Pixel Driving Circuit With Reversed-Phase Threshold Compensation
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Solution Overview
Problem
Organic light emitting diode displays suffer from non-uniformity in emitted light due to variations in threshold voltage of driving transistors, necessitating improved compensation methods to enhance display quality.
Innovation Solution
A pixel driving circuit with a first circuit configured to compensate for threshold voltage variations in driving transistors, utilizing light emitting control signals of reversed phases and multiple transistor configurations to operate in compensation or non-compensation modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If internal compensation methods are used to compensate for threshold voltage variations, then display uniformity is improved, but device complexity increases
Solution Approach 1:
The pixel driving circuit is divided into multiple functional circuits: a first circuit for threshold voltage compensation, a second circuit for light emitting control, and third circuits for driving the light emitting element. This segmentation allows each circuit to perform a specific function, achieving effective compensation while maintaining clear circuit architecture and manageable complexity.
Solution Approach 2:
The light emitting control signals are designed with reversed phases that dynamically adjust the operating states of transistors in the first and second circuits. By switching between different phase states, the circuit adapts to threshold voltage variations and optimizes compensation effectiveness without requiring complex fixed circuit designs.
2Reliability
If multiple control signal lines with reversed phases are used, then compensation effectiveness is improved, but device complexity increases
Solution Approach 1:
Instead of using complex multi-level control signals, the invention employs light emitting control signals with reversed phases (inverted logic states). This inversion approach simplifies the signal generation while achieving effective control over the compensation process, as the reversed phases naturally create complementary switching actions in paired transistors.
Solution Approach 2:
The light emitting control signal lines serve multiple functions: they control the light emitting timing, enable threshold voltage compensation, and coordinate the operation of multiple transistors simultaneously. This multi-functionality reduces the need for separate dedicated control lines, thereby limiting the increase in device complexity.
3Manufacturing precision
If compensation mode is activated, then display quality is improved, but power consumption increases due to additional control signals
Solution Approach 1:
The compensation operation is performed periodically through frame-by-frame updating of the light emitting control signals. During each frame period, the reversed phase signals enable compensation for threshold voltage variations, while during other periods the circuit operates in a lower-power state. This periodic action achieves compensation effectiveness while managing overall power consumption.
Solution Approach 2:
The circuit design allows for discarding excess power consumption during non-compensation periods by putting certain circuits into low-power states. The compensation function is recovered and activated only when needed through the light emitting control signals, thereby achieving display quality improvement without continuous high power consumption.
Data Source
AI summary
A pixel driving circuit is provided. The pixel driving circuit includes a first circuit, a second circuit, and one or more third circuits. The first circuit is configured to compensate for a variation in a threshold voltage in a driving transistor in the one or more third circuits. The first circuit is coupled to a first control signal line, a second control signal line, a first light emitting control signal line, and a second light emitting control signal line. The second circuit is coupled to the first light emitting control signal line and the second light emitting control signal line. The first light emitting control signal line and the second light emitting control signal line are configured to transmit light emitting control signals having reversed phases.