Agency of Industrial Science and Technology

Ministry of International Trade & Industry

Kiyofumi Matsuda

Thomas H Barnes

Tomoaki Eiju

Naotake Ooyama

Shigeru Kokaji

Yuji Enomoto

Kazuhiro Honma

Koji Tenjinbayashi

Tsuguo Kohno

Yoshitaro Yoshida

Naoya Takeya

Tomoaki Eiji

A shearing interferometer measures the aberration of a lens by passing a beam through the lens, splitting the beam into plural beams with a slightly wedged plate and causing interference between the wavefronts of the beams. The front and rear optical surfaces of the wedged plate are coated with reflective thin films each having a specific reflectance and transmittance.

Shearing interferometer for measuring lens lateral aberration

A time series signal multichannel frequency analyzer comprises a Fourier transform lens, a liquid crystal panel disposed at the front focal plane of the Fourier transform lens, means for inputting a time signal from a different signal source to each scanning line of the liquid crystal panel, observation means disposed at the rear focal plane of the Fourier transform lens, and a cylindrical lens disposed between the Fourier transform lens and an observation plane of the observation means.

Time series signal multichannel frequency analyzer using liquid crystal

A high stability interferometer is capable of continuous measurement of small changes in the refractive index of a sample. The interferometer has a diffraction grating placed to be movable sideways or radially, and diffract laser light into beams which include +1, -1 and zero order beams. The diffraction grating is in the input plane of a Fourier Transform lens. The beams are brought to a focus in the output plane of the lens and are reflected back towards the lens by a mirror placed in the transform plane of the lens. The sample whose refractive index is to be measured is placed in the path of the +1 or -1 order beam, between the diffraction grating and the mirror.

High stability interferometer for measuring small changes in refractive

Optical spatial phase modulation is achieved by positioning a liquid crystal layer in the path of a light beam to be modulated and controlling the spatial distribution of refractive index of the liquid crystal layer by controlling the spatial distribution of the electrical field generated across the liquid crystal layer.

Method and device for achieving optical spatial phase modulation

A plurality of liquid crystal displays, each able to independently display one of a plurality of MRI tomograms, is dispersed such that the display screen of each appear planar from a common point and are positioned such that the spacing between each display screen and the next one in front or back and of it is proportional to the spacing between the cross sections belonging to the MRI tomograms displayed by those display screens. A hologram screen is provided in position facing the display screens of the plurality of displays. By illuminating the plurality of displays with light from behind, light passing through each of the display screens will impinge on the hologram screen, and part of this light will be diffracted backwards by the hologram screen, causing virtual images of the MRI tomograms to appear in front of the hologram screen.

Apparatus for three-dimensional viewing of magnetic resonance imaging

A device for the detection of the center of rotation of a rotating object under test comprises means for illuminating a laser beam on at least one position on the surface of the object thereby generating an interference fringe, means for subjecting the resultant reflected scattered laser beams to spectral analysis by the laser Doppler effect thereby finding the velocity of rotation of the position at which the interference fringe is formed on the surface, and means for determining the center of rotation on the basis of the velocity so found. Protection of the spectral analysis from the adverse effect of the pedestal component is accomplished by causing interference fringes to be formed at a plurality of positions on the surface of the object under test or by placing in the optical path for one of the pair of laser beams a prism capable of continuously modulating the laser frequency.

Device for detection of center of rotation of rotating object

A holographic straightness meter comprising an optical element and a hologram disposed on a moving member and one pair of reflection elements disposed on a fixed member. The object beam and reference beam from the optical element are reflected by the reflection elements so as to impinge upon the hologram and form interference fringes on the screen placed behind the hologram. The number, interval, and inclination of these interference fringes vary with the amount of lateral displacement of the moving member. Thus by analyzing the interference fringes for such factors, the amount of the lateral displacement of the moving member can be determined.

Holographic straightness meter

A laser Doppler velocimeter using two laser beams, when used for the measurement of the flow velocity of slow moving particles, fails to provide the measurement because the Doppler frequency and the pedestal component overlap on the power spectrum. This difficulty is eliminated by having a prism disposed in the path of one of the laser beams used. When this prism is continuously moved, the pedestal component and the Doppler frequency are separated from each other on the power spectrum, enabling the velocimeter to effect the measurement easily and accurately.

Laser doppler velocimeter

A transparent object can be converted into a visible image which is made up of a contrasted image of light and shade and therefore is readily perceivable with a three-dimensional illusion sensation by a method which comprises forming holograms with each of two collimated beams having slightly different angles of incidence and one reference beam, causing the reference beam to impinge upon the first hologram and thereby reproducing first order diffraction beams equivalent to the two collimated beams, then causing the reproduced diffraction beams to be passed through or reflected by the transparent object so as to impinge upon the second hologram and thereby reproducing diffraction beams laterally sheared and equivalent to the reference beam by which the second hologram was formed and imparting a suitable phase difference to these reproduced diffraction beams and thereby causing the beams to interfere with each other, whereby the phenomenon of interference thus produced on the surface of the object image gives rise to the visible image for desired observation.

Holographic shearing interference contrast method and interferometer

The sheared interference fringe of a wavefront from an object under test is obtained by recording on a first hologram the interference fringe formed between a first reference light beam and two light beams having slightly different angles of incidence with respect to the first hologram, recording on a second hologram the interference fringe formed between a second reference light beam and the two light beams reconstructed by an illuminating light beam incident on the first hologram from the same direction as the first reference light beam, placing the first and second holograms thus obtained at a prescribed distance from each other, causing a light beam from the object under test to impinge upon the first hologram from the same direction as the first reference light beam to produce light beams and projecting the produced light beams upon the second hologram for thereby causing the second hologram to produce light beams in the same direction as the second reference light beam.

Growing community of inventors

Tsukuba, Japan

Kiyofumi Matsuda