Evaluation of Microencapsulated Phosphors.
Abstract
To determine how encapsulation affects the light output of electroluminescent phosphors, direct comparisons were made between plain and microencapsulated phosphors of the same control lot with nominal 0.5, 1.0, and 3.0-micron walls. Light output was normalized with respect to the amount of phosphor as a general procedure. Examination under magnification revealed that the encapsulating coatings formed diametric protrusions on the phosphors; however, theoretical studies subsequently indicated that the conical shaped ends probably would not act as light tubes to enhance the apparent light output. Factors such as coating thickness, phosphor composition and concentration, spectral emission, and origin of the emission were studied. Shifts of emission wavelength and emission peaks were noted with decreasing temperature down to about - 265C for both UV and electrical excitation. Encapsulation had no significant effect on the output of UV excited phosphors. The program was concluded with work to confirm the results of initial AFML work which had indicated that microencapsulation enhanced the light output of phosphors. The original results were not confirmed although the same procedures and material lots were used. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1979
- Accession Number
- ADA073448
Entities
People
- O. A. Ullrich
- P. E. Mccrady
- R. B. Reif
- T. S. Shilliday
Organizations
- Battelle Memorial Institute