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Machine Vision
Coaxial

A coaxial LED lighting emits a diffused light in the axis of the camera. The light is reflected on a half mirror which directs it towards the workpiece. The light from specular reflection is reflected on the camera, while the diffuse light reflected from the target will be blocked.
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Learn more about our coaxial lightings

Coaxial lighting is a machine vision illumination technique where the light is aligned with the optical axis of the camera.

It works using a semi-transparent mirror (beam splitter) that redirects the light toward the object while allowing the reflected light to pass back to the camera.

This configuration creates a very controlled lighting effect:

  • flat and reflective surfaces return light directly to the camera → appear bright
  • surface defects (scratches, engravings, contamination) scatter light → appear dark

This contrast mechanism makes coaxial lighting highly effective for surface inspection applications.
Coaxial lighting is particularly well suited for applications involving flat, smooth, or highly reflective surfaces.

Typical use cases include:

  • PCB and electronic component inspection
  • semiconductor and wafer inspection
  • inspection of polished metal or glass surfaces
  • detection of engraving, markings, or fine defects
  • surface quality control and precision inspection

It is widely used when traditional lighting creates glare or unstable reflections that hide defects.
Coaxial lighting offers several advantages compared to more common lighting solutions:

  • perfect alignment with the camera axis for controlled illumination
  • uniform brightness on flat reflective surfaces
  • reduction of glare and unwanted reflections
  • enhanced visibility of fine defects
  • high contrast between surface and imperfections

Compared to solutions like ring lights:

  • ring lights illuminate from multiple angles → more general-purpose
  • coaxial lighting provides on-axis illumination, ideal for reflective and flat surfaces

This makes coaxial lighting the preferred choice for high-precision surface inspection.
Coaxial lighting systems are generally compatible with standard industrial cameras.

They are typically integrated:

  • directly along the optical axis of the camera
  • or combined with specific optical setups (lens + beam splitter)

Because coaxial lighting relies on precise alignment, proper mechanical integration is essential for optimal performance. When correctly implemented, these systems can be easily used with most machine vision cameras.
EFFI-COAX
Coaxial lighting for surface inspection
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