Fused image products are used in a variety of medical, scientific, and industrial applications. Common classes of fused fiber products are:
Fiber Optic Faceplates: Fused fiber optic structures used as the input or output face on image or cathode ray tubes. Generally round or rectangular in cross-section, with planar, cylindrical or spherical polished surfaces, faceplates provide a hermetic seal and an effective barrier to the high voltages inside the tube.
Fiber Optic Windows: Fused fiber optic structures used as the input face for solid state imaging devices such as CCDs and photodiode arrays. Typically rectangular in cross-section with planar polished surfaces, the structures are machined to conform to the package configuration of the semiconductor device. Fiber optic windows generally have extremely demanding optical specifications because of the small pixel size of the device receiving the transmitted image.
Image Conduit: Drawn or fused fiber optic structures that transmit images over distances from a few inches to a few feet. Applications are extremely varied, ranging from transferring an image from a signature card to film, to visual alignment of plotters. With quantities ranging from thousands down to a single structure for a custom machine-vision application, image conduit varies greatly in its composition and cross-section in order to be optimized for a particular application.
Light Diffusers/ Filter Plates: Fused fiber optic structures with solid-core fibers. Diffuser plates are useful for angular light discrimination and for breaking or de-focusing light beams.
When utilizing fused fiber optic products, the optical designer should consider the following parameters:
Numerical Aperture (N.A.): The sine of the half-angle at which light (in air) enters a fiber, propagates along its length, and exits at the other end. The N.A. is a function of the refractive indices of the core and cladding glasses. Common formulations include .35, .56, .66, .8, and 1.0. Other numerical apertures are available on a custom basis.
Fiber Diameter: Determines the resolving power, or resolution (expressed in Lp/mm, or pixel density), of the image bundle. Typically 6 - 8µm, fiber diameters can range from more than 100µm to a practical downward limit of 3µm.
Extramural Aborption (EMA): A light-absorbing material (usually glass) optionally introduced into the fiber optic structure. EMA absorbs stray light that exits a fiber when a ray exceeds the critical angle determined by the numerical aperture.
CHI has a well-earned reputation for responding quickly and effectively to unique design requirements for fused image products. Our focus is to provide faceplates, windows, image conduit, and custom fused fiber optics to customers needing unusual geometries and the highest optical quality. Our fused fiber optics are characterized by very low optical distortion, a minimum of optical blemishes, and a general absence of boundary defects known as fixed pattern noise, or chicken wire . With a substantial inventory of optical glasses ready for use, CHI is able to deliver the specific solution to the most challenging optical design that are available (round, hexagonal, rectangular, square, and custom)and fused.