Abstract:
A structure to be monitored for damage and a method of monitoring the structure for damage are provided. The structure has a coating thereon, the coating defining a surface having characteristics which vary in a predetermined manner with damage to the structure. The surface has a series of conductive tracks applied thereto and in intimate contact therewith such that the said predetermined variation of the surface characteristics will vary the resistance of the series of conductive tracks in a predetermined manner in order to determine both location and extent of damage.
Abstract:
A display apparatus for use in displaying an image to a viewer (4), comprising an optical waveguide (8) arranged to receive image-bearing light (2) into the optical waveguide to guide the received image-bearing light therealong to an output part (5) of the optical waveguide for output therefrom. A combiner (70) is arranged adjacent to the output part of the optical waveguide for reflecting image-bearing light output by the waveguide in a direction which passes back through the optical waveguide and for allowing light (6) from an external scene to pass through the combiner in said direction through the optical waveguide to combine with the reflected image-bearing light so that the image-bearing light overlays light from the external scene for viewing by a viewer.
Abstract:
A structure to be monitored for damage and a method of monitoring the structure for damage are provided. The structure has a coating thereon, the coating defining a surface having characteristics which vary in a predetermined manner with damage to the structure. The surface has a series of conductive tracks applied thereto and in intimate contact therewith such that the said predetermined variation of the surface characteristics will vary the resistance of the series of conductive tracks in a predetermined manner in order to determine both location and extent of damage.