P-Type Shifting Register for Compact OLED Gate Driving

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Solution Overview

Problem

Existing low temperature poly-silicon (LTPS) shifting registers for display panels, particularly those used in organic light emitting diode (OLED) circuits, are complex and occupy large space, making it difficult to narrow the bezel of the display device due to the need for both P-type and N-type transistors for high and low-level pulse signal shifting.

Innovation Solution

A simplified shifting register design using P-type transistors with an input sub-circuit, control sub-circuit, and output sub-circuit, reducing transistor count and optimizing circuit layout by controlling node potentials through clock signals and power terminals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If both P-type and N-type transistors are used for high and low-level pulse signal shifting, then the shifting register can achieve complete pulse signal output, but the circuit complexity increases and the occupied area increases

Engineering Contradiction:

Improvepulse signal output capabilityVSAvoidcircuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The shifting register circuit is divided into three independent sub-circuits: input sub-circuit, control sub-circuit, and output sub-circuit. Each sub-circuit uses only P-type transistors and performs a specific function, eliminating the need for N-type transistors while maintaining complete pulse signal output capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The control sub-circuit is designed to generate both high-level and low-level control signals using only P-type transistors. By using the first clock signal terminal for charging and the second clock signal terminal for discharging, the circuit achieves universal functionality for both signal levels without requiring different transistor types.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If both P-type and N-type transistors are used for high and low-level pulse signal shifting, then the shifting register can achieve complete pulse signal output, but the occupied area increases

Engineering Contradiction:

Improvepulse signal output capabilityVSAvoidcircuit layout area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The circuit is segmented into three functional sub-circuits, each using only P-type transistors. This segmentation allows for optimized layout of each sub-circuit independently, reducing the total occupied area while maintaining the ability to output both high and low-level pulse signals.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The circuit uses dual clock signal terminals with different phases to control the P-type transistors. By changing the timing parameters of the clock signals (first clock for charging, second clock for discharging), the circuit achieves low-level signal output without requiring N-type transistors, thereby reducing the occupied area.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If a simplified shifting register using only P-type transistors is used, then the circuit complexity and occupied area are reduced, but the ability to output both high and low-level signals must be maintained

Engineering Contradiction:

Improvecircuit complexityVSAvoidsignal output capability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The control sub-circuit is designed with dual functionality: it can output high-level signals during the first clock phase and low-level signals during the second clock phase. This multi-functionality is achieved by using complementary clock signals to control the same P-type transistor, ensuring complete signal output capability while maintaining circuit simplicity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The circuit uses periodic clock signals with alternating phases to control the P-type transistors. During the first clock phase, P-type transistors output high-level signals; during the second clock phase, they output low-level signals. This periodic action enables the simplified circuit to maintain full signal output capability.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS12424143B2Shifting register with fewer transistors, driving method, gate driving circuit and display device

Publication Date: 2025.09.23 CHENGDU BOE OPTOELECTRONICS TECH CO LTD

AI summary

The present disclosure relates to the field of display, and discloses a shifting register, a driving method, a gate driving circuit and a display device. The shifting register includes: an input sub-circuit, coupled to a signal input terminal, a first clock signal terminal and a first node; a control sub-circuit, coupled to the first clock signal terminal, a second clock signal terminal, the signal input terminal, a first power terminal, a second power terminal and a second node, where the first power terminal or the second power terminal determines a potential of the second node under the control of the first clock signal terminal, the second clock signal terminal and the signal input terminal; and an output sub-circuit, coupled to the first power terminal, the second power terminal, the first node, the second node and a signal output terminal.