Flexible Display Wiring Voltage Management for Crack Prevention
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Solution Overview
Problem
Flexible display devices experience quality degradation and image distortion due to luminance differences caused by varying refresh rates in variable refresh rate (VRR) mode, leading to potential cracks in bent portions.
Innovation Solution
A display device design that includes a main region, a bending region, and a sub-region, with a plurality of wirings extending from the sub-region through the bending region to the main region. The wirings include a first wiring, a second wiring, and a dummy wiring, with different substrate portions overlapping each wiring, and physical properties of these substrate portions being distinct.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If variable refresh rate mode is used to reduce power consumption, then power consumption decreases, but luminance difference occurs between pixel circuits causing image distortion and flicker
Solution Approach 1:
The patent applies different voltages to different wirings in different regions (main region vs. bending region) to compensate for luminance differences. Specifically, a first voltage is applied to wirings in the main region while a second voltage (higher than the first) is applied to wirings in the bending region, creating local quality differences that counteract the luminance degradation caused by variable refresh rates.
2Adaptability or versatility
If flexible display device is bent, then device adaptability improves, but cracks occur in bent portion
Solution Approach 1:
The patent creates different physical properties in substrate portions corresponding to different regions. The substrate portion in the bending region has different physical properties (such as different stress characteristics or material composition) compared to the substrate portion in the main region, allowing the bent portion to withstand mechanical stress without cracking while maintaining overall device flexibility.
Solution Approach 2:
The patent preemptively addresses potential crack formation by applying higher voltage to wirings in the bending region before cracks can occur. This preliminary protective measure compensates for the increased stress in bent portions, preventing crack initiation and propagation while maintaining structural integrity during flexing operations.
3Reliability
If different voltages are applied to wirings in bending region, then crack occurrence is prevented, but device complexity increases
Solution Approach 1:
The patent introduces a dummy wiring as an intermediary element between the first wiring and the second wiring. This dummy wiring receives a third voltage (less than the first voltage) and acts as a buffer or mediator that helps manage the voltage distribution across different regions, simplifying the overall voltage management scheme while still achieving crack prevention through the higher voltage applied to the bending region wirings.
Data Source
AI summary
A display device includes a main region, a bending region which is bent from the main region in a thickness direction of a substrate, a sub-region which is connected to the bending region and faces the main region; and a plurality of wirings configured to extend from the sub-region through the bending region to the main region. The plurality of wirings includes: a first wiring to which a first voltage is applied; a second wiring to which a second voltage is applied; and a dummy wiring which receives a third voltage and is between the first wiring and the second wiring. The second voltage is higher than the first voltage, and the third voltage is less than the first voltage.