Polychromatic mutual alignment device for an aiming apparatus

Claim 1

An aiming apparatus having: a laser delivering a parallel light beam in the near infrared range; a plurality of light receivers to be harmonized with said laser, each operating in a respective one of a plurality of wave length ranges other than near infrared; an aiming mirror arranged for simultaneously controlling light paths from said laser and to said light receiver toward and from an outside scene, respectively; a polychromatic mutual alignment device; optical switching means having one position wherein they direct said parallel light beam toward said aiming mirror and another position in which they direct said parallel light beam toward said mutual alignment device; and adjustment means located on the path of said parallel light beam between said laser and said optical switching means, for angularly altering the path of said parallel light beam; wherein said polychromatic mutual alignment device comprises: an optical mixer having at least two source-forming holes each receiving light delivered in a respective one of said plurality of wave length ranges for which mutual alignment is to be achieved; a plate which is transparent in one of said wave length ranges and reflective in another of said wavelength ranges for combining the two light beams into a common mixer output beam; and a sensor sensitive in the near infrared range; and a parabola mirror having an axis and placed so as to receive the output beam at an angle with respect to said axis, the mixer and the mirror being constructed so that all said source-forming holes are at the focus of the mirror; and wherein said mixer is so constructed that, when the near infrared light beam entering said mutual alignment device is coaxial with said output beam, said sensor is at a distance of the parabola mirror equal to the focal length of the latter and is centered with respect to the near infrared light beam.