Detection device and detection method based on bidirectional spatial offset Raman light

Abstract

The invention provides a detection device and a detection method based on bidirectional spatial offset Raman light. The detection device based on bidirectional spatial offset Raman light comprises a laser, an annular light generation device, a first optical fiber bundle and a detector. The laser emits a laser signal, the annular light generating device receives the laser signal and forms annular exciting light on the surface of an object to be detected, the object to be detected generates a Raman light signal, the first optical fiber bundle collects Raman light with the same space offset inside and outside an exciting light ring, and the detector receives the Raman light signal of the first optical fiber bundle and converts the Raman light signal into an electric signal. Spectral information in the to-be-detected object can be obtained by analyzing the electric signal. Therefore, under the condition that the laser signal power is not changed, the laser power density of the surface of the to-be-measured object can be reduced; or the laser power of the surface of the to-be-detected object is improved under the condition that the power density of the laser signal is not changed, so that the strength of the Raman light signal is improved, and the to-be-detected object is detected based on the Raman light with better quality.

Description

Technical Field

[0001] The present invention relates to the field of optical signal detection, and in particular to a detection device and a detection method based on bidirectional spatially offset Raman light. Background Art

[0002] Raman spectroscopy can reflect the vibration information of material molecules and has good chemical specificity. Therefore, it is widely used in the fields of food, medicine and biological testing. However, traditional Raman spectroscopy can only detect information on the surface of the sample, or can only detect through the transparent surface. At present, there is a new type of spatial offset Raman spectroscopy technology (Spatially Offset Raman Spectroscopy, SORS) first proposed by British scientist AW Parker in 2005. Among them, SORS can penetrate the opaque sample surface or outer packaging to obtain the chemical information carried by deeper substances. Therefore, spatial offset Raman spectroscopy technology has a wide range of applications in non-destructive deep detection, such as non-invasive detection of blood components, rapid identification of drug quality, and search for hidden hazardous chemicals. In the above applications, if it is necessary to quickly judge the chemical-specific characteristics of the substance, it is necessary to obtain deep information of the opaque sample.

[0003] The principle of SORS is based on the Raman scattering photon migration theory, such as Figure 1 As shown in the figure, the incident laser can stimulate Raman scattered photons both on the surface and deep inside the sample. The scattered photons in the deep layer are more likely to migrate laterally than those in the surface layer. After multiple scatterings, they finally reach the surface of the sample and are collected by the detector. The Raman scattered photons at different offset distances from the laser incident point as the origin come from different sample depths. Therefore, the signal is collected in the sample surface area farther from the incident point, and the information content from the deep material in the obtained Raman photons is greater. However, there are two common problems in SORS technology: 1. The greater the spatial offset, the weaker the Raman light signal; 2. The single-point excitation method, but in the non-invasive detection scenario of the human body, the skin's tolerance to laser power density is very limited, which limits the laser power of the laser, and the laser power is very important for the Raman light signal. The above two points greatly limit the intensity of the Raman light signal, making the Raman light signal of the deep material very weak and difficult to collect.

[0004] The existing solutions include: adjusting the arrangement of optical elements in the collection optical path to control the spatial offset; or designing a collection optical fiber bundle of multiple optical fibers to maximize the collection efficiency of Raman optical signals. However, due to the limitation of laser power, the far-end Raman optical signals that can be collected by the existing technology are relatively weak. Therefore, how to simultaneously ensure the tolerance of the object to be tested to the laser signal and the collection quality of the Raman optical signal has become one of the problems that technicians in this field need to solve urgently.

[0005] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present invention and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are described in the background technology section of the present invention. Summary of the invention

[0006] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a detection device and a detection method based on bidirectional spatially offset Raman light, so as to solve the problem that the prior art cannot simultaneously guarantee the tolerance of the object to be tested to the laser signal and the collection quality of the Raman light signal.

[0007] To achieve the above-mentioned purpose and other related purposes, the present invention provides a detection device and a detection method based on bidirectional spatially offset Raman light, wherein the detection device based on bidirectional spatially offset Raman light at least comprises: a laser, a ring light generating device, a spatial Raman light collecting device, a first optical fiber bundle and a detector; the laser is used to emit a laser signal; the ring light generating device is connected to the laser, and forms an excitation light in a circular ring shape on the surface of the object to be detected based on the laser signal; the ring light generating device comprises a collimating lens and a conical lens; the collimating lens is used to collimate the laser signal emitted by the laser; The conical lens is located behind the optical path of the collimating lens and is used to generate a circular laser signal; the spatial Raman light collecting device is located on the surface of the object to be measured and is used to collect the Raman light signals inside and outside the excitation light ring; the spatial Raman light collecting device includes a dichroic filter, a first focusing lens and a second focusing lens; the dichroic filter is located behind the optical path of the conical lens and is used to reflect the laser signal and transmit the Raman light signal output by the first focusing lens; the first focusing lens transmits the laser signal reflected by the dichroic filter to the surface of the object to be measured, so that the surface of the object to be measured forms a circular Raman light signal. excitation light; the first focusing lens transmits the Raman light signal generated on the surface of the object to be tested to the dichroic filter; the second focusing lens is located in the Raman light path of the dichroic filter, and transmits the first Raman light signal in the excitation light ring to the inner optical fiber of the first optical fiber bundle at the receiving end, and transmits the second Raman light signal outside the excitation light ring to the outer optical fiber of the first optical fiber bundle at the receiving end; the first optical fiber bundle is used to receive the Raman light signal, and the output end is connected to the detector; the inner optical fiber of the first optical fiber bundle at the receiving end collects the first Raman light signal on the surface of the object to be tested , the outer optical fiber of the first optical fiber bundle at the receiving end collects the second Raman light signal on the surface of the object to be tested; wherein, the first Raman light signal is located in the circular ring of the excitation light, and the inner optical fiber of the first optical fiber bundle at the receiving end includes m optical fibers; the second Raman light signal is located outside the circular ring of the excitation light, and the outer optical fiber of the first optical fiber bundle at the receiving end includes n optical fibers, and m and n are both natural numbers greater than or equal to 1; and the spatial offsets of the first Raman light signal and the second Raman light signal are equal; the detector is used to convert the first Raman light signal and the second Raman light signal into electrical signals.

