Abstract: Disclosed is a process capable of precision slicing substrates with a dimension in the linear direction of at least I meter, comprising the following steps: (I) affixing the work piece to a stage; (11) providing multiple essentially parallel, essentially straight wires having a diameter in the range from about 100 ?m to about 600 ?m, and allowing the multiple wires to contact the surface of the work piece; (III) allowing the multiple wires to travel in linear directions, optionally with cutting slurry dispensed thereon; and (IV) allowing the multiple wires to move in the slicing directions relative to the work piece; wherein in step (IV), the multiple wires maintain essentially straight and essentially parallel to each other. The process can be used for slicing silica glass substrates having a diameter large than 2 meters in producing slices thereof with a high surface flatness and a low thickness variation.

Abstract: Disclosed are process and apparatus for inspecting internal inclusions in internally transmissive substrates. The process involves applying a black coating to one major surface of the substrate, submerging the substrate in a refractive index-matching fluid, and scanning the substrate with a collimated light beam. The scattered light signals produced by the inclusions can be detected by the human eye or by using a light detector. By the use of index-matching fluid and the black coating, the signal-to-noise ratio of the process and apparatus are enhanced. A preferred black coating is one cured from an electron beam or photo polymerizable coating composition applied to the major surface. The process and apparatus are particularly suitable for inspecting internal inclusions in an internally transmissive substrate having considerable amount of surface defects or contoured surface that prevent it from inspection in a gas medium.