Image Pickup Tube Patents (Class 313/365)
  • Patent number: 10481280
    Abstract: A radiation detecting apparatus includes a scintillator, a pixel array in which a plurality of pixels that each converts visible light converted by the scintillator into electric signals is arranged in a two-dimensional array form on a first surface of a substrate, a plurality of connection terminal portions arranged on a periphery of the pixel array on the first surface of the substrate, and a conductive member to which a constant potential is supplied, wherein the conductive member, the pixel array, and the scintillator are arranged in this order from a side irradiated with radiation, and the scintillator is arranged on a first surface side, and wherein the conductive member is arranged in a region of a second surface opposite to the first surface of the substrate except for a region opposite to the plurality of connection terminal portions.
    Type: Grant
    Filed: June 27, 2017
    Date of Patent: November 19, 2019
    Assignee: Canon Kabushiki Kaisha
    Inventors: Tomoaki Ichimura, Youjirou Hiratsuka
  • Patent number: 10408579
    Abstract: A one man portable electronic pulse generator includes a standard rifle having a muzzle and capable of firing a blank cartridge containing propellant. A blank firing adapter is fixed to the muzzle of the rifle. A piezoelectric generator is aligned with the gas exit orifice of the blank firing adapter. A lead cable is electrically connected from the piezoelectric generator to a unit in series with said lead cable for storing or utilizing said electronic pulse.
    Type: Grant
    Filed: September 25, 2018
    Date of Patent: September 10, 2019
    Assignee: The United States of America as Represented by the Secretary of the Army
    Inventors: Adam L. Foltz, James E. Burke
  • Patent number: 10180309
    Abstract: A one man portable electromagnetic pulse transmitter includes a standard rifle having a muzzle and capable of firing a blank cartridge containing propellant. A blank firing adapter is fixed to the muzzle of the rifle. A piezolectric generator is aligned with the gas exit orifice of the blank firing adapter. An antenna is electrically connected to the piezolectric generator and an electromagnetic shield is disposed between the antenna and the piezolectric generator.
    Type: Grant
    Filed: July 8, 2016
    Date of Patent: January 15, 2019
    Assignee: The United States of America as Represented by the Secretary of the Army
    Inventor: James E. Burke
  • Patent number: 9524439
    Abstract: A monitoring unit for the exterior in the direction of travel of a motor vehicle includes at least one camera system with an image recording sensor. The sensor has color encoding in some regions and, otherwise, monochrome encoding. An assist system is also provided with such a monitoring unit, in particular a traffic sign and/or lane recognition assist system.
    Type: Grant
    Filed: May 6, 2005
    Date of Patent: December 20, 2016
    Assignee: Continental Automotive GmbH
    Inventors: Henryk Frenzel, Thorsten Köhler, Stephan Voltz, Ulrich Wagner
  • Publication number: 20110038465
    Abstract: Systems and methods are provided for field emission device. An array of carbon nanotubes is arranged in a variable height distribution over a cathode substrate. An anode is provided to accelerate the emitted electrons toward an x-ray plate. Voltage is supplied across the array of carbon nanotubes to cause emission of electrons. The pointed height distribution may be linear or parabolic, and a peak height of the variable height distribution may occur in a center of the array. A side gate may also be provided adjacent the array of carbon nanotubes to provide improved electron emission and focusing control.
    Type: Application
    Filed: November 18, 2009
    Publication date: February 17, 2011
    Applicant: INDIAN INSTITUTE OF SCIENCE
    Inventor: Debiprosad Roy Mahapatra
  • Patent number: 7876033
    Abstract: An electron tube of the present invention includes: a vacuum vessel including a stem portion made of quartz and formed with an opening; a lid portion connected to the stem portion via a joining member made of aluminum so as to seal the opening, having a recess portion depressed to a vacuum side in the opening, and made of Kovar; a voltage applying section arranged in the vacuum vessel; and wiring for electrically connecting the voltage applying section and the lid portion.
