Probe scanning monitoring device

Abstract

This invention discloses a probe scanning monitoring device, comprising the following optical components: a laser, an adjustable aperture, a polarizing beam splitter, a quarter-wave plate I, a four-quadrant detector, a cemented lens, a reflecting mirror I, a thin-film beam splitter I, a camera, an illumination source, a quarter-wave plate II, a reflecting mirror II, a lens barrel, a thin-film beam splitter II, and a microscope objective; all optical components are mounted on the lens barrel structure. This invention provides an optical system for precision tracking, applicable to AFM systems; it increases the existing scanning travel by 3 times to 300 μm; the overall device enables fully automated focusing, detector alignment, rapid probe advance, and scanning.

Description

Technical Field

[0001] This utility model relates to the technical field of optical measurement devices, specifically a probe scanning monitoring device. Background Technology

[0002] In precision measurement, using lasers as the working light source is a very effective and convenient method. However, how to track and collect data after the laser is emitted is a key difference that fundamentally distinguishes various measurement devices. Furthermore, the accuracy of laser tracking and monitoring also determines the overall accuracy of the measurement equipment.

[0003] In precision measurement equipment, AFM (atomic force microscope) is an ultra-precision measuring device that can measure down to tens of micrometers (pm). The internal optical device of the scanning head, one of its core components, is also the part that most directly generates and monitors the measurement accuracy. For the internal system of this scanning head, how to improve the scanning speed and scanning range is a key technical problem to be solved. Utility Model Content

[0004] The purpose of this invention is to propose a probe scanning monitoring device. This device accurately focuses the emitted working laser onto the surface of the probe to be measured through an optical path system. After being reflected by the probe, the laser is received by a detector. Through a precision piezoelectric beam splitter, the laser can be tracked at the probe position, and a large range of measurements can be achieved.

[0005] The technical solution adopted is as follows: A probe scanning monitoring device includes the following optical components: a laser, an adjustable aperture, a polarizing beam splitter, a quarter-wave plate I, a four-quadrant detector, a cemented lens, a reflecting mirror I, a thin-film beam splitter I, a camera, an illumination source, a quarter-wave plate II, a reflecting mirror II, a tube lens, a thin-film beam splitter II, and a microscope objective; all optical components are mounted on the tube structure. The laser beam passes sequentially through an adjustable aperture, a polarizing beam splitter, a quarter-wave plate I, a reflecting mirror I, a thin-film beam splitter I, and a microscope objective, finally illuminating the probe. The laser beam reflected from the probe passes sequentially through the microscope objective, thin-film beam splitter I, a reflecting mirror I, a quarter-wave plate I, and a cemented lens, finally being received by a four-quadrant detector, forming the monitoring optical path. The camera beam passes sequentially through a quarter-wave plate II, a reflecting mirror II, a telescope lens, a thin-film beam splitter II, a thin-film beam splitter I, and a microscope objective, finally illuminating the probe. The camera beam is reflected from the probe surface, and the reflected beam passes sequentially through the microscope objective, thin-film beam splitter I, thin-film beam splitter II, a telescope lens, a reflecting mirror II, and a quarter-wave plate II, finally being received by the camera, forming the monitoring optical path. Both thin-film beam splitter I and thin-film beam splitter II are mounted on a piezoelectric optical adjustment frame, which is fixed to the lens barrel structure. The optical axes of the four-quadrant detector and the cemented lens are collinear and aligned with the center of the reflecting surface of the polarizing beam splitter. The microscope objective is equipped with a displacement stage that drives the microscope objective to move up and down, and a piezoelectric ceramic is mounted on the microscope objective to drive the microscope objective to move in the Z direction.

[0006] In a further preferred embodiment of the present invention, the laser is a semiconductor laser or a fiber laser.

[0007] In a further optimization of the technical solution of this utility model, both the thin-film beam splitter I and the thin-film beam splitter II are driven by the piezoelectric optical adjustment frame to perform pitch adjustment, with an adjustment accuracy of 0.5 μrad and an adjustment range of ±1.5 mrad.

