A portable micro projector is a compact device that can project images onto a movie screen, blank wall or other display medium. Typically, this device is small enough to fit into a pocket, and weighs less than one pound (.45 kilograms). Depending on the price, micro projectors can be very basic in function or may include virtually the same set of features as a full-size projector.
Common specifications for all projectors include lumens, contrast ratio, resolution, and image throw ratio. Lumens are the measure of brightness perceived by the human eye. The American National Standards Institute has a standard for measuring projector lumens, so different models can be reliably compared against each other on this point. The more lumens a projecter can direct in its output, the brighter and easier to read its display will be.
Contrast ratio is the degree to which a projector's display of the color white differs from its black. Generally, high contrast ratios are desirable and offer more accurate, true-to-life colors. Resolution refers to the number of pixels, or individual blocks of visual data, a projector can display. The higher the resolution of a portable micro projector, the more visual data it can display in the same relative space.
Finally, image throw ratio is used to gauge projection size, relative to the distance a projector is placed away from the screen or wall. A portable micro projector that has a throw ratio of 3.0, for instance, will display an image 6 feet (1.82 meters) wide when the projector is set 18 feet (5.5 meters) away from the display. Throw ratio can be an important consideration when considering use, especially in very small or very large spaces. A portable micro projector is generally an excellent choice for use in slightly confined settings.
Micro projectors function by using one of several different display technologies, depending on the manufacturer. Some companies employ microscopic lasers and mirrors to produce an image, while others use either Light Emitting Diode (LED) or Liquid Crystal Display (LCD) technologies. Depending on the pricepoint, a portable micro projector will usually include inputs that allow video or still images to be projected from variety of sources, ranging from DVD™ and Blu-Ray™ players to computers and portable media players. Other optional features that some micro projectors may feature include a battery system, built-in audio speakers, tripod socket, and adjustable feet for fine-tuning the angle of the display.