Asymmetric Annular Collimating Lens for Compact Solid State Lighting
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Solution Overview
Problem
Existing lighting devices with solid state lighting elements face challenges in achieving high collimation efficiency while maintaining a compact size, as traditional collimating lenses become bulky with increased collimation requirements, and doughnut lenses compromise collimation performance due to large apertures.
Innovation Solution
An asymmetric annular collimating lens structure with a single inner reflective prism and a plurality of outer Fresnel-type prisms is used, optimizing the volume distribution to enhance collimation efficiency and compactness, allowing for improved luminous peak power and optical efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional collimating lenses are used to achieve high collimation, then collimation performance is improved, but device volume increases
Solution Approach 1:
The lens is divided into multiple functional zones: a central refractive zone for primary collimation, surrounded by annular reflective zones for light redirection. This segmentation allows each zone to contribute differently to collimation, achieving high collimation performance while reducing the overall volume required compared to a traditional single-zone lens of equivalent performance.
Solution Approach 2:
The invention utilizes multi-dimensional optical paths by combining refractive indexing in the central zone with total internal reflection in annular zones. This dimensional approach to light control enables compact lens design while maintaining high collimation, as light is managed through multiple spatial dimensions rather than requiring a single large refractive element.
2Volume of moving object
If doughnut lenses are used to reduce volume, then device compactness is improved, but collimation performance deteriorates due to large aperture
Solution Approach 1:
Different zones of the lens are assigned different optical properties: the central zone provides refractive collimation while annular zones provide reflective control. This local differentiation of optical quality allows the lens to achieve high collimation performance despite a compact doughnut configuration, as each local region is optimized for its specific function.
Solution Approach 2:
The lens employs an asymmetric annular configuration with a central aperture rather than a symmetric solid doughnut shape. This asymmetric design with the central opening allows reduced aperture size while maintaining effective collimation through the combined refractive-reflective optical paths, resolving the trade-off between compactness and performance.
3Power
If multiple SSL elements are used to increase luminous output, then total luminous flux is improved, but device complexity and thermal management difficulty increase
Solution Approach 1:
Multiple SSL elements are merged into a single integrated lens assembly where all elements share a common optical path through the central refractive zone and annular reflective zones. This merging approach increases total luminous output while reducing device complexity, as the unified lens structure replaces what would otherwise require multiple separate collimating lenses and housing structures.
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 achieves superior collimated light intensities with fewer solid state lighting elements, improving energy efficiency and facilitating easier thermal management, while maintaining a compact form factor and homogeneous luminous output.
Implementation Method 1
The collimating lens 10 comprises a central refractive portion 12 surrounded by a total internal reflection prism 14
Implementation Method 2
The collimating lens 10 comprises a central refractive portion 12 surrounded by a total internal reflection prism 14
Data Source
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AI summary
Disclosed is a lighting device (1) including a lens (200, 300) comprising an annular collimating structure (100) having a central axis of symmetry (202), said structure comprising a light exit surface (105) and an intermediate region (120) in between an inner region (110) proximal to said axis and an outer region (130) distal to said axis, wherein one of the inner region and outer region consists of a single prism (112) extending from the light exit surface by a first height (h1) and the other of the inner region and outer region comprises a plurality of prisms (132) extending from the light exit surface by a maximum second height (h2), wherein the first height is at least the maximum second height and the intermediate region has an intermediate region surface (120′) separated from the light exit surface by a maximum further height (h3) that is smaller than the first height; and a plurality of solid state lighting elements (20) arranged in a circular pattern on a carrier surface (25) such that the solid state lighting elements are aligned with and facing the intermediate region surface (120′); and wherein the annular collimating structure is made of a material having a refractive index such that the first region is a refractive region and the single prism and the plurality of prisms each reflect light emitted by the solid state lighting elements towards the light exit surface. A luminaire including such a lighting device is also disclosed.