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US 8,614,550 B2Granted
Supervision for a light display device
AssigneeSimplexGrinnell LP
InventorJoseph D. Farley
Life of this patent
Estimating the term…
Abstract
A device and method may include, in a display device, emitting visible light in a humanly imperceptible manner and sensing said light to verify operation of the display device.
Claims13
A light display device comprising:
- a LED configured to emit light in response to power supplied thereto;
- a photodetector disposed adjacent the LED, said photodetector configured to detect an intensity of light emitted from the LED and to generate an electrical signal that corresponds to such intensity;
- and
- a control circuit connected to the LED and the photodetector, the control circuit configured to initiate a flash test to determine the operability of the LED, wherein during the flash test said control circuit is configured to activate the LED for an amount of time so that the light from the activated LED is imperceptible to a human, said control circuit further configured to receive the electrical signal from said photodetector and to determine whether the LED is operational.
1 more element
A method comprising:
- initiating a flash test to determine the operability of a LED in a light display device, wherein the flash test comprises activating the LED for an amount of time that the light from the activated LED is imperceptible to a human;
- and
- determining whether the LED failed to operate based on the intensity of light emitted by the LED.
Dependencies are inferred from the claim text.