[0008] Further optimization of the technical solution of this utility model: the coaxiality of the laser, adjustable aperture, polarizing beam splitter, quarter-wave plate I, reflector I and thin-film beam splitter I in the monitoring optical path is <0.5′.

[0009] In a further preferred embodiment of the present invention, the coaxiality of the thin-film beam splitter I, the microscope objective, and the probe in the monitoring optical path is <0.5′, and the vertical distance between the microscope objective and the probe is 20mm±0.1mm.

[0010] In a further optimization of the technical solution of this utility model, both reflector I and reflector II are adjustable pitch reflectors with an adjustable pitch angle of ±2°.

[0011] In a further optimization of the technical solution of this utility model, both the quarter wave plate I and the quarter wave plate II can rotate around their own central axis.

[0012] In a further preferred embodiment of the present invention, the laser is inserted into the lens barrel structure with an interference fit and fixed with a set screw.

[0013] In a further optimization of the technical solution of this utility model, the adjustable aperture and the polarizing beam splitter are fixed to the lens barrel structure by means of a fixed lens mount pressure ring or adhesive application.

[0014] A further optimization of the technical solution of this utility model is that the displacement accuracy of the displacement stage on the microscope objective is 1μm and the stroke is >5mm.

[0015] In a further preferred embodiment of the present invention, the probe is located on the focal plane of the microscope objective, the probe is mounted on the microscope tube structure via a probe holder, and an XY displacement stage is provided on the probe.

[0016] The advantages of this utility model compared with the prior art are: 1. The probe scanning monitoring device of this utility model uses a precision piezoelectric beam splitter with a high-magnification microscope objective system. The range of the entire optical tracking system can reach 300μm, and its travel measurement range exceeds that of the prior art by 100μm.

[0017] 2. The probe scanning monitoring device of this utility model can effectively realize fully automatic monitoring and scanning functions by adding an electric displacement stage to the detector and the microscope objective.

[0018] 3. The probe scanning monitoring device of this utility model adopts a coaxial vision monitoring system. The microscope objective is both a laser working objective and a camera microscope objective, which improves the visual observation capability. At the same time, due to the short depth of focus, it can quickly insert needles and is an AI visual recognition function device. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the probe scanning monitoring device of this utility model; Wherein: 1-Laser, 2-Adjustable aperture, 3-Polarizing beam splitter, 4-1 / 4 wave plate I, 5-Four-quadrant detector, 6-Cemented lens, 7-Reflector I, 8-Thin-film beam splitter I, 9-Reflector II, 10-Tube lens, 11-Camera, 12-Illumination source, 13-Microscopic objective, 14-Probe, 15-Thin-film beam splitter II, 16-1 / 4 wave plate II. Detailed Implementation

[0020] The technical solution of this utility model will be described in detail below, but the protection scope of this utility model is not limited to the embodiments described.

[0021] To make the content of this utility model clearer and easier to understand, the following description is in conjunction with the appendix. Figure 1 The specific implementation methods will be further described below.

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0023] like Figure 1 As shown, this embodiment is a probe scanning monitoring device. The principle of this device is as follows: the emitted working laser is precisely focused on the surface of the measurement probe through the optical path system, reflected by the probe, and then received by the detector. Through the precision reflector device, the laser can be tracked at the probe position and a large range of measurement can be achieved.

[0024] The monitoring optical path of the device in this embodiment is mainly described as follows: the monitoring light emitted from the laser passes through a series of optical elements and finally enters the probe surface. Then, it is reflected back to the optical path system by the probe and finally received by the detector.

[0025] The device in this embodiment includes the following optical components: laser 1, adjustable aperture 2, polarizing beam splitter 3, quarter wave plate I4, quadrant detector 5, cemented lens 6, reflector I 7, thin film beam splitter I 8, camera 11, illumination source 12, quarter wave plate II 16, reflector II 9, tube lens 10, thin film beam splitter II 15, and microscope objective 13.

[0026] All optical elements are mounted on the lens barrel structure; the illumination source 12 provides illumination for this device. The lens barrel structure is a type of structure known to those skilled in the art for mounting optical elements.

