Projector Screens

Projector Screens Have Undergone A Revolution

 

So if you want to show some of those old 8mm home movies, it will be perfect to just point the projector at the living rule wall, yes? No! Not only will the resulting image be less than crystal clear, the slightest sign of stray light will make thinks even harder to see. Well the best solution would probably be to have them converted to VHS if you still have a player or to DVD if you have moved with the times. If you remain determined to stick with the celluloid, however, today’s projector screens have evolved considerably and should prove far more effective than your living room wall.

In its simplest form, the screen is just a reflective surface. Once little more than a rectangle of canvas coated in white or silver paint, advances in technology has seen the emergence of new materials with far better reflective qualities. These include powder coatings such as titanium dioxide and glass beads both of which provide far brighter images than possible with a painted screen.

Two quite important properties of projector screens are gain and contrast. The gain is a measure of its relative brightness and is derived by comparison with the behaviour of a screen coated with pure magnesium carbonate or titanium dioxide equivalent to a value of 1. While values of 0.8 may be acceptable for use in low light conditions, modern screens can provide gain levels of 2.5 or more and are perfect for use where ambient light levels might otherwise be a problem.

These higher gains are achieved when using projector screens whose reflective surface is coated with minute glass beads.

Where not all the light is reflected parallel to the source, dispersion reduces contrast making it hard to discern finer details.

All Shapes and Sizes
Where overhead projectors are still used, square screens are common but may also be used with digital projectors for economy. This square format represents an aspect ratio of 1:1 but, since most sources are designed to deliver rectangular images screens with asymmetric aspect ratios are more often used. The 4:3 format is found in small or older cinemas while modern projector screens now conform to the popular widescreen aspect ratio of 16:9.

Although flat screens are still the most widely used, curved screens have also been tried with variable results. They do, however, have limitations. The audience must be seated at a fixed and relatively short distance from the screen. If they are positioned either too close to the screen or too far from it, the viewers are likely to experience a variety of undesirable effects such as pincushion or barrel distortion.

Rear Projection
Not all projector screens are designed to reflect. Some, in fact, display their images by transmission. These screens employ a projection source located behind rather than in front and their semi-transparent nature allows a transmitted image to form within them.

Rear projection screens are widely employed in advertising within shopping malls and can also be seen in educational establishments such as museums and zoos. Their relatively compact nature suites these environments quite well but they perform best in the lower ambient light conditions that prevail indoors.

An Evolving Technology
While LED and LCD displays continue to proliferate, the need for improved projector screens continues and companies are still researching ways to upgrade their performance both in terms of their brightness and contrast.

Some researchers have been experimenting with selectively reflective screens that they claim are designed to reflect only the light supplied by the projection source while absorbing stray light from ambient sources. Should their efforts prove successful, this would certainly result in vast improvements to their performance when used for outdoor events such as open air exhibitions.

Other lines of research are directed at the use of louvers integrated into the projector screens that the developers are hopeful will result in a quite significant improvement in contrast.

Versatility is King
Not all of the developments are directly concerned with improving the performance and or advancing the technology. New applications for projection are still being found on a regular basis as are new environments and conditions in which screens are expected to operate. Inflatable screens, mobile screens mounted on towable or self-propelled vehicles are just some of the new requirements.

What is certain is that it is important to seek expert advice when in the market for projector screens. Contact us for time-proven projection solutions and superior products.