Shielding type dark field confocal subsurface nondestructive testing equipment

Abstract

The utility model relates to the technical field of subsurface nondestructive testing equipment, and discloses shielding type dark field confocal subsurface nondestructive testing equipment which comprises a base. According to the shielding type dark field confocal subsurface nondestructive testing equipment, through the arrangement of the annular light shaping mechanism, the spatial light isolation mechanism and the scanning mechanism, when the equipment is used, double light beams firstly pass through a reflective collimating mirror to be collimated into approximately parallel light, and then pass through a polaroid, the polaroid is adjusted to enable the double light beams to be P light; light beam shaping is completed after the detection light beam passes through a back-to-back biconical lens group to form annular high-frequency illumination light, the shaped annular detection light is transmitted and passes through a dichroscope, pump light firstly passes through a reflector D, and incident light is reflected through the dichroscope; the double light beams are coaxial after passing through the dichroscope, then are changed into right-handed circularly polarized light after passing through the spatial light isolation mechanism, enter the objective lens through the galvanometer, the scanning lens and the tube lens, and are irradiated on a sample.

Description

Technical Field

[0001] The utility model relates to the technical field of shielded dark field confocal sub-surface non-destructive testing equipment, in particular to shielded dark field confocal sub-surface non-destructive testing equipment. Background Art

[0002] Optical materials are functional materials with specific optical properties. With the continuous advancement of materials science and processing technology, they have been widely used in the production of key components in various fields. These materials mainly include optical glass and optical crystals, which play an important role in industry, military and scientific research. The production of optical components usually requires multiple process steps, usually including cutting, grinding, lapping and polishing. During these processes, it is inevitable to exert a certain amount of pressure on the surface of the optical component, resulting in sub-surface damage. The currently widely used light scattering method and photothermal detection technology have the problem that it is not easy to take into account the sensitivity, resolution and axial positioning accuracy for the detection of sub-surface absorption defects, and it is not easy to achieve effective detection of absorption defects.

[0003] At present, the shielded dark field confocal sub-surface non-destructive testing equipment on the market has the following disadvantages:

[0004] (1) Photothermal microscopy is a widely used photothermal detection technology for detecting nanoscale defects in optical materials. However, the sensitivity of this technology to scattered signals determines that it is only suitable for interference with tiny damage. In addition, the complexity of the laser scattering field will cause the sub-surface damage signal to be easily interfered by the component surface and scattered signals, so it is mostly used for qualitative analysis.

[0005] (2) Photothermal deflection technology has many advantages, such as high sensitivity, simple experimental equipment, easy implementation, ability to distinguish between volume absorption and surface absorption, and non-contact detection of highly corrosive samples. However, it is highly dependent on the environment and difficult to debug. Therefore, the surface thermal lens method is more widely used in mainstream commercial instruments.

[0006] (3) Thermal lens technology is widely used in absorption-type defect detection of optical components due to its advantages such as high resolution, simple optical path adjustment, high measurement sensitivity and good repeatability. However, the current surface thermal lens photothermal detection technology has problems such as low lateral resolution and low axial defect positioning accuracy. At present, magnetorheological polishing technology is widely used in optical components. Magnetorheological polishing has high processing accuracy and is not easy to cause secondary sub-surface defects, but it also has problems such as slow processing speed and low removal efficiency. Utility Model Content

[0007] 1. Technical issues to be resolved

[0008] The technical problem solved by the utility model is to provide a shielded dark field confocal sub-surface non-destructive testing device which is highly practical, can be simply operated and has a relatively simple structure, thereby solving the problem of difficulty in balancing sensitivity, resolution and axial positioning accuracy raised in the above-mentioned background technology.

