A pendulum Fourier transform spectrometer

Abstract

The application discloses a pendulum Fourier transform spectrometer, a light beam entering a beam splitting prism is divided into two beams in the form of reflection and transmission, wherein the reflected beam splitting beam A is reflected by a mirror A again, penetrates the beam splitting prism and enters a detector; wherein the transmitted beam splitting beam B is reflected by a mirror B, is reflected by the beam splitting prism again, enters the detector and interferes with the light beam A, the mirror B is fixed to a movable end of a pendulum mechanism, the movable end of the pendulum mechanism reciprocates along the direction of approaching and leaving the beam splitting prism under the periodic pushing of a driver, and carries the mirror B which is always perpendicular to the direction of the light beam B. The driver is separated from the mirror B by arranging the pendulum mechanism, the stability of the mirror B is affected by the pendulum mechanism, and the pendulum mechanism only reciprocates around a rotating shaft under the traction of a heavy hammer on a rod / line, so that the structure and movement form of the pendulum mechanism are simpler than those of the driver, and therefore the reliability can be obviously improved.

Description

A pendulum Fourier transform spectrometer Technical Field

[0001] This invention relates primarily to the field of spectrometer technology, and more particularly to a pendulum Fourier transform spectrometer. Background Technology

[0002] In traditional Fourier transform infrared spectrometers, the Michelson interferometer is widely used. It mainly consists of a fixed mirror, a moving mirror, a beam splitter, and a moving mirror drive mechanism. Figure 1 illustrates the basic working principle of a conventional Michelson interferometer: a beam emitted from a light source S is split into two beams by a beam splitter G, through reflection and transmission. The beam formed by reflection is reflected again by mirror M1 and then passes through beam splitter G into detector D. The beam formed by transmission is reflected again by mirror M2 and then by beam splitter G into detector D. If the two beams meet the interference conditions, interference fringes are formed. In this device, mirror M1 is the moving mirror, mirror M2 is the fixed mirror, M2' is the mirror image of mirror M2 along beam splitter G, and h represents the distance between mirror M1 and mirror M2 during their movement. It is evident that mirror M1 is the only continuously moving component in this device, and the accuracy and stability of its movement directly determine the performance of the instrument.

[0003] In existing Fourier transform infrared spectrometers, the reflector M1 is often fixed to the actuator and reciprocates with it. Therefore, the motion accuracy and stability of the reflector M1 are entirely determined by the performance of the actuator, placing extremely high demands on its reliability. However, in reality, the actuator cannot eliminate motion errors. When these errors accumulate during repetitive motion, they can easily produce deflections sufficient to affect the detection results, making it difficult to meet the quality requirements of the reconstructed spectrum. Therefore, an auxiliary structure must be designed to separate the reflector M1 from the actuator, preventing the actuator's errors from being transmitted to and accumulating in the reflector M1. This reduces the reliability requirements of the actuator and improves the overall stability of the device. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a pendulum Fourier transform spectrometer.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A pendulum-type Fourier transform spectrometer splits a beam of light incident on a beam splitter into two beams through reflection and transmission. The reflected beam A is reflected again by mirror A and then passes through the beam splitter into a detector. The transmitted beam B is reflected again by mirror B and then by the beam splitter into a detector, where it interferes with beam A. Mirror B is fixed to the movable end of a pendulum mechanism. Under the periodic push of a driver, the movable end of the pendulum mechanism carries mirror B, which is always perpendicular to the beam B, and swings back and forth along a direction approaching and moving away from the beam splitter.

[0007] As a further improvement to the above technical solution:

[0008] The spectrometer includes a processing module, which is connected to the detector and the driver signals respectively.

[0009] The driver includes a movable shaft for periodically pushing the pendulum mechanism and a grating ruler for acquiring real-time displacement information of the movable shaft.

[0010] The contact surfaces of the driver and the pendulum mechanism are both fixed with magnetic components, and the magnetic components on the driver and the magnetic components on the pendulum mechanism repel each other.

