Optical path changing device and optical interference system

Abstract

The present invention discloses an optical path changing device and an optical interference system, comprising a driving motor, a turntable mechanism, a reference arm, a first collimator and a first reflector; the reference arm can rotate integrally with the turntable mechanism; the reference arm comprises a triangular reflector for changing the optical path, and the triangular reflector comprises a first reflective lens, a second reflective lens and a third reflective lens intersecting in pairs. The optical path changing device and the optical interference system disclosed by the present invention can realize continuous change of the optical path, with high efficiency and convenient operation.

Description

Technical Field

[0001] The present invention relates to the field of optical path interference technology, and in particular to an optical path changing device and an optical interference system. Background Art

[0002] The Michelson interferometer is the most common type of optical interferometer. The principle of the Michelson interferometer is that an incident light beam is split into two beams by a beam splitter and then reflected back by the corresponding plane mirror. Because the two beams have the same frequency, the same vibration direction and a constant phase difference (i.e., they meet the interference condition), interference can occur. When the optical path difference between the two beams is within the coherence length range, interference will occur.

[0003] The optical biometer currently used in ophthalmology to measure the axial length of the eye uses this principle. However, in order to take into account the axial resolution, ophthalmic optical biometers generally use a broadband SLD light source with a 3dB bandwidth of 50nm, and its coherence length is only a dozen microns. This requires its reference arm to have the ability to continuously change the optical path to match the micron-level coherence length of the light source.

[0004] At present, in the optical biometer based on the above method, the reference arm changes the optical path by a linear slide rail, the speed of optical path change is slow, and it is difficult to achieve continuous change of the optical path. Summary of the invention

[0005] The object of the present invention is to provide an optical path changing device and an optical interference system which can conveniently change the optical path with high speed, high efficiency and large optical path change range.

[0006] The technical solution of the present invention provides an optical path changing device, comprising a driving motor, a turntable mechanism arranged on the driving motor, at least one reference arm arranged on the turntable mechanism, a first collimator arranged on one side of the turntable mechanism, and a first reflector arranged below the first collimator;

[0007] The reference arm is fixedly mounted on the turntable mechanism and can rotate integrally with the turntable mechanism;

[0008] The reference arm includes a triangular reflector for changing the optical path, and the triangular reflector includes a first reflective lens, a second reflective lens and a third reflective lens intersecting in pairs;

[0009] Among them, when the triangular reflector is in the optical path of the first collimator and the first reflector, the light emitted from the first collimator can be reflected to the first reflector through the first reflective lens, the second reflective lens and the third reflective lens in sequence, and the light reflected by the first reflector can be reflected back to the first collimator through the third reflective lens, the second reflective lens and the first reflective lens in sequence.

[0010] In one of the optional technical solutions, the outgoing light reflected by the third reflective lens to the first reflector is perpendicular to the first reflector.

[0011] In one of the optional technical solutions, the first reflector is perpendicular to the axis of the light hole of the first collimator;

[0012] The outgoing light reflected by the third reflective lens to the first reflector is parallel to the axis of the light hole.

[0013] In one of the optional technical solutions, the first reflective lens, the second reflective lens and the third reflective lens are vertically intersected and connected in pairs;

[0014] The first reflective lens is located on top of the second reflective lens and the third reflective lens;

[0015] Wherein, in the radial direction along the turntable mechanism, the first reflective lens gradually tilts upward from the inside to the outside, and the inner edge and the outer edge of the first reflective lens are respectively parallel to the reference plane of the turntable mechanism;

[0016] In the vertical direction, the light hole of the first collimator is higher than the inner edge of the first reflective lens and lower than the outer edge of the first reflective lens;

[0017] The third reflective lens is connected to the inner edge of the first reflective lens;

[0018] The second reflective lens is connected to a rear end edge of the first reflective lens along the rotation direction of the turntable mechanism.

[0019] In one of the optional technical solutions, the first reflector is mounted on the support portion via a telescopic adjustment mechanism.

