Inkjet Printing System for Under-Screen Camera
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Solution Overview
Problem
Current inkjet printing systems for OLEDs face challenges such as color mixing, inability to achieve fine film thickness adjustment, and low nozzle utilization rate, particularly in under-screen camera technology with side-by-side pixel architecture.
Innovation Solution
The inkjet printing system employs a pixel opening structure with a line bank (LB) architecture, featuring first and second pixel openings with different areas and ink droplet flow rates controlled by an ink droplet flow rate device, allowing for improved nozzle utilization and reduced risk of color mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the pixel opening area is reduced to allow more light into the camera module, then the camera imaging capability is improved, but the film thickness uniformity deteriorates and color mixing risk increases
Solution Approach 1:
The pixel opening is segmented into two distinct regions: a first pixel opening for display and a second pixel opening for under-screen camera. This segmentation allows each region to have optimized dimensions and ink droplet quantities, enabling the camera region to receive sufficient light while the display region maintains proper film thickness. The segmentation resolves the contradiction by allowing different functional requirements to be met in different spatial zones within the same pixel structure.
Solution Approach 2:
Different ink droplet quantities are applied to different pixel opening regions. The first pixel opening receives a first quantity of ink droplets while the second pixel opening receives a second quantity, creating local quality variations. This allows the camera region to have optimized light transmission properties while the display region maintains appropriate film thickness, resolving the contradiction between light transmission and film thickness uniformity through spatially differentiated material properties.
2Illumination intensity
If the pixel opening area is reduced for under-screen camera technology, then the camera module can capture more light, but the nozzle utilization rate decreases
Solution Approach 1:
The pixel opening is divided into first and second pixel openings with different areas and ink droplet quantities. This segmentation enables the smaller second pixel opening (for camera) to be compensated by the larger first pixel opening (for display), allowing all nozzles to remain usable while maintaining proper film thickness. The segmentation resolves the contradiction by distributing ink droplet delivery across different regions, ensuring full nozzle utilization despite the reduced camera opening area.
3Illumination intensity
If the pixel opening area is reduced to achieve under-screen camera function, then the camera imaging is improved, but the droplet placement accuracy requirement increases
Solution Approach 1:
The pixel opening is segmented into first and second pixel openings, allowing independent optimization of ink droplet quantities for each region. The first pixel opening receives a first quantity of ink droplets while the second pixel opening receives a second quantity, enabling the system to meet camera light transmission requirements without imposing stringent droplet placement accuracy requirements. The segmentation resolves the contradiction by distributing the precision requirements across different regions with different functional demands.
4Illumination intensity
If the pixel opening area is reduced for under-screen camera technology, then the camera module can function effectively, but color mixing risk increases
Solution Approach 1:
The pixel opening is divided into first and second pixel openings with different ink droplet quantities. This segmentation creates distinct ink deposition zones that prevent color mixing between adjacent pixels. The first pixel opening receives a first quantity of ink droplets while the second pixel opening receives a second quantity, ensuring that each region maintains proper ink coverage without encroaching on adjacent color regions. The segmentation resolves the contradiction by establishing spatial boundaries that prevent color mixing while allowing the camera region to receive sufficient light.
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 enables effective nozzle utilization and fine film thickness adjustment, reducing the risk of color mixing and meeting transmittance requirements for under-screen imaging without stringent requirements on ink droplet placement accuracy.
Implementation Method 1
An inkjet printing (IJP) OLED is a new preparation process for OLED, compared with a traditional evaporation process, the inkjet printing OLED carries out printing according to needs of organic materials
Data Source
AI summary
An inkjet printing system is disclosed in the present disclosure. The inkjet printing system includes: an inkjet printing device with nozzles having pixel ink, a display substrate including a display region and an under-screen camera region, and an ink droplet flow rate control device connected to the nozzles. The nozzles are arranged above the display substrate. The display substrate includes a base, and a pixel defining layer on a surface of the base. The pixel defining layer is disposed with first pixel openings in the display region, and second pixel openings in the under-screen camera region. The first pixel opening has a greater opening area than the second pixel opening. The ink droplet flow rate control device is used to respectively control ink droplet outflow rates of pixel ink of the nozzles corresponding to the display region and the under-screen camera region.