Xenon versus LED - What is the better light source?

With the ever increasing use of LEDs as light sources in all of our living and working areas, LEDs have also become the dominant source of lighting in stroboscopes. It that justified? 

Unfortunately, we also have to provide a non-trivial answer to this question. 

Let us start by clarifying the function of the light source in a stroboscope:

  • The light source should be bright
  • The brightness should be adjustable depending on the measurement task
  • In order for the measurement task to be carried out perfectly, the individual flash of light must be as short as possible. If the flash duration is too long, the measurement object moves too much which results in a blurred image.

Let us now add some further aspects to this:

  • Reasonable costs
  • Long service life / easy replacement
  • Pleasant light

We do not go into the “why” in the following assessment, as this would go beyond the scope of this analysis. 

Let us first consider the classic light source that has been used in recent decades: the xenon gas discharge lamp. Very good xenon lamps, as in our stationary and portable devices, exceed all requirements in terms of the achievable brightness and extremely short flash duration.

The disadvantage is that the xenon tube is subject to wear due to its use. The system-inherent combustion process slowly reduces the light intensity and ultimately the bulb has to be changed because no "Ignition" takes place any longer. The replacement must be carried out carefully and with caution, since very high voltages are required for the ignition when the devices are in operation. RHEINTACHO stroboscopes are designed so that the lamp can only be changed when it is in a safe status.

The change required at regular intervals naturally results in costs and unpredictable downtimes.

With LEDs there is a different situation.To achieve the required brightness, manufacturers take different paths:

  1.  A high number of LEDs are used
  2.  Extremely powerful LEDs are used. These are naturally more expensive than less powerful ones.
  3.  To achieve a brightness similar to that of xenon, the LEDs are controlled a little longer. I.e. the flash duration is a little longer. 

In the first two cases, an LED device can be expensive. In the latter case, the results are unsatisfactory in practical use. In general, it can be said that due to the technical progress of LEDs, the performance data has improved significantly and the costs have decreased in comparison. The brightness of LED stroboscopes can easily be optimally adapted to the application-specific lighting requirements. 

A big advantage is the extremely long, almost unlimited durability of the LEDs. The use of LEDs also leads to a long-term decrease in brightness. However, this is almost not recognized by the human eye.

Xenon stroboscopes still offer superior light quality today. However, the performance of LED devices has greatly increased. This means that for an estimated 90% of users and applications, LED stroboscopes are to be preferred over xenon devices due to the other advantages. All of this, of course, based on the high-quality RHEINTACHO devices.