KR101807712B1 - Ultra-precision fabrication method for off-axis reflective mirror surface - Google Patents

Abstract

The present invention relates to a method for ultra-precision processing a primary mirror and a secondary mirror which are an off-axis reflective optical surface through an ultra-precision processing technology. Mainly, the present invention relates to the processing method of an off-axis reflective optical surface, comprising: a fixture manufacturing step for ultra-precision processing; a main mirror manufacturing step; a secondary mirror manufacturing step; a precision measurement step; an improvement fixture manufacturing and improvement ultra-precision processing step; an aspheric ultra-precision processing step; and a gold coating step.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an ultra-

The present invention relates to a method for precisely machining main and minor diameters, which are off-axis reflective optical mirror surfaces, through ultra-precision processing technology.
Mainly (1) Manufacturing steps of super precision machining tool -> (2) Main machining step -> (3) Saddle making step -> (4) Precision measuring step -> (5) (6) an aspherical super-precision machining step- (7) a gold coating step.

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Today, we are working on the design, measurement and machining of precise mechanisms that are linked to each other based on the technical characteristics called Ultra-Precision, which is leading the development of high-tech products in modern industrial society. Presence of precise core technology toward ultra precision is positioning as a common basic technology for securing international competitiveness of various high-tech industries in one country.
[0002] Recently, super precision mirror cutting technology using diamond tools is rapidly developing. It is necessary to develop ultra precise machining process technology to understand super precise machining conditions and principle according to importance of super precise machining technology and to identify various causes of super precise machining to achieve surface precision. In Korea, researches on processing technology and machining system have been carried out in accordance with the rapid development of various precision and aerospace industries. In recent years, demand for small satellite mirror and optical parts industry of aerospace industry has increased Research and development on application technology and machining system have been actively carried out in various fields of industry, academia and research, but it is still insufficient compared to advanced countries.
In the 21st century, high-tech industries related to BT, IT, NT, and ST are newly emerging as industries that will lead the future of Korea. In addition, ultra-precision processing technology using diamond lathes is used more and more High-precision machining technology of micro-nano-units is required for a further higher processing level than the current one. Therefore, in order to meet the national technical requirements in the field of ultra-precision machining technology in Korea and to secure the technical competitiveness for advanced countries, further research on the basic technology of ultra-precision machining using diamond tools is required. Accordingly, Applicant has developed an algorithm for ultra-precise optimization of aluminum alloy (Al6061-T651) and proposes optimal processing conditions. In addition, we design the tool for precise machining and analyze the variation of the main and minor diameters to establish the optimum process technology. In order to develop optimal process technology, it is necessary to be able to measure the amount of surface change of the main and sub-bores. By verifying this experiment, we propose the technology of ultra-precision aspheric surface processing and apply it to the development of NISS I want to.
On the other hand, as a related art, Japanese Patent Application No. 10-0720275 discloses a grinding method of an asymmetric aspheric mirror. Japanese Patent Application Publication No. 10-0898924 discloses a method of processing an aspheric surface of a micro lens and a method of manufacturing an ultra- No. 10-1591569 discloses an aspherical lens polishing apparatus, and Published Utility Model No. 20-1998-0006970 describes a surface polishing abrasive for an aspheric lens.
However, the above-described techniques are considered to be different from the inventions proposed by the present applicant in terms of the control method and the object.
(Patent Literature) Patent Document 10-0720275 (Published on May 22, 2007), Patent Registration No. 10-0898924 (Published on May 26, 2009), Registered Patent Publication No. 10-1591569 ), A public utility model publication No. 20-1998-0006970 (April 30, 1998).

