A seam in a projection screen viewing surface has never been a popular subject, but it has been a fact of life for virtually every screen manufacturer (and their customers) for decades. Although Draper has improved on our seaming techniques over the years, we recently decided to solve this issue once and for all. This has brought us to the point where we have some exciting news to share, but first, we need to give an overview of seams and what has been done to improve upon them.
To seam, or not to seam?
Traditional Seaming Technologies
Projection screens fall into two general classifications: self supporting, which does not require tensioning to lay flat, and unsupported (flexible), which requires some tensioning method to ensure flatness. This report is focused on flexible, unsupported vinyl surfaces.
It is safe to say that all quality screen manufacturers utilize radio frequency (RF) heat sealing (AKA dielectric sealing) to create their seams. In this process, two pieces of screen fabric are placed between two dies (electrodes). The RF produces heat by exciting the molecules to the point that they melt and create the seam. The generic term for this method is called “tear seam.” The strength of the seal is determined by three factors-
- Sealing current (radio frequency power)
- Sealing time
- Pressure
While the entire procedure is much more complicated than described above, this is a basic snapshot of how screen manufacturers have seamed their viewing surfaces together.
A few years ago, Draper developed proprietary processes that have two important benefits. First, we reduced the valley created when the fabrics are seamed (tear seam); second, we could hide the shiny line created when the fabrics melt together. We believe we provide the best and least conspicuous traditional seams on the market today. Only under the most demanding critical viewing applications will the seam be a factor.
To read more and discover what an optically seamless projection screen is, click here.