[0008] Optionally, a first filter is further arranged in the optical path of the collimating lens and the conical lens, and the first filter is used to improve the purity of the laser signal; a second filter is further arranged in the optical path of the dichroic filter and the second focusing lens, and the second filter is used to filter the wavelength of the Raman optical signal.

[0009] To achieve the above-mentioned purpose and other related purposes, the present invention provides a detection device and a detection method based on bidirectional spatially offset Raman light, wherein the detection device based on bidirectional spatially offset Raman light at least comprises: a laser, a ring light generating device, a first optical fiber bundle and a detector; the laser is used to emit a laser signal; the ring light generating device is connected to the laser, and forms an excitation light in a circular ring shape on the surface of the object to be detected based on the laser signal; the ring light generating device comprises a second optical fiber bundle of k optical fibers, wherein k is a natural number greater than or equal to 3; the first end of the second optical fiber bundle is connected to the laser, and the second end emits a laser signal to the surface of the object to be detected; the k optical fibers are arranged in a circular ring shape at the second end of the second optical fiber bundle; the first optical fiber bundle is used to receive the laser signal ... The first optical fiber bundle receives a Raman optical signal, and the output end is connected to the detector; the inner optical fiber of the first optical fiber bundle at the receiving end collects the first Raman optical signal on the surface of the object to be tested, and the outer optical fiber of the first optical fiber bundle at the receiving end collects the second Raman optical signal on the surface of the object to be tested; wherein, the first Raman optical signal is located in the circular ring of the excitation light, and the inner optical fiber of the first optical fiber bundle at the receiving end includes m optical fibers; the second Raman optical signal is located outside the circular ring of the excitation light, and the outer optical fiber of the first optical fiber bundle at the receiving end includes n optical fibers, and m and n are both natural numbers greater than or equal to 1; and the spatial offsets of the first Raman optical signal and the second Raman optical signal are equal; the detector is used to convert the first Raman optical signal and the second Raman optical signal into electrical signals.

[0010] Optionally, when the receiving end of the first optical fiber bundle and the second end of the second optical fiber bundle are both located on the surface of the object to be measured, the inner optical fiber of the first optical fiber bundle at the receiving end is located within the optical fiber ring at the second end of the second optical fiber bundle, and the outer optical fiber of the first optical fiber bundle at the receiving end is located outside the optical fiber ring at the second end of the second optical fiber bundle.

[0011] Optionally, the inner optical fiber 4a of the first optical fiber bundle at the receiving end is located at the center of the excitation light, and m is equal to 1; the outer optical fiber 4b of the first optical fiber bundle at the receiving end is arranged in a ring, and n is greater than or equal to 3.

[0012] Optionally, the inner optical fibers 4a of the first optical fiber bundle at the receiving end are arranged in a ring shape, and m is greater than or equal to 3; the outer optical fibers 4b of the first optical fiber bundle at the receiving end are arranged in a circular ring shape, and n is greater than or equal to 3.

[0013] Optionally, all optical fibers of the first optical fiber bundle are arranged on the same straight line or the same curve at the output end.

[0014] To achieve the above-mentioned purpose and other related purposes, the present invention provides a detection method based on bidirectional spatially offset Raman light, and the detection method based on bidirectional spatially offset Raman light at least includes the following steps: S1: emitting a laser signal to the surface of an object to be tested and forming an annular excitation light; the object to be tested is excited by the annular excitation light, and a Raman light signal is generated on the surface of the object to be tested; collecting a first Raman light signal within the annular excitation light ring on the surface of the object to be tested and a second Raman light signal outside the annular excitation light ring, wherein the spatial offset amounts of the first Raman light signal and the second Raman light signal are equal; and converting the first Raman light signal and the second Raman light signal into electrical signals.

[0015] Optionally, in step S1, the radius of the annular excitation light is adjusted according to a required depth value of the object to be measured; wherein the depth value of the object to be measured is positively correlated with the radius of the annular excitation light.

[0016] Optionally, in step S1, the spatial offset of the first Raman light signal and the second Raman light signal is adjusted according to the required depth value of the object to be measured; wherein the spatial offset of the first Raman light signal and the second Raman light signal is positively correlated with the depth value of the object to be measured.

