US Patent 6873460 Retractable rear projection display

A retractable screen system suitable for portable, hand held computing and communication units joins a number of optical sheets to form a rollable, extendible and retractable projection sheet. The resulting folded optical system provides a lightweight, portable unit. Telescoping arms allow the screen to be extended and stowed quickly and easily. High screen resolution is afforded by multiple mechanisms that scan concurrently. Beam indexing of the screen permits the precise alignment via feedback, and an embodiment fit for military, command and control applications.