    Type: Grant
    Filed: October 23, 2008
    Date of Patent: January 25, 2011
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Tomohiro Ishizu, Yasuyuki Egawa, Atsuhito Fukasawa, Motohiro Suyama
  • Patent number: 7777196
    Abstract: An electron emitter for a display provides an electron source, an electron accelerator, an electron collector disposed between the electron source and the electron accelerator, and one or more electron deflectors to selectively deflect electrons in an electron beam or electron plane towards the electron collector phosphorous coating on a display screen, within a non-metallic vacuum chamber having an adjustable vacuum. Pinhead electrode electron deflectors may each control one color of a pixel, and each set of three adjacent pinhead electrodes may comprise a complete pixel on the display screen.
    Type: Grant
    Filed: June 12, 2008
    Date of Patent: August 17, 2010
    Inventor: Wesam Khalil
  • Patent number: 6828721
    Abstract: Disclosed is an image display comprising: a substrate including a light function layer for displaying an image by emitting or blocking light in accordance with a supplied voltage; and a frame body for surrounding the substrate, wherein a concave portion is provided on a side surface of the substrate, a convex portion is provided on an inner side of a side surface of the frame body, and the convex portion is fitted to the concave portion.
    Type: Grant
    Filed: February 27, 2002
    Date of Patent: December 7, 2004
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Naohide Wakita
  • Publication number: 20020008454
    Abstract: Disclosed is an electron source forming substrate provided with an insulating material layer provided on the surface of a substrate, at which surface an electron-emitting device is disposed, wherein the insulating material layer has a plurality of partially exposed metal oxide particles on its surface. Also disclosed are an electron source including a substrate and an electron-emitting device arranged on the substrate, wherein the substrate is an electron source forming substrate as described above, and an image display apparatus including an envelope, an electron-emitting device arranged in the envelope, and an image display member adapted to display images through application of electrons from the electron-emitting device, wherein a substrate on which the electron-emitting device is arranged is an electron source forming substrate as described above.
    Type: Application
    Filed: May 2, 2001
    Publication date: January 24, 2002
    Inventors: Kazuya Ishiwata, Shuji Yamada, Tadayasu Meguro
  • Patent number: 6320303
    Abstract: The object of the present invention is to provide a radioactive-ray image tube having less deformations, such as the twist of an input substrate, less aberration over the entire regions of an output image, excellent resolution and good brightness uniformity and contrast characteristics. This radioactive-ray image tube 1a comprises an input window 10 formed on one side surface of a vacuum vessel 2a and allowing radioactive-rays to enter the vacuum vessel 2a, an input screen 5 for converting the radioactive-rays incident on the input window 10 into a fluorescent image or a photoelectric image, and an input substrate 4a holding the input screen 5, is characterized in that the input substrate 4a comprises of a clad material 13 having an aluminum alloy material 11 on the radioactive-ray incidence side and a pure aluminum material 12 on the input screen 5 side provided integrally with each other.
    Type: Grant
    Filed: November 20, 1998
    Date of Patent: November 20, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takashi Noji, Mitsumasa Hiroi, Junji Taniguchi, Yoshinobu Sekijima
  • Patent number: 6052432
    Abstract: An x-ray image intensifier includes a photoconductive x-ray detector having an electro-optic light modulator disposed on a photoconductive detector layer. The photoconductive x-ray detector absorbs x-rays passing through an object to be imaged to form an x-ray exposure of the object. An optical image of the x-ray exposure is generated when light passes through the photoconductive x-ray detector. An imager captures optical images of the x-ray exposures. A processor coupled to the imager digitizes and stores the optical images of the x-ray exposure captured by the imager at selected intervals.
    Type: Grant
    Filed: December 7, 1998
    Date of Patent: April 18, 2000
    Assignee: Sunnybrook Hospital
    Inventors: Pia-Krista M. Rieppo, John A. Rowlands
  • Patent number: 5847499
    Abstract: An x-ray image intensifier includes a photoconductive x-ray detector having an electro-optic light modulator disposed on a photoconductive detector layer. The photoconductive x-ray detector absorbs x-rays passing through an object to be imaged to form an x-ray exposure of the object. An optical image of the x-ray exposure is generated when light passes through the photoconductive x-ray detector. An imager captures optical images of the x-ray exposure. A processor coupled to the imager digitizes and stores the optical images of the x-ray exposure captured by the imager at selected intervals.
