Abstract: A projection lens includes a first lens group, a second lens group and an aperture stop. The first lens group is disposed between a reduced side and a magnified side. The second lens is disposed between the first lens group and the magnified side. The second lens group has a light incident surface, a reflective surface and a light emitting surface, the light incident surface faces the first lens group, the light emitting surface faces a projection surface, the light incident surface, the light emitting surface and the first lens group are disposed at a single side of the reflective surface, and at least one of the light incident surface, the reflective surface and the light emitting surface is a freeform surface. The aperture stop is disposed between the first lens group and the second lens group. Moreover, a projection apparatus including the projection lens is also provided.

Abstract: Provided is an intelligent AV type fire detection system for a large or high-rise building comprising smoke detectors, a controller, activated by any one smoke detector detecting a fire, alarms activated by the controller, image fetching devices wherein one image fetching device nearest the scene of fire is activated by the controller for generating an AV signal, and a communication module. The controller is adapted to generate an AV fire signal contained images from the scene of fire, and the communication module is adapted to receive the AV fire signal from the controller and transfer the AV fire signal to recipients including a fire department and a police department via a telephone company. The recipients thus can directly confirm whether a fire breaks out in a very short time, resulting in a saving of precious time for extinguishing fire.