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According to an aspect of the present invention, there is provided a method of processing a non-shrinking optical surface according to the present invention.
A step of manufacturing a tool to fix the main and minor diameters for machining main and minor diameters; Fixing a main material to a tool made in the tool making step, and then making a main tool; Fixing the minor diameter material to the tool hole formed in the tool hole manufacturing step, and then manufacturing the minor diameter; A precise measurement step of confirming that the coupling between the 'tool and main tool' or 'tool and sub tool' produced through the tool making step, main tool making step and sub-diameter making step is included in the design tolerance; An improvement tool tip for making an improvement tool for improving the shape of the main or minor diameter through a laser interferometer and performing an improvement using the tool; An aspheric super precision machining step of machining each of the upper and lower surfaces of the main and minor diameters so as to become an aspherical surface after the improvement tool making and improvement super precision machining steps; And a gold coating step of performing gold coating on each of the primary and secondary diameters. In addition, the step of manufacturing the tool includes steps of manufacturing a main tool for forming a top tool and a bottom tool to fix the main mirror, and a sub-tool for manufacturing a sub-tool and a sub-tool for fixing the sub-tool.
The step of manufacturing the main mirror and the step of manufacturing the sub mirror may include forming an inserting portion having a concave groove protruding in a circular shape on one surface of the main surface or minor surface of the material to be a bottom surface, Precision machining step of machining the three wings so as to protrude along the outer circumference of the material, and an upper surface precision machining step of machining one surface of the material to be the upper surface.
In addition, the improvement tool is divided into a main diameter and a minor diameter, and each of the "main tool improving tool" and the "sub-tool improving tool" is formed with a concave groove from one surface, And the support structure is configured to be fastened to the main shaft or the sub shaft via fastening means.

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A step of manufacturing a tool to fix the main and minor diameters for machining main and minor diameters; Fixing a main material to a tool made in the tool making step, and then making a main tool; Fixing the minor diameter material to the tool hole formed in the tool hole manufacturing step, and then manufacturing the minor diameter; A precise measurement step of confirming that the coupling between the 'tool and the main tool' or the 'tool and the sub-tool' produced through the tool making step, main tool making step and sub-diameter making step is included in the design tolerance; An improvement tool tip for making an improvement tool for improving the shape of the main or minor diameter through a laser interferometer and performing an improvement using the tool; An aspheric super precision machining step of machining each of the upper and lower surfaces of the main and minor diameters so as to become an aspherical surface after the improvement tool making and improvement super precision machining steps; And a gold coating step of performing gold coating on each of the primary and secondary diameters,
(a) In the step of manufacturing the tool,
A step of manufacturing a main tool for manufacturing a main tool and a main tool for fixing the main mirror, and a sub-tool for manufacturing a sub tool and a sub tool for fixing the sub-
(b) fabricating the main mirror and the sub-
Wherein one of the main and minor surfaces of the material has an insert portion protruding in a circular shape on one surface to be a bottom surface and provided with a concave groove therein and a bottom surface precision machining process in which three blade portions are protruded along the protruded circular outer circumference And an upper surface precision machining step of machining a surface to be an upper surface of the one surface of the material, wherein the improvement tool is divided into a main diameter and a minor diameter, And the support structure is configured to be coupled with the main or minor diameter through the fastening means, and the support structure has a height of its height Side wall is formed concavely in the shape of "<'> in the inward direction, and a side wall contacting the support structure of the main or minor diameter is formed in the supporting structure direction Wherein the fixing cover includes a fixed cover having the same shape as the supporting structure and having a size larger than that of the supporting structure, and at the end of the fixing cover, a locking claw It is possible to improve the fastening force of the main or minor diameter and support structure,
(c)
Wherein the coating step comprises a coating step, a heating step, and a coating step, wherein the heating step heats the main or minor diameter coated with the coating agent to a temperature of 20 to 40 DEG C, And then rotating the fixed two points about the axis so that the coating agent can be uniformly coated on the surface of the main or minor diameter by the centrifugal force.

