US Patent 11592731 Projection lens and projection device

A projection lens has a first rotary tube, a first fixed tube at which the first rotary tube is rotatably mounted, a first protrusion portion that is provided at the first rotary tube and that protrudes from the first rotary tube, and a first abutment surface that is provided at the first fixed tube and that abuts upon the first protrusion portion. The projection lens includes a first engaging portion at which the first protrusion portion and the first abutment surface include first engaging portions that face each other in a direction of a first incidence-side optical axis and a first pressing portion that presses the first protrusion portion against the first abutment surface.