CN118950618A - A method for in-situ cleaning of large-aperture optical components by CO2 laser-low-pressure plasma - Google Patents
A method for in-situ cleaning of large-aperture optical components by CO2 laser-low-pressure plasma Download PDFInfo
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- CN118950618A CN118950618A CN202411242098.1A CN202411242098A CN118950618A CN 118950618 A CN118950618 A CN 118950618A CN 202411242098 A CN202411242098 A CN 202411242098A CN 118950618 A CN118950618 A CN 118950618A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B7/00—Cleaning by methods not provided for in a single other subclass or a single group in this subclass
- B08B7/04—Cleaning by methods not provided for in a single other subclass or a single group in this subclass by a combination of operations
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B11/00—Cleaning flexible or delicate articles by methods or apparatus specially adapted thereto
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B13/00—Accessories or details of general applicability for machines or apparatus for cleaning
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B7/00—Cleaning by methods not provided for in a single other subclass or a single group in this subclass
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B7/00—Cleaning by methods not provided for in a single other subclass or a single group in this subclass
- B08B7/0035—Cleaning by methods not provided for in a single other subclass or a single group in this subclass by radiant energy, e.g. UV, laser, light beam or the like
- B08B7/0042—Cleaning by methods not provided for in a single other subclass or a single group in this subclass by radiant energy, e.g. UV, laser, light beam or the like by laser
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Abstract
The invention discloses a method for in-situ composite cleaning of a large-caliber optical element by CO 2 laser-low-pressure plasma, which comprises the following steps: cleaning the polluted optical element by using a CO 2 laser-low-pressure plasma composite cleaning system; designing a CO 2 laser cleaning route, setting laser cleaning parameters, and performing CO 2 laser cleaning on the optical element; setting low-pressure plasma cleaning parameters, and performing low-pressure plasma cleaning on the optical element; the performance parameters of the optical element after pollution, CO 2 laser cleaning and low-pressure plasma cleaning are compared, and the cleaning parameters are optimized to obtain the optimal cleaning parameters of the CO 2 laser-low-pressure plasma in-situ composite cleaning large-caliber optical element. The invention can realize the in-situ high-efficiency nondestructive cleaning of the large-caliber optical element, and effectively solves the problems of easy surface damage and low-pressure plasma cleaning efficiency when the laser is used for cleaning the precise optical element.
Description
Technical Field
The invention belongs to more specifically, the invention relates to a method for cleaning a large-caliber optical element by CO 2 laser-low-pressure plasma in-situ compounding.
Background
In the long-term operation process of large-scale precise complex optical systems such as a synchronous radiation light source (SSRF), extreme ultraviolet lithography (EUV), an international thermonuclear fusion experimental reactor (ITER), a space spacecraft, an inertial confinement fusion device (ICF) and the like, large-caliber optical elements are important components for transmitting, converting, filtering and focusing the light source. In order to ensure the transmission quality of the light source of large-caliber optics, the vacuum state (10 -3-10-6 Pa) is kept in the optical system for a long time. Structural members, sealing rubber rings, lubricating grease and vacuum pumps used in an optical system in a vacuum environment gradually release molecular pollutants to be desorbed and volatilized from the surface into the environment, then gradually diffuse, agglomerate, subside and adsorb the molecular pollutants to the surface of a large-caliber optical element, and after the optical system is operated for a period of time, the optical element forms surface deposition, so that the optical performance of the element is obviously reduced, and meanwhile, the reduction of the quality of a light beam and the enhancement of the field intensity of the surface are further caused due to the change of the surface type of the optical element. Along with the continuous improvement of various performance indexes of a large-scale precise complex optical system, the requirement on the cleanliness of the surface of a large-caliber optical element is more severe, and the running stability of the system is gradually reduced.
At present, clean maintenance of carbon-polluted large-caliber optics is difficult, on one hand, the operation difficulty of an optical element is high in disassembly, transportation, cleaning and installation due to large size, easy surface damage and the like, the time consumption is long, and the operation efficiency of an optical system is seriously reduced. In another aspect, the in-situ cleaning technology needs to meet the requirements of high cleaning efficiency and damage-free cleaning at the same time due to the fact that the space environment in the optical system is complex and limited, the optical element is large in size, the optical surface is easy to damage, and the like. Therefore, students at home and abroad continuously explore in-situ removal means of organic pollutants on the surface of the large-caliber optical element, and creatively propose in-situ cleaning technologies such as laser cleaning, plasma cleaning, ultraviolet-ozone cleaning and the like. The laser cleaning is used as an efficient cleaning mode, and the carbon pollutants on the surface of the optical element can be removed rapidly through heat absorption, but the surface of the optical element is damaged easily through over-cleaning. The plasma cleaning technology is used as a precise cleaning mode, and trace carbon pollutants on the surface of the optical element can be removed through a physical-chemical reaction, but the cleaning efficiency of a large amount of carbon pollutants on the surface of the optical element is low. Although ultraviolet-ozone cleaning has a certain cleaning effect, the cleaning efficiency and the cleaning process are uncontrollable, and the ultraviolet-ozone cleaning is difficult to apply to the surface cleaning of the precision optical element. Therefore, if in-situ cleaning of large-aperture optical systems in large-scale precision complex optical systems can be achieved theoretically by combining the respective advantages of laser cleaning and plasma cleaning, the understanding of such a composite cleaning principle, the design of the method, the selection of parameters, and the planning of the process are very challenging.