[0009] (II) Technical solution

[0010] To achieve the above objectives, the utility model is implemented through the following technical solutions: a shielded dark field confocal sub-surface non-destructive testing equipment, including a base, one side of the surface of the base is conveniently fixedly connected with an objective lens, one side of the objective lens is fixedly connected with a scanning mechanism, one side of the scanning mechanism is fixedly connected with a spatial light isolation mechanism, one side of the spatial light isolation mechanism is fixedly connected with a detection mechanism, the other side of the spatial light isolation mechanism is fixedly connected with a dichroic mirror, one side of the dichroic mirror is fixedly connected with an annular light shaping mechanism, the other side of the dichroic mirror is fixedly connected with a reflector D, the back of the reflector D is fixedly connected with a polarizer B, and the back of the polarizer B is fixedly connected with a reflective collimator B.

[0011] As a further solution of the utility model, the scanning mechanism includes a tube lens fixedly connected to one side of the objective lens, one side of the tube lens is fixedly connected to a reflector A, the front of the reflector A is fixedly connected to a scanning lens, and the front of the scanning lens is fixedly connected to a galvanometer mirror, which is convenient for changing the direction of the light beam by vibration.

[0012] As a further solution of the utility model, the spatial light isolation mechanism includes a quarter glass slide fixedly connected to one side of the scanning mechanism, one side of the quarter glass slide is fixedly connected to a PBS, the front of the PBS is fixedly connected to a reflector B, one side of the PBS is fixedly connected to a reflector C, the back of the reflector C is fixedly connected to an aperture body, and one side of the reflector B is fixedly connected to an aperture and a collecting lens module. The aperture and the collecting lens module are used to facilitate the removal of reflected light of the detection beam, leaving the diffraction signal generated by the photothermal effect and the scattering signal of the pump light and the detection light.

[0013] As a further solution of the utility model, the detection mechanism includes a pinhole fixedly connected to one side of the spatial light isolation mechanism, one side of the pinhole is electrically connected to a photodetector, one side of the photodetector is electrically connected to a phase-locked amplifier through a power line, and the phase-locked amplifier facilitates improving the signal-to-noise ratio.

[0014] As a further solution of the utility model, the annular shaping mechanism includes a back-to-back biconical lens group fixedly connected to one side of the dichroic mirror, a polarizer A is fixedly connected to the back of one side of the back-to-back biconical lens group, and a reflective collimator A is fixedly connected to the back of the polarizer A, which facilitates the passage of laser.

[0015] As a further solution of the utility model, a collimator body is fixedly connected to the inside of the pinhole, a filter is fixedly connected to one side of the collimator body, and a collecting lens body is fixedly connected to one side of the filter. The collecting lens body is convenient for collecting light of a specific wavelength.

[0016] As a further solution of the utility model, a plurality of threaded holes are provided on the surface of the base, and threaded columns are connected to the internal threads of the threaded holes, so that the threaded columns are convenient for fixing the optical instrument.

[0017] (III) Beneficial effects

[0018] The utility model provides a shielded dark field confocal sub-surface non-destructive testing device, which has the following

[0019] Beneficial effects:

[0020] 1. The shielded dark field confocal sub-surface non-destructive testing equipment is provided with an annular light shaping mechanism, a spatial light isolation mechanism and a scanning mechanism. When in use, the double light beams are first collimated by a reflective collimator to become approximately parallel light, and then pass through a polarizer after collimation. The polarizer is adjusted to make the double light beams P light, and then the detection light beam passes through a back-to-back biconical lens group to complete the beam shaping to form an annular high-frequency illumination light. The shaped annular detection light is transmitted through a dichroic mirror, and the pump light first passes through a reflector D, and the incident light is reflected by the dichroic mirror; the double light beams realize beam coaxiality after passing through the dichroic mirror, and then pass through a spatial light isolation mechanism together to make them become right-handed circularly polarized light, and then enter the objective lens through a galvanometer, a scanning lens and a tube lens to irradiate the sample.

