The present invention relates to an optical glass for an optical path, having a refractive index of at least 1.55, an Abbe number of at least 48 and a specific gravity of at most 2.90 and being excellent in chemical durability, having a chemical composition of:

Mode coupling using grating of ridges and furrows to curve the fibre along a zig-zag path are associated with an index matcher which surrounds the fibre. The average axis of the zig-zag fibre coincides that of the matcher. Light travels along lines all at the same angle to the axis of the matcher and pass through via a conical optical end surface thereof. The optical surface converts the said rays into a parallel beam for coupling with large aperture optical means such as a photo-cell or a LED.

An optical system for an optical encoder of the type having an optical code disc with a plurality of code tracks, and a multichannel photodetector for receiving modulated light from the code tracks, the optical system comprising a light source for producing a line of light, an optional collimating lens for receiving divergent rays of light from said light source and for directing the light in generally parallel rays toward the code disc, an objective lens disposed between the collimating lens an...

There is provided an optical adder for accurately and additively specifying variable optical attenuation, which comprises a quarter wave plate disposed on an optical axis for changing an incident linearly polarized light beam emanating from a light source to a circularly polarized light beam; and one or more neutral density filter plates all disposed on the optical axis next to said quarter wave plate for attenuating the incident circularly polarized light beam respectively additively by a prede...

Optical information generating system for use in display or recording apparatus. The system is characterized by a rotatable character mask in the shape of a drum which has a plurality of character fonts alternately disposed along the longitudinal axis thereof. The drum is displacable along its longitudinal axis so that each font can be independently moved into cooperative relationship with a source of illumination.

An optical mirror essentially consisting of a material containing silicon dioxide, for example, quartz glass, comprising a reflective plate, a carrier plate, and a supporting frame intermediate said plates and connecting them to each other and having a honeycomb structure consisting of a plurality of hexagonal cells, in which the supporting frame is composed of a plurality of Y-shaped elements and the outer longitudinal edges of the three wings of each of these elements are welded together with ...

Apparatus for determining the magnitude and sense of the frequency difference between two identically sensed circularly polarized light beams comprising a beam splitter and respective pairs of analyzers and photodetectors. The light beams impinge on the beam splitter such that the transmitted component of one beam and the reflected component of the other beam are directed through one analyzer onto a related photodetector while the reflected component of the one beam and the transmitted component...

Means are illustrated for electronically exciting phosphor material to provide a source of photon energy for pumping active negative temperature media. Preferably the phosphor has a fast decay time and is so chosen that its emission spectrum substantially matches or coincides with the absorption spectrum of the active negative temperature medium. The source of electrons may be a conventional cathode, or alternatively, one of special construction.

An optical interferometer of the coherent light type with which distances are measured by counting the total number of interference fringes produced when one reflector of a pair in the interferometer is moved through the distance to be measured. The movable reflector which is also translatable normal to the direction of measurement, is a roof prism having its reflective surfaces elongated in this direction. Photoelectric detectors are provided on opposite sides of a beam splitter for each provid...

An optical printer has a camera and several projectors driven by stepping motors. Provision is made to control these motors so that they may be driven in synchronization or the projector motors may be driven out of synchronization and independently of the camera drive. Provision is also made to insure that the motors always stop in a predetermined home position, get up to full speed after rotating through a predetermined arc and begin to slow down with a predetermined arc of the home position.