Abstract: A digital projection display system includes one or more digital projection displays. Each digital projection display has an external light source producing as an output a light beam, an internal optics system, and a housing in which the internal optics system is received, but wherein the external light source is located external to the housing. A display screen forms one face of the housing. Preferably, an optical fiber extends from the output of the external light source to an input of the internal optics system. Multiple digital projection displays may be illuminated by a single external light source using multiple optical fibers.

Abstract: The method of making a print head of the type that includes a piezoelectric transducer positioned within a metal housing having an annular channel in its inner surface that is sealed by a thin metal diaphragm to form an annular ink chamber. The transducer is in mechanical engagement with the inner surface of the diaphragm. The sudden removal of a voltage applied to the transducer expands the disk to reduce the volume of the ink chamber, rupture the meniscus, and force a droplet of ink from the printing orifice.The housing is formed with an internal taper which permits a groove to be cut readily either by a casting or by a tool entering from the larger end of the central opening in the housing. An aluminum mandrel is tapered to match the taper on the inner surface of the housing and provided with an annular groove that corresponds to the groove in the housing. The mandrel is plated with nickel that will later form the diaphragm. The housing and mandrel are then plated with indium.