A tanning lamp with high persistent tanning and low erythemal output
Publication Date: 2005-Apr-12
The IP.com Prior Art Database
A tanning lamp with relative high persistent tanning and low erythemal output
The radiation spectrum of a tanning lamp consists of a UV-A part that causes direct pigmentation of the skin, and a part containing UV-B that causes persistent pigmentation. State of the art is the use of BaSi2O5:Pb (BSP) or SrB4O7:Eu (SBE) as a UV-A phosphor, in combination with a UV-B phosphor, for example LaPO4:Ce (LAP) or SrCe0.8MgAl11O18 (SAC).
The UVB phosphors LAP and/or SAC give persistent pigmentation. However, their radiation spectrum results also in erythemal radiation. A tanning lamp should tan with a minimum of erythemal radiation.
It it proposed to use a phosphor with a peak emission, of a few nm width, in the region between 300 and 315 nm. Between 300 and 315 nm, the persistent pigmentation is more effective than the erythemal action. Radiation in this region will result in relative low erythemal reaction and relative high persistent pigmentation.
Candidate phosphors are (Gd,La)B3O6:Bi (GLBB), CYB:Gd, GdPO4:Ce. One of these peak phosphors will be used in combination with a UV-A phosphor like BSP or SBE. Typical, the concentration of the peak phosphor will up to 20%.