[0011] The contact surface between the driver and the pendulum mechanism is provided with an elastic element.

[0012] The driving direction of the actuator is parallel to that of beam B.

[0013] The pendulum mechanism includes two pairs of identical bearing assemblies; each bearing assembly consists of a fixed bearing located at the top and a movable bearing located at the bottom and swinging around the fixed bearing, connected by a longitudinal rod; each fixed bearing is located at the same height, and each movable bearing is connected by a crossbar, on the side of the crossbar away from the driver, a reflector B is fixed.

[0014] The pendulum mechanism includes two pairs of identical bearing groups; each bearing group includes a pair of fixed bearings located above, and each fixed bearing is connected by a vertical rod to a movable bearing located below and swinging around the corresponding fixed bearing; each fixed bearing is distributed at the apex of a parallelogram on a horizontal plane, and the movable bearings located on the same side in different bearing groups are connected by a connecting rod, and the two connecting rods are connected by a horizontal rod, and a reflector B is fixed on the side of the horizontal rod away from the driver.

[0015] The pendulum mechanism includes four fixed bearings distributed at the apex of a parallelogram on a horizontal plane. Each fixed bearing is hinged to a vertical rod with a free end that can swing around it. The free ends of each vertical rod are connected in sequence by connecting rods. Each of the two connecting rods arranged along the direction of beam B is hinged to a movable bearing. The two movable bearings are connected by a crossbar. A reflector B is fixed to the side of the crossbar away from the driver.

[0016] Compared with the prior art, the advantages of the present invention are as follows:

[0017] By incorporating a pendulum mechanism with reflector B, the actuator is not directly connected to reflector B, and the contact between the actuator and the pendulum mechanism is periodic and brief. This makes it difficult for the motion error generated by the actuator to accumulate in the pendulum mechanism, thus making it difficult to drive reflector B to deflect. In other words, compared to the existing technology where reflector B is directly fixed to the actuator and the stability of reflector B4 is directly determined by the actuator, the technical solution disclosed in this application separates the actuator from reflector B by incorporating a pendulum mechanism. The stability of reflector B is then affected by the pendulum mechanism. Since the pendulum mechanism is simply a weight reciprocating around an axis under the influence of a rod / line, its structure and motion are simpler than those of the actuator, thus significantly improving reliability. Attached Figure Description

[0018] Figure 1 is a schematic diagram of the basic working principle of the Michelson interferometer in the prior art;

[0019] Figure 2 is a schematic diagram of the structure of a pendulum Fourier transform spectrometer;

[0020] Figure 3 is a schematic diagram of the pendulum mechanism in Embodiment 1;

[0021] Figure 4 is a schematic diagram of the pendulum mechanism (including the driver) in Embodiment 2;

[0022] Figure 5 is a schematic diagram of the pendulum mechanism in Embodiment 3.

[0023] The labels in the diagram represent: 1. Beam splitter prism; 2. Reflector A; 3. Detector; 4. Reflector B; 5. Pendulum mechanism; 51. Bearing assembly; 511. Fixed bearing; 512. Vertical rod; 513. Movable bearing; 514. Horizontal rod; 515. Connecting rod; 6. Driver; 7. Processing module; 8. Magnetic component;

[0024] a1, beam; a2, beam A; a3, beam B. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Example 1

