A method for processing a multi-faceted metal reflective mirror

Abstract

This invention discloses a method for fabricating a multifaceted, integrated metallic reflective mirror. The method includes designating a reference reflective mirror among all the reflective mirrors in the multifaceted, integrated metallic reflective mirror assembly. First, the reference reflective mirror is fabricated to a target precision. Then, for the other reflective mirrors, computational holographic compensation interferometry is used to measure the surface shape error of all reflective mirrors in the mirror set simultaneously using a compensator. The surface shape error of each reflective mirror is then converted into a surface shape error relative to the fabricated reference reflective mirror. Finally, each reflective mirror is fabricated individually to ensure that its surface shape error relative to the fabricated reference reflective mirror meets the requirements. This invention aims to achieve improved fabrication of multifaceted, integrated metallic reflective mirrors, reduce assembly and adjustment errors between different reflective mirrors, improve the manufacturing precision of optical systems, and thus enhance the imaging quality of optical systems.

Description

Technical Field

[0001] This invention belongs to advanced manufacturing technology, specifically relating to a processing method for a multi-faceted co-existing metal reflective mirror. Background Technology

[0002] The new generation of optical systems has put forward new requirements such as compact structure, high optical axis stability, long-distance multicolor detection and strong stray light suppression. Traditional optical systems cannot meet the above requirements because: traditional coaxial spherical and aspherical reflection systems have small design freedom and inflexible structure, and cannot simultaneously meet the requirements of small volume, lightweight, no obstruction, aberration correction and stray light suppression. The structure-function integrated multi-freeform optical system can meet the above stringent conditions: (1) the multi-freeform optical system can meet narrower space requirements through more design freedom; (2) the structure-function integrated multi-freeform optical system has no obstruction, and can make fuller use of optical energy; (3) the structure-function integrated multi-freeform optical system, with its irregular structure, does not need an external light shield, and can use the irregular structure of the optical system itself to avoid stray light interference and improve environmental adaptability. Currently, the processing technology for freeform aluminum mirrors cannot meet the new requirements of optical systems. Single-point diamond turning technology is limited by machine tool accuracy and servo axis freedom, and cannot fully meet the processing needs of freeform aluminum mirrors. Moreover, the cutting marks on the machined surface will seriously affect its optical performance. To improve processing accuracy, the aluminum optical mirror surface must be polished after turning. However, aluminum is chemically active and relatively soft, and current processing methods will result in scratches and abrasive embedding, making it difficult to guarantee the processing accuracy of aluminum mirrors. Furthermore, for multi-faceted metal mirrors, existing methods process each mirror independently, which cannot overcome positional errors such as perpendicularity or parallelism. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a processing method for multi-faceted co-functional metal reflective mirrors, thereby reducing the assembly and adjustment errors between different reflective mirrors, improving the manufacturing precision of optical systems, and thus improving the imaging quality of optical systems.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] A method for fabricating a multifaceted, integrated metallic reflective mirror, comprising:

[0006] Step S101: Among all the reflective surfaces of the multi-faceted metal reflective mirror, a reference reflective mirror is specified. The surface shape error of the reference reflective mirror is measured using a compensator by employing computational holographic compensation interferometry.

[0007] Step S102: Process the reference mirror surface according to the surface shape error of the reference mirror surface;

[0008] Step S103: Using computational holographic compensation interferometry, the surface shape error of the reference mirror is measured using a compensator. If the surface shape error meets the requirements, a set of mirrors other than the reference mirror is constructed. Using computational holographic compensation interferometry, the surface shape error of all mirrors in the set is measured at once using a compensator, and the surface shape error of the mirrors is converted into the surface shape error relative to the processed reference mirror. Then, proceed to step S104; otherwise, proceed to step S102 for compensation processing.

[0009] Step S104: Iterate through the set of reflective mirrors and select one reflective mirror as the current reflective mirror;

[0010] Step S105: Process the current reflective mirror based on the surface shape error of the relatively processed reference reflective mirror;

[0011] Step S106: Using computational holographic compensation interferometry, the surface shape error of the current reflecting mirror is measured using a compensator and converted into the surface shape error relative to the processed reference reflecting mirror. If the surface shape error relative to the processed reference reflecting mirror meets the requirements, the process jumps to step S107; otherwise, the process jumps to step S105 to perform the next round of compensation processing.

[0012] Step S107: Determine whether there are still untraversed mirrors in the set of mirrors. If there are still untraversed mirrors, jump to step S104; otherwise, determine that the processing is complete, end and exit.

