Light beam adjusting assembly and atomic force microscope

Abstract

A light beam adjusting assembly and an atomic force microscope relate to the technical field of optical detection. The light beam adjusting assembly comprises a first plane mirror and a second plane mirror which are sequentially arranged along a main light path. Wherein an initial laser beam emitted by the laser source is emitted to the first plane mirror through the focusing lens, the first plane mirror adjusts the reflection direction so as to reflect the incident laser beam to the second plane mirror, and the second plane mirror adjusts the reflection direction so as to reflect the incident laser beam to the receiving plane. The optical axis of the focusing lens is perpendicular to the receiving plane, and the focus position of the laser beam on the receiving plane meets the preset requirement. The light beam adjusting assembly can reduce optical interference while ensuring small size, and ensures measurement precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical detection technology, in particular to a light beam adjusting assembly and an atomic force microscope. BACKGROUND

[0002] Atomic force microscope realizes nanoscale topography measurement by detecting the cantilever deflection caused by the interaction between the probe and the sample surface. In order to accurately capture the cantilever deflection, the laser beam is usually focused on the back of the cantilever, and the shape and position of the light spot reflected on the photodetector are recorded by the photodetector. However, in actual measurement, the cantilever needs to be tilted at a certain angle to avoid the probe holder from contacting or colliding with the sample. This tilt causes the optical axis of the focusing lens to deviate from the normal direction of the cantilever back, affecting the measurement accuracy. Therefore, it is necessary to adjust the direction of the laser beam and the focusing position to ensure that the optical axis of the focusing lens is perpendicular to the back of the cantilever and accurately focused.

[0003] In the prior art, a rotatable wedge prism group is usually used to adjust the direction of the light beam. By rotating two wedge prisms, the light beam can be continuously deflected within a conical range, and a third fixed prism is used to compensate for the tilt angle of the cantilever. However, the optical interfaces of the wedge prisms introduce additional reflection and interference, resulting in low measurement accuracy. Moreover, the structure is complex and bulky, making it difficult to integrate into a compact atomic force microscope probe. SUMMARY

[0004] The present application aims to provide a light beam adjusting assembly and an atomic force microscope which can reduce optical interference while ensuring a small size and improve the accuracy of light beam focusing.

[0005] Embodiments of the present application are implemented as follows:

[0006] In a first aspect, the present application provides a light beam adjusting assembly, comprising a first plane mirror and a second plane mirror arranged in sequence along a main light path; wherein an initial laser beam emitted by a laser source is emitted towards the first plane mirror through a focusing lens, the first plane mirror adjusts the reflection direction to reflect the incident laser beam to the second plane mirror, the second plane mirror adjusts the reflection direction to reflect the incident laser beam to a receiving plane, so that the optical axis of the focusing lens is perpendicular to the receiving plane, and the focal point position of the laser beam on the receiving plane meets the preset requirements.

[0007] In an optional embodiment, the plane of the first plane mirror forms a first included angle θ with the optical axis of the focusing lens, and the plane of the second plane mirror forms a second included angle θ with the optical axis of the laser beam between the reflected light paths of the first plane mirror, the second included angle θ satisfies Wherein α is the tilt angle between the receiving plane and the horizontal plane.

[0008] In an optional embodiment, the light beam adjusting assembly further comprises a focusing lens, which is located on the incident light path and the reflected light path of the first plane mirror, and the initial laser beam emitted by the laser source is focused on the receiving plane after sequentially passing through the focusing lens, the first plane mirror and the second plane mirror.

[0009] In an optional embodiment, the surface of the first plane mirror and / or the second plane mirror is coated with a high-reflection film layer.

[0010] In an optional embodiment, the high-reflection film layer is at least one of the following: an aluminum reflection layer, a silver reflection layer, and a gold reflection layer.

[0011] In a second aspect, the present application provides an atomic force microscope, comprising a cantilever, a laser emitter, a photodetector, and the light beam adjusting assembly according to any one of the preceding embodiments; the light beam adjusting assembly is used to adjust the initial laser beam emitted by the laser emitter, so that the optical axis of the focusing lens is perpendicular to the back surface of the cantilever, and the focal point position of the laser beam on the back surface of the cantilever meets the preset requirements; the photodetector is used to receive the reflected laser beam on the back surface of the cantilever, and obtain measurement results for the sample to be measured according to the reflected laser beam.

[0012] In an optional embodiment, the cantilever comprises a body and a probe arranged on the body.

[0013] In an optional embodiment, a first adjusting part is further included, which is in driving connection with the first plane mirror of the light beam adjusting assembly, and is used to adjust the reflection direction of the first plane mirror.

