Transparent OLED Substrate with Variable Protective Layer Thickness
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Solution Overview
Problem
Existing organic electroluminescent display devices face challenges in achieving high transparency due to light loss caused by organic and inorganic protective layers in non-light-emitting regions, leading to a poor transparent display effect and potential cathode breakdown.
Innovation Solution
An organic electroluminescent display substrate with a base substrate and pixel units featuring a light-emitting region and a non-light-emitting region, where a transparent material layer is introduced between the second electrode layer and the base substrate, made of metallic oxide materials like ITO or IZO, to reduce light loss and maintain cathode integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If organic and inorganic protective layers are removed in non-light-emitting regions to increase transparency, then light transmittance is improved, but a large gradient is generated at the interface between light-emitting and non-light-emitting regions causing cathode breakdown
Solution Approach 1:
The patent applies local quality by making the protective layer thickness spatially variable: in the light-emitting region, the protective layer has a first thickness to ensure device protection and electroluminescence function, while in the non-light-emitting region, the protective layer has a second thickness that is less than the first thickness to maximize light transmittance. This gradual thickness transition at the interface reduces the gradient effect that would otherwise cause cathode breakdown, thereby simultaneously improving transparency and maintaining cathode integrity.
Solution Approach 2:
The patent changes the physical parameter of protective layer thickness across different regions of the display device. By adjusting the thickness parameter from a first thickness in the light-emitting region to a second thickness in the non-light-emitting region, the patent optimizes both the protective function and light transmittance. This parameter change approach allows the device to achieve high transparency in transparent display areas while maintaining sufficient protection in functional areas.
2Reliability
If the thickness of the cathode is increased to improve device performance, then reliability is improved, but the transmittance of the light-emitting region is reduced
Solution Approach 1:
The patent applies local quality by differentiating the protective layer thickness in different functional regions. The first thickness in the light-emitting region is optimized to balance protection and transmittance, while the second thickness in the non-light-emitting region is reduced to maximize transparency. This spatial differentiation allows the device to achieve both adequate protection and high light transmittance without requiring a uniformly thick cathode that would compromise transparency.
Data Source
AI summary
The present disclosure provides an organic electroluminescent display substrate and a manufacturing method thereof, and a display device. The organic electroluminescent display substrate includes a base substrate and a plurality of pixel units formed on the base substrate, the pixel unit including a light-emitting region and a non-light-emitting region. An organic electroluminescent structure is formed in the light-emitting region, the organic electroluminescent structure including a first electrode layer, an organic luminescent functional layer and a second electrode layer stacked on the base substrate, the second electrode layer including a first portion in the light-emitting region and a second portion in the non-light-emitting region, and a plurality of organic/inorganic material layers are provided between the second electrode layer and the base substrate, the plurality of organic/inorganic material layers including at least the organic luminescent functional layer in the light-emitting region and including a transparent material layer in the non-light-emitting regions of parts of pixel units.