Display Device Sensing Circuit Element Degradation
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Solution Overview
Problem
Organic light emitting display devices face degradation issues over time, affecting the intrinsic characteristics of circuit elements such as driving transistors and light emitting diodes, leading to luminance deviations and reduced image quality due to unaddressed intrinsic characteristic value deviations.
Innovation Solution
A display device and method that includes a sensor, timing controller, and data driver to sense characteristic values of circuit elements, calculate compensation data voltages, and adjust initialization and data voltages for each sensing mode, using maximum threshold voltage, mobility, and characteristic value compensation values to maintain stable operation and prevent degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If circuit elements are used in organic light emitting display devices, then the display device can emit light efficiently and achieve fast response speed, but the circuit elements degrade over time causing intrinsic characteristic changes
Solution Approach 1:
The patent applies preliminary action by sensing the characteristic values of circuit elements (such as threshold voltage and mobility of driving transistors) before they cause significant degradation effects. The system performs compensation operations in advance by adjusting initialization voltages and data voltages based on sensed characteristic values, preventing luminance deviations before they occur. This proactive approach maintains display quality while the circuit elements are still within acceptable operational parameters.
Solution Approach 2:
The patent implements feedback mechanisms by continuously sensing the characteristic values of circuit elements in each pixel and using this information to adjust compensation voltages. The sensed characteristic values feed back to the timing controller, which calculates adjusted initialization and data voltages to compensate for element degradation. This closed-loop feedback system dynamically maintains display uniformity despite ongoing circuit element degradation.
2Manufacturing precision
If characteristic values of circuit elements are sensed and compensation voltages are calculated, then luminance uniformity is improved, but the sensing period and processing time increase
Solution Approach 1:
The patent applies partial action by selectively sensing and compensating for the most critical characteristic values of circuit elements. Rather than measuring all possible parameters, the system focuses on key characteristics such as threshold voltage and mobility of driving transistors, and characteristic values of light emitting diodes. This selective approach achieves sufficient luminance uniformity while minimizing the sensing period and processing overhead.
Solution Approach 2:
The patent utilizes parameter changes by adjusting voltage parameters (initialization voltage and data voltage) based on sensed characteristic values. The timing controller modifies these voltage parameters dynamically to compensate for circuit element variations. By changing voltage parameters rather than physical structure or material properties, the system achieves luminance uniformity compensation efficiently within the sensing period.
3Stability of the object's composition
If different initialization voltages are applied for different sensing modes, then pixel operation stability is improved, but the complexity of voltage generation increases
Solution Approach 1:
The patent applies universality by designing a multi-functional voltage generation system that can produce different initialization voltages for different sensing modes using a unified architecture. The data driver is capable of generating initialization voltages adapted to various sensing modes (such as threshold voltage sensing, mobility sensing, and characteristic value sensing) without requiring separate dedicated voltage generators for each mode. This multi-functional approach maintains pixel operation stability across different sensing operations while avoiding the complexity of multiple independent voltage generation circuits.
Data Source
AI summary
A display device includes a sensor, a timing controller, and a data driver. The sensor senses characteristic values of an element included in a pixel of the display device using input initialization and data voltages in a sensing period of one frame period. The timing controller calculates compensation data voltage using the characteristic values, and calculate adjusted initialization and data voltages in the sensing period by using the compensation data voltage. The data driver output the adjusted initialization and data voltages to the pixel during the sensing period in response to a control signal output from the timing controller.