Objective lens system for imaging instrument

An otological imaging instrument for viewing an ear interior, said instrument comprising:

• an instrument housing including a frusto-conical insertion portion at a distal end thereof;
• an electronic imager disposed in a proximal end of said instrument housing opposite said distal end;
• illumination means disposed within said insertion portion for illuminating the interior of the ear for viewing;
• and
• a retrofocusing lens system for reducing an object onto said proximally disposed imager;
• wherein said retrofocusing lens system includes a first group of optical elements positioned within the frusto-conical insertion portion of said instrument housing opposite from said proximal end and a second group of optical elements disposed proximally from said first group of elements and aligned therewith along an optical axis, said first group of optical elements including at least one negative lens and said second group of optical elements including a plurality of lenses having an aggregate positive optical power,
• whereby an optical image is imaged at a single imaging plane located at said proximally disposed imager using said retrofocusing lens system without the need of intermediate imaging planes wherein said distal insertion portion includes an inner tip housing and an outer tip housing, each of said inner tip housing and said outer tip housing being coaxial with said optical axis wherein the interior of said outer tip housing and the exterior of said inner tip housing define a second annular space, said instrument further including insufflation means for stimulating the tympanic membrane, said insufflation means including an insufflation path provided by said second annular space wherein said inner tip housing includes a plurality of circumferentially disposed flattened sections to provide vents for said insufflation means.