Patents by Inventor Takashi Gemma

Takashi Gemma has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20190219451
    Abstract: A wavefront measuring device and method obtain wavefront information of an optical system. The method including: irradiating the optical system with a light beam; allowing the light beam passed via the optical system to come into a diffraction grating having periodicity in a first direction; and obtaining the wavefront information based on an interference fringe formed by light beams generated from the diffraction grating. The diffraction grating including: first portions which allow light to pass therethrough; and second portions which shield light, each of the second portions being provided between two of the first portions. A ratio between a width of one of the first portions in the first direction and a width of one of the second portions in the first direction is changed in the first direction, the one of the first portions and the one of the second portions being adjacent to each other.
    Type: Application
    Filed: March 26, 2019
    Publication date: July 18, 2019
    Inventors: Katsura OTAKI, Katsumi SUGISAKI, Takashi GEMMA
  • Patent number: 10288489
    Abstract: There is provided a wavefront measuring method for obtaining wavefront information of an optical system. The method including: irradiating the optical system with a light beam; allowing the light beam passed via the optical system to come into a diffraction grating having periodicity in a first direction; and obtaining the wavefront information based on an interference fringe formed by light beams generated from the diffraction grating. The diffraction grating including: first portions which allow light to pass therethrough; and second portions which shield light, each of the second portions being provided between two of the first portions. A ratio between a width of one of the first portions in the first direction and a width of one of the second portions in the first direction is changed in the first direction, the one of the first portions and the one of the second portions being adjacent to each other.
    Type: Grant
    Filed: May 29, 2013
    Date of Patent: May 14, 2019
    Assignee: NIKON CORPORATION
    Inventors: Katsura Otaki, Katsumi Sugisaki, Takashi Gemma
  • Publication number: 20150160073
    Abstract: There is provided a wavefront measuring method for obtaining wavefront information of an optical system. The method including: irradiating the optical system with a light beam; allowing the light beam passed via the optical system to come into a diffraction grating having periodicity in a first direction; and obtaining the wavefront information based on an interference fringe formed by light beams generated from the diffraction grating. The diffraction grating including: first portions which allow light to pass therethrough; and second portions which shield light, each of the second portions being provided between two of the first portions. A ratio between a width of one of the first portions in the first direction and a width of one of the second portions in the first direction is changed in the first direction, the one of the first portions and the one of the second portions being adjacent to each other.
    Type: Application
    Filed: May 29, 2013
    Publication date: June 11, 2015
    Inventors: Katsura Otaki, Katsumi Sugisaki, Takashi Gemma
  • Patent number: 7868997
    Abstract: In the inspection apparatus of this projection optical system, a folding glass member, comprising a flat surface part and a reflecting spherical surface part opposing to the flat surface part, is disposed on the image plane side of the projection optical system so that the flat surface part opposes to the projection optical system. Further, in a state wherein a liquid is supplied between the projection optical system and the folding glass member, a measuring beam emitted from an interferometer unit enters the projection optical system; the measuring beam that transmitted through the projection optical system and the liquid, and entered the folding glass member is reflected by the reflecting spherical surface part, and once again passes through the liquid and the projection optical system; and the interference fringes obtained from the measuring beam and the reference beam generated within the interferometer unit are detected.
    Type: Grant
    Filed: January 20, 2006
    Date of Patent: January 11, 2011
    Assignee: Nikon Corporation
    Inventors: Mikihiko Ishii, Yutaka Ichihara, Takashi Gemma
  • Patent number: 7843550
    Abstract: In the inspection apparatus of this projection optical system, a folding glass member, comprising a flat surface part and a reflecting spherical surface part opposing to the flat surface part, is disposed on the image plane side of the projection optical system so that the flat surface part opposes to the projection optical system. Further, in a state wherein a liquid is supplied between the projection optical system and the folding glass member, a measuring beam emitted from an interferometer unit enters the projection optical system; the measuring beam that transmitted through the projection optical system and the liquid, and entered the folding glass member is reflected by the reflecting spherical surface part, and once again passes through the liquid and the projection optical system; and the interference fringes obtained from the measuring beam and the reference beam generated within the interferometer unit are detected.
