Electrooptical Device Capacitive Coupling Signal Stability
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Solution Overview
Problem
Existing electrooptical devices face issues with consistency in uniformity due to variations in capacitance values, affecting the specification of video signal voltage.
Innovation Solution
The electrooptical device incorporates a scanning line, signal line, feed line, pixel circuit, drive circuit, level shift block, first capacitor, and second capacitor formed by parasitic capacitance, where the signal line and feed line are made of equal-width metal layers, allowing capacitive coupling to stabilize video signal voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two capacitances are used to specify video signal voltage in the pixel circuit, then the video signal can be written into the signal line, but variations in capacitance values cause variations in video signal voltage, impairing consistency of uniformity
Solution Approach 1:
The patent merges the first capacitor and second capacitor into a single capacitive coupling structure formed by the signal line and feed line. This integration ensures that both capacitances are determined by the same geometric parameters (width, length, spacing), making their ratio constant and eliminating video signal voltage variations caused by capacitance value fluctuations.
Solution Approach 2:
The patent changes the parameter specification approach from absolute capacitance values to a ratio-based parameter. By expressing the video signal voltage in terms of the capacitance ratio (C1/C2) rather than individual capacitance values, the system becomes insensitive to variations in absolute capacitance, thereby maintaining consistency of uniformity.
2Manufacturing precision
If the first metal layer and second metal layer are formed with equal width, then the first capacitor and second capacitor are formed with consistent geometry, but this requires precise manufacturing control
Solution Approach 1:
The signal line and feed line serve dual functions: they act as signal transmission conductors and simultaneously form the capacitor structures. By making both lines the same width, the design achieves uniformity in capacitance formation without requiring separate capacitor fabrication processes, simplifying manufacturing while maintaining precision.
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 configuration reduces capacitance variations, ensuring consistent uniformity and stability of video signal voltage, thereby preventing impairment of image consistency.
Implementation Method 1
a video signal voltage is written into the pixel circuit by capacitive coupling between the first capacitor and the second capacitor
Implementation Method 2
a second capacitor formed by a parasitic capacitance between the signal line and the feed line
Data Source
AI summary
An electrooptical device and apparatus are disclosed. In one example, an electrooptical device includes a scanning line, a signal line, a feed line to which a low potential is supplied, a pixel circuit, a drive circuit for driving the pixel circuit, a level shift block connected to the signal line, a first capacitor on the level shift block, and a second capacitor formed by a parasitic capacitance between the signal line and the feed line. A video signal voltage is written into the pixel circuit by capacitive coupling between the first capacitor and the second capacitor. The signal line is formed of a first metal layer. The feed line is formed of a second metal layer that is approximately equal in width to the first metal layer. The first metal layer and the second metal layer form the first capacitor and the second capacitor.