The Grating Light Valve Modulator (GLV)
One of the fundamental breakthroughs for this new projector is a tiny linear array of movable mirrors, known as the GLV.
The GLV is a micro-electro-mechanical system (MEMS), in that it is a silicon microchip that happens to have physically movable parts onboard. In this case, the movable parts are tiny mirrors controlled by on-chip electronics. By moving these mirrors, the GLV is able to modulate light and form the basis for a projected display.
To create a GLV device, MEMS techniques are used with ordinary CMOS semiconductor processing to form tiny reflective elements on the surface of a silicon chip. Each of these elements is made up of multiple ribbon-like structures, which can actually be moved up or down over a very small distance (only a fraction of the wavelength of light) by controlling electrostatic forces.
THE GLV ELEMENT
The ribbons are arranged such that each element is capable of either reflecting or diffracting light. This allows an array of elements, when appropriately addressed by control signals, to vary the level of light reflected off the surface of the chip. This control of light can be analog (variable control of light level) or digital (switching of light on or off). Because a GLV device is reflective, it is highly efficient in its use of light.
Given the GLV’s ability to selectively deflect light as shown below, the overall light modulator is then made complete by a mechanism for collecting only the light that has been diffracted, and passing that through to the projection lens.
