Direct electron detector mounting levelling device and method
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BIOISLAND LAB
- Filing Date
- 2026-04-29
- Publication Date
- 2026-08-07
AI Technical Summary
若传感器平面与目标平面存在倾斜夹角，将导致一系列严重问题，例如，空间分辨率损失：在透射电镜等设备中，传感器倾斜会导致图像不同区域的放大倍率不一致，产生几何畸变，使得对样品微观结构的精确尺寸测量变得不可靠；信号收集效率不均：由于角度偏差，传感器表面各点距信号源的距离和入射角度不同，导致收集到的信号强度在传感器平面上分布不均，严重影响定量分析的准确性；以及，对焦困难与景深问题：在有限的景深范围内，倾斜会使传感器的一部分处于最佳焦平面，而另一部分则偏离焦点，导致图像整体模糊，无法同时获得全视野的清晰图像，极大影响观测效果
[0019]1. 实现高精度调平：通过一种结构，能够实现直接电子探测器相对于被测物表面微小倾角的精确补偿与校正，最终达到极高的平行度；
Smart Images
Figure CN122524862A_ABST
Abstract
Description
Technical Field
[0001] This invention discloses a detector mounting and leveling device, belonging to the field of optical measurement instrument technology. Background Technology
[0002] Direct electron detectors (such as direct electron detection cameras and electron impact CMOS) are core components of modern high-precision analytical equipment. Their working principle involves directly receiving signals from electrons, X-rays, or other particles and forming a two-dimensional image on the sensor surface. In such applications, the spatial relative position of the sensor's photosensitive surface to the sample surface or signal output plane, especially their parallelism, is a key factor determining the system's resolution, measurement accuracy, and signal collection efficiency. If the sensor plane is tilted at an angle to the target plane, it will lead to a series of serious problems, such as: loss of spatial resolution: in instruments like transmission electron microscopes, sensor tilt can cause inconsistent magnification in different areas of the image, resulting in geometric distortion and making precise dimensional measurements of the sample's microstructure unreliable; uneven signal collection efficiency: due to angular deviation, the distance from the signal source and the incident angle differ at various points on the sensor surface, leading to uneven distribution of the collected signal intensity on the sensor plane, severely affecting the accuracy of quantitative analysis; and focusing difficulties and depth-of-field issues: within a limited depth of field, tilt will cause one part of the sensor to be at the optimal focal plane, while another part will be off-focus, resulting in an overall blurred image, making it impossible to obtain a clear image of the entire field of view simultaneously, greatly affecting the observation results.
[0003] Currently, traditional methods for achieving high-precision leveling of such sensors have many limitations and cannot meet the requirements of modern precision analytical equipment. For example, mechanical fixed installation relies on the machining precision of the mounting flange and bracket. However, under complex operating conditions such as high vacuum and temperature fluctuations, mechanical deformation is unavoidable, leading to inaccurate initial installation angles. Furthermore, this method cannot be fine-tuned on-site; any adjustments require disassembling and reassembling the entire system, a cumbersome process that severely impacts the efficiency of equipment maintenance and optimization.
[0004] Manual adjustment with shims / feeler gauges: Parallelism is roughly adjusted by inserting metal shims of varying thicknesses at different locations. This method has low precision, is cumbersome, and heavily relies on the operator's experience and feel. In high-vacuum equipment, introducing additional shims may introduce the risk of outgassing contamination. Furthermore, this method cannot achieve precise control below the micrometer level and has poor repeatability.
[0005] Simple threaded set screw adjustment: While providing some adjustment capability, it suffers from fundamental flaws: Poor stability: The set screws are prone to loosening after equipment vibration or thermal cycling, causing the adjusted state to become invalid. This is fatal for analytical instruments that require long-term stable operation. Strong adjustment coupling: Adjusting the set screw in one direction will affect the tilt angle in other directions, making the leveling process like a "seesaw," making it difficult to quickly and independently converge to the optimal state. Lack of quantitative feedback: The adjustment process relies heavily on visual observation of preview images, lacking precise, digital parallelism feedback. This makes high-precision quantitative adjustment impossible, ultimately limiting the improvement of overall equipment performance.
