Liquid Crystal Optical Device Spacer and Adhesive Layer Design
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Solution Overview
Problem
Existing liquid crystal cells with flexible substrates face challenges in maintaining cell gap stability and adhesive force between base layers, particularly under external pressure, leading to defects like cell gap collapse and liquid crystal flow/crowding.
Innovation Solution
The optical device incorporates a liquid crystal element film with a specific structure, including a first and second base layer, a liquid crystal layer, and intermediate layers, which are designed to maintain cell gap stability and attachment force while minimizing defects like pressing or crowding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a pressure-sensitive adhesive layer is used to bond the first base layer and second base layer, then attachment force between base layers is achieved, but the structure becomes vulnerable to external pressure due to very low modulus of the adhesive layer
Solution Approach 1:
The patent employs a composite structure consisting of a rigid spacer layer and a flexible pressure-sensitive adhesive layer working together. The spacer layer provides mechanical strength and structural support to resist external pressure, while the adhesive layer ensures strong attachment between the first base layer and second base layer. This composite approach allows the bonding structure to simultaneously achieve both strong adhesion and pressure resistance.
2Stability of the object's composition
If the cell gap is maintained using conventional methods, then cell gap stability is achieved, but defects such as cell gap collapse or liquid crystal flow/crowding occur under external pressure in autoclave process
Solution Approach 1:
The patent introduces a dedicated spacer layer as a separate functional component between the first base layer and second base layer. This spacer layer is specifically designed to maintain the cell gap, while the pressure-sensitive adhesive layer handles the bonding function. By segmenting these functions into separate layers, the spacer can be optimized for mechanical strength to resist external pressure during autoclave processing, preventing cell gap collapse and liquid crystal defects.
3Strength
If adhesive is applied only on column surface or wall surface to fix spacers, then adhesive force is provided, but micro-stamping process becomes highly difficult and adhesive thickness and area become uncontrollable
Solution Approach 1:
The patent extracts the adhesive function from the spacer structure by using a separate pressure-sensitive adhesive layer. This eliminates the need for complex micro-stamping processes to apply adhesive on column surfaces. The adhesive layer can be uniformly applied over the entire surface, simplifying the manufacturing process while maintaining strong bonding between the base layers and spacers.
4Strength
If adhesive is applied in sufficient quantity to ensure bonding, then attachment force is improved, but adhesive is highly likely to be pushed out during lamination and may contaminate alignment film or liquid crystals
Solution Approach 1:
The patent uses a pressure-sensitive adhesive layer with controlled thickness and properties that provides sufficient bonding force locally at the interfaces between the first base layer, second base layer, and spacer layer. The adhesive layer is designed to be thin enough to prevent pushing out during lamination while maintaining adequate attachment force through its pressure-sensitive characteristics, thereby avoiding contamination of the alignment film and liquid crystals.
Data Source
AI summary
An optical device is disclosed herein. In some embodiments, an optical device includes a first outer substrate, a second outer substrate, a liquid crystal element film positioned between the first and second outer substrates, intermediate layers positioned between the first outer substrate and the liquid crystal element film and between the liquid crystal element film and the second outer substrate, respectively, wherein a sum of the total thicknesses of the intermediate layers is 1,600 μm or more. The optical device can secure structural stability and good quality uniformity by maintaining the cell gap of the liquid crystal element film properly, having excellent attachment force between the upper substrate and the lower substrate, and minimizing defects such as pressing or crowding in the bonding process of the outer substrates.