Abstract: Collaborative work on an interactive system is facilitated by accurately capturing and displaying information on an interactive system, wherein multiple persons may work together for supplying and receiving information with a single large area display. A large area electronic writing system is provided which employs a large area display screen, an image projection system, and an image receiving system including a light emitting pen. The display screen is designed with the imaging surface in front of the substrate, with a thin abrasion resistant layer protecting the imaging surface from the pen tip. The screen is held together with dowel pins pressed through the layers, and is curved to provide pressure for holding the layers together and mechanical rigidity against flexure during writing. The imaging surface disperses light from both the projection system and the light pen.

Abstract: A technique for producing pixel patterns at different selected wavelengths. A diode laser is repeatedly pulsed and has its temperature changed from pulse to pulse, which causes the output wavelength to change. This allows pixel patterns to be interlaced by the use of dispersive elements such as prisms in the optical train. A temperature shift of about 15.degree. C. provides a wavelength shift of about 30 angstroms, which is usable. A temperature shift of 20.degree. C.-30.degree. C. or more is preferable. The temperature shifts may be accomplished by supplying specific currents below threshold and above threshold. For two-wavelength operation, the laser is driven at a first bias current below threshold for a first non-illumination interval, at a first pulse current above threshold for a first illumination interval, at a second bias current below threshold for a second non-illumination interval, and a second pulse current above threshold for a second illumination interval.

Abstract: A method of fabricating an acoustic ink printhead with an integrated liquid level control layer is presented. With standard photolithographic techniques, acoustic lenses and ink supply channels are defined in a substrate. Apertures are created in a spacer layer plate to define cavities to hold the ink reservoirs for each ejector. Corresponding alignment holes also made in the substrate and in the spacer layer plate. With spheres matching the size of the alignment holes, the spheres engage the alignment holes to precisely align the apertures in the spacer layer plate with the acoustic lenses in the substrate. The plate and substrate are then bonded for an integrated acoustic printhead with liquid level control by capillary action.