Self-reference double-cavity interference ranging probe
By using a self-referenced dual-cavity interferometric ranging probe and constructing an optical path with a transparent reference plate and an optical collimator, the problem of lack of reference standard in the prior art is solved, and high-precision initial displacement calibration and real-time drift detection are achieved.
Patent Information
- Application Number
- CN202423165616.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-22
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2034-12-22
AI Technical Summary
The lack of a fixed reference standard in existing general-purpose interferometric probes makes initial displacement calibration and system drift detection inconvenient.
A self-referenced dual-cavity interferometric ranging probe is used. A fixed thickness reference is provided by a transparent reference plate. An optical path is constructed by an optical collimator and a beam splitter to realize that the light interferes in the optical fiber after being reflected from the sample surface. The distance is calculated by frequency domain analysis.
It achieves high-precision initial displacement calibration and real-time drift detection. The structure is simple, the system is rigid and stable, no external calibration system is required, and the calibration and measurement are synchronized.
Smart Images
Figure CN223610790U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to precision displacement measurement technical field more specifically, relate to a kind of double-cavity interferometric ranging probe of self-reference. BACKGROUND
[0002] Interferometric ranging is a kind of technology based on light wave superposition principle to realize ranging, when two lights satisfy the conditions of same frequency, same vibration direction and constant initial phase difference, the interference phenomenon occurs to the two lights, and the interference fringes of bright and dark alternation are generated in interference field, the synthesis light intensity is related to the optical path difference of two lights reaching a point, the light intensity of two lights and the wavelength of light wave, and the interference fringes are the locus of the same optical path difference point, by measuring the change of interference fringes, various physical quantities and geometric quantities related to medium refractive index and geometric path can be obtained, and then ranging and other measurement purposes are realized.
[0003] At present, interferometric ranging is widely applied in precision displacement measurement field, but most of the existing general interferometric measurement probe does not have fixed reference datum, which brings great inconvenience to initial displacement calibration and system drift detection, therefore, the utility model provides a kind of double-cavity interferometric ranging probe of self-reference. UTILITY MODEL CONTENT
[0004] 1. Technical problem to be solved
[0005] In view of the problems in the prior art, the utility model aims at providing a kind of double-cavity interferometric ranging probe of self-reference, to solve the problem that the general interferometric measurement probe in the prior art does not have fixed reference datum, which brings great inconvenience to initial displacement calibration and system drift detection.
[0006] 2. Technical scheme
[0007] To solve the above problems, the utility model adopts the following technical scheme:
[0008] A kind of double-cavity interferometric ranging probe of self-reference, including width light source, beam splitter, optical collimator, light-transmitting reference sheet, sample and spectrometer, the light emitted by the width light source is coupled into optical fiber after optical fiber coupling, and the light is transmitted in optical fiber for a distance after the beam splitter enters the optical collimator, the optical collimator collimates the divergent light emitted from the end face of optical fiber into approximate parallel light with small divergence angle, the parallel light after collimation transmits the light-transmitting reference sheet and is incident to the surface of the sample, and the light occurs partial reflection on three surfaces, and the reflected light is finally coupled into optical fiber after transmission for a distance, and the reflected light is collected and presented into the spectrometer again after the beam splitter is transmitted by optical fiber.
[0009] As a preferred scheme of the utility model, the optical collimator contains a lens group, and the optical collimator collimates the divergent light into approximate parallel light with a small divergence angle through the lens group.
[0010] As a preferred scheme of the utility model, after the light transmitted by the light-transmitting reference sheet is incident on the surface of the sample, the light is partially reflected on the upper and lower surfaces of the light-transmitting reference sheet and the upper surface of the sample.
[0011] As a preferred scheme of the utility model, the reflected light from the three different position surfaces of the upper and lower surfaces of the light-transmitting reference sheet and the upper surface of the sample is different in phase.
