Faceted Mixing Rod Surface for Uniform Light Without Multiple Imaging
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Solution Overview
Problem
Existing mixing rods for inhomogeneous light sources suffer from high light losses, inadequate mixing quality, and potential multiple imaging of the light source, which are not effectively addressed by current designs.
Innovation Solution
A mixing rod with a faceted, convex or concave light-emitting surface and a polygonal cross-section, combined with a shape transition and homogenization section, minimizes light losses and ensures effective mixing without multiple imaging by shifting the virtual image of the light source away from the lens focus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mixing rod with grooved surfaces is used to ensure uniform mixing of the light beam, then the mixing quality is improved, but light losses increase
Solution Approach 1:
The light-emitting surface is divided into multiple facets (e.g., 6-12 facets) that segment the emitted light into different directions. This segmentation achieves uniform mixing and eliminates kaleidoscopic patterns without requiring grooved surfaces that cause high light losses, thereby resolving the contradiction between mixing quality and energy efficiency.
Solution Approach 2:
The light-emitting surface is designed with a convex or concave curvature instead of flat grooved surfaces. This curved faceted surface redirects light uniformly in all directions while maintaining high transmission efficiency, achieving both good mixing quality and low light losses.
2Device complexity
If a mixing rod with a flat light-emitting surface is used, then the structure is simple, but multiple imaging of the light source occurs resulting in kaleidoscopic luminous intensity distribution
Solution Approach 1:
The light-emitting surface is given a convex or concave curvature instead of being flat. This curvature, combined with faceting, redirects light rays to eliminate multiple imaging and kaleidoscopic patterns while maintaining structural simplicity and avoiding complex grooved surface designs.
Solution Approach 2:
The faceted surface creates asymmetric light redirection paths that prevent the formation of symmetric kaleidoscopic patterns. The combination of facets and curvature ensures uniform light distribution without the harmful multiple imaging effects.
3Manufacturing precision
If the mixing rod length is increased to achieve good mixing, then the mixing quality is improved, but the device length increases
Solution Approach 1:
The convex or concave curvature of the light-emitting surface creates immediate light redirection and mixing at the exit point, eliminating the need for long propagation distances. This achieves uniform mixing quality in a compact rod length, resolving the contradiction between mixing quality and device length.
Solution Approach 2:
The faceted surface segments light into multiple directions immediately at the exit, creating rapid mixing without requiring long rod lengths. This segmented light redirection achieves effective mixing in a compact structure.
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 efficient, low-loss mixing of light beams with improved luminance distribution and uniformity, allowing for adjustable beam widening without additional optical elements.
Implementation Method 1
A mixing rod with a faceted, convex or concave light-emitting surface and a polygonal cross-section, combined with a shape transition and homogenization section, minimizes light losses and ensures effective mixing without multiple imaging by shifting the virtual image of the light source away from the lens focus.
Implementation Method 2
Mixing rods for blending a beam of light are known, for example, from US 2007/0024971 A1. These mixing rods are intended to produce a beam of light with an approximately circular cross-section and a substantially uniform luminous intensity distribution, as well as a uniform illuminance distribution at the light exit point, i.e., a mixing of the light in both direction and location.
Implementation Method 3
The cross-sectional shape of these mixing rods can be circular, elliptical, oval, rectangular, or in the form of a pentagon, hexagon, or other polygon. The mixing rod can be conical between a light-entry surface and a light-emission surface.
Data Source
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AI summary
The present invention relates to a mixing rod for mixing a beam of light from an inhomogeneous light source and to a lighting device comprising such a mixing rod. The mixing rod (1) is formed from an elongated transparent body with a light-entry surface (2), a lateral surface (3), and a light-emission surface (4). The light-emission surface or the light-entry surface is substantially convex or concave. The light-emission surface or the light-entry surface is characterized by being formed from several smooth facets.