Optical path system for reducing baseline tilt in near infrared spectroscopy

Abstract

The present application relates to a kind of near infrared spectrometer, especially to a kind of optical path system for reducing the baseline tilt of near infrared spectrum, comprising: first optical fiber, second optical fiber, first off-axis parabolic mirror, second off-axis parabolic mirror, multiple mirrors and body;First off-axis parabolic mirror is used to reflect the light fiber emitted by first optical fiber to mirror, and the light fiber is reflected to second off-axis parabolic mirror again through mirror, and finally reflected to second optical fiber by second off-axis parabolic mirror and gathered.The both ends of body are provided with first sliding groove and second sliding groove, for the sliding of first off-axis parabolic mirror and second off-axis parabolic mirror to adjust optical path, and multiple mirrors are further provided between body, so that first optical fiber and second optical fiber are communicated.By the structure of the present application, the optical path can be conveniently adjusted by movable sliding groove, and the position of optical fiber is more easily organized by the intervention of mirror.

Description

Technical Field

[0001] This invention relates to a near-infrared spectrometer, and more particularly to an optical path system for reducing near-infrared spectral baseline tilt. Background Technology

[0002] The description in this section provides only background information related to the disclosure of this invention and does not constitute prior art.

[0003] Current near-infrared equipment generally uses a transmission optical path. In addition, during the use of near-infrared spectrometers, it is usually necessary to plug and unplug the optical fiber multiple times or to perform offline modeling on the host. Therefore, the original optical path state may be changed. Furthermore, lens dispersion at tolerance-sensitive positions near the optical path plugging and unplugging position can cause baseline tilting, which affects the measurement of near-infrared spectrum.

[0004] Therefore, some existing near-infrared spectrometers consider using off-axis reflective optical paths to eliminate the effects of dispersion. However, due to the large size of the on-axis parabolic mirror and the complexity of optical path adjustment and the higher precision requirements, it is not convenient to make rapid adjustments, which seriously affects the measurement efficiency. Alternatively, an unreasonable layout of the optical path may limit the insertion angle of the optical fiber, which also affects the convenience of measurement.

[0005] Currently, there is no optical path system that can solve the above problem by reducing the near-infrared spectral baseline tilt. Summary of the Invention

[0006] The purpose of this invention is to provide an optical path system that reduces the near-infrared spectral baseline tilt, which allows for convenient adjustment of the optical path via a movable slide, and facilitates the arrangement of the optical fiber by incorporating a reflector.

[0007] To achieve the above objectives, the present invention discloses an optical path system for reducing near-infrared spectral baseline tilt; the optical path system for reducing near-infrared spectral baseline tilt includes:

[0008] The system comprises a first optical fiber, a second optical fiber, a first off-axis parabolic mirror, a second off-axis parabolic mirror, multiple mirrors, and a main body.

[0009] The free end of the first optical fiber is aligned with the focal point of the first off-axis parabolic mirror. A first connecting line is formed between the first single-core optical fiber and the focal point of the first off-axis parabolic mirror. A second connecting line is formed between the focal point of the first off-axis parabolic mirror and one of the corresponding reflectors. The included angle between the first connecting line and the second connecting line is the same as the off-axis angle of the first off-axis parabolic mirror.

[0010] The free end of the second optical fiber is aligned with the focal point of the second off-axis parabolic mirror. A third connecting line is formed between the second single-core optical fiber and the focal point of the second off-axis parabolic mirror. A fourth connecting line is formed between the focal point of the second off-axis parabolic mirror and one of the corresponding reflectors. The angle formed between the second connecting line and the fourth connecting line is the same as the off-axis angle of the second off-axis parabolic mirror.

[0011] The main body has a first groove and a second groove at both ends. The first off-axis parabolic mirror is installed in the first groove and can move back and forth in the first groove. The second off-axis parabolic mirror is installed in the second groove and can move back and forth in the second groove. By moving the first off-axis parabolic mirror and the second off-axis parabolic mirror, the light beam emitted from the free end of the first optical fiber and passing through the first connecting line is reflected by the first off-axis parabolic mirror, the second off-axis parabolic mirror and the plurality of mirrors, and then passes through the third connecting line and is focused by the free end of the second optical fiber.

[0012] Furthermore, there are two reflectors, and the two reflectors are arranged parallel to each other, so that the first connecting line and the third connecting line are parallel, the second connecting line and the fourth connecting line are parallel, and the second connecting line and the fourth connecting line are connected by a fifth connecting line, which passes through the center of the area to be detected of the body.

