A rapid prototyping method and system for functional microstructure optical elements

Abstract

The present invention belongs to the field of microstructure lens manufacturing technology and discloses a rapid prototyping method and system for functional microstructure optical elements. The prototyping method includes: planning a tool path using slow-tool servo turning technology; machining a lens mold using ultrasonic vibration-assisted cutting amplitude engraving technology and slow-tool servo turning technology, wherein the tool cuts along a spiral according to the tool path during slow-tool servo turning; machining a microlens array on the lens mold using elliptical vibration cutting technology to obtain an optical element mold; and performing microstructure molding on the optical element mold to obtain a microstructure optical element. The present invention can greatly improve the processing efficiency of microstructure optical elements and avoid tool wear during processing.

Description

Technical Field

[0001] The present invention belongs to the technical field of microstructure lens manufacturing, and more specifically, relates to a rapid prototyping method and system for functional microstructure optical elements. Background Art

[0002] Device surfaces with microstructures are also called functional surfaces or textured surfaces. Compared with smooth surfaces of the same material, surfaces with microstructures have many excellent properties in physics, biology, engineering and other fields. In recent years, microstructured surfaces have been applied to many advanced fields such as electronics, information technology, optics and biomedicine.

[0003] Existing functional microstructure surfaces are usually formed in the following ways: through bottom-up additive manufacturing, but this processing method usually only randomly produces the size, direction and distribution of the microstructure. In this spontaneous process, it is difficult to flexibly adjust the characteristic size of the created microstructure, resulting in difficulty in controlling the surface properties; through chemical etching, but chemical etching is usually limited to specific materials and has low applicability; through laser-assisted processing, although laser-assisted processing has high efficiency and can be used for difficult-to-process materials with high hardness and low plasticity, the mechanism of the laser's influence on the material near the processing area has not been fully elucidated, and the high temperature brought by the laser may cause irreversible surface and sub-surface damage; the self-forming surface shape obtained by friction and wear is limited by the hardened area, and the current related research is not rich enough to obtain functional microstructure surface devices that meet the requirements.

[0004] Among microstructure processing methods, ultra-precision cutting in mechanical processing has the advantages of high precision, high flexibility and low cost. It can achieve high-quality surface processing with submicron shape accuracy and nanometer surface roughness, and can also realize the direct preparation of nanometer-level roughness microstructures. It can also improve large-scale batch production capabilities by cooperating with molding technology. However, severe tool wear will limit the application of diamond cutting on ferrous metals. Therefore, there is an urgent need for an ultra-precision cutting method that can avoid tool wear and microstructure surface and subsurface damage to prepare functional microstructure devices that meet the requirements. Summary of the Invention

[0005] In view of the defects of the prior art, the purpose of the present invention is to provide a method and system for rapid prototyping of functional microstructure optical elements, so as to overcome the problem that the prior art is difficult to manufacture functional microstructure devices that can avoid microstructure surface damage and sub-surface damage.

[0006] To achieve the above objectives, the present invention provides a method and system for rapid prototyping of functional microstructured optical elements, the prototyping method comprising:

[0007] S1, planning the tool path for slow tool servo turning;

[0008] S2. Processing a lens mold by combining ultrasonic vibration-assisted cutting amplitude engraving technology and slow tool servo turning technology, wherein when turning using the slow tool servo turning technology, the tool is turned along a spiral line and according to the tool path;

[0009] S3. Processing a microlens array on the lens mold based on elliptical vibration cutting technology to obtain an optical element mold;

[0010] S4. Performing microstructure molding on the optical element mold to obtain the microstructure optical element.

[0011] Furthermore, in step S1, the tool path planning method includes:

[0012] S101, determining the initial polar radius ρ0 and the tool feed rate feed of the tool path, thereby obtaining a determined helical trajectory;

[0013] S102, dividing the spiral into a plurality of arcs of equal length S;

[0014] S103, using the equal arc length S, obtaining the polar radius ρ of each point on the spiral trajectory and the step angle Δθ between the previous point and the next point;

[0015] S104 , calculating the abscissa and ordinate of each point using the polar radius ρ and the step angle Δθ, thereby obtaining the tool path.

[0016] Furthermore, in step S103, the polar radius satisfies the relationship:

[0017]

[0018] Where feed is the feed amount of one turn of the helix, ρ0 is the initial polar radius, △θ=θ2-θ1, θ1 is the starting angle of the tool, θ2 is the stopping angle of the tool, and △θ is the step angle when the tool rotates from the previous point to the next point along the helix;

[0019] Preferably, in step S104, the horizontal coordinate value is: x=ρcosθ1, and the vertical coordinate value is: y=ρsinθ1.