[0012] As a preferred scheme of the utility model, the optical path of the reflected light from different positions of the upper and lower surfaces of the light-transmitting reference sheet and the upper surface of the sample is different, so that the phases are different, and the reflected light of different optical paths meets again in the optical fiber and interferes.
[0013] 3. Beneficial effects
[0014] Compared with the prior art, the utility model has the advantages that:
[0015] (1) In the scheme, a standard thickness light-transmitting reference sheet is added in the detection light path, the thickness information of the standard thickness light-transmitting reference sheet after optical Fourier transform is used to provide higher precision calibration for the distance from the sample to the probe, the light-transmitting reference sheet has a thickness, provides a real-time thickness reference, and makes the analysis of the ranging result not dependent on the calibration system outside the probe, and the light-transmitting reference sheet with the thickness and the detection light are coaxial with the sample, so that the structure is simple and the system is stable in rigidity.
[0016] (2) In the scheme, the light-transmitting reference sheet with a certain thickness also appears in the final signal, and by calibrating the thickness of the light-transmitting reference sheet in advance, the probe can be directly used as a length reference signal without zeroing, and the probe can truly realize synchronous measurement. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 It is a front view of the utility model.
[0018] Explanation of reference numerals in the drawing:
[0019] 1, width light source; 2, beam splitter; 3, optical collimator; 4, light-transmitting reference sheet; 5, sample; 6, spectrometer. DETAILED DESCRIPTION
[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of the present application.
[0021] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom end" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.
[0022] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "provided with", "sleeved / connected", "connected" and the like should be understood in a broad sense. 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 between two elements inside. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.
[0023] Embodiment:
[0024] Please refer to Figure 1 A self-referencing dual-cavity interferometric distance measuring probe, comprising a broadband light source 1, a beam splitter 2, an optical collimator 3, a light-transmitting reference sheet 4, a sample 5 and a spectrometer 6. The light emitted by the broadband light source 1 is coupled into the optical fiber after fiber coupling, and the light is transmitted in the optical fiber for a distance, then passes through the beam splitter 2 into the optical collimator 3. The optical collimator 3 collimates the divergent light emitted from the end face of the optical fiber into approximately parallel light with a small divergence angle. The collimated parallel light transmits through the light-transmitting reference sheet 4 and is incident on the surface of the sample 5. The light is partially reflected at the three surfaces, and the reflected light is finally coupled into the optical fiber again after being transmitted for a distance. The reflected light is transmitted to the spectrometer 6 through the beam splitter 2 again, collected and presented.
[0025] In the embodiment, the light source of the width light source 1 is sequentially transmitted through the beam splitter 2, the optical collimator 3 and the light-transmitting reference sheet 4 to be incident on the sample surface. The light-transmitting reference sheet 4 has a certain thickness, which also appears in the final signal. By calibrating the thickness of the light-transmitting reference sheet 4 in advance, the probe can be directly used as a length reference signal without zeroing, and the probe can truly realize synchronous measurement.
[0026] Specifically, the optical collimator 3 contains a lens group, and the optical collimator 3 collimates the divergent light into approximately parallel light with a small divergence angle through the lens group.
[0027] In the embodiment, the lens group is a composite optical element composed of multiple lenses, which is mainly used for controlling and changing the propagation path of light to realize specific optical functions.
[0028] Specifically, after the light transmitted by the light-transmitting reference sheet 4 is incident on the surface of the sample 5, the light is partially reflected on the upper and lower surfaces of the light-transmitting reference sheet 4 and the upper surface of the sample 5.
[0029] In the embodiment, the three reflection positions of the upper and lower surfaces of the light-transmitting reference sheet 4 and the upper surface of the sample 5 are different, so the optical paths are different.
[0030] Specifically, the reflection light phases of the three different positions of the upper and lower surfaces of the light-transmitting reference sheet 4 and the upper surface of the sample 5 are different.
[0031] In the embodiment, the reflection light phases of the three different positions are different, and after being transmitted for a distance, the reflection light is finally coupled into the optical fiber again.
