Variable Thickness Bank Structure for Display Device
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Solution Overview
Problem
Display devices face issues with color conversion layers overflowing into adjacent pixels and stain defects due to air bubbles and photoresist deformation during the manufacturing process.
Innovation Solution
A display device design featuring a bank structure with a thinner first area and a thicker second area in the non-light emitting area, which accommodates the color conversion layer and compensates for steps, preventing overflow and air bubbles, and minimizing photoresist bursting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a uniform thickness bank structure is used, then the manufacturing process is simple, but the color conversion layer overflows into adjacent pixels causing stain defects
Solution Approach 1:
The bank structure is designed with different thicknesses in different regions: a first thickness in the first area and a second thickness in the second area. This local quality variation allows the bank to accommodate the color conversion layer's overflow tendency in specific areas while maintaining structural simplicity, thereby preventing stain defects without requiring a completely complex structure.
Solution Approach 2:
The solution moves from a two-dimensional planar bank structure to a three-dimensional structure with varying thickness. By introducing the thickness dimension, the bank can provide localized support and containment for the color conversion layer, enabling precise positioning control without increasing planar complexity.
2Manufacturing precision
If the bank thickness is increased to prevent overflow, then color conversion layer containment improves, but air bubbles form due to photoresist deformation
Solution Approach 1:
Instead of uniformly increasing bank thickness, the invention applies thickness variation locally: the first area has a first thickness while the second area has a second thickness. This localized approach provides sufficient containment where needed while avoiding excessive thickness that would cause photoresist deformation and air bubble formation in other areas.
Solution Approach 2:
The bank provides partial containment action rather than excessive uniform containment. By using different thicknesses in different areas, the bank provides just enough support to prevent overflow in critical areas without over-containment that would deform the photoresist and create air bubbles.
Data Source
AI summary
A display device includes pixels including a light emitting area and a non-light emitting area; light emitting elements disposed in the light emitting area; and a bank disposed in the non-light emitting area. The bank includes an opening overlapping the light emitting area in a plan view; a first area spaced apart from the opening; and a second area surrounding the opening and the first area, and a thickness of the second area is greater than a thickness of the first area.