Lateral Pixel Structure for Micro-LED Displays
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Solution Overview
Problem
Micro-LED display technology faces challenges in manufacturing cost, energy efficiency, and heat dissipation due to the need for multiple LED emitters and stacked wavelength conversion units, which also complicates integration of optical elements and reduces device lifetime.
Innovation Solution
A pixel structure with LED emitters and wavelength conversion units arranged adjacent to each other on a substrate, allowing for reduced height, improved heat dissipation, and reduced risk of radiation leakage, while using only one type of LED emitter for simpler manufacturing and achieving higher efficiency by directing converted radiation perpendicular to the emission plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If wavelength conversion units are stacked on top of LED emitters to absorb blue radiation, then absorption efficiency is improved, but heat dissipation deteriorates and device lifetime is reduced
Solution Approach 1:
The patent transitions from a vertical stacking arrangement (3D height direction) to a lateral adjacent arrangement (2D plane direction) of wavelength conversion units relative to LED emitters. This dimensional change allows the conversion units to be positioned beside the emitters rather than above them, fundamentally altering the spatial relationship to resolve the heat dissipation issue while maintaining absorption efficiency through extended lateral absorption paths.
Solution Approach 2:
The patent divides the wavelength conversion function across multiple conversion units positioned laterally adjacent to different LED emitters, rather than concentrating all conversion function in stacked units above a single emitter. This segmentation distributes the heat generation spatially, allowing better thermal management while maintaining overall conversion efficiency.
2Loss of energy
If conversion units are made 100 μm thick to absorb most blue radiation, then absorption efficiency is improved, but manufacturing complexity increases due to large aspect ratio
Solution Approach 1:
The patent extends the absorption path from the vertical dimension (thickness direction) to the lateral dimension (plane direction). Instead of increasing conversion unit thickness to 100 μm, the units are positioned laterally adjacent to emitters, allowing the absorption path to extend through the lateral distance between emitter and conversion unit boundaries, achieving sufficient absorption without excessive thickness.
Solution Approach 2:
The patent changes the geometric parameters of the conversion units, specifically reducing their thickness from 100 μm to 3 μm or less, while compensating for the reduced thickness by increasing the lateral absorption path length. This parameter transformation makes the structure manufacturable using standard micro structuring methods while maintaining absorption efficiency.
3Illumination intensity
If multiple types of LED emitters (red, green, blue) are used for direct emission, then color quality is improved, but manufacturing cost increases
Solution Approach 1:
The patent makes a single type of blue LED emitter perform multiple functions: directly emitting blue light and serving as a pump source for wavelength conversion units that generate green and red light. This universal use of blue emitters eliminates the need to manufacture and assemble three different emitter types, significantly reducing manufacturing complexity and cost while maintaining full RGB color capability.
Solution Approach 2:
The patent introduces wavelength conversion units as intermediary elements that convert blue radiation from the emitters into green and red radiation. These conversion units act as mediators that enable a single blue emitter type to produce all three primary colors, replacing the need for direct emission from three different emitter types and thereby simplifying the manufacturing process.
4Loss of energy
If stacked structures are used for wavelength conversion, then radiation conversion is achieved, but integration of optical elements becomes difficult
Solution Approach 1:
The patent repositions wavelength conversion units from a vertical stack above emitters to a lateral arrangement adjacent to emitters in the same plane. This dimensional change creates available vertical space above the emitter-conversion unit arrangement, allowing optical elements such as lenses to be integrated above the structure without interfering with the conversion function, thereby facilitating optical element integration.
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 configuration results in a more efficient, cost-effective, and longer-lasting micro-LED display with improved heat dissipation and reduced manufacturing complexity, enabling the production of RGB pixel structures with enhanced radiation conversion and placement flexibility.
Implementation Method 1
at least one wavelength conversion unit arranged on the substrate adjacent the LED emitter, the wavelength conversion unit being configured to convert the emission radiation to converted radiation
Implementation Method 2
The LED emitter chips are typically based on the GaN (gallium nitride) material system. Blue-to-red and blue-to-green radiation conversion units are stacked on top of corresponding LED pixels
Implementation Method 3
The blue spectral range radiation is partially absorbed by the conversion unit, the absorption following an exponential decrease to first order
Data Source
AI summary
A pixel structure for an electronic display, the pixel structure comprising a substrate, at least one LED emitter arranged on the substrate, and at least one wavelength conversion unit arranged on the substrate adjacent to the LED emitter. The LED emitter is configured to emit emission radiation, the emission radiation being within an emission wavelength range and emitted in one or multiple emission directions within a main emission plane. The wavelength conversion unit is configured to convert the emission radiation to converted radiation within a converted wavelength range, the converted wavelength range being different from the emission wavelength range. The converted radiation propagates from the wavelength conversion unit in a main conversion direction perpendicular to the main emission plane, the main conversion direction being, for example, a direction towards a user of an electronic device having an electronic display comprising at least one such pixel structure.