Delphi Technologies, Inc.

Arcus Technology, Inc.

Aerial Imaging Corporation

Commissariat a L'energie Atomique

Université Louis Pasteur

Bernard Kress

Laurent Tupinier

Olivier R Marroux

Patrick Meyrueis

Walter Daschner

Mandiaye Ndao

Johann Michel

Paul-Antoine Tritschler

Barry Block

Christopher Chinho Chang

Arnold O Thornton

Patrice Twardowski

Jean-Paul Grandjean

Nandiaye Ndao

Lionel Ocard

Paul Antoine Tritschler

Johan Michel

An angle sensor for detecting an out-of-round condition includes a disc supporting angle coder rigidly attached to a rotating shaft and at least one fixed optical system including a coherent light source emitting a beam interfering with the angle coder of the support disc in order to code its angular position, a collimator of the said beam before interference and a photo detector of the modulated beam after interference. In one embodiment, two optical systems arranged 90&#xb0; from each other are employed. An alternative embodiment includes one optical system and the disc includes a circular track radially centred in at least one of its angular positions relative to the incident collimated light beam, and a radially orientated photo detector.

Out-of-round coder

An optical encoder and method for measuring displacement information using an optical encoder uses an encoder member with multiple digital diffractive optic regions to optically diffract an incident beam of light to produce output beams of light having intensity distribution patterns, which are used to generate electrical signals that provide relative displacement information of the encoder member.

Intensity-based optical encoder using digital diffractive optic regions

Optical rotation counter associated with a rotary disc of an angle sensor provided with means for coding the angular position of the disc, including at least one fixed source of coherent light emitting a light beam, a diaphragm and a support moved by the rotation of the coding disc. On its face facing the incident beam, the support includes at least one cell for coding its displacement orientated in the direction of the said displacement and generates an optical code by interference with the incident light beam, the said optical code being readable after interference on at least one photodetector.

Optical rotation counter

Device for detection of out-of-round on an angle sensor including a disc supporting angle coding means rigidly attached to a rotating shaft and at least one fixed optical system including a coherent light source emitting a beam interfering with the angle coding means of the support disc in order to code its angular position, means for collimation of the said beam before interference and a photodetector of the modulated beam after interference. In accordance with one possibility, it includes two optical systems arranged 90&#xb0; from each other. Alternatively, there is only one optical system and the disc includes a circular track radially centered in at least one of its angular positions relative to the incident collimated light beam, and a radially orientated photodetector.

An optical encoder uses an encoder member with one or more digital diffractive optic regions to optically manipulate an incident beam of light to extract relative displacement information of the encoder member.

Optical encoder with encoder member having one or more digital diffractive optic regions

A method for determining the position of one of two components in relative motion with respect to each other, using optical means, comprises:

Method for determining the position of a first moving component relatively to a second component and device for applying said method

A diffractive lens constructed in accordance with the invention comprises a set of bands such that the diffractive gratings in each band are modified. This is done to ensure that even if the lens is tilted (e.g. to prevent light from reflecting off the lens and, introducing distortion into an optical system), the lens continues to focus light onto a small point on a target surface. (The target surface is typically an optical or magneto-optic data recording medium.)

Diffractive lens with gratings modified to offset effects caused by holding the lens at an angle with respect to a light source

A magneto optic or optical disk drive comprises a laser source for providing laser beam, and a lens or compound lens for focussing the laser onto a currently inserted recording disk with specific overcoat thickness. In one embodiment, the lens is a compound lens that can focus aberration-free spots on different types of disk media having recording layers located under overcoats of different thicknesses. When a specific disk is inserted, only one spot in focussed onto the current recording layer. Furthermore, if the disk spins rapidly, it can wobble. The lens or compound lens comprises different regions where the focal length may vary slightly and continuously or discretely. Because of this, as the disk wobbles, the lens can nonetheless continue to focus laser light onto a small spot on the recording media, providing increased depth of focus in the vicinity of the currently inserted recording media. Furthermore, the increased depth of focus will also remedy problems related to the change in focal length of the lens with changes in wavelength of the laser source. Because some of these changes in wavelength occur abruptly, this is also a case in which the limited performance of the auto-focus tracking system would be overly burdened.

Dual focus lens with extended depth of focus

An optical device for focusing a light beam. The device includes a Fourier diffractive element that can separate an incident beam into n beams along n directions which are symmetric about an optical axis. The device also includes a diffractive element including n Fresnel lenses capable of refocusing the n beams onto the optical axis. The device may be used with lasers and laser cutting devices.

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Neubourg, France

Bernard Kress