[0021] 2. The shielded dark field confocal sub-surface nondestructive testing equipment, through the setting of the detection mechanism, when in use, the reflected signal and diffracted photothermal signal of the detection light and pump light pass through the objective lens, tube lens, reflector A, scanning lens, and galvanometer in the opposite direction, and then pass through a quarter glass slide to become vertical linear polarized light, and then pass through the polarization beam splitter prism to become reflected and emitted, and then pass through the reflector B to enter the aperture and collection lens module, and then the diffraction and scattering signals of the detection light beam and the scattering signals of the pump light are collected by the pinhole after being converged by the aperture and the collection lens module. The collected signals also include the reflected light of the pump light, so they are connected to the detection module via optical fiber, connected to the reflective collimator and emitted in parallel, and enter the filter, whose function is to filter out the pump light. Then, the light is focused through the collecting lens body and enters the pinhole. The photomultiplier tube converts the optical signal into an electrical signal, which is then input into the phase-locked amplifier. It can demodulate the thermal wave signal according to the frequency of the photothermal signal and output a DC voltage signal. The amplitude of the DC signal can be used to characterize the thermal wave amplitude signal at that point, and the output phase signal can be used to characterize the thermal wave phase signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0023] Figure 2 This is a schematic diagram of the structure of the detection mechanism of the utility model;

[0024] Figure 3 This is a schematic diagram of the scanning mechanism structure of the utility model;

[0025] Figure 4 This is a schematic diagram of the structure of the annular light shaping mechanism of the utility model;

[0026] Figure 5 It is a schematic diagram of the structure of the spatial light isolation mechanism of the utility model.

[0027] In the figure: 1. base; 2. objective lens; 3. scanning mechanism; 301. tube lens; 302. reflector A; 303. scanning lens; 304. galvanometer; 4. spatial light isolation mechanism; 401. quarter glass slide; 402. PBS; 403. reflector B; 404. reflector C; 405. aperture body; 406. aperture and collecting lens module; 5. detection mechanism; 501. pinhole; 502. photodetector; 503. phase-locked amplifier; 6. dichroic mirror; 7. annular light shaping mechanism; 701. back-to-back biconical lens group; 702. polarizer A; 703. reflective collimator A; 8. reflector D; 9. polarizer B; 10. reflective collimator B; 11. collimator body; 12. filter; 13. collecting lens body; 14. threaded column. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0029] See also Figures 1 to 5The utility model provides a technical solution: a shielded dark field confocal sub-surface non-destructive testing device, comprising a base 1, one side of the surface of the base 1 is conveniently fixedly connected with an objective lens 2, one side of the objective lens 2 is fixedly connected with a scanning mechanism 3, through the setting of an annular light shaping mechanism 7, a spatial light isolation mechanism 4 and the scanning mechanism 3, a double beam of light is irradiated onto the sample, one side of the scanning mechanism 3 is fixedly connected with the spatial light isolation mechanism 4, one side of the spatial light isolation mechanism 4 is fixedly connected with a detection mechanism 5, through the setting of the detection mechanism 5, the amplitude of the DC signal can be used to characterize the thermal wave amplitude signal of the point, and the output phase signal can be used to characterize the thermal wave phase signal, the other side of the spatial light isolation mechanism 4 is fixedly connected with a dichroic mirror 6, one side of the dichroic mirror 6 is fixedly connected with an annular light shaping mechanism 7, the other side of the dichroic mirror 6 is fixedly connected with a reflector D8, the back of the reflector D8 is fixedly connected with a polarizer B9, and the back of the polarizer B9 is fixedly connected with a reflective collimator B10;

[0030] The scanning mechanism 3 includes a tube lens 301 fixedly connected to one side of the objective lens 2, a reflector A302 fixedly connected to one side of the tube lens 301, a scanning lens 303 fixedly connected to the front of the reflector A302, and a galvanometer 304 fixedly connected to the front of the scanning lens 303. The galvanometer 304 is arranged to change the direction of the light beam by vibration.

[0031] The spatial light isolation mechanism 4 includes a quarter glass slide 401 fixedly connected to one side of the scanning mechanism 3, a PBS 402 fixedly connected to one side of the quarter glass slide 401, a reflector B 403 fixedly connected to the front of the PBS 402, a reflector C 404 fixedly connected to one side of the PBS 402, a diaphragm body 405 fixedly connected to the back of the reflector C 404, and a diaphragm and a collecting lens module 406 fixedly connected to one side of the reflector B 403. The diaphragm and the collecting lens module 406 are arranged to remove the reflected light of the detection light beam, and retain the diffraction signal generated by the photothermal effect and the scattered signal of the pump light and the detection light.

