Photonics Dictionary: C

In a visual optical system, the axial distance from the last mechanical surface of the eyepiece to the exit pupil.

A microscope eyepiece designed for use with apochromatic objectives. Since apochromatic objectives are undercorrected for lateral color, these eyepieces are overcorrected for that aberration.

Equipment for testing an observer's color vision. Some tests require the identification or ordering of colored samples. The commercially available examples include: the Ishihara plates, on which...

Change of sensitivity of the eye leading to changed color perception.

A coherent fiber bundle (CFB), also known as a coherent fiber optic bundle, is an assembly of multiple optical fibers arranged in a specific geometric pattern to maintain the spatial coherence of...

A compound prism consisting of an assembly of small prisms cemented together that is used in a coincidence rangefinder to transmit the images from the two objectives to a single eyepiece for viewing.

An optical instrument used to determine the distance to a target being viewed. Two similar optical systems view the target via 45° mirrors at the ends of a fixed baseline. One system creates the...

1. An eyepiece or magnifier with a scale at its image plane. That scale is placed in contact with an object, permitting direct measurement of its size. 2. Also called traveling stage and traveling...

Two microscopes that are coupled on a common stand, the two images being projected side by side in the field of view of a single eyepiece for comparison.

1. A solid figure whose base is a circle and whose sides taper upward evenly to a point or apex. Light rays diverging from or converging upon a point are sometimes referred to as a cone of light. 2....

The radiography of small objects having detail too fine to be seen by the unaided eye. The resulting negative, when optically enlarged, can be examined.

1. In optics, the bending of light rays toward each other, as by a convex or positive lens. 2. Turning in the eyes to view a near object. 3. In a television picture tube, the crossing of the...

Convex is an adjective used to describe a surface or shape that curves outward, bulges, or has a rounded and outwardly extending appearance. In the context of geometry or optics, a convex shape is...

The transparent front layer of the eye. Light entering the eye is refracted (converged) by the outer surface of the cornea.

The internal lens of the eye. It is semielastic to permit changes in its power when focusing on objects at near distances.