    Type: Grant
    Filed: January 31, 1997
    Date of Patent: December 8, 1998
    Assignee: Sunnybrook Hospital
    Inventors: Pia-Krista M. Rieppo, John A. Rowlands
  • Patent number: 5828166
    Abstract: An intensifying system adapted to be affixed to an electronic imaging device such as a single lens reflex camera or a video camera. The system includes a central intensifying unit for intensifying an image at lower light levels. A back body adapter and a front lens adapter would combine with the central intensifying unit and would be attached to the body of the camera. An electronic objective lens which is normally attached to the camera, would be removed and would be affixed to the front lens adapter.
    Type: Grant
    Filed: September 11, 1996
    Date of Patent: October 27, 1998
    Assignee: Electrophysics Corp.
    Inventors: Michael Roselli, Frank Vallese, Gerard DiTaranto, Robert Lindner
  • Patent number: 5825435
    Abstract: By selecting the number of apertures per vertical row in the shadow mask of a color cathode ray tube to be in the range between 615 and 650, such a cathode ray tube can be used both in a PAL, an NTSC system and a MUSE system without the occurrence of disturbing Moire effects. In a second embodiment the number of apertures per row ranges between 425 and 450.
    Type: Grant
    Filed: August 31, 1995
    Date of Patent: October 20, 1998
    Assignee: U.S. Philips Corporation
    Inventors: Leendert Vriens, Rene A. Stoffels
  • Patent number: 5757118
    Abstract: In an X-ray image intensifier tube apparatus inc-luding a cylindrical magnetic shield placed to surround the outer periphery of an X-ray image intensifier tube, a ferromagnetic thin plate is placed in front of a convex input window of a vacuum envelope and a correcting magnetic coil is placed inside the cylindrical magnetic shield to surround the input window. This structure allows an output image which is substantially free of distortion to be obtained.
    Type: Grant
    Filed: May 17, 1996
    Date of Patent: May 26, 1998
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Hiroshi Kubo
  • Patent number: 5747826
    Abstract: The present invention provides a photoemission device excellent in quantum efficiency of photoelectric conversion, a high-sensitive electron tube employing it, and a high-sensitive photodetecting apparatus. A photoemission device of the present invention is arranged to have a photon absorbing layer for absorbing incident photons to excite photoelectrons, an insulator layer layered on one surface of the photon absorbing layer, a lead electrode layered on the insulator layer, and a contact formed on the other surface of the photon absorbing layer to apply a predetermined polarity voltage between the lead electrode and the other surface of the photon absorbing layer, whereby the photoelectrons excited by the incident photons entering the photon absorbing layer and moving toward the one side are made to be emitted by an electric field formed between the lead electrode and the one surface by the predetermined polarity voltage.
    Type: Grant
    Filed: June 27, 1996
    Date of Patent: May 5, 1998
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Minoru Niigaki, Toru Hirohata, Tuneo Ihara, Masami Yamada
  • Patent number: 5742115
    Abstract: A color image intensifier device includes an evacuated envelope with an input window for receiving incident light from the environment. A photocathode is deposited upon the interior surface of the envelope of the input window for converting the incident light into a photoelectron signal. A phosphor layer, emitting several wavelengths approximating white light when struck by and amplified by an intensified photoelectron signal, is deposited upon an interior surface of the envelope proximate an output window to convert the amplified signal into a visible light output image projected from the intensifier.
    Type: Grant
    Filed: June 14, 1996
    Date of Patent: April 21, 1998
    Assignee: Orlil Ltd.
    Inventor: Michael Gertsenshteyn
  • Patent number: 5646477
    Abstract: An X-ray image intensifier that includes a vacuum envelope having a metal X-ray input window and an input screen formed on the inner surface of the X-ray input window, a focusing electrode, an anode, and an output screen arranged in the vacuum envelope along the traveling direction of electrons generated from the input screen. The X-ray input window has a rough, surface-hardened layer on the side on which the input screen is formed. The input screen includes a phosphor layer adjacent to the rough, surface-hardened layer and a photocathode formed on the phosphor layer.