[0017] As described above, the detection device and detection method based on bidirectional spatially offset Raman light of the present invention have the following beneficial effects:

[0018] 1. The present invention adjusts the shape of the laser signal on the surface of the object to be measured into a circular ring, that is, increases the area of ​​the single-point laser on the surface of the object to be measured. The present invention can reduce the laser power density of the laser signal on the surface of the object to be measured when the total power of the laser signal remains unchanged; the present invention can also increase the total power of the laser signal on the surface of the object to be measured when the power density of the laser signal remains unchanged, so as to improve the collection quality of the Raman optical signal.

[0019] 2. The present invention adjusts the shape of the laser signal on the surface of the object to be tested into a circular ring, so that Raman light can be collected both inside and outside the circular ring. Therefore, the collection of Raman light signals is not interfered by the excitation light on the surface of the object to be tested, thereby improving the collection efficiency of Raman light signals.

[0020] 3. The present invention adjusts the shape of the laser signal on the surface of the object to be measured into a circular ring, which is convenient for setting the first Raman light signal and the second Raman light signal to have the same spatial offset. Therefore, the first optical fiber bundle for collecting Raman light signals of the present invention can directly transmit the light signal to the detector without distinguishing the internal optical fibers, thereby reducing the production cost and difficulty of collecting the first optical fiber bundle. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram showing the relationship between sample depth and spatial offset of Raman light signal in SORS technology.

[0022] Figure 2 It shows a first structural schematic diagram of the detection device based on bidirectional spatially offset Raman light of the present invention.

[0023] Figure 3 The figure shows a top view of the laser signal of the present invention on the surface of the object to be measured.

[0024] Figure 4 It shows a cross-sectional view of the laser signal and the Raman light signal of the present invention on the object to be measured.

[0025] Figure 5 A schematic diagram showing a first structure of the receiving end of the first optical fiber bundle of the present invention

[0026] Figure 6 It is a schematic diagram showing a second structure of the receiving end of the first optical fiber bundle of the present invention.

[0027] Figure 7 A first schematic diagram showing the number of receiving ends of the first optical fiber bundle of the present invention is shown.

[0028] Figure 8 A second schematic diagram showing the number of receiving ends of the first optical fiber bundle of the present invention is shown.

[0029] Fig. 9 A third schematic diagram showing the receiving end of the first optical fiber bundle of the present invention is shown.

[0030] Fig.10 A third structural schematic diagram of the receiving end of the first optical fiber bundle of the present invention is shown.

[0031] Fig.11 A first filling schematic diagram of the receiving end of the first optical fiber bundle of the present invention is shown.

[0032] Fig.12 A second filling schematic diagram of the receiving end of the first optical fiber bundle of the present invention is shown.

[0033] Fig.13 A first schematic diagram showing the output end of the first optical fiber bundle of the present invention is shown.

[0034] Fig.14 A second schematic diagram showing the output end of the first optical fiber bundle of the present invention is shown.

[0035] Fig.15 A second schematic diagram showing the output end of the first optical fiber bundle of the present invention is shown.

[0036] Fig.16 It shows a second structural schematic diagram of the detection device based on bidirectional spatially offset Raman light of the present invention.

[0037] Fig.17 It is a first schematic diagram of the polymerization of the first optical fiber bundle receiving end and the second end of the second optical fiber bundle of the present invention.

[0038] Fig.18 It is a second schematic diagram showing the polymerization of the first optical fiber bundle receiving end and the second end of the second optical fiber bundle according to the present invention.

[0039] Component number description

[0040] 1 Laser

[0041] 2 Ring light generator

[0042] 2a Collimating lens

[0043] 2b Conical lens

[0044] 2c First filter

[0045] 3 Spatial Raman light collection device

[0046] 3a Dichroic Filters

[0047] 3b First focusing lens

[0048] 3c Second focusing lens

[0049] 3d second filter

[0050] 4. First fiber bundle

[0051] 4a The inner fiber of the first fiber bundle at the receiving end

[0052] 4b The outer fiber of the second fiber bundle at the receiving end

[0053] 4c Opaque filling material

[0054] 4d cylindrical structure

[0055] 5 Detector DETAILED DESCRIPTION

[0056] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0057] See also Figure 1-Figure 18It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0058] like Figure 1 As shown, there is a SORS technology that collects Raman light signals by single-point excitation and outer circle collection. The larger the spatial offset, the weaker the Raman light signal. The intensity of the Raman light signal can be increased by increasing the power of the single-point laser signal. However, due to the small area of ​​the single-point laser, the laser power density received by the object to be tested will also be greatly increased, and the risk of burning on the surface of the object to be tested will increase. Therefore, it is impossible to increase the intensity of the Raman light signal by increasing the power of the single-point laser. Simply increasing the area of ​​the single-point laser on the surface of the object to be tested will result in the inability to collect the Raman light signal covered by the laser signal. The present invention increases the area of ​​the laser signal without affecting the collection of the Raman light signal by designing the laser signal on the surface of the object to be tested as a ring light. Therefore, the present invention can increase the power of the laser signal when the laser power density on the surface of the object to be tested remains unchanged, or reduce the laser power density on the surface of the object to be tested when the laser signal power remains unchanged. The specific implementation plan is as follows:

[0059] Embodiment 1

[0060] like Figure 2 As shown, this embodiment provides a detection device based on bidirectional spatially offset Raman light, and the detection device based on bidirectional spatially offset Raman light includes: a laser 1, a ring light generating device 2, a spatial Raman light collecting device 3, a first optical fiber bundle 4 and a detector 5.

