Pixel Circuit Body Potential Adjustment for Display Uniformity
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Solution Overview
Problem
Existing pixel drive circuits suffer from poor display uniformity due to random offsets caused by individual differences, leading to significant amplification of small signals and display mura, limiting their application in high-brightness and high-resolution displays.
Innovation Solution
A pixel circuit design incorporating a pixel drive circuit and a pixel compensation circuit, where the output terminal of the drive transistor is connected to the pixel compensation circuit through an organic light-emitting element, with a body potential that is greater than the cathode potential and crossover voltage, increasing the source-substrate voltage potential and reducing the effect of random offsets on the drive current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gain between output and input is increased to amplify small signals, then the signal amplification capability is improved, but the random offset caused by individual differences of drive circuits is significantly amplified, resulting in poor uniformity and display mura
Solution Approach 1:
The patent changes the body potential parameter from ground potential to a positive potential (0.5V-2.0V), which modifies the threshold voltage and transconductance characteristics of the drive transistor. This parameter change allows the circuit to operate with reduced gain, thereby suppressing the amplification of random offsets while maintaining adequate signal amplification for display applications.
Solution Approach 2:
The patent introduces a body potential adjustment mechanism that allows dynamic control of the body potential based on driving current magnitude. The body potential is set to 0.5V-2.0V for high current regions and can be adjusted for different operating conditions, enabling adaptive suppression of random offset effects across varying display brightness levels.
2Illumination intensity
If the drive current is increased to achieve high-brightness display, then the brightness output is improved, but the random offset effect is significantly amplified, leading to poor display uniformity
Solution Approach 1:
The patent applies parameter changes by setting the body potential to a positive value (0.5V-2.0V) rather than ground potential. This modifies the transistor characteristics to reduce the gain in the high-current region, thereby suppressing the amplification of random offsets even when drive current is increased for high-brightness display operation.
Solution Approach 2:
The patent implements feedback by monitoring the driving current magnitude and adjusting the body potential accordingly. The body potential is set to 0.5V-2.0V based on the current region, creating a feedback mechanism that dynamically suppresses random offset effects across different brightness levels to maintain display uniformity.
3Device complexity
If the body potential is set to ground potential, then the circuit design is simple, but the random offset caused by individual differences cannot be effectively suppressed
Solution Approach 1:
The patent changes the body potential parameter from ground potential to a positive potential (0.5V-2.0V). This parameter modification provides effective suppression of random offsets through modified transistor characteristics, while the implementation remains relatively simple by utilizing existing potential distribution structures in the display panel.
Data Source
AI summary
Provided are a pixel circuit, a silicon-based display panel, and a display device. The pixel circuit includes a pixel drive circuit and a pixel compensation circuit; the pixel drive circuit includes a drive transistor and an organic light-emitting element; the drive transistor includes an output terminal and a body terminal, where the output terminal is connected to an anode of the organic light-emitting element, and the body terminal is connected to a body signal input terminal and configured to receive a body potential inputted from the body signal input terminal, the body potential being fixed; and a cathode of the organic light-emitting element is connected to the pixel compensation circuit at a first node, a potential of the first node is a cathode potential, and the cathode potential Vcom, a crossover voltage Voled of the organic light-emitting element, and the body potential Vbody satisfy that Vcom+Voled>Vbody.