Published on Jun 05, 2023
From cell phones to iPods to PDAs, we have at our fingertips connectivity with friends and colleagues around the world, libraries of text, music, photos, videos and more. Unfortunately, the displays that we use to view all this information are also small they are flat-panel screens with just a few square inches of display area. No wonder that projectors that display large images from within hand-held electronic devices-Pico projectors are drawing so much attention in the tech world.
With Pico projectors, we can project a full-size image onto whatever is near at hand, whether it be the wall, our shirt, or a piece of paper. Pico projectors represent a core enabling technology for the future growth of portable devices. Pico projectors are the latest technology to prove that big things often do come in small packages. These tiny projectors are embedded in mobile devices to provide large screen displays that can be viewed from anywhere. Pico projectors have an infinite focus that can be projected onto surfaces with any 3D depth profile and remain in focus. The possible applications are various and many. Aside from having a larger format for typical mobile applications, such as reading email and sharing pictures, Pico projectors could be used for business presentations or scientific visualizations.
The first generation of pico projectors hit the market in 2008. They weren’t much clunky little boxes that produced low-quality images and had to be cabled to a computer or PDA. Very few people bought them. Turns out that what people really want is a mobile phone, music player, laptop, or camera that projects big, bright, and sharp images or an extremely tiny plug-in projector compatible with all those devices. This type of projector is available now. In the next generation of pico projectors, they’re coming embedded in cameras, media-storage devices, and a few Smartphone. Over the next few years they’ll be popping up in more products.
There are currently three major competing imager technologies for micro projectors. Texas Instrument’s Digital Light Processing (DLP), scanning-mirror systems, and a handful of LCoS (Liquid crystal on silicon) manufacturers including Micron Technologies and Omnivision. Most micro projectors employ one of these imagers combined with color-sequential (RGB) LEDs in either a single or triple architecture format. Some older models incorporated a single LCoS imager chip with single white LED which is recognized to offer lower cost, high resolution, and fast response at the expense of color quality.
Digital Light Processing was invented in 1987 by Texas Instruments. It is named for its ability to process light digitally with the aid of an optical semiconductor called a Digital Micromirror Device or DMD chip. The DMD chip is comprised of over one million mirrors. The size of each mirror is less than 1/5th the width of a human hair. One-chip DLP systems use a projection lamp to pass white light through a color wheel that sends red-green-blue colors to the DMD chip in a sequential order to create an image on-screen. Only one DMD chip is used to process the primary RGB colors. Three-chip DLP systems use a projection lamp to send white light through a prism, which creates separate red, green, and blue light beams. Each beam is sent to their respective red, green, and blue DMD chip to process the image for display on-screen. One-chip models are said to produce a display of over 16-million colors.