[0027] As shown in Figures 2 and 3, in this embodiment of the pendulum Fourier transform spectrometer, the light beam a1 incident on the beam splitter prism 1 is split into two beams by reflection and transmission. The beam Aa2 formed by reflection is reflected again by mirror A2 and then passes through the beam splitter prism 1 into the detector 3. The beam Ba3 formed by transmission is reflected by mirror B4 and then reflected again by the beam splitter prism 1 into the detector 3, where it interferes with the beam Aa2. Mirror B4 is fixed to the movable end of the pendulum mechanism 5. Under the periodic push of the driver 6, the movable end of the pendulum mechanism 5 carries mirror B4, which is always perpendicular to the direction of beam Ba3, and swings back and forth in a direction close to and away from the beam splitter prism 1. The driver 6 periodically applies a brief thrust to the movable end of the pendulum mechanism 5, causing the pendulum mechanism 5 to maintain its swinging state under the action of the thrust. Since mirror B4 is fixed to the movable end of the pendulum mechanism 5, mirror B4 can swing synchronously with the movable end of the pendulum mechanism 5 during the movement of the pendulum mechanism 5. Reflector B4 is a plane mirror and remains perpendicular to the beam Ba3 during its oscillation. The oscillation of reflector B4 involves a partial motion along the direction of approaching and moving away from beam splitter 1. This ensures that the reflected light remains parallel to the incident light while simultaneously altering the distance between reflector B4 and reflector A2 along the mirror image of beam splitter 1, thus changing the interference fringes. By incorporating a pendulum mechanism 5 that houses reflector B4, the actuator 6 is not directly connected to reflector B4, and the contact between the actuator 6 and the pendulum mechanism 5 is periodic and brief. This prevents the motion error generated by the actuator 6 from accumulating on the pendulum mechanism 5, thereby hindering the deflection of reflector B4. In other words, compared to the existing technology where the reflector B4 is directly fixed to the driver 6 and the stability of the reflector B4 is directly determined by the driver 6, the technical solution disclosed in this application separates the driver 6 from the reflector B4 by setting a pendulum mechanism 5. The stability of the reflector B4 is then affected by the pendulum mechanism 5. Since the pendulum mechanism 5 is simply a weight reciprocating around the axis under the pull of a rod / line, its structure and motion are simpler than those of the driver 6, so the reliability can be significantly improved.

[0028] Specifically, beam a1, beam Aa2, and beam Ba3 are all horizontal beams.

[0029] In this embodiment, the spectrometer includes a processing module 7, which is signal-connected to both the detector 3 and the driver 6. By configuring the processing module 7, a structural basis is provided for storing and calculating the interference information generated by the split beams Aa2 and Ba3 acquired by the detector 3. Furthermore, the signal connection between the driver 6 and the processing module 7 enables the processing module 7 to issue adjustment commands to the driver 6 based on the calculated structure, thus forming a feedback mechanism.

[0030] In this embodiment, the driver 6 includes a movable shaft for periodically pushing the pendulum mechanism 5 and a grating ruler for acquiring real-time displacement information of the movable shaft. By setting the grating ruler, the real-time displacement of the movable shaft can be accurately detected, thereby providing feedback to the processing module 7 and providing information support for the formation of adjustment commands.

[0031] In this embodiment, magnetic elements 8 are fixed to the contact surfaces of the actuator 6 and the pendulum mechanism 5, and the magnetic elements 8 on the actuator 6 and the pendulum mechanism 5 repel each other. To reduce or avoid the accumulation of motion errors of the actuator 6 on the pendulum mechanism 5, which could affect the stability of the reflector B4, a magnetic element 8 is installed on the contact surfaces of both the actuator 6 and the pendulum mechanism 5. The like poles of the two magnetic elements 8 face each other, generating a repulsive force. When the pendulum mechanism 5 moves towards the actuator 6, the actuator 6 can push the movable end of the pendulum mechanism 5 away under the action of the repulsive force, thus completing the force application of the actuator 6 to the pendulum mechanism 5. Due to the repulsive force, the contact time between the actuator 6 and the pendulum mechanism 5 is shortened, and even contactless force transmission can be achieved, thereby reducing or avoiding the accumulation of motion errors of the actuator 6 on the pendulum mechanism 5 and improving the stability of the reflector B4.

