Variable diaphragm based on MEMS technology and working method thereof

Abstract

The invention relates to a diaphragm, and particularly provides an MEMS technology-based variable diaphragm and a working method thereof, the variable diaphragm comprises a first part and a second part, the first part and the second part are combined to form the diaphragm, and when the first part and the second part are separated, the aperture of the diaphragm is changed; two sides of the first part and the second part are respectively fixed on the body through a cantilever beam, and the first part, the second part and the cantilever beam are suspended; the driving unit is used for driving the first part and the second part to separate and approach; the body is provided with a light through hole, and electrons sequentially penetrate through the diaphragm and the light through hole. The device has the advantages of high adjustment precision and the like, and is applied to electron microscopes.

Description

Technical Field

[0001] This invention relates to liquid detection technology, and more particularly to a variable aperture and method based on MEMS technology. Background Technology

[0002] As an optical system, an electron microscope requires switching between different sizes of apertures to obtain different imaging effects. A smaller aperture is used when high resolution is required, and a larger aperture is used when high signal intensity is required.

[0003] Currently, there are two main methods for switching the aperture: 1. Mechanical switching: A series of apertures of different sizes are etched on a straight strip of material. During use, the apertures are mechanically moved to switch between them. This method is relatively cumbersome and prone to misalignment.

[0004] 2. Magnetic deflection switching: A ring of apertures of different sizes is etched onto a circular material. The aperture is placed on the optical axis, and an electromagnetic coil is used to deflect it to switch between apertures. When the aperture is off-axis, the electromagnetic coil deflects electrons into the aperture, and then the electromagnetic coil deflects the electrons back onto the optical axis. This does not produce mechanical movement, but it will introduce some aberrations due to the deflection of the electrons. Summary of the Invention

[0005] To address the shortcomings of the existing technical solutions, this invention provides a variable aperture based on MEMS technology.

[0006] The objective of this invention is achieved through the following technical solution: A variable aperture based on MEMS technology, the variable aperture comprising: The first part and the second part together form an aperture stop, and the aperture of the aperture stop changes when the first part and the second part are separated. The cantilever beam has the first part and the second part fixed to the body on both sides by the cantilever beam, and the first part, the second part and the cantilever beam are suspended in the air; A driving unit is used to drive the first part and the second part to separate and approach each other; The body has a light-transmitting hole, through which electrons pass sequentially between the aperture and the light-transmitting hole, and the cantilever beam is fixed to the body.

[0007] The present invention also aims to provide a method for operating the variable aperture, which is achieved through the following technical solutions.

[0008] The variable aperture working method based on the present invention is as follows: The driving module drives the first part and the second part respectively, thereby increasing the aperture of the aperture. Electrons pass through the aperture and the light-transmitting hole in sequence.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The electrostatic voltage switching is simple, the power consumption is low, the MEMS structure is small in size and has low inertia, which enables fast response and can complete the aperture adjustment or switching action in a short time. 2. Microelectromechanical apertures do not require spatial movement, ensuring precise positioning; 3. The use of MEMS technology enables mass production with good consistency, which in turn allows for stable operation of the electron microscope and good repeatability of imaging quality.

[0010] Using semiconductor manufacturing processes, high-precision processing at the sub-micron or even nanometer level can be achieved, allowing for precise control of the aperture size and ensuring that the aperture edges are very neat and smooth. This enables more precise control of the electron beam throughput and beam spot shape, thereby improving the imaging quality of the electron microscope. 4. Coaxial switching of large and small apertures eliminates the need to deflect the electron beam and introduces no additional aberrations. Attached Figure Description

[0011] The disclosure of this invention will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are merely illustrative of the technical solutions of this invention and are not intended to limit the scope of protection of this invention. In the drawings: Figure 1 This is a schematic diagram of the structure of the variable aperture based on MEMS technology according to the present invention; Figure 2 This is a schematic diagram of the 3D structure of the variable aperture based on MEMS technology according to the present invention; Figure 3 This is a schematic diagram of a local 3D structure of a variable aperture based on MEMS technology according to the present invention; Figure 4 This is a schematic diagram of the working state of the variable aperture based on MEMS technology according to the present invention; Figure 5 This is a cross-sectional schematic diagram of a cantilever beam according to the present invention; Figure 6 This is a cross-sectional schematic diagram of the first electrode according to the second part of the present invention. Detailed Implementation

[0012] Figures 1-6The following description illustrates optional embodiments of the invention to teach those skilled in the art how to implement and reproduce the invention. Some conventional aspects have been simplified or omitted to teach the technical solutions of the invention. Those skilled in the art should understand that variations or substitutions derived from these embodiments will be within the scope of the invention. Those skilled in the art should understand that the following features can be combined in various ways to form multiple variations of the invention. Therefore, the invention is not limited to the optional embodiments described below, but is defined only by the claims and their equivalents.