[0027] The device in this embodiment includes a monitoring optical path and a surveillance optical path. The monitoring optical path emits monitoring light from a laser, passes through a series of optical elements, and finally strikes the probe surface. The light is then reflected back to the optical path system by the probe and finally received by a four-quadrant detector. The surveillance optical path emits monitoring light from a camera, passes through a series of optical elements, and finally strikes the probe surface. The light is then reflected back to the optical path system by the probe and finally received by the camera; both paths are used to monitor whether the probe is on the focal plane of the microscope objective 13.

[0028] In this embodiment, the laser 1 is a semiconductor laser or a fiber laser, with no power limit but less than 50mW. The wavelength can be selected as 532nm, 633nm, 808nm or other visible or near-infrared bands. After collimation, the light is emitted, and the beam size is within 7mm. The light emission mode can be flat-top light or single-mode Gaussian light.

[0029] In this embodiment, the laser 1 is interference-fitted into the lens barrel structure and fixed with a set screw. The adjustable aperture 2 and the polarizing beam splitter 3 are fixed to the lens barrel structure using a fixed lens mount pressure ring or adhesive. Both the quarter-wave plate I 4 and the quarter-wave plate II 16 can rotate around their own central axis. The optical axes of the quadrant detector 5 and the cemented lens 6 are collinear and aligned with the center of the reflecting surface of the polarizing beam splitter 3. Both the reflector I 7 and the reflector II 9 are adjustable pitch reflectors with an adjustable pitch angle of ±2°. The thin-film beam splitter I 8 and the thin-film beam splitter II 15 are both mounted on a piezoelectric optical adjustment frame, which is fixed to the lens barrel structure. Under the action of the piezoelectric structure of the piezoelectric optical adjustment frame, the thin-film beam splitter I 8 and the thin-film beam splitter II 15 drive the lens to perform pitch adjustment with an adjustment accuracy of 0.5 μrad and an adjustment range of ±1.5 mrad. Piezoelectric optical adjustment frames are known to those skilled in the art. This device uses a piezoelectric optical adjustment frame and a thin-film beam splitter to form a "precision piezoelectric beam splitter" to achieve precise angle deflection with an accuracy of 0.5 μrad and a range of ±1.5 mrad.

[0030] In this embodiment, the microscope objective 13 is equipped with a displacement stage that drives the microscope objective 13 to move up and down. A piezoelectric ceramic is mounted on the microscope objective 13 to drive its movement in the Z-axis. This Z-axis movement allows the microscope objective to be displaced in the Z-axis, enabling automatic focusing of the probe or sample. The use of a piezoelectric ceramic to drive the Z-axis movement of the microscope objective 13 is known to those skilled in the art. Preferably, in this embodiment, the microscope objective 13 is threaded onto the microscope tube structure, and the displacement stage drives its up and down movement with a displacement accuracy of 1 μm and a stroke > 5 mm. The microscope objective 13 is preferably a high-magnification microscope objective.

[0031] In this embodiment, the device uses a precision piezoelectric beam splitter with a high-magnification microscope objective system. The entire optical tracking system of this device can reach a range of 300 μm, and its travel measurement range exceeds that of the prior art by 100 μm.

[0032] In this embodiment, the four-quadrant detector 5 is equipped with an XY-direction moving platform to facilitate automatic alignment with the position of the return light spot.

[0033] In this embodiment, the camera 11 is fixed to the lens barrel structure by a C-mount standard thread.

[0034] In this embodiment, the light emitted from the laser 1 passes sequentially through the adjustable aperture 2, the polarizing beam splitter 3, the quarter-wave plate I 4, the reflecting mirror I 7, the thin-film beam splitter I 8, and the microscope objective 13, and finally illuminates the probe 14; the light reflected back from the laser at the probe 14 passes sequentially through the microscope objective 13, the thin-film beam splitter I 8, the reflecting mirror I 7, the quarter-wave plate I 4, and the cemented lens 6, and is finally received by the four-quadrant detector 5, forming the monitoring optical path.