[0061] like Figure 2 As shown, the laser 1 is used to emit laser signals.

[0062] like Figure 2 As shown, the ring light generating device 2 is connected to the laser 1, and forms an excitation light in a circular ring shape on the surface of the object to be measured based on the laser signal; the ring light generating device 2 includes a collimating lens 2a and a conical lens 2b; the collimating lens 2a is used to collimate the laser signal emitted by the laser; the conical lens 2b is located behind the optical path of the collimating lens 2a, and is used to generate a circular ring laser signal.

[0063] Specifically, in this embodiment, Figure 3As shown, the laser signal passes through the ring light generating device to form a circular ring-shaped excitation light on the surface of the object to be tested. The projection area of ​​the excitation light on the surface of the object to be tested is increased compared to the single-point excitation light. When the total power of the ring excitation light is consistent with that of the single-point excitation light, the power density of the ring excitation light is reduced, thereby reducing the risk of burning the object to be tested; when the power density of the ring excitation light is consistent with that of the single-point excitation light, the total power of the ring excitation light is increased, thereby improving the collection quality of the Raman light signal (signal intensity and collection efficiency). Furthermore, when the excitation light signal is distributed in a circular ring shape on the surface of the object to be tested, such as Figure 4 As shown, Raman light signals can be collected both inside and outside the excitation light ring, so the collection of Raman light signals is not blocked by the shape of the excitation light signal. Furthermore, setting the excitation light signal on the surface of the object to be tested in a ring shape can also adapt to the shape of common optical fiber bundles, facilitate the first optical fiber bundle 4 to collect Raman light signals, and facilitate the industrial production of detection devices based on bidirectional spatial offset Raman light.

[0064] Specifically, in this embodiment, the purpose of using the collimating lens 2a is to shape the laser signal to facilitate subsequent processing of the laser signal; the conical lens 2b can make the laser signal into a ring shape. In practical applications, any lens that can make the laser signal produce a circular shape can replace the conical lens 2b, which is not limited to this embodiment.

[0065] Specifically, in this embodiment, a first filter 2c is further provided in the optical path of the collimating lens 2a and the conical lens 2b. The first filter 2c is used to improve the purity of the laser signal in order to improve the utilization efficiency of the laser signal.

[0066] like Figure 2 As shown, the spatial Raman light collecting device 3 is located on the surface of the object to be measured, and is used to collect Raman light signals inside and outside the excitation light ring; the spatial Raman light collecting device 3 includes a dichroic filter 3a, a first focusing lens 3b and a second focusing lens 3c; the dichroic filter 3a is located behind the optical path of the conical lens 2b, and is used to reflect the laser signal and transmit the Raman light signal output by the first focusing lens 3b; the first focusing lens 3b transmits the laser signal reflected by the dichroic filter 3a to the surface of the object to be measured, so that a ring-shaped excitation light is formed on the surface of the object to be measured; the first focusing lens 3b also transmits the Raman light signal generated on the surface of the object to be measured to the dichroic filter 3a; the second focusing lens 3c is located on the Raman light path of the dichroic filter 3a, and transmits the first Raman light signal in the excitation light ring to the inner optical fiber 3a of the first optical fiber bundle at the receiving end, and transmits the second Raman light signal outside the excitation light ring to the outer optical fiber 3b of the first optical fiber bundle at the receiving end.

[0067] Specifically, in the present embodiment, the dichroic filter 3a and the first focusing lens 3b are not only located in the optical path of the laser signal, but also in the optical path of the Raman optical signal; the dichroic filter 3a changes the optical path direction of the laser signal, and the first focusing lens 3b increases the power of the laser signal; after the excitation light signal is formed on the surface of the object to be measured, a Raman optical signal is generated, and the first focusing lens 3b transmits the Raman optical signal to the dichroic filter 3a, and the dichroic filter 3a filters the wavelength of the Raman optical signal.

[0068] Specifically, in this embodiment, a second filter 3d is further provided in the optical path of the dichroic filter 3a and the second focusing lens 3c. The second filter 3d is used to filter the wavelength of the Raman optical signal in order to extract the Raman optical signal of the required wavelength.

[0069] Specifically, in the present embodiment, the first Raman light signal on the inner side of the annular excitation light on the surface of the object to be measured is projected onto the inner optical fiber 4a of the first optical fiber bundle at the receiving end based on M times the spatial offset, and the second Raman light signal on the outer side of the annular excitation light on the surface of the object to be measured is projected onto the outer optical fiber 4b of the first optical fiber bundle at the receiving end based on M times the spatial offset; wherein M represents the imaging magnification, that is, M=f2 / f1, f2 represents the focal length f2 of the second focusing lens 2e, and f1 represents the focal length f1 of the first focusing lens 2d.

