Active Matrix Display Driving Circuit Alternating Scan Order
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Solution Overview
Problem
Active matrix display devices with reduced source lines suffer from display unevenness due to inter-pixel parasitic capacitance, which causes electrical potential variations and visible defects like bright and dark stripes.
Innovation Solution
A driving circuit and method that alternates the selection order of scanning lines for pairs of adjacent pixels connected to different signal lines in each field, ensuring that the writing order of video signals is reversed between fields to average potential differences and reduce display unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If one source line is shared by two adjacent pixels to reduce the number of source lines, then the routing area of wiring lines is reduced and the picture frame is narrowed, but inter-pixel parasitic capacitance increases causing display unevenness
Solution Approach 1:
The patent applies periodic action by alternating the writing order of video signals to adjacent pixels between fields. In the first field, the left pixel is written before the right pixel, while in the second field, the writing order is reversed. This periodic alternation averages out the electrical potential variations caused by inter-pixel parasitic capacitance over time, eliminating display unevenness while maintaining the shared source line configuration that reduces routing area.
2Area of stationary object
If the number of source lines is reduced to half, then the area occupied by source lines is reduced and the picture frame is narrowed, but electrical potential variations occur due to inter-pixel parasitic capacitance
Solution Approach 1:
The patent converts the harmful electrical potential variations caused by inter-pixel parasitic capacitance into a beneficial effect by utilizing the alternating writing order between fields. The potential variations that would normally cause display unevenness are instead averaged out over multiple fields, transforming the harmful capacitance effect into a mechanism that actually equalizes potential differences and improves display uniformity.
3Ease of manufacture
If video signals are written to pixels in a fixed order, then the writing process is simple, but visible display defects like bright and dark stripes occur
Solution Approach 1:
The patent introduces dynamics to the writing process by making the writing order variable rather than fixed. The writing sequence alternates between fields: in the first field, pixels are written from left to right, while in the second field, the order is reversed from right to left. This dynamic adjustment of writing order prevents the formation of fixed patterns in display defects, eliminating visible bright and dark stripes while maintaining process simplicity through automated field-based control.
Data Source
AI summary
In an active matrix display device, one source line is arranged for every two pixels arranged along a gate line direction, and each two pixels which are adjacent to each other along the gate line direction across one of the source lines share the source line and are each connected to different gate lines. A gate driver block performs a first driving control which sequentially selects, in a first order, the gate lines in a pair of two gate lines corresponding to two pixels which are adjacent to each other along the gate line direction and are connected to different source lines. The gate driver block also performs a second driving control which sequentially selects, in a second order which is opposite to the first order, the gate lines in such a pair of two gate lines.