[0013] Example 1

[0014] This embodiment presents a variable aperture based on MEMS technology, such as... Figure 1 As shown, it includes: The first part 1031 and the second part 1032 have notches on opposite sides, which together form an aperture 107. When the first part 1031 and the second part 1032 are separated, the aperture of the aperture 107 changes.

[0015] The first part 1031 and the second part 1032 are fixed to the body 108 on both sides by cantilever beams 101, and the first part 1031, the second part 1032 and the cantilever beams 101 are suspended in the air.

[0016] The driving unit is used to drive the first part 1031 and the second part 1032 to separate and approach each other, thereby adjusting the aperture of the aperture 107.

[0017] The body 108 has a light-transmitting hole, through which electrons pass sequentially between the aperture 107 and the light-transmitting hole.

[0018] To precisely and stably adjust the aperture of the aperture stop 107, the driving unit further includes: The first electrode 106 is respectively disposed on the body 108 on both sides of the first part 1031 and the second part 1032.

[0019] The second electrode 606 is disposed on the first part 1031 and the second part 1032 respectively.

[0020] The power supply is connected to the first electrode 106 and the second electrode 606 respectively. When the power is applied, the first electrode 106 and the second electrode attract each other, and the first part 1031 and the second part 1032 move away from each other, thereby adjusting the aperture of the aperture 107.

[0021] To facilitate the application of voltage, the drive unit further includes: The third electrode 100 is disposed on the body 108, and the power supply is connected to the third electrode 100.

[0022] like Figure 5As shown, a conductive layer 509 is disposed on an insulated cantilever beam 101, and the third electrode 100 is connected to the second electrode through the conductive layer 509.

[0023] To further block electrons, the variable aperture also includes: An electron blocking layer 104 is disposed on the surfaces of the first portion 1031 and the second portion 1032.

[0024] To better drive the first part 1031 and the second part 1032, further, as Figure 6 As shown, the first portion 1031 and the second portion 1032 have an upward strip-shaped first protrusion 1033 on the side adjacent to the first electrode 106, and the second electrode 606 wraps around the first protrusion 1033.

[0025] The body 108 has an upward-facing, strip-shaped second protrusion 1081 on the side facing the first portion 1031 and the second portion 1032, and the first electrode 106 wraps around the second protrusion 1081.

[0026] An insulating layer 1086 is disposed between the first electrode 106 and the second electrode 606, and is attached to the first electrode 106.

[0027] To rapidly and stably manufacture variable apertures, further, such as Figures 5-6 As shown, the body 108 includes an insulating substrate layer 1083 and a metal substrate layer 1084. An insulating dielectric layer 1085 is disposed between the first electrode 106 and the third electrode 100 and the insulating substrate layer 1083. An insulating cantilever beam 101 is connected to the insulating dielectric layer 1085.

[0028] like Figures 2-3 As shown, the insulating substrate layer 1083 has a first light-transmitting hole 405, and the metal substrate layer has a second light-transmitting hole 406. The diameter of the first light-transmitting hole 405 is larger than that of the second light-transmitting hole 406 to prevent electrons from accumulating charge on the insulating substrate layer 1083. Electrons pass sequentially through the aperture 107, the first light-transmitting hole 405, and the second light-transmitting hole 406.

[0029] Based on the variable aperture working method of this embodiment, the working method is as follows: The driving module drives the first part 1031 and the second part 1032 respectively, so that the aperture of the aperture increases and exposes a larger light-transmitting hole on the main body 108.

[0030] Electrons pass through the aperture 107 and the light-transmitting hole in sequence.

[0031] Example 2

[0032] Application examples of the variable aperture and method based on MEMS technology in this invention.