[0070] like Figure 2 As shown, the first optical fiber bundle 4 is used to receive Raman light signals, and the output end is connected to the detector; the inner optical fiber 4a of the first optical fiber bundle at the receiving end collects the first Raman light signal generated on the surface of the object to be measured, and the outer optical fiber 4b of the first optical fiber bundle at the receiving end collects the second Raman light signal generated on the surface of the object to be measured; wherein, the first Raman light signal is located in the circular ring of the excitation light, and the inner optical fiber of the first optical fiber bundle at the receiving end includes m optical fibers; the second Raman light signal is located outside the circular ring of the excitation light, and the outer optical fiber of the first optical fiber bundle at the receiving end includes n optical fibers, and m and n are both natural numbers greater than or equal to 1; and the spatial offset of the first Raman light signal and the second Raman light signal is equal.

[0071] Specifically, in this embodiment, the object to be tested is excited by the excitation light signal, and a Raman scattering effect is generated inside the object to be tested. The excited point of the Raman light on the object to be tested is taken as the reference origin, and the distance from the Raman light in the lateral migration direction of the surface of the object to be tested to the reference origin is the spatial offset. Furthermore, the spatial offset of the first Raman light signal is equal to that of the second Raman light signal, so that the first Raman light signal and the second Raman light signal both correspond to the information of the same depth to be tested. Therefore, the first optical fiber bundle 3 does not need to distinguish the collected Raman light signals, and the first optical fiber bundle 4 does not need to perform interval processing on each optical fiber, thereby reducing the production cost and production difficulty of the first optical fiber bundle 4. Furthermore, the optical fiber for collecting the first Raman light signal and the optical fiber for collecting the second Raman light signal in the first optical fiber bundle are both light-transmitting optical fibers.

[0072] Specifically, in this embodiment, the first Raman light signal can be collected by any m optical fibers with equal spatial offsets within the excitation light ring. For example, Figure 5 As shown, part of the optical fibers on the concentric rings within the excitation light ring can be selected as the inner optical fibers 4a of the first optical fiber bundle at the receiving end, and m is equal to 6 at this time. Alternatively, all the optical fibers on the concentric rings within the excitation light ring can be selected as the inner optical fibers 4a of the first optical fiber bundle at the receiving end, and m is equal to 12 at this time. Furthermore, the second Raman optical signal can be collected by any n optical fibers with equal spatial offsets outside the excitation light ring. As an example, Figure 5 As shown, part of the optical fibers on the concentric rings outside the excitation light ring can be selected as the outer optical fibers 4b of the first optical fiber bundle at the receiving end, and n is equal to 18 at this time. Alternatively, all the optical fibers on the concentric rings outside the excitation light ring can be selected as the outer optical fibers of the first optical fiber bundle at the receiving end, and n is equal to 36 at this time. In practical applications, the specific values ​​of m and n are set as needed, and are not limited to this embodiment.

[0073] Specifically, in this embodiment, Figure 6 As shown, the inner optical fiber 4a of the first optical fiber bundle at the receiving end is located at the center of the excitation light to collect the first Raman light signal, and m is equal to 1; the outer optical fiber 4b of the first optical fiber bundle at the receiving end is arranged in a circular ring to collect the second Raman light signal, and n is greater than or equal to 3, as shown in FIG. Figure 6 The first optical fiber bundle 4 shown is easier to set and measure because it uses the radius as the spatial offset, so it can greatly ensure that the collected Raman optical signals are all of the same spatial offset. Furthermore, when the radius of the excitation optical signal changes, the radius of the outer optical fiber 4b of the first optical fiber bundle at the receiving end should also be changed accordingly. For example, Figure 7 As shown, when the radius of the excitation light signal is large, the outer optical fiber 4b of the first optical fiber bundle at the receiving end includes 36 optical fibers, and the radius of the outer optical fiber 4b of the first optical fiber bundle at the receiving end is also large; Figure 8As shown, when the radius of the excitation light signal is moderate, the outer optical fiber 4b of the first optical fiber bundle at the receiving end includes 24 optical fibers, and at this time the radius of the outer optical fiber 4b of the first optical fiber bundle at the receiving end is also moderate; Fig. 9 As shown, when the radius of the excitation light signal is small, the outer optical fiber 4b of the first optical fiber bundle at the receiving end includes 12 optical fibers, and the radius of the outer optical fiber 4b of the first optical fiber bundle at the receiving end is also small. In actual applications, the number of optical fibers of the outer optical fiber 4b of the first optical fiber bundle at the receiving end is adjusted as needed, and is not limited to this embodiment.

[0074] Specifically, in this embodiment, Fig.10 As shown, the inner optical fiber 4a of the first optical fiber bundle at the receiving end is arranged in a circular ring to collect the first Raman optical signal, and m is greater than or equal to 3; the outer optical fiber 4b of the first optical fiber bundle at the receiving end is arranged in a circular ring to collect the second Raman optical signal, and n is greater than or equal to 3, as shown in FIG. Fig.10 The first optical fiber bundle 4 shown can be more flexibly set with a spatial offset according to the size of the first optical fiber bundle 3. Furthermore, the specific number of optical fibers of the inner optical fiber 4a and the outer optical fiber 4b of the corresponding first optical fiber bundle at the receiving end is set according to the spatial offset required by the depth of the object to be measured, which is not limited to this embodiment.