[0032] Specifically, the optical paths of the reflection light of the different positions of the upper and lower surfaces of the light-transmitting reference sheet 4 and the upper surface of the sample 5 are different, so the phases are different. The reflection light of different optical paths meets again in the optical fiber and interference occurs.
[0033] In the embodiment, the specific characteristic of the interference signal is that the wavelength axis appears periodic oscillation of light intensity. When the thickness of the air layer between the sample 5 and the light-transmitting reference sheet 4 changes, the period of the interference signal also changes. The frequency domain analysis method is used to calculate the frequency of the interference signal, so as to obtain the physical distance from the sample 5 to the probe.
[0034] Working principle: the light emitted by the width light source 1 enters the optical fiber after fiber coupling, the light is transmitted in the optical fiber for a distance, enters the optical collimator 3 after the beam splitter 2, the lens group in the optical collimator 3 collimates the divergent light emitted from the optical fiber end face into approximate parallel light with small divergence angle, the parallel light after collimation transmits the light transmission reference sheet 4, and is incident on the surface of the sample 5, the light is partially reflected on the upper and lower surfaces of the light transmission reference sheet 4 and the upper surface of the sample 5, the reflected light at different positions has different phases, is transmitted for a distance, and is finally coupled into the optical fiber again, the reflected light is transmitted to the spectrometer 6 in the optical fiber again after the beam splitter 2, is collected and presented, due to the different optical paths of different reflected light, the phases are different, when they meet again in the optical fiber, interference occurs, the specific characteristics of the interference signal is that the periodic oscillation of light intensity appears on the wavelength axis, when the air layer thickness between the sample 5 and the light transmission reference sheet 4 changes, the period of the interference signal also changes, the frequency domain analysis method is used to calculate the frequency of the interference signal, so that the physical distance from the sample 5 to the probe is obtained.
[0035] The above merely describes a preferred specific 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 should be covered in the protection scope of the present application.
Claims
1. A self-referenced dual cavity interferometric range finder probe comprising a broadband light source (1), a beam splitter (2), an optical collimator (3), a transparent reference plate (4), a sample (5) and a spectrometer (6), characterized in that: The light emitted by the wide light source (1) enters the optical fiber after fiber coupling, and the light is transmitted in the optical fiber for a distance, then enters the optical collimator (3) through the beam splitter (2), the optical collimator (3) collimates the divergent light emitted from the end face of the optical fiber into approximately parallel light with a small divergence angle, the collimated parallel light transmits the light-transmitting reference sheet (4) and is incident on the surface of the sample (5), the light is partially reflected at the three surfaces, the reflected light is finally coupled into the optical fiber after being transmitted for a distance, and the reflected light is transmitted to the spectrometer (6) by the optical fiber again through the beam splitter (2), collected and presented.
2. A self-referenced dual-cavity interferometric range-finding probe according to claim 1, characterized in that: The optical collimator (3) contains a lens group, and the optical collimator (3) collimates the divergent light into approximately parallel light with a small divergence angle through the lens group.
3. A self-referenced dual-cavity interferometric range-finding probe according to claim 2, wherein: After the light transmitted by the light-transmitting reference sheet (4) is incident on the surface of the sample (5), the light is partially reflected at the upper and lower surfaces of the light-transmitting reference sheet (4) and the upper surface of the sample (5).
4. A self-referenced dual-cavity interferometric range-finding probe according to claim 3, wherein: The reflected light from the three different position surfaces of the upper and lower surfaces of the light-transmitting reference sheet (4) and the upper surface of the sample (5) is different in phase.
5. A self-referenced dual-cavity interferometric range-finding probe according to claim 4, wherein: The optical path of the reflected light from different positions of the upper and lower surfaces of the light-transmitting reference sheet (4) and the upper surface of the sample (5) is different, so the phases are different, and the reflected light with different optical paths will interfere when they meet again in the optical fiber.