Miniature built-in projection device

The utility model relates to a projector, particularly to a miniature built-in projection device. Aiming at the problems that an existing projection device is relatively large in optical loss, relatively large in size and inconvenient to carry, a built-in projection device is disclose, including an optical engine, a lens group, a condensation and dodging device, a light source and a projection lens. One side of the optical engine is equipped with the lens group, the lens group and the condensing and dodging device have a connection part, the bottom of the condensing and dodging device is equipped with the light source, and the built-in projection device is characterized in that the other side of the optical engine is equipped with a projection information output optical fiber; the other end of the projection information output optical fiber is connected with the projection lens; and the connection part between the lens group and the condensing and dodging device is an optical input optical fiber. The device is small in size, simple in structure, high in energy utilization ratio and high in transmission efficiency, and is arranged in a mobile terminal, energy utilization efficiency is improved, an optical path structure is simplified, and portability of a micro-projector is truly realized.