An optical reflector is disclosed having a glass base substrate which may be in a spherical form. The substrate has six thin alternate high and low index of refraction dielectric layers vacuum deposited on it. The high index material is first deposited directly on the substrate and the finally deposited is of a low index of refraction material.

A color development composition for color photography containing an aromatic primary amine developing agent and a cyan coupler represented by the following general formula ##SPC1## Wherein R represents a member selected from the group consisting of a hydrogen atom, a methyl group and an ethyl group and X represents a member selected from the group consisting of a hydrogen atom and an acyl group.

Optical retro-reflector in particular for purposes of interferometry. It has the form of a sphere and is fashioned from an optically refractive material, the index of refraction of which is at least approximately 2, but by preference precisely 2. The reflecting surface of the sphere is coated with a film of reflecting material, preferably vapor-deposited metal. The retro-reflector can be manufactured cheaply and with a high level of surface quality. It has a high degree of reflecting power.

A hand retroviewer for use in verifying a document having a retro-reflective image bearing layer which is substantially transparent under ordinary diffuse light viewing conditions to provide viewing of images on an underlying surface. The viewer housing has a viewing passageway therethrough and a beam splitter having a specular reflectance of at least 60 percent is mounted in the viewing passageway. A lamp and a condensing lens which combine to produce a virtual image of the light source that ha...

The invention relates to a reflector system for positioning a medical instrument or of body parts of a patient or for any determination of position, which is characterized by reflectors (3, 4, 5) that are configured as transparent retroreflective spheres and may consist of a material with a refractive index of preferably 1.9.

Retroreflective assembly comprising: a) a transparent globule having a first, uncoated part-spherical surface portion for reception of incident light; a second, substantially flat surface portion opposite the first surface portion; and a third, toroidal surface portion intermediate the first and second surface portions, the toroidal surface having a radius of curvature smaller than the radius of curvature of the first part-spherical surface portion; b) a monolayer of externally reflecting transp...

Cellular, encapsulated-lens retroreflective sheeting comprising: (1) a base sheet of a monolayer of retroreflective elements partially embedded in a binder layer which typically is white or comprises a whitening agent; (2) a cover sheet disposed in spaced relation from the layer of retroreflective elements; and (3) a network of narrow intersecting bonds or seal legs that extend between the cover sheet and the base sheet and comprise binder material thermoformed at the point of contact between th...

A duct for magnetohydrodynamic thermal-to-electrical energy conversion apparatus, which is provided with at least a pair of anode electrodes and cathode electrodes, the cathode possessing excellent erosion or corrosion resistance characteristics being made of an alloy consisting of a refractory metal and an adhesive metal, the fine grains of the refractory metal being bonded through the adhesive metal.

An eyecap for a compact camera comprising a frame in lateral U-shape having three side walls, a cap of a flexible material securely engaged with said frame through a receiving opening, and a rubber plate forming an adhesive member for securing the eyecap on a camera, the rubber plate also being adhered to an inner side of the frame, whereby the photographer can conveniently and clearly look at the object to be photographed and carry the compact camera with the eyecap conveniently and compactly f...

A retro-reflector includes means at least substantially to focus a substantially parallel beam of light from a source of light onto and substantially at right angles to a surface of the retro-reflector when there is relative motion between said source and the retro-reflector along a line which is inclined to a straight line between said source and the retro-reflector, said surface having alternating bands of greater and lesser reflectivity to modify the reflected light repetitively during said r...