[0020] Furthermore, when Δθ is greater than the preset angular velocity, in step S103 , Δθ is taken as a fixed value, and the fixed value is used to obtain the polar radius ρ of each point on the remaining spiral trajectory.

[0021] Furthermore, the acceleration of the tool between two adjacent points on the spiral line is not greater than a preset acceleration; preferably, the preset acceleration value is 0.5 rad / s 2 .

[0022] Furthermore, when cutting using ultrasonic vibration-assisted cutting amplitude engraving technology, cutting is performed at a preset constant linear speed;

[0023] Preferably, the constant linear velocity satisfies:

[0024]

[0025] Where V is the constant linear velocity, v is the ultrasonic vibration velocity, and:

[0026]

[0027] Wherein, T is the ultrasonic vibration period, and a is the ultrasonic vibration amplitude.

[0028] Furthermore, when turning is performed along the tool path of the spiral using the slow tool servo turning technology, when the tool feeds to the inner circle of the spiral and the feed speed reaches a preset speed, the ultrasonic vibration assisted cutting is converted into constant speed cutting according to the preset speed; preferably, when cutting is performed using the ultrasonic vibration assisted cutting amplitude engraving technology, a combination of cutting fluid and air is used to cool the cutting area to suppress the thermochemical reaction between the tool and the workpiece.

[0029] Furthermore, the microstructure molding process in step S4 includes:

[0030] S401, placing the optical element mold in a preheated insulation box for pressurization;

[0031] S402, keeping the pressurized optical element mold warm for a preset time;

[0032] S403, lowering the temperature in the heat preservation box in a stepwise manner according to a preset temperature until the temperature drops to the preset temperature to obtain the microstructure optical element.

[0033] According to another aspect of the present invention, a rapid prototyping system for a functional microstructured optical element is also disclosed. The rapid prototyping method for a functional microstructured optical element as described above can be implemented on the prototyping system. The prototyping system includes an ultra-precision manufacturing device for a microstructured surface mold and a microlens molding device, wherein:

[0034] The ultra-precision manufacturing equipment for microstructured surface molds is used to manufacture lens molds using ultrasonic vibration-assisted cutting amplitude engraving technology and slow tool servo turning technology, wherein when turning using the slow tool servo turning technology, the tool is turned along a spiral line and according to a pre-planned tool path; it is also used to manufacture a microlens array on the lens mold based on elliptical vibration cutting technology to obtain an optical element mold;

[0035] The microlens molding equipment is used to perform microstructure molding processing on the optical element mold, thereby obtaining the microstructure optical element.

[0036] Furthermore, the forming system also includes an optical path testing device, which includes a coaxially arranged laser power supply, a window, a spot detector and a computer in sequence. When working, the microstructure optical element is placed between the laser power supply and the window, and the laser power supply emits a test laser. The test laser penetrates the microstructure optical element and enters the window. The window is used to isolate the functional optical path from the test optical path. Finally, the test optical path is transmitted to the computer through the spot detector to perform light measurement on the microstructure optical element.

[0037] The above technical solution conceived by the present invention has the following advantages compared with the prior art:

[0038] 1. The present invention utilizes ultrasonic vibration-assisted cutting amplitude engraving technology and slow tool servo turning technology to process lens molds. The ultrasonic vibration-assisted cutting amplitude engraving technology (i.e., ultrasonic vibration-assisted cutting amplitude control engraving technology) can perform fine microstructure engraving or tool compensation by controlling the vibration amplitude of ultrasonic vibration in ultrasonic vibration-assisted cutting, and change the cutting depth in each cycle by changing the amplitude in the cutting depth direction in real time. Specifically, the change in the cutting depth direction amplitude can be achieved by changing the vibration trajectory, and then a microstructure is directly generated on the workpiece surface. Therefore, the use of this technology can effectively improve the microstructure manufacturing efficiency and the complexity of the microstructure surface; the present invention also combines slow tool servo turning technology for turning, which is based on single-point diamond turning technology and cuts in a spiral form. A constant linear speed cutting method is used for cutting, wherein the constant linear speed cutting method is twice as efficient as the traditional constant speed cutting method, greatly improving the slow tool servo processing efficiency and avoiding tool wear.

