Hardness test impression size measurement method - with picture of the impression and its surrounding area reproduced on a surface

摘要

The size of the surface impression is measured. The impression appears dark on a bright surrounding background with the bright and dark surface areas being evaluated by fibre optical devices. Picture sizes of the impression and surrounding area can be varied, and scanning of the fibre optical devices can be changed. The reflection from the hardness impression is retransmitted by a zone plate through a focussing lens on to a tubular lens, to one of the plane faces of which the optical fibre is attached.