[0014] In an optional embodiment, a second adjusting part is further included, which is in driving connection with the second plane mirror of the light beam adjusting assembly, and is used to adjust the reflection direction of the second plane mirror.

[0015] In an optional embodiment, the first adjusting part comprises a first support seat, a first supporting plate, a first supporting ball and a first precision bolt, the first plane mirror is connected with the first supporting plate; the first supporting ball is located between the first supporting plate and the first support seat, and the first supporting plate and the first support seat are connected through a first tension spring; the first precision bolt penetrates the first supporting plate and abuts against the surface or the groove structure of the first support seat close to the first supporting plate, and the first supporting plate drives the first plane mirror to tilt along a first direction or a second direction around the ball center of the first supporting ball by rotating the first precision bolt.

[0016] In an optional embodiment, the second adjusting part comprises a second support base, a second supporting plate, a second supporting ball and a second precision bolt, the second plane mirror is connected with the second supporting plate, the second supporting ball is located between the second supporting plate and the second support base, and the second supporting plate and the second support base are connected through a second tension spring, the second precision bolt penetrates the second supporting plate and abuts against the surface or the groove structure of the second support base close to the second supporting plate, and the second supporting plate drives the second plane mirror to tilt around the ball center of the second supporting ball in the first direction or the second direction by rotating the second precision bolt.

[0017] The beneficial effects of the present application include at least one of the following:

[0018] The present application provides a light beam adjusting assembly, comprising a first plane mirror and a second plane mirror arranged in sequence along a main light path; wherein an initial laser beam emitted by a laser source is emitted towards the first plane mirror through a focusing lens, the first plane mirror adjusts the reflection direction to reflect the incident laser beam to the second plane mirror, and the second plane mirror adjusts the reflection direction to reflect the incident laser beam to a receiving plane, so that the optical axis of the focusing lens is perpendicular to the receiving plane, and the focal point position of the laser beam on the receiving plane meets the preset requirements. Compared with the prior art which changes the light path by using multiple wedge prism groups, the present application uses a single optical surface of the first plane mirror and the second plane mirror to realize light beam deflection, avoids the additional reflection and interference interference existing in the wedge prism refraction process, and can effectively ensure the measurement accuracy. In addition, the wedge prism group in the prior art needs to be matched by three prisms to realize light beam adjustment, and the structure is complex and large in size. The present application uses two plane mirrors arranged in sequence along the main light path, and can realize continuous deflection of the light beam direction by adjusting the angles of the two mirrors, which occupies small space and is convenient for compact integration with other elements, and meets the design requirements of miniaturized equipment. In summary, the above light beam adjusting assembly can reduce optical interference while ensuring small size, and ensure measurement accuracy.

[0019] This application also provides an atomic force microscope, including a cantilever, a laser emitter, a photodetector, and a beam adjustment assembly. The beam adjustment assembly is used to adjust the initial laser beam emitted by the laser emitter. The optical axis of the focusing lens is perpendicular to the receiving plane, and the focal position of the laser beam on the receiving plane meets preset requirements. The photodetector receives the laser beam reflected from the back of the cantilever and obtains the measurement results for the sample based on the reflected laser beam. This allows for adjustment of the angle of the laser beam incident on the back of the cantilever and the position of the beam focal point on the back of the cantilever when the optical axis of the focusing lens is not perpendicular to the back of the cantilever. This is achieved by adjusting the angle of the laser beam incident on the back of the cantilever and the position of the beam focal point on the back of the cantilever. Compared to existing technologies, this avoids the additional reflections and interference during the refraction process of the wedge prism, thus ensuring measurement accuracy. Furthermore, compared to the existing wedge prism assembly which requires the cooperation of three prisms to achieve beam adjustment, resulting in a complex structure and large size, the beam adjustment assembly of this application is smaller and does not require an additional optical path offset compensation structure, thus reducing the size of the atomic force microscope. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a conventional atomic force microscope laser beam adjustment structure provided in an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the structure of a single wedge prism provided in an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the structure of two wedge prisms provided in an embodiment of the present invention;

[0024] Figure 4 This is one of the structural schematic diagrams of the beam adjustment assembly provided in an embodiment of the present invention;

[0025] Figure 5 This is a second schematic diagram of the beam adjustment assembly provided in an embodiment of the present invention;

[0026] Figure 6 This is a schematic diagram of the structure of the first adjustment part provided in an embodiment of the present invention.