    Type: Grant
    Filed: October 4, 1996
    Date of Patent: July 8, 1997
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Shirofumi Yamagishi
  • Patent number: 5369267
    Abstract: A low cost image intensifier tube is provided which has an improved vacuum sealing mechanism and improved optical transmission. Glass windows on both the input and output of the tube are vacuum sealed within the housing by a ring of indium that contacts the interface between each of the windows and the housing. A pair of raised pointed flanges each positioned along the inner housing surface interfacing the windows protrude into the adjacent ring of indium for improving the vacuum seal of both input and output windows and for controlling the spacing of the elements within the tube. Sealing the photocathode from the rest of the tube is a ceramic cathode cork. The cathode cork is a solid sealing ring press fit within the tube housing and colocated between the input window at the outer edge of the photocathode and the microchannel plate.
    Type: Grant
    Filed: May 18, 1993
    Date of Patent: November 29, 1994
    Assignee: Intevac, Inc.
    Inventors: David B. Johnson, Allan W. Scott, Stephen J. Bartz
  • Patent number: 5200250
    Abstract: A phosphor comprising phosphor particles and a surface treating material attached or coated on the phosphor particles, wherein said surface treating material comprises zinc and a polycarboxylic acid.
    Type: Grant
    Filed: October 19, 1990
    Date of Patent: April 6, 1993
    Assignee: Kasei Optonix, Ltd.
    Inventors: Hideo Tono, Kazuhito Iwasaki
  • Patent number: 5017828
    Abstract: An improved image sensor made of photosensitive semiconductor materials with a number of pixels each including an n-type semiconductor layer, a p-type semiconductor layer and an intrinsic semiconductor layer disposed between the n-type and p-type layers. The n-type and p-type layers are made from a semiconductor material having a high resistivity. The high resistivity of the n-type layer and the p-type layer functions to prevent crosstalk currents from passing between the pixels.
    Type: Grant
    Filed: April 25, 1989
    Date of Patent: May 21, 1991
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Takeshi Fukada, Mitsunori Sakama, Nobumitsu Amachi, Naoya Sakamoto, Mitsufumi Codama, Toru Takayama
  • Patent number: 4719439
    Abstract: A thermal saddle for a camera tube deflection yoke which dissipates heat from the camera tube and deflection yoke to enable the use of maximum operating voltages on the camera tube for enhanced resolution. The thermal saddle includes a base formed of a high heat dissipation material having spaced, planar flanges mounted within the camera housing. A concave, central portion is formed between the flanges and is sized to securely receive and support the deflection yoke and to dissipate heat therefrom. A strap surrounds the delection yoke and is secured to the base to securely mount the deflection yoke on the base.
    Type: Grant
    Filed: November 25, 1985
    Date of Patent: January 12, 1988
    Assignee: Applied Intellegent Systems, Inc.
    Inventor: Juan F. Velasquez
  • Patent number: 4694220
    Abstract: Electronic high-speed frame pick-up cameras for instantaneously or successively picking up an image of an object being observed while the structure and birghtness thereof are being changed at high speed. Each camera of this type consists of a first electron lens to reforming the photoelectronic image formed on the photoelectric layer, deflection means arranged so that the re-formed image of the photoelectronic image is located at the deflection center thereof, a singularity or plurality of second electron lenses arranged so that the electron beam deflected by the deflection means can be received thereby, a singularity or plurality of phosphor layers arranged to receive the electron beam sent from the second electron lens(es), a lens drive circuit to supply power to the first and second electron lenses, and a deflection means drive circuit to supply power to the deflection means.
    Type: Grant
    Filed: April 16, 1985
    Date of Patent: September 15, 1987
    Assignee: Hamamatsu Photonics Kabushiki Kaisha
    Inventor: Katsuyuki Kinoshita
  • Patent number: 4692658
    Abstract: The present imaging system, like prior imaging systems, includes an electron tube and an external solenoid which is disposed around a portion of the tube. An electron gun within the tube has a plurality of support beads located substantially symmetrically around the gun. Each of the beads comprises a body of insulating material having a first major surface and an oppositely disposed second major surface. A recess is formed in the first major surface and extends into the body of the material. A plurality of connectors corresponding to the number of supports beads are also provided. Each of the connectors comprises a single piece of metal having a proximal end, a distal end and a central body interconnecting both ends. The proximal end of each connector includes an embossment which conforms to the curvature of the leads which extend through a stem assembly of the tube.
