CN117604448A - High-stability high-coaxiality mechanical rotary light cone coating device and coating method - Google Patents

Abstract

The invention relates to a mechanical rotating light cone coating device and coating method with high stability and high coaxiality. The device includes a rotating base, a mask plate and a sample chamber; the lower end surface of the sample chamber passes through the interior of the rotating base. The lower end surface of the sample chamber is fixed with screws, and the size of the lower end surface of the sample chamber is smaller than the inner size of the rotating base. The upper end surface of the sample chamber and the platform are fixed with screws; the outer lower end surface of the rotating base is fixed with the mask and drives the mask. The diaphragm rotates. The mechanical rotating light cone coating device with high stability and high coaxiality according to the invention cooperates with the snail-shaped mask plate designed according to the light cone vignetting transmittance, so that the film thickness can be achieved on the same substrate through one coating process. The effects of different gradient distributions can achieve the purpose of improving uniform transmittance.

Description

High-stability, high-coaxiality mechanical rotating light cone coating device and coating method

Technical Field

The invention relates to the field of coating fixtures, and in particular to a mechanical rotating light cone coating device and a coating method with high stability and high coaxiality.

Background Art

Fiber optic cones are widely used in the coupling of charge coupled devices (CCDs), image intensifiers and photomultiplier tubes in the fields of national defense, scientific research, criminal investigation, aerospace, and medical treatment, and are also used in radiographic imaging, new fingerprint recognition, high-definition television imaging, and advanced office equipment imaging. In recent years, with the rapid development of image digital processing technology, the acquisition, storage, and transmission of high-fidelity images have become very convenient, and have become an important symbol of human beings entering the digital age. However, in the process of war, scientific research, production, and medical treatment, people often need to observe, analyze, and process weak images and events that are invisible to the naked eye, such as monitoring and observation at night without light; imaging research of objects that emit radiation; tracking and identification of high-speed aircraft, etc. In these cases, the brightness of the image is usually only ^10-3 to ^10-4 candela, or even lower. Therefore, the image must be enhanced before observation, processing, and analysis. Conventional image digital processing technology can no longer meet this requirement. Using fiber optic cones to couple CCDs, photomultiplier tubes, and image intensifiers is the best choice to achieve digital low-light imaging and reduce the size of the device.

The uniformity of light transmission of the light cone transmittance is closely related to the detection sensitivity of the optoelectronic coupling device. The light cone is obtained by melting and pressing tens of millions or even hundreds of millions of micron-sized fibers and then deforming them at high temperature. The finished product is shown in Figure 1. The optical fiber in the center area of the light cone is stretched axially to form a straight tapered optical fiber; the optical fiber away from the axis not only produces axial elongation but also radial displacement to form a curved tapered optical fiber. It is precisely because of the inconsistent degree of deformation of the optical fiber in the center and edge areas that the transmittance distribution of the output end face of the light cone is different, that is, the trend of gradually decreasing from the center to the edge as shown in Figures 2A and 2B. This non-uniformity of light transmission will deteriorate the detection sensitivity, detection accuracy and coupling resolution of the light cone coupling optoelectronic device. Plating a homogenizing film on the surface of the light cone is an effective method to improve the non-uniformity of the light cone transmittance. The traditional method of plating a homogenizing film mostly uses a step coating method to reduce the transmittance in the central area to the transmittance in the edge area. The film thickness gradually decreases from the center to the edge. This method will cause the light cone transmittance to appear in a step-like distribution (see Figure 2A and Figure 2B). The coating process is relatively cumbersome and requires repeated plating. It is costly and takes a lot of time and energy. The yield is not high and it is difficult to meet the purpose of improving the uniformity of light transmission. Therefore, a new coating method is needed to prepare a high-uniformity film in combination with a snail-shaped mask designed according to the vignetting transmittance of the light cone, fully improve the non-uniformity of the light cone transmittance, and improve the detection sensitivity of the optoelectronic coupling device, which is of great significance to the fields of national defense and scientific research.

Summary of the invention

In view of this, the main purpose of the present invention is to provide a high-stability, high-coaxiality mechanical rotating light cone coating device and coating method. The technical problem to be solved is that the snail-shaped mask plate designed according to the light cone vignetting transmittance can achieve the effect of different gradual distribution of film thickness on the same substrate through a single coating process, thereby achieving the purpose of improving uniform transmittance.

The purpose of the present invention and the technical problem to be solved are achieved by adopting the following technical solutions. The present invention proposes a high-stability, high-coaxiality mechanical rotating light cone coating device, comprising a rotating base, a mask and a sample chamber;

The lower end surface of the sample bin is fixed to the interior of the rotating base by screws, and the size of the lower end surface of the sample bin is smaller than the size of the interior of the rotating base. The upper end surface of the sample bin is fixed to the platform by screws; the outer lower end surface of the rotating base is fixed to the mask plate and drives the mask plate to rotate.

Furthermore, in the aforementioned high-stability, high-coaxiality mechanical rotating light cone coating device, a sample is placed inside the sample chamber.

Furthermore, in the aforementioned high-stability, high-coaxiality mechanical rotating light cone coating device, a rubber pad is provided in the gap between the interior of the sample chamber and the sample.

