Layered Phosphor Conversion Structure for LED Color Consistency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor components emitting mixed-colored radiation face issues with color variation over an angle range, which is currently addressed by using a diffuser that reduces brightness.
Innovation Solution
An optoelectronic semiconductor component with a conversion element arranged on the radiation exit surface, featuring a stack of conversion layers with decreasing lateral extent, providing a higher conversion degree at the center than at edges, and a reflective element to direct radiation towards the main axis, ensuring consistent color and brightness across a wide angle range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a diffuser is used on top of the conversion element to deflect light and encourage mixture, then color consistency is improved, but brightness is reduced
Solution Approach 1:
The conversion element is divided into multiple conversion layers with different lateral extents, where each layer converts a portion of the primary radiation to secondary radiation. This segmentation allows for controlled wavelength conversion without requiring a diffuser, thereby maintaining brightness while achieving color consistency.
Solution Approach 2:
Different regions of the conversion element have different properties - the conversion layers have decreasing lateral extents from the center outward, creating local variations in conversion efficiency. This local quality variation ensures that light rays at different angles experience appropriate conversion, achieving color consistency without the brightness loss associated with diffusers.
2Ease of manufacture
If the conversion element has uniform lateral extent across all layers, then manufacturing is simplified, but color variation over angle range increases
Solution Approach 1:
The conversion layers are designed with asymmetric lateral extents, where each successive layer has a smaller lateral extent than the previous one. This asymmetric design creates a gradient structure that optimizes the conversion of light rays at different angles, significantly reducing color variation over the emission angle range while remaining manufacturable.
Solution Approach 2:
The solution transitions from a two-dimensional uniform conversion layer to a three-dimensional stacked structure with varying lateral extents. This dimensional change allows for angular-dependent optimization of light conversion, where the vertical stacking with decreasing lateral extents creates a gradient that addresses color consistency across different emission angles.
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 improved color consistency and reduced brightness loss compared to components using diffusers, with an 80% reduction in color-over-angle variation and only 1.4% brightness loss, while maintaining better radiation distribution and conversion efficiency.
Implementation Method 1
a conversion element provided for wavelength conversion of at least part of the primary radiation into secondary radiation
Implementation Method 2
a reflective element to direct radiation towards the main axis
Data Source
AI summary
In an embodiment an optoelectronic semiconductor component includes an optoelectronic semiconductor chip having a radiation exit surface and side surfaces running transversely with respect to the radiation exit surface, the optoelectronic semiconductor chip configured to emit primary radiation through the radiation exit surface, a conversion element arranged on the radiation exit surface, the conversion element configured to convert at least part of the primary radiation into secondary radiation and including a stack of at least two conversion layers and a reflective element laterally surrounding the optoelectronic semiconductor chip, wherein a lateral extent of the conversion layers decreases from a layer which is closest to the radiation exit surface to a layer which is most distant from the radiation exit surface, wherein the conversion element includes a part laterally extending beyond the radiation exit surface and being concavely curved, wherein the conversion element is partly arranged on the reflective element, and wherein the conversion element is arranged on a concavely curved surface of the reflective element.