GB1511641A - Missiles - Google Patents

Abstract

1511641 Fuzes DE HAVILLAND AIRCRAFT CO Ltd 13 Oct 1960 [15 Oct 1959] 34963/59 Heading F3A A missile fuze optical system comprises a ring lens adapted to focus incoming radiations approximately on the axis of the missile fuze and a ring reflector to receive such focused radiations on an internal concave reflecting surface for reflection to a radiation-sensitive cell. In Fig. 2 infra-red radiation from two fields of view 12, 14 pass through a window 22 of calcium aluminate glass to a ring lens 24. of bloomed arsenic trisulphide, which focuses the radiation on the axis. The lens 24 is a body of revolution of which the outer surface may be hyperbolic or circular in section and the inner surface rectilinear. From the foci of lens 24 incoming radiation is reflected by elliptical mirrors 42, 56 through filters 34, 48, which pass only a particular range of infra-red wavelengths to the sensitive elements 32, 46 of photo-cells. The fields of view are limited by a central stop 60, stops 38 and 52, and by the edges of mirrors 42, 56. If a source of infra-red radiation enters the field 12 there is a change in the output of photo-cell 32 which may be used to set an explosion initiating circuit which is completed by an impulse from photo-cell 46 when the target enters field 14 provided no undue delay has occurred. A delay may be introduced between the impulse from cell 46 and explosion, the delay being determined by factors such as the duration of the pulses, the delay between the passages through the two fields of view, and the estimated relative velocity.