A projector or image projector is an optical device that projects an image (or moving images) onto a surface, commonly a projection screen. Most projectors create an image by shining a light through a small transparent lens, but some newer types of projectors can project the image directly, by using lasers. A virtual retinal display, or retinal projector, is a projector that projects an image directly on the retina instead of using an external projection screen.
The most common type of projector used today is called a video projector.Video projectors are digital replacements for earlier types of projectors such as slide projectorsand overhead projectors. These earlier types of projectors were mostly replaced with digital video projectors throughout the 1990s and early 2000s, but old analog projectors are still used at some places. The newest types of projectors are handheld projectors that use lasers or LEDs to project images. Their projections are hard to see if there is too much ambient light.
Movie theaters used a type of projector called a movie projector, nowadays mostly replaced with digital cinema video projectors.
Projector Screen Calculators
Naturally, when you’re in the market for a projection screen, there are a lot of things you’ll need to consider before you put your money down. You need to really understand the budget you’re working with, of course. You need to know what your requirements are based on where you’ll be using the projector screen. You’ll need to know what your expectations are as far as image clarity, features, and crispness.
However, some things aren’t quite as easy to figure out. For instance, many people are unsure as to what size projection screen is really the right fit, and it’s not hard to understand why. Size selection isn’t just about choosing an option that physically fits into your available space. It’s about selecting the size that’s appropriate for your anticipated viewing distance and angle. You need to take the specs attached to your projector into consideration.
A projection screen is an installation consisting of a surface and a support structure used for displaying a projected image for the view of an audience. Projection screens may be permanently installed, as in a movie theater; painted on the wall;  or portable with tripod or floor rising models.  as in a conference room or other non-dedicated viewing space. Another popular type of portable screens are inflatable screens for outdoor movie screening (open air cinema).  Uniformly white or grey screens are used almost exclusively as to avoid any discoloration to the image, while the most desired brightness of the screen depends on a number of variables, such as the ambient light level and the luminous power of the image source. Flat or curved screens may be used depending on the optics used to project the image and the desired geometrical accuracy of the image production, flat screens being the more common of the two. Screens can be further designed for front or back projection, the more common being front projection systems, which have the image source situated on the same side of the screen as the audience.
Different markets exist for screens targeted for use with digital projectors, movie projectors, overhead projectors and slide projectors, although the basic idea for each of them is very much the same: front projection screens work on diffusely reflecting the light projected on to them, whereas back projection screens work by diffusely transmitting the light through them.