Patents by Inventor Robert A. Hedler

Robert A. Hedler 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: 4405880
    Abstract: The invention provides an advantageous blend of green and orange-emitting phosphors to constitute an improved substantially yellow-emitting screen component in a data display CRT. The blended component evidences medium-long persistence and thereby provides substantially flicker-free imagery when the tube is expeditiously employed in conjunction with field refresh rates of 20 to 40 Hz.
    Type: Grant
    Filed: June 11, 1981
    Date of Patent: September 20, 1983
    Assignee: North American Philips Consumer Electronics Corp.
    Inventors: Anthony V. Gallaro, Robert A. Hedler
  • Patent number: 4377768
    Abstract: The invention provides an advantageous blend of green, orange and blue-emitting phosphors to constitute an improved white-emitting screen component in a data display CRT. The improved white-emitter evidences medium-long persistence and thereby provides flicker-free imagery when the tube is expeditiously employed in conjunction with field refresh rates of 20 to 40 Hz.
    Type: Grant
    Filed: June 11, 1981
    Date of Patent: March 22, 1983
    Assignee: North American Philips Consumer Electronics Corp.
    Inventors: Anthony V. Gallaro, Robert A. Hedler
  • Patent number: 4128674
    Abstract: A pigmented phosphor comprises a core of a phosphor particle having a light modifying layer thereon. The light modifying layer is comprised of a co-precipitated mixture of silica or pyrophosphate and a pigment which modifies the light output of the energized phosphor. The phosphor is coated by first preparing an unique pigment stock suspension containing the pigment, water, and a polyacrylamide dispersant. The stock solution is then diluted and phosphor particles are added thereto and the mixture is vigorously stirred. The pH of the mixture can be adjusted to about 5 by the addition of acetic acid and then a small amount of positively charged colloidal silica or pyrophosphate is added. After mixing, the pH is raised to about 9 by the addition of a base or a salt which causes a gel to form and the silica or pyrophosphate and the pigment to co-precipitate out upon the phosphor particles.
    Type: Grant
    Filed: March 31, 1976
    Date of Patent: December 5, 1978
    Assignee: GTE Sylvania Incorporated
    Inventor: Robert A. Hedler
  • Patent number: 4020231
    Abstract: A composite article comprises a core of a phosphor particle having a light modifying layer thereon. The light modifying layer is comprised of a co-precipitated mixture of a free-flowing agent such as silica or pyrophosphate and a pigment which modifies the light output of the energized phosphor. Also disclosed is a method of making the composite article which comprises the steps of preparing an aqueous mixture of particles of phosphor, particles of a pigment and a positively charged colloidal silica or pyrophosphate and mixing thoroughly. After mixing, a base, in the case of silica, or a salt which will form an insoluble pyrophosphate in the case of the pyrophosphate, is added thereto in sufficient amount to gel the mixture causing the silica or pyrophosphate and the pigment to co-precipitate upon and coat the phosphor particles. After the coating operation the supernatant liquid is removed and the coated phosphor is dried.
    Type: Grant
    Filed: March 31, 1976
    Date of Patent: April 26, 1977
    Assignee: GTE Sylvania Incorporated
    Inventors: Robert A. Hedler, W. Wentworth Slobbe