Electronic image-display technology dates back more than a century to 1897 when German scientist Karl Ferdinand Braun invented the first cathode ray tube (CRT) scanning device—a CRT with a fluorescent screen, known as the cathode-ray oscilloscope. Since then, CRT-based display technology has proven to be remarkably resilient. It has successfully resisted assaults from many other types of display, despite the fact that CRTs are relatively large and cumbersome, are not solid-state, generate heat and magnetic fields, and they use high voltages. They are, however, effective general-purpose displays that are cost-efficient, reliable, and long-lived—and it is these qualities that explain the longevity of the CRT. In fact, CRTs have become one of today's most ubiquitous technology products—from the living room to the laboratory, it is difficult for most of us to get through a day without seeing at least one CRT display.
Now, though, it seems this is beginning to change as more specialized display types chip away at the overall market—and create new opportunities. Lightweight flat-panel displays are already well-established because of the need created by laptop computers. And the advent of very small devices such as pocket computers and cell phones is creating a whole new high-volume market for very small displays—volumes high enough to warrant large-scale investment in design and development. As such devices get smaller so must the displays: one such microdisplay—based on CMOS technology and organic light emitting diodes—is featured on this month's cover and on page 55.
The use of electronic displays for promotion in the retail environment has been limited by such factors as size, viewing angle, brightness, and mobility of current display technologies. Newly emerging flexible displays may change this too, opening up an entirely new market for optoelectronic displays (see p. S5).
At the "front end" of image display, the technology involved with capturing and storing images is also undergoing a massive upheaval as optoelectronics moves into an arena that was once the almost exclusive preserve of film. Even at the consumer level, digital cameras can produce images with a quality equivalent to film and they are also blurring the distinction between "still" and "movie" photography—some digital cameras can record short movie sequences and sound. And as the supporting infrastructure catches up with these developments, one has to wonder how much longer film can dominate (see p. 109).