CN218848536U - Illumination structure and detection system for detecting surface defects of MEMS scanning microcrystal - Google Patents

Abstract

The utility model discloses a detect microcrystalline surface defect's of MEMS scanning illumination structure and detecting system, this illumination structure is including setting up at least one of MEMS scanning micrite top following lighting device: a first illumination device, which directly irradiates light rays on the surface of the MEMS scanning microcrystal at a set angle; and the second lighting device is used for diffusely reflecting the light and then irradiating the light on the surface of the MEMS scanning microcrystal. The lighting structure can configure the type of the lighting device contained in the lighting structure according to the detection requirement, so that the surface of the MEMS scanning microcrystal is irradiated to detect whether the defect exists. The detection system can detect defects of the whole area of the surface of the MEMS scanning microcrystal and meet the high-precision detection requirement.

Description

Illumination structure and detection system for detecting surface defects of MEMS scanning microcrystal

Technical Field

The utility model relates to a micrite detects technical field, especially relates to a detect illumination structure and detecting system of MEMS scanning micrite's surface defect.

Background

MEMS (Micro electro mechanical System) Micro galvanometer, also known as MEMS scanning mirror, MEMS Micro mirror, can be used for laser radar. Compared with a polygon mirror and a swing mirror used for a mechanical laser radar, the size of the MEMS micro-vibration mirror is greatly reduced, but the optical aperture and the scanning angle of the MEMS laser radar are also limited, and the angle of field is also reduced. To achieve maximum optical aperture, the MEMS mirror size needs to be increased. But the larger the chip size, the higher the cost and the more sensitive to defects. The yield of chips manufactured from the same wafer is inversely proportional to the size of a single chip, thereby greatly increasing the manufacturing difficulty and cost. Therefore, the detection requirement and difficulty of the MEMS scanning microcrystal can be further improved.

At present, the light source used for the appearance defect detection of the conventional MEMS scanning microcrystal is generally a single point light source. The whole area of the MEMS scanning microcrystal cannot be detected, only the surface silicon oxide area can be detected, other areas of the MEMS scanning microcrystal, such as a coil area, are shown in figures 2 and 3, due to process reasons, the gold plating thickness of the microcrystal coil area has certain difference, images shot under a point light source have very large gray value difference, the mirror surface contamination cannot be observed when the point light source is shot in the microcrystal mirror surface area, so that the algorithm cannot perform automatic optical detection on the whole area of the product, and the coil and the mirror surface area can only be manually visually detected. The manual detection mode generally has low detection efficiency and cannot meet the capacity requirement. Moreover, the detection standard is not uniform and the detection accuracy is poor due to the inevitable human error in the manual detection. In addition, long-time detection causes fatigue of detection personnel, resulting in uneven detection results.

SUMMERY OF THE UTILITY MODEL

In order to solve one or more technical problem as mentioned above at least, the utility model discloses an illumination structure and detecting system that detect the surface defect of micrite of MEMS scanning has been proposed in a plurality of aspects to solve single light source and can't detect and artifical detection accuracy is poor, inefficiency scheduling problem to the whole region of scanning the micrite of MEMS.

In a first aspect, the present invention provides an illumination structure for detecting surface defects of MEMS scanning crystallites, comprising at least one of the following illumination devices disposed above the MEMS scanning crystallites: a first illumination device, which directly irradiates light on the surface of the MEMS scanning microcrystal at a set angle; and the second lighting device is used for diffusely reflecting the light and then irradiating the light on the surface of the MEMS scanning microcrystal.

In one embodiment, the light emitted by the first illumination device is at an angle of less than 45 ° to the surface of the MEMS scanning micro-crystal.

In one embodiment, the light sources in the first lighting device are arranged in a circular ring.

In one embodiment, the second lighting device is an inverted hemispherical shell.

In one embodiment, when the lighting structure comprises the first lighting device and a second lighting device, the second lighting device is disposed above the first lighting device.

In one embodiment, a third illumination device is also included that illuminates the surface of the MEMS scanning micro-crystal with a point light source.

In one embodiment, when the lighting structure comprises the third lighting device and the first lighting device or/and the second lighting device, the third lighting device is disposed above the first lighting device or/and the second lighting device.

