Patents by Inventor Takeshi Yagi

Takeshi Yagi 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: 20040007722
    Abstract: In the present invention, a charge transfer unit is arranged on a first-plane side of a thinly-formed semiconductor base. Charge accumulating units are arranged on a second-plane side, the opposite side. A depletion prevention layer is arranged closer to the second-plane side than the charge accumulating units. The depletion prevention layer prevents a depletion region around the charge accumulating units from reaching the second plane of the semiconductor base. The depletion prevention layer can suppress surface dark current going into the charge accumulating units. Meanwhile, an energy ray incident from the second-plane side pass through the depletion prevention layer to generate signal charges in the charge accumulating units (depletion regions). The charge accumulating units collect, on a pixel-by-pixel basis, the signal charges which are to be transported to the charge transfer unit under voltage control or the like, and then are read to exterior as image signals.
    Type: Application
    Filed: July 11, 2003
    Publication date: January 15, 2004
    Inventors: Tadashi Narui, Keiichi Akagawa, Takeshi Yagi
  • Patent number: 6677178
    Abstract: Methods are disclosed for fabricating any of various semiconductor devices that include a reinforcing substrate bonded to a device substrate, wherein stresses between the two substrates are reduced compared to conventional devices. In the context of a back-surface-incidence (BSI) CCD light sensor, one or more pixels of a light-sensing array are formed on the surface of a “CCD” or “device” substrate. A layer of a curable resin adhesive is applied to the upper surface of the device substrate. A reinforcing substrate (e.g., glass) is placed on the layer of uncured adhesive, and the adhesive is cured. After curing the resin adhesive has a hardness of no greater than 40 (as measured by the JIS-A standard). With such an adhesive, when the resin adhesive cures, no stress is applied to the device substrate even a difference exists in the thermal expansion coefficients of the cured adhesive and the device substrate.
    Type: Grant
    Filed: March 13, 2001
    Date of Patent: January 13, 2004
    Assignee: Nikon Corporation
    Inventor: Takeshi Yagi
  • Patent number: 6671444
    Abstract: An optical fiber, capable of generating by means of nonlinear phenomena, white light in adequately broadened wavelength bands at both sides of a pumping optical pulse that is input, and stabilizing the polarized conditions. The fiber is formed by covering a core with a first cladding, and covering the first cladding with a second cladding, where the second cladding has a refractive index greater than that of the first cladding, but lower than that of the core. Stress-applying parts are provided inside the second cladding so as to sandwich the core from both sides to form a polarization-maintaining optical fiber. The shortest distance between the stress-applying parts is made 2.3 times or more the mode field diameter for the wavelength of the pumping optical pulse.
    Type: Grant
    Filed: May 21, 2001
    Date of Patent: December 30, 2003
    Assignee: The Furukawa Electric Co., Ltd.
    Inventors: Shinichi Arai, Takeshi Yagi, Kunihiko Mori, Hidehiko Takara, Satoki Kawanishi
  • Patent number: 6668121
    Abstract: There is provided an optical fiber for flattening a dispersion slope in a transmission wavelength band and suitable for high bit-rate and high capacity WDM transmission in a wide range. In this optical fiber, conditions of 0.8%≦&Dgr;1≦3.0%, −0.7%≦&Dgr;2≦−0.4%, and 0.2%≦&Dgr;3≦0.5% are satisfied when a relative refractive index difference of the first core with respect to the clad is set to &Dgr;1, a relative refractive index difference of the second core with respect to the clad is set to &Dgr;2, and a relative refractive index difference of the third core with respect to the clad is set to &Dgr;3. A cable cutoff wavelength lies on a short wavelength side from 1520 nm. Further, relations of S<0 and 0<(D/S)≦200 are satisfied in a specific set wavelength band having a range width of not less than 20 nm within a wavelength band of 1.5 &mgr;m when a chromatic dispersion at a specific wavelength within the wavelength band of 1.
    Type: Grant
    Filed: September 21, 2001
    Date of Patent: December 23, 2003
    Assignee: The Furukawa Electric Co., Ltd.
    Inventors: Ryuichi Sugizaki, Takeshi Yagi
  • Publication number: 20030210878
    Abstract: Optical fibers to form an optical transmission line suitable for WDM transmission in a wide-spreading wavelength band, having the following characteristics and parameters: a dispersion in absolute value of 0.5 ps/nm/km to 9 ps/nm/km in a wavelength band of 1430 nm to 1625 nm, a dispersion slope in absolute value of 0.04 ps/nm2/km or less at a wavelength of 1550 nm, a mode field diameter of 7 &mgr;m or less at a wavelength of 1550 nm and a cable cutoff wavelength of less than 1430 nm; core 11 surrounded by cladding 7, core 11 being at least two-layered (first layer 1 at the center and second layer 2 surrounding the first layer; relative refractive index of glass layer &Dgr;1 with reference to the cladding being adjusted to not less than 0.6 but not more than 1.6%, relative refractive index of second layer &Dgr;2 with reference to the cladding being adjusted to a negative value.
