CN211506023U

CN211506023U - Electrostatic scanning micro-mirror

Info

Publication number: CN211506023U
Application number: CN202020142570.5U
Authority: CN
Inventors: 徐乃涛; 孙其梁; 程进; 李宋泽
Original assignee: Wuxi Micro Vision Sensor Technology Co ltd
Current assignee: Wuxi Micro Vision Sensor Technology Co ltd
Priority date: 2020-01-22
Filing date: 2020-01-22
Publication date: 2020-09-15
Anticipated expiration: 2030-01-22

Abstract

The utility model discloses an electrostatic scanning micro-mirror, which comprises a micro-mirror body at the upper part and a bonding bottom plate at the lower part, wherein the micro-mirror body comprises a frame and a mirror surface, and the back of the frame is fixed on the bonding bottom plate; the upper end and the lower end of the mirror surface are respectively connected with a connecting part and are connected with the frame through a rotating shaft; the outer side of the connecting part is provided with moving teeth, and the inner side of the frame is provided with static teeth at the position opposite to the moving teeth. The utility model discloses an electrostatic scanning micro mirror sets up a dedicated connecting portion between pivot and mirror surface, sets up the broach through the outside at connecting portion, can increase the broach and arrange the region, strengthens the drive power of micro mirror, increases the biggest deflection angle of micro mirror. Meanwhile, the frame is divided into different functional areas by arranging the isolation grooves with different structures on the frame, all the comb tooth components are divided into the driving comb tooth group and the feedback comb tooth group, the mirror surface deflection angle can be monitored in real time while the mirror surface is driven to deflect, and the accuracy of mirror surface deflection angle control is improved.

Description

Electrostatic scanning micro-mirror

Technical Field

The utility model belongs to the technical field of the micro-electro-mechanical system and specifically relates to an electrostatic scanning micro-mirror based on MEMS processing technology preparation.

Background

MEMS refers to Micro-Electro-Mechanical systems (Micro-Electro-Mechanical systems), which is a revolutionary new technology developed on the basis of microelectronic technology, and is a high-tech electromechanical device manufactured by combining technologies such as photolithography, etching, thin film, silicon micromachining, and precision machining. The MEMS device is widely applied to high and new technology industry, and is a key technology related to scientific and technological development, economic prosperity and national defense safety. The scanning micro-mirror is a light reflection type device developed by applying MEMS technology, and drives the mirror surface to deflect under the action of a micro-driving force by connecting a torsion structure of the reflection mirror surface, so that the light beam can be reflected and scanned in one-dimensional or two-dimensional directions. The electrostatic scanning micro-mirror in the prior art comprises a mirror surface and a frame, wherein the mirror surface and the frame are connected together through two rotating shafts. During operation, different voltages are applied between the moving teeth and the static teeth of the micromirror comb tooth group, so that electrostatic force between the comb teeth is changed, the comb teeth are twisted relatively, and the mirror surface is driven to deflect by taking the rotating shaft as an axis. However, the rotating shaft of the scanning micro-mirror cannot be processed too long, which would result in poor rigidity of the rotating shaft and easy breakage of the deflection process. Due to the limitation of the length of the rotating shaft, the number of the comb teeth on the two sides of the rotating shaft is limited, the smaller the number of the comb teeth is, the smaller the electrostatic force is during the work, the smaller the maximum driving force of the whole micromirror is, and the limitation of the maximum deflection angle and the application range of the micromirror is caused. In addition, in the chip packaging stage, the micromirror needs to be picked up and attached to the PCB through a vacuum suction nozzle of a chip mounter, but because the micromirror has a hollow back cavity, a vacuum environment cannot be constructed by a conventional suction nozzle, only a special suction nozzle is used, the test difficulty and the chip cost are increased, and meanwhile, because of the back cavity, the micromirror can only depend on bottom edge dispensing, is unstably fixed on the PCB, can fall off and has low reliability.

SUMMERY OF THE UTILITY MODEL

The applicant aims at the defects that in the prior art, the electrostatic scanning micro mirror is limited by the length of a rotating shaft, the number of comb teeth is limited, the maximum driving force is limited during working, the deflection angle of the micro mirror is influenced, and the micro mirror is difficult to pick up and fix in a packaging stage, and the like.

The utility model discloses the technical scheme who adopts as follows:

an electrostatic scanning micro-mirror comprises a micro-mirror body on the upper part and a bonding bottom plate on the lower part, wherein the micro-mirror body comprises a frame and a mirror surface, and the back of the frame is fixed on the bonding bottom plate; the upper end and the lower end of the mirror surface are respectively connected with a connecting part and are connected with the frame through a rotating shaft; the outer side of the connecting part is provided with moving teeth, and the inner side of the frame is provided with static teeth at the position opposite to the moving teeth.

