Alternating Pixel Driver Transistors for OLED Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The electrical characteristics of transistors in display panels, such as threshold voltage and mobility, shift over time, leading to uneven display effects in OLED technology.
Innovation Solution
A pixel driver circuit comprising a control transistor, a first transistor, and a fourth transistor, where the first transistor corresponds to a first driving time period and the fourth transistor corresponds to a second driving time period, alternated to maintain transistors in operational and reverse bias statuses, preventing electrical characteristic shifts and enhancing display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a single transistor continuously drives the light emitting device, then the display can operate continuously, but the transistor's electrical characteristics (threshold voltage and mobility) shift over time causing uneven display
Solution Approach 1:
The patent implements periodic action by alternating between a first transistor and a second transistor in a cyclic manner. The control circuit switches between the first transistor and second transistor based on timing signals, creating periodic operation cycles where each transistor alternates between driving the light emitting device and being in reverse bias. This periodic switching prevents continuous stress on a single transistor, thereby stabilizing electrical characteristics like threshold voltage and mobility over extended operation periods.
Solution Approach 2:
The patent applies dynamics by making the transistor operation dynamic rather than static. Instead of a single transistor continuously conducting, the system dynamically switches between multiple transistors based on timing control. The control circuit adjusts the operational state of different transistors in real-time, creating a dynamic operation mode that prevents fixed electrical characteristic degradation and maintains display uniformity over time.
2Reliability
If multiple transistors are used in alternating driving mode, then transistor electrical characteristics remain stable, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the driving function into separate segments handled by different transistors. Instead of using one transistor for the entire driving period, the system segments the operation time into distinct periods, with each period handled by a dedicated transistor. This segmentation allows each transistor to have dedicated drive time followed by recovery time, stabilizing electrical characteristics while using a manageable number of transistors (first transistor, second transistor, and control transistor).
Solution Approach 2:
The control transistor serves multiple functions: it controls the switching between the first and second transistors, generates timing signals for alternating operation, and coordinates the overall driver circuit operation. This multi-functionality reduces the need for separate control components, thereby limiting the increase in device complexity while achieving stable transistor characteristics through alternating operation.
Data Source
AI summary
A pixel driver circuit and a display panel are provided. The pixel driver circuit includes a control transistor, a first transistor, a fourth transistor, a light emitting device. A gate electrode of the control transistor receives first control signals, a source electrode of the control transistor receives data signals. A drain electrode of the control transistor is connected to a gate electrode of the first transistor and a gate electrode of the fourth transistor. A source electrode of the first transistor receives first power signals. A source electrode of the fourth transistor receives second power signals. Drain electrodes of the first transistor and fourth transistor are connected to an anode of the light emitting device. The first transistor and fourth transistor correspond to a first driving time period and a second driving time period alternated. The pixel driver circuit and display panel of the present invention enhance display effect.