Furthermore, in the aforementioned high-stability, high-coaxiality mechanical rotating light cone coating device, one end of the platform is fixed to the motor by a screw.

Furthermore, the aforementioned high-stability, high-coaxiality mechanical rotating light cone coating device also includes a motor, the motor includes a motor shaft, the motor shaft is placed longitudinally, and a small gear is installed at the tail of the motor shaft.

Furthermore, in the aforementioned high-stability, high-coaxiality mechanical rotating light cone coating device, the pinion gear is connected to the large gear to form a transmission device, and the pinion gear drives the large gear to rotate; the speed ratio of the pinion gear to the large gear is (4-6):1.

Furthermore, in the aforementioned high-stability, high-coaxiality mechanical rotating light cone coating device, the large gear is fixed to the outer upper end of the rotating base by screws, and the two are of the same size, and the large gear drives the rotating base to rotate.

Furthermore, in the aforementioned high-stability, high-coaxiality mechanical rotating light cone coating device, the rotating base is a bearing structure composed of two concentric rings, which includes a non-rotating internal structure and a rotating external structure connected by steel balls; its internal structure is fixed to the sample chamber, the upper end face of the external structure is fixed to the large gear, and the lower end face of the external structure is fixed to the mask plate and drives the mask plate to rotate.

Furthermore, in the aforementioned high-stability, high-coaxiality mechanical rotating light cone coating device, a gap of 1-2 mm is left between the mask and the rotating base.

The purpose of the present invention and the solution to its technical problems can also be achieved by adopting the following technical solutions. A light cone coating method proposed by the present invention comprises the following steps:

1) Place the assembled high-stability, high-coaxiality mechanical rotating light cone coating device into the chamber of the coating equipment;

2) Turn on the power supply and adjust the rotation speed of the mechanical rotating light cone coating device with high stability and high coaxiality;

3) Close the chamber and start coating.

Furthermore, in the aforementioned light cone coating method, in step 1), the coating equipment is a vacuum evaporation coating machine, an electron beam evaporation coating machine or a magnetron sputtering coating machine.

Furthermore, in the aforementioned light cone coating method, in step 2), the rotation speed of the high-stability, high-coaxiality mechanical rotating light cone coating device is adjusted to 10 rpm-15 rpm.

Furthermore, in the aforementioned light cone coating method, in step 3), the closing of the chamber and starting coating specifically includes:

a. After closing the chamber of the coating equipment, turn on the mechanical pump to pre-vacuum. When the vacuum degree is less than or equal to 10Pa, turn off the mechanical pump, open the solenoid valve, and turn on the molecular pump.

b. When the vacuum degree is less than or equal to 2×10 ^-4 , turn on the gas flow meter and adjust the gas flow of argon and oxygen to 20-30 sccm. Next, adjust the pressure in the chamber to 0.8-1.0 Pa through the G valve;

c. Turn on the sputtering power switch and adjust the power to 30-50W to start pre-sputtering. After sputtering for 3-5 minutes, open the baffle valve and adjust the power to 60-80W to start formal sputtering. The sputtering time is 3-5 minutes;

d. After sputtering is completed, close the flapper valve, turn off the power switch, turn the gas flow meter knob to 0, close the solenoid valve, turn off the molecular pump, and open the valve connected to the air to balance the internal and external atmospheric pressure of the chamber;

e. Open the chamber of the coating equipment, take out the high-stability, high-coaxiality mechanical rotating light cone coating device, and the coating is completed.

By means of the above technical solution, the high stability and high coaxiality mechanical rotating light cone coating device and coating method of the present invention have at least the following advantages:

The high-stability, high-coaxiality mechanical rotating light cone coating device of the present invention can achieve the effect of different gradual distribution of film thickness on the same substrate through a single coating process according to the snail-shaped mask designed according to the light cone vignetting transmittance, and the non-uniformity reaches less than 2.5%, thereby achieving the purpose of improving uniform transmittance;

The high-stability and high-coaxiality mechanical rotating light cone coating device of the present invention can achieve a coating stability of more than 99.5%.

The thin film plated by the high-stability and high-coaxiality mechanical rotating light cone coating device of the present invention has a high coaxiality at the exact center of the light cone sample, and the coaxiality can be better than 0.05.

The high-stability, high-coaxiality mechanical rotating light cone coating device of the present invention can solve the problem of uneven transmittance at the output end of the light cone, so that the light cone can achieve better effect when coupled with a CCD, a photomultiplier tube and an image intensifier.

The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a finished light cone diagram in the prior art;

FIG2A is one of the transmittance diagrams of the light cone;

FIG2B is a second transmittance diagram of the light cone;

FIG3 is a diagram of a snail-shaped mask in the prior art;

FIG4 is an overall plan view of a high-stability, high-coaxiality mechanical rotating light cone coating device of the present invention;

FIG5 is an overall stereogram of the mechanical rotating light cone coating device with high stability and high coaxiality of the present invention;

FIG6 is a three-dimensional view of the mechanical rotating light cone coating device with high stability and high coaxiality of the present invention without a protective shell;

FIG7 is a partial cross-sectional perspective view of the mechanical rotating light cone coating device with high stability and high coaxiality of the present invention;

FIG8 is a schematic diagram of the structure of a rotating base of a mechanical rotating light cone coating device with high stability and high coaxiality according to the present invention;

FIG9 is a graph showing the relative transmittance of the light cone of Comparative Example 1 along the diameter direction;

FIG10 is a graph showing the relative transmittance of the light cone along the diameter direction according to Example 1 of the present invention;

FIG11 is a graph showing the relative transmittance of the light cone along the diameter direction according to Example 2 of the present invention;

FIG12 is a graph showing the relative transmittance of the light cone along the diameter direction according to Example 3 of the present invention;

FIG13 is a graph showing the relative transmittance of the light cone along the diameter direction according to Example 4 of the present invention;

Among them: 1. Protective shell; 2. Motor; 3. Small gear; 4. Large gear; 5. Rotating base; 6. Mask; 7. Sample chamber; 8. Platform; 9. Sample.

