09-09-2017, 01:29 PM
Liquid crystal over silicon (LCoS or LCOS) is a miniaturized reflective active matrix liquid crystal display or "microdisplay" using a liquid crystal layer on top of a silicon backplane. It is also known as a spatial light modulator. LCoS was initially developed for projection TVs, but is now used for selective wavelength switching, structured lighting, near-eye displays and optical pulse configuration. By way of comparison, some LCD projectors use transmissive LCD, allowing light to pass through the liquid crystal.
On an LCoS display, a CMOS chip monitors the voltage on square reflective aluminum electrodes buried just below the surface of the chip, each controlling a pixel. For example, a chip with XGA resolution will have 1024x768 plates, each with an independently addressable voltage. Typical cells are about 1-3 centimeters square and about 2 mm thick, with a pitch of pixels as small as 2.79 μm. A common voltage for all pixels is supplied by a transparent conductive layer made of indium oxide and tin on the cover glass.
On an LCoS display, a CMOS chip monitors the voltage on square reflective aluminum electrodes buried just below the surface of the chip, each controlling a pixel. For example, a chip with XGA resolution will have 1024x768 plates, each with an independently addressable voltage. Typical cells are about 1-3 centimeters square and about 2 mm thick, with a pitch of pixels as small as 2.79 μm. A common voltage for all pixels is supplied by a transparent conductive layer made of indium oxide and tin on the cover glass.