As a further improvement of the above technical solution:

a metal flat plate electrode is manufactured on the bonding bottom plate and is positioned on one side of the central axis of the mirror surface; through holes are processed on the frame, and external leads are connected with the flat electrodes through metal in the through holes.

And a groove is processed at the position, opposite to the mirror surface, of the middle part of the bonding bottom plate.

The connecting part consists of an upper U-shaped structure and a lower square structure, and the square structures are connected with the mirror surface; one end of the rotating shaft is connected with the inner side of the frame, and the other end of the rotating shaft is connected with the bottom of the U-shaped structure of the connecting part.

The frame is divided into a left driving part, a middle deflection part and a right feedback part by a plurality of isolation grooves, and the rotating shaft is connected with the deflection part; the static teeth of the driving part and the moving teeth of the connecting part form a driving comb group, and the static teeth of the feedback part and the moving teeth of the connecting part form a feedback comb group.

Two semi-surrounded deflection isolation grooves are processed on the frame, a deflection part is arranged in the frame, and the deflection part is connected with the rotating shaft; a feedback isolation groove is processed outside the deflection isolation groove, a feedback part is arranged between the deflection isolation groove and the feedback isolation groove, and a driving part is arranged outside the feedback isolation groove; the end part of the feedback isolation groove divides the comb teeth on the side edge of the connecting part into an upper part and a lower part, the static teeth which are positioned on the feedback part and are far away from the mirror surface and the corresponding moving teeth form a feedback comb teeth group, and the static teeth on the inner side of the driving part and the corresponding moving teeth form a driving comb teeth group.

The surface of the driving part is provided with a first electrode which is used for being connected with an external driving device; the surface of the deflection part is provided with a second electrode; the surface of the feedback part is processed with a third electrode which is used for connecting with an external testing device.

The connecting part is processed into a hollow structure; the comb teeth are trapezoidal or triangular; the mirror surface is square, round or oval.

The electrodes are provided with a large electrode and a small electrode, the small electrode is used for detecting the chip by the probe, and the large electrode is used for finally packaging lead bonding.

The utility model has the advantages as follows:

the utility model discloses an electrostatic scanning micro mirror sets up a dedicated connecting portion between pivot and mirror surface, sets up the broach through the outside at connecting portion, can increase the broach and arrange the region, strengthens the drive power of micro mirror, increases the biggest deflection angle of micro mirror. Meanwhile, the frame is divided into different functional areas by arranging the isolation grooves with different structures on the frame, all the comb tooth components are divided into the driving comb tooth group and the feedback comb tooth group, the mirror surface deflection angle can be monitored in real time while the mirror surface is driven to deflect, and the accuracy of mirror surface deflection angle control is improved.

The utility model discloses a at the fixed bonding bottom plate in the micro mirror back, bonding bottom plate preparation flat electrode can perhaps provide bigger drive power through the deflection angle of flat electrode test mirror surface. Meanwhile, the bottom of the bonding bottom plate is flat and free of hollow, a chip can be picked up through vacuum by using a suction nozzle of a conventional chip mounter, and compared with the method that a micromirror with uneven bottom is directly fixed on a PCB, the bonding bottom plate can be more stably and more conveniently glued and fixed on the PCB.

The utility model discloses a broach adopts trapezoidal or triangle-shaped structure, and the interval between two adjacent broach is littleer, when not increasing the regional length of broach, can set up more broach, compares the rectangle broach among the prior art, can provide bigger drive power.

Drawings

Fig. 1 is a schematic structural diagram of a first embodiment of the present invention.

Fig. 2 is a cross-sectional view of a first embodiment of the present invention.

Fig. 3 is a cross-sectional view of a second embodiment of the present invention.

Fig. 4 is a schematic structural diagram of a third embodiment of the present invention.

Fig. 5 is a schematic structural diagram of a fourth embodiment of the present invention.

Fig. 6 is a schematic view of connecting portions with different shapes in the present invention.

Fig. 7 is a schematic view of comb teeth with different shapes in the present invention.

In the figure: 1. a frame; 1-1, a driving part; 1-2, a deflection section; 1-3, a feedback part; 2. a mirror surface; 3. a rotating shaft; 4. a connecting portion; 5. an isolation trench; 6. driving the comb teeth group; 7. feeding back the comb teeth group; 8. a first electrode; 9. a second electrode; 10. a third electrode; 11. a deflection isolation tank; 12. a feedback isolation tank; 13. bonding the base plate; 14. a through hole; 15. a plate electrode.

