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Digital holography device and phase shifting array

Foreign code F120007026
Posted date Nov 19, 2012
Country EPO
Application number 08851644
Gazette No. 2224291
Gazette No. 2224291
Date of filing Nov 21, 2008
Gazette Date Sep 1, 2010
Gazette Date Jun 29, 2016
International application number JP2008071246
International publication number WO2009066771
Date of international filing Nov 21, 2008
Date of international publication May 28, 2009
Priority data
  • 2008JP071246 (Nov 21, 2008) WO
  • P2007-303127 (Nov 22, 2007) JP
  • P2008-031965 (Feb 13, 2008) JP
Title Digital holography device and phase shifting array
Abstract DIGITAL HOLOGRAPHY DEVICE AND PHASE PLATE ARRAY Provided is a digital holography device (1) having a simple configuration and an improved image quality, including: a light source (4) that emits light, the light source being provided for supply of object light beams formed by radiation, transmission, scattering, reflection, or diffraction of the emitted light from a subject (6); an array device (2) that splits the light emitted from the light source (4) into two kinds of reference light beams having different phases in a plane perpendicular to a direction in which the light emitted from the light source (4) travels; a CCD camera (3) having an image-capturing plane (13) on which two kinds of interference fringe patterns are recorded, the interference fringe patterns being formed by interferences between the two kinds of reference light beams, which have been produced by the array device (2), and the object light beams, which have been formed by radiation, transmission, scattering, reflection, or diffraction from the subject (6); and an image reconstruction device that generates a reconstructed image of the subject (6) from the two kinds of interference fringe patterns recorded on the image-capturing plane (13).
Scope of claims [claim1]
1. A digital holography device comprising: a light source that emits light, wherein the emitted light comprises reference light and object light; a phase-shifting element that splits the reference light emitted from the light source into two kinds of reference light beams having different phases in a plane perpendicular to a direction in which the light emitted from the light source travels; image-capturing means having an image-capturing plane on which two kinds of interference fringe patterns are recorded, the interference fringe patterns being formed by interferences between the two kinds of reference light beams and an object light beam formed by radiation, transmission, scattering, reflection, or diffraction of object light from a subject; and an image reconstruction device that generates a reconstructed image of the subject according to the two kinds of interference fringe patterns recorded on the image-capturing plane, the device being characterized in that the phase-shifting element is an array device that has two kinds of phase-shifting regions arranged in a checkerboard pattern in the plane perpendicular to the direction in which the light emitted from the light source travels, the reference light beams having intensities that are higher than intensities of the object light beam.
[claim2]
2. The digital holography device according to claim 1, wherein
the image-capturing means is a CCD camera or a CMOS image sensor camera, and
the two kinds of regions are arranged to respectively correspond to pixels of the image-capturing means.
[claim3]
3. The digital holography device according to claim 1, wherein
the phase-shifting element splits the reference light into a first reference light beam having a phase that serves as a reference phase for phase shift measuring means and a second reference light beam that is out of phase with the first reference light beam in an amount of more than 0 and less than or equal to pi radians.
[claim4]
4. The digital holography device according to claim 1, wherein the light source emits linearly polarized light having first-direction polarized components and second-direction polarized components,
the digital holography device/ further comprises a polarization beam splitter that provides the object light having the first-direction polarized components, and provides reference light having the second-direction polarized components, and
the phase-shifting element has: a wavelength-plate optical-medium array device that splits the light beams having the second-direction polarized components into two kinds of reference light beams having different phases in a plane perpendicular to a direction in which the light beams having the second-direction polarized components travel; and a polarizer that transmits third-direction polarized light components of the object light beams and third-direction polarized light components of the two kinds of reference light beams.
[claim5]
5. The digital holography device according to claim 4, wherein
the phase-shifting element is integral with the image-capturing means.
[claim6]
6. The digital holography device according to claim 4, wherein
the wavelength-plate optical-medium array device has: optical media that transmit the light beams having the second-direction polarized components; and 1/4 wavelength plates that shift phases of the light beams having the second-direction polarized components and transmit the light beams thus phase-shifted.
  • Applicant
  • NATIONAL UNIVERSITY KYOTO INSTITUTE TECHNOLOGY
  • Inventor
  • AWATSUJI YASUHIRO
  • KANEKO ATSUSHI
  • KOYAMA TAKAMASA
  • TAHARA TATSUKI
  • WAKAMATSU TAKESHI
IPC(International Patent Classification)
Specified countries Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR
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