Technical Note:
The Oriel Flanging System

LS-205a
Figure 1: Our unique flanging system lets you couple numerous optical components directly to the output of our lamp housings, and ensure a closed optical path.

Three Series of Flanges

All our light source condensers have a female flange. We offer three sizes, we call them series, of condenser (the series size of each condenser is listed on the respective light sources pages). The “size” does not reflect the clear aperture, or beam size of the source. See below:

Condenser Series Size Actual Clear Aperture inch (mm)
1.5 Inch Series 1.3 (33)
2 Inch Series 1.9 (48)
3 Inch Series 2.7 (69)

Except for a few Research Sources and a limited selection of light source accessories for those condensers, all our instruments and components use the 1.5 Inch Series flanges. You can only couple components of the same series together, unless you use a Step Down Adapter. Step Downs convert a 2 or 3 Inch Series flange to a 1.5 Inch Series.

Set Screw or Quick Connect Flanges?

All of our 2 and 3, and most of our 1.5 Inch Series flanges use the set screw/groove method of coupling. For some of the smaller accessories, we offer both set screw and Quick Connect flanges.

Set Screw Method

  • More economical
  • Largest clear aperture
  • Suitable for permanent or semi-permanent set-ups

The set screw flanges use set screws to hold the male component firmly in place. If you are not going to break down the system frequently, this flanging system is suitable.

Quick Connect Method

  • Light tight
  • Fast and easy snap on and off

Female Quick Connects do not require set screws or any other hardware. They were designed to snap on and lock - ideal for set-ups that you'll change frequently. And, they're light tight too! The 77790 Quick Connect Adapter converts a 1.5 Inch Series set screw female flange to a Quick Connect Type. We use it to convert our 1.5 Inch Series light sources to quick connects so we can couple and remove filter holders, lens assemblies, fiber optics, etc. without fiddling with set screws. Note: the clear aperture is reduced from 1.3 inches (33 mm) to 1.2 inches (30 mm).


You can customize your general purpose light source by adding optical accessories. You can filter the beam, attenuate it, turn it, or add a fiber optic to carry the output to a remote location. Most of these accessories have flanges to couple to the source and/or to other accessories, to ensure a closed optical path. Fig. 1 shows two examples of customized light sources. Some optical accessories also have a tapped 1/4-20 hole to accept optical rods. If you're mounting several accessories to the condenser output, we recommend you also rod mount at least one for stability.