Vertically Stacked Microdisplay Sub-Pixels for Compact Pixel Area
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Solution Overview
Problem
Conventional microdisplay pixel formation techniques require multiple transfer processes, result in increased pixel size due to the need for thick black matrices to prevent light interference, and are challenging for defect repair, leading to difficulties in achieving high resolution and efficient manufacturing.
Innovation Solution
A microdisplay pixel structure with vertically stacked sub-pixels, where each sub-pixel is separated by current blocking layers to prevent leakage currents and allow independent current flow, reducing the overall pixel area and simplifying the transfer and repair processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If three coplanar sub-pixels are used to form one pixel, then full color can be realized, but the transfer process becomes complex requiring three separate transfers
Solution Approach 1:
The patent transitions from a planar arrangement of sub-pixels to a three-dimensional vertical stacking configuration. Multiple sub-pixels are stacked in the thickness direction of the substrate, allowing all sub-pixels to be transferred in a single process while maintaining full color capability. This dimensional change resolves the contradiction by enabling color completeness without requiring multiple sequential transfers.
2Reliability
If a thick black matrix is used to prevent light interference between sub-pixels, then color accuracy improves, but pixel area increases reducing resolution
Solution Approach 1:
The patent eliminates the need for thick black matrices by stacking sub-pixels vertically. The current blocking layers are positioned between stacked sub-pixels in the thickness direction, preventing lateral light interference without consuming horizontal pixel area. This allows high resolution to be maintained while ensuring color accuracy through effective light isolation.
Solution Approach 2:
The patent implements localized current blocking functionality at specific interfaces between sub-pixels using thin current blocking layers. Instead of using a thick black matrix across the entire pixel area, current blocking is applied locally only where needed between stacked sub-pixels, maintaining color accuracy while minimizing impact on pixel area and resolution.
3Ease of manufacture
If conventional pixel formation technique is used, then manufacturing process is established, but defect repair becomes difficult
Solution Approach 1:
The patent segments the pixel into vertically stacked sub-pixels with current blocking layers between them. This segmentation allows individual sub-pixels to be independently replaced if defective. The modular structure enables repair by removing only the defective sub-pixel and current blocking layer, then adding a new sub-pixel, without requiring replacement of the entire pixel or complex reconfiguration.
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 reduces the pixel area, simplifies the transfer process to one step, and facilitates easier defect repair by allowing individual sub-pixel replacement, enhancing manufacturing efficiency and resolution.
Implementation Method 1
a first current blocking layer formed on the first sub-pixel and configured to block a leakage current directed toward the first sub-pixel or introduced from the first sub-pixel
Data Source
AI summary
Disclosed is a unit pixel of a microdisplay. In the unit pixel, sub-pixels which respectively form blue, green, and red light are vertically stacked on a growth substrate. Accordingly, the overall area of the unit pixel is reduced, and a transfer process is easily performed.