Display Power Voltage Feedback to Prevent Afterimages and Line Defects
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Solution Overview
Problem
Existing display apparatuses suffer from visibility issues such as afterimages, bright lines, and dark lines due to changes in power voltage caused by coupling with data voltage, leading to malfunction of driving transistors.
Innovation Solution
A power voltage generator that calculates a compensated power voltage by inversely amplifying the difference between an initial and sensed power voltage, maintaining a constant voltage output to reduce the impact of coupling effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional power voltage generator is used, then the circuit structure is simple, but power voltage changes due to coupling with data voltage causing afterimages, bright lines, and dark lines
Solution Approach 1:
The power voltage generator senses the actual power voltage at its output terminal and feeds it back to a voltage calculator. The voltage calculator compares the sensed power voltage with a reference voltage and generates a compensation voltage based on the difference. This compensation voltage is then added to the initial power voltage to produce a compensated power voltage that counteracts coupling effects, thereby eliminating afterimages, bright lines, and dark lines while maintaining circuit feasibility.
2Reliability
If power voltage is not compensated, then the device complexity is low, but pixel stability and reliability deteriorate due to voltage fluctuations
Solution Approach 1:
The power voltage generator senses the actual power voltage at its output terminal and feeds it back to a voltage calculator. The voltage calculator compares the sensed power voltage with a reference voltage and generates a compensation voltage based on the difference. This compensation voltage is then added to the initial power voltage to produce a compensated power voltage that counteracts coupling effects, thereby eliminating afterimages, bright lines, and dark lines while maintaining circuit feasibility.
3Object-affected harmful factors
If coupling effects are not addressed, then the power voltage generator is simple, but afterimages, bright lines, and dark lines appear on the display panel
Solution Approach 1:
The power voltage generator senses the actual power voltage at its output terminal and feeds it back to a voltage calculator. The voltage calculator compares the sensed power voltage with a reference voltage and generates a compensation voltage based on the difference. This compensation voltage is then added to the initial power voltage to produce a compensated power voltage that counteracts coupling effects, thereby eliminating afterimages, bright lines, and dark lines while maintaining circuit feasibility.
Solution Approach 2:
The invention utilizes the coupling effect itself to generate the compensation voltage. The voltage calculator receives the sensed power voltage that contains coupling information and processes it to create a compensation voltage that directly counteracts the coupling effect. By converting the harmful coupling effect into useful compensation information, the system eliminates display defects without requiring complex external compensation circuits.
Data Source
AI summary
A display apparatus is disclosed that includes a display panel including a pixel, a gate driver applying a gate signal, a data driver applying a data voltage, an emission driver applying an emission signal and a power voltage generator receiving a sensed power voltage and outputting a compensated power voltage. The pixel includes a driving transistor including a first control electrode receiving the data voltage, a second control electrode connected to a hold capacitor, a first electrode receiving a first power voltage and a second electrode connected to a first electrode of a light emitting element, the hold capacitor including a first electrode receiving the first power voltage and a second electrode connected to the second control electrode of the driving transistor and the light emitting element including a first electrode receiving the first power voltage and a second electrode receiving a second power voltage.