Patents by Inventor Dietrich Fromm

Dietrich Fromm 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: 6218025
    Abstract: A sintered electrode of high-melting metal (for example tungsten) is produced from spherical metal powder having a well defined particle size. The mean particle size is from 5 to 70 &mgr;m. The particle size distribution covers a range from at most 20% below to at most 20% above the mean particle size.
    Type: Grant
    Filed: August 18, 1998
    Date of Patent: April 17, 2001
    Assignee: Patent- Truchand-Gesellschaft fuer Elektrische Gluelampen mbH
    Inventors: Dietrich Fromm, Bernhard Altmann, Wolfram Graser, Peter Schade
  • Patent number: 6069456
    Abstract: Lighting system, comprising a mercury-free metal halide lamp with a light yield of at least 75 lm/W and a color rendition index of at least 75 and an electronic ballast, the electronic ballast impressing a square-wave power supply on the lamp and keeping the power constant. The filling comprises the following components:a buffer gas which also acts as starting gas to start the lamp,a voltage gradient generator, comprising at least one metal halide which vaporizes readily and which is chiefly (by more than 50%) responsible for generating a voltage gradient which corresponds approximately to that of mercury, anda light generator comprising one metal and/or one metal halide.
    Type: Grant
    Filed: July 17, 1998
    Date of Patent: May 30, 2000
    Assignee: Osram Sylvania Inc.
    Inventors: Dietrich Fromm, Dieter Lang, Klaus Stockwald
  • Patent number: 5821696
    Abstract: Start and operation of high pressure discharge lamps, in which a high-frequency starting voltage U.sub.HF and an operating voltage U.sub.B are furnished to the lamp electrodes includes the steps of: 1) turning on the high-frequency starting voltage U.sub.HF at a starting time t.sub.0 to ionize the lamp filling and preheat the electrodes; 2) turning on the operating voltage U.sub.B after a preheating interval .DELTA.t.sub.H, that is, at time t.sub.1 =t.sub.0 +.DELTA.t.sub.H ; and 3) turning off the starting voltage U.sub.HF at time t.sub.2 .gtoreq.t.sub.1, as a result of which the lamp is then operated solely by means of the operating voltage U.sub.B. As a result, the transfer phase for the development of the arc is shortened. Advantageously, the frequency of the starting voltage is selected such that the product of the frequency f of the starting voltage U.sub.HF and the spacing d between the electrodes meets the condition f.multidot.d.gtoreq.50
    Type: Grant
    Filed: November 30, 1995
    Date of Patent: October 13, 1998
    Assignee: Patent-Treuhand Gesellschaft F. Elektrische Gluehlampen mbH
    Inventors: Dietrich Fromm, Joachim Arlt
  • Patent number: 5729091
    Abstract: A metal halide discharge lamp with a coaxial discharge vessel (2) and outer ulb (9) contains a fill of metals with a tendency to diffusion. Their specific content is less than 6 .mu.mols/cm.sup.3. The current supply leads (4, 5) are surrounded, over a large portion of their length, by a sheath (14) that is UV-shielded.
    Type: Grant
    Filed: June 20, 1996
    Date of Patent: March 17, 1998
    Assignee: Patent-Treuhand-Gesellschaft F. Electrische Gluehlampen mbH
    Inventors: Clemens Barthelmes, Andreas Hohlfeld, Jurgen Vom Scheidt, Dietrich Fromm
  • Patent number: 5461281
    Abstract: To prevent attack on electrodes (4, 5) within a discharge vessel (2) by an ionizable metal halide fill, due to spurious or free oxygen arising within the lamp during operation thereof, which oxygen combines with the metal of the electrodes, and is then dissociated in the arc and re-deposited at the hottest part of the electrode, an oxygen removing getter material is introduced into the discharge vessel. Spurious oxygen arises due to emission of oxygen from the glass wall of the discharge vessel, typically quartz glass, and unavoidable contaminants of the fill substance. The getter material is, preferably, phosphorus, boron or aluminum, a halide of the foregoing, a tungsten boron compound, a tin phosphorus compound, or scandium or a rare earth. If the getter is a halide, iodine, bromine or chloride are suitable. The getter may be introduced in quantities of between 0.05 to 0.6%, depending on the getter substances and the fill composition.
    Type: Grant
    Filed: July 7, 1994
    Date of Patent: October 24, 1995
    Assignee: Patent-Treuhand-Gesellschaft f. elektrische Gluehlampen mbH
    Inventors: Dietrich Fromm, Guenter Soehring, Richard Ullmann
  • Patent number: 5436533
    Abstract: To prevent bowing of the arc of a high-pressure discharge lamp operated horizontally, the lamp is supplied with alternating current of between 10 kHz and 100 kHz, in which the frequency and wave shape of the alternating current portions of the supply are so selected that standing radial acoustic resonances will be formed within the discharge medium or fill in the discharge vessel, which standing radially directed acoustic resonances suppress or counteract bending of the discharge arc due to convection phenomena.
