Display Panel Pseudo-Diode Test Pixel for Transistor Degradation
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Solution Overview
Problem
Existing display panels face challenges in accurately measuring transistor degradation due to variations among individual panels, which can lead to inconsistent image quality.
Innovation Solution
Incorporation of a test pixel and pseudo-diode structure in the display panel, allowing for precise measurement of transistor degradation by matching the V-I curves of the pseudo-diode and light-emitting diode, connected through specific connection lines to a measurement circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If degradation curves of transistors are measured by selecting a representative display panel and uniformly applied to all display panels, then measurement complexity is reduced, but measurement precision deteriorates due to panel variations
Solution Approach 1:
The patent creates a pseudo-diode that copies the electrical characteristics of the light-emitting diode without light emission functionality. This copy structure allows separate measurement of transistor degradation without the complexity of measuring actual display performance, resolving the contradiction between measurement simplicity and precision.
Solution Approach 2:
The patent segments the measurement function by separating the light-emitting diode (for display) from the pseudo-diode (for measurement). This segmentation allows independent measurement of transistor degradation through the pseudo-diode, eliminating the need for complex representative panel selection while maintaining measurement precision for each individual panel.
2Measurement precision
If a test pixel and pseudo-diode structure is added to measure transistor degradation accurately, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent merges the measurement function into the existing pixel structure by integrating the pseudo-diode with the light-emitting diode's support structures (electrodes, emission layer). This merging allows accurate degradation measurement without adding separate complex measurement devices, as the pseudo-diode shares infrastructure with the functional light-emitting diode.
Solution Approach 2:
The pseudo-diode structure serves multiple functions: it acts as both a measurement element for transistor degradation and utilizes existing pixel circuitry (electrodes, emission layer, transistors). This multi-functionality reduces overall device complexity while maintaining measurement precision, as the same structural elements serve both display and measurement purposes.
3Measurement precision
If individual panel measurement is implemented for each display panel, then measurement precision improves, but loss of time increases due to separate measurements
Solution Approach 1:
The pseudo-diode enables each panel to self-measure its own transistor degradation through its integrated structure. This self-service capability eliminates the need for time-consuming representative panel selection and uniform application procedures, as each panel independently provides accurate degradation data through its own pseudo-diode measurement.
Data Source
AI summary
A display panel includes a substrate including a display area, and a peripheral area surrounding the display area in plan view, a pixel circuit in the display area, a light-emitting diode in the display area, electrically connected to the pixel circuit, and including a pixel electrode, an opposite electrode, and an emission layer between the pixel electrode and the opposite electrode, a test circuit in the peripheral area, and a pseudo-diode in the peripheral area, electrically connected to the test circuit, and including a first transistor.