Light-Emitting Display Pixel Circuit With Low-Leakage Channel Sizing
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Solution Overview
Problem
Light emitting display devices using polycrystalline semiconductors experience flicker when driven at low frequencies due to high leakage currents, which affect display luminance and image quality.
Innovation Solution
The design includes transistors with channels in a polycrystalline semiconductor layer, where the width and length of specific transistors are optimized to reduce leakage currents, and a gate insulating film with a thickness of 800-1200 Å, formed by processes such as ozone cleaning, hydrogen fluoride treatment, and plasma treatment to minimize channel size and protrusions, allowing for low-frequency operation without flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transistors with larger channel dimensions are used, then manufacturing precision is easier to achieve, but leakage current increases causing flicker at low frequencies
Solution Approach 1:
The patent applies parameter changes by optimizing the channel width and length of specific transistors (T3 and T4) to precise ranges (1-2 μm width, 1-2.5 μm length) to reduce leakage current. This dimensional parameter optimization enables low-frequency operation without flicker while maintaining manufacturability through well-controlled fabrication processes.
2Object-generated harmful factors
If channel size of transistors is reduced, then leakage current decreases eliminating flicker, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by differentiating channel dimensions across different transistor types within the same pixel circuit. Transistors T3 and T4 have specifically optimized small channel dimensions (1-2 μm width, 1-2.5 μm length) to minimize leakage current, while other transistors may have different dimensions suited to their functions. This localized optimization eliminates flicker without requiring all transistors to meet stringent dimensional constraints.
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 configuration ensures that the light emitting display device can operate at low frequencies without flicker, maintaining display luminance and improving image quality by controlling leakage currents and channel sizes of transistors.
Implementation Method 1
formed by processes such as ozone cleaning, hydrogen fluoride treatment, and plasma treatment
Implementation Method 2
formed by processes such as ozone cleaning, hydrogen fluoride treatment, and plasma treatment
Data Source
AI summary
A light emitting display device includes: a light emitting element; a second transistor connected to a scan line; a first transistor which applies a current to the light emitting element; a capacitor connected to a gate electrode of the first transistor; and a third transistor connected to an output electrode of the first transistor and the gate electrode of the first transistor. Channels of the second transistor, the first transistor, and the third transistor are disposed in a polycrystalline semiconductor layer, and a width of a channel of the third transistor is in a range of about 1 μm to about 2 μm, and a length of the channel of the third transistor is in a range of about 1 μm to about 2.5 μm.