OLED Display Power Line Symmetry for Stitch Defect Prevention
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Solution Overview
Problem
The existing OLED display devices face challenges in achieving high aperture ratio and resolution with low production costs, particularly due to stitching exposure defects at the boundaries between chip-on-films (COFs) and complex line arrangements, which complicate the design and increase production costs.
Innovation Solution
The OLED display device features a substrate with symmetric power line arrangements and drive integrated circuits connected to power lines, allowing for a method of fabricating the device by dividing the substrate into shot regions and using overlapping regions to prevent stitch defects, enabling easier design and assembly with reduced production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If stitching exposure is performed at the boundary between first and second COFs, then large size OLED display device can be fabricated, but stitch defects occur at the boundary region
Solution Approach 1:
The substrate is divided into first and second shot regions corresponding to first and second COFs, with a boundary region between them. The exposure process is segmented into first and second shots performed at different positions, allowing precise control of the exposure boundary to prevent stitch defects while enabling large substrate fabrication.
2Reliability
If asymmetric line arrangement is used to connect pads to drive ICs, then electrical connections can be established, but design complexity of driving PCB increases
Solution Approach 1:
The patent employs asymmetric line arrangement where power lines, data lines, and reference voltage lines are positioned differently in first and second COFs. The first COF has lines arranged in one sequence while the second COF has lines arranged in a different sequence, allowing simplified PCB design while maintaining reliable electrical connections to drive ICs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in an OLED display device with improved resolution and size capabilities, reduced production costs, and simplified design complexities, preventing stitch defects and enhancing display quality.
Implementation Method 1
performing a first shot to the photoresist layer using the first exposing mask in the first shot region; performing a second shot to the photoresist layer using the second exposing mask in the second shot region and the first blade; developing the photoresist layer to form a photoresist pattern
Implementation Method 2
an organic light emitting diode (OLED) display device... an organic emitting diode in each of the red, green, blue and white pixel regions
Data Source
AI summary
An organic light emitting diode display device includes a substrate including a display and non-display regions at a periphery of the display region with red, green, blue and white pixel regions as one pixel group formed in the display region, and the display region divided into a first region and a second region; an organic emitting diode in each of the red, green, blue and white pixel regions; first to third power lines respectively disposed at an end of the first region, at an opposite end of the second region and a boundary of the first and second regions and connected to the organic emitting diode; a first drive integrated circuit connected to the first and third power lines; and a second drive integrated circuit connected to the second and third power lines, wherein the first and second regions are symmetric with respect to the third power line.