Liquid Crystal Display Flickering Prevention via Insulating Layer
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Solution Overview
Problem
Liquid crystal display devices often experience image flickering, which leads to user fatigue and reduced usability, necessitating a solution to prevent flickering while maintaining good display quality.
Innovation Solution
A liquid crystal display device configuration featuring reflective electrodes made of Al, Ag, Cu, or their alloys, with alignment films containing polyimide derived from polyamic acid and treated with an isocyanate compound to reduce carboxy group reactivity, and a liquid crystal composition with negative dielectric anisotropy, minimizing ion and radical formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If reflective electrodes made of metal (Al, Ag, Cu) are used in transmissive-type and transflective-type liquid crystal display devices, then the display brightness and reflectivity are improved, but the alignment films deteriorate due to charge interactions and radical formation, causing flicker
Solution Approach 1:
An insulating layer is introduced as an intermediary between the reflective electrode and the alignment film. This insulating layer acts as a mediator that prevents direct charge interactions and radical formation from affecting the alignment film, thereby eliminating flicker while preserving the reflective electrode's brightness enhancement function.
Solution Approach 2:
The reflective electrode structure is transformed into a composite material system consisting of the reflective electrode, insulating layer, and alignment film. This composite structure combines the optical benefits of metal reflective electrodes with the protective function of the insulating layer, resolving the contradiction between brightness improvement and alignment film stability.
2Stability of the object's composition
If alignment films are placed directly on reflective electrodes to provide anchoring force for liquid crystal molecules, then the pretilt angle and liquid crystal alignment are improved, but the alignment films deteriorate due to charge interactions with metal electrodes, causing flicker
Solution Approach 1:
The insulating layer serves as a protective intermediary between the reflective electrode and alignment film. It maintains the alignment film's anchoring function for liquid crystal molecules while shielding it from harmful charge interactions and radical formation, thus preserving both alignment quality and film durability.
Solution Approach 2:
The interface between the reflective electrode and alignment film is segmented by introducing the insulating layer. This segmentation separates the electrical charging function of the electrode from the molecular alignment function of the alignment film, allowing each component to perform its function without causing deterioration to the other.
3Duration of action of moving object
If the liquid crystal display device operates for extended periods, then the display functionality is maintained, but flicker occurs due to alignment film deterioration from continuous charge interactions, reducing usability
Solution Approach 1:
The insulating layer is applied beforehand to the reflective electrode to provide protective cushioning against charge interactions and radical formation. This preventive measure shields the alignment film from deterioration during extended operation, eliminating flicker and maintaining display quality over time.
Solution Approach 2:
The insulating layer converts the harmful charge interactions and radical formation into a beneficial protective barrier. By allowing controlled charge accumulation in the insulating layer, the system prevents direct harmful effects on the alignment film, transforming a potential failure mechanism into a protective function that enables long-term stable operation.
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
The solution effectively prevents flickering and enhances display image quality by reducing charge interactions and radical formation, leading to improved durability and power efficiency.
Implementation Method 1
The polyimide is derived from a polyamic acid and contains a side chain represented by the following Formula (1) (where the side chain represented by Formula (1) contains a carbonyl group bonded to a main chain of the polyimide)
Implementation Method 2
The alignment films exert an anchoring force on liquid crystal molecules contained in the liquid crystal composition and impart a predetermined pretilt angle thereto
Implementation Method 3
The liquid crystal composition contained in the liquid crystal layer contains a compound containing an alkoxy group... has negative dielectric anisotropy
Data Source
AI summary
A liquid crystal display device includes an element substrate, a counter substrate, a liquid crystal layer sandwiched between the element substrate and the counter substrate, reflective electrodes placed on a surface of the element substrate that is located on the liquid crystal layer side, and a pair of alignment films each of which is placed on a corresponding one of a surface of the element substrate that is located on the liquid crystal layer side and a surface of the counter substrate that is located on the liquid crystal layer side. A liquid crystal composition contained in the liquid crystal layer contains a compound containing an alkoxy group. The alignment films contain a polymer including polyimide. The polyimide is derived from a polyamic acid and contains a side chain represented by Formula (1).