[0027] Icon: 16-piezoelectric wafer; 17-adjusting unit; 171-rotatable wedge prism assembly; 172-fixed wedge prism; 100-beam adjusting assembly; 110-first plane mirror; 120-second plane mirror; 130-focusing lens; 210-cantilever; 211-body; 212-probe; 220-first adjusting part; 221-first support seat; 222-first supporting plate; 223-first supporting ball; 224-first precision bolt; 225-first tension spring; 300-initial laser beam. DETAILED DESCRIPTION

[0028] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0029] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", and the like indicate the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present application is usually placed, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0030] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0031] Before introducing the present application, the working principle of an atomic force microscope (AFM) and the beam adjusting unit of the atomic force microscope (AFM) in the prior art will be briefly described.

[0032] Atomic force microscope (AFM) is widely used in precision engineering and micro-nanotechnology fields with its atomic level accuracy. The principle of AFM is based on the deflection of cantilever caused by the attractive or repulsive force between the probe tip and the measured surface. During the measurement process, the cantilever is usually slightly tilted to avoid the contact between the measured object surface and the cantilever holder, and to better measure the surface and side wall of the measured object. However, the tilted state of the cantilever will cause the optical axis of the focusing lens to be no longer perpendicular to the back of the cantilever. To solve this problem, the existing technology uses a wedge prism to adjust the direction and focusing position of the focused laser beam. The specific working process is as follows.

[0033] Please refer to Figure 1 The atomic force microscope (AFM) can include a cantilever 210, a piezoelectric stack 16, an adjusting unit 17, and a focusing lens 130.

[0034] The cantilever 210 includes a body 211 and a probe 212 arranged on the body 211. During the measurement process, the probe 212 can directly interact with the surface of the measured sample, and convert the atomic force between the probe 212 and the measured sample into the bending of the cantilever 210. The piezoelectric stack 16 can drive the measured sample to move in the vertical direction to generate vibration in the vertical direction. The adjusting unit 17 is used to adjust the angle between the optical axis of the focusing lens 130 and the back of the cantilever 210, and the focusing position of the laser beam on the back of the cantilever 210. In some embodiments, the adjusting unit 17 can include a rotatable wedge prism assembly 171 and a fixed wedge prism 172.

[0035] In the implementation of the prior art, the adjustment is mainly performed by the rotatable wedge prism assembly 171, and the specific adjustment principle is as follows. The rotatable wedge prism assembly 171, also known as Risley prism, is composed of two rotatable wedge prisms with the same geometric shape. By rotating the pair of wedge prisms, the laser beam can be deflected within the wedge angle for deflection measurement. The two wedge prisms of the rotatable wedge prism assembly 171 can be rotated relative to each other or together, thereby adjusting the deflection direction of the laser beam. Figure 2 The single wedge prism structure is shown. The single wedge prism can produce a beam adjustment deflection angle θ D Depending on its refractive index and wedge angle θ c . Figure 3 The rotatable wedge prism group composed of two wedge prisms is shown. By adjusting the relative rotation angle between the two wedge prisms, the direction of the outgoing beam can be continuously changed within a certain conical range. The maximum deflection angle that can be achieved by the wedge prism combination is four times that of the single wedge prism, i.e. 4θ D .

[0036] However, in the existing way of adjusting the direction and focusing position of the focused laser beam by using the wedge prism, the wedge prism will cause additional reflection and interference, resulting in measurement error. Therefore, the existing adjustment structure has the problem of causing large measurement error of the measurement system. In addition, in the existing implementation, in order to match the tilt angle of the cantilever (8° for the AFM system), an additional third wedge prism is needed. Therefore, the existing implementation has the problem of large volume.

[0037] Therefore, the present application provides a beam adjustment assembly which can be applied to an atomic force microscope to adjust the angle between the optical axis of a focusing lens and the back of a cantilever and the focusing position of a laser beam on the back of the cantilever. Compared with the prior art, the beam adjustment assembly can avoid the additional reflection and interference existing in the refraction process of the wedge prism, effectively ensure the measurement accuracy, and does not need to introduce an additional optical path offset compensation structure in the implementation process, thereby reducing the volume of the atomic force microscope.

[0038] Please refer to Figure 4 The present embodiment provides a beam adjustment assembly which comprises a first plane mirror 110 and a second plane mirror 120 arranged in sequence along a main light path. The initial laser beam 300 emitted by a laser source is emitted towards the first plane mirror 110 through a focusing lens 130, the first plane mirror 110 adjusts the reflection direction to reflect the incident laser beam to the second plane mirror 120, the second plane mirror 120 adjusts the reflection direction to reflect the incident laser beam to a receiving plane, so that the optical axis of the focusing lens 130 is perpendicular to the receiving plane, and the focal point position of the laser beam on the receiving plane meets the preset requirements.