According to the method of processing a non-shrinking optical surface according to the present invention,
end. It is possible to obtain ultra-precision machining with optimum cutting conditions to obtain a surface roughness Ra of 1.4142 nm at a cutting speed of 122 m / min, a cutting depth of 3 μm and a feed rate of 5 mm / min,
I. It is possible to consider and predict various design variables through the design and manufacture of the tool bar for super precision machining of the main mirror,
All. We confirmed the position of the central part of the main and minor parts by verifying the first machining using the 3D measuring machine and verified various machining parameters in the precise machining in advance,
la. It is possible to improve the surface shape measurement through the laser interferometer to obtain excellent results,
hemp. Results of UA3P measurement after final super precision machining were 1.9224 ㎛ for main mirror and 0.5803 ㎛ for submarine PV,
bar. In the case of gold coating, there is an advantage that the reflectance performance can be ensured.

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1 shows a flow of a method of processing a non-shrinking optical surface according to the present invention.

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The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings and the inventor can properly define the concept of the term to describe its invention in the best possible way And should be construed in accordance with the principles and meanings and concepts consistent with the technical idea of the present invention.

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Therefore, the embodiments described in the present specification and drawings are only the most preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents And variations are possible.

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Before describing the present invention with reference to the accompanying drawings, it should be noted that the present invention is not described or specifically described with respect to a known configuration that can be easily added by a person skilled in the art, Let the sound be revealed.

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The present invention relates to a method for precisely machining main and minor diameters, which are off-axis reflective optical mirror surfaces, through ultra-precision processing technology.

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More specifically, it is possible to perform the ultra-precision machining of the main and minor diameters through the production of a tool for enabling the super-precision machining of the main and minor diameters, and also to reduce the amount of change through the laser interferometer, And a method of processing an optical surface.

Hereinafter, a method of processing a non-shrinking optical surface according to the present invention will be described with reference to the accompanying drawings.

1 shows a flow of a method of processing a non-shrinking optical surface according to the present invention.

The present invention with reference to Figure 1,

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(1) Precision machining tools -> (2) Main machining step -> (3) Piping machining step -> (4) Precision measurement step -> (5) 6) aspheric super-precision machining step-> (7) gold coating step.

Prior to the explanation, the super precision machining machine used in the present invention is a 450 UPL diamond turning machine (DTM) manufactured by Nanotech.

Specifically, it is as follows.

(1) Steps for manufacturing tooling

The step of fabricating the tooling tool is a step of manufacturing a tooling for fixing the main and minor diameters for super precision machining of the main and minor diameters, and it can be manufactured by dividing into the upper tool and the lower tool.

In the manufacturing step of the tool, the main tool and the sub-tool are respectively manufactured.

Such tooling is designed using an Auto CAD program and can be manufactured through a CAM based on the designed tool, which will be obvious to those skilled in the art, and thus a detailed description thereof will be omitted.

(1-1) Preparation of the main tool

The steps of manufacturing the main tool are made in accordance with the drawing in [Table 1], which is the step of manufacturing the upper tool and the lower tool to fix the main diameter.

Top tool for main spindle

Main tool

(1-2) Pumice dragon tool making stage

The manufacturing steps of Pukyong dragon tool are to manufacture the upper tool and the lower tool to fix the saddle, and it is manufactured according to the figure in [Table 2].

However, the sub-diameter tool that is manufactured at the manufacturing stage of the Pukyong tool is constructed so that only one sub-diameter can be inserted and fixed. On the other hand, the main tool used in the main tool manufacturing step is different in that two main tools are inserted and fixed.

Pukyong dragon upper tool

Pneumatic Hex Tool

(2) Main production stage

The main mirror manufacturing step is a step of fixing the main diameter material to the main diameter tool made in the step of manufacturing the tool, and then making the main diameter through super precision machining.

The production of such a main mirror is divided into a bottom surface and a top surface.

(2-1) Bottom Ultra Precision Machining Step

The bottom surface precision machining step is a step of machining one surface of the material serving as the base of the main mirror so that the one surface to be the bottom surface of the main surface has the shape shown in Table 3.

In other words, the insertion portion is formed so as to be recessed in a circular shape on the bottom surface so as to be inserted into the main tool, and the three wings are protruded along the outer periphery of the circular shape, Thereby forming a groove for use.

Thereby, the bottom surface of the main mirror can be fitted on the upper surface of the main-diameter tool shown later.

