Industrial Coaxial Light Sources: Application Fields and Working Principle

Industrial coaxial light sources are mainly applied in industrial scenarios that require eliminating surface reflections of objects, highlighting fine structures, or achieving high-precision detection, and are particularly suitable for the detection of flat and highly reflective materials.

Their main application fields include:

Electronic manufacturing industry: PCB circuit board trace detection, chip pin flatness detection, and component solder joint quality determination.

Semiconductor industry: Wafer surface scratch/defect detection, mark reading and appearance inspection of semiconductors after packaging.

Precision component detection: Detection of scratches, stains, and dimension measurement on the surface of metal/glass bearings, gears, lenses, etc.

LCD/OLED display industry: Screen pixel defect (bright spot/dark spot) detection, and surface cleanliness inspection of glass substrates.

Automotive component detection: Surface defect (such as burrs, dents) detection and assembly accuracy verification of automotive precision stamping parts and injection-molded parts.

Medical consumable detection: Appearance defect detection and dimension compliance detection of transparent/translucent consumables such as syringes and infusion tubes.

The core working principle of industrial coaxial light sources is to use a semi-transparent and semi-reflective mirror (beam splitter) to make the light source coaxial with the camera's optical path, eliminating surface reflections of the measured object while uniformly illuminating the details of the object.

The specific working process can be divided into 3 steps:

Light emission: The light emitted by LED beads or other light sources first irradiates vertically a semi-transparent and semi-reflective mirror placed at a 45° angle.

Optical path turning: The semi-transparent and semi-reflective mirror reflects the vertically incident light by 90°, making its direction completely consistent with the camera's shooting optical path (i.e., "coaxial"), and irradiates vertically on the surface of the measured object.

Imaging feedback: The reflected light from the object surface (without reflection interference, only carrying object detail information) returns along the original optical path, penetrates the semi-transparent and semi-reflective mirror, and then enters the camera lens, finally forming a clear detection image with low reflection.

The key advantage of this design is that it can avoid the specular reflection generated when light irradiates highly reflective objects (such as metal and glass) at a non-vertical angle, allowing the camera to more accurately capture details such as scratches, defects, and textures on the object surface.