Concave Lens Structure for Uniform LED Light Distribution
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Solution Overview
Problem
Existing light emitting modules face challenges in achieving uniform light distribution over large areas due to alignment issues between LEDs and lenses, leading to bright and dark portions, and are difficult to fabricate.
Innovation Solution
A lens design with a concave portion and upper surface that includes a flat or convex surface, allowing for increased alignment tolerance and easy fabrication, disperses light extensively through primary and secondary refraction, and features an elongated entrance region to distribute light uniformly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a lens with a disk-shaped light orientation pattern is applied, then light can be oriented in specific directions, but bright portions and dark portions are formed making uniform light distribution difficult
Solution Approach 1:
The lens is segmented into multiple functional regions: a first lens portion with a specific refractive index for primary light refraction, and a second lens portion with a different refractive index for secondary refraction. This segmentation allows independent optimization of each region's optical properties to achieve uniform light distribution while maintaining manufacturing feasibility.
Solution Approach 2:
Different regions of the lens are assigned different local optical properties. The first lens portion has a refractive index optimized for capturing light from the LED, while the second lens portion has a refractive index optimized for directing light in specific patterns. This local quality differentiation enables uniform light distribution without requiring perfect alignment.
2Manufacturing precision
If the alignment between LED and lens is made very precise, then light distribution can be controlled accurately, but manufacturing complexity and cost increase
Solution Approach 1:
The lens design incorporates an alignment tolerance compensation mechanism where the optical path is designed to be relatively insensitive to small misalignments. The specific refractive index configuration and lens geometry create a buffer that compensates for manufacturing variations, cushioning the impact of alignment errors before they affect light distribution.
3Ease of manufacture
If a conventional lens design is used, then fabrication is straightforward, but alignment errors cause non-uniform light distribution
Solution Approach 1:
The lens design changes key optical parameters - specifically the refractive indices of different lens portions - to achieve a balance between manufacturing ease and light distribution uniformity. By selecting specific refractive index values for the first and second lens portions, the design achieves tolerance to alignment errors while maintaining uniform light output.
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 lens design achieves uniform light distribution over large areas by minimizing alignment errors and simplifying fabrication, reducing bright and dark portions, and enhancing light orientation patterns.
Implementation Method 1
primary refraction occurs in a concave portion of a lens and secondary refraction occurs in an upper surface of the lens
Data Source
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Figure 4(a)~5(b)
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AI summary
Alight emitting module including a lens is provided. The light emitting module includes a light emitting diode chip, and a lens. The lens according to an embodiment includes a lower surface having a concave portion on which light emitted from the light emitting diode chip is incident, and an upper surface from which the light incident on the concave portion is emitted. The upper surface of the lens includes a concave surface positioned in a central axis thereof. The concave portion of the lower surface includes at least one of a surface perpendicular to the central axis and a downwardly convex surface. At least one of the surface perpendicular to the central axis and the downwardly convex surface is positioned in a region narrower than an entrance region of the concave portion. Furthermore, a lens according to another embodiment can implement an elongated light orientation pattern to emit uniform light over a large area.