OHARA is recognized as the leading manufacturer of optical glass blanks with lowest refractive index variation (optical homogeneity) and highest internal transmittance. Many of our glass types can be supplied in "high homogeneity" form. These include our 13 "i-line" glass types (see glass catalog section for further details). Worldwide semiconductor equipment manufacturers are well aware of the high end performance of OHARA's i-line glasses. Please note, all OHARA i-line glass types are designated with the suffix "Y". The material process controls utilized in our production of i-line glasses are evident in the basic high quality of all other OHARA glass types. Every step of production, from melting to annealing, is precisely controlled to insure the highest level of quality.