[0020] In one of the optional technical solutions, the turntable mechanism includes a circular disc and a mounting boss arranged on the top surface of the circular disc;

[0021] The disk is connected to the output shaft of the driving motor, and the reference arm is installed on the side surface of the mounting boss.

[0022] In one of the optional technical solutions, the reference arm further includes a protective shell, the triangular reflector is installed in the protective shell, and the protective shell is connected to the mounting boss via a fastener.

[0023] In one of the optional technical solutions, the protective shell includes a first plate, a second plate and a third plate that intersect each other in pairs;

[0024] The first reflective lens is bonded to the first plate, the second reflective lens is bonded to the second plate, and the third reflective lens is bonded to the third plate;

[0025] The side surface of the mounting boss has a mounting slope, and in the radial direction of the disk, the mounting slope gradually slopes downward from the inside to the outside;

[0026] The first plate component and the second plate component are respectively provided with connecting ears, each of the connecting ears is respectively connected to the mounting boss through the fastener, and the third plate component is in contact with the mounting inclined surface.

[0027] In one of the optional technical solutions, a plurality of reference arms are evenly distributed on the turntable mechanism at intervals along the circumferential direction.

[0028] The technical solution of the present invention further provides an optical interference system, comprising a light source, a circulator, a detector, a coupler, a second collimator, a second reflector and an optical path changing device as described in any of the above technical solutions;

[0029] The light source, the circulator, the coupler, the second collimator and the second reflector are sequentially arranged at intervals;

[0030] The circulator, the coupler and the second collimator are sequentially connected via optical fibers;

[0031] The circulator and the coupler are respectively connected to the detector via optical fibers;

[0032] The coupler is connected to the first collimator via an optical fiber.

[0033] The above technical solution has the following beneficial effects:

[0034] The optical path changing device and optical interference system provided by the present invention, the turntable mechanism rotates under the drive of the driving motor, the turntable mechanism drives the reference arm to rotate continuously and cyclically, the collimated light of the first collimator first hits the first reflective lens of the triangular reflector, and the first reflective lens reflects the light to the second reflective lens, and then the second reflective lens reflects the light to the third reflective lens, and finally the third reflective lens reflects the light to the first reflector, and the light reflected by the first reflector can return to the first collimator along the original optical path, thereby increasing the optical path. The light returning to the first collimator can enter the coupler to interfere with the first path of light, play a role in enhancing the light signal, and is more easily detected by the detector.

[0035] As the drive motor rotates, the optical path can change by more than 55mm each time it passes through a set of triangular reflectors, and the optical path changes greatly. The drive motor rotates one circle to complete one or more cycles of optical path change. By changing the rotation speed of the drive motor, the optical path change speed and the number of cycles can be increased arbitrarily. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A three-dimensional diagram of an optical path changing device provided by an embodiment of the present invention;

[0037] Figure 2 It is a top view of the reference arm mounted on the turntable mechanism;

[0038] Figure 3 A perspective view of the reference arm mounted on the turntable mechanism;

[0039] Figure 4 A three-dimensional diagram of the turntable mechanism being installed on the drive motor;

[0040] Figure 5 is a perspective view of a reference arm having a triangular reflector and a protective housing;

[0041] Figure 6 The exploded view of the triangular reflector and the protective shell;

[0042] Figure 7 It is a schematic diagram of a first reflector being mounted on a support portion through a telescopic adjustment mechanism;

[0043] Figure 8 A schematic diagram of an optical interference system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. The same components are represented by the same reference numerals. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0045] like Figure 1-3 As shown, an optical path changing device provided by one embodiment of the present invention includes a driving motor 1, a turntable mechanism 2 arranged on the driving motor 1, at least one reference arm 3 arranged on the turntable mechanism 2, a first collimator 4 arranged on one side of the turntable mechanism 2, and a first reflector 5 arranged below the first collimator 4.

