Head-up display apparatus including means for displaying three dimensional aircraft vertical path line

Claim 1

Low profile head-up display apparatus for displaying an image including aircraft navigational symbology and an aircraft vertical path line to the pilot of the craft, comprising: means for generating the image including a cathode ray tube with a phosphor plane on which the image is generated, and a face plate having an outer surface and an inner surface adjacent the phosphor plane for transferring the image to said outer surface; a curved combiner which is viewed by the pilot; means disposed between the image generating means and the combiner for transmitting the image away from the generating means and for rotating said image into alignment with the optical axis of the combiner including a U-shaped image conduit having an input surface disposed in intimate contact with the face plate outer surface and rotating the symbology at the outer surface to a conduit outer surface in alignment with the optical axis of the combiner; means arranged with the transmitting and rotating means for transmitting the aircraft navigational symbology to the combiner so that said symbology appears as a real world infinity overlay including a contour element having an input surface disposed in intimate contact with the conduit outer surface and a curved output surface; means arranged with the transmitting means for transmitting the vertical path line to the combiner so that said line appears to extend from a point just forward of the craft to a point at infinity including a wedge having an input surface which is curved to match the curved output surface of the contour element and is in intimate contact therewith, and a sloping output surface.