[0013] Optionally, the multifaceted metal reflector is formed on the same metal blank.

[0014] Optionally, the multifaceted metal reflector is formed by assembling multiple metal blanks, each with a reflector, into a single unit.

[0015] Optionally, specifying a reference mirror in step S101 means specifying the primary mirror of a multi-faceted metal mirror as the reference mirror.

[0016] Furthermore, the present invention also provides a method for manufacturing a multifaceted co-existing metallic reflective mirror, comprising:

[0017] Step S201: Roughly process the metal billet to form a multi-faceted metal reflective mirror.

[0018] Step S202: Use a coordinate measuring machine to measure the geometric dimensions of the multi-faceted metal reflective mirror and its substrate;

[0019] Step S203: Based on a single-point diamond lathe, the reference plane of the multi-faceted co-metal reflective mirror is machined, and with reference to the machined reference plane, the multi-faceted co-metal reflective mirror is machined using the aforementioned machining method.

[0020] Step S204: Based on ion beam processing technology, the aforementioned processing method for the multifaceted co-metal mirror is used to remove the contamination layer of the multifaceted co-metal mirror.

[0021] Step S205: A small grinding head polishing process is adopted, using the aforementioned processing method for multi-faceted co-metal reflective mirrors, to improve the surface accuracy and surface quality of the multi-faceted co-metal reflective mirrors.

[0022] Optionally, step S201 may also include removing residual stress in the metal using a specified method.

[0023] Optionally, the specified method includes one or more of quenching and annealing, vibration, cryogenic treatment, and aging treatment.

[0024] Optionally, after step S203 and before step S204, the multifaceted metal reflective mirror is further shaped using the processing method described above, based on magnetorheological processing technology or ion beam processing technology.

[0025] Optionally, in step S204, when removing the contamination layer of the multifaceted metal mirror, the thickness of the contamination layer removed from each mirror surface of the multifaceted metal mirror is the same.

[0026] Optionally, step S205 may further include coating the multifaceted metal reflective mirror surface.

[0027] Compared with the prior art, the present invention has the following main advantages:

[0028] 1. The processing method of the multi-faceted co-type metal reflective mirror of the present invention can realize the processing of multi-faceted co-type metal reflective mirrors. Multiple metal reflective mirrors are processed on the co-type substrate structure. The multiple mirrors and the substrate are designed as an integral piece using the same material. No assembly and adjustment are required. This can reduce the impact of installation errors between mirrors on the imaging quality of the measurement optical system and eliminate the need for assembly and adjustment.

[0029] 2. The processing method of the multi-faceted metal reflective mirror of the present invention first processes the reference reflective mirror to the target precision, and then processes other reflective mirrors based on the reference reflective mirror. By using computational holographic compensation interferometry technology, the surface shape error of the current reflective mirror is measured by a compensator and converted into the surface shape error relative to the processed reference reflective mirror. The pose error, such as the perpendicularity or parallelism error between other reflective mirrors and the reference reflective mirror, can be converted into the surface shape error between other reflective mirrors and the reference reflective mirror, i.e., the height and low point error of the surface, and compensated for. This can solve the problem of ensuring the perpendicularity or parallelism pose relationship between the primary mirror and the secondary mirror during installation, eliminate the perpendicularity or parallelism pose error, and realize the superposition of the mirror pose error into the surface shape error for consistent form and position error processing. Thus, the surface shape and pose error can be controlled at the nanometer precision level, improving the imaging quality of the optical system.

[0030] 3. After completing the processing of the reference reflective mirror, the present invention includes using a compensator to measure the surface shape error of all reflective mirrors in the reflective mirror set at one time, and converting the surface shape error of the reflective mirror into the surface shape error relative to the processed reference reflective mirror. It can simultaneously measure the surface shape error and pose error of multiple mirrors, with high measurement accuracy and easy compensation processing.

[0031] 4. The processing method of the multi-faceted metal reflective mirror of the present invention does not depend on a specific processing method. It can be applied to advanced processing methods such as single-point diamond lathe, magnetorheological processing, ion beam processing, and small grinding head polishing for high-precision mirror processing. It can simultaneously correct surface shape and positional errors, and complete high-precision, high-surface-quality processing. It has the advantage of good versatility. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the basic process of the method in Embodiment 1 of the present invention.

[0033] Figure 2 This is a schematic diagram of the optical path principle of the multi-faceted metal reflective mirror in Embodiment 1 of the present invention.

