| 摘要 |
<p>PURPOSE:To make it possible to obtain beautiful parting planes and to rapidly produce plural pieces from planar dulled glass by locally heating the center of the planar dulled glass and crushing the dulled glass by thermal stress, thereby producing the pieces. CONSTITUTION:The thermal stress is generated in the planar dulled glass 1 by local heating when the center C of the planar dulled glass 1 is locally heated. Tensile stress is generated around the ordinary temp. dulled glass 1 by this thermal stress and plural cracks are generated when this tensile stress exceeds the permissible tensile stress of the dulled glass 1. The plural pieces are thus rapidly obtd. The cut surfaces of the pieces are formed by expansion of the cracks and, therefore, the cut surfaces of the beautiful specular surface form which is free from ruggedness and is not possible heretofore are obtd. The cracks are generated only in the direction approximately perpendicular to the surface of the dulled glass 1 and there are substantially no crazes appearing on the cut surfaces. The good light transmissive surfaces are thus obtd.</p> |
