Photonics Dictionary

A piece of glass, quartz or other transparent material formed roughly by molding or cutting into the approximate shape and size of the finished part.

The process by which the raster beam in a video tube is cut off during the retracing and sync periods.

A piece of glass having a crude plano surface on each side.

In television, the period during which the electron beam is cut off while the raster returns from the right-hand side of the screen to the left.

A lens blank is a piece of optical material in a raw, unfinished state, typically in the form of a disk or block, from which lenses are eventually fabricated. Lens blanks are made from various...

A mirror blank refers to the initial piece of material from which a mirror is made. It is typically a flat or slightly curved piece of glass or other substrate that serves as the starting point for...

A blank whose basic surface curves are attained by heating and forming a given weight of raw glass; a rough glass blank resembling the finished lens in size and shape. After molding, a precision lens...

A casting consisting of an optical material molded into the desired geometry for grinding, polishing or, in the case of optical waveguides, drawing to the final optical-mechanical specifications.

A formed piece of glass, one surface of which has been ground and polished to the required curvatures.

The initiation of the beam in a cathode-ray tube.

With respect to a television system, a pulse transmitted at the end of each field to break off the cathode-ray beam as it begins the next field.

A substrate refers to a material or surface upon which another material or process is applied or deposited. In various fields, such as electronics, biology, chemistry, and manufacturing, the term...

The process whereby blanks are attached to a block in a position for grinding or polishing.

A piece of glass with a high refractive index that is fused to the major blank.

Also called shining. Grinding and polishing one surface of a blank to permit a more thorough examination for quality.

The generation of a grating on a concave spherical blank by the holographic process. In this way, ghost images and intense stray light are avoided.

A threadlike inclusion within a blank of optical glass. Rarely found in quality optical materials.

The removal of a slight overlap that may be found on a blank or pressing.

The concave portion of a surface, formed on a blank, on which the disk of higher refractive glass will be fused to form a multifocal spectacle lens.

A piece of glass that eventually becomes the bifocal segment as it appears prior to being fused to the blank.

The process whereby a blank or disc is heated to a sufficiently high temperature to sag into a mold having a desired curvature.

A grating with very coarse rulings to match the long wavelengths in the far-infrared region. In the most efficient ruling method, grooves are cut in plane, solid aluminum alloy blanks.

1. A flaw in a blank caused by folding the blank's surface during its formation. 2. The change in the direction of a system's optical axis caused by a reflective component.

In communcations and video signals, the portion of a composite signal between the leading edge of the horizontal blanking pulse and the leading edge of the horizontal synchronization pulse.

A noncrystalline, inorganic mixture of various metallic oxides fused by heating with glassifiers such as silica, or boric or phosphoric oxides. Common window or bottle glass is a mixture of soda,...

A condition in which the solid inclusions within a glass blank are very numerous, such as 25 or more to the square inch.

In the optical shop, the process of positioning and marking a blank or lens before surfacing, cutting and edging.

The production of rough glass lens blanks that are pressed while red-hot to the approximate size and shape of the finished lens, ready for fine grinding and polishing. Large companies often do their...

A blank to which a piece of glass of a different refractive index will be fused to form a multifocal lens.

One or more thin-film layers of optical material deposited on a mirror blank/substrate in order to enhance the way that substrate reflects light. For example of optical materials/optical coatings...

A block that can hold more than one lens or blank.

Optical glass refers to a type of glass specifically engineered and manufactured for use in optical components and systems, such as lenses, prisms, mirrors, and filters. Optical glass is...

The process whereby pitch is broken and the lenses or blanks are removed from the block.

A manufacturing process used to construct substrates for large optical components. Used with IR materials, planform bonding permits the joining of several smaller pieces to be used in place of a...

A blank having basic surface curves attained by forming heat-softened glass that is pressed in a mold.

Trade name for a type of borosilicate glass manufactured by Corning Glass Works, noted for its low coefficient of thermal expansion. Used most often for mirror blanks; not suitable for light...

1. The continuous thin strip marked by the scanning beam. Generally, during return of the scan, the line is blanked out. 2. The thin strip marked by the scanning process and composed of the...

A term used to denote the condition of a few easily visible coarse inclusions within a blank of glass.

In multifocal spectacles, a term used to denote glass with a high refractive index that has been fused to the blank and ground to a curvature, resulting in added power.

A term used to describe a spectacle lens or blank with one surface totally finished.

A metal tool used to hold a number of lens blanks during grinding and polishing.

With respect to television, the returning direction of the electron beam during the vertical blanking period.

A blank area (caused by insufficient inking of the paper) that falls within the range of an intended character stroke in an optical character-recognition system.

Fluid used to aid in examination of semifinished blanks.