[0039] 2. The slow tool servo turning processing technology of the present invention performs tool movement according to a pre-planned tool path. When planning the tool path, the initial polar radius and feed rate are first determined, so that the spiral line can be determined by the initial polar radius and feed rate; since the tool feeds from the edge, the starting position of the tool is at the outermost edge, and the polar radius at this time is exactly the initial polar radius. The initial rotation angle of the tool is set to 0°, and then the spiral line is divided into multiple equal arc lengths. According to the determined spiral line and the initial rotation angle of the tool and the set equal arc lengths, the polar radius and rotation angle of the next point can be easily found, and so on, until the polar radius and rotation angle of all remaining points are found, thereby calculating the coordinates of all trajectory points on the spiral line; this path planning method is simple to calculate and the planning time is short.

[0040] 3. The tool path planned in the present invention is consistent with the actual processing, that is, the point spacing and time interval set in this path planning method just correspond to the linear speed required during processing.

[0041] 4. In the present invention, specific values for the constant linear velocity are specified according to different microstructure manufacturing requirements. In order to make the ultrasonic vibration have a better separation effect, the constant linear velocity must be set to be less than one twentieth of the ultrasonic vibration velocity, which can make the mold processing effect better and enable the processed microstructure surface to have better surface quality, higher surface accuracy and lower sub-surface damage.

[0042] 5. After the lens mold is processed in the present invention, a microlens array is processed on the lens mold based on the elliptical vibration cutting technology. The single crystal diamond tool used to process the microlens array on the mold steel has less wear, and the edge arc of the tool remains basically intact after processing, so the surface quality of the processed microlens array is higher.

[0043] 6. Ultrasonic vibration precision machining offers unparalleled advantages in microlenses, but its separation efficiency requires very slow processing speeds, significantly restricting the efficient mass production of microlenses. The forming system designed in this invention, comprising ultra-precision microstructure surface mold manufacturing equipment and microlens molding equipment, can not only produce optical molds with ultra-high surface quality and extremely low subsurface damage, but also utilize these molds for high-efficiency, high-volume molding of high-quality microlenses. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A schematic flow chart of a rapid prototyping method for a functional microstructure optical element provided by the present invention;

[0045] Figure 2 A flowchart of manufacturing a microstructured lens according to Example 1 of the present invention;

[0046] Figure 3A schematic structural diagram of an ultra-precision manufacturing device for a microstructured surface mold according to embodiment 2 of the present invention;

[0047] Figure 4 A schematic structural diagram of a microlens molding device provided in Example 2 of the present invention;

[0048] Figure 5 This is a schematic diagram of the test optical path process provided in Example 2 of the present invention;

[0049] Figure 6 A schematic diagram of a spiral trajectory provided in Example 1 of the present invention;

[0050] Figure 7 A schematic diagram illustrating the principle of the ultrasonic vibration-assisted cutting amplitude engraving technology provided by an embodiment of the present invention;

[0051] Figure 8 This is a schematic diagram of the slow tool servo path planning principle provided in Example 1 of the present invention.

[0052] In the figure: A-microstructure surface mold ultra-precision manufacturing equipment, A001-ultra-precision machine tool, A002-signal generator, A003-power amplifier, A004-ultrasonic vibration assisted cutting device, A005-lens mold to be processed, B-microlens molding equipment, B001-temperature controller, B002-end cover, B003-molding substrate, B004-lens mold, B005-base plate, B006-heating box, C001-laser power supply, C002-microstructure lens, C003-window, C004 spot detector, C005-laser power supply, C006-computer, D-cutting direction, E-vibration trajectory, F-vibration trajectory center, G-target microstructure contour. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0054] Combine Figure 1-2 As shown, the present invention provides a method for rapid prototyping of a functional microstructure optical element, comprising the following steps:

[0055] S1. Plan the tool path of the slow tool servo turning technology and set it as the tool path of the tool in the microstructure surface mold ultra-precision manufacturing equipment A;

[0056] S2, using ultrasonic vibration assisted cutting amplitude engraving technology and slow tool servo turning technology, the lens mold is processed on the processing machine tool of the micro-structure surface mold ultra-precision manufacturing equipment A, wherein, when turning using the slow tool servo turning technology, the tool moves along Figure 6 The tool moves in a spiral path as shown, and turns according to the pre-planned tool path;

[0057] S3. Based on the elliptical vibration cutting technology, a microlens array is processed on the lens mold to obtain an optical element mold;

[0058] S4. Performing microstructure molding on the optical element mold to obtain a microstructure optical element.