    Type: Grant
    Filed: April 28, 1986
    Date of Patent: September 8, 1987
    Assignee: RCA Corporation
    Inventors: Louis D. Miller, Donald B. Kaiser
  • Patent number: 4622489
    Abstract: An improved image pickup tube has an insulating envelope with precisely formed inside and outside surfaces. The inside surface of the envelope has a diameter the midpoint of which lies on a longitudinally extending first mechanical axis. An electron gun is aligned with the first mechanical axis. The precisely formed outside surface of the envelope is substantially coaxial with the inside surface. The outside surface has a diameter the midpoint of which lies on a second mechanical axis that is substantially coincident with the first mechanical axis and the optical axis.
    Type: Grant
    Filed: July 19, 1985
    Date of Patent: November 11, 1986
    Assignee: RCA Corporation
    Inventor: Louis D. Miller
  • Patent number: 4558251
    Abstract: An improved image pickup tube has an insulating envelope with precisely formed inside and outside surfaces. The inside surface of the envelope has a diameter the midpoint of which lies on a longitudinally extending first mechanical axis. An electron gun is aligned with the first mechanical axis. The precisely formed outside surface of the envelope is substantially coaxial with the inside surface. The outside surface has a diameter the midpoint of which lies on a second mechanical axis that is substantially coincident with the first mechanical axis and the optical axis.
    Type: Grant
    Filed: September 30, 1980
    Date of Patent: December 10, 1985
    Assignee: RCA Corporation
    Inventor: Louis D. Miller
  • Patent number: 4520291
    Abstract: In a pick-up unit, a tube base for a camera tube is integrated with a coil former having a system of coils. As a result, the length of the pickup unit is small so that it is possible to manufacture portable cameras of small dimensions. The radial position of the tube with respect to the coil former is fixed by centering means provided in the tube base and in a sealing cap engaging the coil former. The axial position of the tube relative to the coil former is fixed by urging the tube against an abutting face of the sealing cap by means of a spring. The coil former is surrounded by a .mu.-metal screening sleeve consisting of two portions. The two portions of the screening sleeve are coupled together by means of a clamping ring.
    Type: Grant
    Filed: September 26, 1983
    Date of Patent: May 28, 1985
    Assignee: U.S. Philips Corporation
    Inventors: Henricus J. Van Rooy, Martinus J. Tops
  • Patent number: 4488085
    Abstract: An image pick-up tube which has a high signal to noise ratio relative to the prior art provides for a disk-shaped printed circuit board formed with a central opening through which the image can pass to strike the active part of the tube and wherein the printed circuit board carries a first amplifier stage which is very closely spaced and connected to the image pick-up means so as to provide minimum lead lengths to reduce stray capacitance and give high signal to noise ratio.
    Type: Grant
    Filed: March 22, 1982
    Date of Patent: December 11, 1984
    Assignee: Sony Corporation
    Inventors: Takashi Nakamura, Yoshihiro Morioka, Hiroyuki Sugimoto
  • Patent number: 4463253
    Abstract: A time dispersed sensor tube has a photocathode for receiving light images and converting them to photoelectrons. An anode adjacent the photocathode has a slit-diaphragm for accelerating photoelectrons and passing them to slit-jaws by way of a shutter electrode and counterelectrode. A deflection system is provided behind the slit-jaws for directing the photoelectrons to a screen. A short magnetic electron lens between the deflection system and the screen focuses the photoelectrons.
    Type: Grant
    Filed: June 17, 1983
    Date of Patent: July 31, 1984
    Assignee: Akademie der Wissenschaftler der DDR
    Inventors: Hartmut Lucht, Carl-Wilhelm Monch
  • Patent number: 4330797
    Abstract: A view-finder is used for a television camera which has an image pick-up device for picking up an image of an object responsive to incident light from the object. The television camera comprises an optical system for diverging a part of a light advancing from the object to the image pick-up device. The view-finder comprises a monochrome television picture receiving device which is supplied with an output signal of the image pick-up device and displays a monochrome picture image, and an optical system for composing the picture image of the monochrome television picture receiving device and an optical color image formed by the light diverged by the diverging optical system to form an optical image to be observed.
