Packaging device for changing sensitivity of cylindrical optical sensor by adjusting bias magnetic field

Abstract

The invention discloses a packaging device for changing the sensitivity of a cylindrical optical sensor by adjusting a bias magnetic field, which can be used for improving the sensing performance of an optical magnetic field sensor and comprises a packaging assembly and a cylindrical optical sensor probe mounted in the packaging assembly, and magnetic sheets capable of moving towards each other or in opposite directions are arranged on the packaging assembly and on the two sides of the cylindrical optical sensor probe. According to the invention, two groups of magnetic sheets capable of moving oppositely or oppositely are arranged on two sides of the cylindrical optical sensor probe, so that an adjustable bias magnetic field can be applied, the magnetization process of the probe becomes smooth, the sensing stability of the sensor is improved, the measurement precision is improved, and the measurement sensitivity is adjusted; the principle is simple, and wide popularization is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of optical sensing measurement, and in particular to a packaging device for adjusting a bias magnetic field to change the sensitivity of a cylindrical optical sensor. Background Art

[0002] The optical magnetic field sensor based on the Faraday effect is a high-precision, anti-interference, and wide-spectrum magnetic field measurement technology. The Faraday effect refers to the fact that when passing through a magneto-optical medium in a magnetic field, the deflection angle of linearly polarized light will rotate, and the rotation angle is linearly related to the magnetic field component in the direction of light propagation. Under ideal conditions, the Faraday rotation angle can be expressed as:

[0003] θ=BLV

[0004] Among them, θ represents the Faraday rotation angle, B represents the magnetic induction intensity in the crystal, L represents the length of the crystal, and V represents the Verdet constant of the crystal.

[0005] The basic principle of the sensor is as follows Figure 1 As shown in the figure: After the light passes through the polarizer and becomes linearly polarized light, it enters from one side of the crystal, interacts with the magnetic field inside the crystal to produce deflection, and then exits from the other side, passes through the analyzer, and finally the detector converts the light intensity signal into an electrical signal. The Faraday rotation angle reflects the magnetization intensity in the medium, not the magnetic induction intensity in space.

[0006] According to Malus's law, the intensity of the outgoing polarized light under ideal conditions can be expressed as:

[0007] I 1 =I 0 cos 2 (φ-β)

[0008] Among them, I 0 Represents the intensity of incident polarized light, I 1 represents the intensity of light transmitted through the analyzer, represents the angle between the polarizer and the analyzer transmission axis, and β represents the Faraday rotation angle. When β is small, in order to obtain the highest sensitivity of the system, it is usually taken

[0009] The distribution of magnetization intensity in the crystal is affected by the external magnetic field intensity and the demagnetization field caused by crystal magnetization. For an ellipsoidal uniform medium, the relationship between the medium's magnetization intensity M and the spatial magnetic field intensity H can be expressed as:

[0010] H=χM

[0011] Magnetic domain is a small spontaneous magnetization area widely existing in magnetic materials. The macroscopic magnetization intensity of a crystal is equal to the vector sum of the magnetization intensity of the magnetic domains in all directions:

[0012]

[0013] Where M represents the optical path, N represents the number of magnetic domains in the crystal, and m i represents the magnetization intensity of the i-th magnetic domain, and Vi represents the volume percentage of the i-th magnetic domain.

[0014] Take YIG, a ferrimagnetic crystal commonly used in optical magnetic field sensors, for example. When no external magnetic field is applied, the spontaneous magnetization directions of the magnetic domains in the crystal are different, but because the volumes are equal, the magnetism cancels each other out and does not show magnetism. When a small magnetic field is applied, the volume of the magnetic domains in the same direction as the magnetic field increases rapidly, while the volume proportion of the magnetic domains in other directions decreases. The crystal exhibits magnetism. When the magnetic field continues to increase, the magnetic domains that are different from the magnetic field disappear, and the magnetization direction of the remaining magnetic domains gradually moves toward the direction of the magnetic field. When the magnetic field continues to increase, all magnetic domains gradually point to the direction of the magnetic field, and the crystal magnetization intensity no longer increases with the increase of the external magnetic field, reaching magnetic saturation.

