Patents by Inventor Donald P. Northrop

Donald P. Northrop 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: 7300327
    Abstract: A method for constructing a scotopic after-glow lamp for use in an electric lamp with the scotopic lamp having a lamp wall is provided. The method comprises combining scotopic enhanced phosphors with after-glow phosphors, and layering the combined phosphors on the lamp wall with at least a portion of the after-glow phosphors being against the lamp wall and at least a portion of the scotopic phosphors being exposed to the electric arc of the lamp.
    Type: Grant
    Filed: June 15, 2005
    Date of Patent: November 27, 2007
    Inventors: Charles Bolta, Donald P. Northrop
  • Patent number: 6917154
    Abstract: A scotopic after-glow lamp for maximizing an eye's ability to see under low light conditions is provided. The scotopic after-glow lamp comprises a non-uniform scotopic phosphor blend of scotopic enhanced phosphors and after-glow phosphors. A method for constructing a scotopic after-glow lamp for use in an electric lamp is also provided. The method comprises combining scotopic enhanced phosphors with after-glow phosphors and layering the combined phosphors on the lamp wall with at least a portion of the after-glow phosphors being against the lamp wall and at least a portion of the scotopic phosphors being exposed to the electric arc of the lamp. Protective layers, such as aluminum oxide powder, can be added in conjunction with the coating process to reduce the flaking and/or separation of the phosphors from the glass wall of the lamp and each other and enhance and lengthen the useful light production of the lamp as it ages.
    Type: Grant
    Filed: February 25, 2003
    Date of Patent: July 12, 2005
    Inventors: Charles Bolta, Donald P. Northrop
  • Publication number: 20030160560
    Abstract: A scotopic after-glow lamp for maximizing an eye's ability to see under low light conditions is provided. The scotopic after-glow lamp comprises a non-uniform scotopic phosphor blend of scotopic enhanced phosphors and after-glow phosphors. A method for constructing a scotopic after-glow lamp for use in an electric lamp is also provided. The method comprises combining scotopic enhanced phosphors with after-glow phosphors and layering the combined phosphors on the lamp wall with at least a portion of the after-glow phosphors being against the lamp wall and at least a portion of the scotopic phosphors being exposed to the electric arc of the lamp. Protective layers, such as aluminum oxide powder, can be added in conjunction with the coating process to reduce the flaking and/or separation of the phosphors from the glass wall of the lamp and each other and enhance and lengthen the useful light production of the lamp as it ages.
    Type: Application
    Filed: February 25, 2003
    Publication date: August 28, 2003
    Inventors: Charles Bolta, Donald P. Northrop
  • Patent number: 5498924
    Abstract: A fluorescent lamp that has a T10 outer diameter which is capable of operating on ballasts of both the T8 and T12 types. In addition to the T10 diameter, the lamp has at least one groove in its wall to reduce the envelope cross-section, a fill gas of neon and argon, preferably 25% neon and 75% argon and a controlled amount of mercury.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: March 12, 1996
    Assignee: Duro-Test Corp.
    Inventor: Donald P. Northrop
  • Patent number: 4924368
    Abstract: A shatter-containment fluorescent lamp having a protective plastic sleeve in which the sleeve is attached by an adhesive at each end of the lamp envelope in a manner to provide a controlled air space between the glass lamp envelope and the plastic sleeve to prevent direct transmission of stresses from the envelope to the sleeve. The sleeve is also attached to the lamp base by the adhesive so that there is integral connection of the sleeve and the base at each end of the envelope. A retaining ring, also held by the adhesive, covers the base. In a preferred embodiment of the invention, the retaining ring inner surface and the lamp base having mating members to align the retaining ring on the base. In another embodiment, the sleeve has a number of angled slots around its circumference at each end and there are corresponding locking teeth on a retaining ring to accommodate for variations in lamp envelope/protective sleeve length.
    Type: Grant
    Filed: January 6, 1989
    Date of Patent: May 8, 1990
    Assignee: Duro-Test Corporation
    Inventors: Donald P. Northrop, David P. Strauss
  • Patent number: 4745323
    Abstract: A compact fluorescent lamp of the twin tube or double twin type which is protected by an outer envelope mounted to the fluorescent lamp or the housing which contains the fluorescent lamp ballast. In a preferred embodiment the outer envelope is in the shape of an incandescent lamp envelope.
    Type: Grant
    Filed: February 26, 1986
    Date of Patent: May 17, 1988
    Assignee: Duro-Test Corporation
    Inventors: Donald P. Northrop, Arpad L. Pirovic
  • Patent number: 4734616
    Abstract: A dual cathode structure for a fluorescent lamp comprises a pair of electron emissive cathodes which are connected with a common junction and mounted to have an included angle therebetween. The first of the pair of cathodes has first and second leads coupled to an external source of electrical current and the second cathode structure has a first terminal coupled to the first cathode at a common junction and an anode flag connected to its second terminal to collect electrons when the filaments are operating in the anode half cycle. The collected electrons pass through the second cathode. The availability of the second cathode prolongs lamp life by permitting shifting of the hot spot.
    Type: Grant
    Filed: October 1, 1986
    Date of Patent: March 29, 1988
    Assignee: Duro-Test Corporation
    Inventor: Donald P. Northrop
  • Patent number: 4032814
    Abstract: An energy saving fluorescent lamp utilizing a krypton-neon fill gas mixture and shielded electrode structures to operate at a reduced power consumption while serving as a direct replacement for another lamp, consuming a larger amount of energy, with the same ballast transformer.
    Type: Grant
    Filed: October 3, 1975
    Date of Patent: June 28, 1977
    Assignee: Duro-Test Corporation
    Inventors: Joel Shurgan, Donald P. Northrop
  • Patent number: 4032813
    Abstract: An energy saving fluorescent lamp utilizing a krypton-neon fill gas mixture and shielded electrode structures having a getter material thereon to operate at a reduced power consumption while serving as a direct replacement for another lamp, consuming a larger amount of energy, with the same ballast transformer. The getter material improves the starting characteristics of the lamps.
    Type: Grant
    Filed: June 24, 1975
    Date of Patent: June 28, 1977
    Assignee: Duro-Test Corporation
    Inventors: Joel Shurgan, Donald P. Northrop
  • Patent number: 3988633
    Abstract: A low pressure discharge lamp, particularly a fluorescent lamp, having a plurality of separate and continuous grooves along its length each of which is formed for 360.degree. around the envelope. The groove configuration maintains a generally arcuate cross-section of varying radius to thereby alter the wall recombination rate of the plasma ions with the phosphor. In the embodiments where the cross-section of the envelope as deformed by the groove is non-circular, the invention also acts to increase the plasma arc stream length thereby changing the electrical and luminous properties of the lamp. A method and apparatus for making the grooves using a plurality of heat sources is also described.
    Type: Grant
    Filed: January 30, 1975
    Date of Patent: October 26, 1976
    Assignee: Duro-Test Corporation
    Inventors: Joel Shurgan, Donald P. Northrop, Gordon D. Coplein