Abstract: A system (100) for combining multi-spectral images of a scene (102) is disclosed. The system (100) is compatible with a viewing system (104) for viewing the scene (102) in a first spectral range. The viewing system (104) has an objective lens (110), an image intensifier (112) and viewing optics (114). There is a detector (128) for viewing the scene (102) in a second spectral band. The detector (128) has an image output (129) representative of the viewed scene. A display (132) for receiving and displaying the image output is provided. There is a collimator (134) for receiving and projecting the displayed image. A beam mixer (118) is provided for receiving both the viewed scene in the first spectral band and the displayed image and conveying the combined images to the viewing system (104) to construct the combined multi-spectral images of the scene. The system may also be used stand-alone without the viewing system (104).

Abstract: A method of achieving a focusing adjustment of an optical assembly, and of releasably locking this focusing adjustment, is described. A night vision weapon sight (10) which implements this method includes an objective lens assembly (14), an eyepiece lens (18), and an image intensifier tube (20) receiving light via the objective lens in order to provide an image via the eyepiece lens. The objective lens assembly includes a base portion (32) into which a lens housing (34) is threadably received. The threaded engagement of the base portion and lens housing is locked by a collet-like array of radially flexible fingers (42) each having a conical outer surface. A locking collar (44) having a conically tapering inner surface threadably engages the lens housing (34) and engages the collet fingers (42). Locking of the locking collar (44) is ensured by threaded engagement of a locking ring (54) with the locking collar (44) such that the prevailing torque tightens both of a pair of threaded engagements of opposite hand.