Screen Seam Joining With UV Adhesive Backer Strip
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Solution Overview
Problem
Conventional methods for joining screen materials, such as cinema front projection screens, face challenges in minimizing optical distortion of the local surface normal at seams, which can lead to visible imperfections and affect the screen's appearance, especially in high gain profiles and polarization-preserving systems.
Innovation Solution
A method involving the use of a UV-curable adhesive with low to zero wicking properties, applied as a pressure-sensitive adhesive (PSA) on the backer strip, which adheres to the substrates on the side opposite the optically functional coating, minimizing distortion and ensuring minimal shrinkage, thereby maintaining the screen's surface normal consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional joining methods are used to join vertical strips, then the screen can be manufactured, but optical distortion at the seam affects screen appearance and visibility
Solution Approach 1:
A backer strip is introduced as an intermediary element between the first and second substrates. This backer strip serves as a mediator that provides a bonding surface for the adhesive while minimizing direct contact and potential distortion at the seam interface. The backer strip acts as a buffer that helps maintain surface normal consistency across the join.
Solution Approach 2:
The adhesive properties are specifically selected and controlled - using UV-curable adhesive with low to zero wicking characteristics and minimal shrinkage upon curing. These parameter changes in adhesive behavior ensure that the bonding process does not introduce significant distortion or surface normal changes at the seam.
2Strength
If adhesive is applied to join substrates, then strong bonding is achieved, but adhesive wicking can contaminate optically functional material
Solution Approach 1:
The backer strip serves as an intermediary barrier that prevents direct adhesive contact with the optically functional coating on the substrates. The adhesive is applied to the backer strip rather than directly to the substrates, eliminating the wicking pathway to the optical material.
Solution Approach 2:
The adhesive is specifically selected with low to substantially zero wicking properties. This parameter change in adhesive behavior ensures strong bonding while preventing the harmful wicking effect that would contaminate the optically functional material.
3Strength
If adhesive shrinks during curing, then bonding strength increases, but surface distortion and optical effects worsen
Solution Approach 1:
The adhesive is specifically selected and formulated to exhibit minimal shrinkage upon UV curing. This parameter change in adhesive behavior allows the bond to achieve sufficient strength without the harmful surface distortion and optical effects that would result from significant shrinkage.
4Illumination intensity
If high gain profile is used to preserve polarization, then optical performance improves, but surface normal distortion becomes more visually observable
Solution Approach 1:
The backer strip acts as an intermediary that helps distribute and equalize stresses across the seam interface. This mediation prevents localized surface normal distortions that would be particularly visible in high gain profiles, while maintaining the optical performance benefits of the high gain material.
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 approach effectively minimizes the optical effect of distortion around the seam to a just noticeable difference, ensuring high tensile strength and durability while maintaining the screen's optical properties and surface integrity, suitable for high throughput manufacturing processes.
Implementation Method 1
The third piece of material may adhere to the seam by using an adhesive such as a PSA, which may be a curable adhesive and in one embodiment, may be cured with UV radiation
Implementation Method 2
The adhesive may exhibit low to substantially zero wicking through the seam to the optically functional material
Data Source
AI summary
The present disclosure describes a manufacturing method for seaming materials. The process may be suitable for manufacturing high performance projection screens using a number of methods including, but not limited to, conventional (convert-before-coating) methods, or convert-after-coating methods. An objective of the present disclosure is to identify a process which may substantially minimize distortion of the local surface normal in the vicinity of the join.