Abstract: Helmet mounted display apparatus for use in aircraft and rotorcraft includes an image source for generating images that are projected into the pilot's forward field of view by a portion of relay optics that are common to both day and night viewing and interchangeable optical eyepieces, one for daytime viewing and one for nighttime viewing.

Abstract: Helmut mounted display apparatus configured for simulator use includes a pair of visual image sources and a pair of optics arrangements, including relay optic and eyepiece portions thereof, that optically present the image source images into the wearer's forward visual field, a first eyepiece type optimized for daytime luminance conditions, a second type optimized for nighttime luminance conditions, a single eyepiece being releasably engageable to and rotatable about the corresponding relay optic portion, wheeby said eyepiece rotation allows a varying binocular field of view to be displayed to the wearer.

Abstract: Helmet mounted display apparatus for use in aircraft and rotorcraft includes an first image source for generating images comprising pilotage symbol information, a second image source for sensing and generating images of the exterior scene, and relay optical components that optically superimpose the two images together and subsequently project the superimposed image into the observer's forward field of view.

Abstract: A piezoelectric phase modulator for a fiber optic sensor is disclosed. The disclosed modulator is capable of relatively large amplitude mechanical vibrations, i.e., having a large converse piezoelectric effect, while at the same time having a relatively predictable and well-behaved direct piezoelectric effect. This result is accomplished by bonding a relatively active piezoelectric material, such as PZT, to a relatively stable piezoelectric material, such as quartz. An optical fiber may then be bonded to the relatively stable material, or to a structure attached thereto, as part of a fiber optic sensor loop. Excitation of the relatively active piezoelectric material will then produce a mechanical vibration in the relatively stable material and in the attached fiber comparable in magnitude to that experienced by the active material. Several embodiments of the invention are shown which are illustrative of devices which may be made according to the teachings disclosed.

Abstract: Organic photochromic materials comprising a photochromic dye and a resinous material can be stabilized with a protective coating which will protect them from deactivation by exposure to moisture, oxygen, various plastic host materials, reactive chemicals or even normal atmospheric conditions. Useful organic photochromic dyes include the spiropyrans, the spirooxazines, the metal dithizonates, the phenazines, the phenothiazines and other known photochromic compositions. Useful resinous materials include vinyl-type thermoplastics, cellulosic materials, polyesters, epoxy resins and aminoplast resins. The encapsulated photochromic materials of the invention comprise an organic photochromic dye in combination with an organic resinous material enclosed within an outer shell of an inorganic material and find use in the preparation of photochromic plastic films, sheets, ophthalmic lenses such as lenses for sunglasses and in camera lenses and filters.

Abstract: Inorganic photochromic crystalline particles which are particularly useful in ophthalmic quality plastic host materials are formed for instance utilizing a silver halide crystal whose dimensions lie generally in the range between 30 Angstroms and 10,000 Angstroms. The surface of the silver halide crystal is coated with an inorganic material in an effective thickness to render the coating resistant to diffusion from within and to protect the crystal from interaction with host material. The stabilized coated particles can be introduced by known schemes into plastic host materials in order to form photochromic plastic articles useful in the preparation of films, sheets, filters for cameras, wall panels and ophthalmic lenses and other optical devices.

Abstract: Organic photochromic materials comprise a photochromic pigment stabilized with a protective inorganic coating which serves to protect the pigments from deactivation by exposure to moisture, oxygen, various plastic host materials, reactive chemicals or even normal atmospheric conditions. Useful organic photochromic pigments include the anils, hydrazones, semicarbozones, osazones, sydnones, fulgides and others. Inorganic coatings comprising such materials as zinc oxide, titanium dioxide, aluminum oxide, antimony oxide and silicon dioxide are useful in the preparation of photochromic plastic films, sheets, ophthalmic lenses such as lenses for sunglasses and in camera lenses and filters.