Dimmable LED Reading Light Unit Potentiometer Interface
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Solution Overview
Problem
Existing passenger transportation vehicles, such as airplanes and ships, face challenges in replacing halogen lights with LED lights due to the need for costly and cumbersome adaptations in power supply units, and the requirement for dimmable lighting that maintains selected light intensity.
Innovation Solution
A dimmable LED reading light unit is designed with a potentiometer input, a load current source, a current controller, and an electronic measuring and control unit, which allows for parallel connection to the potentiometer, enabling the determination of potentiometer position and control of LED current to achieve desired light intensity without altering the power supply unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If halogen lights are replaced by LED lights, then power consumption is reduced and light yield is improved, but the existing power supply units require costly and cumbersome adaptations
Solution Approach 1:
The LED reading light unit performs self-measurement of the potentiometer position by internally generating a test current and measuring the resulting voltage drop across the potentiometer. This self-service approach eliminates the need for external power supply adaptations, as the unit independently determines the dimming setting without requiring modified power supply circuitry.
Solution Approach 2:
The patent introduces an intermediary measurement process where a test current is used as a mediator to indirectly determine the potentiometer position. By measuring the voltage drop caused by this intermediary current, the system obtains the dimming information without directly interfacing with or modifying the existing power supply unit.
2Measurement precision
If the potentiometer position is measured by connecting an ammeter in series, then the measurement is direct, but the ammeter influences the circuit operation and requires series connection which complicates installation
Solution Approach 1:
The patent uses a test current as an intermediary to indirectly measure the potentiometer position. Instead of directly measuring current through the potentiometer (which would require series connection), the test current flows through the potentiometer and the resulting voltage drop is measured. This intermediary voltage measurement approach avoids the need for series connection while maintaining measurement precision.
Solution Approach 2:
The patent replaces the mechanical/electrical approach of series connection with an electronic field-based measurement. By utilizing voltage measurement (an electric field quantity) instead of direct current measurement (which requires breaking the circuit for series connection), the system achieves the same measurement goal without the complexity of series connection.
3Ease of manufacture
If the existing potentiometer is used for dimming control, then component replacement is minimized and costs are reduced, but the potentiometer position must be accurately determined to maintain dimming functionality
Solution Approach 1:
The LED reading light unit performs self-measurement of the potentiometer position by internally generating a test current and measuring the resulting voltage drop. This self-service capability ensures accurate determination of the potentiometer position without requiring external measurement devices or complex calibration procedures, thereby maintaining dimming functionality while using the existing potentiometer.
Solution Approach 2:
The system implements a feedback mechanism where the measured voltage drop is used to determine the potentiometer position, which then informs the control of the LED dimming. This feedback loop ensures that the dimming functionality accurately reflects the potentiometer setting, maintaining precise control while reusing the existing component.
Data Source
AI summary
A dimmable LED reading light unit, in particular for a passenger transportation vehicle, such as an airplane, a bus or a ship, comprises an input which is connectable to a potentiometer that outputs a direct voltage having a voltage intensity corresponding to a selected potentiometer position; a load current source being configured to generate a predetermined load current; a current controller providing an operating current for operating at least one LED; and an electronic measuring and control unit; wherein the load current source and the current controller are connected to the input in parallel.