Conductive Polarizer for Display Howling Elimination
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Solution Overview
Problem
The display screen industry faces a significant issue known as 'howling,' where users hear a babble sound when close to the screen due to a reverse piezoelectric effect caused by the touch IC sending alternating scan pulse signals, leading to mechanical vibration of the backlight film in the capacitor formed by the touch function layer and backlight metal frame.
Innovation Solution
Incorporating a first polarizer with conductive particles coated or embedded in the adhesive layer, electrically connected to the backlight metal frame, which reduces or eliminates the capacitance between the touch function layer and the backlight metal frame, thereby minimizing the reverse piezoelectric effect and mechanical vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a touch IC sends out alternating scan pulse signals to enable touch operation, then touch functionality is achieved, but the backlight film experiences mechanical vibration due to reverse piezoelectric action causing howling
Solution Approach 1:
The patent introduces a conductive layer formed by conductive particles in the first polarizer as an intermediary element. This conductive layer acts as a shield between the touch function layer and the backlight metal frame, providing an alternative electrical pathway that prevents the formation of the harmful capacitor and eliminates the reverse piezoelectric effect, thereby stopping the howling sound while preserving touch functionality.
Solution Approach 2:
The patent converts the harmful capacitance formed by the touch function layer and backlight metal frame into a beneficial configuration. By introducing the conductive particles in the first polarizer, the patent creates a controlled conductive pathway that deliberately establishes a different capacitor configuration, transforming the harmful electrical interaction into a beneficial shielding effect that eliminates vibration and sound.
2Object-generated harmful factors
If conductive particles are added to the first polarizer to reduce capacitance, then the reverse piezoelectric effect is minimized, but the device structure becomes more complex
Solution Approach 1:
The patent merges the conductive particle function directly into the first polarizer structure. Instead of adding a separate conductive layer or component, the conductive particles are integrated within the adhesive layer of the first polarizer, combining the polarizing function with the conductive shielding function in a single component, thereby reducing overall device complexity.
Solution Approach 2:
The first polarizer is given multiple functions: it provides optical polarization functionality plus incorporates conductive particles that provide electrical shielding and capacitance reduction. This multi-functionality approach allows a single component to address both optical and electrical issues, avoiding the need for additional separate components and reducing device complexity.
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 reduces or eliminates the howling phenomenon by forming a conductive film layer that stabilizes potentials and shields or disperses capacitance, improving user experience by minimizing unwanted noise.
Implementation Method 1
A capacitance formed by the backlight metal frame and the touch function layer can be reduced or eliminated
Implementation Method 2
the conductive particles are electrically connected with the backlight metal frame
Implementation Method 3
a film in the backlight module is constantly mechanically vibrated by a reverse piezoelectric action
Data Source
AI summary
A display device and an electronic device are provided. The display device has an array substrate, a touch function layer, a backlight module, and a first polarizer. By coating and/or embedding conductive particles on the first adhesive layer, a conductive film layer that is electrically connected to a backlight metal frame can be formed between a backlight film and the touch function layer. A capacitance formed by the backlight metal frame and the touch function layer can be reduced or eliminated, so as to reduce or avoid mechanical vibration of the film.