[0059] In a preferred embodiment, in step S1, the tool path planning method includes:

[0060] S101, determining the initial polar radius ρ0 and the tool feed rate feed of the tool path, thereby obtaining a determined helical trajectory;

[0061] S102, setting the initial rotation angle of the spiral to 0°, and dividing the spiral into a number of arcs of equal length S;

[0062] S103, using the equal arc length S, obtain the polar radius ρ and the rotation step angle △θ of each point on the spiral trajectory;

[0063] S104 , calculating the horizontal coordinate and vertical coordinate of each point using the polar radius and the rotation step angle Δθ, thereby obtaining a tool path.

[0064] In a preferred embodiment, in the aforementioned step S103, the polar radius satisfies the following relationship:

[0065]

[0066] Where feed is the feed amount of one circle in the helix, ρ0 is the initial polar radius, △θ=θ2-θ1, θ1 is the starting angle of the current point, θ2 is the stopping angle of the current point, and △θ is the step angle of the tool along the helix.

[0067] In a more preferred embodiment, in step S104 , the abscissa value is: x=ρcosθ1, and the ordinate value is: y=ρsinθ1.

[0068] In a preferred embodiment, when the aforementioned Δθ is greater than the preset angular velocity, in step S103, Δθ is taken as a fixed value, and the fixed value is used to obtain the polar radius ρ of each point on the remaining spiral trajectory, and the calculation formula is the same as formula (1).

[0069] In a preferred embodiment, the acceleration of the tool between two adjacent points on the spiral line is not greater than a preset acceleration; preferably, the preset acceleration value is 0.5 rad / s 2 .

[0070] In a preferred embodiment, when cutting using ultrasonic vibration-assisted cutting amplitude engraving technology, cutting is performed at a preset constant linear speed; preferably, the constant linear speed satisfies:

[0071]

[0072] Where V is the constant linear velocity, v is the ultrasonic vibration velocity, and:

[0073]

[0074] Wherein, T is the ultrasonic vibration period, T=1 / f, f is the ultrasonic vibration frequency, and a is the ultrasonic vibration amplitude.

[0075] In a preferred embodiment, when turning along the tool path of the spiral using slow tool servo turning technology, when the tool feeds to the inner circle of the spiral and the feed speed reaches a preset speed, the ultrasonic vibration assisted cutting is converted to constant speed cutting according to the preset speed. The reason is: since the ultrasonic vibration assisted cutting amplitude engraving technology has higher efficiency and accuracy at a constant linear speed, a constant linear speed is set during the feeding process. However, the problem caused by the constant linear speed is that the angular velocity in the inner circle will be very large, which is more difficult for the machine tool to process. Therefore, the maximum angular velocity needs to be set. When the tool feeds to the inner circle and reaches a set angular velocity, the constant linear speed processing mode is converted to a constant angular velocity (i.e., constant speed cutting).

[0076] In a preferred embodiment, when cutting is performed using ultrasonic vibration-assisted cutting amplitude engraving technology, a cutting fluid and air are combined to cool the cutting area to suppress the thermochemical reaction between the tool and the workpiece. The cutting fluid includes oil-based cutting fluid, semi-synthetic cutting fluid and fully synthetic cutting fluid.

[0077] In a preferred embodiment, during the microstructure molding process, the optical element mold is first placed in a preheated insulation box for pressurization, and then the pressurized optical element mold is kept warm for a preset time, and then the temperature in the insulation box is lowered in steps according to the preset temperature until it drops to the preset temperature to obtain a microstructure optical element. After the microstructure molding process is completed, the microstructure optical element is also subjected to an optical path test. After passing the test, a microstructure optical element that meets the requirements is obtained.

[0078] Example 1

[0079] The flow chart of a rapid prototyping method of a functional microstructure optical element provided in this embodiment is as follows: Figure 1 As shown, the specific steps of the forming method include:

[0080] S1. Plan the tool path for the slow tool servo turning technology and set it as the tool path for the tool in the microstructure surface mold ultra-precision manufacturing equipment A:

