Updated 24-XII-2018

Mary V. Hoffman

This article was written by fellow lamp engineer and collector Edward J. Covington, and originally appeared on his own website of biographical sketches of persons involved in the lamp industry. Following his passing in February 2017, and with kind permission of his family, Ed's words have been preserved here in the hope of maintaining access to his writings for the benefit of subsequent generations.

Mary V. Hoffman

Mary Virginia Hoffman was born in Kearny, New Jersey on January 1st 1927. Her education was received at Shaw High School in East Cleveland, Ohio and at Mather College of Western Reserve University (now Case-Western Reserve University) in Cleveland. Her major field was chemistry and a bachelor of Science degree was earned in 1949. In addition, graduate level courses were taken in chemistry at John Carroll University, Cleveland.

Mary Hoffman started her GE career as a Quality Engineer in October, 1949 at the Chemical Products Plant. She worked there on manufacturing methods as well as the testing of phosphors. She was also involved in the development of phosphors other than the halophosphate, the type commonly used in the four-foot 40-watt fluorescent lamp.

In 1964 a Phosphor Research Laboratory was established at Nela Park and Mary transferred into it. There she continued to develop new materials and did some trouble-shooting of processes. During that time she also looked for new materials by studying phase diagrams.

Working in cooperation with Ralph Hewes, line emission from Eu2+ was observed for the first time. Other work on yttrium vanadate became the basis for a color corrected mercury discharge lamp.

In 1964 Mary Hoffman transferred to Fluorescent Engineering as a Technical Manager. There she developed processes for the application of materials into the lamp and phosphor suspensions. She also developed double-coating methods. Phosphor blends were also worked on for improvements in color rendition.

Mary Hoffman earned a total of 17 U.S. patents while employed at GE Lighting. Her general area of concentration was on phosphors for discharge lamps. Ten of her patents involve new phosphors and/or processing, one involves a fluorescent lamp used for skin tanning, one deals with a fluorescent phosphate glass, four involve multilayer phosphor coatings in fluorescent lamps and one deals with a mercury vapor lamp that uses a phosphor material. 15 of the 17 patents are listed below.

  1. 2,824,814 - Fluorescent Coating Process - 1958/02/25 - with Shannon Jones
  2. 2,957,829 - Preparation of Luminescent Material - 1960/10/25
  3. 3,305,490 - Fluorescent Phosphate Glass - 1967/02/21
  4. 3,314,893 - Group ii Metal-Thorium Phosphate Phosphors - 1967/04/18
  5. 3,450,642 - Strontium Yttrate Luminescent Materials - 1969/06/17
  6. 3,450,643 - Alkaline Earth Yttrate Luminescent Materials - 1969/06/17
  7. 3,484,383 - Europium-Activated Strontium Magnesium Pyrophosphate Phosphors - 1969/12/16
  8. 3,630,945 - Divalent Europium Activated Alkaline Earth Aluminum Fluoride Luminescent Materials and Process - 1971/12/28
  9. 3,666,674 - Uranyl-Activated Strontium Zinc Pyrophosphate Phosphors - 1972/05/30
  10. 3,692,689 - Phosphor Comprising Lanthanum Cerium Thorium Phosphate - 1972/09/19
  11. 3,702,828 - Europium-Activated Barium and Strontium, Calcium Aluminum Fluoride Phosphors - 1972/11/14
  12. 4,645,969 - Skin Tanning Fluorescent Lamp Construction Utilizing a Phosphor Combination - 1987/02/24
  13. 4,751,426 - Fluorescent Lamp Using Multi-Layer Phosphor Coating - 1988/06/14 - with Gustino J. Lanese
  14. 4,806,824 - Fluorescent Lamp Using Multi-Layer Phosphor Coating - 1989/02/21 - with John Paynter, George R. Gillooly and Thomas F. Soules
  15. 4,847,533 - Low Pressure Mercury Dischrage Fluorescent Lamp Utilizing Multilayer Phosphor Combination for White Color Illumination - 1989/07/11

  1. "Women Scientists - Biographical Sketches and Their Contributions to the GE Lamp Business", Edward J. Covington, January 1992, 10 pages.
  2. European Patent Office Website (esp@cenet Advanced Search)