[0039] Specifically, the beam adjustment assembly 100 is designed to solve the problem of additional reflection and interference existing in the existing wedge prism. Optionally, the first plane mirror 110 and the second plane mirror 120 are arranged in front and back along the main light path of the laser beam transmission. The first plane mirror 110 and the second plane mirror 120 can be angle-adjusted by an adjusting part to adjust the pitch angle and yaw angle of the first plane mirror 110 and the second plane mirror 120, so as to change the reflection direction of the laser beam. Compared with the existing way of changing the light path by using multiple wedge prism groups, the first plane mirror 110 and the second plane mirror 120 in the beam adjustment assembly 100 of the present application realize beam deflection by a single optical surface, avoiding the additional reflection and interference existing in the refraction process of the wedge prism, and effectively ensuring the measurement accuracy.

[0040] And, the application adopts two plane mirrors which are arranged along the main light path in turn, and the angle of the two plane mirrors is adjusted to realize the adjustment of the angle of the laser beam incident to the back of the cantilever, and the focusing lens can realize the adjustment of the position of the focal point of the laser beam on the back of the cantilever, so that the space occupied is small, the light beam adjusting assembly can be integrated with other elements in the atomic force microscope, and the design requirement of miniaturized equipment is met.

[0041] The laser source as the emission end of the laser beam can be a semiconductor laser, a gas laser or the like, and the initial laser beam 300 emitted by the laser source can become a collimated light beam with a specific spot size after being processed by a preset optical system. The initial laser beam 300 is refracted by the focusing lens and is incident to the surface of the first plane mirror 110 along the direction of the main light path.

[0042] Alternatively, the first plane mirror 110 and the second plane mirror 120 can be arranged in an inclined manner. The main function of the first plane mirror 110 is to preliminarily adjust the direction of the initial laser beam 300. When the initial laser beam 300 is incident to the surface of the first plane mirror 110, according to the law of reflection, the reflection direction of the laser beam can be changed by adjusting the angle of the first plane mirror 110, so that the reflected laser beam can be accurately projected on the second plane mirror 120. The adjustment process can be realized by manually adjusting a knob or an automatically controlled driving device.

[0043] The main function of the second plane mirror 120 is to receive the laser beam reflected by the first plane mirror 110 and adjust it again to reflect the incident laser beam to a receiving plane, so that the optical axis of the focusing lens is perpendicular to the receiving plane, and the focal point position of the laser beam on the receiving plane meets the preset requirement, thereby meeting the preset measurement requirement and ensuring the measurement accuracy. For example, in the atomic force microscope, by applying the light beam adjusting assembly provided in the embodiments of the application, the optical axis of the focusing lens is adjusted to be perpendicular to the receiving plane, and the focal point position of the laser beam on the receiving plane meets the preset requirement (for example, the focal point position is a specific area of the receiving plane), so that the photodetector can accurately capture the slight deflection signal of the cantilever 210, reduce the measurement error, and effectively ensure the measurement accuracy.

[0044] It can be understood that, if the light beam adjusting assembly is applied to the atomic force microscope, the above-mentioned receiving plane can be the back of the cantilever in the atomic force microscope. In addition, it should be noted that, in some embodiments, when the light beam adjusting assembly is applied to the atomic force microscope, the size of the focal point of the laser beam on the receiving plane can also be adjusted to meet the preset requirement (for example, the preset focal point area), that is, the size and / or position of the focal point of the laser beam on the receiving plane meet the preset requirement, which is not limited herein and can be flexibly set according to the actual application scenario.

[0045] Of course, it should be noted that the application scenario of the light beam adjusting assembly is not limited to atomic force microscopes. According to the actual application scenario, the light beam adjusting assembly can also be applied to other structures that have the same adjustment requirements as the adjustment unit in the atomic force microscope to achieve the corresponding adjustment function.

[0046] It should be noted that the specific structure and size of the first plane mirror 110 and the second plane mirror 120 are not limited in the present application, as long as the first plane mirror 110 and the second plane mirror can reflect the laser beam and meet the requirements of the preset angle and position range adjustment, and do not block the optical path. For example, in order to minimize the volume of the light beam adjusting assembly 100 and not to block the optical path during adjustment, the first plane mirror 110 and the second plane mirror 120 can be elliptical plane mirrors.

[0047] As shown in Figure 5 In an embodiment of the present application, the plane of the first plane mirror 110 forms a first included angle θ with the optical axis of the focusing lens, and the plane of the second plane mirror 120 forms a second included angle θ with the optical axis of the laser beam between the reflected light paths of the first plane mirror. The second included angle θ satisfies Where α is the inclination angle between the receiving plane and the horizontal plane.

[0048] Alternatively, in some embodiments, considering the deviation of the mirror edge, the distance between the incident light beam and the reflected light beam in the focusing lens, the focal length of the focusing lens, and other factors, in order to avoid collision and obstruction, the first included angle θ1 can be set to 45°, and then the second included angle θ2 can be determined according to the above formula .

