Linear dispersion objective lens

Abstract

The invention provides a linear dispersion objective lens. Axial dispersion and the wave length approximately form a linear relation within the wavelength range from light F to light C. The linear dispersion objective lens has large dispersion, long working distance and small spherical aberration. The linear dispersion objective lens is composed of a positive lens assembly and a negative lens assembly, wherein the negative lens assembly is close to a needle hole and integrally has negative power, and the positive lens assembly is close to an object and integrally has the positive power. The surface, closest to the object, of the objective lens is a concave face, and the materials of the positive lens assembly and the materials of the negative lens assembly meet the certain dispersion correcting relation. The linear dispersion objective lens can provide large design freedom degree, is used for a spectrum confocal device, effectively improves the whole performance of the device, and is mainly applied to detection of displacement, the transparent element thickness, the micro three-dimensional structure and surface roughness and the like.

Description

technical field [0001] The invention belongs to the technical field of objective lenses, and in particular relates to a linear dispersion objective lens. The invention can be used in spectral confocal displacement sensors, spectral confocal microscopes and other devices using spectral confocal technology (Chromatic Confocal Technology), and is suitable for detection of displacement, thickness of transparent components, three-dimensional structure, surface topography and the like. Background technique [0002] Ordinary microscope objectives require the elimination of chromatic aberration, which can be achieved through a combination of various glasses. The dispersion objective lens used in spectral confocal technology is just the opposite, requiring as large aberration (dispersion) as possible to increase the detection range, usually using high dispersion glass to achieve this goal (Optoelectronic Engineering, 2011, 28(7): 131- 135). However, the linearity between the disper...

AI Technical Summary

Problems solved by technology

However, this method can only achieve a linear relationship between dispersion and wavelength between tightly coupled lenses. It is not suitable for dispersion objectives that require a large air gap and multi-stage magnification. The degree of freedom in design is small and the practicability is low.

The applicant once designed a practical dispersion objective lens based on this principle, but the structure of the objective lens is relatively complex and the overall length is relatively large (Optical Precision Engineering, 2013, 21(10): 2473-2479)

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