Relatively wide-angle apochromatic objective lens system

Claim 1

A RELATIVELY WIDE ANGLE APOCHROMATIC SUBSTANTIALLY SYMMETRICAL OBJECTIVE LENS SYSTEM COMPRISING: (A) A FIRST FRONT LENS COMPONENT OF NET COLLECTIVE EFFECT; (B) A FIFTH REAR LENS COMPONENT OF NET COLLECTIVE EFFECT; (C) SECOND, THIRD, AND FOURTH SPACED LENS COMPONENTS DISPOSED BETWEEN SAID FIRST AND FIFTH LENS COMPONENTS, EACH COMPRISING AT LEAST THREE CLOSELY ASSOCIATED LENS ELEMENTS; (D) SAID SECOND LENS COMPONENT HAVING A NET POSITIVE DIOPTRIC POWER AND HAVING INDEX OF REFRACTION DIFFERENCES BETWEEN ADACENT LENS ELEMENTS LYING WITHIN THE RANGE 0.03 TO 0.09 AND INCLUDING AT LEAST ONE ELEMENT OF NEGATIVE DIOPTRIC POWER AND A DISPERSIVE POWER FOR THE BLUE-VIOLET END OF THE SPECTRUM CHARACTERISTIC OF CROWN GLASS AND HAVING A CONCAVE EXTERIOR SURFACE ON THE SHORT CONUGATE SIDE OF A CURVATURE LYING WITHIN THE RANGE 3 TO 5 RELATIVE TO THE EQUIVALENT FOCAL LENGTH OF THE SYSTEM; (E) SAID THIRD LENS COMPONENT BEING OF GENERALLY BICONCAVE FORM AND HAVING A NET NEGATIVE DIOPTRIC POWER AND HAVING INDEX OF REFRACTION DIFFERENCES BETWEEN ADACENT LENS ELEMENTS WITHIN THE RANGE OF 0.02 TO 0.12 AND COMPRISING TWO LENS ELEMENTS OF POSITIVE DIOPTRIC POWER ENCLOSING A THIRD LENS ELEMENT OF NEGATIVE DIOPTRIC POWER; (F) SAID FOURTH LENS COMPONENT HAVING A NET POSITIVE DIOPTRIC POWER, HAVING AN OVER-ALL MENISCUS FORM WITH A CONVEX EXTERIOR SURFACE ON THE SHORT CONJUGATE SIDE, HAVING ITS INTERIOR SURFACE ON THE SHORT CONJUGATE SIDE CONVEX TO THE LONG CONJUGATE SIDE OF THE SYSTEM, AND HAVING INDEX OF REFRACTION DIFFERENCES BETWEEN ADJACENT LENS ELEMENTS WITHIN THE RANGE OF 0.01 TO 0.09 COMPRISING AT LEAST ONE LENS ELEMENT OF A DISPERSIVE POWER FOR THE BLUE-VIOLET END OF THE SPECTRUM CHARACTERISTIC OF CROWN GLASS; (G) THE TWO OUTER LENS ELEMENTS OF EACH OF SAID SECOND, THIRD, AND FOURTH LENS COMPONENTS HAVING HIGHER INDICES OF REFRACTION AND HIGHER INDICES OF DISPERSION V THAN THE CENTRAL LENS ELEMENT THEREOF AND AT LEAST ONE OF THE EXTERIOR SURFACES AND AT LEAST ONE OF THE INTERIOR SURFACES OF SAID THIRD LENS COMPONENT BEING ASPHERIC AND EFFECTIVE SUBSTANTIALLY TO CORRECT RESPECTIVELY AXIAL ABERRATION AND AT LEAST ONE TYPE OF OFF-AXIS ABERRATION; (H) AND EACH OF SAID SECOND AND FOURTH LENS COMPONENTS COMPRISING TWO LENS ELEMENTS OF POSITIVE DIOPTRIC POWER ENCLOSING A THIRD LENS ELEMENT OF NEGATIVE DIOPTRIC POWER, THE TWO OUTER LENS ELEMENTS OF EACH OF SAID SECOND, THIRD, AND FOURTH LENS COMPONENTS HAVING HIGHER INDICES OF REFRACTION AND HIGHER INDICES OR DISPERSION V THAN THE CENTRAL LENS ELEMENT THEREOF AND AT LEAST ONE OF THE EXTERIOR SURFACES AND AT LEAST ONE OF THE INTERIOR SURFACES OF SAID THIRD LENS COMPONENT BEING ASPHERIC AND EFFECTIVE SUBSTANTIALLY TO CORRECT RESPECTIVELY AXIAL ABERRATION AND AT LEAST ONE TYPE OF OFF-AXIS ABERRATION.