DETAILED DESCRIPTION

In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation, features and effects of the mechanical rotating light cone coating device and coating method with high stability and high coaxiality proposed by the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. In addition, specific features or characteristics in one or more embodiments may be combined in any suitable form.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" in the specification and claims of the present invention and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

In the description of the embodiments of the present invention, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present invention, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

In the description of the embodiments of the present invention, the term "and/or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and/or B may represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character "/" in this article generally indicates that the associated objects before and after are in an "or" relationship.

In the description of the embodiments of the present invention, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

In the description of the embodiments of the present invention, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the embodiments of the present invention.

In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

As shown in Figures 4-7, the present invention provides a high-stability, high-coaxial mechanical rotating light cone coating device, including a protective shell 1, a motor 2, a small gear 3, a large gear 4, a rotating base 5, a mask 6, a sample chamber 7, a platform 8, and a sample 9 fixed by screws. The protective shell 1 is fixedly connected to the platform 8, so that the entire device is in a regular shape (it is a rectangular parallelepiped with a length of 173mm, a width of 136mm, and a height of 115mm), which is convenient for placement in the chamber. Among them, the platform 8 is a rectangular metal plate with a thickness of 3mm, so that the size can be reduced as much as possible under the premise of ensuring that the motor, sample chamber and other components can bear the load; as shown in Figure 8, the rotating base 5 is a bearing structure composed of two concentric rings, which includes a non-rotating internal structure and a rotating external structure connected by steel balls, and its internal structure is fixed to the sample chamber 7, the upper end face of its external structure is fixed to the large gear 4, and the lower end face of its external structure is fixed to the mask 6, so that the mask can be rotated and the sample chamber does not rotate. Specifically, the rotating base 5 is a high-precision bearing, the gap inside the bearing is very small, and the distance between the two is filled with steel balls, which is very stable and will not shake, thereby ensuring high coaxiality. Since the rotating base 5 is a three-dimensional structure and is located between the sample chamber 7 and the mask plate 6, according to the direction of placing the high-stability, high-coaxiality mechanical rotating light cone coating device in the coating equipment, the sample chamber 7 is fixed on the upper part of the rotating base 5, and the mask plate 6 is fixed on the lower part of the rotating base 5. The sample 9 is a light cone, and there are no requirements for its size and performance. Light cones of different sizes can be placed by changing the size of the sample chamber.

The sample 9 is placed in the sample chamber 7. The sample chamber 7 is 4mm higher than the sample and has a built-in rubber pad to prevent the end face of the sample 9 from being damaged when the rotating light cone coating device is disassembled upside down. Specifically, the rubber pad is located between the large end face of the light cone and the sample chamber 7. This arrangement can prevent the large end face of the light cone from directly contacting the sample chamber 7. The sample chamber 7 is made of polytetrafluoroethylene. The reason for choosing polytetrafluoroethylene is firstly because it is light in weight and can reduce the overall weight of the device; secondly, it is because it can withstand higher temperatures than ordinary plastics. The upper end face of the sample chamber 7 is fixed to the platform 8 by screws, and its lower end face is fixed to the upper end face of the internal structure of the rotating base 5 by screws. The sample chamber 7 is a cylindrical groove with a diameter of 48mm and a depth of 45mm. One end of the platform 8 is fixed to the motor 2 by screws to ensure that the mask rotates without interference while ensuring the coating effect.

A small-diameter pinion 3 is installed at the tail end of the shaft of the motor 2. The rotation of the motor 2 drives the pinion 3 to rotate. This arrangement is to ensure that the rotation of the mask is not disturbed while ensuring the coating effect.

The pinion 3 is meshed with the large diameter and hollow large gear 4, and the rotation of the pinion 3 drives the large gear 4 to rotate. In specific implementation, the diameter of the large gear 4 needs to be equal to the diameter of the outer side of the bearing. Considering that the sample chamber 7 needs to be placed in the middle of the large gear 4, the large gear 4 is set to be hollow. Among them, the diameter of the large gear 4 is consistent with the size of the rotating base, and the speed ratio of the pinion 3 and the large gear 4 is (4-6): 1, preferably 5: 1. After optimization, the uniformity of film formation is good; according to the speed ratio, the pinion 3 with a suitable diameter is selected. Too fast or too slow speed is likely to cause poor uniformity of film formation and stains on the surface of the film layer. The speed ratio design between the large and small gears is intended to control the speed of the bottom mask and improve the uniformity of the coating thickness. Combined with the position of the pinion and the speed ratio, the diameter of the pinion 3 is designed to be 3-4cm. At the same time, the mechanical rotating light cone coating device with high stability and high coaxiality can use large and small gears for transmission in a limited space, so that the transmission efficiency is high.

