DTIR Collimator Microlenses for Homogeneous Light Distribution
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Solution Overview
Problem
Existing collimators fail to achieve an ideal light distribution with constant or homogeneous intensity within a predeterminable light cone, free of reflections and local intensity maxima/minima, and have complex geometries.
Innovation Solution
A DTIR collimator with light-refracting structures on the light exit surface, such as concave and/or convex microlenses, ensures each beam exits with a small cone angle, preventing local intensity variations and achieving a homogeneous light distribution through light mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional collimators (lenses, TIR collimators, CPC collimators) are used to collimate light, then light can be directed into a cone, but the light distribution is not homogeneous and shows local intensity maxima and minima in the form of reflections, lines or rings
Solution Approach 1:
The invention applies local quality by introducing light-refracting structures (microlenses) at specific locations on the light exit surface of the collimator. These microlenses have different optical properties than the surrounding surface, creating local variations in light refraction that collectively eliminate unwanted reflections and intensity variations. Each microlens acts as a local optical element with tailored properties to achieve homogeneous light distribution across the entire beam.
Solution Approach 2:
The light-refracting structures serve as an intermediary between the collimating optics and the final light output. These microlenses mediate the light path by refracting individual light beams, preventing direct reflections from reaching the observer and redistributing light intensity to eliminate hot spots and dark zones. The intermediary structures transform the non-uniform light distribution into a homogeneous pattern.
2Illumination intensity
If TIR collimators with converging lens and surrounding reflector are used, then light can be collimated, but the geometry becomes complex due to different light entry and exit surfaces for lens and reflector
Solution Approach 1:
The invention merges the functions of the converging lens and reflector into a single integrated collimator body with uniform geometry. Instead of having separate components with different surfaces, the light guide structure combines refraction and total internal reflection functions in one element, allowing both light entry and exit surfaces to have the same geometric configuration. This simplifies manufacturing and assembly while maintaining collimation performance.
Solution Approach 2:
The collimator structure achieves universality by using a single geometric design for both light entry and exit surfaces. The same surface geometry is used throughout the light guide, allowing the structure to perform multiple optical functions (refraction, total internal reflection, light distribution) without requiring different surface configurations for different functions. This multi-functional design reduces complexity.
3Illumination intensity
If straight-walled or CPC collimators with flat light entry and exit surfaces are used, then light distribution can be achieved, but side walls require convex design which increases device volume
Solution Approach 1:
The invention addresses the volume issue by moving the light distribution function from the spatial dimension (convex side walls requiring large volume) to the surface dimension (microlenses on the exit surface). Instead of using convex side walls to redirect light, the patent uses a flat or simplified light guide with microlenses on the exit surface to achieve homogeneous light distribution. This dimensional shift allows for a more compact overall design while maintaining light distribution capabilities.
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 provides a compact design with etendue-limited light distribution, ensuring a homogeneous light intensity both near and far from the source, reducing undesired reflections and intensity variations.
Implementation Method 1
the light exit surface (4) of the DTIR collimator according to the claims comprises light-refracting structures. The light-refracting structures on the light exit surface (4) of the DTIR collimator cause each light beam to leave the light exit surface (4) with a small cone angle
Implementation Method 2
a totally reflective side wall (3) connecting the light entry surface (2) to the light exit surface (4)
Implementation Method 3
so-called dielectric total internal reflection collimators (DTIR collimators)
Data Source
AI summary
A collimator (1) for collimating light uses a plurality of optical surfaces each forming optical boundary surfaces with a change in the optical density. The collimator (1) has a substantially flat light entry surface (2), a convex light exit surface (4) and a totally reflective side wall (3) connecting the light entry surface (2) to the light exit surface (4). A portable lighting device is provided having such a collimator. In order to provide a collimator and a portable lighting device having a collimator which achieves a better light distribution, the light exit surface of the collimator has light-refracting structures (5).