Color-Mixing Optical System Using Light Guide Rod and Convergent Lens
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Solution Overview
Problem
Current outdoor imaging display panels and lighting systems face challenges in achieving high light intensity and uniform color mixing without significant size and cost increases, as they require precise alignment of individual LEDs and suffer from light loss due to scattering and complex light guide designs.
Innovation Solution
A compact optical system using a commercially available RGB LED with a light guide rod having a constant or gradually increasing cross-section, where the light exit surface coincides with the focus of a converging lens, ensuring efficient mixing and bundling of light without color differences or fringes, achieved through geometric design and minimal length of the light guide rod.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a complex optical fiber with ridges and concave indentations is used for color mixing, then color mixing capability is improved, but manufacturing cost and device complexity increase significantly
Solution Approach 1:
The patent extracts the light guiding function from complex structured optical fibers and implements it through a simple cylindrical or prismatic light guide in combination with a collimator. This separates the color mixing function (handled by the LED array itself) from the light guiding function, allowing each component to be simple while achieving overall system performance.
Solution Approach 2:
The patent divides the lighting system into distinct functional segments: the LED array for light generation and color mixing, the collimator for beam shaping, and the simple light guide for light transmission. This segmentation allows each component to be optimized independently with simple geometry, avoiding the need for complex integrated optical fibers.
2Shape
If a cylindrical light guide with a long curved path is used to direct light, then light direction control is improved, but the construction length and space requirements increase
Solution Approach 1:
The patent applies a collimator before the light guide to pre-shape and direct the light beam. This preliminary action of collimation reduces the need for long curved light guide paths, as the light is already directed towards the desired trajectory before entering the light guide, thereby shortening the overall construction length.
3Illumination intensity
If individual red, green and blue LEDs are used with lens tips for high light intensity, then light intensity is improved, but alignment precision requirements and manufacturing complexity increase
Solution Approach 1:
The patent merges the three separate LED light sources (red, green, blue) into a single integrated LED array that emits light simultaneously. This combination, coupled with the collimator design, ensures that light from all three LEDs is collected and directed together, achieving high intensity while eliminating the need for precise individual alignment of multiple LEDs with lens tips.
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
This solution allows for uniform color mixing and bundling of light with minimal loss, maintaining intensity and direction, while being cost-effective and space-efficient, thus addressing the limitations of existing systems in outdoor displays and lighting.
Implementation Method 1
a light guide rod (2) arranged in front of it and a collecting lens (5). The light guide rod extends perpendicular to its entry surface, the length of which is a multiple of the diameter of the entry surface
Implementation Method 2
the light exit surface coincides with the focus of a converging lens
Data Source
Figure 1~2
Figure 3~5
AI summary
The invention relates to an optical system for focused light emission, which can be used as a pixel capable of full color in a grid assembly mainly in variable message signs and outdoor electronic display boards. Among other things a commercially available full-color LED in SMD design having a red, a green, and a blue LED crystal acts as the light source (1). Directly in front of the light source lies the inlet surface (3) of a light-guiding rod (2), said inlet surface having approximately the same size. The light-guiding rod (2) has a constant cross-section and a jacket surface made of planes adjacent to each other at sharp edges. The light-guiding rod captures the light substantially completely and completely mixes the different colors and brightnesses very efficiently without the aid of scattering. The light output (4) of the light-guiding rod (2) lies at the focus of a convergent lens (5), which focuses the exiting light. The convergent lens (5) and the light-guiding rod (2) can be combined as one piece. The light exiting the light-guiding rod can be further adapted in the distribution of said light by optically active surfaces or scattering structures that overlie the convergent lens.