Quote:
Originally Posted by Dave A
I need to figure out the difference between a filter and a shutter...
I am missing what the shutters do.
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Well, I may confuse things a bit with a kinda High School science class explanation, but I will take a stab at it:
1. A filter may be as simple as the colored filters used to select a specific portion of a light spectrum, for example a blue filter placed in front of a "white" light source to produce blue illumination.
2. A liquid crystal cell is usually a couple pieces of glass with transparent electrodes (usually tin oxide) arranged in a specific pattern to control the orientation of liquid crystal material that is contained between the two glass pieces, by applying voltage to the electrodes.
3. Color shutters are a combination of LC cells, polarized filters and color polarized filters that can switch the color transmitted by applying voltage to the cell.
Imagine this high school experiment... take 2 pieces of polarized material and observe a "white" light source through the two filters... if you rotate one filter with respect to the other, you will observe a minimum and maximum transmission of light at 90 degrees rotation. If one of the filters is, say blue color polarized material, you will observe a change from white light to blue light as you rotate the filters 90 degrees. Now if instead of mechanically rotating the polarized filters 90 degrees with respect to one another you placed a liquid crystal cell designed to rotate polarized light 90 degrees when voltage is applied to it, you could produce the same optical changes by merely flipping a switch.
jr