The motor 2 drives the small gear 3 to rotate, the small gear 3 drives the large gear 4 to rotate, the large gear 4 drives the outer part of the bearing to rotate, and the outer part of the bearing drives the mask to rotate, so that the sample does not rotate but the mask rotates by itself.

The large gear 4 is fixed to the upper end of the outer portion of the rotating base 5 by screws. The rotation of the large gear 4 drives the rotating base 5 to rotate. A 1-2 mm gap is left between the large gear 4 and the sample chamber 7 so that the large gear 4 will not be affected by the sample chamber 7 when rotating. If the gap is less than 1 mm, the gap is too small and the two may rub against each other during rotation; if the gap is greater than 2 mm, the gap is too large and the thickness of the large gear is too small, which is not conducive to its fixation.

The outer lower end surface of the rotating base 5 is fixed to the mask 6 by screws, and the outer part of the rotating base 5 drives the mask 6 to rotate. The size of the mask 6 is equal to the outer size of the rotating base 5, and the gap between the two is 2mm, so that the mask 6 rotates without interference while ensuring the coating effect. Specifically, the mask 6 is a hollowed-out spiral copper plate with a thickness of 0.5-2mm and a diameter of 80-200mm. The hollowed-out middle part of the spiral copper plate has a larger opening and a smaller opening at the edge, that is, the middle exposure time is long and the edge exposure time is short during coating, so that a gradient film with a thick middle film layer and a thin edge film layer can be achieved. The thinner the copper plate is, the better it is under the premise of ensuring that the mask plate is not deformed, so that the sputtering material can be better attached to the sample; it has been found through testing that a mask plate with a thickness of less than 0.5mm is easy to deform. Considering that the mask 6 is fixed to the rotating base by screws, the diameter of the mask 6 is the same as the outer size of the rotating base to facilitate fixation. If the diameter of the mask plate is less than 80 mm, it cannot be fixed on the rotating base. If the diameter of the mask plate is greater than 200 mm, it is inconvenient to operate.

The high-stability, high-coaxiality mechanical rotating light cone coating device can make the mask plate 6 rotate relative to the sample chamber 7. Combined with the existing snail-shaped mask plate shown in Figure 3, during the rotation process, the central area is exposed for a long time and the edge area is exposed for a short time. A small peak film layer with a thicker film layer in the central area and a thinner film layer in the edge area can be obtained, so that the transmittance of the central area and the edge area is similar, thereby achieving the effect of consistent overall transmittance at the light cone output end.

The "high stability" in the above-mentioned "mechanical rotating light cone coating device with high stability and high coaxiality" refers to the good coating repeatability, which can reach more than 99.5%, and the "high coaxiality" in the above-mentioned "mechanical rotating light cone coating device with high stability and high coaxiality" refers to the high coaxiality of the coating film layer and the light cone, which is better than 0.05mm.

High coaxiality and high stability are the indispensable advantages of the mechanical rotating light cone coating device. It is precisely because of its high coaxiality and high stability that the thickness of the coated film layer has good repeatability and can ensure that the thickness of the film layer gradually becomes thinner along the radial direction with the center of the geometric position of the substrate as the midpoint, thereby forming a suppressive effect on the transmittance that gradually weakens along the radial direction of the midpoint. Since the light transmittance of the light cone substrate itself gradually decreases along the radial direction at the midpoint, combined with the trend of the film layer to reduce the light transmittance, the overall transmittance of the optical fiber cone is homogenized, and the transmittance in the middle decreases more obviously, and the transmittance decreases less towards the edge. The use of a snail-shaped mask plate realizes the coating of a film layer with a gradually varying thickness along the radial direction at the midpoint. The size of the snail-shaped mask plate determines the central transmittance and non-uniformity results.

The present invention also provides a light cone coating method, comprising the following steps:

1) Place the assembled high-stability, high-coaxiality mechanical rotating light cone coating device into the chamber of the coating equipment; the coating equipment may be a vacuum evaporation coating machine, an electron beam evaporation coating machine, or a magnetron sputtering coating machine. Since the high-stability, high-coaxiality mechanical rotating light cone coating device described in the present invention is highly compatible, the coating equipment may specifically be a magnetron sputtering coating machine; the chamber has good sealing properties and can be used to place samples or devices to be coated; if the mask plate is installed first, the sample cannot be installed, so if the device needs to be used, the sample must be installed first and then the mask plate;

2) Turn on the power supply and adjust the speed of the mechanical rotating light cone coating device with high stability and high coaxiality; since the motor speed of the mechanical rotating light cone coating device with high stability and high coaxiality is adjustable, the motor speed can be adjusted to 10-15rpm by turning the button;

3) Closing the chamber and starting the coating. Closing the chamber and starting the coating specifically includes the following steps:

a. After closing the chamber of the coating equipment, turn on the mechanical pump to pre-vacuum. When the vacuum degree is less than or equal to 10Pa, turn off the mechanical pump, open the solenoid valve, and turn on the molecular pump.

