Sensors with LED Light Sources
AssigneeEndress+Hauser Conducta GmbH+Co. KG
InventorsAhmed Fathalla, Thilo Trapp
Life of this patent
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Abstract
An apparatus includes a light emitting diode, a reference detector, and a control unit. The light emitting diode (LED) is configured to emit light along a beam path. The reference detector is configured to generate a signal characterizing an intensity of light emitted from the LED. The control unit coupled to the LED and is configured to selectively vary a driving current applied to the LED in response to the light detected by the reference detector and to maintain a substantially constant intensity of light emitted by the LED. Related apparatus, systems, techniques and articles are also described.
Claims20
An apparatus comprising:
- a light emitting diode (LED) to emit light along a beam path;
- a reference detector to generate a signal characterizing an intensity of light emitted from the LED;
- and
- a control unit coupled to the LED to selectively vary a driving current applied to the LED in response to the light detected by the reference detector and to maintain a substantially constant intensity of light emitted by the LED.
A method for use with a sensor comprising a light emitting diode (LED) to emit light along a beam path, a reference detector to generate a signal characterizing an intensity of light emitted from the LED, and a control unit coupled to the LED, the method comprising:
- monitoring the signal generated by the reference detector;
- determining that the monitored signal indicates that an intensity of light emitted by the LED has fallen below a pre-defined lower threshold or that an intensity of light emitted by the LED exceeds a pre-defined upper threshold;
- and
- adjusting the driving current applied to the LED so that an intensity of light emitted by the LED falls within the pre-defined lower threshold and the pre-defined upper threshold as indicated by the monitored signal generated by the reference detector.
A non-transitory computer program product for use with a sensor comprising a light emitting diode (LED) to emit light along a beam path, a reference detector to generate a signal characterizing an intensity of light emitted from the LED, and a control unit coupled to the LED, the computer program product storing instructions, which when executed by at least one programmable data processors, result in operations comprising:
- monitoring the signal generated by the reference detector;
- determining that the monitored signal indicates that an intensity of light emitted by the LED has fallen below a pre-defined lower threshold or that an intensity of light emitted by the LED exceeds a pre-defined upper threshold;
- and
- adjusting the driving current applied to the LED so that an intensity of light emitted by the LED falls within the pre-defined lower threshold and the pre-defined upper threshold as indicated by the monitored signal generated by the reference detector.
Dependencies are inferred from the claim text.