[0081] During the slow tool servo turning process, the tool motion trajectory feeds from the outside to the inside along the spiral line. When planning the tool path, Figure 8 As shown, first use Matlab to calculate the spiral line under different linear speeds and feed rates, and then take points on the spiral line to obtain Figure 8 The x and y coordinates of the trajectory points in different microstructures shown in a are obtained at the same time, and the microlens point cloud is obtained. The microlens point cloud includes the three-dimensional coordinates of all trajectory points; the x and y coordinate information on the spiral line is matched with the horizontal and vertical coordinate information in the microlens point cloud, and the coordinate information in the z-axis direction is obtained. The three-dimensional coordinate information of the tool trajectory when processing the microlens according to the spiral line can be obtained; specifically, by designing different functional surface morphologies, the coordinate value of any point on the corresponding microstructure plane can be obtained, and finally the obtained x and y coordinate points are printed on Figure 8 The point cloud data during processing can be obtained from the z coordinate of the microstructure surface topography shown in b. Figure 8 Figure c in the middle is an enlarged view of the microstructure surface morphology. The point cloud data used for processing is input into the ultra-precision machining center in the ultra-precision manufacturing equipment of the microstructure surface mold, which can be used to realize the manufacturing process of the functional surface microstructure by slow tool servo turning.

[0082] Specifically, the aforementioned tool path planning method includes:

[0083] S101, the tool path is cut along a spiral line, so by determining the initial polar radius ρ0 of the tool path and the tool feed rate feed, a certain spiral line trajectory can be obtained;

[0084] S102, such as Figure 2 As shown in the figure, since the tool feeds from the edge of the spiral, the starting position is at the outermost edge. The polar radius here is exactly the initial polar radius ρ0. The initial turning angle of the spiral here is set to 0°, and the spiral is divided into multiple arcs of equal length S.

[0085] S103, using the equal arc length S to obtain the polar radius ρ and the rotation step angle △θ of each point on the spiral trajectory;

[0086] Specifically, such as Figure 2 As shown, since the initial polar radius, that is, the mold radius, is set to ρ0, the feed amount of one spiral circle is feed, and the arc feed amount corresponding to the corner angle is the feed amount of one circle 360° divided into The actual feed amount of the tool from the previous point to the next point is Then the polar radius ρ corresponding to each point satisfies the following relationship:

[0087]

[0088] Where feed is the feed amount of one circle in the helix, ρ0 is the initial polar radius, △θ=θ2-θ1, θ1 is the starting angle of the current point, θ2 is the stopping angle of the current point, and △θ is the step angle when the tool rotates from the previous point to the next point along the helix;

[0089] After obtaining the expression for ρ, we can integrate it within the intervals of θ1 and θ2 to obtain the arc length S. The arc length S should be the integral of the polar radius and the step angle, which can be expressed as:

[0090]

[0091] Since the above equation (5) is a non-homogeneous equation, it is necessary to use the Newton iteration method to infinitely approximate the solution value. This is a conventional idea and will not be explained as the focus of the present invention. After formula (5) is obtained, Δθ can be solved based on the known quantity S and the initial polar radius.

[0092] S104, calculating the horizontal coordinate and vertical coordinate of each point using the polar radius ρ and the rotation step angle Δθ, thereby obtaining a tool path;

[0093] Specifically, the horizontal coordinate value is: x=ρcosθ1, and the vertical coordinate value is: y=ρsinθ1.

[0094] When the aforementioned Δθ is greater than the preset angular velocity, in step S103, Δθ is set to a fixed value, and Δθ is used to obtain the polar radius ρ of each point remaining on the spiral trajectory. The calculation formula of the polar radius is the same as formula (4):

[0095]

[0096] This embodiment limits the specific constant linear velocity selection value according to different microstructure manufacturing requirements. Assuming that the ultrasonic vibration frequency in the ultrasonic vibration-assisted cutting amplitude engraving technology is f (Hz), its vibration period is The vibration amplitude is a (here refers to the full amplitude), then the vibration speed is:

[0097]

[0098] The arc length S is a known quantity. If the tool movement time between two adjacent points on the spiral line is set to t, the linear velocity V satisfies the following relationship:

[0099]

[0100] Then the angular velocity ω at the angle △θ is:

[0101]

[0102] Then the acceleration g from the moment t1 of the previous trajectory point to the moment t2 of the next trajectory point is:

[0103]

[0104] The above physical quantities are restricted as follows:

[0105]

[0106] Formula (11) is to make the ultrasonic vibration have a better separation effect, so the linear velocity V must be less than one twentieth of the vibration velocity v, and the processed lens mold has lower surface roughness and less pressure surface damage;

[0107] g≤g max (12)

[0108] The maximum acceleration specified here is g max 0.5rad / s 2 ;

[0109] Since ultrasonic vibration-assisted cutting amplitude engraving technology has high efficiency and precision at a constant linear speed, a constant linear speed is set during the feeding process. However, the problem with the constant linear speed is that it will cause a large angular velocity in the inner circle, which is a test for the machine tool. Therefore, a maximum angular velocity needs to be set. When the tool feeds to the inner circle and reaches a set angular velocity, the constant linear speed processing mode is converted to constant angular speed processing.