    Type: Application
    Filed: February 13, 2003
    Publication date: November 13, 2003
    Applicant: The Furukawa Electric Co., Ltd.
    Inventors: Naomi Kumano, Ryuichi Sugizaki, Kazunori Mukasa, Takeshi Yagi
  • Patent number: 6463201
    Abstract: A light amplification optical fiber capable of suppressing a decrease in an amplification efficiency thereof ascribed to the concentration quenching of erbium ions, and the nonlinearity thereof is provided. At least one rare earth element, for example, Yb, which is other than the erbium ions, and which has an ion radius not smaller than 70% and not larger than 130% of that of erbium ions is doped to a core portion of an erbium ion-doped light amplification optical fiber.
    Type: Grant
    Filed: November 5, 2001
    Date of Patent: October 8, 2002
    Assignee: The Furukawa Electric Co., Ltd.
    Inventors: Keiichi Aiso, Yoshio Tashiro, Takeshi Yagi
  • Publication number: 20020126973
    Abstract: The present invention provides an optical fiber having a compensation function of the dispersion characteristic of an optical transmission line in S-band, and preferably has a filter function for cutting off wavelengths exceeding S-band. The optical fiber of the present invention has three-layered glass layers having different compositions between neighboring layers. When the maximum relative refractive index difference of a first glass layer (1) formed at the innermost of the optical fiber to a third glass layer (3) (standard layer) is represented by &Dgr;1, and the minimum relative refractive index difference of a second glass layer (2) as a second layer from the innermost of the optical fiber to the standard layer is by &Dgr;2, the following inequalities are satisfied: 1.0%≦&Dgr;1≦3.0%, and −1.0%≦&Dgr;2≦−O.4%.
    Type: Application
    Filed: December 12, 2001
    Publication date: September 12, 2002
    Applicant: THE FURUKAWA ELECTRIC CO., LTD.
    Inventors: Ryuichi Sugizaki, Takeshi Yagi
  • Publication number: 20020122646
    Abstract: There is provided an optical fiber for flattening a dispersion slope in a transmission wavelength band and suitable for high bit-rate and high capacity WDM transmission in a wide range. In this optical fiber, conditions of 0.8%≦&Dgr;1≦3.0%, −0.7%≦&Dgr;2≦−0.4%, and 0.2%≦&Dgr;3≦0.5% are satisfied when a relative refractive index difference of the first core with respect to the clad is set to &Dgr;1, a relative refractive index difference of the second core with respect to the clad is set to &Dgr;2, and a relative refractive index difference of the third core with respect to the clad is set to &Dgr;3. A cable cutoff wavelength lies on a short wavelength side from 1520 nm. Further, relations of S<0 and 0<(D/S)≦200 are satisfied in a specific set wavelength band having a range width of not less than 20 nm within a wavelength band of 1.5 &mgr;m when a chromatic dispersion at a specific wavelength within the wavelength band of 1.
    Type: Application
    Filed: September 21, 2001
    Publication date: September 5, 2002
    Applicant: THE FURUKAWA ELECTRIC CO., LTD.
    Inventors: Ryuichi Sugizaki, Takeshi Yagi
  • Publication number: 20020114600
    Abstract: A light amplification optical fiber capable of suppressing a decrease in an amplification efficiency thereof ascribed to the concentration quenching of erbium ions, and the nonlinearity thereof is provided. At least one rare earth element, for example, Yb, which is other than the erbium ions, and which has an ion radius not smaller than 70% and not larger than 130% of that of erbium ions is doped to a core portion of an erbium ion-doped light amplification optical fiber.
    Type: Application
    Filed: November 5, 2001
    Publication date: August 22, 2002
    Applicant: THE FURUKAWA ELECTRIC CO., LTD.
    Inventors: Keiichi Aiso, Yoshio Tashiro, Takeshi Yagi
  • Publication number: 20020081716
    Abstract: A semiconductor device for detecting organic molecules is provided and affords higher sensitivity and better durability with respect to synthetic treatment of organic molecule probes. In one implementation, an organic molecule detecting semiconductor device 100 has pixels (including photoelectric converters) 110 disposed on a front (first main side) 101A of a silicon substrate 101, and recesses 112 in which DNA probes 161 are fixed are formed on a rear (second main side) 101B. Hence the bottoms of the recesses 112 serve as organic molecule probe disposition regions. The organic molecule detecting semiconductor device 100 constitutes a back-incident frame transfer (FT) type of CCD solid-state imaging device. In the analysis of DNA or other organic molecules, there is no need for the separate provision of an optical system for reading the light produced from a target (e.g., DNA of a specified structure). The overall apparatus is more compact and the manufacturing costs are reduced.
