Abstract: Fiber optics and photovoltaic devices for optically controlling a conventional Electro-Hydraulic Valve (EHV) without need for external wiring. One laser, one fiber and one photocell located at the EHV are electrically passive, and inherently reliable. The system is much less susceptible to hard-over failure and unsymmetrical control because changes in any one of these elements will affect both directions equally.

Abstract: A three-phase angular position sensor is described in which three beams of light having polarization directions rotated 60.degree. to each other are passed through a polarizer, the rotational position of the polarizer representing an angle to be measured. The intensities of the beams transmitted through the polarizer uniquely encode its angle over a 180.degree. range. This range may be doubled, for example, by including a binary track. A two-phase angular position sensor is also described in which two beams have polarization directions oriented 45.degree. with respect to one another.

Abstract: An optical position sensor comprising an encoder plate (52) that includes a variable density code pattern (54) is disclosed. Disposed in contact with the encoder plate is a bearing plate (58) having a read head (60) rigidly mounted thereto. The encoder plate (52) is coupled by a flexible aligner (62) and a shaft (64) to an object whose position is to be sensed such that the bearing plate (58) remains in contact with the encoder plate (52) as the object moves. Thus, no gap occurs between the read head and the encoder plate. A series of channels (70) disposed in the bearing plate contain a lubricant having approximately the same index of refraction as the encoder plate (52) and bearing plate (58). The lubricant reduces abrasion between the encoder plate and bearing plate as well as reduces reflective losses.

Abstract: A position sensor for determining the position of an encoded surface applied to an element. Several embodiments of a position sensor (30, 100, 110, 110', and 200) are disclosed. In each embodiment, light at a reference wavelength and at a test wavelength travel along a common optical path until separated by an interference filter (40, 120, 214). A test beam comprising light at the test wavelength is transmitted through the interference filter toward an encoded surface (44, 216), which reflects a portion and transmits another portion of the test beam. The transmitted portion of the test beam is reflected by a mirror (50, 222) which is disposed adjacent an opposite surface of a rotatable disk (54) or a linear encoder (220) from that on which the encoded surface is applied. The transmitted portion of the test beam is reflected by the mirror along a first optical path (74, 130, 224), while the portion of the test beam that is reflected by the encoded surface travels along a second optical path (68, 138, 230).

Abstract: A technique for trimming or making a position sensor that includes a movable encoder having a track extending along a dimension of the encoder, the track having an optical property that varies with position. The sensor also includes a light source for directing an optical input beam onto the track, such that the encoder responds by producing a modulated beam having an intensity that is a function of the optical property. The intensity of the modulated beam thereby encodes the position of the encoder. The technique of the invention comprises the steps of determining the intensity of the modulated beam with the encoder at a selected position, producing a corresponding measurement signal, and comparing the measurement signal to a predetermined target value. If the difference between the measurement signal and the target value exceeds a tolerance, the optical property at the position is modified, for example using a laser beam to ablate a portion of the track.

Abstract: A light transmission filter for transmitting a beam of light of any wave length. The filter is made up of a pattern of opaque figures positioned along a transparent substrate. The spacing between figures is varied along the substrate so that the beam of light intercepted by the filter is variably transmitted as a selected function of the longitudinal position of the filter relative to the beam of light. The spacing of the figures along the substrate is selected to achieve a light transmission characteristic for the film in accordance with a desired mathematical function. An optical analog position sensor for sensing the position of a movable member along a prescribed path including the optical transmission filter attached to the movable member with the substrate having a longitudinal configuration corresponding to the prescribed path. The intensity of a fixed beam of light transmitted through the filter indicates the position of the member.

Abstract: An optical encoder produces a reference signal and compensates for any instability in intensity of a light source which reads the encoder. The optical encoder comprises a movable encoding element having an analog track of variable transmissivity, and a chopping element for alternately transmitting light from the source through the analog track and around the analog track. Light transmitted through the analog track comprises an information signal and light transmitted around the analog track comprises the reference signal. The chopping element comprises an optical switch or a rotatable or stationary element havnig an alternating series of opaque and transparent sections.

