Sylvania Ellipsoidal Reflector ER95
The first blown-bulb reflector lamps were introduced in 1936, following their invention by Royal Strickland of GE's Large Lamp Department. During the next four decades these so called R-lamps were the workhorses of accent and display lighting, and subequently earned popularity when recessed deeply into new low-glare track and downlight luminaires during the boom of these fixtures in the 1970s.

Around this time another GE engineer, Frank LaGiusa astutely recognised that a significant proportion of their light was being wasted and absorbed by the interior side walls of these recessed luminaires. He solved this problem with his invention of the so-called ER or Ellipsoidal Reflector lamp.

Although naked ER and R lamps achieve similar beam angles and photometric performance, the difference when installed in a recessed luminaire is so profound that a 75W ER95 / ER30 lamp can achieve the same output as a 150W R125 / R40. With the R-type parabolic reflectors, the divervence of the light rays begins immediately in front of the bulb and a large proportion of output is absorbed by the black interior of the luminaire. However with an ER lamp the light rays are focussed to a point two inches ahead of the bulb centre before diverging. This efficiently allows light out of a deep luminaire without impinging on its sidewalls and being lost.

The ER lamp achieved tremendous success in the USA, however in Europe the downlight is used to a much lesser extent. Nevertheless in 1980 a high voltage version was introduced by American manufacturer GTE Sylvania. Inevitably the demand for such a lamp in Europe was minimal and by 1987 the production was stopped.
Manufacturer: GTE Sylvania
Lamp Power: 75 Watts  
Lamp Voltage: 240 Volts  
Lamp Current: 0.31 Amperes  
Cap Type: E27/27 Brass + Vitrite
Bulb Type: ER-95 ER-30 in eighths/inch
Bulb Finish: Inside Frosed Aluminised
Filament Type: CC-9 Coiled-Coil Wreath
Atmosphere: 87% Argon 13% Nitrogen
Luminous Flux: N/A
Luminous Efficacy: N/A
Peak Intensity: 750 cd
Beam Distribution: 35° to 50% peak intensity
Colour Temperature & CRI: CCT: 2700K CRI: Ra 100
Chromaticity Co-ordinates: CCx: 0.460 CCy: 0.411
Rated Lifetime: 1000 hours to 50% survival
Burning Position: Universal
Overall Length: 135 mm 6½ inches
Light Centre Length: N/A
Factory: Lyon France
Date of Manufacture: circa 1985
Original / Present Value: Unknown Unknown
 
References: 1) US Patent 4,041,344 "Ellipsoidal Reflector Lamp", Frank LaGiusa, General Electric Co. U.S.A.