Projector
Throws the image onto an external surface instead of owning it itself. Three dominant technologies: DLP, LCD, LCoS.
DLP (Texas Instruments): millions of tiny mirrors tilt to reflect light. Sharp image, "rainbow effect" can occur on single-chip versions. LCD: three LCD panels (RGB) the light passes through. Colourful but lower contrast. LCoS (Sony SXRD, JVC D-ILA): hybrid — liquid crystals on a reflective chip, the best black levels. Modern light sources: lamp (legacy), laser (long life, pricey), LED. Short-throw / ultra-short-throw are modern home installs that can sit ~30 cm from the wall.