OLED Display Substrate Opening Layout to Prevent FMM Spacer Contact
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Solution Overview
Problem
The contact between the opening edge of a fine metal mask (FMM) and the spacer during the evaporation process in OLED display manufacturing leads to scratches on the spacer and generates foreign bodies like particles, affecting the stability and reliability of the OLED display substrate.
Innovation Solution
The display substrate design includes a pixel defining layer with offset opening group rows and a spacer positioned between them, where the extension lines of the openings' long edges are misaligned, keeping the FMM edge away from the spacer, thereby preventing contact and particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the FMM is positioned close to the spacer to improve evaporation precision, then the manufacturing precision is improved, but the FMM edge contacts the spacer causing scratches and particle generation, worsening the reliability
Solution Approach 1:
The patent applies asymmetry by designing the spacer with a non-symmetric cross-sectional shape where one side has a larger projection area than the other. This asymmetric design creates an offset between the spacer's center of mass and its geometric center, allowing the FMM to be positioned asymmetrically relative to the spacer. This asymmetric positioning maintains the required clearance to prevent contact while achieving precise evaporation alignment, thus resolving the contradiction between manufacturing precision and reliability.
Solution Approach 2:
The patent resolves the contact issue by transitioning from a two-dimensional planar positioning problem to a three-dimensional spatial arrangement. By designing the spacer with different projection areas in different directions (asymmetric cross-section), the solution creates additional spatial degrees of freedom. This allows the FMM to be positioned in a specific three-dimensional configuration that maintains clearance from the spacer while achieving precise evaporation alignment, thus preventing contact while maintaining manufacturing precision.
2Ease of manufacture
If the FMM edge contacts the spacer during evaporation, then the evaporation process is simplified, but particle generation increases, worsening the product quality
Solution Approach 1:
The patent applies preliminary action by pre-positioning the spacer with an asymmetric cross-sectional shape before the evaporation process. This preliminary asymmetric design pre-establishes the optimal spatial relationship between the spacer and the intended FMM position. When the FMM is subsequently positioned, the asymmetric spacer geometry automatically ensures the required clearance is maintained, preventing contact and particle generation while keeping the evaporation process simple. The harmful effect is prevented in advance through the preliminary asymmetric结构设计.
3Reliability
If the spacer is positioned to prevent FMM contact, then the reliability is improved, but the positioning complexity increases, worsening the device complexity
Solution Approach 1:
The patent resolves the contradiction by using asymmetry in the spacer's cross-sectional shape rather than adding complex positioning mechanisms. The asymmetric design (with different projection areas on different sides) inherently encodes the required clearance information in the spacer's geometry itself. This eliminates the need for additional positioning structures or complex alignment mechanisms, maintaining device simplicity while ensuring reliable clearance between the FMM and spacer.
Solution Approach 2:
The patent applies parameter changes by modifying the geometric parameters of the spacer, specifically its cross-sectional shape and projection areas. By changing these geometric parameters to create an asymmetric configuration, the spacer inherently defines the optimal positioning relationship with the FMM. This parameter-based solution achieves reliable clearance positioning without adding structural complexity, as the positioning information is embedded in the spacer's geometric parameters rather than requiring additional positioning mechanisms.
Data Source
AI summary
A display substrate and a display device are disclosed. In the display substrate, a plurality of openings include a plurality of opening groups, the plurality of opening groups include a plurality of opening group rows, each of the opening groups includes a first opening and a second opening, the plurality of opening group rows includes a first opening group row and a second opening group row, the spacer is located between the first opening of the first opening group row and the second opening of the second opening group row, an orthographic projection of the first opening includes a first long edge, and an orthographic projection of the second opening includes a second long edge, the first long edge is parallel to the second long edge, an extension line of the first long edge is misaligned from an extension line of the second long edge.