Abstract: A bifocal double group lens assembly, sequentially from the object side, comprises: a stationary first lens group with a negative refractive power, a second lens group with a positive refractive power being moveable along optical axis. The second lens group, at two different positions, can focus appropriately on an infinitely distant object when moving along the optical axis. When the lens assembly is in the wide angle mode, and the object to be shot moves from an infinite distance to a near point, the second lens group will move toward the object side for focusing. When the lens assembly is in the Tele mode, and the object to be shot moves from an infinite distance to a near point, the second lens group will move toward the image side for focusing. A linear driver is employed to move the second lens group for executing the function of two-section zoom and continuous focus.

Abstract: The present invention discloses an improved wireless audio output assembly for projectors, which comprises a system unit having a projector circuit therein and a projector lens disposed on the exterior of the system unit, and the system unit has a card-type wireless audio output circuit installed therein and a wireless active speaker installed on the exterior of the system unit, so that a projector can be used as a standalone device without connecting to external cables to read data from a memory card, view video images, and read audio/video signals of an optical disk. The projector can be upgraded to the user's desired wireless audio output circuit by inserting various different cards for the expansion.