High performance LED Illuminator IL104

High performance LED Illuminator IL104
Power spectra of the ultraviolet, blue, green and red LED Illuminator, respectively
Application example: generation of a light sheet for use in PIV

Principle

The LED illuminator IL104 is designed to provide continuous (CW) and pulsed light for high-speed videography and image based measurement techniques such as PIV (Particle Image Velocimetry), BOS (Background Oriented Schlieren), PROPAC (Projected Pattern Correlation), IPCT (Image Pattern Correlation Technique), shadowgraphy and schlieren.

The device generates extremely bright, non-coherent light. Available colors are red (623 nm), green (528 nm), blue (462 nm) or UV (390 nm). A version with white light emission is in preparation. The pulsed intensity is up to 14,000 lm (528 nm). The programmable delay allows the flashes to be precisely synchronized with different cameras.

All of the parameters of the device can be adjusted using a control software via an USB interface. These include:

  • continuous light intensity
  • pulse trigger mode
  • active trigger pulse edge
  • single or dual pulse mode (PIV)
  • light pulse width
  • light pulse power
  • pulse delay
  • pulse rate limitation

The parameters set using the computer are saved in non-volatile memory in the illuminator. This allows the device to be independently operated without a computer. Pushbuttons on the rear of the housing allow the user to choose the operational mode, turn the continuous light on and off, and trigger individual flashes.

The operating temperatures of the LED and power electronics are monitored. Separate temperature-controlled fans are used for active cooling. A variety of measures are used to protect the LED from being destroyed due to incorrect settings. The program monitors the pulse intensity, pulse length and maximum pulse frequency and dynamically adjusts the maximum values selectable by the user. Both the status of the device and any errors are displayed on the back of the device and in the software program.

The illuminator can be equipped with various C-mount lenses. It generates a defined, highly homogenous round illumination field of defined diameter suitable for imaging applications such as videographic recording, BOS and IPCT. In addition, light guides, for example from Schott, Fostec, Dolan-Jenner or Qioptiq, can be connected to the device using an adapter.

Awarded with the DLR Innovation Prize 2011.

Application

For example, image 3 shows a possible configuration using a fiber line light to generate a light sheet for use in PIV. In this arrangement the LED illuminator enables high-speed PIV fluid flow measurements at kHz frame rates.

Documents

Institute / Organization

DLR Institute of Aerodynamics and Flow Technology

Contact

Dr.-Ing. Boleslaw Stasicki
DLR Institute of Aerodynamics and Flow Technology

Jochen Krampe
Technology Marketing

Dr. Frank Holtmann
Technology Marketing