Display Panel Alignment Mark Structure for Precise Mask Registration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display device fabrication processes face challenges in achieving accurate alignment between the display panel and the mask during the deposition of metal wires or insulating layers, leading to misalignment issues.
Innovation Solution
The display device incorporates a planarization layer with a stepped portion overlapping the alignment mark, and a bank material with varying thickness and light transmittance to facilitate precise alignment recognition using a camera, combined with a metal alignment mark for enhanced visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a uniform thickness planarization layer is used, then the fabrication process is simple, but alignment accuracy between display panel and mask deteriorates
Solution Approach 1:
The planarization layer is designed with different thicknesses in different regions: a first thickness in the alignment mark region and a second thickness in the display region. This local variation in thickness provides selective planarization that improves alignment accuracy in the critical alignment mark region while maintaining display quality in the display region.
2Manufacturing precision
If the planarization layer thickness is increased for better planarity, then surface flatness improves, but alignment mark visibility for camera recognition deteriorates
Solution Approach 1:
The planarization layer has a first thickness in the alignment mark region and a second thickness in the display region, where the first thickness is greater than the second thickness. This local differentiation ensures sufficient planarity for camera recognition in the alignment mark region while maintaining appropriate visibility characteristics.
3Reliability
If a thick bank material is used for complete coverage, then protection and insulation improve, but light transmittance for alignment mark recognition deteriorates
Solution Approach 1:
The bank material is configured with different thicknesses: a first thickness in the alignment mark region and a second thickness in the display region. The first thickness is less than the second thickness, allowing light to pass through the bank material in the alignment mark region for camera recognition while providing sufficient coverage and protection in the display region.
Data Source
AI summary
According to some embodiments of the present disclosure, a display device includes: a substrate; a planarization layer on the substrate; a first alignment mark in a non-display area of the substrate; a first electrode and a second electrode in a display area of the substrate; a light emitting element electrically connected to the first electrode and the second electrode; a wavelength conversion layer on the light emitting element; a first bank on at least a part of the first electrode; and a second bank on the first bank to be around the wavelength conversion layer. A thickness of a part of the planarization layer that overlaps the first alignment mark in a thickness direction of the substrate is greater than a thickness of a part of the planarization layer that overlaps the first electrode and the second electrode in the thickness direction of the substrate.