[0015] When the magnetic field is small, the magnetization is in the stage of rapid change in the magnetic domain volume. Since the magnetic domain wall is restricted by the pinning field, its movement is often discontinuous. At this stage, the crystal magnetization intensity changes unevenly, resulting in poor response sensitivity of the sensor.

[0016] Research has found that applying a bias DC magnetic field perpendicular to the direction of light propagation can change the sensor's measurement range and sensing performance. Under a changing external magnetic field, the changes in the magnetic domain state in the crystal include domain wall movement and domain direction rotation. On the one hand, the bias magnetic field can make the magnetic domains in the crystal orderly arranged, so that the magnetic domains only rotate in the direction of the magnetic domains under a changing external magnetic field, improving the stability of the response; on the other hand, due to the nonlinearity, anisotropic magnetization characteristics and magnetic saturation of the crystal, the bias magnetic field perpendicular to the magnetic field measurement direction will also affect the sensor's response.

[0017] For cylindrical crystals, the magnetization intensity inside them is non-uniformly distributed. When a magnetic field is applied in a direction parallel to the axis and perpendicular to the axis, the difficulty of crystal magnetization is quite different. Therefore, applying a bias magnetic field perpendicular to the axial direction of the cylinder will also affect the magnetization characteristics of the crystal along the axial direction, and the degree of influence depends on the strength of the bias magnetic field. Based on this, the present invention proposes a packaging device for adjusting the bias magnetic field to change the sensitivity of a cylindrical optical sensor. Summary of the invention

[0018] The technical problem to be solved by the present invention is: how to change the sensitivity of a cylindrical optical crystal by adjusting the intrinsic magnetization change of the cylindrical optical crystal.

[0019] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0020] A packaging device for adjusting a bias magnetic field to change the sensitivity of a cylindrical optical sensor includes a packaging component and a cylindrical optical sensor probe installed inside the packaging component. Magnetic sheets capable of moving toward or away from each other are installed on the packaging component and on both sides of the cylindrical optical sensor probe.

[0021] The present application installs two groups of magnetic sheets that can move toward or away from each other on both sides of a cylindrical optical sensor probe, thereby applying an adjustable bias magnetic field to smooth the magnetization process of the probe, improve the sensing stability of the sensor, increase the measurement accuracy, and adjust the measurement sensitivity. The principle is simple and easy to promote widely.

[0022] As a further solution of the present invention: a driving component for driving the two magnetic sheets to move is installed on the packaging component.

[0023] As a further solution of the present invention: the driving assembly includes a driving gear installed on the back of the packaging assembly, and the upper and lower ends of the driving gear are meshed and connected with driven racks, and the ends of the driven racks are connected to the two sets of magnetic sheets through sliding rods.

[0024] As a further solution of the present invention: a slide groove for moving the magnetic sheet is provided on the packaging component, and the slide rod can pass through the slide groove to connect with the magnetic sheet.

[0025] As a further solution of the present invention: the driving assembly uses two groups of linear cylinders, the two groups of linear cylinders are respectively connected to the two groups of magnetic sheets, and can drive the two groups of magnetic sheets to move towards or in opposite directions.

[0026] As a further solution of the present invention: the driving cylinder adopts two sets of ball screws, the two sets of ball screws are respectively connected to the two sets of magnetic sheets, and can drive the two sets of magnetic sheets to move towards or in opposite directions.

[0027] As a further solution of the present invention: two groups of magnetic sheets are symmetrically arranged on both sides of the cylindrical optical sensor probe.

