Pixelated Wavelength-Conversion Layer With Sidewall Light Barriers
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Solution Overview
Problem
The challenge lies in creating reliable thin inter-pixel light barriers with high aspect ratios in pixelated wavelength-conversion layers, particularly in RGB pixel arrangements, where maintaining adequate contrast ratio between adjacent pixels is difficult due to the narrow width and high aspect ratio of trenches, and forming light barriers within these trenches is problematic.
Innovation Solution
A method involving the formation of a wavelength-conversion layer with regions of three distinct materials, where sidewall layers are deposited between adjacent regions to reduce light transmission, using a process that includes masking and depositing different conversion layer materials on a substrate, followed by selective removal of mask materials and deposition of sidewall layers to achieve thin inter-pixel barriers with large aspect ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If trenches are made narrow to achieve high pixel density, then pixel density is improved, but the ability to form reliable light barriers deteriorates
Solution Approach 1:
The patent transitions from attempting to form light barriers within the narrow trench space (horizontal dimension) to depositing sidewall layers on the vertical side surfaces of the trenches. This vertical dimension approach allows light barrier material to be applied where space is available, rather than trying to fit material into the constrained horizontal trench space.
Solution Approach 2:
The patent introduces sidewall layers as an intermediary structure formed on the trench surfaces before filling the trench with light barrier material. These sidewall layers serve as intermediate structures that facilitate the subsequent formation of reliable light barriers by providing nucleation sites and structural support within the narrow trench geometry.
2Manufacturing precision
If trenches are made deep to achieve high aspect ratio barriers, then contrast ratio is improved, but manufacturing complexity increases
Solution Approach 1:
The patent performs preliminary actions by forming sidewall layers on the trench surfaces before filling the trenches with light barrier material. This preliminary sidewall formation simplifies the subsequent trench filling process by providing a prepared surface that facilitates uniform material deposition and reduces manufacturing complexity compared to direct trench filling.
Solution Approach 2:
The light barrier formation process is segmented into multiple steps: first forming sidewall layers on the trench surfaces, then filling the trenches with light barrier material. This segmentation of the manufacturing process allows each step to be optimized independently, reducing overall manufacturing complexity while achieving the desired deep, high aspect ratio barriers.
3Object-generated harmful factors
If sidewall layers are used to form light barriers, then light crosstalk is reduced, but device complexity increases
Solution Approach 1:
Sidewall layers serve as intermediary light barrier structures that effectively reduce light crosstalk between adjacent pixels. By positioning these layers on the vertical sidewalls of the trenches, the patent creates effective optical isolation without requiring complex three-dimensional structures, thus reducing light crosstalk while maintaining relatively simple device geometry.
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 wavelength-conversion layers with high aspect ratio inter-pixel barriers, reducing light crosstalk and enhancing contrast ratio between adjacent pixels, allowing for more precise control over light distribution in microLED arrays.
Implementation Method 1
the sidewall layers arranged so as to reduce transmission of light between adjacent regions of the conversion layer materials
Implementation Method 2
At least two among the first, second, and third conversion layer materials are wavelength-converting phosphor materials
Data Source
AI summary
A first conversion layer material is formed on unmasked pixel areas of a substrate. Mask material is selectively removed from a second set of pixel areas, leaving a third set of pixel areas masked. A coating is formed on sidewalls of the second pixel areas, and then a second conversion layer material is formed on the second pixel areas and against their sidewalls. Mask material is removed from the third pixel areas, a coating is formed on sidewalls of the third pixel areas, and a third conversion layer material is formed on the third pixel areas and against their sidewalls. The resulting wavelength-conversion layer includes contiguously arranged regions of the first, second, and third conversion layer materials, at least two of which are wavelength-converting phosphor materials. The sidewall coatings between the regions act as barriers to lateral light transmission.