[0032] In this embodiment, an elastic element is provided at the contact surface between the actuator 6 and the pendulum mechanism 5. To reduce the accumulation of motion error of the actuator 6 on the pendulum mechanism 5, which could affect the stability of the reflector B4, an elastic element is provided at the contact surface between the actuator 6 and the pendulum mechanism 5. When the pendulum mechanism 5 moves towards the actuator 6 and contacts the elastic element, or when the actuator 6 or the pendulum mechanism 5 contacts the elastic element, the pendulum mechanism 5 is pushed away in the opposite direction by the elastic force of the elastic element, thus completing the force applied by the actuator 6 to the pendulum mechanism 5. Due to the elastic force, the contact time between the actuator 6 and the pendulum mechanism 5 is shortened, thereby reducing the accumulation of motion error of the actuator 6 on the pendulum mechanism 5 and improving the stability of the reflector B4.

[0033] In this embodiment, the driving direction of the actuator 6 is parallel to the beam Ba3. To produce variations in the interference fringes, the distance between the mirror B4 and the mirror A2 along the mirror image of the beam splitter 1 must change, and this change in distance originates from the movement of the mirror B4 along the direction of the beam Ba3. Since the mirror B4 follows the movement of the movable end of the pendulum mechanism 5, when the driving direction of the actuator 6 is parallel to the beam Ba3, under the action of this thrust, the pendulum mechanism 5 will inevitably produce a partial motion along the direction of the beam Ba3, and the mirror B4 will also follow suit and move along the direction of the beam Ba3.

[0034] In this embodiment, the pendulum mechanism 5 includes two pairs of identical bearing assemblies 51. Each bearing assembly 51 consists of a fixed bearing 511 located at the top and a movable bearing 513 located below and swinging around the fixed bearing 511, connected by a vertical rod 512. The fixed bearings 511 are at the same height, and the movable bearings 513 are connected by a horizontal rod 514. A reflector B4 is fixed to the side of the horizontal rod 514 away from the driver 6. The rotation axes of the bearings are parallel and not parallel to the beam Ba3. The movable bearings 513 are suspended below the fixed bearings 511 by the vertical rod 512 and can swing around the fixed bearings 511. The two fixed bearings 511 are fixed at the same height to the external mechanism, and the two movable bearings 513 are connected by a horizontal rod 514, allowing them to swing synchronously. This ensures that the horizontal rod 514 remains horizontal, and the reflector B4 is vertically fixed to the horizontal rod 514, thus maintaining a perpendicularity to the beam Ba3.

[0035] Example 2

[0036] As shown in Figure 4, the second embodiment of the pendulum Fourier transform spectrometer of the present invention is basically the same as that of embodiment 1, except that: in this embodiment, the pendulum mechanism 5 includes two pairs of bearing groups 51 with identical structures; the bearing group 51 includes a pair of fixed bearings 511 located above, and each fixed bearing 511 is connected by a vertical rod 512 to a movable bearing 513 located below and swinging around the corresponding fixed bearing 511; each fixed bearing 511 is distributed at the apex of a parallelogram on a horizontal plane, and the movable bearings 513 located on the same side in different bearing groups 51 are connected by a connecting rod 515, and the two connecting rods 515 are connected by a horizontal rod 514, on the side of the horizontal rod 514 away from the driver 6, a reflector B4 is fixed. The rotation axes of each bearing are parallel, and the rotation axes are not parallel to the beam Ba3. Embodiment 1 is a planar pendulum form, which has a weak ability to resist deflection perpendicular to the plane. By setting the bearing group 51 to form a three-dimensional pendulum, the ability to resist deflection perpendicular to the swing direction can be effectively enhanced, thereby further improving the stability of the structure.

[0037] Example 3

[0038] As shown in Figure 5, the third embodiment of the pendulum-type Fourier transform spectrometer of the present invention is basically the same as that of embodiment 1, except that: in this embodiment, the pendulum mechanism 5 includes four fixed bearings 511 distributed at the vertices of a parallelogram on a horizontal plane. Each fixed bearing 511 is hinged to a vertical rod 512 with a free end that can swing around it. The free ends of each vertical rod 512 are connected in sequence by connecting rods 515. Two connecting rods 515 arranged along the direction of the beam Ba3 are each hinged to a movable bearing 513. The two movable bearings 513 are connected by a crossbar 514. A reflector B4 is fixed on the side of the crossbar 514 away from the driver 6. The rotation axes of each bearing are parallel, but not parallel to the beam Ba3. Embodiment 1 is a planar pendulum, which has a weak ability to resist deflection perpendicular to the plane. By setting the bearing group 51 to form a three-dimensional pendulum, the ability to resist deflection perpendicular to the swing direction can be effectively enhanced, thereby further improving the stability of the structure.

