Multifunction coaxial objective system for a rangefinder

An improved optical catadioptric lens system for a rangefinder suitable for use as part of a night vision goggles system, the improved system including a laser emitter and a laser detector, the improved optical system comprising:

• a viewing optical system;
• an image intensifier adapted for projecting an image to the viewing optical system for viewing;
• a transmitter optical system having an optical axis for transmitting laser energy from the laser emitter;
• a receiver optical system having an optical axis for permitting the laser detector to receive laser energy, wherein the optical axes of the transmitter optical system and the receiver optical system are coaxial in object space;
• and
• at least one optical element having a central obscuration therein included within the receiver optical system, wherein laser energy transmitted by the laser emitter passes through the central obscuration of the optical element.

A night vision goggle and rangefinder, comprising:

• a housing;
• a laser emitter having an optical axis supported within the housing;
• a laser detector supported within the housing;
• a transmitter optical system having an optical axis supported within the housing;
• a receiver optical system having an optical axis supported within the housing;
• a viewing optical system having an optical axis supported within the housing, wherein the optical axes of the transmitter optical system, the receiver optical system, and the viewing optical system are coaxial in object space;
• an image intensifier tube included within the viewing optical system for permitting night vision;
• a first optical element supported within the housing and having a central obscuration therein, wherein a visible image produced by the viewing optical system passes through the central obscuration of the first optical element;
• a second optical element supported within the housing and having a central obscuration therein, wherein laser energy received by the laser detector passes through the central obscuration of the second optical element;
• a third optical element supported within the housing and having a central obscuration therein, wherein laser energy transmitted by the laser emitter passes through the central obscuration of the third optical element;
• a lens having a dichroic coating on one surface in at least one of the viewing optical system and the receiver optical system, for transmitting visible and near infrared light to the image intensifier tube and for reflecting laser energy received by the receiver optical system to the laser detector;
• and
• a pair of focusing wedges for adjusting the focus of the viewing optical system, each focusing wedge being a wedge-shaped optical flat, the pair of focusing wedges being disposed against one another along a plane inclined with respect to the coaxial axis of the transmitter, receiver, and viewing optical systems, whereby focus adjustment is achieved by relative movement between the focusing wedges along the inclined plane.