Micro LED Display Substrate Transfer for High-PPI Chip Spacing
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Solution Overview
Problem
Current Micro LED display substrates face challenges in resolution and display effect due to the spacing of light emitting chips on sapphire substrates, which limits their performance compared to Organic Light Emitting Diode (OLED) displays.
Innovation Solution
A method is developed to prepare a display substrate by forming a light emitting chip layer on a first substrate, transferring it to a second substrate with a drive circuit layer, and applying an optical film layer to scatter and convert light, thereby reducing chip spacing and enhancing resolution and display effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If light emitting chips are arranged on sapphire substrates, then the substrate structure is simple and easy to manufacture, but the chip spacing is large which limits resolution and display effect
Solution Approach 1:
The patent divides the manufacturing process into two independent stages: first growing LED chips on sapphire substrates, then transferring them to a separate drive circuit substrate. This segmentation allows optimization of chip growth conditions while achieving dense packing on the final substrate without the constraints of the sapphire substrate structure.
Solution Approach 2:
The patent introduces a transfer substrate as an intermediary component between the sapphire substrate and the drive circuit substrate. This transfer substrate facilitates the movement of LED chips from the growth substrate to the final display substrate, enabling close spacing while maintaining manufacturing feasibility.
2Manufacturing precision
If light emitting chips are spaced further apart, then the manufacturing process is simpler, but the resolution and PPI (pixels per inch) are reduced
Solution Approach 1:
The patent transitions from two-dimensional chip arrangement on a single substrate to a three-dimensional process involving multiple substrates stacked and transferred. This dimensional change enables achieving high density (high PPI) by utilizing the transfer process to pack chips more closely than would be possible on a single flat substrate.
3Manufacturing precision
If more light emitting chips are packed closer together, then the resolution and display effect improve, but the manufacturing complexity increases
Solution Approach 1:
The patent performs preliminary actions by pre-growing LED chips on sapphire substrates with optimized spacing, then transferring them en masse to the drive circuit substrate. This preliminary preparation simplifies the overall manufacturing complexity by decoupling the chip growth process from the final packaging process, allowing high-density packing without proportionally increasing manufacturing difficulty.
4Device complexity
If a single substrate is used for both LED chips and drive circuits, then the device structure is simpler, but the chip spacing cannot be minimized
Solution Approach 1:
The patent segments the device into separate functional modules: LED chip growth on sapphire substrate, drive circuit fabrication on separate substrate, and final assembly through transfer. This segmentation enables each module to be optimized independently, achieving minimal chip spacing in the final assembly while keeping individual substrate structures relatively simple.
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 method improves the display substrate's resolution and visual performance by allowing for closer packing of light emitting chips and the use of optical film layers to convert and scatter light, achieving a high PPI design and improved product yield.
Implementation Method 1
the optical film layer is configured to scatter the light of the first color
Implementation Method 2
convert the light of the first color into light of a second color
Implementation Method 3
convert the light of the first color into light of a third color
Data Source
AI summary
A method for preparing the display substrate includes: providing a first substrate, and forming a light emitting chip layer on the first substrate to form a first backplane, wherein the light emitting chip layer includes: light emitting chips arranged in array, which are configured to emit light of a first color and include N sub-pixels, and N is a positive integer greater than or equal to 1; providing a second substrate, and forming a drive circuit layer on the second substrate to form a second backplane, wherein the drive circuit layer includes: connection electrodes arranged in an array, and the light emitting chips correspond to the connection electrodes one-by-one; transferring the first backplane from which the first substrate is peeled off to the second backplane; forming an optical film layer on a side of the light emitting chip layer away from the second backplane.