An effective method to introduce light shielding into transparent plastics.

Light shielding in backlit components avoids light bleeding into neighboring operating elements.

  • Laser Deep Printing requires no laser-absorbing additives for modification at depths of up to several mm.
  • Laser Deep Printing requires no changes in the process flows as it takes place at the very end of the manufacturing process.
  • Laser Deep Printing can efficiently introduce homogeneous light shieldings into transparent plastic components at reasonable speed and costs.
  • Light shieldings effectively reduce the transmission to below 35%. Several light shieldings in a row further reduce transmission.
  • Plastics: PC, PMMA, PET, ...

Light shielding in backlit components are usually created by elaborate 2-color back injection molding. Laser Deep Printing opens up significant cost savings in terms of

  • Investment in machine (1K instead of 2K)
  • Energy
  • Tool costs


Insights into Smart Coloring´s

Laser Deep Printing


Location-controlled focussing of ultra-short pulsed lasers creates visible dots, lines, areal and even complex geometric structures/shapes in transparent plastics.

Modified structures are built from the bottom up. Single pulse processing leads to separated structural elements.

The effect of spherical abberation leads (without a corresponding corecture) to an expansion of the introduced structure in the z-direction. The expansion in x,y direction remains unchanged.

Minimum structure sizes in x,y, and z-direction are about 2µm.

Laser Deep Printing - Variables

  • Puls duration     [ps]
  • Puls energy       [nJ]
  • Feed motion      [mm/s]
  • Puls distance    [µm]
  • Repetition rate  [kHz]
  • Depth z             [mm]




Cage-like or tubular structures act as a light shielding to prevent over-illumination into neighbouring areas.



The light barriers were introduced into various transparent plastics

  • In all plastics, these structures were achieved without the addition of laser-absorbing additives.
  • The highest darkening was achieved in PC.
  • In PET a medium dark coloration was achieved.
  • In PMMA, light/white structures were achieved