Bottom-Emission Display Stack With Integrated Reflective Layer
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Solution Overview
Problem
Current display devices face challenges in achieving efficient light emission and manufacturing productivity due to complex structures requiring multiple masks and layers, which affect efficiency and productivity.
Innovation Solution
A display device structure is proposed where a substrate has a display element layer with a light emitting element and a pixel circuit layer stacked successively, reducing the number of masks needed by eliminating separate layers for bank formation and reflective layers, and using transparent electrodes with higher light transmittance to enhance bottom emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If separate layers for bank formation and reflective layers are used, then light emission efficiency is improved, but device complexity and manufacturing process complexity increase
Solution Approach 1:
The patent combines the bank formation layer and reflective layer into a single integrated layer structure. The bank layer is formed with reflective properties, eliminating the need for separate reflective layers while maintaining both the light guiding function and light reflection function. This integration reduces the number of masks and layers required in the manufacturing process.
Solution Approach 2:
The bank layer is designed to serve multiple functions simultaneously: it acts as a structural boundary element (bank), a light reflecting surface, and a light guiding element. By making the bank layer multi-functional, the patent eliminates the need for separate dedicated reflective layers and simplifies the overall device structure.
2Illumination intensity
If multiple masks and layers are used, then light emission efficiency is improved, but manufacturing productivity decreases
Solution Approach 1:
The patent merges multiple manufacturing steps into fewer steps by combining the formation of banks and reflective layers into a single deposition process. This reduces the number of photolithography masks required and decreases the total number of manufacturing steps, thereby improving manufacturing productivity while maintaining light emission efficiency.
3Reliability
If traditional electrode structures are used, then electrical connection is achieved, but light transmittance is reduced
Solution Approach 1:
The patent changes the material parameters of the electrodes by using transparent conductive materials with optimized optical and electrical properties. By selecting materials and adjusting their thickness and composition, the electrodes achieve both sufficient electrical conductivity for reliable connections and high optical transmittance for improved light emission efficiency.
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 structure simplifies the manufacturing process, reduces product loss, and enhances light emission efficiency by allowing for effective light collection and emission towards the substrate surface.
Implementation Method 1
The pixel circuit layer may include a reflective layer disposed on the display element layer and overlapping the light emitting element... The reflective layer may reflect the light emitted from the light emitting element toward a second surface of the substrate
Data Source
AI summary
A display device includes a substrate, a display element layer disposed on a first surface of the substrate and including a light emitting element that emits light, and a pixel circuit layer disposed on the display element layer and including a transistor electrically connected to the light emitting element. The display element layer includes a first contact electrode electrically connected to a first end of the light emitting element, and a second contact electrode electrically connected to a second end of the light emitting element. The pixel circuit layer includes a reflective layer disposed on the display element layer and overlapping the light emitting element. One of the first contact electrode and the second contact electrode is electrically connected to the transistor. The reflective layer reflects the light emitted from the light emitting element toward a second surface of the substrate.