Detailed Description

The following describes embodiments of the present invention with reference to the drawings.

The first embodiment is as follows:

as shown in fig. 1 and 2, the utility model discloses an electrostatic scanning micro mirror includes the micro mirror body on upper portion and the bonding bottom plate 13 of below, and the micro mirror body includes frame 1 and mirror surface 2, and the frame 1 back is fixed on bonding bottom plate 13, and bonding bottom plate 13 bottom surface is level and smooth, because bonding bottom plate 13 bottom is level and smooth, compares directly with the fixed PCB of micro mirror on, bonding bottom plate 13 can be more stable, more convenient rubber coating fix on PCB. The bonding base plate 13 is made of glass, silicon, metal and other materials, and the frame 1 and the mirror face 2 are made of silicon materials or metal alloys. The frame 1 is divided into a left driving part 1-1, a middle deflection part 1-2 and a right feedback part 1-3 from left to right, and the three parts are electrically isolated by an isolation groove 5 and are not conducted with each other. The shape of the mirror 2 is preferably square, circular or elliptical. The upper end and the lower end of the mirror surface 2 are respectively connected with a connecting part 4, and the connecting part 4 is connected with the deflection part 1-2 through a rotating shaft 3. The utility model discloses a scanning micro mirror during operation, the connecting portion 4 at mirror surface 2 and both ends use pivot 3 to take place to deflect as the axis jointly. The integral structure of the connecting part 4 is a U-shaped structure on the upper part and a square structure on the lower part, the square structure is connected with the mirror surface 2, and the width of the square structure is larger than that of the rotating shaft 3. One end of the rotating shaft 3 is connected with the inner side of the deflection part 1-2, and the other end is connected with the bottom of the U-shaped structure of the connecting part 4. The outer side of the connecting part 4 is provided with moving teeth.

As shown in fig. 1, the inner side of the left driving portion 1-1 is provided with static teeth at a position opposite to the moving teeth of the connecting portion 4, and the static teeth and the moving teeth of the connecting portion 4 form a driving comb teeth group 6. The surface of the driving part 1-1 is also processed with a first electrode 8 for connecting with an external driving device, the surface of the deflection part 1-2 is processed with a second electrode 9, the second electrode 9 is preferably a grounding electrode, and by applying different voltages between the first electrode 8 and the second electrode 9, electrostatic force can be generated between the static teeth and the moving teeth of the driving comb teeth group 6 to drive the mirror surface 2 to deflect. The utility model discloses all electrodes all have a big one little bipolar electrode, and the microelectrode is used for the probe to detect the chip, and the microelectrode is used for final encapsulation lead bonding, prevents effectively that the single electrode from being pricked many times by the probe and survey the back and damage, and the unusual of the unable routing that leads to.

The inner side of the right feedback part 1-3 is also provided with static teeth at the position opposite to the movable teeth of the connecting part 4, and the static teeth and the movable teeth corresponding to the connecting part 4 form a feedback comb tooth group 7 together. The surface of the feedback part 1-3 is also provided with a third electrode 10 which is used for being connected with an external testing device and measuring the capacitance of the feedback comb tooth group 7 when the mirror surface 2 deflects, so as to obtain the deflection angle of the mirror surface 2.

When the electrostatic scanning micro-mirror of the embodiment is in operation, a voltage is applied between the first electrode 8 and the second electrode 9 to provide a driving signal to the driving comb-teeth group 6, and under the action of electrostatic force between the moving teeth and the static teeth, the mirror surface 2 and the connecting part 4 jointly deflect by taking the rotating shaft 3 as an axis. Meanwhile, a certain angle is formed between the moving teeth and the static teeth of the feedback comb teeth group 7, a certain capacitance value is obtained, and the rotation angle of the mirror surface 2 can be calculated by measuring the capacitance of the feedback comb teeth group 7 through the third electrode 10.

In this embodiment, since the length of the connecting portion 4 is greater than the length of the rotating shaft 3, compared with the scanning micromirror in the prior art, under the condition that the length of the rotating shaft 3 is not changed, the comb tooth arrangement area can be increased through the connecting portion 4, more comb teeth are processed, the driving force of the whole scanning micromirror is further improved, and the maximum deflection angle of the mirror surface 2 is increased. Meanwhile, because the comb teeth of the feedback comb tooth group 7 are also increased, the feedback capacitance signal is larger, the influence of environmental noise on the feedback capacitance value can be effectively reduced, and the accuracy of mirror deflection angle measurement is improved.

