Window shade positioning apparatus

An aircraft window shade includes protective transparent window panels, a movable diaphragm (28,30) driven by an electric motor (24,26), an integral control panel (84), and support for remote operation. The shade uses dual sprocket drive (58;60) for positive diaphragm positioning, low wear, and low parts count. The moving diaphragm element remains substantially flat, curving slightly during some phases of positioning. The apparatus replaces a conventional interior window panel and a manual shade with slight change in overall mechanism thickness and weight. Control electronics in the shade can accept a command from a cabin attendant's console to override the local setting and move the diaphragm to a required position, such as fully open for takeoff or landing. The shade supports use of one or more (28,30) independent diaphragms, each of which can be made of dimming (transparent), diffusing (translucent), or light blocking (opaque) material. The shade is compatible with electrochromic transmittance control technology.