[0110] S2. Using ultrasonic vibration-assisted cutting amplitude engraving technology and slow tool servo turning technology, a polystyrene lens mold is machined on an ultra-precision machine tool of microstructure surface mold ultra-precision manufacturing equipment A. When turning using the slow tool servo turning technology, the tool is turned along a spiral line according to the tool path planned in step S1.

[0111] S3. Based on elliptical vibration cutting technology, a microlens array is processed on the lens mold to obtain an optical element mold made of polystyrene. The single crystal diamond tool used to process the microlens array on the mold steel has less wear, the tool arc remains basically intact, and the surface quality of the processed lens mold is high.

[0112] S4, performing microstructure molding on the optical element mold to obtain a microstructure optical element;

[0113] S401, placing the optical element mold in a preheated heat preservation box for pressurization:

[0114] After the optical element mold is manufactured, it is placed in a microlens molding machine for microstructure molding. During molding, since the thermal deformation temperature of polystyrene is about 90°C, the heat box where the optical element mold is placed is first heated to 105°C, and then the optical element mold is pressurized.

[0115] S402, keeping the pressurized optical element mold warm for a preset time: keeping warm for 30 minutes after pressurization;

[0116] S403, lowering the temperature in the heat preservation box in a stepwise manner according to a preset temperature until the temperature drops to the preset temperature to obtain the microstructured optical element:

[0117] The temperature is lowered at intervals of 5°C each time until the temperature stabilizes. This process is repeated until the temperature drops below 70°C. The incubator is opened for natural ventilation and cooling, thereby obtaining the desired microstructure optical element.

[0118] The molding substrate and the base plate in the microlens molding equipment used in this embodiment are made of aluminum alloy. Compared with steel, aluminum has good thermal conductivity and can fully transfer heat to the workpiece.

[0119] Example 2

[0120] Combine Figure 3-5 As shown, a rapid prototyping system for a functional microstructure optical element provided by this embodiment is described. A rapid prototyping method for a functional microstructure optical element as described in any of the above embodiments can be implemented on the prototyping system. The prototyping system includes: Figure 3 The microstructure surface mold ultra-precision manufacturing equipment A shown in FIG. Figure 4 The microlens molding device B shown, wherein:

[0121] Ultra-precision manufacturing equipment A for microstructured surface molds is used to process lens molds using ultrasonic vibration-assisted cutting amplitude engraving technology and slow tool servo turning technology. The working principle of ultrasonic vibration-assisted cutting amplitude engraving technology is as follows: Figure 7 As shown in FIG, during the ultrasonic vibration process, by changing the amplitude of the ultrasonic vibration, the ultrasonic vibration trajectory is changed according to a certain rule, thereby carving different morphological surfaces on the workpiece surface; specifically, as Figure 7 As shown in the figure, F is the center of the vibration trajectory, and G is the target microstructure contour. During processing, the tool center is kept unchanged along the cutting direction D in the figure. When the cutting direction remains unchanged, the vibration trajectory E of the tool is continuously changed, so that a surface structure of any shape can be imprinted on the surface of the workpiece. The ultrasonic vibration-assisted cutting amplitude engraving technology used in the present invention not only helps to form various surfaces, but also can complete the tool compensation during the cutting process.

[0122] The reason for tool compensation during the cutting process is that the interference of the tool's own geometric shape on the surface forming is not taken into account during tool trajectory planning. Tool compensation is to make up for the interference of the tool's own shape and fine-tune the trajectory to avoid changes in the shape. Ultrasonic vibration-assisted cutting amplitude engraving technology can change the ultrasonic vibration tool tip trajectory by changing the amplitude of the ultrasonic vibration.

[0123] Among them, when using slow tool servo turning technology, the tool turns the lens mold along the spiral line and according to the pre-planned tool path;

[0124] The microstructure surface mold ultra-precision manufacturing equipment A is also used to process a microlens array on a lens mold based on elliptical vibration cutting technology to obtain an optical element mold.

