Abstract: An optical projector (11) for a two-color head-up display wherein light of a first color from a first data source (15) passes through a first lens arrangement (23) into a first wedge-shaped body (27) wherein the light is, in turn, internally reflected at first and second angled faces (35 and 33) of the body and then exits the body at the first face (35) to pass via a second lens arrangement (25) to the system combiner (13) in a direction at an angle to that which light enters the body, and light of a second color from a second data source (37) passes through a third lens arrangement (41) into a second wedge-shaped body (43) wherein the light is reflected at one (49) of first and second angled faces (47, 49) of the second body and then exits the body at the other angled face (47), which is adjacent the second angled face of the first body, and then passes through the first body to the second lens arrangement, there being a dichroic coating at the interface of the two bodies to effect reflection of light of the

Abstract: A display head (11) for a vehicle head-up display system wherein the display head combiner (35, 37) is pivotally supported by means of two kinematic chains (19, 21, 23, 23', 25, 25') so as to enable the combiner (35, 37) to be moved from an operative position to a stowed position in which the combiner (35, 37) together with its support means (19, 21, 23, 23', 25, 25') is inconspicuous.

Abstract: An angular position sensor, suitably for use in a helmet sight system, comprising a link member (3) connected by first and second (5 and 49) coupling means respectively to first and second fixing means (7 and 57, 59, 63) whereby the sensor may be attached between two bodies (1 and 61) whose relative angular position is to be sensed. The first and second coupling means respectively define axes of permitted angular movement of the first and second fixing means with respect to the link member and are associated with angle sensing means (21, 23 and 51, 53) providing electrical outputs representative of the angular positions of the fixing means about these axes. The sensor further includes a third coupling means (29, 31, 33 or 57, 59) whereby the fixing means may be moved translationally with respect to one another without altering any of the outputs of the angle sensing means.