Laminated Glazing with Thin Adhesive Layer for IR Coating
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Solution Overview
Problem
Incorporating an infrared reflecting coating on a plastic carrier ply into laminated glazing can cause optical distortion, particularly due to the texture of commercial polyvinyl butyral (PVB) during lamination, leading to issues like 'orange peel' or 'apple sauce' effects, which are exacerbated when a suspended particle device (SPD) film is in its darkened state.
Innovation Solution
A laminated glazing construction with a thin adhesive layer of 6µm to 100µm thickness between the glazing material and the infrared reflecting coating, which contacts the obscuration band, allowing for smooth surface adhesion despite the band's non-smooth surface, and a second adhesive layer of 0.38mm to 0.76mm thickness to maintain structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an IR reflecting coating is deposited on a plastic carrier ply, then heat reflection capability is improved, but optical distortion occurs due to texture embossing
Solution Approach 1:
A smooth adhesive layer is introduced as an intermediary between the textured PVB and the IR reflecting coating. This adhesive layer has a dual function: it adheres to both the textured surface and provides a smooth substrate for the IR coating, thereby preventing the texture from being embossed onto the coating while maintaining structural integrity.
2Manufacturing precision
If a thin adhesive layer is used, then optical distortion is reduced, but adhesion strength may be compromised
Solution Approach 1:
The adhesive layer is positioned locally between the PVB and IR coating interface, where it performs its critical function of providing a smooth surface. The thinness of this specific local region (compared to conventional uniform thickness) reduces optical distortion while the adhesive properties ensure sufficient bonding strength at this critical interface.
3Object-affected harmful factors
If the SPD film is in the darkened state, then privacy protection is improved, but optical distortion becomes more visually apparent
Solution Approach 1:
The smooth adhesive layer is applied in advance to prevent texture embossing before the IR coating is deposited. This preliminary action ensures that even when the SPD film is in the darkened state and optical distortion would normally be more visible, the distortion is minimized from the outset, maintaining visual quality across all operational states.
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 configuration reduces optical distortion and allows for the production of high-quality laminated glazings with acceptable adhesion, even on non-smooth surfaces, enhancing visibility and functionality, especially when an SPD film is used.
Implementation Method 1
incorporating an infra red reflecting coating deposited on a plastic carrier ply into a laminated glazing
Implementation Method 2
there being a layer of adhesive between the first pane of glazing material and the infra red reflecting coating
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A laminated glazing is described comprising a first pane of glazing material having a first major surface and an opposing second major surface, there being an obscuration band on the second major surface extending around a portion of the periphery of the first pane such that the second major surface is not smooth. A first adhesive layer having a thickness of between 6μm and 100μm contacts a portion of the second major surface of the first pane of glazing material and a portion of the obscuration band. The laminated glazing also has a carrier ply carrying an infra red reflecting coating wherein the first adhesive layer is between the first pane of glazing material and the carrier ply.