Display arrangements for head-up display systems

Claim 1

A display arrangement for a head-up display system comprising: an optical projector arrangement comprising a display device for presenting luminous data to be displayed and a lens system for developing at an image plane a real image of the luminous data so presented; and a combiner assembly comprising: a first tuned reflective optical film supported at a position such as to intercept the forward line of sight from an eye position prescribed for a user of the arrangement; and second and third tuned reflective optical films supported between said image plane and said first film, with the third film nearer said image plane, at a position such as not substantially to obstruct the user's view through said first film from said eye position; the positional relationship between said first, second and third films, and said image plane being such that light from said projector arrangement within a prescribed waveband is first incident on said third film at an angle at which said third film is not tuned for reflection and accordingly is transmitted by said third film; such that the light thus transmitted by said third film is incident on said second film at an angle at which said second film is tuned for reflection; such that the light thus reflected at said second film is incident on said third film at an angle at which said third film is tuned for reflection; such that the light thus reflected at said third film is incident on said second film at an angle at which said second film is transmissive, and such that the light thus transmitted by said second film is incident on said first film at an angle at which said first film is tuned for reflection, thereby to reflect the light to said eye position.