Light Mixing Lamp Using Fly-Eye Lenses for Uniform Illumination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lighting devices using solid state light sources, such as LEDs, face challenges in achieving uniform light distribution and high color rendering index, particularly due to thermal management issues and color shadowing caused by non-uniform collimation of light beams from different LEDs.
Innovation Solution
An illumination device comprising a solid state light source array, collimating lenses, fly-eye lenses, and Fresnel lenses, which collimate and homogenize light to produce uniform output, avoiding color shadowing and enhancing color rendering index through a structured arrangement of lenses and optical mixing rods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple LEDs are packaged together in an array at the focus of a Fresnel lens to get parallel light beam, then optical power is improved, but thermal management becomes difficult due to thermal interference between LEDs
Solution Approach 1:
The patent divides the light mixing process into two stages: first collimating light from each LED individually using separate collimators, then mixing the collimated beams in the far field. This segmentation allows each LED to be thermally managed independently while still achieving high optical power through array configuration.
2Device complexity
If lights from different color LEDs are collimated by different collimators and mixed in the far field, then device complexity is reduced, but light uniformity deteriorates due to color shadowing and color rings
Solution Approach 1:
The patent introduces optical mixing rods with specific length-to-diameter ratios (L/D ≥ 3) to change the mixing parameters. The rods provide sufficient interaction length for diffuse reflection and multiple internal reflections, transforming the collimated beams into uniformly mixed light while maintaining device simplicity.
Solution Approach 2:
The optical mixing rods act as intermediaries between the collimated light beams and the final mixed output. The rods' internal surfaces facilitate multiple reflections and diffuse scattering, enabling thorough color mixing without requiring complex lens arrangements.
3Ease of operation
If collimated light from different color LEDs is mixed in the far field, then ease of operation is improved, but color rendering index deteriorates due to incomplete color mixing
Solution Approach 1:
The optical mixing rods serve as intermediary elements that facilitate thorough color mixing through multiple internal reflections and diffuse scattering. This ensures complete color blending for high color rendering index while maintaining the simple far-field mixing geometry for ease of operation.
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 device achieves improved light uniformity and high color quality, effectively addressing the limitations of existing technologies by ensuring uniform mixing of light on the exit surface and allowing for adjustable power and color control.
Implementation Method 1
each collimating lens being aligned with a solid state light source to collimate the light emitted from the solid state light source into near parallel light
Implementation Method 2
the collimated light emitted from the collimating lens array passes through the first and second fly-eye lens successively before being output from the illumination device
Implementation Method 3
a pair of Fresnel lenses, including a first Fresnel lens and a second Fresnel lens, wherein the first Fresnel lens' focus is close to or overlapped with the second Fresnel lens' focus
Data Source
AI summary
An light mixing illumination device includes an array (1) of a plurality of solid state light sources, and an array (2) of a plurality of collimating lenses, each collimating lens being aligned with a solid state light source to collimate the light emitted from the solid state light source into a near parallel light; and a pair of first (5) and second (6) fly-eye lenses, wherein the collimated light from the collimating lens array (2) passes through the first and second fly-eye lens successively.