Of course, in the present invention, the whole frame 1 can be divided into the driving portion 1-1 and the deflecting portion 1-2 by the isolation groove 5, that is, the driving portion 1-1 is disposed on both sides of the deflecting portion 1-2 in fig. 1, so that all the comb teeth form the driving comb teeth group 6, and the driving force of the micromirror is further improved. The measurement of the deflection angle of the mirror surface can be monitored by an external measuring device.

As shown in fig. 2, the flat plate electrode 15 made of metal material is fabricated on the bonding bottom plate 13 in the area below the mirror surface 2, and the flat plate electrode 15 is located on one side of the central axis of the mirror surface 2. Meanwhile, a through hole 14 is formed in the frame 1, and an external lead is connected to the flat electrode 15 through a metal in the through hole. When the micromirror operates, the distance between the mirror surface 2 and the plate electrode 15 changes due to the vibration of the mirror surface 2, causing a change in capacitance between the mirror surface 2 and the plate electrode 15. The metal lead is connected with an external test system, so that the capacitance change between the polar plates caused by the deflection of the detection mirror surface 2 can be detected, and the deflection angle of the mirror surface 2 can be calculated. Of course, it is also possible to apply a driving voltage to the plate electrode 15 and to apply a driving force to the mirror 2 by an electrostatic force with the mirror 2.

Example two:

as shown in fig. 3, the middle of the substrate 13 is processed to be a groove, which can provide enough deflection space for the edge of the mirror 2 when the mirror 2 is deflected, prevent the edge of the mirror 2 from bottoming out, and increase the maximum deflection angle of the whole micromirror.

Example three:

as shown in fig. 4, the connecting portion 4 and the rotating shaft 3 of the present embodiment are the same as those of the first embodiment. On the frame 1, the deflection part 1-2 is separated from other parts by two U-shaped deflection separation grooves 11, the deflection part 1-2 is connected with the rotating shaft 3, and a second electrode 9 is processed. A feedback isolation groove 12 is processed outside the deflection isolation groove 11, a feedback part 1-3 is arranged between the feedback isolation groove 12 and the deflection isolation groove 11, a third electrode 10 is processed on the feedback part 1-3, and the end part of the feedback isolation groove 12 divides the comb teeth on the side edge of the connecting part 4 into an upper part and a lower part. Wherein, the static teeth and the corresponding moving teeth which are positioned on the feedback part 1-3 and far away from the mirror surface 2 form a feedback comb teeth group 7, and the static teeth and the corresponding moving teeth on the inner side of the driving part 1-1 form a driving comb teeth group 6.

The number of the driving teeth and the number of the feedback teeth can be reasonably distributed through the deflection isolation groove 11 and the feedback isolation groove 12 with special structures. In actual design and manufacturing process, can set up the feedback isolation groove 12 of suitable position according to the size of the required drive power of micro mirror to and the size of required feedback capacitance value, and then obtain the drive tooth and the feedback tooth of reasonable quantity, satisfy the demand in two aspects of drive power and feedback precision simultaneously.

Example four:

as shown in fig. 5, in the present embodiment, the deflection separating grooves 11 are also used to separate the deflection units 1-2 from other parts, and the comb teeth at the upper and lower connecting portions 4 are all used to form the driving comb teeth group 6. Feedback isolation grooves 12 are processed on the other two opposite side frames 1 of the mirror surface 2 without the connecting part 4 to isolate the feedback parts 1-3 from the driving parts 1-1, and paired static teeth and moving teeth are respectively processed in the areas of the inner sides of the feedback parts 1-3 opposite to the mirror surface 2 to jointly form a feedback comb tooth group 7.

When the scanning micro-mirror works, the mirror surface 2 is driven to deflect by the electrostatic force between the comb teeth of the driving comb tooth group 6, when the mirror surface 2 deflects, a certain angle is formed between the movable teeth and the static teeth of the feedback comb tooth group 7, a certain capacitance value is obtained, and the rotating angle of the mirror surface 2 can be calculated by measuring the capacitance of the feedback comb tooth group 7 through the third electrode 10.

Of course, the feedback comb teeth group 7 may be formed only on one side of the mirror surface 2. With the structure of the present embodiment, the driving comb-tooth group 6 having the largest number of comb teeth can be obtained, and a larger driving force can be obtained. Meanwhile, the positions of the two sides of the mirror surface 2 are utilized to form a feedback comb tooth group 7 for feeding back the deflection angle of the mirror surface 2 in real time.

Example five:

fig. 6 shows four different configurations of the connecting portion 4. Fig. 6a shows the basic structure, the connecting part 4 being of solid construction. Fig. 6b to 6d are all hollow structures, and through holes with different shapes are processed on the connecting part 4. The connecting part 4 is processed into a hollow structure, so that the whole weight of the micromirror can be reduced, and the heat dissipation effect of the micromirror can be improved.

