The invention concerns a dynamic sensor for sensing the distance and the position of a surface moving past said sensor, including: a send optical channel (3) emitting radiation (4) towards the surface (1) and two receive optical channels (5, 6) each receiving a portion (4A, 4B) of the radiation (4) reflected or diffusely reflected by said surface (1); a radiation emitter (2) coupled to the other end of the send optical channel (3); an opto-electronic converter (7, 8) coupled to the other end of each of the two receive optical channels (5, 6); a processor device (9) connected to the opto-electronic converters (7, 8); in accordance with the invention: the send optical channel (3) and the receive optical channels (5, 6) respectively have a send axis (3A) and receive axes (5A, 6A) that are parallel to each other; the ends of the optical channels (3, 5, 6) facing the surface (1) are in a common plane perpendicular to the axes (3A, 5A, 6A) of the optical channels (3, 5, 6), each of said ends constituting the vertex of a triangle in said plane, one side of the triangle running from the end of the send optical channel (3) having a length different than the length of the other side running from the end of the send optical channel (3)

Dynamic distance and position sensor and method of measuring the distance and the position of a surface using a sensor of this kind

A wear determination device for determining-vibration in a turbine engine component to reduce wear in a turbine engine. The wear determination device may be capable of measuring vibrations in a turbine engine component. The vibration measurement may be used to determine vibrations in a turbine engine to identify wear locations and sources of wear. The wear determination device may be configured such that multiple locations in a turbine engine may be monitored on a single turbine engine by moving the wear determination device from location to location.

Wear monitor for turbo-machine

Positional sensors receive light that has been reflected off a pair of complementary geometric patterns carried by a supporting, displaceable carrier surface. The sensors view the patterns through viewing windows as the carrier surface is displaced laterally, presenting differing portions of the patterns to the sensors. The patterns are shaped to produce outputs which, when their difference value is extracted, provide output signals that are a measure of the displacement of the carrier surface and in which common mode errors are minimized.

Differential displacement optical sensor

The present invention discloses an improved apparatus for performing safe and reliable built-in testing (BIT) of a laser initiated ordnance device. The system transmits light energy from a laser through optical fibers to achieve initiation of pyrotechnic or explosive charges and other ordnance. In the preferred embodiment, a separate BIT return fiber is included in the system in addition to the energy transmission fiber. The invention also incorporates a "telescope" comprising a pair of gradient-index (GRIN) rod lenses in series to first collimate and then reconcentrate light emitted by the energy transmitting fiber, while reflecting part of the light to an image at the face of the BIT fiber. Alternatively, an arrangement using a pair of aspheric silica lenses can be substituted for the GRIN lenses. The fraction of the light reflected to the BIT fiber can be controlled by specifying the reflectance at one of the lens end surfaces. The ratio of the output image size to the transmitting fiber core size (the magnification) can be controlled by appropriately selecting the focal lengths of the two lenses in the telescope. The invention also provides a simple means of making a spot size reduction (for example, from 100 microns down to 50 microns) without requiring alignment, and of adjusting the BIT amplitude response by adjusting the reflectance back from the second surface of the first lens. Because the combined pair of GRIN or other lenses has a magnification of less than unity, substantial power savings can also be achieved.

Dual fiber laser initiator and optical telescope

A distance measurement method includes imaging a first light source emitting a first wavelength, on a region of a substrate with a dispersive confocal lens; imaging a second light source emitting a second wavelength with the dispersive confocal lens on the region of the substrate; measuring intensity of light reflection emitted from the first light source; measuring intensity of light reflection emitted from the second light source; and generating a first response function wherein the first response function represents reflected light intensity emitted from the first light source as a function of the distance.

Coupled multi-wavelength confocal systems for distance measurements

An optical displacement sensor comprises first and second optical fibers which transmit light to and receive light reflected from first and second fixed reflectors. A third optical fiber transmits light to and receives light reflected from a moving reflector on the end of a core which moves in response to the displacement to be measured. The intensities of the light reflected to the fibers allows the displacement to be determined with immunity from variations such as in transmissivity and refractive index of a medium between the fibers and the reflectors.

Optical displacement sensor using dual reference reflectors

An optical displacement sensor suitable for use in drowned environments where the refractive index of a medium in the optical path may vary, comprises a light source emitting first to fourth wavelengths. The first and second wavelengths are within the infrared region of the spectrum, whereas the third and fourth wavelengths are in the visible region of the spectrum. A zone plate focuses the first and second wavelengths to respective positions substantially at the extremes of movement of a reflective element whose position is to be measured. The zone plate also focuses the third and fourth wavelengths to respective positions. A cold mirror is interposed between the zone plate and the reflective element and is arranged to transmit the first and second wavelengths and to reflect the third and fourth wavelengths. The ratio of the intensities of the light reflected from the cold mirror gives information about the refractive index of the medium in the optical path. This information can be used to correct the measurement of the position of the reflective element which is determined by the ratio of reflected intensities of the first and second wavelengths.

Optical displacement sensor employing reflected light of four wavelengths to determine displacement and the refractive index of the medium

A device and method for accurately sensing the direction and magnitude of small displacements between two objects, independent of the distance between the objects, utilizing a monochromatic light source and a reflector to produce a light standing wave pattern and a transparent photosensitive detector to detect the number of crests and/or nodes of the light standing wave pattern intercepted.

Stephen David Hawker

Papers

Optical displacement sensor using dual reference reflectors

Optical displacement sensor employing reflected light of four wavelengths to determine displacement and the refractive index of the medium

Optical displacement sensor.