Advanced Processing

Aspheric Processing

LaCroix Precision Optics has a variety of different top of the line aspheric machinery that utilize unique kinematics to reduce mid-spatial frequencies and improve form error. Current machinery includes:

  • 200 SPM Loh Aspheric Grinder
  • 200 SPS Loh Aspheric Polisher
  • 150 ESX Optipro Aspheric Grinder
  • 125 Loh Aspheric Polisher
  • 2x300 UFF Optipro Aspheric Polisher
  • Optipro Profilometer
  • UltraSurf 3D Metrology
  • Q22-Y
  • Q22-XE
Processing cell

Aspheric processing begins with designing a near net shaped optical glass blank and then grinding a best fit sphere onto the aspheric surface. From this point, the initial aspheric profile is ground onto the aspheric lens using one of our aspheric grinders.

Metrology is then used to define the surface of the asphere and characterize all deviations from theoretical form, this information is then used to correct and reduce form error on the aspheric surface. A fine grind is performed to reduce sub-surface grinding damage and prepare the asphere for polishing.

Asphere UFF
SPM200

The aspheric lens is then greyed out, removing the subsurface damage surface. This begins a corrective feedback loop between metrology and the aspheric polishers.

When necessary a post polish is performed using MRF to reduce form and slope error.

Asphere
Form error 2.0 µ 1.0 µ 0.3 µ

MRF

MRF (Magnetorheolgical Fluid) utilizes magnetically-sensitive fluid to create a ribbon that is used to polish optics. The MRF is manipulated using a magnetic field to adjust the viscosity of the fluid and thus adjust the removal rates. The lens is then pulled across the ribbon in either a spiral or raster path.

MRF can produce significant increases in quality.  Spherically lamba/20 surfaces can be achieved and aspheric surfaces can reach lamba/4, as well as reduce mid-spatial frequency errors.

Types of Optics

  • Spherical
  • Aspheres
  • Prisms
  • Planos

Machines

  • Q22-Y
  • Q22-XE