GLOSSARY
OPTICAL QUARTZ PRODUCTS
Aliasing Noise A noise which does not actually exist but is created when the image sensor receives stripe patterns. It is also called a moiré fringe.
Crystal Phase Plate A device in which a phase shift occurs between the ordinary ray and the extraordinary ray, when the two rays pass through the crystal. There are 1/4 wave plate and 1/2 wave plate.
Cutoff Characteristics A characteristic in which spatial frequency (which makes moiré patterns) is blocked.
Depolarizer Rays become polarized after passing through the double refraction plate. The device (depolarizer) transforms such rays into non-polarized rays. It is also called a phase plate or wave plate.
Double Refraction Plate A filter which separates incoming ray into two separate rays: the ordinary ray and the extraordinary ray. It is also called the savart plate.
Extraordinary Ray A light ray that changes its speed in its propagation direction when the incident light separates into two light rays through the double refraction plate.
Infrared Absorbing Glass A glass that absorbs infrared radiation.
Infrared Cut Coating An optical layer that reflects infrared radiation.
Infrared Ray Cut-Off Filter A filter which shuts off infrared rays. Image sensors are sensitive to infrared rays while human eyes are not so this filter is used for color correction. It is available with IR absorbing glass and IR cut coating.
Moiré A false signal. Also called aliasing noise.
Optical Axis The direction of the axis when a double refraction does not occur in the birefringent crystal.
Optical Low Pass Filters A filter which eliminates high frequency input through the lens structure. This reduces the aliasing noise from entering the image sensor of digital still cameras, video recorders, etc.
Ordinary Ray A light ray that does not change its speed to the direction of propagation when a ray is divided into two through the double refraction plate.
P polarized light An electric vector of the light wave, which oscillates parallel to the incident plane.
Polarized light An electric vector of the light wave, which vibrates in one plane.
S polarized light An electric vector of the light wave, which oscillates perpendicular to the incident plane.
Savart Plate Refer to Double Refraction Plate.
Separation Pattern A pattern that is formed by separating the incident light through the double refraction plate.
Ultraviolet Cut Coating An optical layer that reflects ultraviolet radiation.
Wavelength Plate Refer to Crystal Phase Plate.