light valve (display) (LV)

Light Valve (LV), light tube, is a projection technology used in projectors, rear projectors and displays. LV technology is similar to the principle of optical switches and works with micromirrors that allow certain color components of the light to pass or block them. As a result, only the desired wavelengths reach the projection surface.

Technically, the light entering the light tube is selected in color filters. Certain color components pass through the dichroic filters, while others enter a different path of the light tube. In the first filtering, the wavelengths are separated from the white of the projector lamp into a blue and yellow component; the yellow, in turn, is separated into red and green. Downstream of the filtering are micromirrors that switch the light in the light tube. If the three colors are switched, then any color can be projected.

Schematic structure of the light tube, Light Valve (LV)

The LV method distinguishes between the reflective method and the transmissive method, in which the light channel is blocked. An example of the use of the light tube are DLP(Digital Light Processing) projectors with Digital Micromirror Device( DMD).