[0013] Furthermore, the first off-axis parabolic mirror has a recessed first screw hole on its outer side facing the main body. After the first off-axis parabolic mirror moves to a preset position in the first slide groove, a first baffle with a size larger than the diameter of the first slide groove hole is installed on the outer side of the first slide groove. The first fastener passes through the first baffle and is fixed in the first screw hole, so that the first off-axis parabolic mirror is fixed. The second off-axis parabolic mirror has a recessed second screw hole on its outer side facing the main body. After the second off-axis parabolic mirror moves to a preset position in the second slide groove, a second baffle with a size larger than the diameter of the second slide groove hole is installed on the outer side of the second slide groove. The second fastener passes through the second baffle and is fixed in the second screw hole, so that the second off-axis parabolic mirror is fixed.

[0014] Furthermore, the first off-axis parabolic mirror is fixed in the first groove by adhesive; the second off-axis parabolic mirror is fixed in the second groove by adhesive.

[0015] Furthermore, the first off-axis parabolic mirror and the second off-axis parabolic mirror are configured to be identical.

[0016] Furthermore, the first off-axis parabolic mirror and the second off-axis parabolic mirror are 90-degree off-axis parabolic mirrors.

[0017] Furthermore, the main body includes multiple mounting slots, and multiple reflectors are detachably mounted in the corresponding mounting slots.

[0018] Furthermore, the body includes a first slot and a second slot, the first slot being disposed adjacent to the first off-axis parabolic mirror, and the first optical fiber being detachably inserted into the first slot; the second slot being disposed adjacent to the second off-axis parabolic mirror, and the second optical fiber being detachably inserted into the second slot.

[0019] By employing the above technical solutions, the beneficial effects of the present invention are as follows:

[0020] The optical path system for reducing near-infrared spectral baseline tilt of the present invention can, during installation, set up a corresponding number and angle of reflectors 5 according to the position and angle requirements of the first optical fiber 1 and the second optical fiber 2 in the actual optical path, and install them into the corresponding prefabricated body 6, so that in actual use, the insertion position of the first optical fiber 1 and the second optical fiber 2 into the body 6 is in a state that meets the needs of convenient operation.

[0021] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and illustration only and are not intended to limit the present invention. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a cross-sectional schematic diagram of an optical path system for reducing near-infrared spectral baseline tilt, as provided in the embodiments of this specification.

[0024] Figure 2 This is a three-dimensional schematic diagram of an optical path system for reducing near-infrared spectral baseline tilt, provided in an embodiment of this specification.

[0025] Figure 3 This is a schematic diagram of the lens transmission optical path of an optical path system for reducing near-infrared spectral baseline tilt, provided in the embodiments of this specification.

[0026] Figure 4This is a schematic diagram of an off-axis reflective optical path of an optical path system for reducing near-infrared spectral baseline tilt, provided in the embodiments of this specification.

[0027] Figure 5 This is a schematic diagram of an embodiment of a light path system for detecting fermented mash, which reduces the near-infrared spectral baseline tilt provided in this specification.

[0028] In the figure: 1. First optical fiber; 2. Second optical fiber; 3. First off-axis parabolic mirror; 31. First screw hole; 4. Second off-axis parabolic mirror; 32. Second screw hole; 5. Reflector; 6. Body; 61. First groove; 62. Second groove; 71. First connecting line; 72. Second connecting line; 73. Third connecting line; 74. Fourth connecting line; 75. Fifth connecting line. Detailed Implementation

[0029] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this specification.

[0030] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. Furthermore, the accompanying drawings of the present invention are for simple illustrative purposes only and are not depictions of actual dimensions; this is stated in advance. The following embodiments will further describe the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the scope of protection of the present invention.

[0031] It should be understood that while terms such as "first," "second," and "third" may be used in this document to describe various components or signals, these components or signals should not be limited by these terms. These terms are primarily used to distinguish one component from another, or one signal from another. Furthermore, the term "or" as used herein should, as appropriate, include any combination of one or more of the related listed items.

[0032] Please see Figure 1-2 This embodiment provides an optical path system for reducing near-infrared spectral baseline tilt; the optical path system for reducing near-infrared spectral baseline tilt includes:

[0033] The structure consists of a first optical fiber 1, a second optical fiber 2, a first off-axis parabolic mirror 3, a second off-axis parabolic mirror 4, multiple reflectors 5, and a main body 6.