Example six:

fig. 7 shows three different configurations of comb teeth. Fig. 7a shows the basic structure, the comb teeth being rectangular. The comb teeth of fig. 7b are trapezoidal and the comb teeth of fig. 7c are triangular. Especially, the comb teeth are designed to be triangular, compared with the rectangular comb teeth, the distance between two adjacent comb teeth is smaller, and more triangular comb teeth can be arranged in the same length. The more the comb teeth, the greater the driving force can be provided. Through the special shape broach of this embodiment, especially triangle-shaped broach, when not increasing the regional length of broach, can set up more broach, and then improve the drive power of micro mirror.

The above description is illustrative of the present invention and is not intended to limit the present invention, and the present invention may be modified in any manner without departing from the spirit of the present invention.

Claims

1. An electrostatic scanning micromirror, comprising: the micro-mirror comprises a micro-mirror body on the upper part and a bonding bottom plate (13) on the lower part, wherein the micro-mirror body comprises a frame (1) and a mirror surface (2), and the back of the frame (1) is fixed on the bonding bottom plate (13); the upper end and the lower end of the mirror surface (2) are respectively connected with a connecting part (4) and are connected with the frame (1) through a rotating shaft (3); the outer side of the connecting part (4) is provided with moving teeth, and the inner side of the frame (1) is provided with static teeth at the position opposite to the moving teeth.

2. An electrostatic scanning micromirror as claimed in claim 1, wherein: a metal flat plate electrode (15) is manufactured on the bonding bottom plate (13), and the flat plate electrode (15) is positioned on one side of the central axis of the mirror surface (2); through holes (14) are processed on the frame (1), and external leads are connected with the flat electrodes (15) through metal in the through holes.

3. An electrostatic scanning micromirror as claimed in claim 1, wherein: and a groove is processed at the position opposite to the mirror surface (2) in the middle of the bonding bottom plate (13).

4. An electrostatic scanning micromirror as claimed in claim 1, wherein: the connecting part (4) consists of an upper U-shaped structure and a lower square structure, and the square structure is connected with the mirror surface (2); one end of the rotating shaft (3) is connected with the inner side of the frame (1), and the other end of the rotating shaft is connected with the bottom of the U-shaped structure of the connecting part (4).

5. An electrostatic scanning micromirror as claimed in claim 1, wherein: the frame (1) is divided into a left driving part (1-1), a middle deflection part (1-2) and a right feedback part (1-3) by a plurality of isolation grooves (5), and the rotating shaft (3) is connected with the deflection part (1-2); the static teeth of the driving part (1-1) and the moving teeth of the connecting part (4) form a driving comb tooth group (6), and the static teeth of the feedback part (1-3) and the moving teeth of the connecting part (4) form a feedback comb tooth group (7).

6. An electrostatic scanning micromirror as claimed in claim 1, wherein: two semi-surrounded deflection isolation grooves (11) are processed on the frame (1), a deflection part (1-2) is arranged inside the deflection isolation grooves, and the deflection part (1-2) is connected with the rotating shaft (3); a feedback isolation groove (12) is processed outside the deflection isolation groove (11), a feedback part (1-3) is arranged between the deflection isolation groove (11) and the feedback isolation groove (12), and a driving part (1-1) is arranged outside the feedback isolation groove (12); the comb teeth on the side of the connecting part (4) are divided into an upper part and a lower part by the end part of the feedback isolation groove (12), static teeth which are positioned on the feedback part (1-3) and far away from the mirror surface (2) and corresponding moving teeth form a feedback comb teeth group (7), and static teeth on the inner side of the driving part (1-1) and corresponding moving teeth form a driving comb teeth group (6).

7. An electrostatic scanning micromirror as claimed in claim 5 or 6, characterized in that: the surface of the driving part (1-1) is provided with a first electrode (8) for connecting with an external driving device; a second electrode (9) is processed on the surface of the deflection part (1-2); the surface of the feedback part (1-3) is processed with a third electrode (10) which is used for connecting with an external testing device.

8. An electrostatic scanning micromirror as claimed in claim 1, wherein: the connecting part (4) is processed into a hollow structure; the movable teeth and the static teeth are trapezoidal or triangular; the mirror surface (2) is square, round or oval.

9. An electrostatic scanning micromirror as claimed in claim 7, wherein: the first electrode (8), the second electrode (9) and the third electrode (10) are respectively provided with a large electrode and a small electrode, the small electrodes are used for detecting a chip by a probe, and the large electrodes are used for finally packaging lead bonding.