Touch Display Panel Drive Circuit Leakage Current Control

Solution Overview

Problem

Capacitive touch panels with In-Cell technology face issues of leakage current leading to error readings and increased power consumption, resulting in decreased screen brightness and unstable display images due to noise signals from adjacent rows.

Innovation Solution

A touch display panel drive circuit with a data line switch and voltage comparator that disconnects the pixel electrode from the data line drive unit when no signal is output, preventing leakage current noise and reducing power consumption by forming a high-impedance state, and conducts when a signal is output to form a path for data transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the transistor continuously connects the data line to the pixel electrode for scanning and reading touch signals, then the touch signal reading function is achieved, but leakage current generates noise signals that cause error readings and increase power consumption

Engineering Contradiction:

Improvetouch signal reading accuracyVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The data line switch is turned off in advance during periods when no data signal is being transmitted (e.g., during touch signal reading phase or between frames). This preliminary action prevents leakage current from flowing through the data line to the pixel electrode, thereby eliminating noise signals and reducing power consumption before the harmful effect can occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The data line switch dynamically changes its conduction state based on the operational phase of the display driver circuit. It is turned on only during the specific time window when data signals need to be written to the pixel electrodes, and turned off during other phases such as touch signal reading or idle periods. This dynamic control optimizes the balance between data transmission functionality and power consumption/reliability.

Inventive Principle:

Principle #15Dynamics

2Productivity

If the transistor maintains continuous connection for data signal transmission, then the display update function is achieved, but leakage current causes unstable display images and decreased screen brightness

Engineering Contradiction:

Improvedisplay update efficiencyVSAvoidscreen brightness

Core Design Contradiction:

ProductivityVSIllumination intensity

Solution Approach 1:

The data line switch is turned off in advance during periods when no data signal is being transmitted (e.g., during touch signal reading phase or between frames). This preliminary action prevents leakage current from flowing through the data line to the pixel electrode, thereby eliminating noise signals and reducing power consumption before the harmful effect can occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The data line switch dynamically changes its conduction state based on the operational phase of the display driver circuit. It is turned on only during the specific time window when data signals need to be written to the pixel electrodes, and turned off during other phases such as touch signal reading or idle periods. This dynamic control optimizes the balance between data transmission functionality and power consumption/reliability.

Inventive Principle:

Principle #15Dynamics

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 solution effectively prevents error readings and reduces power consumption, enhancing display brightness and stability, thereby improving the overall display effect of the touch display panel.

Implementation Method 1

The data line switch comprises a voltage comparator, and a non-inverting input end of the voltage comparator is electrically coupled to the data line drive unit, and the inverting input end of the voltage comparator is grounded, and an output end of the voltage comparator is electrically coupled to the pixel switch through the data line

Methodology Applied

Scientific EffectVoltage comparison:

Data Source

PatentUS10222907B2Touch display panel and drive circuit, electronic apparatus thereof

Publication Date: 2019.03.05 WUHAN CHINA STAR OPTOELECTRONICS TECH CO LTD

AI summary

The touch display panel drive circuit provided by the present invention comprises a data line drive unit, a plurality of gate lines and a plurality of data lines, and a junction of two adjacent gate lines and two adjacent data lines forms a pixel region, and a pixel switch is located inside the pixel region; the touch display panel drive circuit further comprises a data line switch between the data line and the data line drive unit; as the data line drive unit does not output the data signal, an output of the data line switch is a high-impedance state, and the data line drive unit is disconnected with the pixel switch. The present invention can prevent the error reading phenomenon generated by the transistor leakage, and can enhance the display brightness and the stability of the display image, and promote the display effect of the touch display panel.