Projection system for measuring vibrations

Patent metadata

Field	Value
Publication number	US-10824112-B2
Application number	US-201816496889-A
Country	US
Kind code	B2
Filing date	Mar 19, 2018
Priority date	Mar 24, 2017
Publication date	Nov 3, 2020
Grant date	Nov 3, 2020

Abstract

Some embodiments are directed to a system for measuring vibrations of a surface of a mechanical part, by digital holography. The system includes a source of radiation emitting in a predetermined range of frequencies, a first separator element configured to define a first incident ray and a reference ray, a module for shaping a second incident ray from the first incident ray, and an optical element configured to make the reference ray and a radiation produced by a reflection of the incident ray on the surface of the mechanical part interfere. The module for shaping the second incident ray includes diffracting optical elements having a diffraction structure to diffract the incident radiation. The structure is from a polymer, sol-gel or photoresin material resting against a glass substrate, the structure including elements etched in a plane parallel and/or orthogonal to the substrate, with dimensions from 100 nanometres to 100 micrometres.

First claim

The invention claimed is:

1. A system for measuring vibrations of a surface of a mechanical part, by digital holography, the system comprising: a source of radiation emitting in a predetermined range of frequencies;
a first separator element configured to define a first incident ray and a reference ray;
a shaping module configured to produce a second incident ray from the first incident ray;
an optical element configured to make the reference ray and a radiation produced by a reflection of the second incident ray on the surface of the mechanical part interfere;
a camera configured to record a digital hologram in the form of the coherent summation of the reference ray and the radiation produced by said the reflection, wherein
the shaping module includes one or more diffracting optical elements, each having at least one diffraction structure configured to diffract all or part of the first incident ray,
the system being characterised in that the at least one diffraction structure is produced from a polymer, sol-gel or photoresin material resting against a glass substrate, the structure including elements etched in a plane parallel and/or orthogonal to the glass substrate, the elements having dimensions ranging from 100 nanometres to 100 micrometres.

Assignees

• Univ Du Mans
• Centre Nat Rech Scient
• Inst Mines Telecom Imt Atlantique Bretagne Pays De La Loire
• Inst De Rech Tech Jules Verne

Inventors

• Poittevin Julien
• Picart Pascal
• Heggarty Kevin
• Le Meur Julien

Classifications

• G03H1/0244

  Surface relief holograms (replicating hologram without interference recording G03H1/0276) · CPC title

• G03H1/0443

  Digital holography, i.e. recording holograms with digital recording means (holobject computation G03H1/0866) · CPC title

• G03H1/0005 Primary

  Adaptation of holography to specific applications (holographic optical element G02B5/32; holographic scanner G02B26/106; recognition using holographic mask G06V10/88; holographic memories G11B7/0065, G11C13/042) · CPC title

• G03H2223/23

  Diffractive element · CPC title

• G03H2270/22

  Disc shaped · CPC title