[0028] As a further solution of the present invention: the packaging assembly includes a lower packaging cover plate and an upper packaging cover plate buckled and connected thereto, wherein the lower packaging cover plate is provided with a mounting groove, a lower sensing probe mounting groove is provided in the middle, and the upper packaging cover plate is provided with a mounting convex buckle, a upper sensing probe mounting groove is provided in the middle;

[0029] The cylindrical optical sensor probe is placed between the lower sensing probe installation groove and the upper sensing probe installation groove, and the installation groove can be engaged with the installation convex buckle.

[0030] As a further solution of the present invention: both sides of the lower packaging cover plate are provided with sunken outer bearing plates, and movable magnetic sheet clamps are installed on the outer bearing plates, and the magnetic sheet is installed in the magnetic sheet clamps.

[0031] As a further solution of the present invention: the magnetic sheets protrude from the top of the magnetic sheet clamp, and the two groups of magnetic sheets apply a magnetic field in a direction perpendicular to the cylindrical optical sensor probe.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The present application installs two groups of magnetic sheets that can move toward or in opposite directions on both sides of a cylindrical optical sensor probe, thereby applying an adjustable bias magnetic field, improving the magnetization smoothness of the crystal in the measurement magnetic field, thereby improving the stability of the sensor and the measurement accuracy. By adjusting the distance between the permanent magnet and the crystal and changing the bias magnetic field strength at the crystal, the sensitivity of the sensor can be adjusted. The present invention is mainly applicable to improving the magnetization change of the optical crystal caused by the external magnetic field, improving the sensor accuracy, adjusting the sensor sensitivity, and being safe and efficient.

[0034] 2. The present application can be provided with a driving gear and a driven rack, and the driven rack is connected to the magnetic sheet through a slide bar. By adjusting the driving gear, the two driven racks can be driven to rotate, and the driving cooperation between the rack and the gear changes the distance between the two magnetic sheets. The gear and rack have high accuracy, thereby improving the measurement accuracy.

[0035] 3. The present application also uses a linear cylinder to change the distance between the two magnetic sheets. The linear cylinder has a high movement accuracy, which can improve the measurement accuracy.

[0036] 4. The present application also uses a linear cylinder to change the distance between the two magnetic sheets. The linear cylinder has a high movement accuracy, which can improve the measurement accuracy.

[0037] 5. The present application sets an upper packaging cover plate and a lower packaging cover plate, and the upper packaging cover plate and the lower packaging cover plate can encapsulate the cylindrical optical sensor probe inside the two, and the upper and lower packaging top covers are used to encapsulate the sensor probe in a one-to-one correspondence manner between the grooves and the protrusions, thereby reducing the interference of the external environment on the sensor unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The sensor principle involved in the background of the present invention;

[0039] Figure 2 It is a structural schematic diagram of a packaging device according to an embodiment of the present invention;

[0040] Figure 3 This is a schematic structural diagram of a lower package cover plate according to an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the structure of the packaging cover plate in an embodiment of the present invention;

[0042] Figure 5 A schematic structural diagram of the packaging cover plate from another perspective according to an embodiment of the present invention;

[0043] Figure 6 This is a schematic structural diagram of a cylindrical optical sensor probe according to an embodiment of the present invention;

[0044] Figure 7 This is a schematic diagram of the specific structure of a cylindrical optical sensor probe according to an embodiment of the present invention;

[0045] Figure 8 Schematic diagram of the effect of bias magnetic fields of different strengths on sensor response in Example 1 of the present invention;

[0046] Fig. 9 is a magneto-optical response characteristic curve diagram of a cylindrical optical sensor probe according to an embodiment of the present invention;

[0047] Description of reference numerals:

[0048] 1. Lower packaging cover plate; 101. Lower sensor probe mounting groove; 102. Mounting groove;

[0049] 2. External bearing plate; 201. Slide groove; 202. Slide rod; 203. Driven rack; 204. Driving gear;

[0050] 3. Permanent magnet magnetic sheet;

[0051] 4. Magnetic clip;

[0052] 5. Upper packaging cover; 501. Upper sensing probe mounting slot; 502. Mounting convex buckle;

