With pre objective scanning the scan head is located before the objective in the beam path. There are 2 types of objectives usual for pre objective scanning: 

• A f-Theta objective keeps the laser beam focus in a flat plane while scanning the entire scan field. Therefor these objectives are also called flat field lenses.
• A telecentric f-Theta objective keeps the laser beam focus in a flat plane while scanning the entire scan field and furthermore keeps the incident laser beam perpendicular to the scan field.
  Typically, for vision, measurement and micro material processing sloping beams respectively to the target are not accepted. For these applications we recommend telecentric f-Theta objectives, where the beam incidents right-angled over the entire scan field.

ARGES delivers a wide range of f-Theta objectives. Therefore, you can individually select  the most suitable optics for your applications. Most of the objectives are kept on stock.