[0035] The coaxiality of the laser 1, adjustable aperture 2, polarizing beam splitter 3, quarter-wave plate I 4, reflector I 7, and thin-film beam splitter I 8 in the monitoring optical path is <0.5′. The distance between the optical components is kept compact, but not limited.

[0036] In the monitoring optical path of this embodiment, after the laser beam from laser 1 is emitted, it passes through an adjustable aperture 2, which limits the size of the emitted beam. Then it passes through a polarizing beam splitter 3, which reflects the backlight with a specific polarization state. Next, it passes through a quarter-wave plate I 4, which adds 1 / 4 wavelength phase to the laser, changing one polarization state. Then it passes through a reflector I 7, which reflects the laser beam onto a precision piezoelectric beam splitter. The precision piezoelectric beam splitter reflects the working laser beam into a microscope objective 13. On the other side, it reflects 50% of the backlight back to the detector and transmits 50% of the backlight to the camera 11. Then, the laser beam passes through the microscope objective 13, which focuses the laser beam into a diffraction-limited spot. The probe 14 is located on the focal plane of the objective. When the laser light is applied to the surface of the probe 14, it will be reflected. The reflected light passes through the microscope objective 13, the precision piezoelectric beam splitter, the mirror I 7, the quarter wave plate I 4, the polarizing beam splitter 3, and is reflected to the cemented lens 6, and finally converges into the four-image detector 5.

[0037] In this embodiment, a piezoelectric ceramic is added to the microscope objective 13, which can move the microscope objective in the z-direction. The purpose is to automatically focus the probe or sample. An XY-direction moving platform is added to the four-axis detector to facilitate automatic alignment with the reflected light spot position. By adding an electric displacement stage to the detector and microscope objective, fully automatic monitoring and scanning functions can be effectively achieved.

[0038] In this embodiment, the monitoring optical path of the device consists of a camera 11 whose output light passes sequentially through a quarter-wave plate II 16, a reflecting mirror II 9, a telescope lens 10, a thin-film beam splitter II 15, a thin-film beam splitter I 8, and a microscope objective 13, before finally illuminating the probe 14. The output light from the camera 11 is reflected on the surface of the probe 14, and the reflected light passes sequentially through the microscope objective 13, the thin-film beam splitter I 8, the thin-film beam splitter II 15, the telescope lens 10, the reflecting mirror II 9, and the quarter-wave plate II 16, before being received by the camera 11, thus forming the monitoring optical path.

[0039] In the monitoring optical path, the coaxiality of the thin-film beam splitter I 8, the microscope objective 13 and the probe 14 is guaranteed to be <0.5′, and the vertical distance between the microscope objective 13 and the probe 14 is 20mm±0.1mm.

[0040] In the monitoring optical path of this embodiment, the imaging light from the camera 11 passes through a quarter-wave plate II 16, which selects a specific polarization state for transmission and filters out stray light of non-polarization state. Then, it passes through a mirror II 9 and is reflected to a lens 10, which collimates the camera light. The camera light then passes through a precision piezoelectric beam splitter and is reflected to a microscope objective 13. The microscope objective 13 converges the camera light into a diffraction-limited spot, and the probe 14 is located on the focal plane of the objective.

[0041] The device in this embodiment adopts a coaxial vision monitoring system. The microscope objective 13 is both a laser working objective and a camera microscope objective, which improves the visual observation capability. At the same time, because of its short depth of focus, it can quickly insert needles into the AI ​​vision recognition function device.

[0042] Specific application examples: The device in this embodiment is an optical system for precision tracking and can be used in AFM (atomic force microscope) systems.

[0043] The above embodiments are only for illustrating the technical concept of this utility model and should not be construed as limiting the scope of protection of this utility model. Any modifications made to the technical solution based on the technical concept proposed by this utility model shall fall within the scope of protection of this utility model.