[0046] The reference arm 3 is fixedly mounted on the turntable mechanism 2 and can rotate integrally with the turntable mechanism 2 .

[0047] The reference arm 3 includes a triangular reflector 31 for changing the optical path. The triangular reflector 31 includes a first reflector lens 311 , a second reflector lens 312 and a third reflector lens 313 which intersect with each other.

[0048] Among them, when the triangular reflector 31 is in the optical path of the first collimator 4 and the first reflector 5, the light emitted from the first collimator 4 can be reflected to the first reflector 5 through the first reflective lens 311, the second reflective lens 312 and the third reflective lens 313 in sequence, and the light reflected by the first reflector 5 can be reflected back to the first collimator 4 through the third reflective lens 313, the second reflective lens 312 and the first reflective lens 311 in sequence.

[0049] The optical path changing device provided by the present invention is used for continuously changing the optical path.

[0050] The optical path changing device comprises a driving motor 1 , a turntable mechanism 2 , at least one reference arm 3 , a first collimator 4 and a first reflecting mirror 5 .

[0051] The turntable mechanism 2 is mounted on the output shaft of the driving motor 1 . The driving motor 1 is a stepping motor. The driving motor 1 can drive the turntable mechanism 2 to rotate.

[0052] The reference arm 3 is an optical structure, which is used to change the optical path for subsequent interference. The reference arm 3 is fixedly mounted on the turntable mechanism 2, and can rotate integrally with the turntable mechanism 2.

[0053] The reference arm 3 includes a triangular reflector 31 for changing the optical path. The triangular reflector 31 is composed of a first reflector lens 311, a second reflector lens 312 and a third reflector lens 313 which intersect each other.

[0054] The first collimator 4 is located outside the turntable mechanism 2 and is used for light beam collimation.

[0055] The first reflector 5 is located below the first collimator 4 and is used for reflecting the emergent light of the third reflective lens 313 .

[0056] like Figure 1As shown, when the triangular reflector 31 rotates to the optical path between the first collimator 4 and the first reflector 5, the light emitted from the first collimator 4 is emitted to the first reflective lens 311 along the arrow a, and then the first reflective lens 311 reflects the light along the arrow b to the second reflective lens 312, and then the second reflective lens 312 reflects the light along the arrow c to the third reflective lens 313, and finally the third reflective lens 313 reflects the light along the arrow d to the first reflector 5. The first reflector 5 reflects the light against the arrow d to the third reflective lens 313, the third reflective lens 313 reflects the light against the arrow c to the second reflective lens 312, the second reflective lens 312 reflects the light against the arrow b to the first reflective lens 311, and the first reflective lens 311 reflects the light against the arrow a to the first collimator 4.

[0057] The process from the light being emitted from the first collimator 4 to being reflected back to the first collimator 4 is an optical path change cycle. Assuming that the optical path of the light from the first collimator 4 to the first reflective lens 311 is L1, the optical path of the light from the first reflective lens 311 to the second reflective lens 312 is L2, the optical path of the light from the second reflective lens 312 to the third reflective lens 313 is L3, and the optical path of the light from the third reflective lens 313 to the first reflector 5 is L4, then in one optical path change cycle, the changed optical path L=2 (L1+ L2+ L3+L4). The size and angle of the first reflective lens 311, the second reflective lens 312 and the third reflective lens 313 can be set as needed, so that the optical path can change by more than 55mm each time the light path passes through a set of triangular reflectors 31 for reflection, and the optical path change amplitude is large, which can provide a better interference effect.

[0058] Each time the driving motor 1 rotates one circle, one or more cycles of optical path change can be completed. By changing the rotation speed of the driving motor 1, the optical path change speed and the number of cycles can be increased arbitrarily.

[0059] In one embodiment, if Figure 1 As shown, the outgoing light reflected by the third reflective lens 313 to the first reflective mirror 5 is perpendicular to the first reflective mirror 5, so that all light beams directed to the first reflective mirror 5 are reflected back to the third reflective lens 313 by the first reflective mirror 5, and then reflected back to the first collimator 4 by the third reflective lens 313, the second reflective lens 312 and the first reflective lens 311 in sequence.

