Patent ID: 8675276

Claim:
An objective comprising: a focusing lens group comprising at least one focusing lens, each focusing lens having diameter less than approximately 100 millimeters, the focusing lens group configured to receive light energy and transmitting focused light energy; a field lens group comprising at least one field lens, each field lens having diameter less than approximately 100 millimeters and configured to receive said focused light energy and transmit intermediate light energy; and a Mangin mirror group comprising at least one Mangin mirror element having a flat surface, each Mangin mirror element having diameter less than 100 millimeters and configured to receive said intermediate light energy and provide controlled light energy through an immersion substance to a specimen, said Mangin mirror group positioned between the field lens group and the specimen, wherein the flat surface of at least one Mangin mirror element is proximate the immersion substance and at least one Mangin mirror element in the Mangin mirror group comprises two reflective surfaces; wherein each focusing lens and each field lens is formed from a single glass material, and further wherein every component of said Mangin mirror group, said field lens group and said focusing lens group is aligned along a received light energy axis, and further wherein the two reflective surfaces of the at least one Mangin mirror element in the Mangin mirror group are mirrored surfaces separated by a nonzero distance along the received light energy axis.