[0125] like Figure 3 As shown, the ultra-precision manufacturing equipment A for microstructure surface molds includes: an ultra-precision machine tool A001, a signal generator A002, a power amplifier A003, an ultrasonic vibration assisted cutting device A004 and a lens mold to be processed A005;

[0126] When manufacturing microstructures, the ultra-precision machine tool A001 is the machine tool used in the entire processing process, specifically an ultra-precision cutting lathe; the signal generator A002 provides the necessary voltage signal for the ultrasonic vibration-assisted cutting device A004. This voltage signal can change the voltage frequency, amplitude, phase and other parameter information according to the specific microstructure to be processed, thereby driving the vibration of different vibration trajectories at the tip of the ultrasonic vibration-assisted cutting device A004; after the signal generator A002 outputs the signal, the signal is amplified and gained by the power amplifier A003, and its gain effect is stable, so that it has sufficient voltage to drive the piezoelectric ceramic vibration inside the A004 ultrasonic vibration-assisted cutting device; finally, based on the relative movement of the ultra-precision machine tool A001 and the ultrasonic vibration-assisted cutting device A004 relative to the lens mold A005 to be processed, ultra-high precision manufacturing of the surface microstructure of the lens mold A005 to be processed is realized, and the lens mold B004 is obtained.

[0127] like Figure 4 As shown, the microlens molding device B is used to perform microstructure molding on an optical element mold to obtain a microstructure optical element. The microlens molding device B includes: a temperature controller B001, an end cap B002, a molding substrate B003, a base plate B005, and a heating box B006. The lens mold is B004 in the figure and is placed between the molding substrate B003 and the base plate B005.

[0128] The lens mold manufactured in the microstructure surface mold ultra-precision manufacturing equipment A is placed between the molding substrate B003 and the base plate B005 for microstructure lens molding. Specifically, the temperature controller B001 can accurately control the heating temperature of the heating box B006, and its temperature control accuracy is within 1°C. In addition to the heating box, during the molding process, the temperature inside the microlens molding equipment B must also be kept stable. The specific orientation of the lens molding is that the molding substrate B003 is arranged above the heating box B006, and the base plate B005 is provided with a clamping structure, which can fix the lens mold B004. The molding substrate B003 is directly above the lens mold B004, and the end cover B002 is directly above the molding substrate B003. Pressure is applied to the end cover B002 to ensure that the pressure applied to the lens mold is controllable and stable, and finally a molded microstructure optical element is obtained.

[0129] The forming system of this embodiment further includes an optical path testing device C, which includes a coaxially arranged laser power supply C001, a window C003, a spot detector C004, a laser power supply C005, and a computer C006.

[0130] When working, Figure 5 As shown, the microstructured optical element is placed between the laser power supply C001 and the window C003. The laser power supply C001 emits a test laser, which penetrates the microstructured optical element and enters the window C003. The window C003 is used to isolate the functional light path from the test light path. Finally, the test light path is transmitted to the computer C006 through the spot detector C004 for light measurement.

[0131] Among the microstructure processing methods, the present invention adopts ultra-precision cutting technology with the advantages of high precision, high flexibility and low cost. It can achieve high-quality surface processing with submicron shape accuracy and nanometer surface roughness, and can realize the direct preparation of nanometer-level roughness microstructures. It can also improve the ability of large-scale batch production by cooperating with molding technology.

[0132] In summary, the present invention has the following advantages:

[0133] 1. The tool path planning method is simple and fast, the tool path is highly compatible with actual processing, and the microlens manufacturing process is concise and specific, which can be widely promoted;

[0134] 2. The lens molds manufactured using ultrasonic vibration-assisted cutting technology have better surface quality, higher surface accuracy and lower subsurface damage;

[0135] 3. The combined technology of manufacturing lens molds of the present invention effectively improves the problem of low efficiency of ultrasonic vibration assistance, and can achieve large-scale and high-efficiency manufacturing of lenses.

