Sony Corporation

Sony Magnescale Inc.

Sony Magnescale Incorporation

Hiroyuki Ohkubo

Akihisa Narimatsu

Kenichi Sato

Yoshito Kato

Toshio Hashimoto

Hideki Tsuchiya

Hiroshi Maru

A hologram scale having a base substrate, a hologram film with a diffraction grating of a desired pitch exposed thereon, adhered to the base substrate, and with a protective substrate to protect the hologram film is manufactured by the following method: a hologram of a laser produced diffraction grating is formed on a holographic film to act as a scale. This film is applied on a central portion of a base substrate. Adhesives having moisture resistance are applied between the base and the protective substrates to essentially surround the hologram film positioned on the base substrate. The protective and the base substrates are sealed integrally by the adhesives, securing the hologram film therein so as to protect it from ambient environmental conditions.

Hologram scale having moisture resistance

A scaling device employs a first, outer cylinder, a longitudinal scale having detectable indicia thereon, and a second cylinder of lesser diameter than the first cylinder but of greater diameter than the radial extent of the scale. The cylinders and the longitudinal scale are disposed coaxially, with the scale affixed at one end thereof to an end cover plate in one end of the first cylinder. The second cylinder is journalled in a bearing in an end cover plate in the other end of the first cylinder for axial movement relative to the first cylinder over the longitudinal scale. A scale detector element is disposed at one end of the second cylinder to detect indicia on the scale and to generate scale signals in response to longitudinal relative displacement of the first and second cylinders. A third cylinder affixed to and disposed within the second cylinder defines an annulus between the second and third cylinders through which leads from the detector element can extend. A fitting can be provided for admitting pressurized air to the first cylinder. A spring and bearing arrangement can be used for centering the longitudinal scale relative to the cylinders.

Scaling device

A magnetic sensor for sensing the proximity of a magnetically permeable member, the sensor and member being relatively movable with respect to each other and having an axis of movement disposed within a fixed plane. The magnetic sensor includes two coplanar magnetoresistive elements, each element having a main current conducting path and possessing anisotropic resistance as a function of the direction of a resultant magnetic field applied thereto. The two magnetoresistive elements are connected in series, and a d.c. current is supplied to the series-connected elements. First and second saturating bias magnetic fields are supplied, as by a bias magnet, to respective ones of the magnetoresistive elements at the same angle .theta..sub.o to each of the respective main current conducting paths in the absence of the magnetically permeable member. The angle at which each bias field is supplied is changed by substantially equal and opposite small deviation angles .+-..DELTA..theta. in response to the relative movement of the permeable member proximate the magnetic sensor. An output circuit is coupled to the junction defined by the series-connected magnetoresistive elements to produce an output signal which varies as a function of the deviation angles by which the angles of the bias fields change.

Magnetic sensor with two series-connected magnetoresistive elements and

A magnetoresistive displacement sensing transducer employs a plurality of sensing elements consisting of magnetically biased magnetoresistive stripes. Each sensing element is operative to produce a signal in response to linear or rotational displacement with respect to a magnetic grating. The phases of the signals from the plurality of sensing elements are relatively displaced to permit determining direction of displacement and to increase accuracy through interpolation. A signal processing circuit uses the signals from the sensing elements and optionally their sums and differences to drive a reversible counter which is thereby updated to retain a value corresponding to the position of the transducer or the magnetic grating.

Magnetoresistive displacement sensor and signal reprocessing circuits

The magnetic field sensing apparatus includes first and second magnetoresistive elements having respective angularly disposed current path portions through which a bias current flows and to which a bias magnetic field is supplied. An external magnetic signal field is supplied from a magnetic source, and the magnetoresistive elements are relatively displaceable with respect to this source. The bias field is supplied at an angle of approximately 45.degree. with respect to the direction in which the bias current flows in each current path; and the source of external magnetic field generates a signal field whose polarity gradually decreases and then changes over to an opposite polarity at a boundary region. This change in the signal field is sensed by the magnetic sensor as it is relatively displaced, thereby producing an output signal that varies substantially linearly with this displacement over a predetermined range on both sides of the boundary region.

Displacement detector having first and second magnetoresistive elements

A length measuring device has a magnetic scale body including at least one origin signal magnetic section and a measurement signal magnetic section forming a magnetic grating, the magnetic scale body having a uniform frictional surface formed over the entire effective length of the scale body, and a detecting head body including an origin detecting head for detecting an origin signal and a measurement detecting head for detecting a measurement signal and provided with a scraper in elastic contact with the frictional surface of the magnetic scale body, the detecting head body moving relative to the magnetic scale of the body along the length of the latter.

Length measuring device

A magnetic sensor device utilizes the principle that the resistance of anisotropic magnetoresistive material is different in the case where the direction of current flowing in the material and the direction of a saturating magnetic field are parallel from the case where the direction of current and the direction of the saturating magnetic field are perpendicular to each other. The sensor device may be used to sense displacement and includes a ferromagnetic magnetoresistive element having at least one current path portion, a source applying electric current to each current path portion, and a magnetic field source producing first and second magnetic fields, occurring in first and second regions, and lying in first and second different mutually intersecting directions, respectively, with respect to the current path portion. The magnetoresistive element and the magnetic field source are displaceable in a predetermined direction relative to one another so that the relative amounts of the current path portion that are influenced by the first and second magnetic fields vary in accordance with such displacement. The magnetoresistive element can be connected to a constant current source, so that the voltage across the element indicates displacement. Alternatively, the magnetoresistive element can be formed of two series-connected current path portions, with a constant voltage source connected across both portions, so that the voltage appearing at the junction of the two current path portions indicates displacement.

Magnetoresistive displacement sensor arrangement

Apparatus is provided for sensing an external magnetic field. This apparatus is comprised of first and second coplanar magnetoresistive elements, each magnetoresistive element having a main current conducting path and also having anisotropic resistance as a function of the direction of the resultant magnetic field applied thereto. First and second equal bias magnetic fields are supplied to the first and second magnetoresistive elements, respectively, these bias magnetic fields being supplied at different angles with respect to their associated magnetoresistive elements. In one embodiment, the current conducting paths of the magnetoresistive elements are perpendicular to each other, and the respective bias magnetic fields extend in opposite directions, these directions being parallel to one of the main current conducting paths. In another embodiment, the main current conducting paths of the respective magnetoresistive elements extend in the same direction, and the respective bias magnetic fields are at an angle of, for example .+-.45.degree. to these main current conducting paths. The first and second magnetoresistive elements are connected in series with each other, and a d.c. current is supplied to this series connection. An output signal representing the magnitude of an external magnetic field as supplied to the magnetoresistive elements is derived from the junction formed by the series-connected elements.

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Chiba, Japan

Hiroyuki Ohkubo