Apparatus, method and system for monitoring and maintaining light levels at target area for lighting system
First Claim
1. A method of sensing lumen depreciation or loss in light output from a light source wherein the light source is operatively mounted in a lighting fixture comprising one or more of a light source holder, electrical supply means, and optical surface including but not limited to a reflective surface or lens, and comprising:
- a. sensing light quantity of the light source externally from the lighting fixture;
b. comparing the sensed light quantity to a reference light quantity related to other than lamp lumen depreciation (LLD); and
c. taking an action if the comparison exceeds a pre-determined offset, wherein the action comprises;
(i) removing dirt, debris, dust, and/or foreign objects from the lighting fixture if the lighting fixture has LDD;
(ii) sensing again the light quantity of the light source externally from the lighting fixture;
(iii) making a second comparison of the sensed light quantity to the reference light quantity; and
(iv) taking a second action if the second comparison exceeds a pre-determined offset, wherein the second action comprises generating a signal and communicating the signal to another component.
1 Assignment
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Accused Products
Abstract
A method of sensing magnitude of lumen depreciation not only of a lamp of a lighting fixture, but other factors, by sensing a relative light level external of the lighting fixture to derive not only lamp lumen depreciation but total lumen depreciation from the fixture. An apparatus of monitoring light level of one or more lighting fixtures comprises a sensor positioned external of the lighting fixture(s), a comparator adapted to compare a measured actual lumen output signal from the sensor to a pre-set reference or threshold lumen output value. An error signal is generated by the comparator if the comparison indicates actual lumen output to have dropped below the reference or threshold lumen output. An alarm or communication can be actuated by the error signal to instruct corrective action to ensure relatively constant light levels to be maintained for the lighting system over time, thus providing ongoing assurance to the end user of proper system operation.
66 Citations
32 Claims
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1. A method of sensing lumen depreciation or loss in light output from a light source wherein the light source is operatively mounted in a lighting fixture comprising one or more of a light source holder, electrical supply means, and optical surface including but not limited to a reflective surface or lens, and comprising:
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a. sensing light quantity of the light source externally from the lighting fixture; b. comparing the sensed light quantity to a reference light quantity related to other than lamp lumen depreciation (LLD); and c. taking an action if the comparison exceeds a pre-determined offset, wherein the action comprises;
(i) removing dirt, debris, dust, and/or foreign objects from the lighting fixture if the lighting fixture has LDD;
(ii) sensing again the light quantity of the light source externally from the lighting fixture;
(iii) making a second comparison of the sensed light quantity to the reference light quantity; and
(iv) taking a second action if the second comparison exceeds a pre-determined offset, wherein the second action comprises generating a signal and communicating the signal to another component. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An apparatus for sensing lumen depreciation from a plurality of lighting fixtures comprising:
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a. a light quantity sensor adapted to measure light quantity of the plurality of lighting fixtures externally of the lighting fixtures; and b. a light quantity sensor circuit operatively connected to the light quantity sensor adapted to generate a signal or alarm if measured light quantity by the light quantity sensor falls below a reference quantity for a predefined period of time. - View Dependent Claims (22, 23, 24, 25)
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26. A system of sensing lumen depreciation from a plurality of lighting fixtures adapted to collectively illuminate a target area comprising:
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a. a plurality of light sources in the lighting fixtures, each light source having an LLD characteristic and each fixture having at least one optical surface; b. at least one light quantity sensor external of the lighting fixtures adapted to measure light quantity of at least one of the lighting fixtures relative to a reference quantity, the at least one light quantity sensor configured to restrict the light quantity measurement to a predetermined range of wavelengths and to a predetermined field of view relative to the target area; c. a circuit operatively connected to each light quantity sensor adapted to generate a signal if the measured light quantity differs from the reference quantity by a predetermined amount or more. - View Dependent Claims (27, 28, 29, 30, 31, 32)
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Specification