KERN OLM 170 Metallurgical Inversion Microscope, Reflected Light, LED, Trinocular

Inverse geometry for bulk solid-state analysis

In industrial materials testing, semiconductor inspection and foundry analysis, heavy, large-volume or asymmetrical samples present conventional upright microscope systems with insurmountable mechanical challenges. The KERN OLM 170 eliminates these limiting spatial constraints through its inverse (reversed) system architecture. The plan-achromatic objectives and the focusing mechanism are physically positioned beneath the large cross-table. This allows solid engine blocks, thick steel slabs or heavy printed circuit boards to be placed directly on the table without any height restrictions. In terms of process engineering, this reduces the preparation effort enormously: the workpiece need only be ground and polished to be absolutely flat on the underside to be examined under the microscope. The need for time-consuming plane-parallel alignment of the entire sample body with the optical axis is physically eliminated entirely.

Optoelectronics of the LED reflected-light illumination

In stark contrast to systems using thermal halogen lamps, the OLM 170 is based on state-of-the-art semiconductor physics. The system is equipped with a high-performance, coaxial 5-watt LED incident light source. The light-emitting diode emits a high-intensity, completely flicker-free and colour-neutral photon spectrum with an extremely low heat output. This cold light source prevents the thermal expansion of the microscope’s mechanical components (thermospatial drift) and protects heat-sensitive semiconductor wafers from thermomechanical stress. The coaxial incident light is precisely directed into the optical axis via a partially transparent beam splitter, passes through the objective as a condenser and is reflected directly into the tube system by the opaque metal surface.

Physical precision of the infinity optics

The metrological foundation of the OLM 170 is its infinity-corrected lens system (Infinity Optics). The light waves reflected by the solid-state sample leave the objective as parallel beams. Only a tube lens incorporated into the trinocular microscope head focuses these photons into a sharp, real intermediate image. The physical space occupied by the parallel radiation between the objective and the tube lens enables the distortion- and aberration-free integration of optical accessories, such as the supplied polarisation and analyser unit. The system remains completely free from induced chromatic aberrations or shifts in focal length.

Anisotropy detection and digital metrology

When observing highly polished metal sections under reflected light, directional light inevitably leads to severe reflections (glare). The OLM 170 overcomes this phenomenon with its integrated polarisation system. The polariser forces the light waves into a linear plane of oscillation, whilst the crossed analyser physically blocks diffuse specular reflections. This maximises phase contrast and makes stress-induced birefringence, microcracks and heterogeneous alloy boundaries visible. To document these structures metrologically, the microscope features a trinocular tube with a C-mount adapter pre-fitted at the rear. This enables the direct, co-axial attachment of a digital microscope camera, whilst an internal light splitter (20:80) allows simultaneous inspection through the eyepiece.

Technical details

• Optical system: Infinity-corrected (Infinity Optics)
• Microscope design: Inverted metallurgical microscope
• Illumination type: 5 W LED epi-illumination, continuously dimmable
• Tubus design: Trinocular, 45° inclination
• Light distribution: 20:80 (eyepiece : camera)
• Objectives: Planachromatic LWD (Long Working Distance) optics
• Standard magnifications: 5x, 10x, 20x, 50x (plan objectives)
• Eyepieces: HWF 10x / Ø 20 mm (with dioptre adjustment)
• Optical contrast enhancement: Includes polariser and analyser unit
• Focusing: Coaxial coarse and fine adjustment (minimum fine adjustment 0.002 mm)
• Camera output: Pre-fitted C-mount adapter on the rear of the unit
• Power supply: External mains adaptor (100–240 V)

Contents

• 1 x KERN OLM 170 metallurgical inverted microscope
• 4 x Planachromatic LWD objectives (5x, 10x, 20x, 50x)
• 2 x HWF 10x wide-field eyepieces
• 1 x Polarisation and analyser unit
• 1 x Pre-assembled C-mount adapter
• 1 x power supply unit (including country adaptor)
• 1 x dust cover
• 1 x Detailed operating instructions

Custom requirements & accessories

The trinocular optical path, featuring the pre-assembled C-mount adapter, makes the OLM 170 the ideal platform for digital metrology. To measure lengths, areas or angles in your polished surface photographs with pixel-level precision, we recommend combining it with a calibrated digital microscope camera (e.g. the KERN ODC series) and a suitable object micrometer. Please feel free to contact our procurement service at any time regarding the optoelectronic configuration of your measuring station.