GLARE REDUCTION

Glare Reduction in glass is possible by two basic methods:
1) Etching the surface to break up reflection patterns, known as non-glare glass
2) Coating the glass with optically designed materials known as anti-reflective glass

Glare reduction may be specified on either single or double surfaces, and may incorporate one or both methods listed above. Untreated or uncoated glass surfaces will reflect approximately 4% or more, depending upon the angle of incidence and index of refraction of the light hitting each surface (front and back). Applying glare reduction methods to untreated glass can significantly reduce this percentage of reflected light. Determining the type of non-glare glass to specify is based upon several factors:  Level of Gloss desired, finished resolution of glass, haze and light transmission desired,  Anti-Newton effects desired, single- or double-sided etching, choice of coatings, and cost trade-offs.

Non-glare glass is available in several quality and etching levels: from picture frame quality to display quality, and from 10 to 140 gloss units. Non-glare glass is produced by chemically etching the surface(s) of glass to produce a "bumpy" surface pattern that scatters reflected light. Various processing techniques and parameters result in different levels of scattering. Non-glare glass lends itself perfectly to chemical strengthening, which increases the impact strength of the product.

Anti-Reflective glass (A/R) is created by bonding specially selected materials to the surface(s) of the glass. While uncoated glass has a surface reflectivity of approximately 4% per surface, A/R glass will have a reflection value less than uncoated, ranging down to 0.1% in some cases. A/R glass has several purposes. It may be used to reduce glare, improve the brightness (signal strength) of transmitted images or light beams, or to improve the contrast of an image (signal-to-noise ratio of a beam).

A/R coatings may be placed on flat, concave, convex or complex shaped transparent substrates. Substrates may include but are not limited to commercial soda lime glass, borosilicate glass, special index optical glasses and filters, quartz, and fused silica. A/R glass is produced by several methods: Pyrolytic coating, Dip coating, and Thin film coating. The purpose of these coatings is to reduce the reflected light from the surfaces of glass and/or increase the amount of light transmitted through the glass.

Pyrolytic Coating is a coating placed on glass as the substrate glass is formed at the primary manufacturer of the glass. "Pyro" means heat and the coating is created at the high temperatures found in the manufacturing of the glass substrate. It is a commercial grade glass generally intended for store windows or other architectural applications.

Dip Coating on glass is accomplished by dipping the glass into tanks containing proprietary materials and bonding agents and then "firing” the coating onto the surface to create a bond. Dip coating may be performed on small parts and lot sizes as well as large sheets and lot sizes. Most dip-coated products do not have anti-reflective performance below 1% surface reflectivity and 1-3% is average. In addition, dip coating may not be as durable as either pyrolytic or thin-film coated products.

Thin Film Coatings are commercially available in several forms and produced by two basic methods:
            ∙ Evaporative Coatings
            ∙ Sputter Coatings