    Type: Grant
    Filed: May 20, 1994
    Date of Patent: July 25, 1995
    Assignee: Patent-Treuhand-Gesellschaft F. Elektrische Gluehlampen mbH
    Inventors: Dietrich Fromm, Juergen Seehawer, Franz Bernitz
  • Patent number: 5363007
    Abstract: To provide a fill in a low-power, high-pressure discharge lamp, which is capable of emitting light within a warm white light (WDL) color or neutral white light (NDL) color, that is, in the ranges of between about 2600 to 4600K, the fill has a relative relationship of sodium halide to scandium halide between 5:1 and 24:1, a relationship of sodium halide to thallium halide of 25:1 to 73:1, and a heat damming or heat retention or reflection coating (15, 16) is located at the end caps of the generally bulbous discharge vessel to provide for a cold spot temperature (Tc) of at least C., and preferably higher.
    Type: Grant
    Filed: July 28, 1992
    Date of Patent: November 8, 1994
    Assignee: Patent-Treuhand-Gesellschaft fuer Elektrische Gluehlampen mbH
    Inventors: Dietrich Fromm, Andreas Hohlfeld, Guenter Soehring
  • Patent number: 5210463
    Abstract: Low-power, high-pressure discharge lamps, that is lamps having a power rag below and up to about 400 W, have a quartz discharge vessel retaining a metal halide fill which, to obtain a color temperature between to C. contains sodium and tin. To prevent deterioration of the electrode head (19; 39; 59), it is formed in essentially cylindrical or frusto-conical outer contour, which has a mass determined by the formula M=i.sub.L .times.(23.+-.8), and is retained on an electrode pin or shaft (17; 38; 58) having a diameter (d) in millimeters ##EQU1## wherein i.sub.L is the effective value of the lamp current in amperes. Preferably, the electrode head (19) extends beyond the end portion of the electrode pin to define a small depression with respect thereto. The particular shape and dimension of the electrode head and the electrode shaft reduces flicker and electrode burning.
    Type: Grant
    Filed: March 4, 1991
    Date of Patent: May 11, 1993
    Assignee: Patent Treuhand Gesellschaft fur Elektrische Gluhlampen m.b.H.
    Inventors: Dietrich Fromm, Andreas Hohlfeld
  • Patent number: 4633136
    Abstract: A high-pressure discharge lamp with metal halide additives and a power in of less than 100W comprises electrodes (4, 5) which have a shank portion (18) adjacent the seal and a second portion (19) which is formed as a coil and faces the discharge. Adjacent turns of the coil portion (19) do not contact one another. Shank (18) and coil (19) are preferably made of a single piece of wire. In the case of a double-ended arc tube (FIGS. 1 and 2) the axis of the coil portion (19) forms a substantially straight line with the shank portion (18). In the case of a single-ended arc tube (FIGS. 3 and 4) the axis of the coil portion includes an angle of with the axis of the shank portion. In order to protect the electrode, and especially the shank portion from corrosion, the shank (18) of the electrode (4, 5) is surrounded by a conical filament (17) of refractory metal e.g. tungston whose turns are lying closely together.
    Type: Grant
    Filed: April 13, 1983
    Date of Patent: December 30, 1986
    Assignee: Patent-Treuhand-Gesellschaft fur elektrische Gluhlampen mbH
    Inventors: Dietrich Fromm, Helmut Klingshirn, Achim Gosslar, Jurgen Heider
  • Patent number: 4291254
    Abstract: Discharge lamp energization circuit to operate a discharge lamp 1 over two electronic switches 10, 11, for example high-voltage, high-current switching transistors, which alternately apply a d-c voltage connected across two capacitors 4, 5, in opposite polarity, to the lamp circuit. The capacitors have the same value, and the lamp circuit includes a serially connected inductance. The electronic switching transistors are supplied from a frequency constant square-wave generator 16, at frequency high with respect to power line frequency, for example within the audio or supersonic range, e.g. 7.5 kHz. A separate ignition or starting circuit may be provided or the series inductance 2 and a capacitor 20 connected in parallel with the lamp may form a series resonance circuit tuned to a low odd harmonic (3, 5 7) of the lamp operating frequency.
    Type: Grant
    Filed: March 5, 1980
    Date of Patent: September 22, 1981
    Assignee: Patent-und-Gesellschaft fur elektrische Gluhlampen m.b.H.
    Inventors: Joachim Arlt, Dietrich Fromm
  • Patent number: 4171498
    Abstract: A high pressure electric arc tube discharge lamp utilizing low power input. he electrode spacing is less than 20 mm and the arc is electrode-stabilized. The arc tube is of isothermal design. The gas fill of the lamp contains a mixture of metal (i) iodides or (ii) iodides and bromides. The metal halides must include at least the halides of sodium and tin. Mercury is preferred as the buffer gas. When operating, the lamp has a low-color temperature, a luminous efficacy of 80 lms/W and a color-rendering index of about 75. It is suitable for use in interior lighting.
    Type: Grant
    Filed: November 25, 1977
    Date of Patent: October 16, 1979
    Assignee: Patent-Treuhand-Gesellschaft fur elektrische Gluhlampen mbH
    Inventors: Dietrich Fromm, Jurgen Seehawer, Wolf-Jurgen Wagner, Erich Winzerling