In a second aspect, the present invention provides a system for detecting surface defects of MEMS scanned crystallites, comprising: the lighting structure as described above; a camera disposed at an upper portion of the illumination structure for capturing an image of the surface of the MEMS scanning micro-crystal as illuminated by the illumination structure; and the control module is electrically connected with the illumination structure and the camera and used for controlling the illumination of the illumination structure on the surface of the MEMS scanning microcrystal and controlling the shooting of the camera on the surface of the MEMS scanning microcrystal and judging whether the surface of the MEMS scanning microcrystal has defects or not based on the image of the surface of the MEMS scanning microcrystal shot by the camera.

In one embodiment, a telecentric lens is disposed on the camera.

In one embodiment, the third illuminator is disposed within the telecentric lens.

In one embodiment, the camera is a high resolution camera with a resolution of 3.2 μm.

In one embodiment, a stage is also included for placing the MEMS scanning micro-crystal.

In one embodiment, the device further comprises an alarm device which is electrically connected with the control module; and when the control module judges that the surface of the MEMS scanning microcrystal has defects, the alarm device gives an alarm.

The embodiment of the utility model provides an illumination structure and detecting system for MEMS scanning micrite surface defect, it improves mainly to lie in through first lighting device, the illumination structure that second lighting device and third lighting device constitute, can utilize the characteristics of every light source to shine MEMS scanning micrite surface's corresponding detection area as required, and utilize the camera to shoot by the MEMS scanning micrite surface of being shone, thereby carry out clear formation of image to each detection area of MEMS scanning micrite surface, make control module can be according to the clear image of the MEMS scanning micrite surface of shooing, carry out accurate analysis and judgement to MEMS scanning micrite surface's defect, and detection standard is unified. The detection system can not only detect defects of the whole area of the MEMS scanning microcrystal surface, but also detect and meet the high-precision detection requirement. The system adopts the mode that the control module automatically judges the defects to replace manual visual inspection, has high detection efficiency, saves labor cost, can realize large-batch automatic detection, and has high detection result accuracy.

Drawings

The above and other objects, features and advantages of exemplary embodiments of the present disclosure will become readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. Several embodiments of the present disclosure are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar or corresponding parts and in which:

fig. 1 is a schematic structural diagram of a MEMS scanning microcrystal according to an embodiment of the present invention;

fig. 2 and 3 are images taken when a point source illuminates the surface of a MEMS scanning crystallite in an embodiment of the invention;

fig. 4 is a schematic optical path diagram of the illumination of the surface of the MEMS scanning micro-crystal by the first illumination device in the embodiment of the present invention;

fig. 5 is a schematic optical path diagram of the surface irradiation of the MEMS scanning micro-crystal by the second illumination device in the embodiment of the present invention;

fig. 6 is a schematic structural view of an illumination structure and a detection system for detecting surface defects of MEMS-scanned crystallites in an embodiment of the present invention;

fig. 7 is an image of a first detection area of a MEMS scanning micro-crystal detected by a first illumination device according to an embodiment of the present invention;

fig. 8 is an image of a second detection area of the MEMS scanning micro-crystal detected by a second lighting device according to an embodiment of the present invention;

fig. 9 is an image captured by the third illumination device for detecting the third detection area of the MEMS scanning micro-crystal according to the embodiment of the present invention.

Reference numerals are as follows:

100. illumination structure, 110, first illuminator, 120, second illuminator, 130, third illuminator, 200, MEMS scanning microcrystal, 210, first detection zone, 220, second detection zone, 230, third detection zone, 300, camera, 310, telecentric lens, 400, objective table.

Detailed Description

The technical solutions in the embodiments of the present disclosure will be described below clearly and completely with reference to the accompanying drawings in the embodiments of the present disclosure, and it is to be understood that the described embodiments are only some embodiments of the present disclosure, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure.

