Fujinon Corporation

Fuji Photo Optical Co., Ltd.

Fujifilm Corporation

Zongtao Ge

Takayuki Saito

Kunihiko Tanaka

Hideo Kanda

Noboru Koizumi

Fumio Kobayashi

Kenichi Takahashi

Ping Sun

Minoru Kurose

Seiji Mochitate

The relative position of a test surface is sequentially changed from a reference position where a surface central axis is aligned with a measurement optical axis such that the measurement optical axis is sequentially moved to a plurality of annular regions obtained by dividing the test surface in a diametric direction. The test surface is rotated on a rotation axis whenever the relative position is changed. Measurement light composed of a plane wave is radiated to the rotating test surface, and a one-dimensional image sensor captures interference fringes at each of a plurality of rotational positions. The shape information of each annular region is calculated on the basis of the captured interference fringes at each rotational position, and the shape information is connected to calculate the shape information of the entire measurement region.

Optical wave interference measuring apparatus

The relative position of a test surface is sequentially changed from a reference position where a surface central axis is aligned with a measurement optical axis such that the measurement optical axis is sequentially moved to a plurality of annular regions obtained by dividing the test surface in a diametric direction. The test surface is rotated on a rotation axis whenever the relative position is changed. Measurement light that travels while being converged by a Mirau objective interference optical system is radiated to the rotating test surface, and a one-dimensional image sensor captures interference fringes at each of a plurality of rotational positions. The shape information of each annular region is calculated on the basis of the captured interference fringes at each rotational position, and the shape information is connected to calculate the shape information of the entire measurement region.

The light wave interferometer apparatus is provided and includes: a luminous flux, which is sent from the light source and divided into two portions by the luminous flux separation and composition unit, are combined with each other again under the condition that the divided luminous fluxes hold wavefront information corresponding to the surface shapes of the aspherical lens to be inspected and the reference aspherical lens by the respectively corresponding basis spherical lenses. Therefore, a wavefront difference of the aspherical lens to be inspected with respect to the reference aspherical lens is made to be interference fringe information and formed on an image pickup plane of the interferometer CCD camera. The basis spherical lenses have the basis spherical surfaces, the curvatures of which are equal to each other.

Light wave interferometer apparatus

An optical element to be measured is irradiated with the light which has passed through an indicator, thereby to form an indicator image on an image pick-up surface. Maximum peak coordinates are specified and stored as a position of the indicator image relating to the first surface. Whether the second largest peak may be specified or not is determined. In case that this result is NO, the maximum peak indicator image is deleted, and maximum peak coordinates are specified again and stored as a position of the indicator image relating to the second surface.

Method of measuring amount of eccentricity

A wavefront measuring apparatus for optical pickup includes: a beam splitting section; a wavefront shaping section; a beam combining section that generate interference light; an interference fringe image-acquiring section that acquires an interference fringe image including wavefront information of the light beam; and an analyzing section that analyzes a wavefront of the light beam on the basis of the interference fringe image. The analyzing section includes: an image processing section that performs a filtering process on the interference fringe image to eliminate a frequency component corresponding to the sub beam, so as to acquire the filtering-processed interference fringe image, and a wavefront analyzing section that analyzes a wavefront of the main beam on the basis of the filtering-processed interference fringe image.

Wavefront measuring apparatus for optical pickup

The light beam measurement apparatus comprises a beam splitter that divides a light beam emitted from a light source unit into two luminous fluxes, a semi-transmitting/reflecting surface that reflects part of one of the divided luminous fluxes back in the opposite direction to the direction of incidence as a sample luminous flux, and reflection-type reference light producing means that converts part of the luminous flux transmitted through the semi-transmitting/reflecting surface into a wavefront-shaped reference luminous flux and outputs this reference luminous flux; this light beam measurement apparatus can carry out both wavefront measurement and light beam spot characteristic measurement on a light beam simultaneously.

