Partially-Reflective Layer for Inhomogeneous Light Beam Control
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Solution Overview
Problem
Existing semiconductor light sources, such as LEDs and OLEDs, struggle to produce light beams with suitable shape and luminance variation, as current methods fail to achieve the desired inhomogeneous output required for applications like automotive lighting and projection systems.
Innovation Solution
A semiconductor light source is enhanced with a partially-reflective layer of varying thickness and/or reflectivity, which alters the light transmittance characteristic laterally, allowing for controlled luminance variation across the output beam by reflecting more light back towards the optical enhancement section in thicker or high-reflectivity areas and transmitting more light in thinner or low-reflectivity areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a semiconductor light source is used to generate bright light with small etendue, then energy efficiency and compact size are improved, but the ability to produce inhomogeneous light beams with suitable shape and luminance variation deteriorates
Solution Approach 1:
The patent applies local quality by introducing a partially-reflective layer with spatially varying reflectivity across the light output surface. Different regions of the layer have different optical properties (varying reflectivity and transmittance), enabling localized control of light intensity and distribution. This allows the semiconductor light source to produce inhomogeneous light beams with tailored luminance patterns while maintaining the inherent energy efficiency of the LED structure.
2Shape
If multiple images or light beams are superimposed to achieve inhomogeneous luminance, then light beam shape control is improved, but device complexity increases
Solution Approach 1:
The patent extracts the light beam shaping function from the complex multi-beam superposition approach and integrates it directly into the light output surface through a partially-reflective layer. This single integrated component performs both light extraction and spatial intensity modulation, eliminating the need for separate optical elements to create multiple images or beams. The result is simplified device architecture while maintaining the ability to produce inhomogeneous light patterns.
3Ease of manufacture
If a uniform light output surface is used, then manufacturing simplicity is improved, but the ability to control luminance variation across the beam deteriorates
Solution Approach 1:
The patent applies parameter changes by varying the optical properties (reflectivity and transmittance) of the partially-reflective layer across different spatial locations. The layer's optical parameters are deliberately non-uniform, with regions having different reflectivity values to create the desired luminance distribution. This can be achieved through controlled variations in layer thickness, material composition, or structural features during manufacturing, enabling luminance control while maintaining compatibility with standard fabrication processes.
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 the creation of inhomogeneous light beams with varying luminance, suitable for applications like automotive lighting and projection systems, by indirectly proportional luminance adjustment based on the thickness and reflectivity of the partially-reflective layer, enhancing the light source's efficiency and adaptability.
Implementation Method 1
a partially-reflective layer covering at least a portion of the top of the optical enhancement section and adapted to reflect a portion of the output light towards the optical enhancement section
Data Source
AI summary
There is proposed a light source comprising: a semiconductor diode structure adapted to generate light; and an optical enhancement section above the semiconductor diode structure and adapted to output light from the semiconductor diode structure. A partially-reflective layer covers at least a portion of the top of the optical enhancement section and is adapted to reflect a portion of the output light towards the optical enhancement section. The partially-reflective layer has a light transmittance characteristic that varies laterally.