Patent GB-1212485-A (GB)
Title: Head-up display systems
IPC: G02B27/01
Filed: 1969-04-15
Abstract: 1,212,485. Head-up display systems. INTERNATIONAL BUSINESS MACHINES CORP. April 15, 1969 [May 17, 1968], No.19288/69. Heading G2J. A display system, especially a head-up display system, includes image generating and projection means providing a variable view of the 3-D object, approach path signalling means for indicating the vehicle's position relative to the object, attitude signalling means for indicating the vehicle's pitch, yaw or roll condition, if any, perspective and size selection means associated with said image generating and projection means responsive to said approach path signalling means for projecting an image of the object having the perspective and size related to the vehicle's actual position relative to the object, and image translating means associated with said image generating and projection means responsive to said attitude signalling means for positioning the image selected by said perspective and size selection means in accordance with the vehicle's attitude changes. In preferred embodiments the head-up display is presented to a pilot approaching an aircraft carrier, the image being manipulated to achieve the 6 degrees of freedom of azimuth, depression, image pitch, image yaw, range and roll and is responsive to data received from the carrier in relation to the aircraft. In an optical system Fig.23 a model 160 of a carrier is mounted in a gimbal system for rotation about axes 164, 165, perpendicular to the optical axis 162. An optical zoom lens system 161 is mounted integral with the model gimbal system whereby the carrier model 160 remains on the optic axis when the lens system is pivoted about the centre of the lens 161. Axes of rotation 166, 167 of the lens system charge the location of the image to be projected into the pilots field of view and the pitch and yaw of the aircraft is represented by rotation of the model about axes 164, 165. Roll, seen as angular tilt of model 160, is effected by an additional gimbal 168 on the model support to rotate the model about the optic axis 162. The lens system projects an image on to a screen, via a mirror, a collimating lens then projecting the image on to a beam splitter for viewing by the pitot. If desired the entire optical system of model 160 and lens system 161 may be held stationary and pitch and yaw of the aircraft simulated by rotation of the mirror about two orthogonal axes. An alternative embodiment utilizes a reconstructed real image from a hologram 125 Fig.19. A reconstruction beam 128 is intercepted by a pitch and yaw translation mirror 131 and lens 132, and a perspective selection mirror 130 the real  image being set up on a screen 122. Range information is given by a zoom lens 135 providing variable magnification image on a screen 136 which is then projected to a beam splitter and thence to the pilot. Roll is simulated by rotation about optic axis 140 of mirror 131, lens 132, mirror 130 and hologram 125. This last step can be accomplished in an alternative manner Fig.21. The reconstruction beam is reflected from perspective selection mirror 130 to hologram 125 and the real image set up on screen 122. Zoom lens 135 then forms a magnified image on screen 136. Intermediate lens 135 and screen 136 is a pair of spaced parallel mirror systems 1141, 1140 rotatable about a vertical axis 1142 and a further mirror 145 rotatable about axes 146, 147. Mirror 145 translates the image presented to screen 136 in accordance with pitch and yaw of the aircraft. If desired the vertical image reconstructed from the hologram may be utilized. The display system may be used in a flight simulator or any other vehicle.