[0049] Where, if the inclination angle α between the receiving plane and the horizontal plane is 8°, then the second included angle θ2 is calculated to be 49°. Of course, it should be noted that the setting of the first included angle, the second included angle and the inclination angle is not limited to this, and can be flexibly set according to the actual application scenario.

[0050] Alternatively, in order to reduce the energy loss of the laser beam during reflection and improve the optical performance of the light beam adjusting assembly 100, the surface of the first plane mirror 110 and / or the second plane mirror 120 is coated with a high reflection film layer. Alternatively, the high reflection film layer can be an aluminum reflection layer. Of course, in addition to the aluminum reflection layer, it can also be a silver reflection layer, a gold reflection layer, and other metal reflection layers, which are not limited here. It should be noted that the high reflection film layer refers to a functional thin film that enhances the surface reflectivity through optical design.

[0051] In an implementation form of the present application, in order to further optimize the transmission performance of the laser beam, the beam adjusting assembly 100 further comprises a focusing lens 130, which is located on the incident light path and the reflected light path of the first plane mirror 110, and the initial laser beam 300 emitted by the laser source is focused on the receiving plane after passing through the focusing lens 130, the first plane mirror 110 and the second plane mirror 120 in sequence. Wherein, the focusing lens 130 uses the refraction principle to focus the initial laser beam 300 to a smaller spot size by converging different rays in the laser beam, and improves the energy concentration of the beam; the focused laser beam is emitted in an optimized form and accurately projected onto the surface of the first plane mirror 110, providing a high-quality beam basis for subsequent reflection direction adjustment and ensuring that the photodetector can sensitively capture the micro deformation of the cantilever.

[0052] Optionally, the maximum allowable inclination between the first plane mirror 110 and the horizontal plane can be calculated according to the distance between the incident light beam and the exit light beam in the focusing lens 130 and the length size of the first plane mirror 110. The specific calculation can refer to the following formula.

[0053] In some embodiments, as shown in Figure 5 the distance between the incident light beam and the exit light beam in the focusing lens 130 is d (mm), the size of the first plane mirror 110 is a (mm) x b (mm), wherein a represents the length of the first plane mirror 110 and b represents the width of the first plane mirror 110, then the maximum allowable inclination between the first plane mirror 110 and the horizontal plane can be calculated according to the following formula Optionally, the thickness of the first plane mirror 110 can be 2mm, but is not limited thereto.

[0054] For example, taking d = 4mm, a = 14mm and b = 10mm as an example, the maximum allowable inclination between the first plane mirror 110 and the horizontal plane is 73° In addition, it should be noted that in some embodiments, the first plane mirror 110 and the second plane mirror 120 can be the same or different, which is not limited herein.

[0055] In summary, it can be seen that the above-mentioned beam adjusting assembly 100 can avoid the additional reflection and interference interference existing in the refraction process of the wedge prism, can effectively ensure the measurement accuracy, and in addition, occupies small space, is convenient for compact integration with other elements, and meets the design requirements of miniaturized equipment.

[0056] The application further provides an atomic force microscope, comprising a cantilever 210, a laser emitter, a photodetector and a light beam adjusting assembly 100; wherein the light beam adjusting assembly is used for adjusting an initial laser light beam emitted by the laser emitter, so that the optical axis of a focusing lens is perpendicular to the back surface of the cantilever, and the focal point of the laser light beam on the back surface meets preset requirements; the photodetector is used for receiving the laser light beam reflected by the back surface of the cantilever, and obtaining a measurement result for the sample to be measured according to the reflected laser light beam.

[0057] Optionally, the photodetector can include the aforementioned position sensitive detector, an interferometric measurement module, etc., and is not limited herein, and the specific measurement principle can be referred to the aforementioned related content, which will not be described herein again. In some embodiments, the sample to be measured can be metal, alloy, semiconductor chip, ceramic, hard polymer, mineral, biological material, etc., and is not limited herein, and can be different according to specific application scenarios.

[0058] Specifically, the cantilever 210 is usually made of silicon or silicon nitride material, as shown in FIG. 1, which includes a body 211 and a probe 212 arranged on the body 211. Figure 4

[0059] When the cantilever 210 works, the interaction force between the probe 212 and the sample surface will cause a slight deformation of the cantilever 210, and the slight deformation can reflect the topographic information of the sample surface; optionally, the laser emitter can be a semiconductor laser or a gas laser.