(2-2) Top surface super precision machining step

The upper surface precision machining step is a step of machining one surface of the material serving as the base of the main mirror so that the upper surface of the main mirror becomes the shape shown in Table 4.

(3) Pupil production stage

In the sub-diameter manufacturing step, the sub-diameter material is fixed to the sub-diameter tool made in the step of manufacturing the tool, and then the sub-diameter is manufactured through ultra-precision processing.

The production of these sidewalls is also divided into the bottom surface and the top surface.

(3-1) Bottom Ultra Precision Machining Step

The bottom surface precision machining step is a step of machining one surface of the minor surface of the material serving as the base of the minor surface. The shape of the bottom surface can also be the same as the bottom surface of the main surface of Table 3.

(3-2) Top surface super precision machining step

The upper surface precision machining step is a step of machining one surface of the material serving as the base of the minor diameter to be the upper surface of the minor diameter. At this time, the superfine machining step of the top surface of the sphere can also be made to be one plane like the main mirror, and both the main mirror and the sub mirror can be performed through the MCT machining.

(4) Precision measurement step

The precision measurement step is a step of precisely measuring whether the coupling between the machining tool made through the machining tool manufacturing step, the main machining manufacturing step and the sub-machining manufacturing step, the main machining tool, the tooling tool, and the sub-machining is included in the design tolerance.

That is, it is possible to use a three-dimensional measuring device as a precise measuring step in comparison with the initially designed tolerance so that each of the primary and secondary diameters can be firmly inserted into the insertion structure formed on the upper surface side of the tooling hole. .

Precision Measurement Pukyung Precision Measurement

Precision tooling Precision measurement

(5) Manufacture and improvement of tools for improvement

The main and minor diameters mentioned above have been experimented by the applicant of the present invention, and as a result, it is necessary to perform precision machining for improving the bottom surface of the main mirror and the minor mirror due to a large change in the laser interferometer measurement result.

That is, when improving the bottom surface of the primary and secondary diameters, the improvement tool tip is manufactured by manufacturing the improvement tool tip capable of fixing the main diameter and the minor diameter, and the bottom surface of the main and sub- .

Specifically, the improvement tool has a concave groove formed in one surface thereof and a convex-shaped support structure in the interior thereof, both of which are formed in the shape of [Table 6] (left-main, right-minor).

More specifically, an example in which a 'main fixation tool' is coupled to the main surface through FIGS. 2 to 4 of the accompanying drawings and FIGS. 5 to 7 illustrate an example in which a 'sub- Can be referred to.

Refer to [Table 7] for improvement processing.

On the other hand, in the case where the precision machining for improving the bottom surface of the main and minor diameters is not performed by using the tool for improvement as described above,

The main and minor diameters were assembled to the tool, and the bast radius was measured with the MCT equipment. The bottom surface was measured twice with the laser interferometer. The main shape was impossible to measure the shape and the diameter was too large with PV 14.82 ~ 19.28 μm .

However, after the improvement of the bottom surface of the main and the minor diameter through the tool for improvement, the variation of PV of 3.247 ~ 1.756 ㎛ was observed in the case of the main mirror. In the case of the sub mirror, PV was 0.673 ~ 0.611 ㎛ (See Table 8).

Main

Pukyung

On the other hand, the improvement tooling pot (including both the main tooling improving tool and the sub-diameter improving tooling tool) manufactured in the above-described improvement tool making and improvement ultra-precision processing step has a support structure in the form of "convex" , All of the side walls corresponding to the height direction of the support structure may be configured to be recessed in the shape of " " in the inward direction.

Further, as described with reference to FIGS. 2 to 4 or 5 to 7, the improvement tool is coupled through a support structure to each of the main or sub-diameter, wherein, in another embodiment, Wherein the support structure comprises a fixed cover which is further protruded in a supporting construction direction and has the same shape as the supporting structure and whose size is larger than the supporting structure, May include a latching claw configuration that engages a side wall formed concavely in the form of a recess.

