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Infrared to Visible Conversion Phosphor

IP.com Disclosure Number: IPCOM000077228D
Original Publication Date: 1972-Jun-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Halpin, AT: AUTHOR [+2]

Abstract

This phosphor system is particularly suitable for applications with an infrared (IR) source to convert the IR to visible light. For example, it can be applied as a coating to a light-emitting diode (LED) of GaAlAs or GaAsP which has a wavelength in the IR range, i.e. less than 9000 Angstroms. When the LED emits the IR, the phosphor coating converts the IR to visible light.

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Infrared to Visible Conversion Phosphor

This phosphor system is particularly suitable for applications with an infrared (IR) source to convert the IR to visible light. For example, it can be applied as a coating to a light-emitting diode (LED) of GaAlAs or GaAsP which has a wavelength in the IR range, i.e. less than 9000 Angstroms. When the LED emits the IR, the phosphor coating converts the IR to visible light.

The phosphor is basically composed of a rare earth i.e. Y, oxysulfide compound as host material, Nd as sensitizer and Er or Tm as one of the activators depending upon the desired wavelength. The phosphor system has a chemical formula of: O=Y-S-Y=O (Nd/3+/:Er).

The yettrium oxysulfide compound is doped with neodymium and erbium. A typical composition of the compound is listed as follows: Yttrium oxide Y(2)O(3) (69 grade) 180 grams Neodymium Nd(2)O(3) (59 grade) 8 grams Erbium oxide Er(2)O(3) (59 grade) 10 grams Sulfur (69 grade) 192 grams Sodium carbonate Na(2)CO(3) (69 grade) 80 grams.

The ingredients of the composition are mixed by a conventional ball mill dispersion method for 24 hours to obtain an even mixture and grain. Next, the mix is annealed for three hours at a temperature of 1000 degrees C in a nitrogen environment. Then the compound is washed by deionized water and dried in a heated vacuum oven.

Nd/3+/ absorbs and converts external energy with wavelengths of 8100 Angstroms, 7900 Angstroms, and 6500 AngstromsA. The Nd/3+/ transfers its converted...