Display Module Reset Circuit for Low-Frequency Flicker Control

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Solution Overview

Problem

When a display panel is driven at a low frequency, the threshold voltage shift of the driving transistor causes a change in current flowing through the light-emitting device, exacerbating flicker issues due to long-term bias action.

Innovation Solution

A display module with a reset module that applies bias signals to first transistors through second transistors during a blanking interval, ensuring all first transistors are turned on simultaneously to compensate for threshold voltage shifts and reduce flicker.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the display panel is driven at a low frequency, then power consumption is reduced, but the threshold voltage shift of the first transistor causes current change and aggravates flicker

Engineering Contradiction:
Improvepower consumptionVSAvoidflicker stability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent applies preliminary action by resetting the threshold voltage of the first transistor during the blanking interval before the next frame is displayed. The reset module detects threshold voltage shift and applies a reset signal to restore the transistor's threshold voltage to its initial value, preventing current variation and flicker before they occur during low-frequency operation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using the reset module to continuously monitor the threshold voltage of the first transistor and dynamically adjust the reset signal accordingly. The reset module detects the threshold voltage shift and applies corrective reset signals to maintain stable current flow through the light-emitting device, creating a closed-loop control system that eliminates flicker while preserving low-power operation

Inventive Principle:
Principle #23Feedback

2Duration of action of moving object

If the first transistor is subjected to long-term bias action, then the display can maintain low-frequency operation, but threshold voltage shift occurs causing current instability

Engineering Contradiction:
Improvelow-frequency operation durationVSAvoidcurrent stability
Core Design Contradiction:
Duration of action of moving objectVSManufacturing precision

Solution Approach 1:

The reset module performs preliminary action by resetting the first transistor's threshold voltage during the blanking interval before the transistor is subjected to bias action in the next frame. This preventive reset eliminates accumulated threshold voltage shift from long-term bias operation, maintaining current stability over extended low-frequency operation periods

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies periodic action by resetting the threshold voltage at regular intervals during each blanking interval. The reset module periodically restores the first transistor's threshold voltage to its initial value, preventing cumulative drift that would otherwise occur during prolonged low-frequency operation, thereby maintaining current stability

Inventive Principle:
Principle #19Periodic action

Data Source

PatentUS20230397459A1Display module and display device
Publication Date: 2023.12.07 WUHAN CHINA STAR OPTOELECTRONICS SEMICONDUCTOR DISPLAY TECHNOLOGY CO LTD
  • US20230397459A1 patent drawing
  • US20230397459A1 patent drawing
  • US20230397459A1 patent drawing

AI summary

A display module and a display device are provided. A plurality of first scanning lines are electrically connected to a plurality of first gate driving circuits, a plurality of pixel driving circuits, and a reset module. The reset module outputs a first reset signal within a blanking interval, so that the plurality of bias signals transmitted by the plurality of data lines are applied to the plurality of first transistors through the second transistors in the plurality of pixel driving circuits. Therefore, the plurality of first transistors are turned on in the blanking interval at the same time to improve a flicker problem when the display module is driven at a low-frequency.