Display Panel Permittivity Reduction for Greenish Effect Prevention
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Solution Overview
Problem
Display panels experience a Greenish phenomenon due to the shift in threshold voltage of driving thin film transistors caused by electric charge accumulation, leading to deteriorated image quality, especially at the edges where it's challenging to apply conductive solutions.
Innovation Solution
Applying permittivity reduction processing to the cover window, adhesive layer, and polarizer in a display panel to form a low-intensity electric field, reducing the penetration and accumulation of electric charges and preventing the shift phenomenon, thereby eliminating the Greenish effect without the need for antistatic solutions or heat dissipation sheets at the pad edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a cover window is added to protect the display panel from external shocks, then the protection capability is improved, but electric charge accumulation occurs in the cover window causing the shift phenomenon and Greenish effect
Solution Approach 1:
A low permittivity adhesive layer is introduced as an intermediary between the cover window and the polarizer. This adhesive layer has a permittivity of 2.6 or less, which is lower than the permittivity of the cover window, thereby reducing the electric field intensity and preventing electric charge accumulation that would otherwise cause the shift phenomenon and Greenish effect.
Solution Approach 2:
The permittivity parameter of the adhesive layer is specifically controlled to be 2.6 or less. By changing this physical parameter (permittivity) of the adhesive layer, the electric field intensity is reduced, which prevents the formation of strong electric fields that would cause threshold voltage shifts in the transistors.
2Reliability
If conductive solutions are applied to prevent electric charge accumulation, then the shift phenomenon is prevented, but the manufacturing complexity increases especially at pad edges
Solution Approach 1:
The patent extracts and removes the heat dissipation sheet from the structure, particularly from the peripheral area where pads are not located. By eliminating this component, the manufacturing process is simplified and the structure is reduced, while the low permittivity adhesive layer continues to provide protection against electric charge accumulation.
Solution Approach 2:
The heat dissipation sheet is discarded (removed) from the peripheral area where it is not needed. The functional requirement for preventing electric charge accumulation is maintained through the low permittivity adhesive layer, making the removal of the heat dissipation sheet acceptable and beneficial for simplification.
3Reliability
If heat dissipation sheets are used to manage electric charge, then the shift phenomenon is prevented, but the display panel thickness and cost increase
Solution Approach 1:
The heat dissipation sheet is extracted (removed) from the display panel structure, particularly from the peripheral area. This removal reduces the overall thickness of the display panel while the low permittivity adhesive layer continues to provide the necessary protection against electric charge accumulation and the shift phenomenon.
Solution Approach 2:
The heat dissipation sheet is discarded as an unnecessary component when the low permittivity adhesive layer is present. The protective function against electric charge accumulation is recovered and maintained through the adhesive layer's low permittivity property, eliminating the need for additional thickness from heat dissipation sheets.
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
Prevents the Greenish phenomenon by reducing the electric field intensity within the panel, improving image quality and allowing for easier manufacturing by omitting heat dissipation sheets, reducing costs and thickness, and enhancing the display panel's reliability.
Implementation Method 1
at least one among the cover window, the adhesive layer and the polarizer is applied with a permittivity reduction processing
Implementation Method 2
forming an electric field with an electric charge penetrated from the cover window into the panel layer
Data Source
AI summary
A display panel can prevent a Greenish phenomenon by preventing a shift phenomenon of a transistor inside a display layer, by applying a permittivity reduction processing on a component disposed upon a panel layer. The display panel can include a cover window, an adhesive layer disposed below the cover window, a polarizer disposed below the adhesive layer, and the panel layer disposed below the polarizer. Further, at least one among the cover window, the adhesive layer and the polarizer can be applied with a permittivity reduction processing.