N-Type Pixel Circuit for Compact Threshold Compensation
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Solution Overview
Problem
Conventional pixel circuits driven in pulse width modulation with threshold voltage compensation require 19 or more transistors and 3 or more capacitors, limiting their application to ultra-high resolution displays and suffering from afterimage, response time, and luminance degradation issues due to P-type transistors.
Innovation Solution
A pixel circuit design using fewer transistors, specifically N-type transistors, with internal threshold voltage compensation, allowing integration into ultra-high resolution displays and enhancing performance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pixel circuits use 19 or more transistors and 3 or more capacitors for threshold voltage compensation, then threshold voltage compensation is achieved, but device complexity and integration difficulty increase
Solution Approach 1:
The patent extracts and eliminates redundant transistors and capacitors from the conventional pixel circuit structure. By reconfiguring the circuit topology and removing unnecessary components while retaining the essential threshold voltage compensation function, the design achieves simplification without sacrificing reliability.
Solution Approach 2:
The patent merges multiple functions into fewer transistors by optimizing the circuit architecture. Transistors are strategically combined to perform multiple roles simultaneously, reducing the total component count while maintaining the threshold voltage compensation capability.
2Ease of manufacture
If P-type transistors are used in pulse width modulation pixel circuits, then conventional design is achieved, but afterimage characteristic, response time, and luminance-changing-rate deteriorate
Solution Approach 1:
The patent changes the fundamental parameter of transistor type from P-type to N-type. This parameter change fundamentally improves the electrical characteristics including response time, afterimage reduction, and luminance-changing-rate while maintaining compatibility with the pulse width modulation driving method.
3Measurement precision
If pixel circuits are designed for ultra-high resolution display, then resolution is improved, but integration becomes more difficult due to component count
Solution Approach 1:
By removing redundant transistors and capacitors from the pixel circuit, the patent reduces the area occupied by each pixel. This extraction of unnecessary components enables higher pixel density and ultra-high resolution display while maintaining manageable integration complexity.
Solution Approach 2:
The simplified circuit design uses multi-functional transistors that can serve multiple purposes within the pixel circuit, enabling the same compact structure to support ultra-high resolution requirements across different display applications.
Data Source
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AI summary
A pixel circuit includes a first transistor (T1) including a control electrode connected to a first node (N1), a first electrode connected to a second node (N2), and a second electrode connected to a third node (N3), a second transistor (T2) connected to the first node and the second node, a third transistor (T3) configured to apply a data voltage (VDATA) to the first transistor, a seventh transistor (T7) connected to a fourth node (N4), and configured to apply a driving current to a light-emitting element (EE), a ninth transistor (T9) configured to apply a constant-current voltage to the fourth node, and the light-emitting element configured to emit a light based on the data voltage and the constant-current voltage, wherein the first transistor, the second transistor, the third transistor, the seventh transistor, and the ninth transistor include N-type transistors.