[0034] Figure 3 This is a schematic diagram of the basic process of the manufacturing method in Embodiment 2 of the present invention.

[0035] Figure 4 This is a schematic diagram of the basic process of the manufacturing method in Embodiment 3 of the present invention. Detailed Implementation

[0036] Example 1:

[0037] like Figure 1 As shown, the processing method of the multi-faceted co-type metal reflective mirror in this embodiment includes:

[0038] Step S101: Among all the reflective surfaces of the multi-faceted metal reflective mirror, a reference reflective mirror is specified. The surface shape error of the reference reflective mirror is measured using a compensator by employing computational holographic compensation interferometry.

[0039] Step S102: Process the reference mirror surface according to the surface shape error of the reference mirror surface;

[0040] Step S103: Using computational holographic compensation interferometry, the surface shape error of the reference mirror is measured using a compensator. If the surface shape error meets the requirements, a set of mirrors other than the reference mirror is constructed. Using computational holographic compensation interferometry, the surface shape error of all mirrors in the set is measured at once using a compensator, and the surface shape error of the mirrors is converted into the surface shape error relative to the processed reference mirror. Then, proceed to step S104; otherwise, proceed to step S102 for compensation processing.

[0041] Step S104: Iterate through the set of reflective mirrors and select one reflective mirror as the current reflective mirror;

[0042] Step S105: Process the current reflective mirror based on the surface shape error of the relatively processed reference reflective mirror;

[0043] Step S106: Using computational holographic compensation interferometry, the surface shape error of the current reflecting mirror is measured using a compensator and converted into the surface shape error relative to the processed reference reflecting mirror. If the surface shape error relative to the processed reference reflecting mirror meets the requirements, the process jumps to step S107; otherwise, the process jumps to step S105 to perform the next round of compensation processing.

[0044] Step S107: Determine whether there are still untraversed mirrors in the set of mirrors. If there are still untraversed mirrors, jump to step S104; otherwise, determine that the processing is complete, end and exit.

[0045] When using computational holographic compensated interferometry (CGH) with a compensator to measure the surface shape error of a reflecting mirror, the accuracy can reach approximately 10 nm RMS or even lower, which is better than that of a coordinate measuring machine. The compensator in CGH needs to be specially designed and manufactured based on a multi-faceted optical system and measured using a wavefront interferometer. It is used for detecting surface shape and pose errors at various stages of single-point diamond turning, magnetorheology, ion beam machining, and polishing. If the required accuracy is not achieved, compensation processing can be performed.

[0046] It should be noted that the multi-faceted co-type metal reflective mirror is the object to be processed in this embodiment. The multi-faceted co-type metal reflective mirror is formed by processing on the same metal blank, or the multi-faceted co-type metal reflective mirror is formed by assembling multiple metal blanks, each with a reflective mirror, into one piece. Both can be called multi-faceted co-type mirror or structural and functional integrated multi-freeform surface.

[0047] Considering that the primary mirror of a multi-faceted metallic reflective mirror generally has a large area, in this embodiment, specifying a reference reflective mirror in step S101 means specifying the primary mirror of the multi-faceted metallic reflective mirror as the reference reflective mirror, thereby improving the processing accuracy of other reflective mirrors. For example... Figure 2 As shown, as an optional implementation, the multi-faceted metallic reflective mirror in this embodiment includes a primary mirror, a secondary mirror, and a third mirror on the same substrate. Alternatively, two or more reflective mirrors (three mirrors, four mirrors, etc.) can be used as needed. The substrate can be made of aluminum or other metals. The mirror surfaces of the primary mirror, secondary mirror, and third mirror can be spherical, aspherical, freeform, or even other complex curved surfaces.

