Self-reference Michelson interference ranging probe

Abstract

The utility model discloses a self-reference Michelson interference ranging probe, which belongs to the technical field of displacement measurement and comprises a broadband light source, a beam splitter, an optical collimation module, a standard reference block, a beam splitter, a sample, a compensating plate, a reflector and a spectrograph. Light is transmitted in the optical fiber for a certain distance, passes through the beam splitter and then enters the optical collimation module; a lens group in the optical collimation module collimates divergent light emitted from the end face of the optical fiber into approximately parallel light with a small divergence angle, and the collimated parallel light penetrates through a standard reference block and then penetrates through a beam splitter to be incident on the surface of a sample; according to the utility model, the standard reference block is directly used as a length reference signal, so that the probe achieves the purpose of mapping synchronization, displacement measurement reference information is provided in real time, the structure is simple, the size is small, a larger working distance can be provided, actual feeding and discharging are facilitated, and the probability of collision damage is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to displacement measurement technical field more specifically, relate to a self reference's Michelson interferometer ranging probe. BACKGROUND

[0002] Michelson interferometer is utilized split amplitude method to produce double light beam to realize interference, and through adjusting the interferometer, equal thickness interference fringes can be produced, and also equal inclination interference fringes can be produced, and it is mainly used for length and refractive index measurement, if observing interference fringe to move a, it is M2's moving arm moving amount for λ / 2, and equivalent to the air film thickness change λ / 2 between M1 and M2.In modern physics and modern metrology technology, such as in the research of spectral line fine structure and the experiment of using light wave to calibrate standard meter, it has important application.

[0003] At present, interferometric ranging is widely used in precision displacement measurement field, and the precision interferometric measurement probe of Fabry-Perot cavity structure is usually very close to the sample, which brings great difficulty to installation and debugging, and in order to increase the working distance of the probe to the sample, the wavelength resolution of the spectrometer must be higher, the interferometer of Michelson structure can obtain a large working distance through light path design, and almost equal light path design can overcome the defects of Fabry-Perot cavity structure interferometer, and the working distance does not increase the requirement of wavelength resolution, and the two kinds of interferometers do not have fixed reference, which brings great inconvenience to initial displacement calibration and system drift detection, in order to overcome these shortcomings, it is usually necessary to increase the external He-Ne laser as a reference, which brings great challenge to the volume and cost of the equipment. UTILITY MODEL CONTENTS

[0004] 1. Technical problem to be solved

[0005] In view of the problems in the prior art, the utility model aims at providing a self reference's Michelson interferometer ranging probe, which aims at solving the problem that the interferometer itself does not have fixed reference in the prior art, which brings great inconvenience to initial displacement calibration and system drift detection, in order to overcome these shortcomings, it is usually necessary to increase the external He-Ne laser as a reference, which brings great challenge to the volume and cost of the equipment.

[0006] 2. Technical scheme

[0007] In order to solve the above problems, the utility model adopts the following technical scheme:

[0008] The utility model provides a kind of self-referencing Michelson interferometric distance measuring probe, including broadband light source, beam splitter, optical collimation module, standard reference block, light splitting sheet, sample, compensating sheet, mirror and spectrometer, the light emitted by the broadband light source, after coupling into optical fiber, light is transmitted in optical fiber a distance after passing through the beam splitter into the optical collimation module;The lens group in the optical collimation module is collimated into approximate parallel light with small divergence angle after the light emitted from optical fiber end face diverges;After collimated parallel light transmits the standard reference block, it is incident to the sample surface again by the light splitting sheet;Another part of collimated parallel light is reflected by the light splitting sheet, and is incident to the mirror again by the compensating sheet;Light is reflected on the upper and lower surfaces of the standard reference block, the mirror surface and the sample upper surface, and the phase of reflected light in different positions is different, and after a distance is transmitted, it is finally coupled into optical fiber again;After the light reflected on the surface of the standard reference block and other reflected light again pass through the beam splitter, it is transmitted to the spectrometer by optical fiber, and is collected and presented.

[0009] As a preferred scheme of the utility model, the optical path of light reflected on the upper and lower surfaces of the standard reference block, the mirror surface and the sample upper surface is different, so that the phase is different, and when the reflected light on different surfaces meets again in optical fiber, interference occurs.

[0010] As a preferred scheme of the utility model, the signal of interference specifically shows periodic oscillation of light intensity on wavelength axis.

[0011] 3. Beneficial effects

[0012] Compared with prior art, the utility model has the advantages that:

[0013] (1) In the scheme, the position measurement probe of Michelson interferometer structure has a standard reference block between optical collimation module and light splitting sheet, which also appears in the final signal, and by calibrating the thickness of the standard reference block in advance, the probe can be started without zeroing, and the standard reference block is directly used as length reference signal, so that the probe achieves the purpose of synchronous measurement, and real-time displacement measurement reference information is provided, the structure is simple and small in size, a larger working distance can be provided, and the probability of collision and damage is reduced during actual feeding and discharging. ACCURACY OF DRAWINGS

[0014] Figure 1 It is the optical path diagram of the utility model.

[0015] Explanation of reference numerals in the drawing:

[0016] 1, broadband light source; 2, beam splitter; 3, optical collimation module; 4, standard reference block; 5, light splitting sheet; 6, sample; 7, compensating sheet; 8, mirror; 9, spectrometer. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments, and all other embodiments obtained by those skilled in the art without creative labor based on the embodiments in the utility model belong to the protection scope of the utility model.