Specific embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

Fig. 1 shows a MEMS scanning micro-crystal 200 with a size of 15 × 15 μm to be detected according to an embodiment of the present invention. The surface of the MEMS scanning micro-crystal 200 is divided into three detection zones: the first detection area 210 is an oval area (also called a mirror area) located in the middle of the MEMS scanning micro-crystal 200, and the surface of the area is plated with gold and polished, so that the reflectivity of light is high; the second detection area 220 is a coil area which surrounds the first detection area 210 and is in a closed circular ring shape, the surface of the coil area is not pure flat, and the cross section of the coil area is in an uneven wave shape; the remaining area is the third detection zone 230 (also called the silica zone). When detecting surface defects of the MEMS scanning micro-crystal 200, the surface of all three detection areas is inspected.

Currently, the detection of surface defects of the MEMS scanning micro-crystal 200 generally uses a single point light source to irradiate the surface of the MEMS scanning micro-crystal 200. This method can only detect the third detection region 230 (silicon oxide region) on the surface of the MEMS scanning micro-crystal 200, and cannot detect the entire region of the MEMS scanning micro-crystal 200. For process reasons, there will be a certain difference in the gold plating thickness of the second detection area 220 (coil area) on the surface of the MEMS scanning micro-crystal 200. As shown in fig. 2 and 3, under the illumination of the point light source, the coil area images captured have very large gray value differences. In the first detection area 210 (mirror area), the surface of the MEMS scanning micro-crystal 200 is not stained in the mirror area in the image captured by the point light source. Due to the defects, the defects of the whole area of the surface of the MEMS scanning microcrystal 200 can not be automatically detected by using the shot images, but can only be detected by a manual visual inspection method, so that the efficiency is low, the labor cost is high, and the accuracy is poor.

An embodiment of the utility model provides an illumination structure 100 for detecting MEMS scanning micrite surface defect, including setting up at least one following lighting device in MEMS scanning micrite 200 top: a first illumination device 110 and a second illumination device 120.

The first illumination device 110 directly irradiates light onto the surface of the MEMS scanning micro-crystal 200 at a set angle for detecting the quality of the smooth surface, for example, identifying whether the surface has bumps, scratches, cracks, and the like. As shown in fig. 4, in the present embodiment, the first lighting device 110 has a cylindrical shape, and at least a lower end thereof is open. The plurality of light sources are disposed on the inner sidewall of the first lighting device 110 to form a circular ring-shaped arrangement. The light emitted by the circularly arranged light sources directly irradiates the surface of the MEMS scanning micro-crystal 200, and the angle between the light and the surface of the MEMS scanning micro-crystal 200 is smaller than 45 degrees, for example, by adjusting the height position of the first illumination device 110 relative to the surface of the MEMS scanning micro-crystal 200, the first illumination device 110 is close to the surface of the MEMS scanning micro-crystal 200. The closer the first illumination device 110 is to the surface of the MEMS scanning micro-crystal 200, the smaller the angle between the light emitted by the light source and the surface of the MEMS scanning micro-crystal 200, and the better the ability to identify bumps, scratches, and cracks on the surface. The included angle between the light emitted by the light source and the surface of the MEMS scanning micro-crystal 200 can also be adjusted by adjusting the diameter of the circular ring formed by the light source. When the height position of the first illumination device 110 relative to the surface of the MEMS scanning micro-crystal 200 is fixed, the larger the diameter of the circular ring formed by the light source is, the smaller the angle between the light emitted from the light source and the surface of the MEMS scanning micro-crystal 200 is.

The first illumination device 110 can better highlight the surface profile of the MEMS scanning micro-crystal 200 by illuminating light onto the surface of the MEMS scanning micro-crystal 200 with the above-mentioned ring-shaped low-angle light illumination, and identify the bumps, scratches and cracks on the smooth surface of the MEMS scanning micro-crystal 200, so as to be used for detecting whether the first detection area 210 (mirror area) on the surface of the MEMS scanning micro-crystal 200 has defects, such as dirt, scratches, cracks, and the like.

