Patents by Inventor Yew C. Chang

Yew C. Chang 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: 4755501
    Abstract: A color developing composition for pressure-sensitive recording systems comprising an admixture of an alkylidenediphenol and calcium carbonate having a weight ratio of about 2 parts to about 20 parts phenol per 100 parts calcium carbonate. The admixture is formulated in high solids content coating colors having excellent rheological property and stabilty, which are used to produce CF sheets having a coating weight of about 4 to about 10 g/m.sub.2. Preferably, the composition comprises Bisphenol A in an amount of 4 to 10 parts per 100 parts calcium carbonate and the calcium carbonate weight % in the CF coating is greater than 50%. Other embodiments comprise an aqueous dispersion of the admixture, a pressure-sensitive recording manifold and methods of making the dispersion.
    Type: Grant
    Filed: May 18, 1984
    Date of Patent: July 5, 1988
    Assignee: Amoco Corporation
    Inventors: Yew C. Chang, Richard S. Lamar
  • Patent number: 4732748
    Abstract: Finely divided, wet-ground, dispersant-free calcium carbonate filler or pigment compositions are disclosed in which the particles of calcium carbonate are distributed in particular amounts in a particular fashion--broadly stated: in fine particle size distribution. Such compositions are useful in aqueous slurry or dry form as opacifying fillers for paper.
    Type: Grant
    Filed: December 10, 1986
    Date of Patent: March 22, 1988
    Assignee: Cyprus Mines Corporation
    Inventors: Robert D. Stewart, Norman O. Clark, Yew C. Chang
  • Patent number: 4314013
    Abstract: An improved photoelectrophorectic imaging process which comprises placing a suspension of double encapsulated electrically photosensitive particles in an electric field between a pair of surfaces, exposing the suspension to a pattern of electrogmagnetic radiation and separating the surfaces whereby the exposed portion of the suspension adheres to one surface and the unexposed portion adheres to the other surface. The imaging particles are comprised of a first resin which encapsulates a colorant for the particle and second resin which encapsulates the first resin and contains the electrically photosensitive material.
    Type: Grant
    Filed: April 4, 1979
    Date of Patent: February 2, 1982
    Assignee: Xerox Corporation
    Inventor: Yew C. Chang
  • Patent number: 4106939
    Abstract: Selected areas of a layer comprising an imaging material in the form of a tellurium tetrahalide adduct of an aromatic amine, exemplified by a tellurium tetrachloride adduct of dimethyl aniline, which adduct is free from any diazo groups, in the presence of a spectral photosensitizer, are subjected to the imaging effect of imaging energy, and of development, advantageously of developing energy, causing a change in the tellurium-organic imaging material in the imaged areas accompanied by a change in the detectable characteristic of the imaging material in the imaged areas. The aforesaid imaging material is especially advantageously extended in a matrix of a polymeric or resinous film-forming material. The invention in its generally most advantageous form involves an imaging step employing imaging energy and producing a latent image, followed by a heat development step to produce the detectable recorded information or image.
    Type: Grant
    Filed: October 3, 1977
    Date of Patent: August 15, 1978
    Assignee: Energy Conversion Devices, Inc.
    Inventors: Yew C. Chang, Stanford R. Ovshinsky, David A. Strand
  • Patent number: 4066460
    Abstract: Selected areas of a layer comprising a tellurium tetrahalide imaging material, exemplified by tellurium tetrachloride, are subjected to the imaging effect of imaging energy, and of developing energy causing a chemical change in the tellurium tetrahalide imaging material in the imaged areas accompanied by a change in the detectable characteristic of the imaged areas. The aforesaid imaging material is extended in a matrix of a film-forming material together with a sensitizer. The application of the energy is advantageously effected in two steps, an imaging step employing imaging energy and producing a latent image, followed by a development step employing developing energy and producing the detectable recorded information or image.
    Type: Grant
    Filed: July 17, 1975
    Date of Patent: January 3, 1978
    Assignee: Energy Conversion Devices, Inc.
    Inventors: Yew C. Chang, Stanford R. Ovshinsky, Ronald W. Citkowski