Pixel Circuit with Split Initialization Voltages for Color Stability
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Solution Overview
Problem
Display devices experience color deviation due to temperature sensitivity of light emitting elements, which affects display quality.
Innovation Solution
A pixel structure with separate initialization power voltages for threshold voltage compensation and temperature sensitivity compensation of the driving transistor and light emitting element, respectively, allowing independent control of these processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single initialization power voltage is used for both threshold voltage compensation and temperature sensitivity compensation, then the pixel circuit structure is simple, but color deviation occurs due to inability to independently control compensation processes
Solution Approach 1:
The patent divides the initialization power voltage into two separate voltages: a first initialization power voltage for threshold voltage compensation of the driving transistor, and a second initialization power voltage for temperature sensitivity compensation of the light emitting element. This segmentation allows independent control of each compensation process, preventing color deviation while maintaining manageable circuit complexity through dedicated compensation paths.
Solution Approach 2:
The patent applies different initialization power voltages to different components at different locations in the compensation process. The first initialization power voltage is applied to the driving transistor for threshold voltage compensation, while the second initialization power voltage is applied to the light emitting element for temperature sensitivity compensation. This local differentiation ensures each component receives the specific compensation it needs without interference.
2Manufacturing precision
If threshold voltage compensation is performed without separate temperature sensitivity compensation, then the compensation process is simple, but temperature sensitivity of light emitting element causes color deviation
Solution Approach 1:
The patent performs temperature sensitivity compensation as a preliminary action before the main light emission process. By applying the second initialization power voltage to initialize the light emitting element's anode to a specific voltage level (lower than the threshold voltage) before data writing, the temperature sensitivity effect is pre-compensated. This preliminary compensation ensures accurate threshold voltage compensation without being affected by temperature-induced impedance changes.
3Object-affected harmful factors
If the light emitting element anode is initialized to a high voltage level, then temperature sensitivity is reduced, but the driving transistor threshold voltage compensation is affected
Solution Approach 1:
The patent segments the initialization process into two distinct stages with separate power voltages. First, the driving transistor receives the first initialization power voltage for threshold voltage compensation. Second, the light emitting element receives the second initialization power voltage (higher than the first) for temperature sensitivity compensation. This segmentation allows the anode to be initialized to a high voltage level for temperature compensation without affecting the previously completed threshold voltage compensation of the driving transistor.
Data Source
AI summary
A pixel includes a driving transistor having a gate electrode connected to a first node and connected between a first power line to which a first power voltage is applied and a second node, a first initialization transistor having a gate electrode connected to a first scan line and connected between the second node and a first initialization power line to which a first initialization power voltage is applied, a second initialization transistor having a gate electrode connected to the first scan line and connected between a third node and a second initialization power line to which a second initialization power voltage is applied, a first capacitor connected between the first node and the second node, a second capacitor connected between the first power line and the second node, and a light emitting element connected between the third node and a second power line.