OLED Pixel Voltage Adjustment for ADC Sensing Range Overflow
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Solution Overview
Problem
Existing external compensation technologies for organic light emitting diode (OLED) displays struggle to accurately sense driving characteristics of pixels when these characteristics exceed the sensing range of an analog-to-digital converter (ADC), leading to inaccurate sensing and compensation.
Innovation Solution
The solution involves a low potential power voltage adjustment unit that reduces the low potential power voltage of pixels to a negative voltage in sensing mode and adjusts it to a ground level voltage in driving mode, allowing an ADC to accurately sense anode voltages of OLEDs by adjusting the voltage within the ADC's sensing range through an offset compensation mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the ADC sensing range is fixed, then the ADC can accurately sense driving characteristics within its designated range, but it cannot accurately sense driving characteristics when they exceed the sensing range due to overflow
Solution Approach 1:
The patent applies dynamics by making the ADC sensing range adjustable rather than fixed. The sensing range is dynamically changed based on the driving characteristics of the OLED pixel, allowing the system to adapt to different voltage levels. This is achieved by modifying the reference voltage or input voltage applied to the ADC, thereby extending the effective sensing range beyond the fixed hardware limitations.
Solution Approach 2:
The patent changes the voltage parameters (reference voltage or input voltage) supplied to the ADC to extend its effective sensing range. By adjusting these voltage parameters, the system can accommodate driving characteristics that exceed the original fixed sensing range while maintaining measurement precision through proper voltage scaling and reference adjustment.
2Device complexity
If the ADC is designed with a fixed sensing range, then the circuit design is simple, but the sensing accuracy deteriorates when driving characteristics change significantly over time and environment
Solution Approach 1:
The system introduces dynamic adjustment capability to maintain sensing reliability under changing conditions. Although the hardware remains relatively simple, the system dynamically adapts the voltage parameters based on detected driving characteristics, ensuring continuous accurate sensing even as OLED characteristics drift over time and with environmental changes.
Solution Approach 2:
The patent implements feedback by continuously monitoring the driving characteristics of the OLED pixel and using this information to adjust the ADC voltage parameters. This closed-loop approach ensures that the sensing system adapts to changing conditions and maintains accuracy without requiring complex predetermined compensation tables or manual calibration.
3Reliability
If external compensation technology is used to sense driving characteristics, then image quality and lifespan can be improved, but the system becomes vulnerable to overflow errors when driving characteristics exceed the ADC's fixed sensing range
Solution Approach 1:
The external compensation system is enhanced with dynamic voltage adjustment capability. Instead of using a fixed sensing range, the system dynamically adjusts the reference voltage or input voltage to match the current driving characteristics of the OLED. This allows the external compensation technology to maintain measurement precision even as driving characteristics change, preventing overflow errors while continuing to improve image quality and lifespan.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables accurate sensing and compensation of driving characteristics even when they exceed the ADC's sensing range, improving the image quality and lifespan of OLED displays by ensuring precise voltage measurement and minimizing internal compensation circuits.
Implementation Method 1
a low potential power voltage adjustment unit configured to reduce a low potential power voltage of the pixels to a negative voltage in the sensing mode and adjust the low potential power voltage to a ground level voltage in the driving mode
Implementation Method 2
a sensing unit configured to sense an anode voltage of the organic light emitting diode using an analog-to-digital converter in the sensing mode
Implementation Method 3
The organic light emitting diode display implements an input image using a phenomenon, in which the OLED emits light when electrons and holes are combined in an organic layer through a current flowing in a fluorescence or phosphorescence organic thin film
Implementation Method 4
The organic light emitting diode display implements an input image using a phenomenon, in which the OLED emits light when electrons and holes are combined in an organic layer through a current flowing in a fluorescence or phosphorescence organic thin film
Implementation Method 5
The organic light emitting diode display implements an input image using a phenomenon, in which the OLED emits light when electrons and holes are combined in an organic layer through a current flowing in a fluorescence or phosphorescence organic thin film
Data Source
AI summary
An organic light emitting diode display and a method for sensing driving characteristics thereof are discussed. The organic light emitting diode display supplies a data voltage of an input image to pixels each including an organic light emitting diode in a driving mode and senses changes in driving characteristics of the pixels in a sensing mode. The organic light emitting diode display in one example includes a low potential power voltage adjustment unit configured to reduce a low potential power voltage of the pixels to a negative voltage in the sensing mode and adjust the low potential power voltage to a ground level voltage in the driving mode, and a sensing unit configured to sense an anode voltage of the organic light emitting diode using an analog-to-digital converter in the sensing mode.