Claims

1. A probe scanning monitoring device, characterized in that, The optical components include: a laser (1), an adjustable aperture (2), a polarizing beam splitter (3), a quarter-wave plate I (4), a quadrant detector (5), a cemented lens (6), a mirror I (7), a thin-film beam splitter I (8), a camera (11), an illumination source (12), a quarter-wave plate II (16), a mirror II (9), a tube lens (10), a thin-film beam splitter II (15), and a microscope objective (13); all optical components are mounted on the tube structure. The laser beam emitted from the laser (1) passes sequentially through an adjustable aperture (2), a polarizing beam splitter (3), a quarter-wave plate I (4), a reflecting mirror I (7), a thin-film beam splitter I (8), and a microscope objective (13), finally illuminating the probe (14). The laser beam reflected from the probe (14) passes sequentially through the microscope objective (13), a thin-film beam splitter I (8), a reflecting mirror I (7), a quarter-wave plate I (4), and a cemented lens (6), finally being received by a quadrant detector (5), forming the monitoring optical path. The laser beam emitted from the camera (11) passes sequentially through a quarter-wave plate I (4), a thin-film beam splitter I (8), a reflecting mirror I (7), a quarter-wave plate I (4), and a cemented lens (6), finally being received by a quadrant detector (5), forming the monitoring optical path. The 4-wave plate II (16), mirror II (9), lens tube (10), thin film beam splitter II (15), thin film beam splitter I (8) and microscope objective (13) finally illuminate the probe (14); the light emitted from the camera (11) is reflected on the surface of the probe (14), and the reflected light passes through the microscope objective (13), thin film beam splitter I (8), thin film beam splitter II (15), lens tube (10), mirror II (9) and 1 / 4 wave plate II (16) in sequence, and is finally received by the camera (11), forming a monitoring optical path; Both the thin-film beam splitter I (8) and the thin-film beam splitter II (15) are mounted on a piezoelectric optical adjustment frame, which is fixed to the lens barrel structure. The optical axes of the quadrant detector (5) and the cemented lens (6) are collinear and aligned with the center of the reflecting surface of the polarizing beam splitter (3). The microscope objective (13) is provided with a displacement stage that drives the microscope objective (13) to move up and down, and a piezoelectric ceramic is installed on the microscope objective (13) to drive the microscope objective (13) to move in the Z direction.

2. The probe scanning monitoring device according to claim 1, characterized in that, The laser (1) is a semiconductor laser or a fiber laser.

3. The probe scanning monitoring device according to claim 1, characterized in that, Both the thin-film beam splitter I (8) and the thin-film beam splitter II (15) are driven by the piezoelectric optical adjustment frame to adjust the pitch of the lens. The adjustment accuracy is 0.5 μrad and the adjustment range is ±1.5 mrad.

4. The probe scanning monitoring device according to claim 1, characterized in that, The coaxiality of the laser (1), adjustable aperture (2), polarizing beam splitter (3), quarter wave plate I (4), mirror I (7) and thin film beam splitter I (8) in the monitoring optical path is <0.5′. The coaxiality of the thin film beam splitter I (8), microscope objective (13) and probe (14) in the monitoring optical path is <0.5′. The vertical distance between the microscope objective (13) and the probe (14) is 20mm±0.1mm.

5. The probe scanning monitoring device according to claim 1, characterized in that, Both mirror I (7) and mirror II (9) are adjustable pitch mirrors with an adjustable pitch angle of ±2°.

6. The probe scanning monitoring device according to claim 1, characterized in that, Both the quarter-wave plate I (4) and the quarter-wave plate II (16) can rotate around their own central axis.

7. The probe scanning monitoring device according to claim 1, characterized in that, The laser (1) is inserted into the lens barrel structure with an interference fit and fixed with a set screw.

8. The probe scanning monitoring device according to claim 1, characterized in that, The adjustable aperture (2) and the polarizing beam splitter (3) are fixed to the lens barrel structure by means of a fixed lens mount pressure ring or adhesive application.

9. The probe scanning monitoring device according to claim 1, characterized in that, The displacement accuracy of the stage on the microscope objective (13) is 1 μm, and the stroke is >5 mm.

10. The probe scanning monitoring device according to claim 1, characterized in that, The probe (14) is located on the focal plane of the microscope objective (13). The probe (14) is mounted on the microscope tube structure via a probe holder. An XY displacement stage is mounted on the probe (14).

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