[0060] The angle or position of the first reflector 5 can be adjusted to ensure that the outgoing light reflected from the third reflective sheet 313 to the first reflector 5 is perpendicular to the first reflector 5 .

[0061] Can be Figure 8 The detector 600 shown is used to determine whether the outgoing light reflected from the third reflective lens 313 to the first reflective mirror 5 is perpendicular to the first reflective mirror 5 .

[0062] The light returning to the first collimator 4 enters the coupler 300 and interferes with the light returning from the second collimator 400 .

[0063] When all the light emitted from the first collimator 4 is reflected back to the first collimator 4 , the interference signal in the coupler 300 is the strongest.

[0064] When the detector 600 detects that the light signal is the strongest, it indicates that the outgoing light reflected from the third reflective lens 313 to the first reflector 5 is perpendicular to the first reflector 5 .

[0065] In one embodiment, if Figure 1 As shown, the first reflector 5 is perpendicular to the axis of the light hole 41 of the first collimator 4, and the outgoing light reflected by the third reflector lens 313 to the first reflector 5 is parallel to the axis of the light hole 41, ensuring that the incident light from the first collimator 4 to the first reflector lens 311 and the outgoing light from the third reflector lens 313 to the first reflector 5 are parallel and perpendicular to the first reflector 5 respectively, so that all the light is reflected back by the first reflector 5.

[0066] The tilt angle of the triangular reflector 31 on the turntable mechanism 2 can be adjusted to ensure that the outgoing light reflected by the third reflector lens 313 to the first reflector 5 is parallel to the axis of the light hole 41 .

[0067] In one embodiment, if Figure 1-3 As shown, the first reflective sheet 311, the second reflective sheet 312 and the third reflective sheet 313 are vertically intersected and connected in pairs.

[0068] The first reflective sheet 311 is located on top of the second reflective sheet 312 and the third reflective sheet 313 .

[0069] In the radial direction along the turntable mechanism 2 , the first reflective lens 311 gradually tilts upward from the inside to the outside, and the inner edge and the outer edge of the first reflective lens 311 are respectively parallel to the reference plane of the turntable mechanism 2 .

[0070] In the vertical direction, the light hole 41 of the first collimator 4 is higher than the inner edge of the first reflective sheet 311 and lower than the outer edge of the first reflective sheet 311 .

[0071] The third reflective sheet 313 is connected to the inner edge of the first reflective sheet 311 .

[0072] The second reflective sheet 312 is connected to the rear end edge of the first reflective sheet 311 along the rotation direction of the turntable mechanism 2 .

[0073] In this embodiment, the included angle of the triangular reflector 31 is a right angle, that is, the first reflective lens 311 , the second reflective lens 312 and the third reflective lens 313 are vertically intersected and connected in pairs.

[0074] During installation, the first reflective lens 311 is located above the second reflective lens 312 and the third reflective lens 313. The third reflective lens 313 is located at the inner edge of the first reflective lens 311. In the rotation direction of the turntable mechanism 2, the end of the first reflective lens 311 and the third reflective lens 313 that first passes through the first collimator 4 is called the front end, and the end that passes through the first collimator 4 later is called the rear end. The second reflective lens 312 is connected to the rear end edges of the first reflective lens 311 and the third reflective lens 313.

[0075] In order to make the light emitted from the first collimator 4 to be directed to the first reflective lens 311, the first reflective lens 311 is arranged tilted, specifically: in the radial direction along the turntable mechanism 2, the first reflective lens 311 gradually tilts upward from the inside to the outside, and the inner edge and the outer edge of the first reflective lens 311 are respectively parallel to the reference plane of the turntable mechanism 2. In other words, the inner edge of the first reflective lens 311 is lower than its outer edge, and the first reflective lens 311 is not tilted in the rotation direction of the turntable mechanism 2. The reference plane of the turntable mechanism 2 can be the top surface of the disk 21 or the ground, which means that the heights of the front and rear end edges of the first reflective lens 311 are consistent.

