Low Profile Lighting Module Uniform Luminance via Diffuser
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Solution Overview
Problem
Conventional LED lighting modules often suffer from non-uniform luminance distribution and high optical loss due to the physical arrangement of multiple LED sources, which results in hotspots and poor color uniformity, especially when attempting to produce white light for everyday applications.
Innovation Solution
The use of primary optics, such as custom cylindrical or frustoconical shapes, and secondary optics like diffusers with non-uniform optical characteristics, along with reflective surfaces, to control and redirect light emissions, achieving a more uniform luminance distribution and reduced optical loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple LED packages are mounted close together to increase luminous output, then the lighting efficiency improves, but hotspots are created and luminance uniformity deteriorates
Solution Approach 1:
A diffuser element is introduced as an intermediary component between the LED packages and the external environment. This diffuser scatters the light from multiple LED packages, eliminating hotspots and achieving uniform luminance distribution across the entire emission surface while preserving the high luminous output from the closely spaced LEDs.
Solution Approach 2:
The diffuser element is designed with spatially varying optical characteristics, where different regions of the diffuser have different scattering properties. This allows local optimization of light distribution to compensate for the non-uniform emission pattern of closely spaced LED packages, achieving overall uniformity while maintaining high luminous output.
2Manufacturing precision
If a diffuser element is added to improve luminance uniformity, then hotspot reduction improves, but optical loss increases
Solution Approach 1:
The diffuser element is designed with optimized optical parameters including specific scattering coefficients, refractive indices, and thickness values that balance uniformity improvement with optical loss minimization. By carefully controlling these parameters, the diffuser achieves effective hotspot reduction while maintaining high optical efficiency.
3Ease of manufacture
If the distance between LED packages is reduced to increase packing density, then manufacturing cost decreases, but luminance uniformity deteriorates
Solution Approach 1:
The diffuser element acts as a mediating component that allows LED packages to be mounted at closer spacing while still achieving acceptable luminance uniformity. The diffuser's scattering properties compensate for the reduced distance between packages, enabling higher packing density without proportionally worsening uniformity.
4Device complexity
If conventional LED packages are used without optical modification, then device complexity is minimized, but color uniformity and luminance distribution are non-uniform
Solution Approach 1:
The diffuser element is integrated directly with the LED package structure, merging the optical functions of light extraction, directionality, and uniformity improvement into a single combined component. This integration achieves color and luminance uniformity without adding separate complex optical systems.
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
This approach enables a significantly more uniform light emission with minimal loss, achieving an optical efficiency of >80% and a variance in output irradiance/illuminance of <25%, while maintaining a minimized cross-sectional profile, thus improving the overall efficiency and appearance of LED-based lighting modules.
Implementation Method 1
Light emitting diodes (LEDs) are solid state devices that convert electric energy to light and generally comprise one or more active regions of semiconductor material interposed between oppositely doped semiconductor layers. When a bias is applied across the doped layers, holes and electrons are injected into the active region where they recombine to generate light.
Implementation Method 2
The surrounding phosphor material 'downconverts' some of the blue light, changing it to yellow light. Some of the blue light passes through the phosphor without being changed while a substantial portion of the light is downconverted to yellow.
Implementation Method 3
One known approach to the problem of color mixing is to use a diffuser to scatter light from the various sources.
Data Source
AI summary
A low profile lighting module. Devices according to this disclosure can produce a uniform light intensity output profile, limiting the perceived appearance of individual point sources, from direct lighting modules comprising several light emitting diodes. Individual lighting device components are disclosed that can contribute to this uniform profile, including: primary optics, secondary optics, and contoured housing elements. These components can interact with and control emitted light, thus adjusting its pattern. These components can alter the direction of emitted light, providing a more uniform light intensity over a wider range of viewing angle.