US Patent 7967447 Overheat prevention device

An overheat prevention device comprises an inclination angle detector, a cooling module, and a control circuitry. The inclination detector is adapted to detect a first inclination angle and a second inclination angle, which an light source module is subject to relative to a reference plane, and transmit a first inclination signal and a second inclination signal, respectively. In response to the first inclination signal, the control circuitry alters the cooling module from a first operation mode to a second operation mode. In response to the second inclination signal, the control circuitry alters a projection apparatus from the first operation mode to the second operation mode.