An APO lens (apochromatic lens) delivers higher resolution, lower color sensitivity, and significantly enhanced contrast compared with standard achromatic lenses. APO lenses are widely used in high-end imaging, machine vision, metrology, and line-scan inspection systems, where color accuracy and edge sharpness are critical.
What Is an APO (Apochromatic) Lens?
An apochromatic lens is an advanced optical design that corrects chromatic aberration and spherical aberration more thoroughly than conventional achromatic lenses.
Understanding Chromatic Aberration
Chromatic aberration occurs because different wavelengths of light focus at different positions. In the visible spectrum, it is commonly evaluated by the focal difference between:
- F line (violet/blue light)
- C line (red light)
An achromatic lens corrects two wavelengths (typically red and blue), but leaves residual color error—known as the secondary spectrum—around the D line (green light).
How an APO Lens Improves Performance
By carefully selecting special optical glass materials and optimizing multi-element lens groups with precise curvature, an APO lens:
- Brings F (blue), D (green), and C (red) wavelengths to the same focal plane
- Eliminates the secondary spectrum
- Limits focal length variation across wavelengths to less than 1/2000 of the focal length
This results in:
- Exceptional color fidelity
- Superior edge sharpness
- Higher contrast and resolution
- Minimal color fringing, even at high magnification
Why Choose an APO Lens?
APO lenses are ideal for applications requiring:
- Ultra-high resolution imaging
- Sub-pixel accuracy
- High-speed line scan inspection
- Large sensor coverage
- Consistent performance across the full visible spectrum
Typical applications include:
- Semiconductor inspection
- Flat panel display (FPD) inspection
- Precision metrology
- Industrial automation
- High-resolution machine vision
How to Select an APO Lens
When selecting an apochromatic lens, consider the following key parameters:
- Sensor Size & Resolution: Ensure the lens supports your camera format (e.g. 8K / 16K line scan, 3.5 μm or 5 μm pixel size).
- Magnification Range: Match lens magnification to your field-of-view and inspection accuracy requirements.
- Chromatic Performance: APO lenses are essential when color misalignment directly affects measurement accuracy.
- Mount & Mechanical Design: Consider mount type, flange distance adjustment, and compactness for system integration.
- Working Distance & Aperture: Select appropriate EFL and iris range for lighting conditions and depth of field.
Shape Optics APO Line Scan Lens Portfolio
Shape Optics Technologies offers 8K and 16K APO line scan lenses designed for high-precision industrial inspection systems.
Key Features
- Magnification coverage from 0.2× to 6.2×
- Supports Ø88 mm large-format sensors
- Compatible with 8K & 16K line scan cameras (3.5 μm / 5 μm pixels)
- Compact F-mount full-flange design
- Threaded barrel with adjustable flange distance
- Optimized for high contrast and ultra-low chromatic aberration
16K Apochromatic Line Scan Lens Series
| Model | Central Mag. | EFL | Mag. Range | Image Format | Iris | Mount |
|---|---|---|---|---|---|---|
| SOTPLS16437APO | 4.37 | 116.0 mm | 3.80–4.80 | φ88 mm | F1.6–F16 | M90 / M95 |
| SOTPLS16620APO | 6.20 | 116.7 mm | 5.60–6.90 | φ88 mm | F1.6–F16 | M90 / M95 |
| SOTLS16030APO | 0.32 | 115.0 mm | 0.29–0.34 | φ62 mm | F3.8–F16 | M58 / M72 / M90 |
| SOTLS16070APO | 0.70 | 112.0 mm | 0.65–0.76 | φ80 mm | F3.6–F16 | M58 / M72 / M90 |
8K Apochromatic Line Scan Lens Series
| Model | Central Mag. | EFL | Mag. Range | Sensor Size | Iris | Mount |
|---|---|---|---|---|---|---|
| SOTLS80014APO | 0.14 | 80 mm | 0.13–0.166 | φ64 mm | F5.6–F22 | M58 / M72 / M90 |
| SOTLS80021APO | 0.21 | 80 mm | 0.18–0.24 | φ64 mm | F5.6–F22 | M42 / M58 / M72 |