[0136] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A rapid prototyping method for a functional microstructure optical element, characterized in that: The rapid prototyping method comprises: S1 plans the tool path for slow tool servo turning. The planning steps include: S101 determines the initial polar radius of the tool path and tool feed feed , thus obtaining a definite spiral line; S102: dividing the spiral into a plurality of arcs of equal length S; S103 uses the equal arc length S to obtain the polar radius of each point on the spiral line ρ and the step angle △ between the previous point and the next point θ ; S104 utilizes the polar radius ρ and the step angle △ θ Calculating the horizontal coordinate and the vertical coordinate of each point to obtain the tool path; S2 combines ultrasonic vibration-assisted cutting amplitude engraving technology and slow tool servo turning technology to process a lens mold, wherein when using the slow tool servo turning technology for turning, the tool turns along the spiral line according to the tool path; when using the ultrasonic vibration-assisted cutting amplitude engraving technology for cutting, the cutting is performed according to a preset constant linear speed, and the constant linear speed satisfies: in, V is a constant linear velocity, v is the ultrasonic vibration velocity, and: in, T is the ultrasonic vibration period, a is the ultrasonic vibration amplitude; S3 processes a microlens array on the lens mold based on elliptical vibration cutting technology to obtain an optical element mold; S4 performs microstructure molding on the optical element mold to obtain the microstructure optical element.

2. A rapid prototyping method for a functional microstructure optical element according to claim 1, characterized in that: In step S103, the polar radius satisfies the relationship: in, feed is the feed amount of one circle in the helix, is the initial polar radius, △ θ= 2- 1, 1 is the starting angle of the current point, 2 is the stop angle of the current point, △ θ It is the step angle when the tool rotates from the previous point to the next point along the helix.

3. The rapid prototyping method of a functional microstructure optical element according to claim 1, wherein: In step S104, the horizontal coordinate value is: x = 1, the vertical coordinate value is: y = 1.

4. The rapid prototyping method of a functional microstructure optical element according to claim 1, wherein: When θ When the angular velocity is greater than the preset angular velocity, in step S103, the step angle Δ θ Take it as a fixed value, and use the fixed value to calculate the polar radius of each point on the remaining spiral trajectory ρ .

5. The rapid prototyping method of a functional microstructure optical element according to claim 2, wherein: The acceleration of the tool between two adjacent points on the spiral line is no greater than a preset acceleration.

6. The rapid prototyping method of a functional microstructure optical element according to claim 5, wherein: The preset acceleration value is 0.5rad / s 2 .

7. The rapid prototyping method of a functional microstructure optical element according to claim 5, characterized in that: When turning along the tool path of a spiral using the slow tool servo turning technology, when the tool feeds to the inner circle of the spiral and the feed speed reaches a preset speed, the ultrasonic vibration-assisted cutting is converted into constant speed cutting according to the preset speed.

8. The rapid prototyping method of a functional microstructure optical element according to claim 7, wherein: When cutting using ultrasonic vibration-assisted cutting amplitude engraving technology, a combination of cutting fluid and air is used to cool the cutting area to suppress the thermochemical reaction between the tool and the workpiece.

9. The rapid prototyping method of a functional microstructure optical element according to claim 1, wherein: The microstructure molding process in step S4 includes: S401, placing the optical element mold in a preheated insulation box for pressurization; S402, keeping the pressurized optical element mold warm for a preset time; S403, lowering the temperature in the heat preservation box in a stepwise manner according to a preset temperature until the temperature drops to the preset temperature to obtain the microstructure optical element.

10. A rapid prototyping system for functional microstructure optical elements, characterized in that: The system is used to implement a rapid prototyping method for a functional microstructure optical element as described in any one of claims 1 to 9, wherein the prototyping system comprises an ultra-precision manufacturing device (A) for a microstructure surface mold and a microlens molding device (B), wherein: The ultra-precision manufacturing apparatus (A) for microstructured surface molds is used to combine ultrasonic vibration-assisted cutting amplitude engraving technology and slow tool servo turning technology to produce a lens mold, wherein, when turning using the slow tool servo turning technology, the tool of the ultra-precision manufacturing apparatus (A) for microstructured surface molds is turned along a spiral line and in accordance with a pre-planned tool path; and is also used to process a microlens array on the lens mold based on elliptical vibration cutting technology to obtain an optical element mold; The microlens molding device (B) is used to perform microstructure molding processing on the optical element mold, thereby obtaining the microstructure optical element.

11. The rapid prototyping system for a functional microstructure optical element according to claim 10, wherein: The forming system also includes an optical path testing device (C), which includes a coaxially arranged laser power supply (C001), a window (C003), a light spot detector (C004), a laser power supply (C005) and a computer (C006). When in operation, the microstructured optical element is placed between the laser power supply (C001) and the window (C003). The laser power supply (C001) emits a test laser, which penetrates the microstructured optical element and then enters the window (C003). The window (C003) is used to isolate the functional optical path from the test optical path. Finally, the test optical path is transmitted to the computer (C006) through the light spot detector (C004) to perform light measurement on the microstructured optical element.

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