Variable Scattering Glazing with Thin Glass and Liquid Crystals
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Solution Overview
Problem
Existing electrically controllable glazing with liquid crystals is expensive, heavy, bulky, and difficult to handle, with non-uniform optical performance due to dioptric defects in the glass panes, leading to unacceptable light transmission and high reject rates.
Innovation Solution
The development of multiple glazing with thinner glass panes (less than 5.5 mm) and a layer of liquid crystals (15-60 μm thick) with transparent spacers, using a sealing joint with interruptions to ensure uniform thickness and optical performance, and applying a method to measure and limit dioptric defects for improved reliability and handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If standard thickness glass panes are used, then structural strength is sufficient, but the glazing becomes heavy and bulky
Solution Approach 1:
The patent changes the parameter of glass pane thickness from standard values (6mm or more) to thinner values (3-5.5mm), thereby reducing weight and bulk while maintaining structural adequacy through the optimized liquid crystal layer and sealing design
2Manufacturing precision
If glass panes with dioptric defects are used, then manufacturing is easier and less costly, but optical performance becomes non-uniform with dark and light regions
Solution Approach 1:
The patent establishes specific parameter thresholds for glass pane quality, requiring dioptric defects to be less than 12 E/15 millidioptres, thereby ensuring uniform optical performance while providing clear manufacturing specifications
Solution Approach 2:
The patent replaces mechanical polishing or grinding of glass surfaces with optical measurement and selection criteria, using dioptric defect measurement to qualify glass panes without additional mechanical processing steps
3Reliability
If a thick layer of liquid crystals is used, then optical performance is improved, but the glazing becomes bulkier and harder to handle
Solution Approach 1:
The patent optimizes the liquid crystal layer thickness to a specific range (15-60 μm), which is sufficient to achieve the desired optical performance (variable scattering between transparent and non-transparent states) while minimizing the overall glazing thickness and improving handleability
4Manufacturing precision
If continuous sealing joint is used, then structural integrity is maintained, but uniform distribution of liquid crystals and evacuation of trapped air is difficult
Solution Approach 1:
The patent segments the continuous sealing joint into interrupted sections, creating gaps that allow liquid crystals to distribute uniformly and trapped air to escape during assembly, while maintaining structural integrity through the overall sealing configuration
Solution Approach 2:
The interrupted sealing joint acts as an intermediary structure that temporarily allows liquid crystal flow and air evacuation during manufacturing, then provides structural sealing when assembled, mediating between the needs for uniform distribution and structural integrity
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 results in a compact, reliable, and high-performance glazing with uniform light transmission, reducing dioptric defects and enhancing the optical quality, making it suitable for various applications including vehicles and buildings.
Implementation Method 1
a layer of liquid crystals alternating reversibly between a transparent state and a translucent state by application of an alternating electric field
Implementation Method 2
alternating reversibly between a transparent state and a translucent state by application of an alternating electric field
Implementation Method 3
incorporates spacers, in particular transparent spacers
Data Source
AI summary
A multiple glazing with variable scattering by liquid crystals includes first and second flat float glass sheets sealed on the edge of their internal faces by a sealing joint, in particular made of a given sealing material, in particular essentially organic, first and second electrodes, and a layer of liquid crystals with an average thickness E between 15 and 60 μm inclusive of these values and incorporating spacers. The thickness A of each of the first and second glass sheets is less than or equal to 5.5 mm, and each of the internal faces coated with the first and second electrodes has a dioptric defect score, expressed in millidioptres, of less than 12E/15 where the thickness E of the liquid crystals is in μm.