Uniform Illumination Lighting Module with Parabolic Focus
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Solution Overview
Problem
Lighting modules often suffer from non-uniform luminous intensity, leading to undesirable light spots that interfere with applications like fluorescence photography, despite attempts to address this issue through light diffusers and edge-type backlight modules.
Innovation Solution
A uniform illumination lighting module is designed with a first optical medium, a lower reflective surface, and a concave reflective surface, where the light source is positioned at the parabolic focus of the concave reflective surface, ensuring uniform luminous intensity across the transmittance area by using a combination of specular and diffuse reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If light sources are spaced further apart in direct-type backlight modules, then device complexity is reduced, but luminous intensity uniformity deteriorates causing light spots
Solution Approach 1:
The patent inverts the conventional direct-type backlight structure by using edge-type backlighting where light sources are positioned at the edges rather than at the back center. This inversion allows light to enter the optical medium from the sides and propagate through total internal reflection, achieving uniform illumination without requiring multiple spaced light sources across the back plane.
Solution Approach 2:
The patent transitions from a two-dimensional array of light sources in the back plane to a one-dimensional edge placement configuration. By moving light sources to the edges and utilizing the third dimension (depth/thickness of the optical medium) for light propagation via total internal reflection, the system achieves uniform illumination with fewer light sources.
2Illumination intensity
If light diffusers are added to direct-type backlight modules, then luminous intensity uniformity improves, but device complexity increases
Solution Approach 1:
The optical medium itself serves the dual function of guiding light and providing uniform illumination without requiring separate diffuser components. The total internal reflection within the optical medium automatically distributes light uniformly across the exit surface, making the system self-sufficient and eliminating the need for additional optical components.
3Illumination intensity
If multiple light sources are used in edge-type backlight modules, then luminous intensity uniformity improves, but light concentration at edges increases
Solution Approach 1:
The patent applies different optical properties to different regions of the optical medium. The optical medium is designed with specific refractive index variations or surface characteristics at the edges versus the center, allowing light to be properly distributed and preventing concentration at edge regions while maintaining overall uniformity.
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 effectively eliminates light spots by distributing light uniformly across the transmittance area, enhancing the consistency of illumination and reducing the appearance of hot spots, particularly at the edges, thereby improving the quality of light sources in sensitive applications.
Implementation Method 1
a concave reflective surface (20, 21) configured to reflect light emitted from the light source (24) to produce light of uniform luminous intensity upon a lower reflective surface (18)
Implementation Method 2
a lower reflective surface (18) which is configured to perform diffuse reflection
Data Source
AI summary
A uniform illumination lighting module is disclosed herein. In some embodiments, the uniform illumination lighting module comprises a first optical medium, a lower reflective surface disposed adjacent to a bottom boundary of the first optical medium, a concave reflective surface disposed adjacent to a side boundary of the first optical medium, and a light source, wherein at least a portion of the first optical medium is disposed between the light source and the concave reflective surface. In some embodiments, the uniform illumination lighting module further comprises a second optical medium disposed adjacent to a top boundary of the first optical medium. In preferred embodiments, the concave reflective surface is substantially parabolic and the light source is disposed at a parabolic focus of the concave reflective surface.