As a result, even if the improvement tool and the main or minor diameter are fastened by the fastening means as described above, there is a risk that the fastening means is loosened by rotation. However, since the fastening means is completely fixed to the tool for improvement, .

’로 구성되어 상측에 헤드부를 갖고, 상기 헤드부의 상면에는 맞닿는 주경 또는 부경에 닿도록 형성된 돌기가 소정의 형상으로 배열되도록 구성될 수도 있다.According to another designing condition, the outer surface of the groove portion of the support structure into which the above-mentioned fastening means is inserted has a thread 1 corresponding to the thread formed on the inner surface of the groove, and the inner surface has thread 2 corresponding to the thread of the fastening means, And an intermediate member in which the thread 1 and the thread 2 are formed in mutually opposite directions,

'And has a head portion on the upper side, and protrusions formed so as to contact the upper surface of the head portion in contact with the main surface or the minor surface may be arranged in a predetermined shape.

Accordingly, when the fastening means passes through the intermediate member inserted in the groove portion of the support structure through the main or minor diameter while being inserted into the groove portion of the support structure, the intermediate member will try to be exposed upward from the groove portion, As a result, the projections arranged on the upper surface of the head of the intermediate member come into contact with the main or minor diameter, so that even if the influence of the rotational force is transmitted to the main or minor diameter during the improvement process, It will be completely prevented from unwinding.

(6) Aspheric super precision machining step

The aspherical super precision machining step is a step of assembling the main and minor diameters into the tooling holes after the improvement tool making and the improvement super precision machining step are performed and then superposing each of the upper and lower surfaces of the assembled main and sub- to be.

At this time, [Table 9] shows super-precision processing to be an aspherical surface, and [Table 10] shows measurement of aspherical surface with ultra-precision processing by UA3P (Panasoic Inc.).

Main Pukyung

Main Pukyung

As a result of the two-dimensional measurement on the whole surface of the main diameter of 380 mm and the minor diameter of 140 mm in Table 10, the main P-V of 1.9224 μm and the sub-P-V of 0.5803 μm were obtained as shown in [Table 11].

Main Pukyung

[Table 12] shows the results of 3D aspherical shape measurement after separating the main and minor parts from the tool using the USER definition program. As shown in Table 13, the main P-V of 3.2361 ㎛ and the sub-P-V of 0.4798 ㎛ were obtained.

Main Pukyung

Main Pukyung

(7) Gold coating step

The gold coating step is a step of performing gold coating on each of the main and minor diameters manufactured by performing the aspheric surface super fine processing step.

In order to demonstrate the effect of the gold coating step of this step, Applicants have found that the RSA-6061 material has a diameter of 25 to 30 mm and a thickness of 10 mm after the primary processing of the sample in the above- Precision machining was carried out.

At this time, the optimum cutting condition is a cutting speed of 122 m / min, a cutting depth of 3 탆 and a feed rate of 5 mm / min so as to have surface roughness (surface roughness) of Ra 1.4142 nm.

As a result, the surface roughness of RSA-6061 sample after ultra-precision machining as shown in [Table 15] was measured using a local shape measuring device, and Ra 1.4142 nm surface roughness was obtained.

As the local shape measuring instrument, ContourGT-X3 manufactured by BUKER, a surface shape measuring instrument, was used as a non-contact type.

RSA-6061 샘플 초정밀가공 및 샘플 사진

RSA-6061 sample ultra-precision machining and sample pictures

RSA-6061 샘플 국부형상측정 사진 및 측정 결과

RSA-6061 sample local shape measurement photograph and measurement result

As a result of measuring the reflectance of the RSA-6061 sample after gold coating, it was found that a performance of 95% or more was obtained (see Table 16).

RSA-6061 샘플 Gold Coating 반사율 결과 및 샘플 사진

RSA-6061 Sample Gold Coating Reflectance Results and Sample Photos

In order to check whether the gold coating affects the surface roughness of the RSA-6061 sample, the surface roughness was measured again using a local shape measuring instrument. The measurement results showed that the surface roughness Ra of 1.4473 nm was not significantly changed (see Table 17).