[0076] The second reflective lens 312 is kept perpendicular to the reference plane of the turntable mechanism 2, and the reflective surface of the third reflective lens 313 is tilted outward and upward.

[0077] In the vertical direction, the light hole 41 of the first collimator 4 is between the inner edge and the outer edge of the first reflective lens 311, so that the light emitted from the first collimator 4 can be emitted to the first reflective lens 311, and then reflected by the second reflective lens 312 and the third reflective lens 313 in sequence, and emitted to the first reflector 5.

[0078] In one embodiment, if Figure 7 As shown, the first reflector 5 is mounted on the support 6 via a telescopic adjustment mechanism 7 .

[0079] The telescopic adjustment mechanism 7 can be a telescopic mechanism such as a screw rod, a cylinder, or an oil cylinder. The telescopic end 71 of the adjustment mechanism 7 is connected to the first reflector 5 to drive the first reflector 5 to move.

[0080] Specifically, the base of the first reflector 5 is connected to the telescopic end 71 .

[0081] As needed, the base of the first reflector 5 is connected to two adjustment mechanisms 7, and the telescopic ends 71 ​​of the two adjustment mechanisms 7 are connected to the diagonals of the base of the first reflector 5. When the telescopic amounts of the two telescopic ends 71 ​​are different, the angle of the first reflector 5 can be adjusted.

[0082] The telescopic end 71 is connected to the base of the first reflector 5 via a ball pin, and the first reflector 5 can swing relative to the telescopic end 71 .

[0083] In one embodiment, if Figure 2-4 As shown, the turntable mechanism 2 includes a circular disk 21 and a mounting boss 22 arranged on the top surface of the circular disk 21 .

[0084] The disk 21 is connected to the output shaft of the driving motor 1 , and the reference arm 3 is mounted on the side of the mounting boss 22 .

[0085] In this embodiment, the turntable mechanism 2 includes a disc 21 and a mounting boss 22. The mounting boss 22 is connected to the top surface of the disc 21. The mounting boss 22 is located in the middle of the disc 21. The reference arm 3 is mounted on the side of the mounting boss 22 by a fastener 23 (such as a bolt).

[0086] In one embodiment, if Figure 1-6 As shown, the reference arm 3 further includes a protective shell 32 , in which the triangular reflector 31 is mounted. The protective shell 32 is connected to the mounting boss 22 via a fastener 23 .

[0087] In this embodiment, by assembling the protection housing 32 on the outer side of the triangular reflector 31, the triangular reflector 31 can be protected. During installation, the protection housing 32 is connected to the mounting boss 22 via the fastener 23.

[0088] In one embodiment, if Figure 1-6 As shown, the protection shell 32 includes a first plate 321, a second plate 322 and a third plate 323 which intersect each other.

[0089] The first reflective lens 311 is bonded to the first plate 321 , the second reflective lens 312 is bonded to the second plate 322 , and the third reflective lens 313 is bonded to the third plate 323 .

[0090] The side surface of the mounting boss 22 has a mounting slope 221 , and in the radial direction of the disk 21 , the mounting slope 221 gradually slopes downward from the inside to the outside.

[0091] The first plate 321 and the second plate 322 are respectively provided with connecting ears 324 . Each connecting ear 324 is connected to the mounting boss 22 via a fastener 23 . The third plate 323 is in contact with the mounting inclined surface 221 .