    Type: Grant
    Filed: December 1, 2006
    Date of Patent: November 30, 2010
    Assignee: Nikon Corporation
    Inventors: Mikihiko Ishii, Yutaka Ichihara, Takashi Gemma
  • Publication number: 20070076181
    Abstract: In the inspection apparatus of this projection optical system, a folding glass member, comprising a flat surface part and a reflecting spherical surface part opposing to the flat surface part, is disposed on the image plane side of the projection optical system so that the flat surface part opposes to the projection optical system. Further, in a state wherein a liquid is supplied between the projection optical system and the folding glass member, a measuring beam emitted from an interferometer unit enters the projection optical system; the measuring beam that transmitted through the projection optical system and the liquid, and entered the folding glass member is reflected by the reflecting spherical surface part, and once again passes through the liquid and the projection optical system; and the interference fringes obtained from the measuring beam and the reference beam generated within the interferometer unit are detected.
    Type: Application
    Filed: December 1, 2006
    Publication date: April 5, 2007
    Applicant: Nikon Corporation
    Inventors: Mikihiko Ishii, Yutaka Ichihara, Takashi Gemma
  • Publication number: 20060176457
    Abstract: In the inspection apparatus of this projection optical system, a folding glass member, comprising a flat surface part and a reflecting spherical surface part opposing to the flat surface part, is disposed on the image plane side of the projection optical system so that the flat surface part opposes to the projection optical system. Further, in a state wherein a liquid is supplied between the projection optical system and the folding glass member, a measuring beam emitted from an interferometer unit enters the projection optical system; the measuring beam that transmitted through the projection optical system and the liquid, and entered the folding glass member is reflected by the reflecting spherical surface part, and once again passes through the liquid and the projection optical system; and the interference fringes obtained from the measuring beam and the reference beam generated within the interferometer unit are detected.
    Type: Application
    Filed: January 20, 2006
    Publication date: August 10, 2006
    Applicant: Nikon Corporation
    Inventors: Mikihiko Ishii, Yutaka Ichihara, Takashi Gemma
  • Publication number: 20040036890
    Abstract: Methods are disclosed for measuring the surface profile of a “test surface” of an object such as an optical element, which can be a lens or reflective element (mirror). The “test surface” can have any of various profiles, including (but not limited to) spherical or aspherical. In a method embodiment, respective phase distributions of interference fringes, produced by interference of a reference light and light reflected from the test surface, and interference of the reference light and a respective light reflected from at a reference standard and/or a verification standard. A profile difference is computed from the respective phase distributions of interference fringes produced with respect to the test surface and the reference standard and/or verification standard.
    Type: Application
    Filed: November 13, 2001
    Publication date: February 26, 2004
    Applicant: Nikon Corporation
    Inventors: Shigeru Nakayama, Yuichi Takigawa, Takashi Gemma
  • Publication number: 20020191195
    Abstract: A method of manufacturing a projection optical system (37) for projecting a pattern from a reticle to a photosensitive substrate, comprising a surface-shape-measuring step wherein the shape of an optical test surface (38) of an optical element (36) which is a component in the projection optical system is measured by causing interference between light from the optical surface (38) and light from an aspheric reference surface (70) while the optical test surface (38) and said reference surface (70) are held in integral fashion in close mutual proximity. A wavefront-aberration-measuring step is included, wherein the optical element is assembled in the projection optical system and the wavefront aberration of the projection optical system is measured.
    Type: Application
    Filed: August 13, 2002
    Publication date: December 19, 2002
    Applicant: Nikon Corporation
    Inventors: Hiroshi Ichihara, Takashi Gemma, Shigerur Nakayama, Hajime Ichikawa
  • Patent number: 6456382
    Abstract: A method of manufacturing a projection optical system (37) for projecting a pattern from a reticle to a photosensitive substrate, comprising a surface-shape-measuring step wherein the shape of an optical test surface (38) of an optical element (36) which is a component in the projection optical system is measured by causing interference between light from the optical surface (38) and light from an aspheric reference surface (70) while the optical test surface (38) and said reference surface (70) are held in integral fashion in close mutual proximity. A wavefront-aberration-measuring step is included, wherein the optical element is assembled in the projection optical system and the wavefront aberration of the projection optical system is measured.
    Type: Grant
    Filed: June 1, 2001
    Date of Patent: September 24, 2002
    Assignee: Nikon Corporation
    Inventors: Hiroshi Ichihara, Takashi Gemma, Shigeru Nakayama, Hajime Ichikawa
  • Patent number: 6344898
    Abstract: Apparatus and methods are disclosed for measuring the surface topography of a test surface, such as a spherical or aspherical surface of a refractive or reflective optical element. The test surface is measured by detecting the state of interference fringes generated by interference of a reference light beam and a measurement light beam that interacts (e.g., reflects from) the test surface. The reference and measurement beams are produced by a point light source having a reflective surface. The point light source is disposed between a source of input light and the test surface. The measurement beam (after interacting with the test surface) and the reference beam are caused to interfere with each other to produce a first interference-fringe state. The distance between the point light source and the test surface can be changed between production of the first interference-fringe state and production of a second interference-fringe state.