[0053] 6. Cylindrical optical sensor probe; 61. First optical fiber collimator; 62. First polarizer; 63. Cylindrical YIG crystal; 64. Ring-shaped cylindrical YIG crystal; 65. Second polarizer; 66. Second optical fiber collimator. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] Example 1

[0056] Reference Figure 2 , Figure 3 , Figure 4 as well as Figure 5 , a packaging device for adjusting the bias magnetic field to change the sensitivity of a cylindrical optical sensor can be used to improve the sensing performance of an optical magnetic field sensor, comprising a lower packaging cover plate 1, an outer supporting plate 2, a permanent magnet magnetic sheet 3, a magnetic sheet clamp 4, an upper packaging cover plate 5 and a cylindrical optical sensor probe 6, wherein the cylindrical optical sensor probe 6 can be packaged between the lower packaging cover plate 1 and the upper packaging cover plate 5, the outer supporting plate 2 is placed on both sides of the lower packaging cover plate 1, and the permanent magnet magnetic sheet 3 is installed on the outer supporting plate 2 on both sides. By adjusting the distance between the two permanent magnet magnetic sheets 3, the intensity of the bias magnetic field to which the cylindrical optical sensor probe 6 is subjected can be changed, thereby achieving control of the sensor sensitivity.

[0057] Reference Figure 2 and Figure 4 The lower packaging cover plate 1 has an "I"-shaped structure in the middle, and outer bearing plates 2 are integrally formed on both sides of the middle of the lower packaging cover plate 1. A lower sensor probe mounting groove 101 for accommodating a cylindrical optical sensor probe 6 is provided in the vertical direction in the middle of the lower packaging cover plate 1, while both ends of the lower sensor probe mounting groove 101 are not blocked; mounting grooves 102 for buckling with the upper packaging cover plate 5 are also provided on the lower packaging cover plate 1 and on both sides of the lower sensor probe mounting groove 101.

[0058] Reference Figure 2 and Figure 3 The upper package cover plate 5 is in an “I”-shaped structure as a whole, which corresponds to the middle position of the lower package cover plate 1. The upper package cover plate 5 can cooperate with the lower package cover plate 1 to package the cylindrical optical sensor probe 6 between the two;

[0059] Furthermore, an upper packaging probe mounting groove 501 for accommodating the cylindrical optical sensor probe 6 is provided in the vertical direction in the middle position of the upper packaging cover plate 5, and both ends of the upper packaging probe mounting groove 501 are not blocked; the upper packaging probe mounting groove 501 and the lower packaging probe mounting groove 101 just form a groove body for encapsulating the cylindrical optical sensor probe 6, and mounting protrusions 502 for snapping into the lower packaging cover plate 1 are also provided on the upper packaging cover plate 5 and on both sides of the upper packaging probe mounting groove 501, and the mounting protrusions 502 correspond to the mounting grooves 102 in position, shape and size, and the mounting protrusions 502 can just snap into the mounting grooves 102, thereby realizing the connection and fixation between the upper packaging cover plate 5 and the lower packaging cover plate 1.

[0060] Reference Figure 2 and Figure 4, the bottom of the outer bearing plate 2 is flush with the bottom of the lower packaging cover plate 1, the top of the outer bearing plate 2 is sunken compared to the top of the lower packaging cover plate 1, the two groups of permanent magnet magnetic sheets 3 and the cylindrical optical sensor probe 6 are on the same horizontal plane, and the cylindrical optical sensor probe 6 is located in the middle of the two groups of permanent magnet magnetic sheets 3; a magnetic sheet clamp 4 is arranged on the top of the two outer bearing plates 2 perpendicular to the direction of the outer bearing plates 2, and a permanent magnet magnetic sheet 3 is installed inside the magnetic sheet clamp 4, and the permanent magnet magnetic sheet 3 protrudes from the top of the magnetic sheet clamp 4; a slide groove 201 that can move relative to the cylindrical optical sensor probe 6 is opened on the two outer bearing plates 2, and the slide groove 201 is equivalent to being arranged vertically with the lower sensor probe installation groove 101;