[0060] Specifically, in the working process, the laser light beam is usually focused on the back surface of the cantilever 210, and the photodetector is used for receiving the laser light beam reflected by the back surface of the cantilever 210, and obtaining a measurement result for the sample to be measured according to the reflected laser light beam. Optionally, the photodetector can include a position sensitive detector (PSD), which can convert the optical signal into an electrical signal for measuring the position change of the reflected laser light beam on the PSD. Of course, it can be understood that the measurement result for the sample to be measured according to the reflected laser light beam can also be realized in combination with a corresponding circuit processing module, which is not limited herein.

[0061] In addition, in order to avoid the cantilever holder from contacting or colliding with the sample to be measured, the body 211 can have a preset included angle a with the horizontal plane.

[0062] ​The initial laser beam 300 emitted by the laser emitter is refracted by the focusing lens 130 and then enters the first plane mirror 110 and the second plane mirror 120 in the beam adjusting assembly 100 in sequence. By adjusting the position of the focusing lens 130 along the optical axis direction, the laser beam can be focused on the back surface of the cantilever 210. When the optical axis of the focusing lens 130 is not perpendicular to the back surface of the cantilever 210, by adjusting the angles of the two adjustable plane mirrors and the position of the focusing lens 130 along the optical axis direction, the adjustment of the angle between the optical axis of the focusing lens 130 and the back surface of the cantilever and the adjustment of the position of the focal point on the back surface can be realized, so that the laser beam can be focused on the back surface of the cantilever. Compared with the prior art, the additional reflection and interference interference existing in the refraction process of the wedge prism can be avoided, thereby ensuring the accuracy of the measurement. Moreover, compared with the implementation manner in the prior art, the volume of the beam adjusting assembly of the present application is smaller, and no additional optical path offset compensation structure is required, thereby reducing the volume of the atomic force microscope.

[0063] The specific structure and beneficial effects of the beam adjusting assembly have been described in detail above, and will not be repeated here.

[0064] Optionally, the atomic force microscope further comprises a first adjusting part 220 connected with the first plane mirror 110 of the beam adjusting assembly 100, for adjusting the reflection direction of the first plane mirror 110.

[0065] Specifically, the first adjusting part 220 is used to realize accurate control of the beam direction, and is connected with the first plane mirror 110 in the beam adjusting assembly 100 to adjust the reflection direction of the first plane mirror 110.

[0066] In some embodiments, the atomic force microscope can further comprise a second adjusting part connected with the second plane mirror 120 of the beam adjusting assembly 100 to adjust the reflection direction of the second plane mirror 120.

[0067] In the adjustment process of the first plane mirror 110 and the second plane mirror 120, the first plane mirror 110 can be adjusted by the first adjusting part 220, and / or the second plane mirror 120 can be adjusted by the second adjusting part, which is not limited here, and can be flexibly selected according to the actual application scenario.

[0068] For example, as shown in FIG. 4, the atomic force microscope can further comprise a first adjusting part 220 connected with the first plane mirror 110 of the beam adjusting assembly 100, for adjusting the reflection direction of the first plane mirror 110. Figure 6As shown, the first adjusting part 220 comprises a first support base 221, a first supporting plate 222, a first supporting ball 223 and a first precision bolt 224, the first plane mirror 110 is connected with the first supporting plate 222; the first supporting ball 223 is located between the first supporting plate 222 and the first support base 221, and the first supporting plate 222 and the first support base 221 are connected through the first tension spring 225; the first precision bolt 224 is arranged through the first supporting plate 222 and abuts against the surface or the groove structure of the first support base 221 close to the first supporting plate 222, and the first precision bolt 224 can drive the first supporting plate 222 to drive the first plane mirror 110 to tilt along the first direction or the second direction around the first supporting ball 223.

[0069] Optionally, the first direction and the second direction can be determined according to a preset coordinate system, wherein the preset coordinate system can be composed of three mutually perpendicular coordinate axes (X axis, Y axis and Z axis), and a plane composed of the Y axis and the Z axis can be parallel to a horizontal plane. In some embodiments, the first direction can be a direction indicated by the X axis, and the second direction can be a direction indicated by the Y axis.

[0070] Specifically, as shown in the first adjusting part 220, Figure 6 The first support base 221 provides a stable mounting base for the entire first adjusting part 220, and optionally, the first support base 221 can be made of a material with a low thermal expansion coefficient to avoid deformation of the first support base 221 due to temperature changes, thereby affecting the measurement results of the measurement system.

[0071] The first supporting ball 223 serves as a supporting point between the first supporting plate 222 and the first support base 221, and is preferably made of a ceramic or hard alloy material with high hardness and wear resistance. The first supporting ball 223 provides a flexible rotating support point for the supporting plate, and functions to provide a low-friction, high-degree-of-freedom rotating support point for the supporting plate, so that the first supporting plate 222 can be tilted and adjusted around the X axis and the Y axis around the first supporting ball 223, thereby effectively reducing the adjustment errors caused by gaps and wear in traditional hinged structures. In some embodiments, the first supporting plate 222 and the first support base 221 can be respectively provided with grooves capable of accommodating the first supporting ball 223.

