Global Current Sensing Circuit for Display Luminance Compensation
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Solution Overview
Problem
The fluctuation in global current due to changes in electrical characteristics of transistors in a display device leads to reduced luminance over time, affecting the performance of display devices.
Innovation Solution
A global sensing current generating circuit that includes a plurality of sensing current generating circuits, a single current sensing line, and a current summing circuit to sense and compensate for fluctuations in the global current, using driving transistors, capacitors, and switch transistors to sample threshold voltages, and a timing controller to adjust luminance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If transistors are used in pixel circuits for display operation, then the display device can function and provide image output, but the electrical characteristics of transistors change over time causing global current fluctuation and luminance degradation
Solution Approach 1:
The patent implements a feedback mechanism where sensing current generating circuits continuously monitor the global current flowing through the pixel array. The sensed current values are fed back to a timing controller that calculates compensation values and adjusts the image data luminance accordingly. This closed-loop feedback system automatically compensates for transistor characteristic changes over time, maintaining stable luminance despite prolonged operation.
Solution Approach 2:
The patent changes the luminance parameter of the displayed image based on sensed global current values. By dynamically adjusting the luminance parameter in response to detected current fluctuations, the system compensates for transistor degradation effects. The timing controller modifies image data parameters (luminance values) to counteract the natural parameter drift in transistor electrical characteristics over time.
2Measurement precision
If multiple sensing current generating circuits are used to sense global current, then measurement accuracy improves, but circuit complexity increases
Solution Approach 1:
The patent divides the sensing function into multiple independent sensing current generating circuits distributed across different regions of the pixel array. Each sensing circuit independently generates and outputs sensing current based on local transistor characteristics. This segmentation allows parallel measurement of global current from multiple points, improving overall measurement precision while keeping each individual sensing circuit simple and modular.
Solution Approach 2:
The patent merges the outputs of multiple sensing current generating circuits through a current summing line that collects sensing currents from all circuits. By combining multiple sensing signals into a single global current value, the system achieves accurate global current measurement without requiring complex individual circuit designs. The merging process integrates simple sensing units into a powerful collective measurement system.
Data Source
AI summary
A global sensing current generating circuit and a display device including the same, and more particularly to a global sensing current generating circuit that senses a global current in a display area, and a display device that compensates for a fluctuation in the global current based on a current value of the sensed global current.