US Patent 10303306 Projection display unit

A projection display unit (1) includes a body (10) and an invisible light application unit (30). The body (10) includes a projection optical system and a detection optical system. The projection optical system projects an image onto a projection surface (110). The detection optical system acquires an imaging signal based on invisible light. The invisible light application unit (30) applies the invisible light along a surface in vicinity of the projection surface while being placed on a surface that is an extension of the projection surface. The body (10) is movable with respect to an output opening (31) of the invisible light application unit, and a position of the body is adjustable with respect to the projection surface.