Metallurgical microscope objective

Claim 1

A MICROSCOPE SEMI-OBJECTIVE HAVING A MAGNIFICATION PER SE OF 16.0X AND HAVING TOGETHER WITH AN ADJACENT OPTICALLY ALIGNED NEGATIVE CORRECTOR LENS A RATED MAGNIFICATION OF 80.0X AND A NUMERICAL APERTURE OF SUBSTANTIALLY 0.85, THE SEMI-OBJECTIVE AND CORRECTOR LENS TOGETHER PRODUCING AN IMAGE OF EXCELLENT FLATNESS WHICH IS WELL CORRECTED FOR DISTORTION AND ASTIGMATISM AS WELL AS ALL OTHER CHROMATIC AND MONOCHROMATIC ABERRATIONS, THE SEMI-OBJECTIVE BEING FREE OF GHOST REFLECTIONS PRODUCED BY THE AIR GLASS LESN SURFACES WHEN A VERTICAL ILLUMINATOR IS USED, SAID SEMI-OBJECTIVE COMPRISING: A FRONT COMPOUND LENS MEMBER DESIGNATED I WHICH IS SPACED AT AN AXIAL DISTANCE S1 REARWARDLY FROM AN OBJECT SURFACE AND WHICH INCLUDES A FRONT CONCAVEPLANO LENS ELEMENT DESIGNATED IA WHICH LIES IN CONTACT WITH A PLANO-CONVEX LENS REAR ELEMENT DESIGNATED IB ALONG THE PLANO SURFACES, THE AXIAL THICKNESSES OF SAID ELEMENTS BEING DESIGNATED T1 AND T2 RESPECTIVELY, A SINGLET POSITIVE MENISCUS LENS MEMBER DESIGNATED II HAVING A CONCAVE SURFACE FACING SAID OBJECT SURFACE, SAID SINGLET BEING SPACED AT AN AXIAL DISTANCE DESIGNATED S2 REARWARDLY FROM MEMBER I AND HAVING AN AXIAL THICKNESS DONATED BY T3, A SECOND DOUBLET LENS MEMBER DESIGNATED III SPACED AT AN AXIAL DISTANCE S3 REARWARDLY OF MEMBER II AND INCLUDING A FRONT DOUBLE CONCAVE LENS ELEMENTS IIIA WHICH LIES IN ENTIRE CONTACT WITH A REAR DOUBLE CONVEX LENS ELEMENTS IIIB, THE RESPECTIVE AXIAL THICKNESSES OF SAID FRONT AND REAR ELEMENTS BEING T4 AND T5 RESPECTIVELY, A THIRD DOUBLET LENS MEMBER DESIGNATED IV WHICH IS SPACED AT AN AXIAL DISTANCE DESIGNATED S4 REARWARDLY OF MEMBER III, MEMBER IV INCLUDING A FRONT CONVEX-CONCAVE LENS MEMBER DESIGNATED IVA WHICH LIES IN CONTACT ALONG AN INTERFACE WITH A REAR DOUBLE CONVEX LENS ELEMENT DESIGNATED IVB, THE AXIAL THICKNESSES OF ELEMENTS IVA AND IVB BEING DESIGNATED T6 AND T7 RESPECTIVELY, AND A REARMOST DOUBLET LENS MEMBER DESIGNATED V WHICH IS SPACED AT AN AXIAL DISTANCE DENOTED S5 REARWARDLY FROM MEMBER IV AND INCLUDES A FRONT NEGATIVE MENISCUS LENS ELEMENT DESIGNATED VA WHICH LIES IN CONTACT ALONG AN INTERFACE WITH A REAR POSITIVE MENISCUS LENS ELEMENT DESIGNATED VB WHICH HAS A CONCAVE SURFACE FACING REARWARDLY, THE AXIAL THICKNESSES OF ELEMENTS VA AND V BEING DESIGNATED T8 AND T9 RESPECTIVELY AND THE AXIAL SPACE BETWEEN MEMBER V AND THE AFORESAID REARWARD CORRECTOR LENS BEING DESIGNATED S6, THE SPECIFIC VALUES FOR THE LENS PARAMETERS WHICH RELATE TO THE SEMI-OBJECTIVE PER SE BEING SUBSTANTIALLY GIVEN IN THE TABLE HEREBELOW WHEREIN -FI TO -FV AND -FIA TO FVB REPRESENT RESPECTIVELY THE EQUIVALENT FOCAL LENGTHS OF THE AFOREMENTIONED LENS MEMBERS AND LENS ELEMENTS RESPECTIVELY, THE MINUS (-) SIGN SIGNIFYING NEGATIVE FOCAL LENGTHS, SAID TABLE INCLUDING THE AFORESAID LENS THICKNESSES T1 TO T9 AND AIR SPACES S1 TO S6, THE AFORESAID VALUES BEING GIVEN IN TERMS OF F WHICH REPRESENTS THE EQUIVALENT FOCAL LENGTH OF THE SEMI-OBJECTIVE COMBINED WITH SAID CORRECTOR LENS, SAID TABLE FURTHER INCLUDING THE SPECIFIC ABSOLUTE VALUES SUBSTANTIALLY FOR THE REFRACTIVE INDICES DESIGNATED ND(IA) TO ND(VB) AND ABBE NUMBERS DESIGNATED V(IA) TO V(VB) OF THE GLASSES USED IN THE AFORESAID SUCCESSIVE LENS MEMBERS AND ELEMENTS,