Pixelated LED Chip Substrate Recess Layout for Low Cross-Talk
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Solution Overview
Problem
Conventional LED array devices face challenges in achieving small pixel pitches due to difficulties in preventing emission overlap and ensuring homogeneity, particularly with omnidirectional emissions and the need for light segregation structures that can reduce light utilization efficiency.
Innovation Solution
The use of pixelated-LED chips with protruding features of varying sizes, shapes, and distributions, along with underfill materials and lumiphoric materials, to align recesses between pixels and reduce cross-talk while maintaining light utilization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If light segregation structures are added to prevent emission overlap, then pixel resolution is improved, but light utilization efficiency deteriorates
Solution Approach 1:
The substrate surface is segmented into discrete pixel regions separated by recesses or trenches. This segmentation physically divides the light paths of adjacent pixels, preventing emission overlap and improving pixel resolution without requiring additional light blocking structures that would reduce overall light output.
Solution Approach 2:
The recesses or trenches are strategically positioned only at the boundaries between pixels where light segregation is needed, rather than throughout the entire device. This localized approach provides effective light separation at pixel interfaces while minimizing impact on the light extraction efficiency of the pixel active areas.
2Manufacturing precision
If pixel pitch is reduced to increase resolution, then display density is improved, but emission overlap between adjacent pixels worsens
Solution Approach 1:
By segmenting the substrate surface with recesses or trenches between pixels, the patent creates physical barriers that maintain light separation even when pixels are closely spaced. This allows for reduced pixel pitch and increased display resolution without suffering from emission overlap, as the recesses prevent light from one pixel from spilling into adjacent pixel regions.
3Ease of manufacture
If conventional pick-and-place techniques are used for mounting LED components, then manufacturing simplicity is maintained, but reliability in high-density arrays deteriorates
Solution Approach 1:
The patent merges multiple LED components onto a single substrate to form integrated pixel modules. This consolidation reduces the number of separate mounting operations required, simplifying the manufacturing process while improving reliability by reducing the total number of interconnections and mounting points in high-density arrays.
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 enhances contrast and inter-pixel illumination homogeneity, improving the manufacturability and performance of LED array devices by reducing emission overlap and maintaining efficient light usage.
Implementation Method 1
Each pixel comprises a different active layer portion and a different light-transmissive substrate portion, and each pixel emits different wavelengths of visible light
Data Source
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AI summary
Pixelated-LED chips and related methods are disclosed. A pixelated-LED chip includes an active layer with independently electrically accessible active layer portions arranged on or over a light-transmissive substrate. The active layer portions are configured to illuminate different light-transmissive substrate portions to form pixels. Various enhancements may beneficially provide increased contrast (i.e., reduced cross-talk between pixels) and/or promote inter-pixel illumination homogeneity, without unduly restricting light utilization efficiency. In some aspects, a light extraction surface of each substrate portion includes protruding features and light extraction surface recesses. Lateral borders between different pixels are aligned with selected light extraction surface recesses. In some aspects, selected light extraction surface recesses extend through an entire thickness of the substrate. Other technical benefits may additionally or alternatively be achieved.