber; the light from said source being forward directed onto said spherical mirror means and not onto said surrounding light detector means, whereby the light directed on said mirror means is reflected back to said source without falling on said light detector means; and whereby in the presence of smoke in said chamber the light and the reflected light is scattered by the smoke particles and the scattered light falls on the light detector means to indicate the presence of said smoke.
Claim 7
Dependent Claim
16 words
The apparatus in accordance with claim 4 wherein said light source means is an infrared source.
Claim 8
Dependent Claim
19 words
The apparatus in accordance with claim 5 wherein said infrared source is a gallium arsenide light emitting diode (LED).
Claim 9
Dependent Claim
18 words
The apparatus in accordance with claim 5 wherein said light detector means is sensitive to the infrared source.
References Cited (Backward Citations)
US3226703A
Cited
US4072421A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-09-09 | 1984-03-10 | 1984-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-09 | 1988-03-10 | 1988-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-09 | 1992-03-10 | 1992-09-09 | $7700.00 | Window Closed / Lapsed |