    Type: Application
    Filed: December 21, 2001
    Publication date: June 27, 2002
    Inventor: Takeshi Yagi
  • Publication number: 20010054723
    Abstract: In the present invention, a charge transfer unit is arranged on a first-plane side of a thinly-formed semiconductor base. Charge accumulating units are arranged on a second-plane side, the opposite side. A depletion prevention layer is arranged closer to the second-plane side than the charge accumulating units. The depletion prevention layer prevents a depletion region around the charge accumulating units from reaching the second plane of the semiconductor base. The depletion prevention layer can suppress surface dark current going into the charge accumulating units. Meanwhile, an energy ray incident from the second-plane side pass through the depletion prevention layer to generate signal charges in the charge accumulating units (depletion regions). The charge accumulating units collect, on a pixel-by-pixel basis, the signal charges which are to be transported to the charge transfer unit under voltage control or the like, and then are read to exterior as image signals.
    Type: Application
    Filed: July 18, 2001
    Publication date: December 27, 2001
    Inventors: Tadashi Narui, Keiichi Akagawa, Takeshi Yagi
  • Publication number: 20010026001
    Abstract: Methods are disclosed for fabricating any of various semiconductor devices that include a reinforcing substrate bonded to a device substrate, wherein stresses between the two substrates are reduced compared to conventional devices. In the context of a back-surface-incidence (BSI) CCD light sensor, one or more pixels of a light-sensing array are formed on the surface of a “CCD” or “device” substrate. A layer of a curable resin adhesive is applied to the upper surface of the device substrate. A reinforcing substrate (e.g., glass) is placed on the layer of uncured adhesive, and the adhesive is cured. After curing the resin adhesive has a hardness of no greater than 40 (as measured by the JIS-A standard). With such an adhesive, when the resin adhesive cures, no stress is applied to the device substrate even a difference exists in the thermal expansion coefficients of the cured adhesive and the device substrate.
    Type: Application
    Filed: March 13, 2001
    Publication date: October 4, 2001
    Applicant: Nikon Corporation
    Inventor: Takeshi Yagi
  • Patent number: 6074287
    Abstract: Polishing laps and apparatus incorporating such polishing laps for polishing workpieces such as semiconductor wafers are disclosed. The polishing laps are made from a cured mixture of an epoxy resin and a filler material, and preferably have at least a portion that is transparent to light. The polishing lap is preferably mounted on rigid polishing wheel or the like with or without an intervening layer such as an elastic layer. Polishing apparatus incorporating the polishing lap preferably include a light source for directing a beam of light toward the transparent portion of the polishing lap to enable the light beam to reflect from the working surface of the workpiece as the workpiece is being polished by the polishing lap. The apparatus also preferably includes a light detector for detecting light reflected from the surface of the workpiece.
    Type: Grant
    Filed: April 11, 1997
    Date of Patent: June 13, 2000
    Assignee: Nikon Corporation
    Inventors: Akira Miyaji, Takashi Arai, Takeshi Yagi
  • Patent number: 5899792
    Abstract: Optical polishing methods and apparatus are disclosed for polishing and planarizing surfaces of a wafer or other workpiece. A polishing apparatus according to the present invention preferably comprises a dispenser for dispensing polishing agent between a polishing body and the surface of the object to be polished. The polishing apparatus moves the polishing body and the object being polished against one another. The polishing body preferably comprises a light-permeable substance. A film-thickness measuring device for measuring the thickness of a film on the object being polished is preferably positioned on the side of the polishing body opposite of the surface of the object being polished. The film-thickness measuring device preferably measures the film thickness by using a light source to irradiate the object being polished through the polishing body. The film-thickness measuring device then uses light reflected from the film of the object being polished to determine the film's thickness.
    Type: Grant
    Filed: December 5, 1997
    Date of Patent: May 4, 1999
    Assignee: Nikon Corporation
    Inventor: Takeshi Yagi
  • Patent number: 5711903
    Abstract: The present invention provides a method of manufacturing a porous preform for an optical fiber, including the steps of removing impure particles from silica powder while being stirred in an alkaline liquid phase, and obtaining the porous preform for an optical fiber by applying the powder forming method to the silica powder used as a main raw material. The present invention further has a method of manufacturing a porous preform for an optical fiber, including the step of preparing a forming material by adding fine particles having a particle diameter satisfying the following formula (I) to the silica powder, and obtaining the porous preform by applying the powder forming method to the forming material: ##EQU1## wherein d: diameter of fine particles, and D: diameter of silica powder.
