Nikon LU Plan ELWD 20x Brightfield Darkfield Objective

The Nikon LU Plan ELWD 20× Brightfield Darkfield Objective (MUE60201) is a workhorse industrial objective designed for reflected light microscopy of opaque materials including metals, semiconductors, ceramics, and engineered surfaces. This objective is distinguished by its exceptional 13mm working distance—among the longest available for a 20× objective—combined with dual illumination capability, enabling examination of challenging specimens that would be impossible to inspect with standard working distance objectives.

The 20× magnification and 0.40 numerical aperture provide an optimal balance between field of view and resolving power, making this objective ideal for initial specimen survey, feature location, and general-purpose inspection work. This magnification is particularly valuable in quality control environments where operators need to quickly scan larger areas while maintaining sufficient resolution to identify defects, measure features, and characterize surface conditions.

The 13mm extra-long working distance is the defining feature of this objective, providing unprecedented clearance for industrial microscopy applications. This extended working distance enables examination of thick specimens or samples mounted in fixtures, rough or highly textured surfaces with significant topographical variation, tilted or angled specimens requiring oblique viewing, samples requiring manipulation or probing during observation, and specimens in environmental chambers or specialized holders. The generous clearance also provides protective margin that reduces the risk of objective damage from accidental contact—a common concern in production environments where operators work quickly or examine irregularly shaped parts.

The objective supports both brightfield and darkfield illumination modes, offering versatile imaging capabilities in a single lens. Brightfield mode provides conventional reflected light imaging ideal for examining polished surfaces, grain structure, and phase composition in metallographic samples. Darkfield mode enhances contrast for surface features, scratches, cracks, and topographical variations by illuminating the sample at oblique angles. This dual capability eliminates the need to switch objectives when changing illumination modes, improving workflow efficiency.

The LU Plan (Long-distance Universal Plan) optical design delivers flat-field correction across the entire field of view, ensuring sharp focus from center to edge. This is essential for accurate measurement and documentation, as it eliminates the need to refocus when examining features at different positions in the field. The infinity-corrected design enables integration with tube lenses, beam splitters, camera systems, and other optical accessories without introducing aberrations.

The M32 thread mount is compatible with Nikon industrial microscopes featuring BD (brightfield/darkfield) nosepieces, including the Eclipse LV series and Epiphot series.

This unit is in excellent, like-new pre-owned condition, ready for demanding industrial inspection and materials analysis applications.