[0039] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, should fall within the protection scope of the present invention.

Claims

1. A pendulum-type Fourier transform spectrometer, wherein a beam (a1) incident on a beam splitter (1) is split into two beams by reflection and transmission, wherein the beam A (a2) formed by reflection is reflected again by mirror A (2) and then passes through the beam splitter (1) into a detector (3); wherein the beam B (a3) ​​formed by transmission is reflected again by mirror B (4) and then reflected again by the beam splitter (1) into a detector (3) and interferes with the beam A (a2), characterized in that: The reflector B (4) is fixed to the movable end of the pendulum mechanism (5). The movable end of the pendulum mechanism (5) is periodically pushed by the driver (6) and carries the reflector B (4) which is always perpendicular to the beam direction B (a3) ​​to swing back and forth in the direction of approaching and moving away from the beam splitter (1). The pendulum mechanism (5) includes two pairs of bearing groups (51) with the same structure. The bearing group (51) consists of a fixed bearing (511) located above and a movable bearing (513) located below and swinging around the fixed bearing (511) connected by a vertical rod (512). Each fixed bearing (511) is located at the same height, and each movable bearing (513) is connected by a horizontal rod (514). The reflector B (4) is fixed on the side of the horizontal rod (514) away from the driver (6).

2. The pendulum-type Fourier transform spectrometer according to claim 1, characterized in that: The spectrometer includes a processing module (7), which is connected to the detector (3) and the driver (6) respectively.

3. The pendulum-type Fourier transform spectrometer according to claim 2, characterized in that: The driver (6) includes a movable shaft for periodically pushing the pendulum mechanism (5) and a grating ruler for acquiring real-time displacement information of the movable shaft.

4. The pendulum-type Fourier transform spectrometer according to claim 1, characterized in that: The contact surfaces of the driver (6) and the pendulum mechanism (5) are both fixed with magnetic components (8), and the magnetic components (8) on the driver (6) and the magnetic components (8) on the pendulum mechanism (5) repel each other.

5. The pendulum-type Fourier transform spectrometer according to claim 1, characterized in that: The contact surface between the driver (6) and the pendulum mechanism (5) is provided with an elastic element.

6. The pendulum-type Fourier transform spectrometer according to claim 1, characterized in that: The driving direction of the driver (6) is parallel to the beam B (a3).

7. The pendulum-type Fourier transform spectrometer according to any one of claims 1-6, characterized in that: The pendulum mechanism (5) includes two pairs of bearing groups (51) with the same structure; each bearing group (51) includes a pair of fixed bearings (511) located above, and each fixed bearing (511) is connected by a vertical rod (512) to a movable bearing (513) located below and swinging around the corresponding fixed bearing (511); each fixed bearing (511) is distributed at the apex of a parallelogram on a horizontal plane, and the movable bearings (513) located on the same side in different bearing groups (51) are connected by a connecting rod (515), and the two connecting rods (515) are connected by a horizontal rod (514), and a reflector B (4) is fixed on the side of the horizontal rod (514) away from the driver (6).

8. The pendulum-type Fourier transform spectrometer according to any one of claims 1-6, characterized in that: The pendulum mechanism (5) includes four fixed bearings (511) distributed at the apex of a parallelogram on a horizontal plane. Each fixed bearing (511) is hinged to a vertical rod (512) with a free end that can swing around it. The free ends of each vertical rod (512) are connected in sequence via connecting rods (515). Each of the two connecting rods (515) arranged along the direction of beam B (a3) ​​is hinged to a movable bearing (513). The two movable bearings (513) are connected by a crossbar (514). A reflector B (4) is fixed on the side of the crossbar (514) away from the driver (6).

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