Optical Device Hard Coating Prevents Light Leakage
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Solution Overview
Problem
Optical devices with active liquid crystal elements or polarizers encapsulated by an adhesive film often suffer from defects such as light leakage and cracks, which affect their performance and durability.
Innovation Solution
An optical device design that includes a hard coating layer on the base layers to prevent defects, featuring a structure with a active liquid crystal element capable of switching between transparent and black modes, utilizing a guest host liquid crystal layer with a dichroic dye guest and a polarizer, and an adhesive film for encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an adhesive film is used to encapsulate the active liquid crystal element and polarizer, then the device can be assembled and sealed, but defects such as light leakage and cracks occur
Solution Approach 1:
A hard coating layer is introduced as an intermediary between the adhesive film and the base layers. This hard coating layer acts as a mediator that prevents direct contact between the adhesive film and base layers, thereby preventing light leakage and cracks while still allowing the adhesive film to perform its encapsulation and sealing function effectively.
Solution Approach 2:
The hard coating layer is applied in advance on the base layers before the adhesive film is applied. This preliminary protective layer cushions and protects the base layers from potential damage caused by the adhesive film, preventing cracks and light leakage defects before they can occur during the encapsulation process.
2Reliability
If a hard coating layer is added to prevent light leakage and cracks, then reliability improves, but device complexity increases
Solution Approach 1:
The hard coating layer is implemented as a thin film coating on the base layers. This thin film approach provides the necessary protective function to prevent light leakage and cracks while minimizing the increase in device complexity and overall thickness, as thin films add minimal structural complexity compared to bulk materials.
3Ease of manufacture
If the optical device uses an adhesive film for encapsulation, then assembly is simplified, but light leakage and cracks occur affecting performance
Solution Approach 1:
The hard coating layer serves as an intermediary that enables the adhesive film to perform its encapsulation function without causing optical defects. The hard coating layer is applied first on the base layers, providing a suitable surface for adhesive film bonding while preventing direct adhesive contact with the base layers that would cause light leakage and cracks, thus maintaining both ease of assembly and optical performance.
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 optical device achieves high contrast ratio and durability by preventing light leakage and cracks, enabling efficient switching between transparent and black modes for various applications like eyewear and vehicle sunroofs.
Implementation Method 1
an active liquid crystal layer capable of switching between at least two or more oriented states of light axes, for example, first and second oriented states, where the active liquid crystal layer comprises a liquid crystal compound capable of switching in an oriented state
Implementation Method 2
a mixture of a host material and a dichroic dye guest is applied
Data Source
Figure 1~5
AI summary
The present application relates to an optical device. The present application provides an optical device capable of varying transmittance, and such an optical device can be used for various applications such as eyewear, for example, sunglasses or AR (augmented reality) or VR (virtual reality) eyewear, an outer wall of a building or a vehicle sunroof.