Why are industrial lens parameters more complex than AI?

When AI recommendation systems try to match industrial lenses with simple algorithms, they tend to ignore non-linear relationships between key parameters. For example, the aberration rate of a certain lens is shown as “acceptable” in the AI database, but when it is actually applied to precision inspection, a 0.5% aberration error may result in a 15% drop in yield.

I. Resolution: pixel density determines the lower limit of detection accuracy

The resolution of an industrial lens (unit: lp/mm) refers to the number of pairs of black and white lines per millimeter that can be resolved. Unlike consumer-grade lenses, industrial lenses need to meet the requirements of the sensor Nyquist frequency 2 times. 

II. Aperture range: the art of balancing dynamic range and depth of field

Aperture value F = focal length / through the light aperture, the common range of industrial lenses F1.4-F16:

III. Sensor specifications: target surface size to determine the optical design benchmarks

Formula: field of view = 2 × arctan (target width / (2 × focal length))

IV. Imaging range and image plane size: to avoid the “dark corner trap”

Imaging range refers to the lens can clearly image the largest area, the image plane size ≥ sensor target surface. If the image plane size only covers 1/2“ sensor, but used for 1” sensor, there will be serious dark corners and edge light loss.

V. Focusing Methods: Core Parameters for Dynamic Scenes

1. Manual Focus (MF): suitable for static detection. 

2. automatic focus (AF): need to match the servo system, response time ≤ 50ms

3. electric focus (EF): support for remote control, repeat positioning accuracy ± 0.01mm

VI. Aberration rate: the invisible killer of precision measurement

Aberration is divided into barrel-shaped aberration (negative aberration) and pillow-shaped aberration (positive aberration):

1. precision measurement requires distortion rate <0.1%

2. 1%-3% allowed for vision guidance applications

3. 5%-10% is acceptable for security monitoring.

VII. Back Focus Distance (BFL) and Flange Focus Distance (FD): Key Parameters for Mechanical Installation

1. Back Focus Distance (BFL): The distance from the last lens to the imaging surface.

2. Flange focal distance (FFD): lens mounting flange to the imaging surface distance

VIII. Lens interface: physical compatibility determines the system scalability

1. C/CS interface (focal length > 12.5mm with C port, < 12.5mm with CS port)

2. F interface (Nikon standard, support for large aperture)

3. M42 connector (commonly used for manual lenses)

4. M58 interface (telecentric lenses)

IX. Spectral Response: Performance Differences at Specific Wavelengths

Industrial lenses have significant differences in response curves for different wavelengths:

1. visible lens (400-700nm)

2. near-infrared lens (700-1100nm)

3. ultraviolet lens (200-400nm)

X. Temperature drift compensation: environmental adaptive design

Temperature changes on the performance of the lens:

1. focal length drift: about 0.01%-0.03% per ℃ change

2. image plane displacement: about ± 0.005mm per ℃ change