[0072] Optionally, the first supporting plate 222 and the first support base 221 can be connected through the first tension spring 225, and the first tension spring 225 can make the first supporting plate 222 tightly fit on the surface of the first supporting ball 223 by applying a preset tension, thereby avoiding displacement caused by vibration or external force interference. In some embodiments, the first supporting plate 222 and the first support base 221 can have an L-shaped structure. Of course, the specific structure is not limited to this, and can be flexibly set according to the actual application scenario.

[0073] Further, the first supporting plate 222 is used to support the first plane mirror 110, and the first plane mirror 110 can be attached to the first supporting plate 222, so that the first plane mirror 110 can move synchronously with the first supporting plate 222 during adjustment, and the direction of the reflected light beam can be adjusted accurately.

[0074] In addition, it should be noted that the number of the first precision bolts 224 in the first adjusting part 220 can be one or more, and when the number of the first precision bolts 224 is more than one, the first precision bolts 224 can be arranged on the first supporting plate 222 and abut against the surface or the groove structure of the first supporting seat 221 close to the first supporting plate 222.

[0075] During adjustment, the first precision bolts 224 can be rotated clockwise or counterclockwise, and the rotation of the first precision bolts 224 can drive the first supporting plate 222 to tilt. It can be understood that when the first plane mirror 110 needs to be adjusted around the X-axis, the corresponding first precision bolt 224 (one of them) can be adjusted, and due to the fulcrum effect of the first supporting ball 223, the first supporting plate 222 tilts around the X-axis, and the first plane mirror 110 tilts synchronously, so that the angle of the reflected light beam in this direction can be adjusted.

[0076] When the first plane mirror 110 needs to be adjusted around the Y-axis, the operation process is similar to that of the X-axis, and the two first precision bolts 224 are rotated synchronously to adjust the first plane mirror 110 to tilt around the Y-axis.

[0077] Based on the above, it can be seen that through the adjustment mechanism that can be adjusted independently along the X-axis and the Y-axis, the first plane mirror 110 can be adjusted accurately in two dimensions, and combined with the coordinated adjustment of the second plane mirror 120 in the light beam adjusting assembly 100, the deviation of the incident angle of the light beam caused by the tilt of the cantilever 210 in the atomic force microscope can be effectively compensated, so that the optical axis of the focusing lens 130 is perpendicular to the back surface of the cantilever, and the measurement accuracy of the atomic force microscope is improved.

[0078] Referring to the above description of the first adjusting part, in some embodiments, the second adjusting part can include a second supporting seat, a second supporting plate, a second supporting ball and a second precision bolt, the second plane mirror is connected to the second supporting plate; the second supporting ball is located between the second supporting plate and the second supporting seat, and the second supporting plate and the second supporting seat are connected by a second tension spring; the second precision bolt passes through the second supporting plate and abuts against the surface or the groove structure of the second supporting seat close to the second supporting plate, and the second precision bolt can drive the second supporting plate and the second plane mirror to tilt around the second supporting ball along a first direction or a second direction by rotating the second precision bolt.

[0079] When the second plane mirror needs to be adjusted around the X-axis direction, the corresponding second precision screw can be adjusted. At this time, due to the fulcrum effect of the second supporting ball, the second supporting plate tilts around the X-axis, thereby driving the second plane mirror to tilt synchronously, thereby realizing the adjustment of the beam reflection angle in this direction.

[0080] When the second plane mirror needs to be adjusted around the Y-axis direction, the operation process is similar to that of the X-axis. By synchronously rotating the two second precision screws, the second plane mirror is adjusted around the Y-axis direction.

[0081] It should be noted that other contents of the second adjusting part can be referred to the description of the first adjusting part described above, and will not be repeated here.

[0082] By using the adjusting mechanism that can be independently adjusted around the X-axis and the Y-axis, the second plane mirror 120 can realize accurate angle fine adjustment in two dimensions, and in combination with the coordinated adjustment of the first plane mirror in the beam adjusting assembly, the deviation of the beam incidence angle caused by the cantilever 210 of the atomic force microscope can be effectively compensated, and the optical axis of the focusing lens 130 is perpendicular to the back surface of the cantilever, thereby improving the measurement accuracy of the atomic force microscope.

[0083] It should be noted that according to the actual application scene, a first adjusting part for adjusting the position of the focusing lens can also be provided. The position of the focusing lens along the optical axis is adjusted by the first adjusting part, thereby adjusting the focal point position of the laser beam on the back surface of the cantilever. Of course, the application does not limit the setting mode of the first adjusting part here, for example, the adjusting part setting of the plane mirror can be referred to.

