Led end of life optical comparator and methods for determining led light fixture end of life
AssigneeAstronics Corporation
InventorJeffery Basil LENDARO
Life of this patent
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Abstract
The present invention provides methods and devices for determining end of life of a light fixture by comparing the light output of a control LED of the fixture with the light output of an illumination LED of the fixture. The control LED is energized for a short period of time for the purpose of measuring its light output. The illumination LED is energized for the duration of time of the light fixture itself. In this way, the amount of degradation of the illumination LED can be determined by comparison with the control LED. If the light output of the illumination LED falls below a threshold level, actions may be take, such as, for example, sounding an alarm.
Claims18
A method of determining end of life of an LED light fixture, comprising the steps of:
- energizing a control LED;
- registering, using a sensor, the light output of the control LED;
- de-energizing the control LED;
- energizing an illumination LED;
- registering, using the sensor, the light output of the illumination LED;
- and
- comparing the output of the illumination LED to a threshold value based on the output of the control LED.
An LED light fixture, comprising:
- a controller;
- an illumination LED in electrical communication with the controller and selectively operable;
- a control LED in electrical communication with the controller;
- a photo-diode configured to detect the output of the control LED and the output of one of the illumination LED;
- and
- wherein the controller is programmed to:
- receive an illumination signal;
- energize the control LED and detect the output of the control LED using the photo-diode;
- determine a threshold output level based on the output of the control LED;
- de-energize the control LED;
- energize the illumination LED;
- detect the output of one of the illumination LED using the photo-diode;
- and
- compare the output of the illumination LED to the threshold output value.
An LED light fixture, comprising:
- a photo-diode;
- a control LED proximate to the photo-diode such that the light output of the control LED is detectable by the photo-diode, and where the control LED is configured to operate for a pre-determined length of time;
- an illumination LED proximate to the photo-diode such that the light output of the illumination LED is detectable by the photo-diode, and wherein the illumination LED is configured to operate after operation of the control LED;
- a comparator configured to compare the detected output of the at least one illumination LED to a threshold value based on the detected output of the control LED.
Dependencies are inferred from the claim text.