Graded index asperhic combiners and display system utilizing same

The optical combiner of claim 6 wherein said graded-index layer is of uniform thickness.

In a display apparatus for combining images, an improved optical combiner comprising:

• a substrate formed of a plastic material and having at least a first surface defining an aspheric contour and a second surface;
• and
• a layer formed on one of said surfaces, said layer comprising a graded-index, diffraction-type reflective coating of photochemical-vapor-deposited material for reflecting radiation within one or more predetermined narrow band ranges of wavelengths impinging on said layer, wherein said layer comprises a selected plurality of materials deposited on said substrate to a thickness having a predetermined profile wherein the stoichiometric composition of said layer as deposited varies in a first predetermined pattern as a function of thickness and in a second predetermined pattern laterally across said substrate to produce successive gradations in said index of refraction in said first and second predetermined patterns as a function of said thickness and as a function of the lateral position on said substrate.

In a head-up display comprising an image source, and an optical combiner interposed between a user and the external scenery for selectively reflecting light from the image source to the user, an improved optical combiner comprising:

• a substrate formed of a plastic material and having at least one aspheric surface;
• and
• a layer formed on said substrate, said layer comprising a graded-index, diffraction-type reflective coating of photochemical-vapor-deposited material for reflecting radiation within one or more predetermined narrow band ranges of wavelength impinging on said layer wherein said layer comprises a selected plurality of materials deposited on said substrate to a thickness having a predetermined profile wherein the stoichiometric composition of said layer as deposited varies in a first predetermined pattern as a function of thickness and in a second predetermined pattern laterally across said substrate to produce successive gradations in said index of refraction in said first and second predetermined patterns as a function of said thickness and as a function of the lateral position on said substrate.

In a head visor display comprising an image source and an optical combiner interposed between a user and the external scenery as a visor for selectively reflecting light from the image source to the user, an improved optical combiner comprising:

• a substrate formed of a plastic material and having at least one aspheric surface, the asphericity of said substrate surface being designed to compensate optical aberrations;
• and
• a layer formed on said surface, said layer comprising a graded-index diffraction-type reflective coating of photochemical-vapor-deposited material for reflecting radiation within one or more predetermined narrow band ranges of wavelengths impinging on said coating wherein said coating comprises a selected plurality of materials deposited on said substrate to a thickness having a predetermined profile wherein the stoichiometric composition of said coating as deposited varies in a first predetermined pattern as a function of thickness and in a second predetermined pattern laterally across said substrate to produce successive gradations in said index of refraction in said first and second predetermined patterns as a function of said thickness and a function of the lateral position on said substrate.