[0006] For high-value precision equipment operating in special environments (such as high vacuum), the above methods involve cumbersome adjustment processes and make it difficult to quickly and reliably achieve micron-level or even higher parallelism requirements after installation.
[0007] Therefore, the purpose of this invention is to provide a direct electron detector mounting and adjustment scheme that enables rapid, accurate, and quantifiable operation and maintains long-term stability, thereby ensuring the final performance of high-end analytical testing equipment. Summary of the Invention
[0008] Based on the above objectives, the present invention first provides a direct electron detector leveling and mounting device, comprising: a PCB board for fixing the direct electron detector; a bottom structural component with three piezoelectric ceramic actuators arranged in an isosceles triangle on the bottom structural component for supporting the PCB board; an independent leveling fixture with a distance sensor configured in the leveling fixture for measuring distances to the photosensitive surface of the direct electron detector; and an automatic control system for real-time acquisition of distance measurement data from the distance sensor, calculating the angle and parallelism deviation between the plane of the direct electron detector and the measured plane based on the spatial geometric principle of three non-collinear points determining a plane, and outputting corresponding compensation values to the piezoelectric ceramic actuators to drive the piezoelectric ceramic actuators to extend and retract, thereby adjusting the spatial tilt angle of the direct electron detector and achieving leveling of the direct electron detector.
[0009] In a preferred embodiment, the direct electron detector is a planar direct electron detector. The planar direct electron detector described in this invention is an imaging device for transmission electron microscopy, capable of directly converting incident electron signals into digital signals without any intermediate conversion steps.
[0010] In a preferred embodiment, the photosensitive surface of the direct electron detector is rectangular, and four ranging sensors are configured on the leveling fixture, corresponding to the four corners of the rectangular photosensitive surface of the direct electron detector. More preferably, five ranging sensors are configured, including the center position where the two diagonals intersect, in addition to the four corners mentioned above.
[0011] In a preferred embodiment, the piezoelectric ceramic actuator has a stroke greater than 500 μm, for example 500-1000 μm, and an accuracy of 45-55 nm, specifically 50 nm.
[0012] In a preferred embodiment, the leveling fixture is made of aluminum alloy.
[0013] In a preferred embodiment, the programming language of the automatic control system is Python, C, C++, C#, or LabVIEW.
[0014] In a preferred embodiment, the ranging sensor is a laser displacement sensor, an eddy current sensor, or a spectral displacement sensor. The laser displacement sensor of this invention is a device that uses a laser beam as a medium to accurately measure the distance from an object to the sensor, or the position of the object's surface, without contact. It derives the displacement by calculating the time or phase change from laser emission to reception. The spectral displacement sensor of this invention is a high-precision sensor that calculates the distance to a target object absolutely and without contact by analyzing the interference spectrum signal returned after a broadband light source (or swept-frequency laser) illuminates the target object.
[0015] Secondly, the present invention provides a method for leveling and installing a direct electron detector using the aforementioned direct electron detector leveling and mounting device, the method comprising the following steps: S1. Quantitative Measurement: Place the leveling device in front of the direct electron detector, activate the distance sensor, acquire real-time distance data of multiple points on the surface of the direct electron detector, and transmit the real-time distance data to the automatic control system; S2. Adjustment: The automatic control system calculates the adjustment parameters of the three piezoelectric ceramic actuators based on the real-time distance data and the algorithm of the angle and parallelism deviation between the plane of the direct electron detector and the plane under test. It then controls the three piezoelectric ceramic actuators to make corresponding adjustments so that the distance difference between each point of the direct electron detector and the plane under test converges to the set tolerance range, thereby achieving the goal of keeping each point of the direct electron detector parallel to the plane under test.