The second illumination device 120 diffusely reflects the light and irradiates the surface of the MEMS scanning micro-crystal 200 to detect whether there is a defect on the curved surface. As shown in fig. 5, in the present embodiment, the second lighting device 120 is an inverted hemispherical shell, and at least the lower end of the hemispherical shell is open. The light source is arranged on the bottom plane of the hemispherical shell. Light emitted by the light source is diffused and reflected on the inner surface of the hemispherical shell with an integral effect, and then irradiates the surface of the MEMS scanning microcrystal 200 from all directions, so that the light irradiates the surface of the MEMS scanning microcrystal 200 uniformly. Therefore, the gray scale of the image shot after the second detection area 220 (coil area) on the surface of the MEMS scanning microcrystal 200 is irradiated is uniform, and whether the second detection area 220 (coil area) has defects or not is convenient to detect. The curvature of the hemispherical curved surface can be changed by adjusting the radius of the hemisphere, so that different diffuse reflection effects can be obtained.

The lighting structure 100 may include only the first lighting device 110, only the second lighting device 120, or both the first lighting device 110 and the second lighting device 120, as desired. When the lighting structure 100 comprises the first lighting device 110 and the second lighting device 120, the second lighting device 120 is disposed above the first lighting device 110, as shown in fig. 4 to 6; wherein both upper and lower ends of the first lighting device 110 are open. The first illumination device 110 and the second illumination device 120 are capable of illuminating the surface of the MEMS scanning micro-crystal 200, respectively. When the surface of the MEMS scanning micro crystal 200 is irradiated with the second illumination device 120, light emitted from the light source in the second illumination device 120 is diffusely reflected, passes through the first illumination device 110 whose upper and lower ends are open, and is irradiated on the surface of the MEMS scanning micro crystal 200.

In one embodiment, the illumination structure 100 further comprises a third illumination device 130, which illuminates the surface of the MEMS scanning micro-crystal 200 with a point light source arranged therein for detecting surface defects of a third detection area 230 (silicon oxide area) of the surface of the MEMS scanning micro-crystal 200.

The lighting devices in the lighting structure 100 may be configured as desired, for example, the lighting structure 100 may include only one of the first lighting device 110, the second lighting device 120, and the third lighting device 130; two of the lighting devices may also be included, for example, a combination of the first lighting device 110 and the third lighting device 130, or a combination of the second lighting device 120 and the third lighting device 130; it is also possible to include all three lighting devices. When the lighting structure 100 is a combination of the third lighting device 130 and one or two other lighting devices, the third lighting device 130 is disposed at the top of all the lighting devices, and the first lighting device 110 or/and the second lighting device 120 located therebelow are open at the upper and lower ends. This allows light from a point source in the third illumination device 130 to pass through the first illumination device 110 or/and the second illumination device 120 located therebelow to impinge on the surface of the MEMS scanning micro-crystal 200.

Fig. 6 shows, and in a particular embodiment, the illumination structure 100, which includes a third illumination device 130, a second illumination device 120, and a first illumination device 110, disposed in this order from top to bottom above the MEMS scanning micro-crystal 200. As shown in fig. 4 and 5, the first illumination device 110 and the second illumination device 120 are both in a structure with both open upper and lower ends, so that light emitted from the third illumination device 130 can pass through the second illumination device 120 and the first illumination device 110 to irradiate on the surface of the MEMS scanning micro-crystal 200; while light emitted by the second illumination device 120 is able to pass through the first illumination device 110 to impinge on the surface of the MEMS scanning micro-crystal 200.

As shown in fig. 6, the present invention also provides a system for detecting surface defects of MEMS scanning micro-crystals, comprising: the illumination structure 100, camera 300 and control module (not shown) for MEMS scanning microcrystalline surface defects described above.

A camera 300 is arranged in the upper part of the illumination structure 100 for taking an image of the surface of the MEMS scanning micro-crystal 200 when illuminated by the illumination structure 100. In this embodiment, the camera 300 is a high resolution camera with a resolution of 3.2 μm. A telecentric lens 310 is provided on the camera 300 to magnify extremely small defects on the surface of the MEMS scanning micro-crystal 200. To facilitate the photographing, the third illuminator 130 may be disposed within the telecentric lens 310. Further, the first illumination device 110 and the second illumination device 120 are both provided in a structure in which the upper and lower ends are open, so that the camera 300 can photograph an image when the surface of the MEMS scanning micro crystal 200 is irradiated by each illumination device. In addition, a stage 400 is provided for positioning the MEMS scanning micro-crystal 200 for supporting and positioning the MEMS scanning micro-crystal 200.