[0048] In summary, the processing method of the multi-faceted co-type metal reflective mirror in this embodiment can realize the processing of multi-faceted co-type metal reflective mirrors. Multiple metal reflective mirrors are processed on the co-type substrate structure, and the multiple mirrors and the substrate are designed as a whole using the same material. No assembly or adjustment is required, which can reduce the impact of installation errors between mirrors on the imaging quality of the measurement optical system and eliminate the need for assembly and adjustment. This embodiment describes a multi-faceted metal reflective mirror processing method. First, a reference reflective mirror is processed to the target precision. Then, other reflective mirrors are processed based on the reference mirror. By employing computational holographic compensation interferometry, a compensator measures the surface shape error of the current reflective mirror and converts it into a surface shape error relative to the processed reference mirror. This converts the pose errors, such as perpendicularity or parallelism errors between other reflective mirrors and the reference mirror, into surface shape errors, i.e., height and low point errors, for compensation. This method effectively solves the problem of ensuring the perpendicularity or parallelism of the primary and secondary mirrors during installation, eliminating these pose errors. It achieves consistent form and position error processing by superimposing the mirror pose errors into the surface shape errors, thereby controlling the surface shape and pose errors at the nanometer precision level and improving the imaging quality of the optical system. The processing method for multi-faceted metallic reflective mirrors in this embodiment, after completing the processing of the reference reflective mirror, includes using a compensator to measure the surface shape error of all reflective mirrors in the reflective mirror set at once, and converting the surface shape error of the reflective mirrors into the surface shape error relative to the processed reference reflective mirror. This allows for simultaneous measurement of the surface shape error and pose error of multiple mirrors, resulting in high measurement accuracy and easy compensation processing. This processing method for multi-faceted metallic reflective mirrors in this embodiment is not dependent on a specific processing method and is applicable to advanced processing methods such as single-point diamond lathes, magnetorheological machining, ion beam machining, and small grinding head polishing for high-precision mirror processing. It can simultaneously correct surface shape and pose error, achieving high-precision, high-surface-quality processing and possessing the advantage of good versatility. This processing method for multi-faceted metallic reflective mirrors in this embodiment can be used for high-precision manufacturing of multi-faceted metallic reflective mirrors. Other similar metallic reflective mirrors can also be manufactured using this processing method, offering advantages such as high processing accuracy and eliminating the need for adjustment of multiple reflective mirrors.

[0049] Example 2:

[0050] This embodiment is a further application of Embodiment 1.

[0051] like Figure 3 As shown, the manufacturing method of the multifaceted metallic reflective mirror in this embodiment includes:

[0052] Step S201: Roughly process the metal billet to form a multi-faceted metal reflective mirror.

[0053] Step S202: Use a coordinate measuring machine to measure the geometric dimensions of the multi-faceted metal reflective mirror and its substrate;

[0054] Step S203: Based on a single-point diamond lathe, the reference plane of the multifaceted metal reflective mirror is machined, and with reference to the machined reference plane, the multifaceted metal reflective mirror is machined using the machining method of Embodiment 1. In this embodiment, when using a single-point diamond lathe for precision turning, according to the optical system design, if the optical precision imaging is in the infrared band, this type of machine tool is sufficient to meet the requirements; if it is in the visible light band, subsequent machining methods are required.

[0055] Step S204: Based on ion beam processing technology, the processing method of the multi-faceted co-metal mirror surface in Example 1 is used to remove the contamination layer of the multi-faceted co-metal mirror. Ion beam processing can not only remove the contamination layer on the aluminum mirror surface, but also directly reshape it using ion beam. The reshaping process can be carried out directly after single-point diamond turning.

[0056] Step S205 involves employing a small grinding head polishing technique, using the processing method of the multi-faceted metal reflective mirror from Example 1 to improve the surface accuracy and quality of the multi-faceted metal reflective mirror. The small grinding head process employs immersion polishing; to improve surface quality, a uniform polishing method is used to remove a layer from the surface; to improve surface accuracy, the primary mirror is used as a reference mirror and processed to the target accuracy, while the pose and surface errors are superimposed onto the other mirrors for processing.

[0057] As an optional implementation, step S201 of this embodiment further includes using a specified method to remove residual stress in the metal to prevent defects from occurring during processing. The specified method includes one or more of quenching and annealing, vibration, cryogenic treatment, and aging treatment, and the number of repetitions can be specified according to actual needs.

[0058] In step S204 of this embodiment, when removing the contamination layer of the multifaceted metal reflector, the thickness of the contamination layer removed from each reflector surface of the multifaceted metal reflector is the same.

[0059] like Figure 3 As shown, this embodiment further includes coating the multifaceted metal reflective mirror surface after step S205.

[0060] After verification, when using a coordinate measuring machine to measure the geometric dimensions of the multifaceted metal reflective mirror and its substrate in step S202, the accuracy is 1μm+L / 300mm, and the accuracy of interferometry can reach below 10nm RMS.

[0061] Example 3:

[0062] This embodiment is a further improvement on embodiment two.