Abstract: A device for determining the position of the boundary between first and second substances having different refractive indices that may be used to determine the level or volume of liquid in a container. The apparatus comprises a plurality of optical sensors (21-26), a pulse source (30) for generating an optical source pulse, an interface (40) responsive to the source pulse for producing an optical response pulse, and a receiver (60) for measuring the duration of the response pulse. The sensors are positioned along a line that intersects the boundary (16) between the first (18) and second (12) substances over a range of boundary positions. Each sensor is adapted to vary one of its optical properties depending upon whether it is in the first or second substance. The interface produces the response pulse such that the response pulse has a time duration proportional to the number of sensors that are in the first substance.

Abstract: An optical switching element utilizes a spherical diaphragm mounted for snap-action movement between a concave and convex shape. A light beam is directed through a small aperture to impinge on the diaphragm. The aperture is positioned at a distance from the diaphragm equal to the radius of curvature of the diaphragm to obtain maximum reflection of the light when the diaphragm is in its concave shape. Upon movement of the diaphragm to the convex shape in response to an external stimuli, substantially all of the light is absorbed within the supporting housing with little or no light being reflected through the small aperture. The presence or absence of the light beam thus provides an indication of the external condition which may be a temperature value, pressure value or the like. The switch may also be utilized as a mechanical limit switch or a plurality of such optical switches may be fabricated to form a keyboard for entry of data into a computing system.

Abstract: A digital fiber optic sensor system utilizing a conventional n-track encoder system, but wherein the number of fiber optic paths to and from the sensor is reduced to one or two by utilizing the delay properties of optical fibers. These properties make it possible to divide a single short-duration optical pulse among several optical fibers of differing lengths to produce, at the far ends of the fibers, a like number of short-duration optical pulses essentially identical in shape and amplitude but spaced in time. Each of these fibers can be used to illuminate a different track of a multi-track optical encoder such that the tracks become sequentially interrogated by the time-spaced pulses. When the time-spaced responses are recombined, they form a serial binary word. In effect, a form of time-division multiplexing is achieved with the use of a minimum number of optical fiber elements.

Abstract: A light transmission load control system including a light responsive load controller for controlling a load setable in two states in response to optical impulses generated by an optical impulse generator. The optical impulse generator includes a light-emitting device for emitting optical impulses in response to electrical impulses produced by an electrical impulse generator. In its simplest form, the electrical impulse generator has a single moving part for controlling and indicating the state in which the load is set.

Abstract: Two fiberoptic cables are connected to a transparent hemiellipsoidal optical element at the foci thereof, at the back surface portion of the element. The fiberoptic cables are arranged so that their central axes, if continued into the element, would intersect approximately at the point of tangency on the curved front surface portion of the element with an imaginary plane parallel to the back surface portion. The geometry of the optical element is such that light entering the optical element through one fiberoptic cable is (1) substantially completely internally reflected in the optical element and exits through the other fiberoptic cable when the optical element is submerged in a first medium, and (2) substantially completely transmitted through the optical element into the surrounding medium when the element is in a second medium having a different index of refraction than the first medium.

Abstract: A method and apparatus for cutting an optical fiber along a plane that is either oblique or perpendicular to its axis. In principle, a predetermined portion of a fiber is held between a fixed holding fixture and a driven retaining fixture. The driven fixture is adapted to travel in an orbiting, spiraling path. A cutting device is mounted adjacent to the fiber portion and between the fixed and driven fixtures. Upon activation, the driven fixture orbits in a spiraling path and successively, the fiber will contact the cutting edge of the cutting device when the radius of the traveled orbit is equal to the radius of the cutting edge. This contact with the cutting edge causes the fiber to be scribed circumferentially in a plane either oblique or perpendicular to its axis depending on the mounting angle of the cutting device. Further spiraling of the driven fixture bends the fiber at the scribe and causes the fiber to snap or break in the plane of the scribe mark.

Abstract: To mechanically assist the suction action of a dredge head in dislodging particles embedded, e.g., on the ocean floor, a plurality of fingers extend downwardly from along the upper edge of an obliquely downwardly and forwardly facing nozzle opening. The fingers are resiliently connected to the nozzle and thus are capable of being bent downwardly so as to be juxtaposed across and thus temporarily block, the nozzle opening, whereby the intake of oversized particles is prevented.

Abstract: Apparatus for directing flow of water passing an ocean floor dredge head into a downwardly direction, and deflecting water from directly impinging upon the dredge nozzle body. The invention comprises a dredge vehicle chassis from which is pivotally suspended a dredge nozzle body and a water-flow deflecting shield, forwardly of the nozzle. Both the nozzle body and the shield are substantially vertically elongated members suspended substantially by the top of each element from the vehicle chassis.