[0092] In this embodiment, the protective shell 32 is composed of a first plate 321, a second plate 322 and a third plate 323, which are connected in pairs. The first reflective lens 311 is bonded to the bottom surface of the first plate 321, the second reflective lens 312 is bonded to the inner surface of the second plate 322, and the third reflective lens 313 is bonded to the inner surface of the third plate 323. In order to facilitate the assembly of the protective shell 32 and the mounting boss 22, the side of the mounting boss 22 is provided with a mounting inclined surface 221, the top of the mounting boss 22 is narrow and the bottom is wide, so that the mounting inclined surface 221 gradually tilts downward along the radial direction of the disk 21. A mounting hole 222 is respectively opened at a bottom corner and a top corner of the mounting inclined surface 221, and a connecting ear piece 324 is respectively provided on the first plate 321 and the second plate 322, and each connecting ear piece 324 is connected to the mounting boss 22 through a fastener 23, and the end of the fastener 23 is fastened in the mounting hole 222. After installation, the third plate 323 is in contact with the installation inclined surface 221 .

[0093] In one embodiment, if Figure 1-3 As shown, a plurality of reference arms 3 are evenly distributed on the turntable mechanism 2 at intervals along the circumferential direction.

[0094] Multiple reference arms 3 are evenly distributed along the circumferential direction of the turntable mechanism 2. Each time the drive motor 1 drives the turntable mechanism 2 to rotate one circle, each reference arm 3 can change the optical path once, thereby improving the efficiency of changing the optical path and realizing continuous change of the optical path.

[0095] like Figure 8 As shown, an optical interference system provided by an embodiment of the present invention includes a light source 100, a circulator 200, a detector 600, a coupler 300, a second collimator 400, a second reflector 500 and the optical path changing device described in any of the aforementioned embodiments.

[0096] The light source 100, the circulator 200, the coupler 300, the second collimator 400 and the second reflector 500 are sequentially arranged at intervals.

[0097] The circulator 200, the coupler 300 and the second collimator 400 are connected in sequence through optical fibers.

[0098] The circulator 200 and the coupler 300 are connected to the detector 600 via optical fibers, respectively.

[0099] The coupler 300 is connected to the first collimator 4 via an optical fiber.

[0100] The optical interference system provided in this embodiment can be used in medical equipment.

[0101] The optical interference system includes a light source 100, a circulator 200, a detector 600, a coupler 300, a second collimator 400, a second reflector 500 and an optical path changing device.

[0102] For the structure, construction and working principle of the optical path changing device, please refer to the previous description of the optical path changing device, which will not be repeated here.

[0103] The light source 100 is an SLD light source, which is a broadband light source and is used to provide an interference light source.

[0104] The circulator 200 is used to protect the light source 100 to prevent the reflected light from damaging the light source 100 .

[0105] The coupler 300 is used for light splitting and light combining, and the splitting ratio can be set arbitrarily according to needs.

[0106] The second collimator 400 is used to collimate the light beam.

[0107] The second reflector 500 is used to reflect the light emitted from the second collimator 400 back to the second collimator 400 .

[0108] The detector 600 is used to monitor the optical signal.

[0109] The light emitted by the light source 100 passes through the circulator 200 and enters the coupler 300. The coupler 300 divides the light beam into two paths, the first light beam propagates through the second collimator 400, and the second light beam propagates through the first collimator 4. The first light beam is used for actual detection or inspection, such as inspection of the axial length of the eye, and the second light beam is used to change the optical path to interfere with the first light beam transmitted back in the coupler 300, and then the detector 600 can monitor the stronger light signal to facilitate subsequent precise operation.

[0110] After the first light beam and the second light beam interfere in the coupler 300, one light beam is directly transmitted to the detector 600. The other light beam is transmitted to the circulator 200 and then to the detector 600, and no reflected light will be directed to the light source 100. Therefore, the circulator 200 can prevent the reflected light from damaging the light source 100.

[0111] As needed, the above technical solutions can be combined to achieve the best technical effect.

[0112] The above description is only the principle and preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this field, several other modifications can be made based on the principle of the present invention, which should also be considered as the protection scope of the present invention.