[0034] The free end of the first optical fiber 1 is aligned with the focal point of the first off-axis parabolic mirror 3. A first connecting line 71 is formed between the first single-core optical fiber 1 and the focal point of the first off-axis parabolic mirror 3. A second connecting line 72 is formed between the focal point of the first off-axis parabolic mirror 3 and one of the corresponding reflectors 5. The included angle between the first connecting line 71 and the second connecting line 72 is the same as the off-axis angle of the first off-axis parabolic mirror 3.

[0035] The free end of the second optical fiber 2 is aligned with the focal point of the second off-axis parabolic mirror 4. A third connecting line 73 is formed between the second single-core optical fiber 2 and the focal point of the second off-axis parabolic mirror 4. A fourth connecting line 74 is formed between the focal point of the second off-axis parabolic mirror 4 and one of the corresponding reflectors 5. The included angle formed between the second connecting line 72 and the fourth connecting line 74 is the same as the off-axis angle of the second off-axis parabolic mirror 4.

[0036] The main body 6 has a first groove 61 and a second groove 62 at both ends. The first off-axis parabolic mirror 3 is installed in the first groove 61 and can move back and forth in the first groove 61. The second off-axis parabolic mirror 4 is installed in the second groove 62 and can move back and forth in the second groove 62. By moving the first off-axis parabolic mirror 61 and the second off-axis parabolic mirror 62, the light beam emitted from the free end of the first optical fiber 1 and passing through the first connecting line 71 is reflected by the first off-axis parabolic mirror 3, the second off-axis parabolic mirror 4 and multiple reflectors 5, and then passes through the third connecting line 73 and is focused by the free end of the second optical fiber 2.

[0037] For the above structure, during installation, according to the position and angle requirements of the first optical fiber 1 and the second optical fiber 2 in the actual optical path, a corresponding number and angle of reflectors 5 can be set and installed into the corresponding prefabricated body 6, so that in actual use, the insertion position of the first optical fiber 1 and the second optical fiber 2 into the body 6 is in a state that meets the needs of convenient operation.

[0038] In the use of this embodiment, if optical path calibration is required, the operator can push the first off-axis parabolic mirror 3, causing it to slide slightly back and forth in the first groove 61 of the body 6, or / simultaneously push the second off-axis parabolic mirror 4, causing it to slide slightly back and forth in the second groove 62 of the body 6, thereby adjusting the overall optical path to meet the requirements. Figure 1As shown, starting from the free end of the first optical fiber 1, the first connecting line 71 can sequentially pass through the second connecting line 72, the fifth connecting line 75, the fourth connecting line 74, and the third connecting line 73 before connecting to the free end of the second off-axis parabolic mirror 4, thus achieving a complete optical path. Then, when the object to be tested is passed into the detection area in the middle of the body 6, the first optical fiber 1 can be activated to emit detection light to detect the object.

[0039] In the above process, when faced with the situation of spectral baseline shift caused by repeated plugging and unplugging, when adjustment is needed, only slight back-and-forth sliding of the first off-axis parabolic mirror 3 and the second off-axis parabolic mirror 4 is required until the optical path meets the preset requirements. This avoids the situation where the existing off-axis reflective optical path cannot quickly calibrate the optical path, and significantly improves work efficiency.

[0040] Please see Figure 3-4 To obtain the absorbance curve of the near-infrared spectrometer in this embodiment, specifically, a comparative test was conducted using the lens transmission optical path and the off-axis reflection optical path of the present invention, with the optical fibers at both ends being repeatedly plugged and unplugged 3 times each, and the baseline drift range of the absorbance spectrum was recorded. Figure 3 Under the conditions of lens transmission optical path, due to changes in lens positioning, the dispersion also changes during insertion and removal, showing a baseline tilting trend in absorbance changes; while Figure 4 The off-axis reflective baseline is relatively stable, with baseline absorbance variation around 0.015. In other words, the intervention of the first off-axis parabolic mirror 3 and the second off-axis parabolic mirror 4 of this invention can effectively reduce the influence of dispersion effects. Simultaneously, to address the baseline drift caused by repeated fiber insertion and removal, calibration can be achieved simply by sliding the first off-axis parabolic mirror 3 and the second off-axis parabolic mirror 4, significantly improving detection efficiency.