b. When the vacuum degree is less than or equal to 2×10 ^-4 , turn on the gas flowmeter and adjust the gas flow of argon and oxygen to 20-30sccm. Next, adjust the pressure in the chamber to 0.8-1.0Pa through the G valve. The vacuum degree is less than or equal to 2×10 ^-4 to meet the coating requirements. The lower the vacuum degree, the fewer impurities in the chamber. The lower the pressure in the chamber, that is, the working pressure, the higher the quality of the film layer, but the speed will be slower. Therefore, 0.8-1.0Pa is selected as the working pressure.

c. Turn on the sputtering power switch and adjust the power to 30-50W to start pre-sputtering. After sputtering for 3-5 minutes, open the baffle valve and adjust the power to 60-80W to start formal sputtering. The sputtering time is 3-5 minutes. The function of pre-sputtering is first to preheat the machine. It is not advisable to use high power when starting the machine. Secondly, it sputters away impurities on the surface of the target material.

d. After sputtering is completed, close the flapper valve, turn off the power switch, turn the gas flow meter knob to 0, close the solenoid valve, turn off the molecular pump, and open the valve connected to the air to balance the internal and external atmospheric pressure of the chamber;

e. Open the chamber of the coating equipment, take out the high-stability, high-coaxiality mechanical rotating light cone coating device, and the coating is completed.

The present invention is further described below in conjunction with specific embodiments.

The central transmittance of the following Examples 1-4 and Comparative Example 1 is obtained by a transmittance tester (i.e., a device for detecting the visible light transmittance and uniformity of an optical fiber image transmission element involved in the patent application with publication number CN111442908A). The test principle is to irradiate a beam of 520nm collimated incident light to the input end of the light cone, receive the light from the output end of the light cone through a CCD camera, obtain a light intensity distribution diagram, and calculate the relative transmittance by the luminous flux of the input and output light. Among them, the luminous flux is equal to the light intensity multiplied by the area, and the light intensity is measured by the transmittance tester.

The coaxiality test of the following embodiments 1-4: the center position of the light cone and the center position of the film layer are obtained in turn by a projector, both positions have X and Y coordinates, and the coaxiality C is obtained by calculation. Among them, x1, y1 are the center positions of the light cone, x2, y2 are the center positions of the film layer, and C is the coaxiality of the light cone.

The repeatability test of the following Examples 1-4: The same process was used for coating three times, and the thickness of the film at the same position was obtained three times, n1, n2, n3. The average value n = (n1 + n2 + n3) / 3, the repeatability R1 = (n1-n) / n, R2 = (n2-n) / n, R3 = (n3-n) / n, and the smallest repeatability value was taken as the repeatability of the example.

The non-uniformity test of the following examples 1-4 and comparative example 1: the non-uniformity is obtained by subtracting the relative transmittance of the smallest effective diameter range from the highest relative transmittance within the effective diameter range. Among them, the effective diameter in examples 1-4 is 20 mm, the end face of the coating is the small end of the light cone, the diameter of the small end is 53/2=26.5 mm, the effective diameter is definitely less than 26.5 mm, and examples 1-4 take 20 mm, which is 75% of the external dimensions of the small end. Specifically, the light intensity value Ci within the effective diameter of 20 _mm is selected by the above-mentioned transmittance tester to test the small end of the light cone, that is, the light intensity value of all points within the diameter of 26.5 mm. At the same time, the light intensity value of the 20 mm diameter area under the blank sample (without light cone) is tested, and the light intensity value _Ci of the light cone test is divided by the light intensity value C ₀ of the blank, that is, the relative transmittance Ti=C _i /C ₀ of any position of the small end of the light cone is obtained, and the non-uniformity value can be obtained by subtracting the minimum relative transmittance T _min from the maximum relative transmittance T _max .

Example 1

The large end A sample 9 (light cone) with a cone ratio of 2:1 and a height of 46 mm is placed in the sample chamber 7 , and the mask plate 6 is fixed below the outside of the rotating base 5 .

A high-stability, high-coaxiality mechanical rotating light cone coating device is placed in the chamber of the magnetron sputtering coating machine, and the motor 2 is controlled to rotate at a speed of 10 rpm.

After closing the chamber, first turn on the mechanical pump to pre-evacuate. When the vacuum reaches 10Pa, turn off the mechanical pump, open the solenoid valve, and turn on the molecular pump. A single mechanical pump cannot achieve a high vacuum, but it can be combined with a molecular pump to control the vacuum to 2×10 ^{- 4} Pa.

When the vacuum degree reaches 2×10 ^-4 Pa, the gas flow meter is turned on to adjust the gas flow rates of argon and oxygen to 20 sccm (ml per minute), and then the pressure in the chamber is adjusted to 0.8 Pa through the G valve.

Turn on the sputtering power switch, adjust the power to 50W to start pre-sputtering (the sputtering material is a titanium nitride target with a purity of 99.99%), open the baffle valve after sputtering for 5 minutes, adjust the power to 80W to start formal sputtering, and the sputtering time is 5 minutes.

After sputtering is completed, close the baffle valve, turn off the power switch, turn the gas flow meter knob to 0, close the solenoid valve, turn off the molecular pump, and open the valve connected to the air to balance the atmospheric pressure inside and outside the chamber.

The chamber is opened, and the high-stability, high-coaxiality mechanical rotating light cone coating device is taken out, and the coating is completed.

