Light Guide Color Mixing With Wavelength-Dependent Output Modifiers
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Solution Overview
Problem
Current lighting solutions for transportation interiors, such as electroluminescent film and organic light emitting diodes (OLEDs), are expensive and have low reliability, while inorganic LEDs require external optical systems to achieve homogeneous color, leading to non-homogeneous color effects due to spatial separation of LED chips, which is unsuitable for thin, space-constrained environments.
Innovation Solution
A lighting device comprising a light guide with wavelength-dependent modification features, such as colored ink spots, optically coupled with RGB LED packages to modify light intensity and achieve homogeneous color output, and optionally using a diffuser and opaque mask to mix light sources, ensuring uniformity across a large surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If spatially separated LED chips are used to generate different wavelengths, then color versatility is improved, but color homogeneity deteriorates
Solution Approach 1:
A light guide acts as an intermediary medium to transport light from spatially separated LED chips. The light guide distributes light from multiple wavelengths across a larger area, allowing the separate light sources to overlap and mix, thereby achieving color homogeneity while maintaining the versatility of using separate LED chips for different colors
Solution Approach 2:
The invention transitions from a two-dimensional arrangement of LED chips on a circuit board to a three-dimensional light distribution system using a light guide. By introducing the light guide thickness dimension and using wavelength-dependent modifiers at specific depths, the system achieves color homogeneity through spatial mixing in the third dimension while maintaining chip separation for color versatility
2Stability of the object's composition
If external optical systems are used to achieve homogeneous color, then color uniformity is improved, but device thickness increases
Solution Approach 1:
The invention merges the optical functions of light transport, color mixing, and homogenization into a single integrated light guide structure. Instead of using separate external optical components, the light guide combines these functions through internal wavelength-dependent modifiers, achieving color uniformity without increasing overall device thickness
Solution Approach 2:
The invention changes the optical parameters of the light guide by introducing wavelength-dependent modifiers with specific absorption characteristics. By adjusting the absorption coefficients at different wavelengths and positioning modifiers at optimized depths, the system achieves color homogeneity while maintaining a thin profile suitable for transportation applications
3Length of moving object
If RGB LED packages are closely packed to reduce optical system depth, then device thickness is reduced, but power density and cost per area increase
Solution Approach 1:
The invention uses the light guide thickness dimension to distribute light from spaced-apart LED packages. By transporting light through the light guide and using wavelength-dependent modifiers at specific depths, the system achieves color homogeneity with reduced LED package density, thereby lowering power density and cost per area while maintaining acceptable device thickness
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 provides a thinner, more reliable, and cost-effective homogeneous color lighting solution that maintains uniformity over a large surface area, addressing the non-homogeneous color issues of existing technologies and meeting the requirements of transportation industries.
Implementation Method 1
Both light-guide designs exploit the effects of refraction caused by two materials having different refractive index. In particular, a light-guide transports light from one location to another, by exploiting the effects of total internal reflection experienced by the light propagating within the material when it encounters a boundary surrounding the material
Implementation Method 2
one or more wavelength dependent modification features arranged to modify the intensity of at least one of the two or more light outputs
Implementation Method 3
A schematic representation of second type of RGB LED package known in the art is provided in FIG. 1(b) and depicted generally by reference numerals 8
Data Source
AI summary
A lighting device includes a light guide having a light output surface, one or more LED packages having two or more spatially separated LED chips, and two or more wavelength dependent modification features located on the output surface of the light guide. Each wavelength dependent modification features is configured to modify the intensity of light from one or more of the LED chips to provide homogeneous colored light.