Wavefront-measuring interferometer apparatus, and light beam measurement apparatus and method thereof

A sample inclination measuring method rotates, by a predetermined angle with respect to an interferometer apparatus, a columnar member having a leading end face in a planar form while the columnar member is held by a clamping apparatus, detects a relative angle between a reference surface of the interferometer apparatus and the leading end face at each of two rotational positions, and measures the inclination of the axis of the columnar member by using a predetermined arithmetic expression according to thus detected two angles.

Sample inclination measuring method

In a low coherent interference fringe analysis method, a light intensity distribution of interference fringes formed by object light and reference light in a sample is represented by a light intensity distribution function using an envelope function. Subsequently, phase shifting is carried out, so as to measure the light intensity at each shift stage. According to thus measured light intensities at respective shift stages, unknowns of the light intensity distribution function are computed. Then, according to the computed unknowns, a peak position of a curve of the envelope function is determined. According to thus determined peak position, phase information of the sample is determined.

Low coherent interference fringe analysis method

A circular region extracting method captures onto a coordinate system a fringe image of a sample having a circular region to be analyzed within an area to be observed, binary-codes the fringe image of the area by a fringe analysis method on the coordinate system, places a plurality of linear gratings in parallel with each other with a predetermined interval on thus binary-coded coordinate system, and uses the linear gratings so as to extract a circular image region representing the region to be analyzed on the coordinate system.

Method of extracting circular region from fringe image

While a ferrule held by a clamping apparatus is rotated by a predetermined angle, respective interference fringe images of a spherical leading end part of the ferrule are obtained at three or more rotational positions. Respective interference fringe center positions are obtained in thus obtained three or more interference fringe images. The center position of a circle passing near each of the interference fringe center positions is calculated and defined as a measured center position. Relative distance information between the measured center position and a position corresponding to the rotational center position of the spherical leading end part of the ferrule or the relative distance information and relative directional information thereof are outputted as an inclination error adjustment value for the axis of the ferrule.

Method of assisting sample inclination error adjustment

A phase shift fringe image analysis method comprises the steps of shifting an object to be observed and a reference relative to each other by using a phase shift device, obtaining fringe image data at three or more phase shift positions having a given phase gap therebetween, and determining a phase of the object by analyzing thus obtained plurality of fringe image data items. The positional data of at least three phase positions are specified, and the whole or part of the fringe image data on which carrier fringes at these phase positions are superposed is subjected to a predetermined arithmetic operation so as to carry out a phase analysis and determine the phase of the object.

Phase shift fringe analysis method and apparatus using the same

In a fringe analysis method comprising the step of subjecting fringe image data carrying wavefront information of an object to be observed to Fourier transform method so as to determine a wavefront of the object, the fringe image data is multiplied by a window function corresponding to an effective data area of the fringe image data before the Fourier transform method is applied to.

Fringe analysis method using fourier transform

A method of detecting a posture of an object comprises the steps of acquiring fringe image data carrying phase information of the object; subjecting the whole or part of fringe image data to arithmetic processing using Fourier transform so as to determine a tilt frequency of a fringe corresponding to an inclination of the object in the fringe image data; and detecting the inclination of the object according to the tilt frequency.

Method of detecting posture of object and apparatus using the same

When analyzing the fringe pattern of an object to be observed by using Fourier transform method with respect to closed interference fringe image data, the original data expressed by an orthogonal coordinate system are once converted into fringe image data represented by a polar coordinate system, the converted data are analyzed by the conventional Fourier transform method, and then the resulted data are converted back into the original orthogonal coordinate system by inverse coordinate transformation, so as to obtain the wavefront corresponding to the original wavefront to be observed.

In a fringe analysis method using Fourier transform, fringe image data is determined in a state where a wavefront from an object and a wavefront from a reference are relatively inclined with respect to each other by a minute amount, and a carrier fringe occurring due to this inclination is superposed on a fringe occurring due to wavefront information of the object. The inclination is set such that the carrier frequency occurring due to the inclination is a predetermined multiple of the basic frequency determined by the wavefront information of the object and observing means.

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Saitama, Japan

Zongtao Ge