Electro-luminescence Display Kickback Compensation Circuit
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Solution Overview
Problem
Current-driven type electro-luminescence display devices suffer from non-uniform picture quality due to kickback effects caused by parasitic capacitors, leading to inconsistent and uneven image display.
Innovation Solution
Incorporation of a compensation circuit that operates complementary to the drive switches to counteract kickback voltages generated during voltage changes, ensuring uniform current supply to organic light-emitting devices across pixel areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If drive switches are used to control current supply to EL, then pixel switching and current control are enabled, but kickback voltage is generated causing non-uniform picture quality
Solution Approach 1:
A compensation capacitor is introduced as an intermediary element between the drive switch and the EL. This capacitor captures the kickback voltage generated during switch operation, preventing it from directly affecting the EL current. The compensation capacitor acts as a buffer that mediates between the switching action and the light emission, eliminating the non-uniformity caused by kickback effects.
Solution Approach 2:
The harmful kickback voltage is extracted and isolated from the main current path through the compensation capacitor. By separating the kickback effect from the EL driving current, the harmful voltage fluctuation is removed from the critical path, allowing uniform current supply to the EL while maintaining switch control functionality.
2Reliability
If parasitic capacitors are present in the circuit, then circuit functionality is maintained, but kickback effects occur causing DC voltage offset and image non-uniformity
Solution Approach 1:
The compensation capacitor utilizes the inherent parasitic capacitance concept but transforms it into a beneficial element. Instead of allowing parasitic capacitors to generate harmful kickback effects, a dedicated compensation capacitor is used to intentionally store and manage voltage fluctuations, converting the potentially harmful capacitive effect into a useful compensation mechanism that improves image uniformity.
Data Source
AI summary
An electro-luminescence display device includes a plurality of column lines, a plurality of first row lines and a plurality of second row lines. The plurality of first row lines cross the column lines and a first scan signal is supplied thereto. The plurality of second row lines intersects the column lines and a second scan signal is supplied thereto. Organic light emitting devices are formed at pixel areas which are defined by the column lines and the first and second row lines. At least two drive switches operate to drive the organic light emitting devices. The second scan signal applies later than the first scan signal to activate the drive switches. A kickback voltage is generated upon a voltage change of the first row line. A kickback compensation circuit operates to cancel the kickback voltage.