[0033] In this application example, such as Figure 1 As shown, the first electrode 106 is T-shaped and is respectively disposed on the left and right sides of the first part 1031 and the second part 1032. The third electrode 100 is strip-shaped and is respectively disposed on the upper and lower sides of the first part 1031 and the second part 1032.

[0034] The first part 1031 is connected to the third electrode 100 on both sides by two insulated cantilever beams 101 (material is SU-8). The length of one end of the cantilever beam is 1750μm. The second part 1032 is connected to the third electrode 100 on both sides by two insulated cantilever beams 101.

[0035] The electron blocking layer 104 is made of molybdenum and has a thickness of 5 μm. Molybdenum has a high melting point and good shape retention. It is deposited on the surfaces of the first part 1031 and the second part 1032 to block electrons.

[0036] The first part 1031 and the second part 1032 each have a semi-circular notch on opposite sides, with an aperture size of 5μm-30μm, forming an aperture 107. When the first part 1031 and the second part 1032 are driven away from each other by an external force, the aperture 107 is enlarged, as shown below. Figure 4 As shown, this improves electron transmittance.

[0037] like Figures 2-3 As shown, the insulating substrate layer 1083 of the body 108 has a first light-transmitting hole 405, and the metal substrate layer 1084 has a second light-transmitting hole 406. The diameter of the first light-transmitting hole 405 is larger than that of the second light-transmitting hole 406 to prevent electrons from forming charge accumulation on the insulating substrate layer 1083.

[0038] like Figure 5 As shown, the insulated cantilever beam 101 is made of SU-8 material, which has a low Young's modulus and large displacement. In this example, with an operating voltage of 32V, it can move more than 60μm with a deformation of less than 0.1%, and can be reused a maximum of [number missing]. above.

[0039] The cantilever beam 101 connects to the insulating dielectric layer below the third electrode 100. The conductive layer 509 is disposed on the surface of the cantilever beam 101 and connects the third electrode 100 and the second electrode 606. The first part 1031, the second part 1032 and the cantilever beam 101 are suspended, and the distance between them and the insulating substrate layer 1083 is 5 μm.

[0040] like Figure 6As shown, the insulating substrate 1083 is made of gallium nitride and has a thickness of 3 μm. The metal substrate 1084 is made of molybdenum and has a thickness of 50 μm. An insulating dielectric layer 1085 is disposed between the first electrode 106 and the insulating substrate 1083.

[0041] The first portion 1031 has an upward-facing, strip-shaped first protrusion 1033 on the side adjacent to the first electrode 106, and the second electrode 606 covers the first protrusion 1033 and the first portion 1031. The insulating dielectric layer 1085 has an upward-facing, strip-shaped second protrusion 1081 on the side adjacent to the first portion 1031 and the second portion 1032, and the first electrode 106 covers the second protrusion 1081. The design of the first electrode 106 and the second electrode 606 (including the protrusions) increases the electrode area and improves the electrostatic force between the first electrode 106 and the second electrode 606, thereby better driving the first portion 1031 and the second portion 1032.

[0042] The insulating layer 1086 is made of SU-8 material, with a width of 1μm and a height of 45μm. It is attached to the first electrode 106, that is, it is disposed between the first electrode 106 and the second electrode 606.

[0043] The first electrode 106, the second electrode 606, the conductive layer 509 and the third electrode 100 are formed by gold plating, with a gold film thickness of 0.1 μm.

[0044] Power supply 102 applies a 32V voltage between the third electrode 100 (positive) and the first electrode 106 (negative).

[0045] When the first electrode 106 and the third electrode 100 are energized, an electrostatic capacitor is formed between the second electrode 606 on the first part 1031 and the first electrode 106. The generated electrostatic force causes an attraction between the first part 1031 (second part 1032) and the first electrode 106. The electrostatic torque acts on the cantilever beam 101, causing the cantilever beam connecting the first part 1031 and the second part 1032 to deform to the left and right respectively. This causes the first part 1031 and the second part 1032 to move away from each other, and the small aperture 107 opens, exposing the second light-transmitting hole 406 below, thus realizing the switching between apertures.

[0046] The variable aperture working method of this embodiment is as follows: The first electrode 106 and the third electrode 100 are energized with a voltage of 32V.

