Pixel Circuit Capacitor Segmentation for Threshold Voltage Compensation
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Solution Overview
Problem
Conventional pixel circuits face challenges in maintaining the compensating ability of threshold voltage, leading to decreased display quality due to the loss of threshold voltage stored in storage capacitors when the source voltage of the driving transistor changes to the light emitting voltage, and increasing capacitance limits resolution and layout.
Innovation Solution
The proposed pixel design includes two capacitors connected in series between the control electrode and the output electrode of the driving transistor, or a first capacitor between the control electrode and the output electrode of the driving transistor, and a second capacitor between the control electrode and the output electrode of the writing transistor, enhancing the compensating ability of the threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacitance of the storage capacitor is increased to enhance the compensating ability of the threshold voltage, then the compensating ability is improved, but the resolution and layout are limited
Solution Approach 1:
The patent divides the storage capacitor into two separate capacitors (first capacitor and second capacitor) connected in series. This segmentation allows the total capacitance to be distributed across multiple components, achieving the required compensating ability without requiring a single large capacitor that would limit layout and resolution.
2Ease of operation
If the source voltage of the driving transistor changes to the light emitting voltage, then the light emitting element can operate, but the threshold voltage stored in the storage capacitor is lost
Solution Approach 1:
The patent performs preliminary threshold voltage compensation by storing the threshold voltage in two capacitors connected in series before the source voltage changes to the light emitting voltage. This preliminary action ensures that the compensating ability is established in advance, preventing loss of threshold voltage information during the voltage transition.
Data Source
AI summary
A pixel of a display apparatus includes a light emitting element, a first transistor, a second transistor, a first capacitor, and a second capacitor. The first transistor applies a driving current to the light emitting element. The second transistor transmits a data voltage. The first capacitor includes a first end electrically connected to a control electrode of the first transistor, and a second end electrically connected to an output electrode of the second transistor. The second capacitor includes a first end electrically connected to the output electrode of the second transistor, and a second end electrically connected to an output electrode of the first transistor.