[0032] The detection mechanism 5 includes a pinhole 501 fixedly connected to one side of the spatial light isolation mechanism 4, one side of the pinhole 501 is electrically connected to a photodetector 502, one side of the photodetector 502 is electrically connected to a lock-in amplifier 503 through a power line, and the setting of the lock-in amplifier 503 plays a role in improving the signal-to-noise ratio;

[0033] The annular light shaping mechanism 7 includes a back-to-back biconical lens group 701 fixedly connected to one side of the dichroic mirror 6, a polarizing plate A702 is fixedly connected to the back of one side of the back-to-back biconical lens group 701, and a reflective collimator A703 is fixedly connected to the back of the polarizing plate A702. The reflective collimator A703 is arranged to facilitate the introduction of laser light.

[0034] A collimator body 11 is fixedly connected to the interior of the pinhole 501, a filter 12 is fixedly connected to one side of the collimator body 11, and a collecting lens body 13 is fixedly connected to one side of the filter 12. The setting of the collecting lens body 13 plays a role in collecting light of a specific wavelength;

[0035] A plurality of threaded holes are provided on the surface of the base 1 , and threaded posts 14 are connected to the inner threads of the threaded holes. The threaded posts 14 are arranged to fix the optical instrument.

[0036] The model of the back-to-back biconical lens group 701 is: AX2520-A; the model of the polarizer A702 and the polarizer B9 is: FLP20-VIS; the model of the dichroic mirror 6 is: FF414-Di01-25×36; the model of the reflector A302, the reflector B403, the reflector C404 and the reflector D8 is: RAP125-A; the model of the galvanometer 304 is: S-8107C; the model of the scanning lens 303 is: VSL-FL-60; the model of the lock-in amplifier 503 is: DCS500PA; the above parameters and models can be selected according to actual conditions

[0037] In the utility model, the working steps of the device are as follows:

[0038] The first step: when in use, the double light beams are first collimated by a reflective collimator to become approximately parallel light, and then pass through a polarizer after collimation. The polarizer is adjusted to make the double light beams P light, and then the detection light beam passes through a back-to-back biconical lens group 701 to complete beam shaping, forming an annular high-frequency illumination light. The shaped annular detection light is transmitted through the dichroic mirror 6, and the pump light first passes through the reflector D8, and the incident light is reflected by the dichroic mirror 6; the double light beams realize beam coaxiality after passing through the dichroic mirror 6, and then pass through the spatial light isolation mechanism 4 together to make it become right-handed circularly polarized light, and then enter the objective lens 2 through the galvanometer 304, the scanning lens 303 and the tube lens 301;

[0039] The second step: when in use, the reflected signal and diffracted photothermal signal of the detection light and pump light pass through the objective lens 2, tube lens 301, reflector A302, scanning lens 303, and galvanometer 304 in reverse, and then pass through the quarter glass 401 to become vertical linear polarized light, and then pass through the polarization splitter prism to become reflected and emitted, and then pass through the reflector B403 to enter the aperture and collecting lens module 406, and then the diffraction and scattering signals of the detection light beam and the scattering signals of the pump light are converged by the aperture and collecting lens module 406 and collected by the pinhole 501. At this time, the collected signal also has the reflected light of the pump light, so it is connected to the detection module via an optical fiber, connected to the collimator body 11 and emitted in parallel, and enters the filter 12, whose function is to filter out the pump light, and then converges through the collecting lens body 13 to enter the pinhole 501, and the photomultiplier tube converts the optical signal into an electrical signal, and then inputs it into the phase-locked amplifier 503, which can demodulate the thermal wave signal according to the frequency of the photothermal signal and output a DC voltage signal.

