Reverse-Taper Pixel Structures for Lower-Cost Display Manufacturing
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Solution Overview
Problem
Existing display apparatus manufacturing processes are costly and time-consuming, particularly due to complex pixel structures and materials used.
Innovation Solution
The display apparatus incorporates a pixel-defining layer with reverse taper openings, intermediate layers, and auxiliary electrode patterns, along with dummy patterns and layers, to simplify the manufacturing process and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex pixel structures and materials are used in display apparatus manufacturing, then display quality and performance are improved, but manufacturing cost and time increase
Solution Approach 1:
The pixel-defining layer is divided into multiple pattern layers (first pattern layer, second pattern layer, third pattern layer) that are formed separately and then combined. This segmentation allows each layer to be optimized independently for its specific function while simplifying the overall manufacturing process by breaking down the complex pixel structure into manageable segments that can be produced using standard photolithography techniques.
Solution Approach 2:
The pixel-defining layer patterns are formed in advance before the light-emitting layer is deposited. The first, second, and third pattern layers are sequentially formed with specific openings positioned to define the pixel structure beforehand, allowing subsequent layers to be deposited without requiring complex in-situ patterning, thus reducing manufacturing complexity and time.
2Ease of manufacture
If traditional pixel structures are used, then manufacturing process is simpler, but manufacturing cost and time increase
Solution Approach 1:
Multiple functional patterns (pixel-defining patterns, electrode patterns, and structural support patterns) are merged into a single integrated pixel-defining layer structure consisting of three pattern layers. This merging eliminates the need for separate manufacturing processes for each pattern type, reducing the total number of photolithography steps and improving manufacturing efficiency while maintaining process simplicity.
Solution Approach 2:
The pixel-defining layer with its three pattern layers serves multiple functions simultaneously: it defines pixel boundaries, positions electrodes, supports the light-emitting layer, and creates the reverse taper structure for optimal light extraction. This multi-functionality reduces the need for additional specialized components and processes, thereby improving productivity without sacrificing ease of manufacture.
3Productivity
If pixel-defining layer with reverse taper and multiple patterns is implemented, then manufacturing efficiency is improved, but structural complexity increases
Solution Approach 1:
The reverse taper pixel-defining layer is segmented into three distinct pattern layers, each with specific opening positions and functions. This segmentation reduces the complexity of forming the complete structure in a single step by breaking it down into sequential, standardized photolithography operations, thereby improving manufacturing efficiency while managing structural complexity through systematic decomposition.
Solution Approach 2:
The pixel-defining layer is designed with a reverse taper geometry that extends in the vertical dimension, creating openings that are narrower at the top and wider at the bottom. This dimensional approach allows the same planar pattern to achieve multiple functions (electrode positioning, light extraction optimization, structural support) without increasing lateral complexity, thus improving manufacturing efficiency.
4Ease of manufacture
If dummy patterns and auxiliary electrode patterns are added, then manufacturing process is optimized, but device complexity increases
Solution Approach 1:
Dummy patterns are formed in advance during the same photolithography process as the functional pixel-defining patterns. These dummy patterns are positioned in non-display areas and serve to optimize the manufacturing process by providing process control references and ensuring uniform deposition conditions, thereby simplifying the overall manufacturing optimization without requiring separate additional process steps.
Solution Approach 2:
The auxiliary electrode patterns are formed as copies of the main electrode patterns but positioned in different locations (such as on the opposite electrode side). These copied patterns simplify manufacturing by using the same photolithography masks and deposition processes, optimizing the manufacturing process through pattern repetition while managing device complexity through spatial separation of identical structures.
Data Source
AI summary
A display apparatus includes: a pixel-defining layer on first and second pixel electrodes, the pixel defining layer including first and second openings exposing a portion of the first and second pixel electrodes, respectively, and having a reverse taper shape; first and second intermediate layers respectively in the first and second openings; first and second opposite electrodes respectively on the first and second intermediate layers; a first dummy pattern and a second dummy pattern each on an upper surface of the pixel-defining layer; a first auxiliary electrode pattern covering the first opposite electrode, a lateral surface of the pixel-defining layer, and the first dummy pattern; a second auxiliary electrode pattern covering the second opposite electrode, a lateral surface of the pixel-defining layer, and the second dummy pattern; and an auxiliary electrode layer on the first auxiliary electrode pattern, the second auxiliary electrode pattern, and the pixel-defining layer.