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Prism Limits

PrismsBelow are manufacturing limits and tolerances specific to optical prisms. For more detailed information on any attribute,  please contact sales@optimaxsi.com.

General Comments on Manufacturing Limits

  • This represents a general list of soft limits and is intended for reference only.
  • As requirements move closer to a min or max shown, the more challenging the part will be.

Manufacturing Limits for Prism Surfaces

Attribute
Minimum
Maximum
Diameter (mm) 3 300
Thickness 1 150
Aspect Ratio1 1 502

General Comments on Tolerancing Limits

  • This represents a general list of soft limits and is intended for reference only.
  • Reducing tolerance range increases costs.
  • Robust sensitivity analyses will help yield the most cost effective tolerancing.

Tolerancing Limits for Prism Surfaces

Attribute
Prism Tolerancing Limit
Glass Quality (nd, vd) Melt Rebalanced and Controlled
Diameter (mm) +0, -0.010
Center Thickness (mm)3 ± 0.010 
Sag – Concave (mm)  ± 0.010 
Clear Aperture  100%4
Power5 0.1 HeNe fringes6
Irregularity – Interferometry (HeNe fringes)7 0.18
Wedge Prism (window) – ETD (mm)9 0.00210
Bevels – Face Width @ 45° (mm)11 sharp 
Scratch – Dig (MIL-PRF-13830B)12 10 – 5 
Surface Roughness (Å RMS)13 4

1Diameter divided by thickness
2This represents highest values obtained. When at maximum other minimums (irregularity) may not be possible. Will be smaller with less well behaved materials.
3This is for the most well behaved materials. More difficult materials (CaF2, Ohara S-FPL, etc.) will need larger tolerance ranges.
4Of full aperture (FA)
5In addition to irregularity
6This represents lowest values obtained. Will grow with diameter. Will be larger with less well-behaved materials.
7Typical metrology is Zygo MetroPro plot for interferometry.
8This represents lowest values obtained. Will grow with diameter. Will be larger with less well-behaved materials.
9Also known as parallelism or pyramidal error in prism manufacture.
10Tighter specification is possible but can be extremely expensive. For a more economical limit, please consider using 0.005mm.
11Subject to measurement uncertainty
12Crystals and reflective materials will receive 40W inspection
13This represents lowest values obtained. Actual values for crystalline materials, especially polycrystalline, will be higher.
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