[0041] Furthermore, there are two reflectors 5, and the two reflectors 5 are arranged parallel to each other, so that the first connecting line 71 and the third connecting line 73 are parallel, the second connecting line 72 and the fourth connecting line 74 are parallel, and the second connecting line 72 and the fourth connecting line 74 are connected by a fifth connecting line 75, which passes through the center of the area to be detected in the body 6. Specifically, please refer to... Figure 1By using two parallel reflectors 5 positioned in the middle of the main body 6, the optical path undergoes two additional reflections, adjusting the positions of the first optical fiber 1 and the second optical fiber 2 to their respective horizontal ends, facilitating fiber cabling. Specifically, the lifting angle of the two reflectors 5 is set to 45 degrees, ensuring that, in the conventional cabling configuration where the first optical fiber 1 and the second optical fiber 2 are vertically inserted into the main body 6, the fifth connecting line 75 formed between the two reflectors 5 is perpendicular to the horizontal detection area, facilitating standardized detection. Simultaneously, the sufficient horizontal dimension between the two reflectors 5 also facilitates the placement of the object to be detected, avoiding the problem of cramped detection area space in the main body 1 when the reflectors 5 are not present.

[0042] Furthermore, the first off-axis parabolic mirror 3 has a recessed first screw hole 31 on its outer side facing the body 6. After the first off-axis parabolic mirror 3 moves to a preset position in the first slide groove 61, a first baffle larger than the diameter of the hole in the first slide groove 61 is placed over the first slide groove 61. The first fastener passes through the first baffle and is fixed in the first screw hole 31, thereby fixing the first off-axis parabolic mirror 3. Similarly, the second off-axis parabolic mirror 4 is fixed to the body 6 using the same method, through the combination of the second screw hole 32 and the second cover plate. The above-mentioned mechanical fixing method of fasteners has high maintenance convenience and is simple and easy to disassemble and assemble.

[0043] In another embodiment, the adjusted first off-axis parabolic mirror 3 and second off-axis parabolic mirror 4 can also be fixed by adhesive bonding. Compared with the mechanical fixing method using fasteners, the fixing method in this embodiment is less expensive and can be selected according to actual needs.

[0044] Furthermore, the first off-axis parabolic mirror 3 and the second off-axis parabolic mirror 5 are configured to be identical. Of course, in the optical path system of this embodiment, combined with... Figure 1-2 The overall structure of the main body 6 shown is configured as a rotating mirror structure, which means that the first off-axis parabolic mirror 3 and the second off-axis parabolic mirror 4 are interchangeable, the two reflectors 5 are interchangeable, and even some modules of the main body 6 are interchangeable, which reduces production costs and makes maintenance easier.

[0045] Furthermore, the first off-axis parabolic mirror 3 and the second off-axis parabolic mirror 4 are 90-degree off-axis parabolic mirrors. That is, in this embodiment, the first groove 61 for installing the first off-axis parabolic mirror 3 and the first slot for installing the first optical fiber 1 are set at 90 degrees, and the second groove 62 for installing the second off-axis parabolic mirror 5 and the second slot for installing the second optical fiber 2 are set at 90 degrees. The body 1 as a whole presents a multi-segment vertically bent structure, and the module is easier to process and form.

[0046] It is worth noting that in the main body 6, the first optical fiber 1, the second optical fiber 2, the first off-axis parabolic mirror 3, the second off-axis parabolic mirror 4, and multiple reflectors 5 are all designed to be easily disassembled through sliding grooves, mounting grooves, and slots. The purpose of this is to facilitate later maintenance and to make temporary and convenient fine adjustments to the optical path in order to improve detection efficiency.

[0047] This also includes an embodiment of an application of the optical path system of the present invention for detecting baijiu mash. Since online modeling of samples cannot be performed on the production line before detecting mash with different formulas, offline modeling is required. After modeling, the entire machine is then placed on the production line. Considering baseline tilt, a secondary calibration of the near-infrared model is generally required, affecting production efficiency. In this embodiment, a preset off-axis reflective optical path system is installed at a key point on the production line, and the optical path is calibrated. Then, the key components of the mash are analyzed multiple times. Specifically, the key components of the mash include, but are not limited to, acidity (total acid), protein content, total esters, starch, and moisture content. Because this embodiment uses an off-axis reflective optical path with a more stable baseline, a secondary calibration of the model is not required due to the tilt difference between the baseline and the offline model. Furthermore, each maintenance of the optical path system in this embodiment maintains good consistency, contributing to the stability of the optical path system's detection output. For details on the specific method of this embodiment, please refer to [link to relevant documentation]. Figure 5 .

