LED Illumination Module Uniform Chromaticity
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Solution Overview
Problem
Solid state lighting systems for general illumination face challenges in maintaining consistent white light hue and brightness across multiple panels due to variations in LED intensity and placement, leading to non-uniform color and increased inventory costs.
Innovation Solution
A linear illumination module design featuring a printed circuit board with metameric pairs of LEDs, optical films, and a reflective sheet that recycle and mix light to achieve uniform chromaticity and luminosity, utilizing a combination of brightness enhancement films and diffusers to ensure consistent light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple solid state lighting panels are connected together to form a lighting system, then the illumination area is increased, but the hue of white light varies from panel to panel due to variations in LED intensity and placement
Solution Approach 1:
A metamerically equivalent white light source is introduced as an intermediary to combine with the red, green and blue light emitting devices. This intermediary source provides a consistent white light baseline that compensates for variations in LED intensity and placement, ensuring uniform hue across multiple panels while maintaining the benefits of expanded illumination area.
2Reliability
If red, green and blue light emitting devices are used to generate white light, then the color rendering index is improved, but the chromaticity varies due to variations in LED intensity and placement
Solution Approach 1:
The intensity parameters of the red, green and blue light emitting devices are adjusted and optimized in combination with the metamerically equivalent white light source. By changing and balancing these intensity parameters, the system achieves both high color rendering index and consistent chromaticity across multiple panels, resolving the contradiction between color quality and uniformity.
3Manufacturing precision
If extensive binning is performed to select panels with consistent chromaticity, then the hue uniformity is improved, but the manufacturing complexity and inventory costs increase
Solution Approach 1:
The metamerically equivalent white light source acts as a compensating intermediary that eliminates the need for extensive binning procedures. By providing a consistent white light baseline, it allows panels with varying LED characteristics to still achieve uniform hue, thereby reducing manufacturing complexity and inventory management requirements while maintaining high hue uniformity.
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 solution achieves high uniformity in light output, reducing the need for extensive binning and inventory management, while allowing for flexible adjustment of light characteristics to maintain desired hues and brightness levels.
Implementation Method 1
The optical film, the reflective sheet and the sidewalls of the support member are configured to recycle light emitted by the LEDs by reflecting some light in the optical cavity back into the optical cavity and transmitting some light emitted by the LEDs out of the optical cavity.
Data Source
AI summary
An illumination module includes a longitudinal support member including a base portion and a pair of sidewalls extending from the base portion that together define a channel that extends in a longitudinal direction. A printed circuit board (PCB) on the base portion extends in the longitudinal direction within the channel. A plurality of light emitting diodes (LEDs) are on the PCB in a linear array. A reflective sheet is within and extends across the channel, and includes a plurality of holes that correspond with locations of the LEDs on the PCB, and the LEDs are positioned in the holes. An optical film extends across the channel above the reflective sheet and defines an optical cavity between the reflective sheet and the optical film. The optical film, the reflective sheet and the sidewalls of the support member recycle light in the optical cavity.