Optical Collimator With Concave Micro Lenses For Homogeneous Illumination
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Solution Overview
Problem
Existing collimators with multiple light sources suffer from inhomogeneous illumination due to the lack of a homogeneous light source, leading to artefacts like light-dark contrasts, and current solutions such as diffusers or convex micro lenses are either costly, space-intensive, or result in light back-scattering and inhomogeneities.
Innovation Solution
A collimator design featuring concave micro lenses on optical surfaces, which prevents multiple image artefacts by having virtual focal planes away from the light source, maintaining scattering properties while being economical and compact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If diffusers or scattering lenses are arranged on the side of the collimator facing away from the light sources to achieve homogeneous illumination, then illumination uniformity is improved, but manufacturing cost and assembly complexity increase
Solution Approach 1:
The patent combines the homogeneous illumination function with the existing collimator structure by integrating micro-lenses directly into the collimator's optical surfaces. This merging eliminates the need for separate diffusers or scattering lenses, achieving uniform illumination while reducing manufacturing cost and assembly complexity.
Solution Approach 2:
The collimator's optical surfaces are designed to serve multiple functions: they act as both collimating elements and homogeneous illumination generators through the integrated micro-lenses. This multi-functionality eliminates the need for additional dedicated diffusion components.
2Illumination intensity
If the light exit surfaces of a collimator are formed as a diffuser by matting to achieve homogeneous illumination, then illumination uniformity is improved, but light back-scattering increases and efficiency decreases
Solution Approach 1:
Instead of matting the light exit surface to create diffusion (which causes back-scattering), the patent uses convex micro-lenses on the light exit surface. These micro-lenses refract light forward in multiple directions to achieve homogeneous illumination without back-scattering, inverting the conventional approach to diffusion.
3Illumination intensity
If convex micro lenses are arranged on the light exit surface to achieve homogeneous illumination, then illumination uniformity is improved, but multiple image artefacts and inhomogeneities occur in zoom lenses
Solution Approach 1:
The patent inverts the conventional approach by using concave micro-lenses instead of convex ones. The concave micro-lenses have virtual focal planes that prevent multiple image projection, eliminating the artefacts while maintaining the light-scattering effect for homogeneous illumination.
4Object-affected harmful factors
If the size of micro lenses is reduced to maintain light-scattering effect and decrease focal length, then multiple image artefacts are reduced, but production complexity and mold requirements increase
Solution Approach 1:
The patent changes the key parameter of micro-lens curvature from convex to concave. This parameter change fundamentally alters the optical behavior, creating virtual focal planes that prevent multiple image artefacts while allowing for larger, easier-to-manufacture lens dimensions with standard molding processes.
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 collimator achieves homogeneous illumination without additional costs or space constraints, reducing light back-scattering and inhomogeneities, ensuring uniform light distribution even with multiple light sources.
Implementation Method 1
concave micro lenses, which are formed on at least one of the optical surfaces... The focal planes of concave micro lenses, which can be projected to the far field, are virtual, unlike the focal planes of convex micro lenses, and are located on the side facing away from the light source
Implementation Method 2
optical collimator for focusing light by means of a plurality of optical surfaces, which are designed as light entry surfaces and/or light exit surfaces and/or reflection surfaces, each forming optical interfaces with a change in the optical density
Data Source
AI summary
The invention relates to an optical collimator for focusing light by means of a plurality of optical surfaces, which are designed as light entry surfaces and/or light exit surfaces and/or reflection surfaces, which form respective optical boundary surfaces with a change in the optical density. The aim of the invention is to propose a collimator by means of which homogeneous illumination is possible even if a plurality of light sources is used, the collimator having a compact design and being economical to produce. This aim is achieved, according to the invention, in that the collimator has a plurality of concave micro-lenses (3, 11), which are formed on at least one of the optical surfaces.