Throughout the 1960s, the management at RCA thought LCD displays
were too difficult to commercialize and sent their engineers and
researchers involved in LCDs off into the hinterlands. After watching
[Ben Krasnow]‘s efforts to build a liquid crystal display, we can easily see why the suits thought what they did. It’s an amazing engineering feat.
Before building his own version of an LCD (seen above in action), he
goes through the mechanics of how LCDs operate. Light enters the
display, goes through a polarizer, and is twisted by a liquid crystal
material. The first successful LCDs used two types of liquid crystals –
chiral and nematic. By combining these two types of molecules in the
right proportion, the display can ‘twist’ the polarized light exactly 90
degrees so it is blocked by the second piece of polarizing film in the
display.
Besides getting the right crystals and engineering processes, another major hurdle for the development of LCDsdisplays
is transparent electrically conductive traces. [Ben], along with every
other LCD manufacturer, uses a thin layer of indium tin oxide, or ITO.
By embedding these clear electrodes in the display, segments can be
built up, like the seven segment displays of a calculator or a bunch of
tiny dots as found in a TV or computer monitor.
In the end, [Ben] was able to build an extremely simple single-segment LCDdisplay
out of a pair of microscope slides. It does modulate light, just
barely. With a lot of work it could be made in to a calculator type
display but for now it’s an awesome demonstration of how LCDs actually
work. http://www.youtube.com/watch?v=d4QFNWBSZYg
Besides getting the right crystals and engineering processes, another major hurdle for the development of LCDs
In the end, [Ben] was able to build an extremely simple single-segment LCD
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