Transparent Display Substrate Capacitor Stacking
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Solution Overview
Problem
Existing transparent display devices face challenges in achieving high transparency while maintaining sufficient pixel capacitance, leading to display mura issues due to the reduced area occupied by storage capacitors in the light-emitting region.
Innovation Solution
A transparent display substrate design where the self-luminescent device is positioned on a side of the capacitor away from the thin film transistor, allowing the capacitor to occupy a larger area within the light-emitting region, ensuring adequate pixel capacitance without compromising transparency by using a capacitor configuration with a light-nontransmitting first electrode and a light-transmitting second electrode, and integrating a planarization layer to minimize film thickness in the transparent region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the storage capacitor area is reduced to increase transparent region area, then transparency is improved, but pixel capacitance becomes insufficient causing display mura
Solution Approach 1:
The patent utilizes the vertical dimension by stacking the self-luminescent device above the capacitor in the light-emitting region. This three-dimensional arrangement allows the capacitor to occupy the same planar area as the light-emitting device would, effectively doubling the capacitor area without reducing the transparent region area, thus resolving the contradiction between transparency and pixel capacitance
Solution Approach 2:
The first electrode of the capacitor serves dual functions: as a capacitor electrode for storing charge and as a reflective electrode for the self-luminescent device. This multi-functionality allows the capacitor structure to contribute to both pixel capacitance and light reflection, eliminating the need for separate reflective electrode structures and maximizing the use of available space
2Reliability
If the capacitor occupies larger area in light-emitting region, then pixel capacitance is sufficient, but transparency is compromised
Solution Approach 1:
By moving the capacitor configuration into the vertical dimension with the self-luminescent device stacked above it, the patent allows the capacitor to effectively occupy the light-emitting region area without physically blocking light in the transparent region. The capacitor's first electrode is positioned at the bottom while the light-emitting device sits above, creating a vertical arrangement that maximizes capacitance area while preserving transparency
Solution Approach 2:
The patent applies different optical properties to different regions: the first electrode is designed as a light-nontransmitting reflective electrode in the light-emitting region to maximize light reflection efficiency, while the overall capacitor structure is arranged to minimize impact on the transparent region's light transmission, thus optimizing local optical quality for each functional requirement
Data Source
AI summary
A transparent display substrate includes a first base and a plurality of sub-pixels disposed on the first base. At least one sub-pixel of the plurality of sub-pixels has a light-emitting region and a transparent region. In the at least one sub-pixel, each sub-pixel includes at least one thin-film transistor, a capacitor and a self-luminescent device that are located in the light-emitting region of the sub-pixel. The self-luminescent device is disposed on a side of the capacitor away from the at least one thin film transistor in a direction perpendicular to the first base. The at least one thin film transistor and the capacitor are electrically connected.