Spheres, the most common type of optic, have at least one surface that is a segment of a ball. A spherical lens is made with a particular radius of curvature. This radius can be as short as 1mm or very long, to where plano is an infinite radius. Spheres are found in camera lenses, machine vision systems, laser beam shaping, and similar applications.
We’ll walk you through the process, and invite you to visit the Resource Library for technical resources at every step.
Specifying spheres begins with choosing an optical material. Next, the designer selects a diameter, thickness and surface radii. Finally, mechanical and optical attributes are toleranced in accordance with the designer’s performance requirements and the manufacturer’s capabilities
Reducing the range of a tolerance will add manufacturing cost. The task in selecting tolerances is to minimize cost while ensuring good optical performance. The Cost of Tolerancing gives valuable insight into optimally tolerancing optical components, written in collaboration between an optical engineer, an optics manufacturer, and a metrologist.
For more information on our sphere manufacturing please see:
Optimax makes spheres from optical materials such as glass, fused silica, crystals and ceramics for UV, Visible and IR applications using proprietary “grind and shine” techniques to produce low scatter surfaces. Whether to prepare lens surfaces or to correct wedge, CNC machine tools are employed throughout the spherical fabrication process.
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Based on Form Error Tolerance
Attribute |
Minimum |
Maximum |
| Diameter (mm) | 3 | 400 |
| Radius (mm) | ±1 | ∞2 |
| Aspect Ratio (Diameter/Center Thickness) | <1:1 | 30:1 |
| Included Angle (°) | 0 | 2103 |
Based on Form Error Tolerance
Form Error > 2μm Lower Resolution Profilometry (2-D)1 |
||
|---|---|---|
Attribute |
Minimum |
Maximum |
| Diameter (mm) | 3 | 250 |
| Local Radius (mm) | -8 (Concave) | ∞ |
| Sag (mm) | 0 | 502 |
| Departure (mm) | 0.01 | 20 |
| Included Angle (°) | 0 | 120 |
Form Error 0.5 – 2μm Higher Resolution Profilometry (2-D)1 |
||
Attribute |
Minimum |
Maximum |
| Diameter (mm)3 | 3 | 250 |
| Local Radius (mm) | -12 (Concave) | ∞ |
| Sag (mm) | 0 | 252 |
| Departure (mm) | 0.01 | 20 |
| Included Angle (°) | 0 | 150 |
Form Error < 0.5μm Interferometry with Stitching (3-D) |
||
Attribute |
Minimum |
Maximum |
| Diameter (mm)3 | 3 | 250 |
| Local Radius (mm) | -13 (Concave) | ∞ |
| Sag (mm) | 0 | 252,4 |
| Departure (mm) | 0.002 | 1 |
| Included Angle (°) | 0 | 120+5 |
Attribute |
Minimum |
Maximum |
| Diameter | 3mm | 500mm |
| Wavelength | 193nm | 6000nm |
| Use Environment | Vacuum | >95% RH |
| Durability | Moderate abrasion | Severe abrasion |
| Measurement | — | 68°, s, p, average polarization |
| Laser Damage Threshold | — | 1064nm: >30J/cm2@10ns, >1MW/cm2CW |
| Layers | 1 | 200 |
Rod or Arbor |
||
|---|---|---|
Attribute |
Minimum |
Maximum |
| Length (mm) | 3 | 5001 |
| Width (mm) Radius dependent | 2 | < 2x Radius |
| Cylinder Radius (mm) – Convex Only | 2 | 150 |
X-Y |
||
| Attribute | Minimum | Maximum |
| Length (mm) | 3 | 300 |
| Width (mm) | 2 | 300 |
| Cylinder Radius (mm) | 10 | ∞ |
| Concave sag to flat (mm) | 0.1002 | =Radius |
Attribute |
Tolerancing Limit* |
| Diameter (mm) | +0, -0.010 |
| Center Thickness (mm) | ± 0.050 |
| Irregularity – Interferometry (HeNe fringes) |
0.1** |
| Irregularity – Profilometry (μm) | ±1.0 |
| Wedge Lens – ETD (mm) |
TBD |
| Surface Roughness (Å RMS) | 10 |
Attribute |
Minimum |
Maximum |
| Diameter (mm) | 3 | 300 |
| Thickness | 1 | 150 |
| Aspect Ratio1 | 1 | 502 |
Attribute |
Sphere Tolerancing Limit |
|---|---|
| Glass Quality (nd, vd) | Melt Rebalanced and Controlled |
| Diameter (mm) | +0, -0.010 |
| Center Thickness (mm)4 | ± 0.020 |
| Sag – Concave (mm) | ± 0.010 |
| Clear Aperture | 100%5 |
| Radius (mm)6 | ± 0.0025 or 1 HeNe fringe7 |
| Irregularity (HeNe fringes)8 | 0.059 |
| Wedge Lens – ETD (mm) | 0.00210 |
| Bevels – Face Width @ 45° (mm) | ± 0.0511 |
| Scratch – Dig (MIL-PRF-13830B)12 | <10 – 5 |
| Surface Roughness (Å RMS) | 313,14 |
Attribute |
Cylinder Tolerancing Limit |
|---|---|
| Glass Quality (nd, vd) | Melt Rebalanced and Controlled |
| Length and width (mm) | +0, -0.020 |
| Center Thickness (mm)3 | ± 0.020 |
| Sag – Concave (mm) | ± 0.020 |
| Clear Aperture | 100%4 |
| Radius5 | ± 0.1% or 3 HeNe fringes6 |
| Irregularity – Interferometry (HeNe fringes)7 | 0.18 |
| Irregularity – Profilometry (μm) | ± 0.5 |
| Plano Axis Wedge – ETD (mm) | 0.00512 |
| Cylinder Axis Decentration – TIR (mm)9 | 0.01010 |
| Axial Twist Angle (arcminutes) | 3 |
| Bevels – Face Width @ 45° (mm)11 | 0/0mm max |
| Scratch – Dig (MIL-PRF-13830B)12 | 10 – 5 |
| Surface Roughness (Å RMS)13 | 5 |
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 |
Attribute |
Asphere Tolerancing Limit |
|---|---|
| Glass Quality (nd, vd) | Melt Rebalanced and Controlled |
| Diameter (mm) | +0, -0.010 |
| Center Thickness (mm)6 | ± 0.010 |
| Sag – Concave (mm) | ± 0.010 |
| Clear Aperture | 100%7 |
| Vertex Radius8 | ± 0.1% or 3 HeNe fringes9 |
| Irregularity – Interferometry (HeNe fringes)10 | 0.111 |
| Irregularity – Profilometry (μm)10 | ± 0.5 |
| Wedge Lens – ETD (mm) | 0.00212 |
| Bevels – Face Width @ 45° (mm)13 | ± 0.05 |
| Scratch – Dig (MIL-PRF-13830B)14 | 10 – 5 |
| Surface Roughness (Å RMS)15 | 10 |
Here are manufacturing limits and tolerances specific to optical aspheres, prisms, cylinders and spheres. For more detailed information on any attribute, please contact sales@optimaxsi.com.
Optimax has one of the largest test plate libraries for making spheres. These test plates are certified to +/- 0.01% of radius. As required, Optimax can make test plates for special radii.
Optimax’s R&D department is continuously looking for ways to improve our fabrication process and produce higher quality optics. Our current research projects are designed to meet future market needs, such as:
For more information please see Optimax Innovation or contact sales@optimaxsi.com.
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