Transparent Display Substrate Layout for High-PPI Light Transmittance
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Solution Overview
Problem
Current large-size transparent display devices face challenges in increasing pixel density (PPI) due to the limitations of metal wiring density and the need for auxiliary cathodes, which reduce the transparent region area and cause light transmittance issues, leading to ghost phenomena in user experience.
Innovation Solution
A display substrate design incorporating a light-shielding layer multiplexed as an auxiliary electrode, connected with the second electrode, to reduce resistance drop and increase the transparent region area, while maintaining high pixel density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If metal wiring density is increased to achieve higher pixel density, then pixel density (PPI) is improved, but the transparent region area is reduced and light transmittance deteriorates
Solution Approach 1:
The patent combines the light-shielding layer and auxiliary electrode into a single integrated structure. The light-shielding layer serves dual functions: blocking light to prevent ghost phenomena and acting as an auxiliary electrode to reduce resistance drop, thereby eliminating the need for separate auxiliary cathodes that would occupy transparent region space.
Solution Approach 2:
The light-shielding layer is designed to perform multiple functions simultaneously: light shielding to prevent ghosting effects and electrical conduction as an auxiliary electrode. This multi-functionality allows the structure to address both light transmittance issues and electrical resistance issues without requiring additional components that would reduce the transparent region area.
2Reliability
If auxiliary cathodes are added to reduce resistance drop, then electrical performance is improved, but the transparent region area is reduced
Solution Approach 1:
The auxiliary electrode function is merged with the light-shielding layer, eliminating the need for separate auxiliary cathodes. The light-shielding layer is electrically connected to the second electrode and serves as the auxiliary electrode, providing the necessary electrical performance improvement without occupying additional transparent region space.
Solution Approach 2:
The light-shielding layer is designed to perform both light shielding and electrical conduction functions. By making the light-shielding layer electrically conductive and connecting it to the second electrode, it serves dual purposes: preventing ghost phenomena through light blocking and reducing resistance drop through its auxiliary electrode function.
3Illumination intensity
If transparent region area is increased to improve light transmittance, then light transmittance is improved, but pixel density is reduced
Solution Approach 1:
The integration of light-shielding and auxiliary electrode functions into a single layer allows for more efficient space utilization. The overlapping projection design enables the light-shielding layer to cover the sub-pixel driving circuit area effectively, maximizing light transmittance in the transparent region while maintaining high pixel density through compact arrangement.
Solution Approach 2:
The patent utilizes the vertical dimension by creating overlapping projections in the orthographic view. The light-shielding layer is positioned to overlap with the sub-pixel driving circuit in the vertical dimension, allowing horizontal space to be used more efficiently for both transparent regions and pixel elements, thereby maintaining high pixel density while improving light transmittance.
Data Source
AI summary
A display substrate and a display device are provided. The display substrate includes a base substrate and a light-shielding layer. The base substrate includes a display region including repeating units, each repeating unit includes a transparent region and a pixel region, the pixel region includes sub-pixels, each sub-pixel includes a sub-pixel driving circuit and a light-emitting element, and the light-emitting element includes a first electrode, a second electrode, and a light-emitting layer located between the first electrode and the second electrode. The light-shielding layer is located on a side of the sub-pixel driving circuit close to the base substrate, at least part of an orthographic projection of the light-shielding layer on a main surface of the base substrate overlaps with an orthographic projection of the sub-pixel driving circuit on the main surface of the base substrate, and the light-shielding layer is connected with the second electrode.