LED Light Source Adaptive Color Control
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Solution Overview
Problem
Existing LED-based light sources face challenges in quickly and accurately adjusting color location and intensity due to variations in environmental conditions and LED aging, with integrated light sensors often capturing light with a different hue than emitted light, leading to aesthetic and structural issues.
Innovation Solution
A light source with semiconductor light-emitting elements, a light guide, and an electronic control unit that adjusts brightness based on sensor signals, using adaptive integration time intervals to ensure accurate color adjustment, even with low light intensities, and a reflective element to enhance efficiency and minimize visual interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an integrated light sensor is used on the LED chip, then color location and intensity can be measured, but the captured light may have a different hue than the emitted light due to arrangement differences
Solution Approach 1:
A light guide is introduced as an intermediary component between the LED chip and the light sensor. The light guide conducts the emitted light from the LED chip to the light sensor, ensuring that the sensor captures the actual emitted light rather than light with altered hue characteristics. This mediator resolves the hue discrepancy caused by direct integration arrangements.
2Measurement precision
If the sensor is arranged in the illuminated room, then the emitted light can be measured, but this causes structural and aesthetic issues
Solution Approach 1:
The light sensor is nested within the LED module structure itself, specifically positioned to receive light through the light guide that is already part of the LED assembly. This nested arrangement allows the sensor to measure the emitted light without requiring separate external sensor housings or complex structural modifications to the illumination system.
3Measurement precision
If a light sensor is used to measure color location, then reproducible color can be achieved, but the adjustment response time is slow due to integration time requirements
Solution Approach 1:
The integration time of the light sensor is made dynamically adjustable based on the operational requirements. During normal operation, a shorter integration time is used for rapid color adjustment response. When high precision measurement is needed and time permits, the integration time can be extended to improve measurement accuracy. This dynamic parameter adjustment resolves the contradiction between response speed and measurement precision.
4Area of stationary object
If the light guide is used to distribute light, then a larger light-emitting surface is achieved, but the light intensity may be reduced
Solution Approach 1:
The light guide is designed with spatially varying properties to maintain high intensity across the extended surface. Different sections of the light guide can have different optical characteristics, such as varying refractive indices, scattering properties, or reflective coatings, to optimize light distribution and maintain intensity levels appropriate for each local region of the extended light-emitting surface.
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
Enables rapid and precise control of color location and intensity, minimizing visual differences between light sources and maintaining high efficiency while allowing the light sensor to be placed without interfering with the illumination field.
Implementation Method 1
a light guide (3) into which the light emitted by the semiconductor light-emitting elements (21, 22, 23, 24) is injected, at least partially, and which is configured so that the light injected by the semiconductor light-emitting elements (21, 22, 23, 24) exits laterally from the light guide (3)
Implementation Method 2
the light guide is configured so that the light injected by the semiconductor light-emitting elements (21, 22, 23, 24) exits laterally from the light guide (3)
Implementation Method 3
and a reflective element (9) arranged so as to reflect part of the light that is laterally emitted from the light guide (3)
Data Source
AI summary
A light source is provided that includes at least two semiconductor light-emitting elements that emit light of different color, a light guide, an electronic control unit, and a light sensor. The light emitted by the elements is injected, at least partially, into the light guide and exits laterally from the light guide. The brightness of the elements can be adjusted by the electronic control unit. The light sensor is arranged to receive the light injected by the elements and laterally exiting from the light guide. The electronic control unit accumulates sensor signals from the light sensor over an integration time interval and compares the accumulated signals with a target value or range to determine a difference, changes a brightness of the elements in response to the difference, and changes the integration time interval in response to the difference or to a change in the target value.