[0084] In some embodiments, when the first plane mirror 110 is fixed at a certain angle, the adjustable angle of the second plane mirror 120 can be ±3°, the focal point on the back surface of the cantilever can be adjusted within a circular range with a diameter of about 250-290 μm, and the optical axis of the focusing lens can be perpendicular to the back surface of the cantilever with a preset included angle, thereby ensuring the accuracy of the measurement result.

[0085] In summary, by using the embodiments of the application, the adjustment of the reflection angles of the first plane mirror 110 and the second plane mirror 120 can be realized by adjusting the precision screw, which has the characteristics of simple design, small size and convenient maintenance, and can avoid the problems of large overall size of the atomic force microscope and difficult maintenance of the motor.

[0086] The above merely describes optional embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall fall within the protection scope of the present application.

[0087] In addition, it should be noted that various specific technical features described in the foregoing embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, various possible combinations are not described again in the present application.

Claims

1. A beam conditioning assembly, comprising: The light beam adjusting assembly comprises a first plane mirror and a second plane mirror arranged in sequence along a main light path; wherein an initial laser beam emitted by a laser source is emitted towards the first plane mirror through a focusing lens, the first plane mirror adjusts a reflection direction to reflect the incident laser beam to the second plane mirror, the second plane mirror adjusts the reflection direction to reflect the incident laser beam to a receiving plane, the optical axis of the focusing lens is perpendicular to the receiving plane, and the focal point position of the laser beam on the receiving plane meets preset requirements.

2. The beam conditioning assembly of claim 1, wherein, The plane of the first plane mirror and the optical axis of the focusing lens form a first included angle θ, the plane of the second plane mirror and the optical axis of the laser beam form a second included angle θ between the reflected light paths of the first plane mirror, and the second included angle θ satisfies wherein a is the angle of inclination between the receiving plane and the horizontal plane.

3. The beam conditioning assembly of claim 1, wherein, The light beam adjusting assembly further comprises a focusing lens located on the incident light path and the reflection light path of the first plane mirror, and the initial laser beam emitted by the laser source is focused on the receiving plane in sequence through the focusing lens, the first plane mirror and the second plane mirror.

4. The beam conditioning assembly of claim 1, wherein, The surface of the first plane mirror and / or the second plane mirror is coated with a high reflection film layer.

5. The beam conditioning assembly of claim 4, wherein, The high reflection film layer is at least one of an aluminum reflection layer, a silver reflection layer and a gold reflection layer.

6. An atomic force microscope characterized by The light beam adjusting assembly is used for adjusting the initial laser beam emitted by the laser emitter, so that the optical axis of the focusing lens is perpendicular to the back surface of the cantilever, the focal point position of the laser beam on the back surface of the cantilever meets preset requirements, and the photodetector is used for receiving the reflected laser beam on the back surface of the cantilever and obtaining measurement results for the sample to be measured according to the reflected laser beam.

7. The atomic force microscope of claim 6, wherein, The cantilever comprises a body and a probe arranged on the body.

8. The atomic force microscope of claim 6, wherein, The first adjusting part is drivingly connected with the first plane mirror of the light beam adjusting assembly and is used for adjusting the reflection direction of the first plane mirror.

9. The atomic force microscope of claim 6, wherein, The second adjusting part is drivingly connected with the second plane mirror of the light beam adjusting assembly and is used for adjusting the reflection direction of the second plane mirror.

10. The atomic force microscope of claim 8, wherein, The first adjusting part comprises a first support seat, a first supporting plate, a first supporting ball and a first precision bolt, the first plane mirror is connected with the first supporting plate, the first supporting ball is located between the first supporting plate and the first support seat, the first supporting plate and the first support seat are connected through a first tension spring, the first precision bolt penetrates the first supporting plate and abuts against the surface or the groove structure of the first support seat close to the first supporting plate, and the first supporting plate drives the first plane mirror to tilt around the ball center of the first supporting ball in a first direction or a second direction by rotating the first precision bolt.

11. The atomic force microscope of claim 9, wherein, The second adjusting part comprises a second support base, a second supporting plate, a second supporting ball and a second precision bolt, the second plane mirror is connected with the second supporting plate; the second supporting ball is located between the second supporting plate and the second support base, and the second supporting plate and the second support base are connected through a second tension spring; the second precision bolt passes through the second supporting plate and abuts against the surface or the groove structure close to the second supporting plate in the second support base, and the second supporting plate drives the second plane mirror to tilt along the first direction or the second direction around the ball center of the second supporting ball by rotating the second precision bolt.

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