LED Self-Calibration via Feedback Loop for Optical Drift
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Solution Overview
Problem
Existing LED lighting devices struggle to maintain accurate luminous flux and color temperature due to changes in the optical system during assembly or over time, such as contamination on the dome of the lighting device.
Innovation Solution
A controllable LED lighting device is equipped with a self-calibration procedure that adjusts the optical compensation value based on measured luminous flux and detector forward voltage, allowing the device to compensate for changes in the optical system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the LED lighting device uses a fixed optical compensation value from factory calibration, then the initial luminous flux and color temperature are accurate, but the values drift over time due to optical system changes such as dome contamination
Solution Approach 1:
The patent implements a feedback mechanism where the detector continuously monitors the actual luminous flux output of the LED emitter. The control circuit compares the measured luminous flux against the expected value and dynamically adjusts the optical compensation value to compensate for drift caused by optical system changes such as dome contamination, ensuring long-term measurement accuracy
Solution Approach 2:
The lighting device performs self-calibration using its own integrated detector and control circuitry. The system automatically detects optical system degradation and adjusts its own compensation values without requiring external calibration equipment or manual intervention, enabling the device to maintain accuracy autonomously over time
2Measurement precision
If the optical compensation value is adjusted frequently to maintain accuracy, then luminous flux measurement precision is maintained, but the complexity of the calibration system increases
Solution Approach 1:
The patent combines the calibration function with the normal operational detection function. The same detector used for monitoring luminous flux during operation is also used for calibration purposes. The control circuit integrates both calibration and operational control functions, eliminating the need for separate calibration hardware and reducing system complexity
Solution Approach 2:
The detector and control circuit serve multiple functions: they monitor luminous flux during normal operation, detect optical system degradation, perform self-calibration, and adjust compensation values. This multi-functionality reduces the need for dedicated calibration components and simplifies the overall system architecture
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The self-calibration procedure ensures that the LED lighting device maintains consistent luminous flux and color temperature, even after assembly or over time, by accurately adjusting for changes in the optical system.
Implementation Method 1
a detector configured to generate a detector signal in response to detected light
Implementation Method 2
The emitter may emit light through the dome and the detector may generate the detector signal in response to a portion of the light that is emitted by the emitter and reflected off the dome to the detector
Data Source
AI summary
A lighting device, such as a controllable light-emitting diode (LED) light source, may execute a self-calibration procedure to compensate for changes in an optical system of the lighting device that may have occurred after an initial factory calibration procedure. The lighting device may include an emitter, a detector that generates a detector signal in response to detected light, a memory that stores a curve defining an optical compensation value with respect to a measured forward voltage of the detector, and a control circuit configured to receive a measured value of a luminous flux of the light emitted by the emitter that may be determined in response to the detector signal and based on the optical compensation value. The control circuit may adjust the curve defining the optical compensation value in response to a difference between the measured value and an expected value of the luminous flux.