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One-way mirrors for upper-level observation deck viewing down into a classroom (University of Wisconsin-Eau Claire) A one-way mirror, also called two-way mirror [1] (or one-way glass, half-silvered mirror, and semi-transparent mirror), is a reciprocal mirror that appears reflective from one side and transparent from the other. The perception of ...
There are many types of dialyte camera lenses. One popular design is perfectly symmetric, which provides good correction for many aberrations.This consists of two air-spaced achromatic doublets arranged back-to-back around a central stop, or four air spaced lens elements in total: the outer pair is biconvex and the inner pair is biconcave; one example is the Celor.
The optical power of a lens or curved mirror is a physical quantity equal to the reciprocal of the focal length, expressed in metres. A dioptre is its unit of measurement with dimension of reciprocal length, equivalent to one reciprocal metre, 1 dioptre = 1 m −1. For example, a 2-dioptre lens brings parallel rays of light to focus at 1 ⁄ 2 ...
Optical glass refers to a quality of glass suitable for the manufacture of optical systems such as optical lenses, prisms or mirrors.Unlike window glass or crystal, whose formula is adapted to the desired aesthetic effect, optical glass contains additives designed to modify certain optical or mechanical properties of the glass: refractive index, dispersion, transmittance, thermal expansion and ...
A burning apparatus consisting of two biconvex lens. A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction.A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (elements), usually arranged along a common axis.
Single-point diamond turning is an alternate process, in which a computer-controlled lathe uses a diamond tip to directly cut the desired profile into a piece of glass or another optical material. Diamond turning is slow and has limitations in the materials on which it can be used, and the surface accuracy and smoothness that can be achieved. [ 5 ]
As a lens, a transparent sphere of any material with refractive index (n) greater than air (n > 1.00) bends parallel rays of light to a focal point. For most glassy materials the focal point is only slightly beyond the surface of the ball, on the side opposite to where the rays entered.
Uses an equiconvex crown glass lens (i.e. R 1 > 0 with −R 1 = R 2) and a complementary-curved second flint glass lens (with R 3 = R 2). The back of the flint glass lens is flat ( R 4 = ∞). A Littrow doublet can produce a ghost image between R 2 and R 3 because the lens surfaces of the two lenses have the same radii.