1988 GE FBE (650 W / 120 V)

A color-filtering bulb was first combined with a high-wattage halogen lamp in the second half of 1986 when GE (USA) introduced the 650 W FAY/FBE, characterized by a high light color temperature. These particular lamps were designed as a source of artificial daylight for stage and studio applications, and are built around a compact double-ended halogen burner, enclosed in a shallow aluminized PAR36 mirror that projects a 25x15° beam (at half peak intensity). An interesting feature of the halogen source is its moly end seals, which are of the cold-rolled type, i.e., made by rolling the middle section of a molybdenum wire, a design typically found in some older quartz lamps made by GE. The difference between the FAY and the FBE lies only at the electrical contacts: the former is provided with ferrules and the latter has screw lugs. Both lamp types are designed to be supported in luminaires at the bulb rim, which is used as an optical reference plane.

A high light color temperature of 5000 K is achieved thanks to an optical filter applied on the front end of the lamp, which reflects in a broad spectral range in the red, orange and yellow. Because of the compact nature of the FBE, this filter is of the multilayer dichroic kind in order to withstand the high operating temperature. Moreover, the efficient production of the cool-white light is also achieved thanks to a filament driven at high temperature (3400 K), which enhances the production of light in the blue end of the spectrum. However, this also limits the lamp service life to 35 h only, which is long enough for the intended application.