LED Luminaries

LED news and insight from our technology editor Steve Bush, who has been messing with LED lighting for more years than he would care to remember.

Cavers and miners will be happy

Ledil Crystal Mine and RSCavers and miners will be happy, as Ledil has made a collimator especially for them.

Called Crystal, beams down to +/-1.5° are possible.

There are two products: Crystal-RS and Crystal-Mine.

“According to mining head lamp specifications Crystal-Mine has 10% added illumination over the cut-off area,” said Ledil. “In comparison Crystal-RS is designed to have a tight uniform beam and a maximum candela peak.”

All credit to Ledil is due because the company has put led-to-collimator dimensions in the data sheet.

Without this, and almost no company reveals this critical distance without being asked specifically, it has to be discovered by accurately measuring a holder – which is prone to errors because of tolerance build-up.

In the case of Crystal/XP-G, this distance is 0.1mm from the rear face of the collimator to the top surface of the LED substrate – which would be slightly more useful, if the dimension was to the led mounting face – but it is so much better than no information at all.


  • Beam: real spot
  • Typical efficiency: 89%
  • Typical FWHM: 5.1° (+/-2.5°)
  • With Cree XP-G:   4.9°   89%   68.29cd/lm


  • Typical efficiency: 90%
  • Typical FWHM: 4.9°
  • With Cree XP-G:  4.7°   90%   66.9cd/lm


  • Height: 28.7 mm
  • Diameter: 49.7 mm
  • Optical grade PMMA
  • UL94 HB rated
  • -40 to +100°C


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