    Type: Grant
    Filed: September 14, 1999
    Date of Patent: February 5, 2002
    Assignee: Nikon Corporation
    Inventors: Takashi Gemma, Hiroshi Ichihara, Hajime Ichikawa, Shigeru Nakayama, Bruce Jacobsen
  • Publication number: 20020012124
    Abstract: Apparatus and methods are disclosed for measuring a surface profile and/or a wavefront aberration of a target object. Exemplary target objects include mirrors, lenses, and lens systems. A representative apparatus configuration includes a light source, a light-flux optical system, a phase-state changing device, a detector, and a computer. The light-flux optical system (i) produces, from a light flux produced by the light source, measurement-light and reference-light fluxes, (ii) directs the measurement-light flux to the target object, (iii) provides the reference-light flux with a standard wavefront, and (iv) establishes interference between the two light fluxes. The phase-state changing device changes a phase state of the reference-light flux and/or the measurement-light flux relative to a respective standard. The detector detects interference fringes.
    Type: Application
    Filed: April 6, 2001
    Publication date: January 31, 2002
    Applicant: Nikon Corporation
    Inventors: Shigeru Nakayama, Yuichi Takigawa, Takashi Gemma
  • Publication number: 20010028462
    Abstract: A method of manufacturing a projection optical system (37) for projecting a pattern from a reticle to a photosensitive substrate, comprising a surface-shape-measuring step wherein the shape of an optical test surface (38) of an optical element (36) which is a component in the projection optical system is measured by causing interference between light from the optical surface (38) and light from an aspheric reference surface (70) while the optical test surface (38) and said reference surface (70) are held in integral fashion in close mutual proximity. A wavefront-aberration-measuring step is included, wherein the optical element is assembled in the projection optical system and the wavefront aberration of the projection optical system is measured.
    Type: Application
    Filed: June 1, 2001
    Publication date: October 11, 2001
    Applicant: NIKON CORPORATION
    Inventors: Hiroshi Ichihara, Takashi Gemma, Shigerur Nakayama, Hajime Ichikawa
  • Patent number: 6008904
    Abstract: Wavefront aberration-measuring apparatus are disclosed that can easily and accurately correct interference-fringe distortions arising from aberrations of an optical system in an interferometer and that can reduce wavefront aberration-measurement errors arising from such distortion. The apparatus comprise an interferometer that forms an interference fringe from a synthesis of a wavefront of light reflecting from a reference surface and a wavefront of light from a test object (such as a reflective surface or lens). The apparatus also comprises an image-pickup element for detecting the interference fringe, and an arithmetical calculator that calculates the wavefront aberration between the test object and the reference surface based on an output from the image-pickup element. Between the test object and the image-pickup element is an optical system (e.g., converging lens) that transmits a wavefront that is perpendicularly incident to a surface of the test object.
    Type: Grant
    Filed: September 17, 1997
    Date of Patent: December 28, 1999
    Assignee: Nikon Corporation
    Inventors: Mikihiko Ishii, Takashi Gemma, Katsuya Miyoshi
  • Patent number: 5898501
    Abstract: Apparatus and methods are disclosed for measuring wavefront aberrations microlithography projection lenses such as i-line or excimer laser projection lenses. The apparatus comprises an argon-ion laser irradiating a Fizeau surface that reflects reference light and transmits test light. The test light is reflected by a spherical reflecting surface to pass twice through the test lens and the Fizeau surface, to interfere with the reference light. A piezoelectric element changes the fringes slightly. An image-pickup device receives the interference fringes and outputs data to a processor that calculates corresponding wavefront aberrations of the test lens. For testing an i-line lens, the argon laser can be a single-mode, 363.8 nm laser. For testing a lens used with a KrF excimer laser, the argon laser can emit second-harmonic light at 248.25 nm.
