OLED Display Spacers With Asymmetric Opening Extensions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional OLED displays with spacers do not effectively minimize substrate interference with the organic emission layer, as the spacers are not designed to consider the shape of the openings in the pixel defining layer, leading to suboptimal area ratios and potential interference issues.
Innovation Solution
The OLED display incorporates spacers on the pixel defining layer, with specific shapes and arrangements of openings that increase the area ratio of spacers, optimizing their placement to reduce substrate interference and enhance the aperture ratio, using a design where the spacers are rectangles bisected by the sides of a virtual square, and the openings have distinct polygonal shapes such as octagons, hexagons, and quadrilaterals to accommodate different color-emitting layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If spacers are simply disposed on an unopened portion of the pixel defining layer without regard to the shape of the opening, then the device complexity is reduced and ease of manufacture is improved, but the substrate interference with the organic emission layer is not effectively minimized and the area ratio of spacers is suboptimal
Solution Approach 1:
The spacer is designed with different local qualities by extending it into the opening based on the specific shape of the opening (circular, rectangular, or triangular). This allows the spacer to provide localized support exactly where needed to prevent substrate interference, while maintaining manufacturing simplicity through a standardized extension pattern that adapts to different opening shapes.
2Reliability
If the area ratio of spacers is increased to minimize substrate interference, then the reliability is improved, but the device complexity increases and manufacturing becomes more difficult
Solution Approach 1:
The spacer design employs asymmetry by extending into the opening rather than remaining symmetrically positioned on the unopened portion. This asymmetric extension increases the spacer's area ratio and effectiveness in preventing substrate interference, while the extension distance is controlled to be between 1/4 to 3/4 of the opening's radius or half-diagonal, balancing reliability improvement with manufacturing feasibility.
3Reliability
If the spacer extends into the opening, then the area ratio of spacers is increased to reduce substrate interference, but the aperture ratio may be affected
Solution Approach 1:
The design optimizes the extension distance of the spacer into the opening as a controllable parameter, setting it between 1/4 to 3/4 of the opening's radius or half-diagonal. This parameter optimization ensures that the spacer provides sufficient support to prevent substrate interference while minimizing the impact on the aperture ratio, achieving a balance between reliability and light emission area.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An organic light emitting diode (OLED) display includes: a first electrode (E1) around a center point (CP) of a virtual square (VS); second electrodes (E2) around a first vertex (P1) and a second vertex (P2) diagonal to the first vertex (P2) of the virtual square (VS), the second electrodes /E2) being separated from each other and with the center point (CP) of the virtual square (VS) interposed therebetween; third electrodes (E3) around a third vertex (P3) and a fourth vertex (P4) of the virtual square (VS), the third electrodes (E3) being separated from each other and with the center point (CP) of the virtual square (VS) interposed therebetween; a pixel defining layer (PDL) partially on the first electrode (E1), the second electrodes (E2), and the third electrodes (E3), and partially exposing the first electrode (E1), the second electrodes (E2), and the third electrodes (E3); and four spacers (SP1, SP2, SP3, SP4) disposed as islands on the pixel defining layer (PDL) and corresponding to four sides (V1, V2, V3, V4) of the virtual square (VS).