The control module is electrically connected to the illumination structure 100 and the camera 300 for controlling the illumination of the surface of the MEMS scanning micro-crystal 200 by the illumination structure 100. Specifically, the control module is electrically connected to the first illumination device 110, the second illumination device 120, and the third illumination device 130 respectively, and controls the three illumination devices to illuminate the surface of the MEMS scanning micro-crystal 200 in a set sequence and frequency. The control module is also able to control the camera 300 to take an image of the surface of the MEMS scanning micro-crystal 200 when the surface of the MEMS scanning micro-crystal 200 is illuminated by the three illumination means. Fig. 7 shows an image of the surface of the MEMS scanning micro-crystal 200 taken by the camera 300 under the illumination of the first illumination device 110. In contrast to fig. 2 and 3, the first detection area 210 (mirror area) on the surface of the MEMS scanning micro-crystal 200 clearly appears in fig. 7 as a defect (white dot in the first detection area 210) present in the first detection area 210 (mirror area) under illumination by the first illumination device 110. Fig. 8 shows an image of the surface of the MEMS scanning micro-crystal 200 taken by the camera 300 under the illumination of the second illumination device 120 on the surface of the MEMS scanning micro-crystal 200. In comparison with fig. 2 and 3, the second detection area 220 (coil area) on the surface of the MEMS scanning micro-crystal 200 is illuminated by the second illumination device 120, and the state of the second detection area 220 (coil area) is clearly shown in fig. 8. Fig. 9 shows an image of the surface of the MEMS scanning micro-crystal 200 captured by the camera 300 under the illumination of the third illumination device 130 from the surface of the MEMS scanning micro-crystal 200. The state of the third detection zone 230 (coil area) at the surface of the MEMS scanning micro-crystal 200 is clearly presented in fig. 9.

Thereafter, the control module determines whether there is a defect on the surface of the MEMS scanning micro-crystal 200 based on the surface image of the MEMS scanning micro-crystal 200 captured by the camera 300. In a specific embodiment, the captured surface image of the MEMS scanning micro-crystal 200 can be processed by a special algorithm, and then the surface of the MEMS scanning micro-crystal 200 can be determined whether there is a defect according to the set criterion.

In a specific embodiment, an alarm device is also arranged and is electrically connected with the control module; when the control module determines that the surface of the MEMS scanning micro-crystal 200 has defects, the alarm device issues an alarm. The alarm may be an acoustic or optical signal, or a combination of acoustic and optical signals.

The embodiment of the utility model provides an illumination structure and detecting system for detecting microcrystalline surface defect is scanned to MEMS, its improvement mainly lie in that this illumination structure can dispose its contained lighting device's kind according to the needs that detect. And aiming at the structural characteristics of different areas on the surface of the MEMS scanning microcrystal, the corresponding detection areas on the surface of the MEMS scanning microcrystal are irradiated by utilizing the characteristics of the light emitted by the first lighting device and the second lighting device, so that the defects of the detection areas on the surface of the MEMS scanning microcrystal are detected. The detection system utilizes the camera to photograph the irradiated MEMS scanning microcrystal surface, so that clear imaging is carried out on each detection area of the MEMS scanning microcrystal surface, the control module can accurately analyze and judge the defects of the MEMS scanning microcrystal surface according to the shot clear images of the MEMS scanning microcrystal surface, and the detection standards are unified. The system can detect defects of all areas of the surface of the MEMS scanning microcrystal and meet the requirement of high-precision detection. The system adopts the mode that the control module automatically judges the defects to replace manual visual inspection, has high detection efficiency, saves the labor cost, has high detection accuracy and can realize large-batch automatic detection.

In the above description of the present specification, the terms "fixed," "mounted," "connected," or "connected" should be construed broadly unless otherwise explicitly specified or limited. For example, with the term "coupled", it can be fixedly coupled, detachably coupled, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship. Therefore, unless the specification explicitly defines otherwise, those skilled in the art can understand the specific meaning of the above terms in the present invention according to specific situations.