A TiN film with a center thickness of 70nm and an edge thickness of 50nm was plated. The non-uniformity of the light cone in the effective area after coating was 2.5%, and the center transmittance was 32%. The "center" refers to the exact center position of the light cone, and the "edge" refers to the edge position of the effective area of the light cone. The diameter of the small end face of the light cone after coating is 26.5mm, and the effective area is 20mm (its size is determined according to user requirements). The test results are shown in Figure 10. As shown in Figure 10, in the effective area, when there is no coating, the highest transmittance (i.e., center transmittance) of the light cone is 47%, the minimum transmittance is 32%, and the non-uniformity is 15%. This is caused by the difference in the image transmission path between the edge of the light cone itself and the center optical fiber. Through the high-stability, high-coaxiality mechanical rotating light cone coating device of the present invention, a step-by-step film layer can be formed on the surface of the light cone, the center transmittance is reduced to a certain extent, and the change of the film layer from the center to the edge is continuously thinned. The above coating method can homogenize the transmittance of the light cone, so that the transmittance fluctuation of the entire light cone surface is relatively small. Through Example 1, the non-uniformity of 15% can be reduced to 2.5%.

Example 2

The large end A sample 9 (light cone) with a cone ratio of 2:1 and a height of 46 mm is placed in the sample chamber 7 , and the mask plate 6 is fixed below the outside of the rotating base 5 .

A high-stability, high-coaxiality mechanical rotating light cone coating device is placed in the chamber of the magnetron sputtering coating machine, and the motor 2 is controlled to rotate at a speed of 10 rpm.

After closing the chamber, first turn on the mechanical pump to pre-evacuate. When the vacuum reaches 10Pa, turn off the mechanical pump, open the solenoid valve, and turn on the molecular pump. A single mechanical pump cannot achieve a high vacuum, but it can be combined with a molecular pump to control the vacuum to 2×10 ^{- 4} Pa.

When the vacuum degree reaches 2×10 ^-4 Pa, the gas flow meter is turned on to adjust the gas flow rates of argon and oxygen to 20 sccm (ml per minute), and then the pressure in the chamber is adjusted to 0.8 Pa through the G valve.

Turn on the sputtering power switch, adjust the power to 50W to start pre-sputtering (the sputtering material is a chromium target with a purity of 99.99%), open the baffle valve after sputtering for 5 minutes, adjust the power to 80W to start formal sputtering, and the sputtering time is 3 minutes.

After sputtering, close the flapper valve, turn off the power switch, turn the gas flow meter knob to 0, close the solenoid valve, turn off the molecular pump, and open the valve connected to the air to balance the atmospheric pressure inside and outside the chamber. A single mechanical pump cannot achieve a high vacuum degree, but it can be combined with a molecular pump to control the vacuum degree to 2×10 ^-4 Pa.

The chamber is opened, and the high-stability, high-coaxiality mechanical rotating light cone coating device is taken out, and the coating is completed.

The chamber was closed, the vacuum degree was reduced to 1×10 ^-4 Pa, and a Cr film with a center thickness of 9 nm and an edge thickness of 1 nm was deposited.

A Cr film with a center thickness of 9nm and an edge thickness of 1nm was plated. The non-uniformity of the light cone in the effective area after coating was 2.4%, and the center transmittance was 23%. The "center" refers to the exact center of the light cone, and the "edge" refers to the edge of the effective area of the light cone. The diameter of the small end face of the light cone after coating is 26.5mm, and the effective area is 20mm (its size is determined according to user requirements). The test results are shown in Figure 11. As shown in Figure 11, in the effective area, when there is no coating, the highest transmittance (i.e., center transmittance) of the light cone is 47%, the minimum transmittance is 32%, and the non-uniformity is 15%. This is caused by the difference in the image transmission path between the edge of the light cone itself and the center optical fiber. Through the high-stability, high-coaxiality mechanical rotating light cone coating device of the present invention, a step-by-step gradient film layer can be formed on the surface of the light cone, the center transmittance is reduced to a certain extent, and the film layer changes continuously from the center to the edge. The above coating method can homogenize the transmittance of the light cone, so that the transmittance fluctuation of the entire light cone surface is relatively small. Through Example 2, the non-uniformity of 15% can be reduced to 2.4%.

Example 3

The large end A sample 9 (light cone) with a cone ratio of 2:1 and a height of 46 mm is placed in the sample chamber 7 , and the mask plate 6 is fixed below the outside of the rotating base 5 .

A high-stability, high-coaxiality mechanical rotating light cone coating device is placed in the chamber of the magnetron sputtering coating machine, and the motor 2 is controlled to rotate at a speed of 10 rpm.

After closing the chamber, first turn on the mechanical pump to pre-evacuate the chamber. When the vacuum reaches 10 Pa, turn off the mechanical pump, open the solenoid valve, and then turn on the molecular pump.

When the vacuum degree reaches 2×10 ^-4 Pa, the gas flow meter is turned on to adjust the gas flow rates of argon and oxygen to 20 sccm (ml per minute), and then the pressure in the chamber is adjusted to 0.8 Pa through the G valve.

Turn on the sputtering power switch, adjust the power to 50W to start pre-sputtering (the sputtering material is a chromium target with a purity of 99.99%), open the baffle valve after sputtering for 5 minutes, adjust the power to 80W to start formal sputtering, and the sputtering time is 2 minutes.

