Display Device Semiconductor Thickness Variation for Low-Frequency Flicker
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Solution Overview
Problem
Display devices with polycrystalline semiconductors experience flickering when driven at low frequencies due to increased leakage currents.
Innovation Solution
The display device incorporates a semiconductor layer with varying thicknesses, featuring a first portion with a specific thickness and a second portion thinner than the first, positioned between certain transistor electrodes to reduce leakage currents, thereby preventing flickering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform thickness semiconductor layer is used, then the manufacturing process is simple, but leakage current increases causing flicker at low frequencies
Solution Approach 1:
The semiconductor layer is designed with different thicknesses in different regions: a first thickness in the first area and a second thickness (greater than the first) in the second area. This local variation in thickness provides different electrical characteristics in different regions, reducing leakage current and preventing flicker while maintaining manufacturing feasibility through a single-layer structure.
2Reliability
If the semiconductor layer thickness is increased, then leakage current is reduced, but the area occupied by the transistor increases
Solution Approach 1:
Instead of uniformly increasing the semiconductor layer thickness across the entire transistor, the invention applies increased thickness only in the second area where leakage current occurs. This localized approach reduces leakage current effectively while minimizing the increase in overall transistor area, as the thicker region is confined to a specific portion rather than the entire device footprint.
3Reliability
If additional semiconductor layers are added to reduce leakage current, then display quality improves, but manufacturing cost increases
Solution Approach 1:
The invention achieves improved display quality by creating a thicker region within a single semiconductor layer rather than adding multiple separate layers. This is accomplished through selective epitaxial growth or other thickness-control techniques during the formation of one continuous semiconductor layer, thereby reducing manufacturing complexity and cost compared to stacking multiple layers while still achieving the leakage current reduction needed for high-quality display performance.
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
The solution enables stable operation at low frequencies without flickering, improving display quality and reducing manufacturing costs by minimizing the need for additional semiconductor layers.
Implementation Method 1
the semiconductor layer includes a first portion having a first thickness and a second portion having a second thickness thinner than the first thickness, and the driving transistor is disposed in the first portion of the semiconductor layer
Data Source
AI summary
An embodiment provides a display device including: a substrate; a plurality of transistors disposed on the substrate, each of the plurality of transistors including a semiconductor layer disposed on the substrate, and a gate electrode disposed on the semiconductor layer; and a light emitting element positioned on the data conductor layer, wherein the plurality of transistors include a driving transistor that transmits a driving voltage to the light emitting element and a compensation transistor that is turned on in response to a scan signal, the semiconductor layer includes a first portion having a first thickness and a second portion having a second thickness thinner than the first thickness, and the driving transistor is disposed in the first portion of the semiconductor layer.