Pixel Circuit With Shunt Branch for Low-Grayscale Uniformity
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Solution Overview
Problem
Current OLED display products suffer from uneven display brightness, particularly at low grayscale and low brightness, due to fluctuations in transistor characteristics affecting driving current and image quality.
Innovation Solution
A pixel circuit with a driving module and a shunt branch that shunts part of the driving current to a reference voltage signal line, increasing the total current flow and maintaining expected brightness, thereby improving brightness uniformity and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pixel circuits are used without shunt branch, then device complexity is low, but brightness uniformity deteriorates at low grayscale and low brightness due to transistor characteristic fluctuations
Solution Approach 1:
The pixel circuit is segmented by introducing a shunt branch that separates the driving current path into two parallel paths: one through the light-emitting element and another through the shunt branch to the reference voltage signal line. This segmentation allows the driving module to provide a larger total current while the light-emitting element receives a stable current less affected by transistor fluctuations, thereby improving brightness uniformity at low grayscale without significantly increasing overall circuit complexity.
2Reliability
If driving current is increased to compensate for transistor fluctuations, then brightness uniformity improves, but power consumption increases
Solution Approach 1:
The shunt branch acts as an intermediary that provides an alternative current path to the reference voltage signal line. By introducing this intermediate pathway, the circuit can maintain a larger total driving current from the driving module while the actual current through the light-emitting element remains optimized for power efficiency. The shunt branch mediates between the need for high total current (for stability) and low individual component current (for power savings).
Data Source
AI summary
A pixel circuit and a display module, and relate to the field of display panels. The pixel circuit includes: a driving module electrically connected to a first electrode of a light-emitting element and configured to drive the light-emitting element to emit light; and a shunt branch. A first terminal of the shunt branch is electrically connected to the first electrode of the light-emitting element, a second terminal of the shunt branch is electrically connected to a first reference voltage signal line, and the shunt branch is configured to transmit part of a driving current provided by the driving module to the first reference voltage signal line.