[0061] A driving gear 204 is arranged at the middle position of the back of the lower packaging cover plate 1, and the upper and lower ends of the driving gear 204 are meshed with driven racks 203, and the ends of the driven racks 203 are connected to the two groups of magnetic film clamps 4 through the sliding rods 202; therefore, by controlling the driving gear 204, the two groups of driven racks 203 can be driven to move toward or oppositely, and the driven racks 203 then drive the slider 202 to pull the magnetic film clamps 4 to move along the slide groove 201, and the two groups of magnetic film clamps 4 then drive the two groups of permanent magnet magnetic sheets 3 to move toward or oppositely, thereby adjusting the distance between the two permanent magnet magnetic sheets 3 to change the strength of the bias magnetic field received by the cylindrical optical sensor probe 6, thereby realizing the control of the sensor sensitivity.

[0062] Applying different bias magnetic fields to the cylindrical YIG crystal in the sensor probe, the sensor response characteristics are as follows: Figure 8 As shown; Figure 8 The characteristics of the sensor output light intensity changing with the external magnetic field strength under different bias magnetic field strengths are plotted. b is the bias magnetic field strength, φ a is the angle between the polarizer and the analyzer in the sensing light path; the ordinate is the output light intensity of the sensor. When the angle between the polarizer and the analyzer in the sensing light path is φ a When the value is ﹢45° or -45°, the sensor output light intensity shows opposite trends with the change of the external magnetic field. Under the condition of zero external magnetic field, the two angles φ a The output light intensity of the value situation is the same. Since the output light signal of the sensor is linearly converted into an electrical signal output by the photodetector, the output light intensity is proportional to the output voltage signal of the sensor; the slope of the curve in the figure represents the rate of change of the sensor output signal with the external magnetic field. The higher the absolute value of the slope of the curve, the greater the change of the sensor output signal under the same external magnetic field change, and the higher the sensitivity of the sensor. As the intensity of the bias magnetic field changes, the slope of the sensor response curve, that is, the sensitivity, also changes.

[0063] The present application uses two NdFeB permanent magnets 3 to generate a bias magnetic field. Since the volume of the YIG crystal is much smaller than that of the magnet, it is approximately considered that the crystal is in a parallel bias magnetic field in the two magnets. During use, the distance between the two magnets is changed to generate bias magnetic fields of different sizes to achieve sensitivity adjustment of the sensor.

[0064] like Figure 6 and Figure 7 As shown, the cylindrical optical sensor probe 6 includes: a first optical fiber collimator 11, a first polarizer 12, a cylindrical YIG crystal 13, a ring-shaped cylindrical YIG crystal 14, a second polarizer 15, and a second optical fiber collimator 16;

[0065] The input end of the first fiber collimator 11 is connected to the fiber laser through an optical fiber, the output end of the first fiber collimator 11 is closely connected to one side of the first polarizer 12, the other side of the first polarizer 12 is closely connected to the input end of the cylindrical YIG crystal 13, the output end of the cylindrical YIG crystal 13 is closely connected to one side of the second polarizer 15, the other side of the second polarizer 15 is closely connected to the input end of the second fiber collimator 16, and the output end of the second fiber collimator 16 is connected to the photodetector through an optical fiber. The annular cylindrical YIG crystal 14 is sleeved on the outside of the cylindrical YIG crystal 13, the annular cylindrical YIG crystal 14 is coaxial with the cylindrical YIG crystal 13, the inner diameter of the annular cylindrical YIG crystal 14 is equal to the diameter of the cylindrical YIG crystal 13, and the length of the annular cylindrical YIG crystal 14 is equal to the length of the cylindrical YIG crystal 13; the Gaussian diameter of the output light beam of the first optical fiber collimator 11 is equal to the diameter of the cylindrical YIG crystal 13, so that the response waveform of the sensor does not show obvious distortion.

