Spatially Varying Microlens Diffuser for Uniform LED Illumination
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Solution Overview
Problem
Conventional diffusers in lighting systems fail to effectively homogenize light from multiple light sources with varying spacings, leading to non-uniform illumination and visibility of light sources, especially in applications like LCD TVs and LED backlights.
Innovation Solution
The development of diffusers with substrates featuring arrays of microlenses that vary in dimensions, shapes, and optical properties as a function of the spacing between light sources, incorporating microvariations (on the order of microns) and macrovariations (on the order of millimeters), which provide controlled spatial luminance variation and obscure light sources when viewed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional uniform diffuser is used, then the structure is simple and easy to manufacture, but the light homogenization is insufficient and light sources remain visible
Solution Approach 1:
The patent applies local quality by varying the microlens parameters (size, shape, spacing, refractive index) across different regions of the diffuser substrate. Each region is optimized for its specific position relative to light sources, creating spatially non-uniform optical properties that achieve superior light homogenization while addressing the visibility of individual light sources.
Solution Approach 2:
The diffuser is segmented into multiple zones with different microlens configurations. Each zone contains microlenses with specific parameters tailored to the local lighting conditions and spacing, allowing independent optimization of different regions to collectively achieve uniform illumination across the entire surface.
2Loss of energy
If the diffuser is placed close to light sources to improve efficiency, then energy loss is reduced, but light source visibility and non-uniformity increase
Solution Approach 1:
The patent implements local quality by designing different microlens regions with varying optical properties. Regions closer to light sources have microlenses optimized for collecting and redistributing intense localized light, while regions farther away have different configurations. This spatial variation allows the diffuser to operate close to light sources for energy efficiency while maintaining illumination uniformity across the entire output surface.
3Adaptability or versatility
If multiple light sources with varying spacing are used, then the lighting system is versatile and adaptable, but homogenization becomes difficult to achieve
Solution Approach 1:
The patent addresses varying light source spacing by implementing local quality through spatially varying microlens parameters. The diffuser substrate contains regions with different microlens sizes, shapes, and spacing that correspond to different light source configurations. This allows the same diffuser to effectively homogenize light from multiple light sources regardless of their specific spacing, maintaining adaptability while achieving uniform illumination.
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
These diffusers achieve improved light homogenization and reduced visibility of light sources, enhancing illumination uniformity and energy efficiency by adapting to the spacing between multiple light sources, such as CCFL bulbs and LEDs, thereby addressing the issue of non-uniformity in lighting systems.
Implementation Method 1
the at least one feature provides more refraction from the array of microlenses adjacent the plurality of light sources compared to remote from the plurality of light sources
Implementation Method 2
the at least one feature provides more reflection, such as by total internal reflection, from the array of microlenses adjacent the plurality of light sources compared to remote from the plurality of light sources
Data Source
AI summary
A diffuser is configured to diffuse radiation from multiple light sources. The diffuser includes a substrate having optical structures that exhibit both microvariations and macrovariations along the substrate. For example, an array of microlenses may be provided that include at least one feature that varies as a function of the spacing between the light sources. Lighting systems using these diffusers may also be provided.