[0075] Specifically, in this embodiment, Fig.11 and Fig.12 As shown, the first optical fiber bundle is filled with an opaque filling material 4c between the inner optical fiber 4a and the outer optical fiber 4b at the receiving end, in order to fix the relative position of the first optical fiber bundle between the inner optical fiber 4a and the outer optical fiber 4b at the receiving end. As an example, Fig.11 As shown, the opaque filling material 4c can be an opaque optical fiber, such as Fig.12 As shown, the opaque filling material 4c can also be plastic or quartz. In practical applications, the material of the opaque filling material 4c is set as needed, and is not limited to this embodiment. Further, the first optical fiber bundle 4 can also include a cylindrical structure 4d, and the receiving end of the first optical fiber bundle 4 is set in the cylindrical structure 4d, in order to fix the specific positions of the inner optical fiber 4a and the outer optical fiber 4b of the first optical fiber bundle at the receiving end.

[0076] Specifically, in this embodiment, Fig.13 , Fig.14 , Fig.15 As shown, the end of the first optical fiber bundle close to the object to be measured is the receiving end, and the end of the first optical fiber bundle connected to the detector is the output end. Fig.13 (and Figure 7 corresponding to the receiving end of the first optical fiber bundle), Fig.14 (and Figure 8 corresponding to the receiving end of the first optical fiber bundle), Fig.15 (and Fig. 9 As shown in FIG. 1 , the inner optical fiber 4a and the outer optical fiber 4b of the first optical fiber bundle at the receiving end are converted to the output end and arranged on the same straight line or the same curve. The purpose of arranging them in the same straight line or the same curve is to make the first optical fiber bundle 4 adapt to the shape of the light entrance slit of the detector 5 so that all the Raman light signals in the first optical fiber bundle 4 enter the detector. In practical applications, the inner optical fiber 4a and the outer optical fiber 4b of the first optical fiber bundle at the receiving end can be converted to the output end and arranged at any position in the straight line / curve, and are not limited to the arrangement position of the inner optical fiber 4a of the first optical fiber bundle in the present embodiment being located in the middle of the straight line / curve and the outer optical fiber 4b being located on both sides of the inner optical fiber 4a.

[0077] like Figure 2 As shown, the detector 5 is used to convert the first Raman optical signal and the second Raman optical signal into electrical signals.

[0078] Specifically, in this embodiment, since the spatial offsets of the first Raman optical signal and the second Raman optical signal are equal, the detector 5 may not distinguish between the first Raman optical signal and the second Raman optical signal, and display the electrical signal converted from the Raman optical signal to observe the intensity, frequency, wavelength and other information of the Raman optical signal. Ultimately, this embodiment can obtain specific information inside the object to be tested.

[0079] Embodiment 2

[0080] like Fig.16 As shown, this embodiment provides a detection device based on bidirectional spatially offset Raman light. The difference between this embodiment and embodiment 1 is that: this embodiment does not include a spatial Raman light collecting device 3, and the annular light generating device 2 of this embodiment includes a second optical fiber bundle of k optical fibers, wherein k is a natural number greater than or equal to 3; the first end of the second optical fiber bundle is connected to the laser 1, and the second end emits a laser signal to the surface of the object to be detected; the k optical fibers are arranged in a circular ring at the second end of the second optical fiber bundle.

[0081] Specifically, in this embodiment, Fig.16 As shown, when the receiving end of the first optical fiber bundle 4 and the second end of the second optical fiber bundle 2 are both located on the surface of the object to be tested, that is, the second optical fiber bundle 2 directly transmits the laser signal to the surface of the object to be tested, and the first optical fiber bundle 4 directly collects the Raman light signal on the surface of the object to be tested, the inner optical fiber 4a of the first optical fiber bundle at the receiving end is located in the ring of the optical fiber at the second end of the second optical fiber bundle 2, and the outer optical fiber 4b of the first optical fiber bundle at the receiving end is located outside the optical fiber ring at the second end of the second optical fiber bundle 2. The purpose is to facilitate the emission of laser signals to the surface of the object to be tested and the collection of Raman light signals, that is, the first optical fiber bundle 4 and the second optical fiber bundle form a polymerized optical fiber bundle on the surface of the object to be tested, which is conducive to the industrial production of detection devices based on bidirectional spatial offset Raman light. As an example, Fig.17As shown, the inner optical fiber 4a of the first optical fiber bundle at the receiving end is located at the center of the excitation light, the second end of the second optical fiber bundle 2 generates excitation light on the surface of the object to be measured, and the outer optical fiber 4b of the first optical fiber bundle at the receiving end is located outside the excitation light and is distributed in a ring shape; Fig.18 As shown, the inner optical fiber 4a of the first optical fiber bundle at the receiving end is located on the inner side of the excitation light and is distributed in a ring shape, the second end of the second optical fiber bundle 2 generates excitation light on the surface of the object to be measured, and the outer optical fiber 4b of the first optical fiber bundle at the receiving end is located on the outer side of the excitation light and is distributed in a ring shape.

