Patent GB-1250461-A (GB)
IPC: G02B27/01
Filed: 1968-10-25
Abstract: 1,250,461. Eyeglass device. BELL AEROSPACE CORP. Oct.25, 1968, No.50707/68. Heading G2J. A visual presentation device, of particular use in piloting and navigating aircraft, comprises an eyeglass frame 10 having side bows 18 or a band 66 and an eye-piece support 14, reflecting curved eye-pieces 12 the inner surfaces of which are concave, image projecting means 42 mounted on the side bows and including a projecting lens (44), Fig. 4 (not shown) to project an image which is reflected by the eye-pieces to the wearer. The side bows 18 each embody a lens support cylinder 42, fibre optics bundle support 48 and fibre optics bundle 46 which are contained within the support cylinder 42. Knurledknob 50 affords interpupilary adjustment of the eye-pieces 12 and nose pieces 58 may also be adjusted. Eye-pieces 12 have zero refracting power and their concave surfaces are coated to reflect wavelengths between 560 and 580 millimicrons. Each projection lens (44), Fig.4 (not shown) is composed of two simple lenses to allow variable magnification of the image transmitted by the fibre optics bundle 46. The image can be made to appear either from infinity or from a focal plane other than infinity the first case being appropriate for aircraft armament while the second would be used wherein an instruction pattern is superimposed upon a plane at a certain distance from the viewer. In a modification, Fig.5 (not shown) sighting reticle (68) and a beamsplitter (60) are incorporated to combine an image from the sighting reticle (68) with the image from the fibre optics bundle 46. The information supplied via the fibre optics bundle 46 may be flight information such as roll and pitch sensors, engine temperatures and oil pressures, thus enabling the pilot to simultaneously view the environment ahead and an instrument display panel provided by the eyeglass. The display may be presented as in Figs.6A, 6B (not shown) wherein a roll bar (78) is rotated and a source of light (84) and beam-splitter (82) provide an image of the bar (78) to rotate in front of the eye to indicate roll and pitch together with the image of the various displays to provide the Fig.6B (not shown) display. In another embodiment, Fig.7, 8, 11 (not shown) cathode ray tubes (104), (104<SP>1</SP>) are used in lieu of the fibre optics 46 and in addition pellicles (108), (108<SP>1</SP>) are used to project images to the eyes along the same optical axis as the background image. Mirrors (110), (110<SP>1</SP>) reflect the output from the cathode ray tubes to be projected by the field lenses (112), (112<SP>1</SP>) towards the pellicles. A framework (120), Fig.10 (not shown) serves as a protection for the pellicles (108), (108<SP>1</SP>) since they are thin membranes. The eye-pieces (102) and (102<SP>1</SP>) may be replaced by others for different types of flight conditions, or alternatively lenses which have varying density as a function of incident light may be employed to provide a proper contrast between background and image light intensities. In Fig.11 (not shown) the cathode ray tube (104) projects a video image while the cathode ray tube (104<SP>1</SP>) projects the same radar image. The eye-pieces (102), (102<SP>1</SP>) in this case may be opaque and with such means a pilot may fly and bring an aircraft into blind landing. When both sensors (104), (104<SP>1</SP>) project video images a three dimensional image is seen by the pilot after proper adjustment of the eye-pieces (102), (102<SP>1</SP>), and the curved eye pieces provide a wide angle presentation.