[0066] Preferably, the included angle between the first polarizer 12 and the second polarizer 15 in the transmission direction is 45°.

[0067] The sensor works as follows:

[0068] In this embodiment, the wavelength of the incident light is 1310nm. After the light beam is emitted through the first optical fiber collimator 11, the light beam emitted from the first optical fiber collimator 11 is approximately parallel light with a Gaussian diameter of 1mm. The light beam then passes through the first polarizer 12 with a size of 3mm*3mm*0.2mm to form linearly polarized light. The linearly polarized light enters a cylindrical YIG crystal 13 with a diameter of 1mm and a length of 2.5mm, and the polarization direction rotation angle of the linearly polarized light caused by the Faraday effect in the cylindrical YIG crystal 13 is proportional to the component of the magnetic field parallel to the light transmission direction. After the linear polarized light is rotated in polarization direction by the cylindrical YIG crystal 13, it is transmitted through the second polarizer 15 with a size of 3mm*3mm*0.2mm and enters the second optical fiber collimator 16; the annular cylindrical YIG crystal 14 has an outer diameter of 5mm, an inner diameter of 1mm, a length of 2.5mm, and a light-absorbing coating is coated on the surface; after the annular cylindrical YIG crystal 14 is sleeved on the outside of the cylindrical YIG crystal 13, the magnetization intensity distribution of the cylindrical YIG crystal 13 and the annular cylindrical YIG crystal 14 is equivalent to that of a cylindrical YIG crystal with a diameter of 5mm and a length of 2.5mm.

[0069] The magnetization in the inner cylindrical YIG crystal 13 used in this embodiment is affected by the outer annular cylindrical YIG crystal 14, and the two are equivalent to a low aspect ratio cylindrical YIG crystal, thereby improving the linearity of the magneto-optical response characteristic curve; the equivalent aspect ratio D1 of the cylindrical YIG crystal 13 and the annular cylindrical YIG crystal 14 is: 2.5mm / 5mm=0.5; if a cylindrical YIG crystal with a diameter of 1mm and a length of 2.5mm is directly used, its aspect ratio D2 is: 2.5mm / 1mm=2.5. Obviously, D1 is only 1 / 5 of D2, so a more highly linear response characteristic can be obtained.

[0070] like Fig. 9 As shown, it is a magneto-optical response characteristic curve diagram of the optical magnetic field sensor based on the YIG crystal according to an embodiment of the present invention. From the figure, it can be seen that the linearity of the response curve of the sensor is significantly improved after the circular cylindrical YIG crystal 14 is installed.

[0071] In order to improve the linearity of the response characteristic curve of the sensor, it is necessary to reduce the aspect ratio of the YIG crystal; in order to suppress the distortion in the response waveform, it is necessary to ensure that the Gaussian diameter of the light beam is close to the diameter of the cylindrical YIG crystal, but it is very difficult to increase the Gaussian diameter of the light beam; the present invention can ensure that the Gaussian diameter of the light beam is close to the diameter of the cylindrical YIG crystal under a smaller Gaussian diameter of the light beam, so that the response waveform of the sensor does not show obvious distortion; at the same time, the response characteristic curve of the sensor is regulated by installing an outer ring-shaped YIG crystal, thereby improving the linearity of the response curve.

[0072] Example 2

[0073] The rest is the same as Example 1, except that, in Example 2, two groups of linear cylinders can be selected to be used for the movement of two permanent magnet pieces 3. The two groups of linear cylinders are respectively connected to the two groups of magnetic pieces, and can drive the two groups of magnetic pieces to move toward or oppositely. The two groups of linear cylinders can be installed on the back of the lower packaging cover plate 1, or on the sides of the two permanent magnet pieces 3. The specific installation position is not limited in this application, and only two of the installation methods are given for reference.