[0082] Embodiment 3

[0083] This embodiment provides a detection method based on bidirectional spatially offset Raman light. The detection method based on bidirectional spatially offset Raman light includes the following steps:

[0084] like Figure 2 and Fig.16 As shown, in step S1, a laser signal is emitted to the surface of the object to be tested and an annular excitation light is formed; the object to be tested is excited by the annular excitation light, and a Raman light signal is generated on the surface of the object to be tested; a first Raman light signal within the annular excitation light ring and a second Raman light signal outside the annular excitation light ring on the surface of the object to be tested are collected, and the spatial offsets of the first Raman light signal and the second Raman light signal are equal; and the first Raman light signal and the second Raman light signal are converted into electrical signals.

[0085] Specifically, in this embodiment, in order to increase the projection area of ​​the excitation light on the surface of the object to be measured, this embodiment makes the shape of the excitation light signal on the surface of the object to be measured a circular ring. When the excitation light power remains unchanged, the power density of the ring-shaped excitation light is reduced. When the power density of the ring-shaped excitation light remains unchanged, the total power of the ring-shaped excitation light is increased. Furthermore, the ring-shaped excitation light does not affect the collection of Raman light signals of various spatial offsets, and the ring-shaped excitation light can also adapt to the shape of common optical fiber bundles.

[0086] Specifically, in this embodiment, when the radius of the annular excitation light signal changes, the spatial offset at a fixed position on the surface of the object to be measured will also change. Therefore, by adjusting the radius of the annular excitation light, information at different depths at a fixed position on the surface of the object to be measured can be obtained. When the required depth value of the object to be measured increases, the radius of the annular excitation light signal is increased, and when the required depth value of the object to be measured decreases, the radius of the annular excitation light signal is reduced.

[0087] Specifically, in this embodiment, according to the depth value of the object to be detected, the spatial offset of the first Raman light signal and the spatial offset of the second Raman light signal can also be adjusted to obtain the Raman light signals scattered from different positions on the surface of the object to be detected. When the required depth value of the object to be detected increases, the spatial offset of the first Raman light signal and the second Raman light signal is increased, and when the required depth value of the object to be detected decreases, the spatial offset of the first Raman light signal and the second Raman light signal is reduced.

[0088] Specifically, in the present embodiment, the purpose of setting the first Raman optical signal and the second Raman optical signal to have the same spatial offset is that the Raman optical signals with the same spatial offset have the same depth information of the object to be detected, and in the subsequent electrical signal processing, it is convenient to uniformly process the first Raman optical signal and the second Raman optical signal; through the electrical processing of the Raman optical signal, the embodiment can better detect the object to be detected.

[0089] In this embodiment, this embodiment can be implemented based on the devices of implementation examples 1 to 2. In actual applications, the device for implementing this embodiment is selected as needed and is not limited to this embodiment.

[0090] In summary, the detection device and detection method based on bidirectional spatial offset Raman light of the present invention include a laser, a ring light generating device, a first optical fiber bundle and a detector, the laser emits a laser signal, the ring light generating device receives the laser signal and forms a ring excitation light on the surface of the object to be tested, the object to be tested generates a Raman light signal, the first optical fiber bundle collects Raman light with the same spatial offset inside and outside the excitation light ring, the detector receives the Raman light signal of the first optical fiber bundle and converts it into an electrical signal, and the information inside the object to be tested can be obtained by analyzing the electrical signal. Therefore, the present invention can reduce the laser power density on the surface of the object to be tested when the power of the excitation light signal remains unchanged, so as to improve the tolerance of the surface of the object to be tested; when the power density of the excitation light signal remains unchanged, the power of the laser signal is increased, and the intensity of the Raman light signal can be increased. Based on the Raman light with better intensity, the present invention can perform better quality detection of the object to be tested. In addition, the present invention has the advantages of high industrialization, simple structure and convenience. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0091] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A detection device based on bidirectional spatially offset Raman light, characterized in that: The detection device based on bidirectional spatial offset Raman light at least comprises: a laser, a ring light generating device, a spatial Raman light collecting device, a first optical fiber bundle and a detector; The laser is used to emit a laser signal; The annular light generating device is connected to the laser, and forms an excitation light in the shape of an annular ring on the surface of the object to be measured based on the laser signal; the annular light generating device includes a collimating lens and a conical lens; the collimating lens is used to collimate the laser signal emitted by the laser; the conical lens is located after the optical path of the collimating lens, and is used to generate an annular laser signal; The spatial Raman light collecting device is located on the surface of the object to be measured, and is used to collect Raman light signals inside and outside the excitation light ring; the spatial Raman light collecting device includes a dichroic filter, a first focusing lens and a second focusing lens; the dichroic filter is located behind the optical path of the conical lens, and is used to reflect the laser signal and transmit the Raman light signal output by the first focusing lens; the first focusing lens transmits the laser signal reflected by the dichroic filter to the surface of the object to be measured, so that a ring-shaped excitation light is formed on the surface of the object to be measured; the first focusing lens also transmits the Raman light signal generated on the surface of the object to be measured to the dichroic filter; the second focusing lens is located on the Raman light path of the dichroic filter, and transmits the first Raman light signal within the excitation light ring to the inner optical fiber of the first optical fiber bundle at the receiving end, and transmits the second Raman light signal outside the excitation light ring to the outer optical fiber of the first optical fiber bundle at the receiving end; The first optical fiber bundle is used to receive Raman light signals, and the output end is connected to the detector; the inner optical fiber of the first optical fiber bundle at the receiving end collects the first Raman light signal on the surface of the object to be measured, and the outer optical fiber of the first optical fiber bundle at the receiving end collects the second Raman light signal on the surface of the object to be measured; wherein, the first Raman light signal is located in the circular ring of the excitation light, and the inner optical fiber of the first optical fiber bundle at the receiving end includes m optical fibers; the second Raman light signal is located outside the circular ring of the excitation light, and the outer optical fiber of the first optical fiber bundle at the receiving end includes n optical fibers, and m and n are both natural numbers greater than or equal to 1; and the spatial offsets of the first Raman light signal and the second Raman light signal are equal; The detector is used to convert the first Raman optical signal and the second Raman optical signal into electrical signals.

