Oxide-Semiconductor Pixel Circuit Layout for Stable OLED Driving
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Solution Overview
Problem
Existing organic light emitting devices face challenges in maintaining stable driving, improving reliability, and reducing power consumption, particularly as the number of pixels increases and aperture ratios decrease.
Innovation Solution
The display device incorporates a driving transistor with a polycrystalline semiconductor and additional transistors with oxide semiconductors, along with specific layer configurations and electrical connections to stabilize operation and enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels is increased to increase resolution, then display quality is improved, but aperture ratio is reduced and power consumption increases
Solution Approach 1:
The patent changes the material parameter of the transistor from conventional semiconductor to oxide semiconductor, which fundamentally alters the electrical characteristics to achieve ultra-low leakage current. This parameter change enables high-resolution displays to consume less power by reducing the standby current of each pixel transistor.
Solution Approach 2:
The patent employs oxide semiconductor materials (such as IGZO - indium gallium zinc oxide) that combine the advantages of both conventional semiconductors and insulators, creating a composite material system that provides both high mobility for active driving and extremely low leakage for power saving, thus resolving the contradiction between high resolution and power consumption.
2Measurement precision
If the aperture ratio is reduced to increase pixel density, then resolution is improved, but driving stability deteriorates and reliability decreases
Solution Approach 1:
The patent changes the transistor material to oxide semiconductor, which provides more stable electrical characteristics and lower variability. This parameter change ensures that even with reduced aperture ratios, the transistors maintain stable threshold voltages and low leakage currents, thereby preserving driving stability and reliability at high resolutions.
3Illumination intensity
If current density is increased to improve display performance, then brightness is improved, but stains are generated and element reliability deteriorates
Solution Approach 1:
The patent utilizes the stable electrical characteristics of oxide semiconductor transistors to implement more precise current control in the display driving circuit. The low leakage current and high stability of oxide semiconductors provide inherent feedback control, enabling accurate current regulation that prevents over-current conditions which cause stains and reliability issues.
Data Source
AI summary
A display device includes a polycrystalline semiconductor including a channel and electrodes of a driving transistor; a gate electrode of the driving transistor on the channel of the driving transistor; a first storage electrode on the gate electrode of the driving transistor; a light blocking layer of a first transistor and a light blocking layer of a second transistor; an oxide semiconductor including a channel and electrodes of the first transistor, and a channel and electrodes of the second transistor; a gate electrode of the first transistor on the channel of the first transistor; and a gate electrode of the second transistor on the channel of the second transistor. The light blocking layer of the first transistor and the first storage electrode are on a same layer, and the light blocking layer of the second transistor and the gate electrode of the driving transistor are on a same layer.