[0063] like Figure 4 As shown, this embodiment adds a step after step S203 and before step S204 based on embodiment 2: using magnetorheological processing technology or ion beam processing technology, the processing method of the multi-faceted co-metal reflective mirror of embodiment 1 is used to reshape the multi-faceted co-metal reflective mirror.

[0064] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for processing a multifaceted, integrated metallic reflective mirror, characterized in that, include: Step S101: Among all the reflective surfaces of the multi-faceted metal reflective mirror, a reference reflective mirror is specified. The surface shape error of the reference reflective mirror is measured using a compensator by employing computational holographic compensation interferometry. Step S102: Process the reference mirror surface according to the surface shape error of the reference mirror surface; Step S103: Using computational holographic compensation interferometry, the surface shape error of the reference mirror is measured using a compensator. If the surface shape error meets the requirements, a set of mirrors other than the reference mirror is constructed. Using computational holographic compensation interferometry, the surface shape error of all mirrors in the set is measured at once using a compensator, and the surface shape error of the mirrors is converted into the surface shape error relative to the processed reference mirror. Jump to step S104; Otherwise, proceed to step S102 for compensation processing; Step S104: Iterate through the set of reflective mirrors and select one reflective mirror as the current reflective mirror; Step S105: Process the current reflective mirror based on the surface shape error of the relatively processed reference reflective mirror; Step S106: Using computational holographic compensation interferometry, the surface shape error of the current reflecting mirror is measured using a compensator and converted into the surface shape error relative to the processed reference reflecting mirror. If the surface shape error relative to the processed reference reflecting mirror meets the requirements, then proceed to step S107. Otherwise, proceed to step S105 for the next round of compensation processing; Step S107: Determine whether there are still untraversed mirrors in the set of mirrors. If there are still untraversed mirrors, jump to step S104; otherwise, determine that the processing is complete, end and exit.

2. The processing method for a multi-faceted metallic reflective mirror according to claim 1, characterized in that, The multifaceted metal reflective mirror is formed by machining on the same metal blank.

3. The processing method for a multi-faceted metallic reflective mirror according to claim 1, characterized in that, The multifaceted metal reflective mirror is formed by assembling multiple metal blanks, each with a reflective mirror, into a single unit.

4. The processing method for a multi-faceted metallic reflective mirror according to claim 1, characterized in that, In step S101, specifying a reference mirror means specifying the primary mirror of the multi-faceted metal mirror as the reference mirror.

5. A method for manufacturing a multifaceted, integrated metallic reflective mirror, characterized in that, include: Step S201: Roughly process the metal billet to form a multi-faceted metal reflective mirror. Step S202: Use a coordinate measuring machine to measure the geometric dimensions of the multi-faceted metal reflective mirror and its substrate; Step S203: Based on a single-point diamond lathe, the reference plane of the multi-faceted co-metal reflective mirror is machined, and with reference to the machined reference plane, the multi-faceted co-metal reflective mirror is machined using the machining method of any one of claims 1 to 4. Step S204: Based on ion beam processing technology, the processing method of the multifaceted co-metal mirror surface described in any one of claims 1 to 4 is used to remove the contamination layer of the multifaceted co-metal mirror. Step S205: A small grinding head polishing process is adopted, using the processing method of the multi-faceted co-metal reflective mirror as described in any one of claims 1 to 4, to improve the surface shape accuracy and surface quality of the multi-faceted co-metal reflective mirror.

6. The method for manufacturing a multifaceted metallic reflective mirror according to claim 5, characterized in that, Step S201 also includes removing residual stress in the metal using a specified method.

7. The method for manufacturing a multifaceted metallic reflective mirror according to claim 6, characterized in that, The specified method includes one or more of the following: quenching and annealing, vibration, cryogenic treatment, and aging treatment.

8. The method for manufacturing a multifaceted metallic reflective mirror according to claim 5, characterized in that, After step S203 and before step S204, the process further includes using a processing method for the multifaceted co-faceted metal reflective mirror as described in any one of claims 1 to 4, based on magnetorheological processing technology or ion beam processing technology, to reshape the multifaceted co-faceted metal reflective mirror.

9. The method for manufacturing a multifaceted metallic reflective mirror according to claim 5, characterized in that, In step S204, when removing the contamination layer of the multifaceted metal mirror, the thickness of the contamination layer removed from each mirror surface of the multifaceted metal mirror is the same.

10. The method for manufacturing a multifaceted metallic reflective mirror according to claim 5, characterized in that, Step S205 is followed by coating the multifaceted metal reflective mirror surface.

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