OLED Sensing Circuit for Voltage Offset Compensation
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Solution Overview
Problem
The display quality of OLED display devices is not uniform due to aging thin film transistors and organic light-emitting diodes, which results in voltage offsets that affect image uniformity.
Innovation Solution
A sensing circuit that senses micro currents and voltages using an amplifier, capacitors, switches, correlated double sampling circuits, and analog-to-digital converters to compensate for voltage offsets by employing different methods for current and voltage sensing, supporting noise reduction and leakage current elimination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sensing circuit is used to sense micro current and voltage, then voltage offsets can be compensated, but noise and leakage current affect measurement precision
Solution Approach 1:
The patent applies preliminary action by performing a first sensing operation before the final measurement to capture noise and leakage current characteristics. The CDS circuit uses this preliminary sensed value to compensate and eliminate the effects of noise and leakage current in the second sensing operation, thereby improving measurement precision.
Solution Approach 2:
The patent implements feedback by using the sensed noise and leakage current values to adjust and compensate the measurement process. The CDS circuit feeds back the preliminary sensing results to cancel out the harmful effects during the actual measurement, creating a closed-loop compensation mechanism.
2Illumination intensity
If thin film transistors and OLEDs are used in display device, then display quality can be improved, but aging causes voltage offsets that reduce display uniformity
Solution Approach 1:
The patent uses feedback by sensing the actual voltage offsets in thin film transistors and OLEDs through the sensing circuit, then compensating these offsets to maintain uniform display quality. The controller adjusts drive signals based on sensed characteristics, creating a closed-loop system that counteracts aging effects.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting drive voltages and currents based on sensed characteristics of aging components. The sensing circuit measures actual voltage offsets, and the controller modifies operating parameters to compensate for degradation, maintaining display uniformity despite component aging.
Data Source
AI summary
A sensing circuit for sensing a micro current and voltage of a device to be tested is disclosed. The sensing circuit includes a pixel circuit and a sensing circuit. The sensing circuit is connected to the pixel circuit via a sensing line. The sensing circuit includes an amplifier, a first capacitor, a first switch, a second switch, a third switch, a fourth switch, a correlated double sampling (CDS) circuit, and an analog-to-digital converter (ADC).