[0018] In the description of the utility model, it needs to be explained that the terms "upper", "lower", "inner", "outer", "top / bottom end" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as limiting the utility model. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0019] In the description of the utility model, it needs to be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "provided with", "sleeved / connected", "connected" and the like should be understood broadly, for example, "connected" can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium; can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0020] Embodiment:

[0021] Please refer to Figure 1 A self-referencing Michelson interferometric distance measuring probe, comprising a broadband light source 1, a beam splitter 2, an optical collimation module 3, a standard reference block 4, a beam splitter 5, a sample 6, a compensation plate 7, a mirror 8 and a spectrometer 9, the light emitted by the broadband light source 1 enters the optical fiber after being coupled by the optical fiber, and the light is transmitted in the optical fiber for a distance and enters the optical collimation module 3 after passing through the beam splitter 2; the lens group in the optical collimation module 3 collimates the divergent light emitted from the end face of the optical fiber into approximate parallel light with a small divergence angle, the collimated parallel light transmits through the standard reference block 4, and then transmits through the beam splitter 5 to be incident on the surface of the sample 6; another part of the collimated parallel light is reflected by the beam splitter 5, and then transmits through the compensation plate 7 to be incident on the mirror 8; the light is reflected on the upper and lower surfaces of the standard reference block 4, the surface of the mirror 8 and the upper surface of the sample 6, the reflected light at different positions is different in phase, and after being transmitted for a distance, is finally coupled into the optical fiber again; the reflected light on the surface of the standard reference block 4 and other reflected light transmit through the beam splitter 2 again, are transmitted to the spectrometer 9 by the optical fiber, and are collected and presented.

[0022] The optical paths of the reflected lights of the upper and lower surfaces of the standard reference block 4, the surface of the mirror 8 and the upper surface of the sample 6 are different, so the phases are different, and when the reflected lights of the different surfaces meet again in the optical fiber, interference occurs;

[0023] The specific characteristics of the interference signal are periodic oscillation of light intensity on the wavelength axis.

[0024] In the embodiment, the distance between the mirror 8 and the beam splitter 5 is fixed, so the thickness of the air layer between them is fixed, when the sample 6 moves relative to the probe, the thickness of the air layer between them changes, and the period of the interference signal also changes, the frequency of the interference signal is calculated by using the frequency domain analysis method, so that the real-time physical distance of the sample 6 to the probe is obtained.

[0025] Working principle: the light emitted by the broadband light source 1 enters the optical fiber after being coupled by the optical fiber, the light transmits in the optical fiber for a distance, enters the optical collimation module 3 after the beam splitter 2, the lens group in the optical collimation module 3 collimates the divergent light emitted from the end face of the optical fiber into approximately parallel light with small divergence angle, the collimated parallel light transmits through the standard reference block 4, then transmits through the beam splitter 5, and is incident on the surface of the sample 6, another part of the collimated parallel light is reflected by the beam splitter 5, and is incident on the reference mirror surface, the light is reflected on the upper and lower surfaces of the standard reference block 4, the surface of the mirror 8 and the upper surface of the sample 6, the phases of the reflected lights of different positions are different, after transmitting for a distance, the reflected lights are finally coupled into the optical fiber again, the reflected lights and the light reflected on the surface of the standard reference block 4 are coupled into the optical fiber again, then transmit through the beam splitter 2, and are transmitted to the spectrometer 9 by the optical fiber, and are collected and presented, because the optical paths of the different reflected lights are different, so the phases are different, when the reflected lights meet again in the optical fiber, interference occurs, the specific characteristics of the interference signal are periodic oscillation of light intensity on the wavelength axis, the distance between the mirror 8 and the beam splitter 5 is fixed, so the thickness of the air layer between them is fixed, when the sample 6 moves relative to the probe, the period of the interference signal also changes, the frequency of the interference signal is calculated by using the frequency domain analysis method, so that the real-time physical distance of the sample 6 to the probe is obtained.

[0026] The above only describes a preferred embodiment of the present application, but the protection scope of the present application is not limited to this, any skilled person in the technical field according to the technical scheme and improvement concept of the present application, equivalent replacement or change, should be covered in the protection scope of the present application.

Claims

1. A self-referenced Michelson interferometric distance measuring probe, comprising a broadband light source (1), a beam splitter (2), an optical collimation module (3), a standard reference block (4), a beam splitter plate (5), a sample (6), a compensating plate (7), a mirror (8) and a spectrometer (9), characterized in that: The light emitted by the broadband light source (1) enters the optical fiber after fiber coupling, and the light is transmitted in the optical fiber for a distance and enters the optical collimation module (3) after passing through the beam splitter (2); The lens group in the optical collimation module (3) collimates the divergent light emitted from the end face of the optical fiber into approximately parallel light with a small divergence angle, and the collimated parallel light transmits through the standard reference block (4) and then transmits through the beam splitter plate (5) to be incident on the surface of the sample (6); Another part of the collimated parallel light is reflected by the beam splitter plate (5) and then transmits through the compensating plate (7) to be incident on the mirror (8); The light is reflected on the upper and lower surfaces of the standard reference block (4), the surface of the mirror (8) and the upper surface of the sample (6), and the reflected light from different positions has different phases, and after being transmitted for a distance, it is finally coupled into the optical fiber again; The reflected light from the surface of the standard reference block (4) and other reflected light together transmits through the beam splitter (2) again and is transmitted by the optical fiber to the spectrometer (9) for collection and presentation.

2. A self-referenced Michelson interferometric distance measuring probe according to claim 1, characterized in that: The optical paths of the reflected light from the upper and lower surfaces of the standard reference block (4), the surface of the mirror (8) and the upper surface of the sample (6) are different, so the phases are different, and when the reflected light from different surfaces meets again in the optical fiber, interference occurs.

3. A self-referenced Michelson interferometric range-finding probe according to claim 2, wherein: The specific characteristics of the interference signal are periodic oscillations of light intensity on the wavelength axis.

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