    Type: Grant
    Filed: July 24, 1997
    Date of Patent: April 27, 1999
    Assignee: Nikon Corporation
    Inventors: Jun Suzuki, Takashi Gemma, Yutaka Ichihara
  • Patent number: 5563706
    Abstract: In an interferometer, reflected light from a reference surface and a subject surface are introduced to an imaging optical system through a beam splitter, and an interference fringe formed from light reflected from the both surfaces is observed with a detection optical system. An alignment optical member is disposed in an optical path between the imaging optical system and an image plane of the interference fringe such that the rear focal point of the alignment optical member is located at the image plane. The alignment optical member is inserted in the optical path in aligning the subject surface and is removed in measuring the interference fringe. Accurate alignment of the subject surface is easily attained. A beam expander is interposed between a polarizing beam splitter and the subject surface and a 90.degree. retarder is interposed between the beam expander and the subject surface. The 90.degree. retarder is constructed of one or a plurality of reflecting mirrors formed of dielectric multilayer films.
    Type: Grant
    Filed: August 22, 1994
    Date of Patent: October 8, 1996
    Assignee: Nikon Corporation
    Inventors: Masato Shibuya, Yutaka Ichihara, Takashi Gemma, Shuji Toyonaga, Keiji Inada
  • Patent number: 5561525
    Abstract: An interferometer is used for observing the shape of a surface to be detected with the desired spatial resolution. A variable aperture stop is arranged at a Fourier transform image plane of the surface to be detected within an imaging optical system for forming an interference pattern of a reference light and a measuring light. The aperture diameter of the variable aperture stop is adjusted by a control in accordance with the desired spatial resolution.
    Type: Grant
    Filed: December 20, 1995
    Date of Patent: October 1, 1996
    Assignee: Nikon Corporation
    Inventors: Shuji Toyonaga, Takashi Gemma
  • Patent number: 5504596
    Abstract: An exposure apparatus is used for reproducing a mask pattern of a semiconductor device or the like onto a photosensitive substrate using a holography. The holography is utilized also in a process for alignment between a mask pattern hologram and an exposure region of the substrate. The pattern hologram is recorded to a recording medium by interference between an object wave from the pattern and a reference wave, and a second hologram is formed to the medium by diffraction light from an alignment mark formed on the mask. Prior to reconstruction of the pattern image, reconstruction light from the second hologram, illuminated with a reconstruction wave, is irradiated onto the substrate arranged in place of the mask. A reproduction image of the alignment mark on the substrate surface illuminated with the reconstruction light is measured, and relative displacement between the medium and the substrate is detected from a result of the measurement.
    Type: Grant
    Filed: December 20, 1993
    Date of Patent: April 2, 1996
    Assignee: Nikon Corporation
    Inventors: Akihiro Goto, Takashi Gemma, Yutaka Ichihara, Nobutaka Magome, Naomasa Shiraishi, Hiroshi Shirasu, Toshio Matsuura
  • Patent number: 5039223
    Abstract: An interferometer for measuring an aspherical shape uses a computer generated hologram. The interferometer comprises a hologram disposed at each of positions conjugate with plural types of aspherical surfaces to be examined and filed lens means disposed between a position conjugate with a convex aspherical surfaces and another position with a concave aspherical surface. The interferometer can measure plural types of aspherical surfaces to be examined without need of changing the position of the interferometer for each of the aspherical surfaces to be examined, even if the number of different surfaces to be examined increases.
    Type: Grant
    Filed: July 10, 1989
    Date of Patent: August 13, 1991
    Assignee: Kabushiki Kaisha TOPCON
    Inventors: Takashi Gemma, Takuji Satoh, Takashi Yokokura
  • Patent number: 4848907
    Abstract: A method of analyzing interference fringes for use in a holographic interferometry process for measuring, by using a computer generated hologram, the shape of an object to be examined. The method comprises:a first step of obtaining a wave surface (xl, yl, zl) of a surface to be measured from measurement interference fringes;a second step of obtaining a coefficient A.sub.k relative to the wave surface (xl, yl, zl) of the surface, from a coefficient a.sub.ij of a series of the object wave which has been obtained based on the hypothesized coordinates on a computer hologram at the time when the computer generated hologram is made, and from a coefficient b.sub.ij of a series of the object based on the hypothesized coordinates on the object, the coefficient A.sub.k minimizing the square sum or the maximum value of a function of Xl, Yl, Zl, and a third step of obtaining a shape error from the ideal shape of the object by calculating the function on the basis of the A.sub.k.
    Type: Grant
    Filed: August 31, 1987
    Date of Patent: July 18, 1989
    Assignee: Tokyo Kogaku Kikai Kabushiki
    Inventors: Takashi Yokokura, Takashi Gemma, Satoh Takuji