Elucidation of F-Value, in Relation to the Angle and Direction of the Incident Ray

Abstract

This is a following-up paper of "The mutual relation between the angle and direction of incident and radiant ray", published in this journal, vol. 21, 1996. In evaluating brilliancy, the F-Values, the ratio of incident ray area to radiant ray area, were used in Ref. 2) (Fig. 10). The F-Values were calculated and graphically represented similarly in this paper, for the cases when incident ray is inclined to the table facet at different angles. It was unexpectedly found that the graphical curves of the F-Value cross on a small area (σ_1=70°, Fig. 14). This unexpected phenomenon gives an explanation to flash and scintillation appearing when a stone is moved.