Digital Light Processing [DLP]
Digital Light Processing (DLP) is a display device based on optical micro-electro-mechanical technology that uses a digital micromirror device. It was originally developed in 1987 by Dr. Larry Hornbeck of Texas Instruments. While the DLP imaging device was invented by Texas Instruments, the first DLP-based projector was introduced by Digital Projection Ltd in 1997. Digital Projection and Texas Instruments were both awarded Emmy Awards in 1998 for the DLP projector technology. DLP is used in a variety of display applications from traditional static displays to interactive displays and also non-traditional embedded applications including medical, security, and industrial uses.
DLP technology is used in DLP front projectors (standalone projection units for classrooms and business primarily), DLP rear projection television sets, and digital signs. It is also used in about 85% of digital cinema projection, and in additive manufacturing as a power source in some printers to cure resins into solid 3D objects.
Digital micromirror device
Main article: Digital micromirror device
In DLP projectors, the image is created by microscopically small mirrors laid out in a matrix on a semiconductor chip, known as a Digital Micromirror Device (DMD). These mirrors are so small that DMD pixel pitch may be 5.4 µm or less. Each mirror represents one or more pixels in the projected image. The number of mirrors corresponds to the resolution of the projected image (often half as many mirrors as the advertised resolution due to wobulation). 800×600, 1024×768, 1280×720, and 1920×1080 (HDTV) matrices are some common DMD sizes. These mirrors can be repositioned rapidly to reflect light either through the lens or onto a heat sink (called a light dump in Barcoterminology).
Rapidly toggling the mirror between these two orientations (essentially on and off) produces grayscales, controlled by the ratio of on-time to off-time.
Color in DLP projection
There are two primary methods by which DLP projection systems create a color image: those used by single-chip DLP projectors, and those used by three-chip projectors. A third method, sequential illumination by three colored light emitting diodes, is being developed, and is currently used in televisions manufactured by Samsung.