OLED Display Data Line Sensing for Deterioration Compensation
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Solution Overview
Problem
Organic light-emitting displays face issues with OLED deterioration leading to brightness variations and image sticking due to differences in accumulated light-emitting time across pixels, which existing technologies attempt to address through deterioration compensation but are limited by the need for reference lines that reduce wiring design margin and prevent individual pixel sensing.
Innovation Solution
An organic light-emitting display design that eliminates reference lines by using data lines to sense OLED operating point voltage, incorporating digital-to-analog converters, sensing units, and connecting switches to generate and apply sensing voltages, allowing for direct or indirect sensing of OLED deterioration through data lines, thereby improving wiring design margin and aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference lines are added to sense OLED operating point voltage, then OLED deterioration sensing capability is improved, but wiring design margin is reduced
Solution Approach 1:
The data line is designed to serve dual purposes: transmitting image data during normal operation and sensing OLED operating point voltage during sensing periods. This eliminates the need for separate reference lines while maintaining individual pixel sensing capability, thereby improving wiring design margin without sacrificing measurement precision
Solution Approach 2:
The sensing function previously requiring separate reference lines is merged into the existing data line infrastructure. By combining data transmission and voltage sensing functions into a single line, the patent reduces the total wiring area while preserving the ability to sense each pixel's OLED deterioration individually
2Device complexity
If multiple neighboring pixels share a single reference line, then the number of reference lines is reduced, but individual pixel sensing capability is lost
Solution Approach 1:
The data line's function dynamically switches between data transmission and voltage sensing modes through control signals. During sensing periods, the data line temporarily serves as a sensing line for individual pixels, while during normal operation it transmits image data. This dynamic switching enables individual pixel sensing without requiring separate dedicated sensing lines for each pixel
Solution Approach 2:
The system employs periodic sensing operations where the data line alternates between data transmission mode and voltage sensing mode. Control signals periodically switch the data line's function, allowing individual pixel OLED deterioration to be sensed at specific time intervals without interfering with normal display operations, thus maintaining individual pixel sensing capability while sharing the same physical line infrastructure
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 easier wiring design margin in the display panel by eliminating reference lines and effectively sensing OLED deterioration, reducing brightness variations and improving image quality by accurately compensating for pixel differences in OLED performance.
Implementation Method 1
An OLED, which is a self-luminous device, typically includes an anode, a cathode, and organic compound layers formed between the anode and cathode. When a power supply voltage is applied to the anode and the cathode, a hole passing through the hole transport layer HTL and an electron passing through the electron transport layer ETL move to the emission layer EML, forming an exciton. As a result, the emission layer EML generates visible light.
Data Source
AI summary
An organic light-emitting display organic light-emitting display includes a display panel having a plurality of pixels, a plurality of data lines that are connected to the pixels, and a plurality of gate lines that are connected to the pixels; and a data drive circuit having a plurality of digital-to-analog converters configured to generate an image data voltage and a sensing data voltage to be applied to the pixels, a plurality of sensing units configured to sense an organic light-emitting diode (OLED) operating point voltage of the pixels, and a plurality of connecting switches configured to selectively connect the digital-to-analog converters and the sensing units to the data lines.