Pixel Sensing Circuit for OLED Luminance Compensation
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Solution Overview
Problem
Existing electroluminescence display apparatuses face limitations in implementing images due to luminance deviations caused by differences in driving characteristics between pixels, which current compensation technologies struggle to address effectively.
Innovation Solution
An electroluminescence display apparatus is designed with an enhanced sensing circuit that supplies a pixel reference voltage and senses a pixel current through a reference voltage line, utilizing a sensing channel terminal, switches, an integrator amplifier, capacitors, and a current integrator to improve sensing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage initialization is performed before sensing, then sensing accuracy is improved, but display operation is interrupted and sensing time is reduced
Solution Approach 1:
The sensing circuit performs voltage initialization in advance during the display driving operation, so that when the sensing operation begins, the initialization is already complete. This eliminates the need to interrupt display for initialization and allows full use of the vertical blank period for sensing.
Solution Approach 2:
The display and sensing operations are made continuous by performing voltage initialization during the display driving operation rather than interrupting it. The sensing circuit maintains continuous operation across both display and sensing phases, maximizing utilization of available time.
2Speed
If sensing operation is performed during vertical blank period, then sensing speed is improved, but sensing time is limited
Solution Approach 1:
Voltage initialization is performed in advance during the display driving operation, before the sensing operation begins. This ensures that when sensing starts in the vertical blank period, no additional initialization time is needed, maximizing the available sensing time within the limited vertical blank period.
3Reliability
If compensation technology is applied, then luminance deviation is reduced, but compensation performance is limited due to low sensing performance
Solution Approach 1:
The patent replaces conventional sensing methods with a capacitor-based integration sensing circuit. The capacitor integrates the pixel current over time, and the integrator amplifier converts this integrated charge to a voltage signal, providing high-precision sensing that overcomes the limitations of previous compensation technologies.
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
The proposed solution significantly enhances sensing performance by allowing continuous display and sensing operations without the need for voltage initialization, thereby securing sufficient current sensing time within a limited vertical blank period.
Implementation Method 1
a first capacitor connected between the sensing channel terminal and the first input terminal
Implementation Method 2
an integrator amplifier including a first input terminal, a second input terminal, and an output terminal
Data Source
AI summary
An electroluminescence display apparatus includes a pixel and a sensing circuit supplying a pixel reference voltage to the pixel through a reference voltage line during display driving and sensing a pixel current, flowing in the pixel, through the reference voltage line during sensing driving succeeding the display driving operation. The sensing circuit includes a sensing channel terminal connected to the reference voltage line, a first switch between the sensing channel terminal and an input terminal for the pixel reference voltage, an integrator amplifier including a first input terminal, a second input terminal, and an output terminal, an input terminal for an integrator reference voltage connected to the second input terminal, a second switch between the first input terminal and the output terminal, a first capacitor between the sensing channel terminal and the first input terminal, and a second capacitor between the sensing channel terminal and the output terminal.