Comb-Electrode Shift Register Layout to Prevent Channel Short Circuits

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Solution Overview

Problem

In display technology, the integration of gate driving circuits on array substrates faces challenges with channel short circuits in shift registers, particularly in ultra-narrow frame displays, where transistors of different sizes lead to irregular transition regions and photoresist accumulation, causing defects like horizontal striations during display.

Innovation Solution

The design of a shift register with comb-shaped electrodes and handle portions forms a short circuit prevention region on the active layer, preventing photoresist accumulation and channel short circuits by defining distinct gaps and projections that allow normal signal output and avoid defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If transistors of different sizes are used in the shift register to achieve ultra-narrow frame displays, then the frame width is reduced, but channel short circuits occur due to irregular transition regions and photoresist accumulation

Engineering Contradiction:

Improveframe widthVSAvoidchannel short circuit

Core Design Contradiction:

Length of stationary objectVSReliability

Solution Approach 1:

The electrode structure is segmented into multiple comb tooth portions (first, second, third, fourth comb tooth portions) with different lengths, arranged in an inter-digital configuration. This segmentation allows precise control of the active layer coverage and creates distinct gaps that prevent photoresist accumulation while maintaining the ultra-narrow frame design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the electrode structure have different local qualities - the first and second comb tooth portions have different lengths from the third and fourth comb tooth portions. This creates localized variations in the active layer coverage and gap sizes, specifically designing the gaps to be larger in certain regions to prevent photoresist accumulation and channel short circuits.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If comb-shaped electrodes with different lengths are used to form inter-digital structures, then the active layer coverage is improved, but photoresist accumulation occurs in transition regions

Engineering Contradiction:

Improveactive layer coverageVSAvoidphotoresist accumulation

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The electrode structure is designed with predetermined gap sizes and configurations before fabrication. The gaps between adjacent comb tooth portions are engineered to be sufficiently large to prevent photoresist accumulation during the photolithography process, eliminating the need for additional corrective actions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The different lengths of comb tooth portions create irregular transition regions that would normally be problematic, but these same irregularities are designed to form larger gaps that actively prevent photoresist accumulation. The potential harm of irregular transitions is converted into a beneficial feature that improves manufacturing precision.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If the gaps between comb tooth portions are made larger to prevent photoresist accumulation, then channel short circuits are prevented, but the electrode structure becomes more complex

Engineering Contradiction:

Improveshort circuit preventionVSAvoidelectrode structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Multiple functional requirements are merged into a single electrode structure design. The inter-digital arrangement of comb tooth portions simultaneously achieves active layer coverage, gap formation for short circuit prevention, and photoresist accumulation avoidance. The handle portions connect all comb tooth portions into unified first and second electrodes, integrating multiple functions without proportionally increasing complexity.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11862061B2Shift register, gate driving circuit and display panel

Publication Date: 2024.01.02 BEIJING BOE DISPLAY TECH CO LTD

AI summary

The present disclosure provides a shift register, a gate driving circuit and a display panel. The shift register includes a transistor, which includes a gate electrode, a gate insulating layer, an active layer, a first electrode and a second electrode; the first and second electrode are of comb-shaped structures; the first electrode includes first and second comb tooth portions arranged at intervals, and a first comb handle portion connecting the first and second comb tooth portions; and comb tooth electrodes of the first comb tooth portions have a different length from those of the second comb tooth portions; the second electrode includes third and fourth comb tooth portions arranged at intervals, and a second comb handle portion connecting the third and fourth comb tooth portions; the first and third comb tooth portions form an inter-digital structure, the second and fourth comb tooth portions form an inter-digital structure.