After sputtering, close the flapper valve, turn off the power switch, turn the gas flow meter knob to 0, close the solenoid valve, turn off the molecular pump, and open the valve connected to the air to balance the atmospheric pressure inside and outside the chamber. A single mechanical pump cannot achieve a high vacuum degree, but it can be combined with a molecular pump to control the vacuum degree to 2×10 ^-4 Pa.

The chamber is opened, and the high-stability, high-coaxiality mechanical rotating light cone coating device is taken out, and the coating is completed.

A Cr film with a center thickness of 5nm and an edge thickness of 1nm was plated. The non-uniformity of the light cone in the effective area after coating was 1.9%, and the center transmittance was 28%. The "center" refers to the exact center of the light cone, and the "edge" refers to the edge of the effective area of the light cone. The diameter of the small end face of the light cone after coating is 26.5mm, and the effective area is 20mm (its size is determined according to user requirements). The test results are shown in Figure 12. As shown in Figure 12, in the effective area, when there is no coating, the highest transmittance of the light cone is 47%, the minimum transmittance is 32%, and the non-uniformity is 15%. This is caused by the difference in the image transmission path between the edge of the light cone itself and the center optical fiber. Through the high-stability, high-coaxiality mechanical rotating light cone coating device of the present invention, a step-by-step gradient film layer can be formed on the surface of the light cone, the center transmittance is reduced to a certain extent, and the film layer changes continuously from the center to the edge. The above coating method can homogenize the transmittance of the light cone, so that the transmittance fluctuation of the entire light cone surface is relatively small. Through Example 3, the non-uniformity of 15% can be reduced to 1.9%.

Example 4

The large end A sample 9 (light cone) with a cone ratio of 2:1 and a height of 46 cm is placed in the sample chamber 7 , and the mask plate 6 is fixed below the outside of the rotating base 5 .

A high-stability, high-coaxiality mechanical rotating light cone coating device is placed in the chamber of the magnetron sputtering coating machine, and the motor 2 is controlled to rotate at a speed of 10 rpm.

After closing the chamber, first turn on the mechanical pump to pre-evacuate the chamber. When the vacuum reaches 10 Pa, turn off the mechanical pump, open the solenoid valve, and then turn on the molecular pump.

When the vacuum degree reaches 2×10 ^-4 Pa, the gas flow meter is turned on to adjust the gas flow rates of argon and oxygen to 20 sccm (ml per minute), and then the pressure in the chamber is adjusted to 0.8 Pa through the G valve.

Turn on the sputtering power switch, adjust the power to 50 W to start pre-sputtering (the sputtering material is a chromium target with a purity of 99.99%), open the baffle valve after sputtering for 5 minutes, adjust the power to 80 W to start formal sputtering, and the sputtering time is 3 minutes.

After sputtering, close the flapper valve, turn off the power switch, turn the gas flow meter knob to 0, close the solenoid valve, turn off the molecular pump, and open the valve connected to the air to balance the atmospheric pressure inside and outside the chamber. A single mechanical pump cannot achieve a high vacuum degree, but it can be combined with a molecular pump to control the vacuum degree to 2×10 ^-4 Pa.

The chamber is opened, and the high-stability, high-coaxiality mechanical rotating light cone coating device is taken out, and the coating is completed.

A Cr film with a center thickness of 9nm and an edge thickness of 1nm is plated. After the Cr film is successfully plated, a 20nm thick _MgF2 film is plated (the thickness is uniform, all 20nm) to increase the transmittance of the light cone.

The non-uniformity of the light cone in the effective area after coating with Cr film is 2.4%, and the central transmittance is 41%. Wherein "center" refers to the exact center position of the light cone, and "edge" refers to the edge position of the effective area of the light cone. The diameter of the small end face of the light cone after coating is 26.5mm, and the effective area is 20mm (its size is determined according to user requirements), and the test results are shown in Figure 13. As shown in Figure 13, in the effective area, when there is no coating, the highest transmittance of the light cone is 47%, the minimum transmittance is 32%, and the non-uniformity is 15%. This is caused by the different optical fiber image transmission paths of the edge of the light cone itself and the center. Through the high-stability, high-coaxiality mechanical rotating light cone coating device of the present invention, a step-by-step film layer can be formed on the surface of the light cone, and the transmittance of the center is reduced to a certain extent. From the center to the edge, the change of the film layer is continuously thinned. In order to improve the overall transmittance of the light cone, the above-mentioned coating method coats a layer of MgF2 material with a thickness of 20nm at the other end of the light cone. This setting not only achieves the effect of homogenizing the transmitted light, but also improves the transmittance. Compared with Example 2, the central transmittance is increased by 18%.

The performance data of Examples 1-4 are summarized in Table 1 below.

Table 1

Comparative Example 1:

The large end The light cone with a cone ratio of 2:1 and a height of 46 mm is placed on a fixture in the chamber of the magnetron sputtering coater.

After closing the chamber, first turn on the mechanical pump to pre-evacuate the chamber. When the vacuum reaches 10 Pa, turn off the mechanical pump, open the solenoid valve, and then turn on the molecular pump.