[0016] In a preferred embodiment, the adjustment step of S2 is as follows: S21. Position the ranging sensors at the four corners of the rectangle of the photosensitive surface of the direct electron detector, and at the center of the intersection of the two diagonals. Measure the initial distances from each ranging sensor to the surface of the direct electron detector as La, Lb, Lc, Ld, and Le, respectively. Here, line ab is parallel to line BC; points a and b are the two points on the connecting line of the two piezoelectric ceramic actuators located at the two base corners of the three piezoelectric ceramic actuators arranged in an isosceles triangle; points c and d are the two points on the connecting line of the one piezoelectric ceramic actuator located at the apex of the three piezoelectric ceramic actuators arranged in an isosceles triangle; e is the center of the intersection of the two diagonals; and B and C are the actuators located at the two base corners of the three piezoelectric ceramic actuators arranged in an isosceles triangle. S22. Adjust actuators B and C, which are located at the two base corners of the three piezoelectric ceramic actuators arranged in an isosceles triangle, so that the ranging value La is equal to Lb; S23. Adjust one of the three piezoelectric ceramic actuators distributed in an isosceles triangle, located at the vertex, such that the ranging values La, Lb, Lc, and Ld are equal. S24. Synchronously adjust piezoelectric ceramic actuators A, B, and C to ensure that all ranging values reach the preset target.
[0017] In a preferred embodiment, the direct electron detector has an optical imaging function, and after S2, it also includes effect verification and secondary calibration S3: remove the leveling fixture, install the optical verification fixture containing the lens and the standard resolution plate, acquire images through the direct electron detector, and intuitively verify the leveling effect based on the consistency of the overall image clarity.
[0018] This invention provides a mounting and leveling scheme for a direct electron detector. This scheme, through an innovative combination of three-point support, quantitative measurement, and automatic control, solves the core problems of existing technologies, such as low adjustment accuracy, reliance on experience, and poor stability, achieving high-precision automatic leveling at the micrometer level. It has the following superior technical effects.
[0019] 1. Achieve high-precision leveling: Through a structure, it is possible to achieve precise compensation and correction of the minute tilt angle of the direct electronic detector relative to the surface of the object being measured, ultimately achieving extremely high parallelism; 2. Provide quantitative operational guidance: Transform the adjustment process from an experience-based "trial and error" approach to a quantifiable operation with clear, quantifiable feedback, reducing reliance on operator skills; 3. Reduce overall costs: Through ingenious structural design, while ensuring high precision and high stability, the use of expensive optical adjustment mechanisms or precision-machined parts is avoided, effectively controlling manufacturing and maintenance costs; 4. Ensure excellent repeatability and stability: The adjustment mechanism has a reliable self-locking or locking function to ensure that the adjusted level will not drift during vibration and long-term use, thus guaranteeing the consistency and reliability of measurement results. Attached Figure Description
[0020] Figure 1 This is a schematic diagram illustrating the three-point adjustment principle of the direct electron detector mounting structure of the present invention; Figure 2 This is a schematic diagram of the leveling fixture and its multi-point measurement principle of the present invention; Figure 3 This is a schematic diagram of the automatic control system of the present invention; Figure 4 A schematic diagram of the algorithm for the angle and parallelism deviation between the plane of the direct electron detector and the plane under test; Figure 5 This is a schematic diagram of the control flow of the control system; Figure 6 This is a schematic diagram showing the placement of the standard resolution plate used for imaging effect verification in this invention.
[0021] Digital Identification Description: 1. Direct Electronic Detector, 2. PCB Board, 3. Bottom Structural Components, 4. Piezoelectric Ceramic Actuator, 5. Locking Screw, 6. Leveling Fixture, 7. High-Precision Range Sensor, 8. Lens, 9. Standard Resolution Board, 10. Optical Verification Fixture. Detailed Implementation
[0022] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as a result of the description. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of protection defined by the claims of the present invention.