[0047] An electrostatic capacitor is formed between the second electrode 606 and the first electrode 106 on the first part 1031. The generated electrostatic force causes an attraction between the first part 1031 (second part 1032) and the first electrode 106. The electrostatic torque acts on the cantilever beam 101, causing the cantilever beam 101 connecting the first part 1031 and the second part 1032 to deform to the left and to the right respectively, thereby causing the first part 1031 and the second part 1032 to move away from each other, and the second electrode 606 is attached to the insulating layer 1085.

[0048] When the small aperture 107 opens, the second light-transmitting hole 406 below is exposed, enabling the switching between apertures.

[0049] When power supply 102 stops supplying power, cantilever beam 101 deforms, and the first part 1031 and the second part 1032 approach and make contact.

[0050] The terms left, right, top, and bottom are used only to express the positional relationship between the electrode and the first part 1031 (second part 1032), and do not necessarily mean that they are in the up, down, left, or right directions of the first part 1031 (second part 1032).

Claims

1. A variable aperture based on MEMS technology, characterized in that, The variable aperture includes: The first part and the second part together form an aperture, and the aperture of the aperture changes when the first part and the second part are separated. The cantilever beam has the first part and the second part fixed to the body on both sides by the cantilever beam, and the first part, the second part and the cantilever beam are suspended in the air; A driving unit is used to drive the first part and the second part to separate and approach each other; The body has a light-transmitting hole, through which electrons pass sequentially between the aperture and the light-transmitting hole, and the cantilever beam is fixed to the body.

2. The variable aperture based on MEMS technology according to claim 1, characterized in that, The driving unit includes: The first electrode is disposed on the body on both sides of the first part and the second part respectively; The second electrode is disposed on the first part and the second part respectively; A power source, which is connected to the first electrode and the second electrode respectively.

3. The variable aperture based on MEMS technology according to claim 2, characterized in that, The drive unit further includes: A third electrode is disposed on the body, and the power supply is connected to the third electrode; A conductive layer is disposed on an insulated cantilever beam, and the third electrode is connected to the second electrode through the conductive layer.

4. The variable aperture based on MEMS technology according to claim 3, characterized in that, The variable aperture also includes: An electron blocking layer is disposed on the surfaces of the first portion and the second portion.

5. The variable aperture based on MEMS technology according to claim 2, characterized in that, The first part and the second part have an upward strip-shaped first protrusion on the side adjacent to the first electrode, and the second electrode wraps around the first protrusion; The body has an upward-facing, strip-shaped second protrusion on the side facing the first and second portions, and the first electrode wraps around the second protrusion; An insulating layer is disposed between the first electrode and the second electrode, and is attached to the first electrode or the second electrode.

6. The variable aperture based on MEMS technology according to claim 3, characterized in that, The body includes an insulating substrate layer and a metal substrate layer. An insulating dielectric layer is disposed between the first electrode and the third electrode and the insulating substrate layer. An insulating cantilever beam connects the insulating dielectric layer. The insulating substrate layer has a first light-transmitting hole, and the metal substrate layer has a second light-transmitting hole. The diameter of the first light-transmitting hole is larger than that of the second light-transmitting hole, and electrons pass through the aperture, the first light-transmitting hole, and the second light-transmitting hole in sequence.

7. The variable aperture based on MEMS technology according to claim 6, characterized in that, The first electrode is T-shaped and is respectively disposed on the left and right sides of the first part and the second part, and the third electrode is strip-shaped and is respectively disposed on the upper and lower sides of the first part and the second part.

8. The variable aperture based on MEMS technology according to claim 1 or 7, characterized in that, The first and second parts are fixed to the upper side of the main body by two cantilever beams on one side, and to the lower side of the main body by two cantilever beams on the other side.

9. A method for operating the variable aperture based on claim 1, wherein the method is as follows: The driving module drives the first part and the second part respectively, thereby increasing the aperture of the aperture. Electrons pass through the aperture and the light-transmitting hole in sequence.

10. The working method according to claim 9, characterized in that, The driving unit includes a first electrode, a second electrode, and a power supply. The first electrode is respectively disposed on the body on both sides of the first part and the second part; the second electrode is respectively disposed on the first part and the second part; and the power supply is respectively connected to the first electrode and the second electrode. The method for driving the first part and the second part is as follows: The power source applies a voltage between the first electrode and the second electrode, causing the first electrode and the second electrode to attract each other, deforming the cantilever beam, moving the first part and the second part away from each other, and increasing the aperture of the aperture.

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