    Type: Grant
    Filed: August 14, 1996
    Date of Patent: January 27, 1998
    Assignee: The Furukawa Electric Co., Ltd.
    Inventors: Takeshi Yagi, Masato Oku, Takayuki Morikawa, Tsuguo Sato, Kazuaki Yoshida
  • Patent number: 5615295
    Abstract: A process for the production of an optical fiber a core which is elliptical in cross-section at one end and circular at the other end and which has little transmission loss and less of a reduction in the difference in indexes of refraction between the core and cladding, which consists of heating an optical fiber (1) having a core (c) having a uniform cross-sectional area in the longitudinal direction and a cladding (2) formed with at least one through hole (4A) along the longitudinal direction of the core while successively changing the heating temperature along the longitudinal direction of the optical fiber so as to continuously change the shape of the through hole, continuously change the cross-sectional shape of the core along the longitudinal direction of the optical fiber, and thereby make the cross-sectional shape of the core at one end of the optical fiber and the cross-sectional shape of the core at the other end different.
    Type: Grant
    Filed: September 13, 1995
    Date of Patent: March 25, 1997
    Assignee: The Furukawa Electric Co., Ltd.
    Inventors: Kazuaki Yoshida, Takayuki Morikawa, Takeshi Yagi
  • Patent number: 5352259
    Abstract: The present invention provides a method of manufacturing an optical fiber preform having the steps of disposing a rod member made of a silica-based material within a cavity of a mold, followed by loading a molding material within the mold cavity, and applying pressure to the mold from the outside to form a porous layer on the surface of the rod member and, thus, to obtain a porous preform, wherein at least one end portion of the rod member extends outside the mold cavity in the step of applying pressure to the mold. The particular method permits manufacturing a high quality porous preform free from splits or cracks, making it possible to obtain a high quality optical fiber preform free from residual bubbles.
    Type: Grant
    Filed: January 28, 1993
    Date of Patent: October 4, 1994
    Assignee: The Furukawa Electric Co., Ltd.
    Inventors: Masato Oku, Noritsugu Enomoto, Hiroshi Hihara, Tsuguo Sato, Kazuaki Yoshida, Takayuki Morikawa, Takeshi Yagi
  • Patent number: 5318432
    Abstract: An apparatus for forming a porous preform that is useable to an optical fiber by extruding a plastifiable material having silica powder as a main component thereof. The apparatus includes an extruding main body having a cylinder and a screw for extruding the plastifiable material from the cylinder and a material passage member connected to the cylinder so as to communicate therewith. The material passage member has a projection member which projects into the material passage member for preventing a lamination of the plastifiable material. The apparatus also includes a molding head connected to the material passage member so as to communicate therewith.
    Type: Grant
    Filed: August 25, 1992
    Date of Patent: June 7, 1994
    Assignee: The Furukawa Electric Co., Ltd.
    Inventors: Takeshi Yagi, Tsuguo Satou, Yoshiaki Koinuma, Kazuaki Yoshida
  • Patent number: 5314520
    Abstract: A method for manufacturing a preform having steps of obtaining a plastic material by kneading silica powder, a binder, water, and a surfactant, and obtaining a porous preform by extrusion-molding the plastic material.
    Type: Grant
    Filed: February 9, 1993
    Date of Patent: May 24, 1994
    Assignee: The Furukawa Electric Co., Ltd.
    Inventors: Takeshi Yagi, Tsuguo Satoh, Yoshiaki Koinuma, Kazuaki Yoshida
  • Patent number: 5244485
    Abstract: The method of manufacturing a silica glass preform comprises the steps of inserting a rod-like member mainly containing a ductile material, into a forming space of a mold, charging the remaining space of the forming space with a forming material containing silica glass powder or doped silica glass powder, compressing the mold charged with the forming material from outside such as to form a porous glass body of the forming material around the rod-like member, removing the rod-like member from the porous glass body, inserting a glass rod into the hole formed after removal of the rod-like member, purifying said porous glass body in which the glass rod is inserted, and consolidating said porous glass body purified in the above purifying step.
    Type: Grant
    Filed: April 24, 1992
    Date of Patent: September 14, 1993
    Assignee: The Furukawa Electric Co., Ltd.
    Inventors: Hiroshi Hihara, Masato Oku, Takeshi Yagi, Noritsugu Enomoto, Tsuguo Sato, Kazuaki Yoshida, Takayuki Morikawa