2. The detection device based on bidirectional spatially offset Raman light according to claim 1, characterized in that: A first filter is also arranged in the optical path of the collimating lens and the conical lens, and the first filter is used to improve the purity of the laser signal; a second filter is also arranged in the optical path of the dichroic filter and the second focusing lens, and the second filter is used to filter the wavelength of the Raman optical signal.

3. A detection device based on bidirectional spatially offset Raman light, characterized in that: The detection device based on bidirectional spatially offset Raman light at least comprises: a laser, a ring light generating device, a first optical fiber bundle and a detector; The laser is used to emit a laser signal; The annular light generating device is connected to the laser, and forms an excitation light in a circular ring shape on the surface of the object to be measured based on the laser signal; the annular light generating device comprises a second optical fiber bundle of k optical fibers, wherein k is a natural number greater than or equal to 3; a first end of the second optical fiber bundle is connected to the laser, and a second end thereof emits a laser signal to the surface of the object to be measured; k optical fibers are arranged in a ring shape at the second end of the second optical fiber bundle; The first optical fiber bundle is used to receive Raman light signals, and the output end is connected to the detector; the inner optical fiber of the first optical fiber bundle at the receiving end collects the first Raman light signal on the surface of the object to be measured, and the outer optical fiber of the first optical fiber bundle at the receiving end collects the second Raman light signal on the surface of the object to be measured; wherein, the first Raman light signal is located in the circular ring of the excitation light, and the inner optical fiber of the first optical fiber bundle at the receiving end includes m optical fibers; the second Raman light signal is located outside the circular ring of the excitation light, and the outer optical fiber of the first optical fiber bundle at the receiving end includes n optical fibers, and m and n are both natural numbers greater than or equal to 1; and the spatial offsets of the first Raman light signal and the second Raman light signal are equal; The detector is used to convert the first Raman optical signal and the second Raman optical signal into electrical signals.

4. The detection device based on bidirectional spatially offset Raman light according to claim 3, characterized in that: When the receiving end of the first optical fiber bundle and the second end of the second optical fiber bundle are both located on the surface of the object to be measured, the inner optical fiber of the first optical fiber bundle at the receiving end is located within the optical fiber ring at the second end of the second optical fiber bundle, and the outer optical fiber of the first optical fiber bundle at the receiving end is located outside the optical fiber ring at the second end of the second optical fiber bundle.

5. The detection device based on bidirectional spatially offset Raman light according to any one of claims 1 to 4, characterized in that: The inner optical fiber 4a of the first optical fiber bundle at the receiving end is located at the center of the excitation light, and m is equal to 1; the outer optical fiber 4b of the first optical fiber bundle at the receiving end is arranged in a ring shape, and n is greater than or equal to 3.

6. The detection device based on bidirectional spatially offset Raman light according to any one of claims 1 to 4, characterized in that: The inner optical fibers 4a of the first optical fiber bundle at the receiving end are arranged in a ring shape, and m is greater than or equal to 3; the outer optical fibers 4b of the first optical fiber bundle at the receiving end are arranged in a circular ring shape, and n is greater than or equal to 3.

7. The detection device based on bidirectional spatially offset Raman light according to any one of claims 1 to 4, characterized in that: All optical fibers of the first optical fiber bundle are arranged on the same straight line or the same curve at the output end.

8. A detection method based on bidirectional spatially offset Raman light, characterized in that: The detection method based on bidirectional spatially offset Raman light comprises at least the following steps: S1: emit a laser signal to the surface of the object to be tested and form an annular excitation light; the object to be tested is excited by the annular excitation light, and a Raman light signal is generated on the surface of the object to be tested; collect a first Raman light signal within the annular excitation light ring on the surface of the object to be tested and a second Raman light signal outside the annular excitation light ring, wherein the spatial offsets of the first Raman light signal and the second Raman light signal are equal; convert the first Raman light signal and the second Raman light signal into electrical signals.

9. The detection method based on bidirectional spatially offset Raman light according to claim 8, characterized in that: In step S1, the radius of the annular excitation light is adjusted according to the required depth value of the object to be measured; wherein the depth value of the object to be measured is positively correlated with the radius of the annular excitation light.

10. The detection method based on bidirectional spatially offset Raman light according to claim 8, characterized in that: In step S1, the spatial offset of the first Raman light signal and the second Raman light signal is adjusted according to the required depth value of the object to be measured; wherein the spatial offset of the first Raman light signal and the second Raman light signal is positively correlated with the depth value of the object to be measured.

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