Patents by Inventor Cha-Mei Tang

Cha-Mei Tang 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).

  • Patent number: 6252938
    Abstract: A grid, for use with electromagnetic energy emitting devices, includes at least metal layer, which is formed by electroplating. The metal layer includes top and bottom surfaces, and a plurality of solid integrated walls. Each of the solid integrated walls extends from the top to bottom surface and having a plurality of side surfaces. The side surfaces of the solid integrated walls are arranged to define a plurality of openings extending entirely through the layer. All of the walls can extend at 90° with respect to the top and bottom surfaces, or alternatively, some of the walls can extend at an angle other than 90° with respect to the top and bottom surfaces, such that the directions in which the walls extend all converge at a point in space at a predetermined distance from the front surface of the at least one layer. At least some of the walls also can include projections extending into the respective openings formed by the walls.
    Type: Grant
    Filed: December 13, 1999
    Date of Patent: June 26, 2001
    Assignee: Creatv Microtech, Inc.
    Inventor: Cha-Mei Tang
  • Patent number: 5955849
    Abstract: A field emitter for producing an electron beam includes at least one cold cathode unit. Each of the cold cathode units includes an emitter cone having an emitter tip and a gate spaced apart from the emitter tip for extracting electrons from the emitter tip in a propagation direction upon application of a positive dc voltage on the gate with respect to the emitter tip. The gate forms a gate cavity for propagation of the extracted electrons therethrough. Each of the cold cathode units further includes at least one lens electrode disposed further in the propagation direction from the emitter tip than the gate, the at least one lens electrode forming at least one lens cavity for propagation of the extracted electrons therethrough. The at least one lens electrode is for focusing the extracted electrons in part of the gate cavity, part of the at least one lens cavity, and part of the region therebetween.
    Type: Grant
    Filed: February 25, 1994
    Date of Patent: September 21, 1999
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Cha-Mei Tang, Antonio C. Ting, Thomas A. Swyden
  • Patent number: 5949850
    Abstract: Methods for making large area grids consisting of focused and unfocused holes in sheets of metal. The grid consists of thin metal walls surrounding hollow openings. The projection of all walls converge to a focal spot in the focused grid, and on parallel or substantially parallel in an unfocused grid. A grid having a large area is made by interlocking together smaller grid pieces. A tall device is made by stacking layers of focused grids. Methods to make unfocused grids that detect parallel incoming x-rays are also described. The opening of the grid can be filled with phosphor or other scintillating materials to make a integrated grid/scintillator structure. These grids can also be applied to many applications such as x-ray antiscatter for diagnostic medical imaging, non-destructive testing, x-ray collimation, filters for liquids or electromagnetic radiation.
    Type: Grant
    Filed: June 19, 1997
    Date of Patent: September 7, 1999
    Assignee: Creatv MicroTech, Inc.
    Inventor: Cha-Mei Tang
  • Patent number: 5793152
    Abstract: The present invention is a device for producing collimated electron beams. The device comprises a gated field emission array having at least one emission tip and a grid electrode having a grid opening disposed above the emission tip in a first direction. The device also comprises an integrated planar lens electrode for producing a focusing effect on electron beams emitted by the emission tip. The planar lens electrode has a lens edge disposed aside at a distance from the grid opening in a second direction perpendicular to the first direction. Preferably, the planar lens electrode is an integrated layer with the gated field emission array on a substrate. The grid electrode and the lens electrode can be on the same layer and separated by a gap of vacuum. The planar lens electrode can be above the grid electrode, separated by an insulative material. Similarly, the planar lens electrode can be below the grid electrode, and separated by an insulator material.
    Type: Grant
    Filed: December 3, 1993
    Date of Patent: August 11, 1998
    Assignees: Frederick M. Mako, Ansel M. Schwartz
    Inventors: Cha-Mei Tang, Thomas A. Swyden
  • Patent number: 5729583
    Abstract: An x-ray head according to the invention includes an evacuated chamber in which a cathode and an anode are disposed and electrical connections from the anode and cathode extending through the wall of the evacuated chamber. The cathode may include a gated array of field emission elements, an array of solid state miniature thermionic cathodes, or ferroelectric cathodes. The anode is a metal producing x-ray radiation in response to the impact of electrons produced by the cathode. The anode may be a foil, a thin film of metal deposited on the inside surface of a wall of the evacuated chamber, or a self-supporting body of a metal that produces x-rays in response to electron impacts. The wiring may include conventional pins penetrating through and sealed to the wall of the chamber for connection to a flexible cable.
    Type: Grant
    Filed: September 29, 1995
    Date of Patent: March 17, 1998
    Assignee: The United States of America as represented by the Secretary of Commerce
    Inventors: Cha-Mei Tang, Richard D. Deslattes
  • Patent number: 5497053
    Abstract: An electron deflection device responsive to an electrical input signal for producing an output signal includes a focusing array for producing a collimated electron beam input ribbon in the direction of a propagation axis, the input ribbon being elongated along an array axis perpendicular to the propagation axis, and being relatively thin along a deflection axis perpendicular to the array axis and to the propagation axis. The focusing array is preferably a linear array of gated cold cathode units with lens electrodes. The deflection device further includes first and second electrically conductive deflector faces, forming a deflection region therebetween and being disposed so that the propagation-axis passes through the deflection region.
    Type: Grant
    Filed: November 15, 1993
    Date of Patent: March 5, 1996
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Cha-Mei Tang, Antonio C. Ting, Thomas A. Swyden