Method and system for automatically positioning laser focusing position

Abstract

The invention is suitable for the technical field of detection, and provides a laser focusing position automatic positioning method and system, the relative distance between a laser focusing lens and the surface of a sample is adjusted, a laser focusing point is located on the surface of the sample, and focusing position information corresponding to the laser focusing point at the moment is recorded; projecting a reference point light spot to the surface of the sample, and acquiring reference position information of the reference point light spot; according to the focusing position information and the reference position information, the height position of the sample platform is automatically adjusted, the reference position of the reference point light spot is moved to the focusing position corresponding to the laser focusing point, and sample surface component information on the same cross section as the reference point is detected. The method is suitable for fast and automatic positioning of the laser focusing position in the LIBS system when samples with different thicknesses are detected. The device is simple in structure and high in universality, laser pulses in an LIBS system can be quickly, accurately and automatically focused on the surface of a sample, and the stability of spectral signals and the reliability and accuracy of detection precision are improved.

Description

technical field [0001] The invention belongs to the technical field of detection, and in particular relates to an automatic positioning method and system for a laser focus position. Background technique [0002] Laser-induced breakdown spectroscopy (LIBS) technology is an atomic emission spectroscopy technique. By focusing high-energy pulsed laser on the surface of the sample, ablation excites the sample to generate plasma, and then according to the collected plasma spectrum, it can be Qualitative and quantitative analysis of the elements contained in the sample. This technology has the advantages of no need for complicated sample pretreatment, strong adaptability to the environment, rapid analysis of multiple elements at the same time, remote analysis, and in-situ online real-time analysis. Oil and gas resource exploration and other fields have become a research hotspot in the field of compositional analysis. [0003] Chinese patent application publication number CN113740...

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Problems solved by technology

[0003] Chinese patent application publication number CN113740316A discloses a method and system for automatic positioning of the laser focus point based on the position of the spot. In this patent, the spatial coordinate geometric relationship between the laser focus point and the spot after placing the sample is used to obtain the The distance required to move the sample surface to the guide rail at the laser focus point. Two-dimensional coordinates are used in the spatial coordinate geometric relationship. According to the spatial geometric relationship, the sample needs to have good flatness in the two-dimensional direction, that is, the sample surface is required Flatness, the flatness of the sample to be tested is high; and the indicating laser is obliquely incident, and the slight deviation of the incident angle of the indicating laser will also have a great impact on the positioning of the focus position

[0004] When LIBS equipment is used to detect the composition of raw or compressed samples such as renewable metal recovery materials, mineral raw materials, high-temperature melt sampling materials, etc., due to the difference in thickness between the same batch or several batches of samples to be tested, the laser in the LIBS equipment will The relative distance between the focusing lens and the sample surface is inaccurate. If it is not adjusted in time, it will directly affect the stability and accuracy of the measurement results of LIBS equipment.

Traditional methods such as manual indicator light adjustment, sample surface imaging definition adjustment, and laser rangefinder adjustment are easily affected by sample characteristics such as surface granularity, surface gloss, sensitivity of equipment used, and proficiency in human operation. The adjustment speed is slow, which is not conducive to the rapid and automatic positioning of the laser focus position

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