[0023] This invention provides a high-precision leveling device and method for a direct electron detector based on three-point support and quantization feedback. The device comprises three main parts: an installation structure system, a measurement and calibration system, and an automatic control system.
[0024] (1) Installation structure system like Figure 1 As shown, the direct electron detector 1 is fixed on a PCB board 2, which is supported by a bottom structural component 3 via three piezoelectric ceramic actuators 4 arranged in a stable isosceles or equilateral triangle. The piezoelectric ceramic actuators 4 are located below the PCB board 2. The piezoelectric ceramic actuators 4 serve as the core adjustment unit, achieving nanometer-level precision in telescoping displacement through voltage control, thereby fine-tuning the detector's spatial tilt angle. This three-point support structure constitutes a statically determinate system, effectively eliminating over-constraint and achieving decoupled adjustment.
[0025] (2) Measurement and calibration system like Figure 2 As shown, the system includes an independent high-precision leveling fixture 6, which integrates multiple (preferably 4-5) high-precision ranging sensors 7. In one specific implementation, the high-precision ranging sensors 7 can be laser displacement sensors or eddy current sensors. The sensor measurement points are precisely arranged, corresponding to the four corners of the detector's photosensitive surface and the center position where the two diagonals intersect. Before use, the leveling fixture needs to be pre-placed on the plane to be measured to complete the sensor zero-point calibration, ensuring that the measurement reference is consistent with the plane to be measured.
[0026] (3) Automatic control system like Figure 3 As shown, the system collects distance data from each ranging sensor in real time. Based on the spatial geometric principle that "three non-collinear points determine a plane", it accurately calculates the angle and parallelism deviation between the detector plane and the measured plane, and outputs corresponding compensation values to each piezoelectric ceramic actuator to achieve fully automatic closed-loop adjustment.
[0027] (4) Leveling method The leveling method of the present invention has the following steps: 1) Leveling fixture calibration and zeroing; 2) Quantitative measurement: Place the measuring and leveling device in front of the detector, start the distance sensor, and obtain real-time distance data of multiple points on the detector surface; 3) The automatic control system independently controls three piezoelectric ceramic actuators to adjust according to the measurement data, so that the distance difference between each point of the detector and the measured plane converges to the set tolerance range (10um or less), achieving high-precision parallelism, and automatically stops after reaching the set accuracy.
[0028] like Figure 4 As shown, the three piezoelectric ceramic actuators are arranged in an isosceles or equilateral triangle. Assume side length AB = AC, and the line connecting ab and BC is parallel to the line connecting BC. The ranging sensors correspond to the four corners of the rectangle of the photosensitive surface of the direct electron detector, and the center position where the two diagonals intersect. Assume the initial distances from each ranging sensor to the surface of the direct electron detector are La, Lb, Lc, Ld, and Le.
[0029] The leveling algorithm performs the following steps in sequence: By adjusting actuators B and C, the ranging value La is made equal to Lb; By adjusting actuator A, the ranging values La, Lb, Lc, and Ld are made equal; By synchronously adjusting actuators A, B, and C, all ranging values are made to reach the preset target.
[0030] Figure 5 A schematic diagram of the control flow of control system 10 is given.
[0031] (5) Verification methods After leveling, the full-field imaging clarity can be visually verified by acquiring images from a resolution panel, providing dual assurance. For example... Figure 6 As shown, if detector 1 has optical imaging function, the leveling fixture 6 can be removed after leveling, and an optical verification fixture 10 containing lens 8 and standard resolution plate 9 can be installed in the same position. The detector can collect images and the leveling effect can be intuitively verified based on the consistency of the overall image clarity.
