The WRTL/Indal Stela LED lantern from 2008, was revolutionary in the way its optics were designed utilising individual plastic lenses over each LED to amplify the light output and form the beam pattern.
The lens technology is now evolving even further as noticed in the Advanced LEDs Clara lantern - pictures courtesy of Clare.
In this view, the bottom array of LEDs are nearest the column and have diffuser style lenses.
The top array is nearest the road and has lenses designed to spread the light. They almost look like the "wings" of an ESLA.
With the lantern operating, the different beams are clear to see.
Interestingly, the Holophane V-Max uses exactly the same principle. These images are from examples in Nottingham. This version is a side road variant mounted on a sleeved concrete column. The coloured square is used to denote wattage.
A zoomed view of the image shows that the both of the 4 LED modules nearest the centre of the lantern use diffuse lenses, where as the outer modules have beam forming lenses.
The same principle applies to the main road version.
Finally, a Thorn R2L2 lantern in Newbury, unfortunately as the image was taken from a distance, the design of the optics aren't clear, although the wiring to the LED modules are!