    Type: Grant
    Filed: May 28, 1980
    Date of Patent: May 18, 1982
    Assignee: Victor Company of Japan, Ltd.
    Inventors: Sumio Yokokawa, Itsuo Takanashi, Tadayoshi Miyoshi, Shintaro Nakagaki, Koichiro Motoyama, Kenichi Miyazaki
  • Patent number: 4249106
    Abstract: A radiation sensitive screen comprising a crystalline silicon substrate which is located on a side of incidence of radiation, and an amorphous silicon film which contains hydrogen and which is located on the opposite side of the substrate to the side of the incidence of the radiation. The radiation sensitive screen of this invention can be manufactured by a simple method, and can achieve a high resolution. It is useful for the target of an image pickup tube, the electron bombardment target of an X-ray fluorescence multiplier tube, etc.
    Type: Grant
    Filed: November 7, 1979
    Date of Patent: February 3, 1981
    Assignee: Hitachi, Ltd.
    Inventors: Eiichi Maruyama, Saburo Ataka, Kiyohisa Inao, Yoshinori Imamura, Toshihisa Tsukada, Yukio Takasaki, Tadaaki Hirai
  • Patent number: 4196369
    Abstract: In order to avoid picture disturbances by electric charging phenomena on the tube wall in a camera tube in which no target material is present on the inner wall of the cylinder tube, the tube wall is provided with a surface potential stabilizing material between the window connection and the mesh electrode of the camera tube. This stabilization can be realized by way of a local cover layer having the desired electric conductivity or secondary emission properties, or by locally adapting properties of the glass of the tube wall thereto.
    Type: Grant
    Filed: April 8, 1977
    Date of Patent: April 1, 1980
    Assignee: U.S. Philips Corporation
    Inventors: Jacob H. Geus, Louis M. Swart
  • Patent number: 4039888
    Abstract: A face-plate of an image pick-up tube having a plurality of electrodes formed thereon and a plurality of conductors provided for external connection extending from said plurality of electrodes across the outer periphery of the face plate to the outer surface thereof. At least one of the plurality of conductors for said external connection comprises a thin film which is electrically insolated from the other conductors by a thin insulating film formed thereon. This thin insulating film also serves to seal, in an air tight manner, a vacuum envelope together with the conductor or conductors for external connection extending to the outer surface of the face-plate.
    Type: Grant
    Filed: January 31, 1973
    Date of Patent: August 2, 1977
    Assignee: Hitachi, Ltd.
    Inventors: Mikio Ashikawa, Iwao Takemoto
  • Patent number: 3993926
    Abstract: Disclosed is an apparatus and method for determining the presence and position of a moving object within a static field. Basically, the invention utilizes a photocathode in combination with a storage mesh whereby a distributive charge may be stored upon the mesh indicative of light levels within the field. Positive and negative write operations are exercised at different points in time and are superimposed upon the storage mesh. The mesh is then read by means of deflection coils in combination with an aperture plate so as to sequentially scan the storage mesh and emit output signals correlated with the charges upon the mesh after positive and negative write cycles have been exercised. The invention incorporates the fundamental structures of an optical image correlator tube and an image dissector tube.
    Type: Grant
    Filed: October 7, 1974
    Date of Patent: November 23, 1976
    Assignee: Goodyear Aerospace Corporation
    Inventors: Bernard C. Rauckhorst, Harry O. Pfeiffer
  • Patent number: 3990038
    Abstract: An electron source is disclosed for generating a flow of electrons of substantially narrow energy distribution. Such a source may be incorporated into a cathode ray tube (CRT) where the beam of narrow energy electrons is modulated, as by a grid or other target element of the CRT; the current control characteristics of the CRT are dependent upon the energy distribution of the electron beam, and as the width of this distribution in the beam or flow of electrons is decreased, the sensitivity of the CRT is increased. In accordance with the teachings of this invention, the electron beam source includes a mirror element for critically absorbing incident electrons whose energy is above a predetermined value. Electrons whose energy is below the critical predetermined value are reflected from the mirror element to form an electron flow of a substantially uniform energy level.
    Type: Grant
    Filed: May 7, 1973
    Date of Patent: November 2, 1976
    Assignee: Westinghouse Electric Corporation
    Inventors: Arthur S. Jensen, Clarence Williams