Claims
1. A direct electron detector leveling and mounting device, characterized in that, The direct electron detector leveling and mounting device includes: a PCB board for fixing the direct electron detector; a bottom structural component with three piezoelectric ceramic actuators arranged in an isosceles triangle on the bottom structural component to support the PCB board; an independent leveling fixture with a distance sensor configured in the leveling fixture for measuring distances to the photosensitive surface of the direct electron detector; and an automatic control system for real-time acquisition of distance measurement data from the distance sensor, calculating the angle and parallelism deviation between the plane of the direct electron detector and the measured plane based on the spatial geometric principle of three non-collinear points determining a plane, and outputting corresponding compensation values to the piezoelectric ceramic actuators to drive them to extend or retract, thereby adjusting the spatial tilt angle of the direct electron detector and achieving leveling of the direct electron detector.
2. The direct electron detector leveling and mounting device according to claim 1, characterized in that, The direct electron detector is a surface array direct electron detector.
3. The direct electron detector leveling and mounting device according to claim 1, characterized in that, The photosensitive surface of the direct electron detector is rectangular, and four ranging sensors are configured on the leveling fixture, each corresponding to one of the four corners of the rectangular photosensitive surface of the direct electron detector.
4. The direct electron detector leveling and mounting device according to claim 1, characterized in that, The piezoelectric ceramic actuator has a stroke greater than 500 μm and an accuracy of 40-60 nm.
5. The direct electron detector leveling and mounting device according to claim 1, characterized in that, The leveling fixture is made of aluminum alloy.
6. The direct electron detector leveling and mounting device according to claim 1, characterized in that, The programming language for the automatic control system is Python, C, C++, C#, or LabVIEW.
7. The direct electron detector leveling and mounting device according to claim 1, characterized in that, The ranging sensor is a laser displacement sensor, an eddy current sensor, or a spectral displacement sensor.
8. A method for leveling and installing a direct electron detector using the leveling and mounting apparatus according to any one of claims 1-7, characterized in that, The method includes the following steps: S1. Quantitative Measurement: Place the leveling device in front of the direct electron detector, activate the distance sensor, acquire real-time distance data of multiple points on the surface of the direct electron detector, and transmit the real-time distance data to the automatic control system; S2. Adjustment: The automatic control system calculates the adjustment parameters of the three piezoelectric ceramic actuators based on the real-time distance data and the algorithm of the angle and parallelism deviation between the plane of the direct electron detector and the plane under test. It then controls the three piezoelectric ceramic actuators to make corresponding adjustments so that the distance difference between each point of the direct electron detector and the plane under test converges to the set tolerance range, thereby achieving the goal of keeping each point of the direct electron detector parallel to the plane under test.
9. The method according to claim 8, characterized in that, The adjustment steps for S2 are as follows: S21. Position the ranging sensors at the four corners of the rectangle of the photosensitive surface of the direct electron detector, and at the center of the intersection of the two diagonals. Measure the initial distances from each ranging sensor to the surface of the direct electron detector as La, Lb, Lc, Ld, Le, where line ab is parallel to line BC; points a and b are two points on the connecting line of the two piezoelectric ceramic actuators located at the two base corners of the three piezoelectric ceramic actuators arranged in an isosceles triangle; points c and d are two points on the connecting line of the one piezoelectric ceramic actuator located at the apex of the three piezoelectric ceramic actuators arranged in an isosceles triangle; e is the center of the intersection of the two diagonals; and B and C are the actuators located at the two base corners of the three piezoelectric ceramic actuators arranged in an isosceles triangle. S22. Adjust actuators B and C, which are located at the two base corners of the three piezoelectric ceramic actuators arranged in an isosceles triangle, so that the ranging value La is equal to Lb; S23. Adjust one of the three piezoelectric ceramic actuators distributed in an isosceles triangle, located at the vertex, such that the ranging values La, Lb, Lc, and Ld are equal. S24. Synchronously adjust piezoelectric ceramic actuators A, B, and C to ensure that all ranging values reach the preset target.
10. The method according to claim 8, characterized in that, The direct electron detector has optical imaging capabilities. After S2, it also includes effect verification and secondary calibration S3: remove the leveling fixture, install the optical verification fixture containing the lens and standard resolution plate, acquire images through the direct electron detector, and intuitively verify the leveling effect based on the consistency of the overall image clarity.