[0040] It should be noted that the equipment structure and drawings of the utility model mainly describe the principle of the utility model. In terms of the technology of the design principle, the settings of the power mechanism, power supply system and control system of the device are not fully described. On the premise that the technical personnel in this field understand the principle of the above utility model, the details of the power mechanism, power supply system and control system can be clearly known. The control method of the application document is automatic control through a controller, and the control circuit of the controller can be realized by simple programming by the technical personnel in this field;

[0041] The standard parts used therein can all be purchased from the market and can be customized according to the instructions and drawings. The specific connection methods of each part adopt conventional means such as mature bolts, rivets, welding, etc. in the prior art. The machinery, parts and equipment all adopt conventional models in the prior art, and the structures and principles of the components known to technical personnel in this field can be known by these technical personnel through technical manuals or through conventional experimental methods.

[0042] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A shielded dark field confocal subsurface nondestructive testing device, comprising a base (1), characterized in that: One side of the surface of the base (1) is conveniently fixedly connected with an objective lens (2), one side of the objective lens (2) is fixedly connected with a scanning mechanism (3), one side of the scanning mechanism (3) is fixedly connected with a spatial light isolation mechanism (4), one side of the spatial light isolation mechanism (4) is fixedly connected with a detection mechanism (5), the other side of the spatial light isolation mechanism (4) is fixedly connected with a dichroic mirror (6), one side of the dichroic mirror (6) is fixedly connected with a ring light shaping mechanism (7), the other side of the dichroic mirror (6) is fixedly connected with a reflector D (8), the back of the reflector D (8) is fixedly connected with a polarizing plate B (9), and the back of the polarizing plate B (9) is fixedly connected with a reflective collimator B (10).

2. The shielded dark field confocal subsurface nondestructive testing equipment according to claim 1, characterized in that: The scanning mechanism (3) comprises a tube lens (301) fixedly connected to one side of the objective lens (2); a reflector A (302) is fixedly connected to one side of the tube lens (301); a scanning lens (303) is fixedly connected to the front of the reflector A (302); and a galvanometer (304) is fixedly connected to the front of the scanning lens (303).

3. The shielded dark field confocal subsurface nondestructive testing equipment according to claim 1, characterized in that: The spatial light isolation mechanism (4) comprises a quarter glass slide (401) fixedly connected to one side of the scanning mechanism (3); a PBS (402) is fixedly connected to one side of the quarter glass slide (401); a reflector B (403) is fixedly connected to the front of the PBS (402); a reflector C (404) is fixedly connected to one side of the PBS (402); a diaphragm body (405) is fixedly connected to the back of the reflector C (404); and a diaphragm and a collecting lens module (406) are fixedly connected to one side of the reflector B (403).

4. The shielded dark field confocal subsurface nondestructive testing equipment according to claim 1, characterized in that: The detection mechanism (5) comprises a pinhole (501) fixedly connected to one side of the spatial light isolation mechanism (4), one side of the pinhole (501) is electrically connected to a photodetector (502), and one side of the photodetector (502) is electrically connected to a lock-in amplifier (503) via a power line.

5. The shielded dark field confocal subsurface nondestructive testing equipment according to claim 1, characterized in that: The annular light shaping mechanism (7) comprises a back-to-back biconical lens group (701) fixedly connected to one side of a dichroic mirror (6); a polarizing plate A (702) is fixedly connected to the back of one side of the back-to-back biconical lens group (701); and a reflective collimator A (703) is fixedly connected to the back of the polarizing plate A (702).

6. The shielded dark field confocal subsurface nondestructive testing equipment according to claim 4, characterized in that: A collimator body (11) is fixedly connected inside the pinhole (501), a filter (12) is fixedly connected to one side of the collimator body (11), and a collection lens body (13) is fixedly connected to one side of the filter (12).

7. The shielded dark field confocal subsurface nondestructive testing equipment according to claim 1, characterized in that: A plurality of threaded holes are provided on the surface of the base (1), and threaded columns (14) are connected to the inner threads of the threaded holes.

Images