Active Matrix Substrate Leakage Current Management
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Solution Overview
Problem
Existing electrostatic protection circuits in imaging panels, such as those used in liquid crystal display devices and solid-state image pickup devices, can introduce leakage currents that interfere with image pickup, especially when photoelectric conversion elements are involved, leading to inaccurate image capture and potential damage from static electricity.
Innovation Solution
An active matrix substrate with a configuration that includes data protection circuits connected to data lines via a common line with a potential equal to or lower than the data lines, and bias protection circuits with non-linear elements in reverse bias states to manage and reduce leakage currents, ensuring accurate image pickup without interference from static electricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-linear elements are connected between video signal lines and common lines to protect thin film transistors from static electricity, then reliability is improved, but leakage current enters video signal lines causing measurement precision to deteriorate
Solution Approach 1:
A ground line is introduced as an intermediary component between the data lines and the common line. The ground line serves as a mediator that provides a safe path for leakage current from non-linear elements to flow to ground, preventing the current from entering the data lines and affecting photoelectric conversion elements while still maintaining static electricity protection functionality.
Solution Approach 2:
The electrical connection path is segmented into separate components: data lines, ground line, common line, and non-linear elements. By dividing the circuit into distinct segments with the ground line as a separate intermediate component, the patent isolates the leakage current path from the data lines while maintaining protection functionality.
2Measurement precision
If non-linear elements are connected in reverse bias state to data lines to reduce leakage current, then measurement precision is improved, but static electricity cannot be released when bias line has higher potential causing reliability to deteriorate
Solution Approach 1:
The bias state of non-linear elements is made dynamic rather than fixed. The common line potential is adjusted to be lower than or equal to data line potential, allowing non-linear elements to automatically switch between forward bias and reverse bias states depending on the electrical conditions, thereby providing both leakage current reduction and static electricity protection.
Solution Approach 2:
The patent changes the potential parameter of the common line relative to data lines. By setting the common line potential to be lower than or equal to data line potential, the operating state of non-linear elements changes, enabling them to function effectively in both leakage current reduction and static electricity protection modes.
3Reliability
If common lines are arranged to surround display area with intersections of signal lines, then reliability is improved through electrostatic protection, but device complexity increases due to additional line intersections
Solution Approach 1:
The ground line is extracted as a separate functional component from the common line system. By taking out the grounding function and implementing it through a dedicated ground line connected to non-linear elements, the patent simplifies the overall line configuration while maintaining electrostatic protection reliability.
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 effectively reduces leakage currents and prevents static electricity from affecting image pickup, ensuring accurate and reliable image capture by maintaining the integrity of data and bias lines, thus protecting the photoelectric conversion elements and improving image quality.
Implementation Method 1
the first data non-linear element is connected in a reverse bias state between the first common line and the data line
Data Source
AI summary
Provided is a technique of image pickup without being affected by leakage current on an active matrix substrate that includes photoelectric conversion elements.An active matrix substrate 1 includes photoelectric conversion elements that are respectively provided with respect to a plurality of pixels defined by gate lines and data lines 10, and a bias line 13 supplying a bias voltage to each photoelectric conversion element. Further, the active matrix substrate 1 further includes a plurality of data protection circuit units 16a that are connected with the data lines 10, respectively, and a first common line 17a that is connected with the data protection circuits 16a and has a potential equal to or lower than those of the data lines 10, outside the image pickup area composed of a plurality of pixels. The data protection circuit unit 16a includes a first data non-linear element 161a, and the first data non-linear element 161a is connected in a reverse bias state between the first common line 17a and the data lines 10.