Research in the Fields of Phosphors |
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According to the article in a 1944 issue of Radio News magazine, phosphors were discovered in the 17th century by an Italian physicist. However, they remained primarily a scientific curiosity until a practical use for them was found in cathode ray tubes. Phosphors efficiently convert energy of various forms (beta rays, ultraviolet rays, and others) into visible light. They are available in a wide variety of colors and exhibit a "memory" which allows them to be used for storing an image (or other information) for seconds, minutes, hours, or even days. Anyone old enough to remember the old analog storage oscilloscopes is familiar with phosphorescent memory. As with many other technologies, phosphor knowledge gained significant advances during World War II, and the public was promised virtually limitless new conveniences based on those technologies once the nasty war was out of the way. The promise was kept. See also "Phosphors and Their Uses" in the December 1959 issue of Electronics World. There is also an unrelated feature at the bottom entitled "Radioddities" (radio oddities) which offers a few tidbits of trivia. It appeared on the same page in the magazine, so I included it here for your benefit. Research in the Fields of Phosphors
The war has tremendously accelerated research in the field of phosphors, which are tiny crystals that convert invisible radiations to visible light. Thousands of phosphors synthesized prior to the war had unusual properties, but low efficiencies. Today many uses have been found for these phosphors although they were previously ignored in the search for greater brilliancies. When blackout conditions were imposed, the despised phosphors received careful reconsideration by research men because the dark-adapted eye is some 200,000 times as sensitive as it is in daylight vision. The electrical energy applied to phosphor crystals creates light by changing the atomic structure of the crystals. When a swift cathode ray or quantum of ultraviolet strikes a phosphor crystal, one of the "bombed" atoms in the crystal is stripped of its least tenacious electron. This electron wanders through the crystal until it is trapped in one of the few imperfections. Some time later, latent heat energy again liberates the electron so that it can once more wander about until it chances to near its own "home" or another vacant site. On close approach, the electron dives into the parent haven, which acknowledges its arrival by a momentary scintillation of light. This simple act multiplied by "skintillions" emits light useful for commercial and scientific purposes. When this war ends and our fighting men return, they will have an opportunity to help achieve a resplendent new electronic era. Phosphor crystals in fluorescent lamps will inexpensively illuminate workplaces and homes or gaily brighten the streets of our cities with vari-colored sign-tubing. Other phosphor crystals will display news and entertainment on the screens of our television sets which may be tuned by the light from phosphors in "Magic Eye" tuning indicators. Kindred phosphors in the screens of microscopes will aid in fathoming the mysteries of bacteria and molecules in order to insure a healthier and happier life for all. Other possible uses for phosphor include intense light sources for sound recording and theater projection; in direct illumination wherein the very walls, ceilings, and murals luminesce to illuminate as well as decorate the room; luminescent plastics in thousands of forms to make night-time safer and more colorful; and phosphors emitting specific radiations for controlled treatments of living tissues and organisms. Although phosphorescent materials were discovered as early as 1603 by De Vicenzio Casciarolo, a Bolognese alchemist, it has been pointed out that the development of phosphors languished for more than three centuries until electronic television research devised highly efficient luminescent materials capable of glowing in practically any conceivable color. Phosphors are synthesized as clear tiny crystals measuring about one ten thousandth of an inch in size. These crystals gleam like miniature diamonds when viewed under a microscope. Phosphors are unique in being able to do the following: Instantaneously transform invisible radiations, such as cathode rays (swiftly-moving electrons) or ultraviolet, into visible light. Store light, or "remember" information for controllable time intervals lasting from less than a hundred-thousandth of a second to considerably more than a day. Convert electric power into white or colored light more efficiently than any other known practical means. Radioddities (not related to the phosphor article) Of the various receiving tubes offered by one representative manufacturer, 46 are combinations, 38 are triodes, 36 are diodes, 25 are tetrodes, 19 are converters, and 4 are eye-type indicators. One popular transmitting tube manufacturer makes only triodes. After acceleration by 1 volt, a single electron acquires a speed of 368 miles per second. Have you experimenters ever heard of a jar? This is a little-known electrical unit. 1 jar is equal to 1.11 μfd. capacitance. Tubes are used in building tubes! The precision spot welder used in tube manufacture is electronic. Barbara Fones writes radio script. Although New York State boasts the largest U. S. population, Mississippi has the most radios per home - almost 2 1/2 times the figure of New York. South Carolina is second highest. You can insulate with insulate. Insulate is the name of a special dielectric material. On New Year's Day in 1933, a prominent manufacturer of cathode-ray tubes and television equipment greeted his friends with "electronic holiday cards," which when "played back" in cathode-ray oscilloscopes reproduced a written greeting on the screen.
Posted June 17, 2021 |
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Development of new and highly efficient luminescent
materials by scientists in RCA Laboratories holds great promise of opening new fields
and activity in the postwar era.