In light of the foregoing description of the present specification, those skilled in the art will also understand that terms used herein, such as "upper," "lower," "front," "rear," "left," "right," "length," "width," "thickness," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," "circumferential," "center," "longitudinal," "lateral," "clockwise," or "counterclockwise," etc., indicate that the terms used herein are based on the orientations and positional relationships illustrated in the drawings of the present specification, and are intended merely for the purpose of facilitating the description and simplifying the description, and do not explicitly or implicitly indicate that the device or element being referred to must have the particular orientation, be constructed and operated in the particular orientation, and therefore the terms used in the orientation or positional relationship should not be understood or interpreted as limiting the scope of the present invention.

In addition, the terms "first" or "second", etc. used in this specification are used to refer to numbers or ordinal numbers only for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present specification, "plurality" means at least two, for example, two, three or more, and the like, unless explicitly specified otherwise.

While various embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous modifications, changes, and substitutions will occur to those skilled in the art without departing from the spirit and scope of the present invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. The following claims are intended to define the scope of the invention and, therefore, to cover module compositions, equivalents, or alternatives falling within the scope of these claims.

Claims (12)

1. An illumination structure (100) for detecting surface defects of MEMS-scanned crystallites, comprising the following illumination means arranged above the MEMS-scanned crystallites (200):

a first illumination device (110) for directly illuminating light rays at a set angle on the surface of the MEMS scanning micro-crystal (200); wherein the light emitted by the first illumination device (110) makes an angle with the surface of the MEMS scanning micro-crystal (200) smaller than 45 °; and

and the second illumination device (120) is used for irradiating the surface of the MEMS scanning microcrystal (200) after the light rays are subjected to diffuse reflection.

2. The lighting structure (100) of claim 1, wherein the light sources in the first lighting device (110) are arranged in a circular ring.

3. The lighting structure (100) of claim 2, wherein the second lighting device (120) is an inverted hemispherical shell.

4. The lighting structure (100) according to claim 3, wherein when the lighting structure (100) comprises the first lighting device (110) and a second lighting device (120), the second lighting device (120) is disposed above the first lighting device (110).

5. Illumination structure (100) according to any of claims 1 to 4, further comprising a third illumination device (130) illuminating the surface of the MEMS scanning micro-crystal (200) by a point light source.

6. The lighting structure (100) according to claim 5, characterized in that, when the lighting structure (100) comprises the third lighting device (130) and the first lighting device (110) or/and the second lighting device (120), the third lighting device (130) is arranged above the first lighting device (110) or/and the second lighting device (120).

7. An inspection system for detecting surface defects of MEMS scanned crystallites, comprising:

the lighting structure (100) according to any one of claims 1-6;

a camera (300) arranged in the upper part of the illumination structure (100) for taking an image of the surface of the MEMS scanning micro-crystal (200) when illuminated by the illumination structure (100);

a control module, electrically connected to the illumination structure (100) and the camera (300), for controlling the illumination of the surface of the MEMS scanning micro-crystal (200) by the illumination structure (100) and the photographing of the surface of the MEMS scanning micro-crystal (200) by the camera (300), and determining whether a defect is present on the surface of the MEMS scanning micro-crystal (200) based on the image of the surface of the MEMS scanning micro-crystal (200) photographed by the camera (300).

8. The inspection system of claim 7, wherein a telecentric lens (310) is disposed on the camera (300).

9. The inspection system of claim 8, wherein the illumination arrangement further comprises a third illumination device (130) illuminating the surface of the MEMS scanning micro-crystal (200) with a point light source, the third illumination device (130) being disposed above the first illumination device (110) or/and the second illumination device (120), the third illumination device (130) being disposed within the telecentric lens (310).

10. The detection system according to claim 7, wherein the camera (300) is a high resolution camera with a resolution of 3.2 μm.

11. A detection system according to any of claims 7 to 10, further comprising an object stage (400) for placing the MEMS scanning micro-crystal (200).

12. The detection system according to any one of claims 7 to 10, further comprising an alarm device electrically connected to the control module; when the control module judges that the surface of the MEMS scanning microcrystal (200) has defects, the alarm device gives an alarm.

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