RSA-6061 샘플 Gold Coating 후 국부형상측정의 측정 결과

Measurement result of local shape measurement after RSA-6061 sample gold coating

Based on these results, Applicants have completed the preparation of gold-coated primary and secondary diameters as shown in Table 18.

Main Pukyung

Meanwhile, according to one embodiment, the above-mentioned gold coating is formed by coating a gold coating agent on a finished main or minor diameter, then fixing and fixing two opposing points of the main or minor diameter, and then rotating the fixed two points about the axis .

Accordingly, there is an advantage that the coating agent coated on the surface of the main or minor diameter, which is rotated after the gold coating agent is coated, can be uniformly distributed by the centrifugal force.

In addition, the gold coating step may include a coating application step -> heating step -> coating step, in which the coating step is a step of applying the coating agent to the surface of the main or minor diameter, The heating step is a step that proceeds after the application step and heats the main or minor diameter coated with the coating agent at a temperature of 20 to 40 ° C. At this time, the method of applying heat may be performed by various conventional methods, and only the temperature condition may be satisfied. The coating step proceeds after the heating step and is carried out using centrifugal force in the manner described above.

Here, when the heating temperature is lower than 20 ° C, coating with a uniform distribution becomes difficult due to rapid solidification of the coating agent, and it is confirmed that the performance is lowered at the reflectance measured by the procedure according to Table 15, The coating material which is a gold material is melted.

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Claims (1)

A step of manufacturing a tool to fix the main and minor diameters for machining main and minor diameters;
Fixing a main material to a tool made in the tool making step, and then making a main tool;
Fixing the minor diameter material to the tool hole formed in the tool hole manufacturing step, and then manufacturing the minor diameter;
A precise measurement step of confirming that the coupling between the 'tool and the main tool' or the 'tool and the sub-tool' produced through the tool making step, main tool making step and sub-diameter making step is included in the design tolerance;
An improvement tool tip for making an improvement tool for improving the shape of the main or minor diameter through a laser interferometer and performing an improvement using the tool;
An aspheric super precision machining step of machining each of the upper and lower surfaces of the main and minor diameters so as to become an aspherical surface after the improvement tool making and improvement super precision machining steps; And
And a gold coating step of performing gold coating on each of the primary and secondary diameters,
(a) In the step of manufacturing the tool,
A step of manufacturing a main tool for forming an upper tool and a lower tool for fixing the main mirror,
And a step of manufacturing a sub-diameter tool for manufacturing an upper tool and a lower tool for fixing the sub-
(b) fabricating the main mirror and the sub-
Wherein one of the main and minor surfaces of the material has an insert portion protruding in a circular shape on one surface to be a bottom surface and provided with a concave groove therein and a bottom surface precision machining process in which three blade portions are protruded along the protruded circular outer circumference Step,
And an upper surface precision machining step of machining one surface of the material to be an upper surface,
The improvement tooling may include:
Each of the "main tool improving tool" and the "sub-tool improving tool" is formed with a concave groove from one surface, a "convex" type support structure is formed in the inside thereof, Wherein the structure is configured to be fastened to the main or sub-
In the supporting structure, a side wall corresponding to a height direction thereof is concavely formed in the shape of "" in the inside direction,
Wherein the end portion of the fixed cover further protrudes in a supporting construction direction on one side abutting the supporting structure of the main or minor diameter and has the same shape as the supporting structure and the size is larger than the supporting structure, The engagement force of the main or minor diameter and the support structure is improved by including the engagement claw structure which is engaged with the side wall formed concavely in the form of <
(c)
Wherein the heating step comprises heating the main or minor diameter coated with the coating agent at a temperature of 20 to 40 DEG C,
Characterized in that the coating step is carried out by fixing two opposing points of the main or minor diameters and then rotating the two fixed points about the axis so that the coating agent can be evenly coated on the surface of the main or minor diameter by centrifugal force. Method of machining non - reflective optical surfaces.

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