RLOD#30 (2020.06.08) 1999 Philips DL35/745

The DL35/745 is a xenon-metal halide lamp aimed at non-automotive lighting applications where a high instantaneous light output is not required right after ignition. As a result, the xenon fill pressure in DL lamps is lower than in their automotive counterparts and the model shown here has the lowest pressure of all, 0.3 bar cold, which enables the use of a standard 5 kV ignitor. This particular model was released in 1999 for simple lighting systems (instrument illuminator, light engine for fiber optics system, etc.) which requires a compact source of high brightness but do not necessitate an instant hot restart of the lamp (although up to 23 kV can still be applied to its terminals). Except for its fill pressure, the DL35/745 has a design that is virtually identical to that of the standard automotive D2. The same sodium-scandium iodide fill chemistry and dosage are used but the lower operating pressure of the DL type (8.5 bar vs. 80 bar) changes the arc temperature distribution, resulting in a higher color temperature (4500 K) and an improved color quality (70 Ra8) of the emitted light. The light output is also higher (3.6 klm, initial) and results in a record high initial lumen efficacy (for this lamp type) of nearly 103 lm/W. It is 91.4 lm/W in standard 35 W automotive lamps.