[0074] Example 3

[0075] The rest is the same as Example 1, except that, in Example 2, two sets of ball screws can be selected to move the two permanent magnet pieces 3, and the two sets of ball screws are respectively connected to the two sets of magnetic pieces, and can drive the two sets of magnetic pieces to move toward or oppositely, and the two sets of ball screws can be installed on the back of the lower packaging cover 1, or on the sides of the two permanent magnet pieces 3. The specific installation position is not limited in this application, and only two of the installation methods are given for reference.

[0076] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A packaging device for adjusting the bias magnetic field to change the sensitivity of a cylindrical optical sensor, characterized in that: The invention comprises a packaging component and a cylindrical optical sensor probe (6) installed inside the packaging component, wherein magnetic sheets capable of moving toward or in opposite directions are installed on the packaging component and on both sides of the cylindrical optical sensor probe (6).

2. The packaging device for adjusting the bias magnetic field to change the sensitivity of a cylindrical optical sensor according to claim 1, characterized in that: A driving component for driving the two magnetic sheets to move is installed on the packaging component.

3. The packaging device for adjusting the bias magnetic field to change the sensitivity of a cylindrical optical sensor according to claim 2, characterized in that: The driving assembly comprises a driving gear (204) mounted on the back of the packaging assembly, the upper and lower ends of the driving gear (204) are meshedly connected with a driven rack (203), and the ends of the driven rack (203) are connected to two sets of magnetic sheets through a sliding rod (202).

4. The packaging device for adjusting the bias magnetic field to change the sensitivity of a cylindrical optical sensor according to claim 3, characterized in that: A slide groove (201) for moving the magnetic sheet is provided on the packaging component, and the slide rod (202) can pass through the slide groove (201) to be connected to the magnetic sheet.

5. The packaging device for adjusting the bias magnetic field to change the sensitivity of a cylindrical optical sensor according to claim 2, characterized in that: The driving assembly adopts two groups of linear cylinders, which are respectively connected to two groups of magnetic sheets and can drive the two groups of magnetic sheets to move towards or in opposite directions.

6. The packaging device for adjusting the bias magnetic field to change the sensitivity of a cylindrical optical sensor according to claim 2, characterized in that: The driving cylinder adopts two sets of ball screws, which are respectively connected to two sets of magnetic sheets and can drive the two sets of magnetic sheets to move towards or in opposite directions.

7. The packaging device for adjusting the bias magnetic field to change the sensitivity of a cylindrical optical sensor according to claim 1, characterized in that: The two groups of magnetic sheets are symmetrically arranged on both sides of the cylindrical optical sensor probe (6).

8. The packaging device for adjusting the bias magnetic field to change the sensitivity of a cylindrical optical sensor according to claim 1, characterized in that: The packaging assembly comprises a lower packaging cover plate (1) and an upper packaging cover plate (5) buckled and connected thereto, wherein the lower packaging cover plate (1) is provided with a mounting groove (102) and a lower sensing probe mounting groove (101) is provided in the middle, and the upper packaging cover plate (5) is provided with a mounting convex buckle (502) and an upper sensing probe mounting groove (501) is provided in the middle; The cylindrical optical sensor probe (6) is placed between the lower sensing probe mounting groove (101) and the upper sensing probe mounting groove (501), and the mounting groove (102) can be buckled with the mounting protrusion (502).

9. The packaging device for adjusting the bias magnetic field to change the sensitivity of a cylindrical optical sensor according to claim 8, characterized in that: Both sides of the lower packaging cover plate (1) are provided with sunken outer bearing plates (2), and a movable magnetic sheet clamp (4) is installed on the outer bearing plate (2), and the magnetic sheet is installed in the magnetic sheet clamp (4).

10. The packaging device for adjusting the bias magnetic field to change the sensitivity of a cylindrical optical sensor according to claim 9, characterized in that: The magnetic sheets protrude from the top of the magnetic sheet clamp (4), and the two groups of magnetic sheets apply a magnetic field in a direction perpendicular to the cylindrical optical sensor probe (6).

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