Claims

1. An optical path changing device, characterized in that: The optical microscope comprises a driving motor, a turntable mechanism arranged on the driving motor, at least one reference arm arranged on the turntable mechanism, a first collimator arranged on one side of the turntable mechanism, and a first reflecting mirror arranged below the first collimator; The reference arm is fixedly mounted on the turntable mechanism and can rotate integrally with the turntable mechanism; The reference arm includes a triangular reflector for changing the optical path, and the triangular reflector includes a first reflective lens, a second reflective lens and a third reflective lens that intersect each other perpendicularly; The first reflective lens is located on top of the second reflective lens and the third reflective lens; wherein, in the radial direction along the turntable mechanism, the first reflective lens gradually tilts upward from the inside to the outside, and the inner edge and the outer edge of the first reflective lens are respectively parallel to the reference plane of the turntable mechanism; in the vertical direction, the light hole of the first collimator is higher than the inner edge of the first reflective lens and lower than the outer edge of the first reflective lens; The third reflective lens is connected to the inner edge of the first reflective lens, and the reflective surface of the third reflective lens is inclined outward and upward; In the rotation direction of the turntable mechanism, the end of the first reflective lens and the third reflective lens that first passes through the first collimator is called the front end, and the end that passes through the first collimator later is called the rear end, the second reflective lens is connected to the rear end edges of the first reflective lens and the third reflective lens, and the second reflective lens is perpendicular to the reference plane of the turntable mechanism; Wherein, when the triangular reflector is in the optical path between the first collimator and the first reflector, the light emitted from the first collimator can be reflected to the first reflector via the first reflective lens, the second reflective lens and the third reflective lens in sequence, and the light reflected by the first reflector can be reflected back to the first collimator via the third reflective lens, the second reflective lens and the first reflective lens in sequence; The turntable mechanism includes a disc and a mounting boss arranged on the top surface of the disc; the mounting boss is located in the middle of the disc, the disc is connected to the output shaft of the driving motor, the reference arm is mounted on the side of the mounting boss, and three reference arms are evenly distributed on the mounting boss at intervals along the circumferential direction; the reference arm also includes a protective shell, the triangular reflector is mounted in the protective shell, and the protective shell is connected to the mounting boss through a fastener; the top of the mounting boss is narrow and the bottom is wide, and the side of the mounting boss has three mounting inclined surfaces, and in the radial direction along the disc, the mounting inclined surface gradually tilts downward from the inside to the outside, and mounting holes are respectively opened at the bottom corner and the top corner of the mounting inclined surface; The protective shell includes a first plate, a second plate and a third plate that intersect in pairs; the first reflective lens is bonded to the first plate, the second reflective lens is bonded to the second plate, and the third reflective lens is bonded to the third plate; the first plate and the second plate are respectively provided with connecting ears, each of the connecting ears is connected to the mounting boss through the fastener, the fastener connected to the connecting ear of the first plate is fastened in the mounting hole at the top corner, the fastener connected to the connecting ear of the second plate is fastened in the mounting hole at the bottom corner, and the third plate is fitted with the mounting bevel.

2. The optical path changing device according to claim 1, characterized in that: The outgoing light reflected by the third reflective lens to the first reflector is perpendicular to the first reflector.

3. The optical path changing device according to claim 2, characterized in that: The first reflector is perpendicular to the axis of the light hole of the first collimator; The outgoing light reflected by the third reflective lens to the first reflector is parallel to the axis of the light hole.

4. The optical path changing device according to any one of claims 1 to 3, characterized in that: The first reflector is mounted on the support portion through a telescopic adjustment mechanism.

5. An optical interference system, characterized in that: It comprises a light source, a circulator, a detector, a coupler, a second collimator, a second reflector and an optical path changing device as described in any one of claims 1 to 4; The light source, the circulator, the coupler, the second collimator and the second reflector are sequentially arranged at intervals; The circulator, the coupler and the second collimator are sequentially connected via optical fibers; The circulator and the coupler are respectively connected to the detector via optical fibers; The coupler is connected to the first collimator via an optical fiber.

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