When the vacuum degree reaches 2×10 ^-4 , the gas flow meter is turned on to adjust the gas flow rate of argon to 20 sccm, and then the pressure in the chamber is adjusted to 0.8 Pa through the G valve.

Turn on the sputtering power switch, adjust the power to 50W to start pre-sputtering, open the baffle valve after sputtering for 5 minutes, adjust the power to 80W to start formal sputtering, and the sputtering time is 3 minutes.

After sputtering is completed, close the baffle valve, turn off the power switch, turn the gas flow meter knob to 0, close the solenoid valve, turn off the molecular pump, and open the valve connected to the air to balance the atmospheric pressure inside and outside the chamber.

Open the chamber, take out the light cone, and the coating is completed.

A Cr film with an overall thickness of 9 nm was plated. After the coating, the non-uniformity of the light cone in the effective area became 10%, and the central transmittance dropped to 32%. The test results are shown in FIG9 .

The performance data of Comparative Example 1 are summarized in Table 2 below.

Table 2

From the data of Examples 1-4, Comparative Example 1, Table 1 and Table 2, it can be seen that, compared with Comparative Example 1, when the film layer is titanium nitride and the light cone size is 53 mm, the non-uniformity and central transmittance of the obtained light cone in the effective area are 2.4% and 32% respectively. When the film layer is replaced with chromium and the other parameters remain unchanged, the non-uniformity of the obtained light cone in the effective area is slightly reduced and the central transmittance is significantly reduced, mainly because chromium has a higher absorption coefficient than titanium nitride; then the process parameters of the coating are adjusted to reduce the thickness of the central area of the edge chromium film, and the non-uniformity of the obtained light cone in the effective area is reduced, while the transmittance is increased, the main reason for which is the thinning of the film layer; compared with Example 2, Example 4 is additionally coated with a layer of _MgF2 film, the non-uniformity does not change, and the transmittance is significantly increased to 41%, mainly because the _MgF2 film significantly reduces the reflection of light on the surface, thereby increasing the transmittance, the increase is 78%.

The present invention realizes the effect of gradient film layer by using a rotating device in combination with a snail-shaped mask plate, while the conventional coating method in the prior art obtains a film layer with uniform thickness, which cannot improve the vignetting transmittance of the light cone. The above-mentioned "vignetting transmittance" refers to the transmittance that is high in the middle and low at the edge.

In the specification of the present invention, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some embodiments, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this specification.

It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention still falls within the scope of the technical solution of the present invention.

Claims (12)

1. The mechanical rotary light cone film plating device with high stability and high coaxiality is characterized by comprising a rotary base, a mask plate and a sample bin;

the lower end face of the sample bin is fixed with the inside of the rotating base through screws, the size of the lower end face of the sample bin is smaller than that of the inside of the rotating base, and the upper end face of the sample bin is fixed with the platform through screws; the outer lower end face of the rotating base is fixed with the mask plate and drives the mask plate to rotate.

2. The high stability, high coaxiality mechanical rotary light cone coating device of claim 1 wherein the sample is placed inside the sample bin.

3. The high-stability high-coaxiality mechanical rotary light cone coating device according to claim 1, wherein a rubber pad is arranged between the inside of the sample bin and the gap of the sample.

4. The high-stability high-coaxiality mechanical rotary light cone coating device according to claim 1, wherein one end of the platform is fixed with the motor through a screw.

5. The high stability, high coaxiality mechanical rotary light cone coating device of claim 1 further comprising a motor shaft, said motor shaft being longitudinally positioned and a pinion mounted on the tail of said motor shaft.

6. The high-stability high-coaxiality mechanical rotary light cone coating device according to claim 5, wherein the pinion is connected with the large gear to form a transmission device, and the pinion drives the large gear to rotate; the rotation speed ratio of the small gear to the large gear is (4-6): 1.

7. the high-stability high-coaxiality mechanical rotary light cone coating device according to claim 6, wherein the large gear is fixed with the outer upper end of the rotary base through screws, the large gear and the rotary base are identical in size, and the large gear drives the rotary base to rotate.

8. The high-stability high-coaxiality mechanical rotary light cone coating device according to claim 1, wherein the rotary base is a bearing structure consisting of two concentric rings, and comprises a non-rotary inner structure and a rotary outer structure which are connected through steel balls; the inner structure is fixed with the sample bin, the upper end face of the outer structure is fixed with the large gear, and the lower end face of the outer structure is fixed with the mask plate and drives the mask plate to rotate.

9. The high-stability high-coaxiality mechanical rotary light cone coating device of claim 8, wherein a gap of 1-2mm is reserved between the mask plate and the rotary base.

10. The light cone coating method is characterized by comprising the following steps of:

1) Placing the assembled high-stability and high-coaxiality mechanical rotary light cone coating device in a chamber of coating equipment;

2) Turning on a power supply and adjusting the rotating speed of the mechanical rotary light cone coating device with high stability and high coaxiality;

3) Closing the chamber to begin coating.

11. The method of claim 10, wherein in step 1), the coating apparatus is a vacuum evaporation coating machine, an electron beam evaporation coating machine, or a magnetron sputtering coating machine.

12. The method of claim 10, wherein in step 2), the rotation speed of the high-stability high-coaxiality mechanical rotary light cone coating device is adjusted to 10-15rpm.