[0048] The content disclosed above is only a preferred and feasible embodiment of the present invention, and is not intended to limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made using the contents of the present invention specification and drawings are included in the scope of the patent application of the present invention.

[0049] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0050] Although this application has been described by way of examples, those skilled in the art will know that this application has many modifications and variations without departing from the spirit of this application, and it is intended that the appended embodiments include these modifications and variations without departing from this application.

Claims

1. An optical path system for reducing near-infrared spectral baseline tilt; characterized in that, The optical path system for reducing near-infrared spectral baseline tilt includes: The system comprises a first optical fiber, a second optical fiber, a first off-axis parabolic mirror, a second off-axis parabolic mirror, multiple mirrors, and a main body. The free end of the first optical fiber is aligned with the focal point of the first off-axis parabolic mirror. A first connecting line is formed between the first optical fiber and the focal point of the first off-axis parabolic mirror. A second connecting line is formed between the focal point of the first off-axis parabolic mirror and one of the corresponding reflectors. The included angle between the first connecting line and the second connecting line is the same as the off-axis angle of the first off-axis parabolic mirror. The free end of the second optical fiber is aligned with the focal point of the second off-axis parabolic mirror. A third connecting line is formed between the second optical fiber and the focal point of the second off-axis parabolic mirror. A fourth connecting line is formed between the focal point of the second off-axis parabolic mirror and one of the corresponding reflectors. The angle formed between the second connecting line and the fourth connecting line is the same as the off-axis angle of the second off-axis parabolic mirror. The main body has a first groove and a second groove at both ends. The first off-axis parabolic mirror is installed in the first groove and can move back and forth in the first groove. The second off-axis parabolic mirror is installed in the second groove and can move back and forth in the second groove. By moving the first off-axis parabolic mirror and the second off-axis parabolic mirror, the light beam emitted from the free end of the first optical fiber and passing through the first connecting line is reflected by the first off-axis parabolic mirror, the second off-axis parabolic mirror and the plurality of mirrors, and then passes through the third connecting line and is focused by the free end of the second optical fiber.

2. The optical path system for reducing near-infrared spectral baseline tilt according to claim 1, characterized in that: The number of reflectors is two, and the two reflectors are arranged parallel to each other, so that the first connecting line and the third connecting line are parallel, the second connecting line and the fourth connecting line are parallel, and the second connecting line and the fourth connecting line are connected by a fifth connecting line, which passes through the center position of the area to be detected of the body.

3. The optical path system for reducing near-infrared spectral baseline tilt according to claim 1, characterized in that: The first off-axis parabolic mirror has a recessed first screw hole on its outer side facing the main body. When the first off-axis parabolic mirror moves to a preset position in the first slide groove, a first baffle with a size larger than the diameter of the first slide groove hole is installed on the outside of the first slide groove. A first fastener passes through the first baffle and is fixed in the first screw hole, so that the first off-axis parabolic mirror is fixed. The second off-axis parabolic mirror has a recessed second screw hole on its outer side facing the main body. When the second off-axis parabolic mirror moves to a preset position in the second slide groove, a second baffle with a size larger than the diameter of the second slide groove hole is installed on the outside of the second slide groove. A second fastener passes through the second baffle and is fixed in the second screw hole, so that the second off-axis parabolic mirror is fixed.

4. The optical path system for reducing near-infrared spectral baseline tilt according to claim 1, characterized in that: The first off-axis parabolic mirror is fixed in the first groove by adhesive; the second off-axis parabolic mirror is fixed in the second groove by adhesive.

5. The optical path system for reducing near-infrared spectral baseline tilt according to claim 1, characterized in that: The first off-axis parabolic mirror and the second off-axis parabolic mirror are configured to be identical.

6. The optical path system for reducing near-infrared spectral baseline tilt according to claim 1, characterized in that: The first off-axis parabolic mirror and the second off-axis parabolic mirror are 90-degree off-axis parabolic mirrors.

7. The optical path system for reducing near-infrared spectral baseline tilt according to claim 1, characterized in that: The main body includes multiple mounting slots, and multiple reflectors are detachably mounted in the corresponding mounting slots.

8. The optical path system for reducing near-infrared spectral baseline tilt according to claim 1, characterized in that: The main body includes a first slot and a second slot. The first slot is located adjacent to the first off-axis parabolic mirror, and the first optical fiber is detachably inserted into the first slot. The second slot is located adjacent to the second off-axis parabolic mirror, and the second optical fiber is detachably inserted into the second slot.

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