Disclosure of Invention
It is an object of the present invention to address at least the above problems and/or disadvantages and to provide at least the advantages described below.
To achieve these objects and other advantages and in accordance with the purpose of the invention, a method for CO 2 laser-low pressure plasma in situ composite cleaning of large aperture optical elements is provided, comprising the steps of:
Preparing an optical element sample, carrying out pollution treatment on the optical element sample, and measuring performance parameters of the optical element before and after pollution; the polluted optical element is arranged in a CO 2 laser-low pressure plasma composite cleaning system, and the calibration of the position of the optical element is realized through the detection of the indication light and a camera;
Step two, designing a CO 2 laser cleaning route, setting laser cleaning parameters, and performing CO 2 laser cleaning on the optical element;
Step three, measuring the performance parameters of the optical element after CO 2 laser cleaning, and comparing the performance parameters with the performance parameters of the optical element after pollution and pollution;
Setting low-pressure plasma cleaning parameters, and performing low-pressure plasma cleaning on the optical element subjected to CO 2 laser cleaning;
Step five, measuring the performance parameters of the optical element after low-pressure plasma cleaning, and comparing the performance parameters with the performance parameters of the optical element after uncontaminated, polluted and CO 2 laser cleaning;
And step six, optimizing the CO 2 laser cleaning parameters in the step two and the low-pressure plasma cleaning parameters in the step five through the comparison of the performance parameters of the optical element in the step three and the step five so as to obtain the optimal cleaning parameters for in-situ composite cleaning of the large-caliber optical element by the CO 2 laser-low-pressure plasma, and performing composite cleaning on the large-caliber optical element according to the optimal cleaning parameters so as to realize the optimal cleaning effect of the large-caliber optical element.
Preferably, the large-caliber optical element is a fused quartz optical element plated with a silicon dioxide antireflection film, the size of the fused quartz optical element is 430mm multiplied by 10mm, and the antireflection wave band of the silicon dioxide antireflection film is 351nm.
Preferably, in the first step, the optical element sample is prepared by using the same substrate and coating process as those of the large-caliber optical element, and the size of the optical element sample is 50mm×50mm×5mm.
Preferably, in the first step, the pollution treatment is to simulate a heavy pollution state of the surface of the optical element after long-term operation in a high vacuum environment, and the specific method comprises the following steps: the optical element is placed above a beaker filled with dibutyl phthalate, the volatilization of pollutants is accelerated by heating the beaker to 100 ℃, the pollutants are adsorbed on the surface of the optical element, the two sides of the optical element are polluted for 40s, and the optical element is kept stand for 6h after the pollution.
Preferably, the performance parameters of the optical element include: transmittance, surface wettability, and microtopography.
Preferably, the method for measuring the performance parameter of the optical element comprises the following steps: the transmittance is measured by a spectrophotometer, the wettability of the surface is measured by a contact angle tester, and the microscopic morphology is measured by an atomic force microscope.
Preferably, in the second step, the CO 2 laser cleaning route is as follows: routing a zigzag path on the surface of the optical element; the laser cleaning parameters are as follows: the laser beam is a first-order diffraction beam, the pulse width is 5-50 mu s, the working frequency is 2000Hz, the peak power is 50W, the moving speed is 80-100 mm/s, and the light spot overlapping rate is 0.3-0.7.
Preferably, in the fourth step, the low pressure plasma cleaning parameters are: the discharge frequency is 10-30 kHz, the power is 70-80W, and the cleaning time is 2-5 min.
Preferably, the CO 2 laser-low pressure plasma composite cleaning system includes:
The front side of the laser transmission pipeline is detachably provided with a sealing window, a sealing environment is formed by surrounding the laser transmission pipeline and the sealing window, a clamping groove for installing and fixing an optical element is arranged between the laser transmission pipeline and the sealing window, the laser transmission pipeline is arranged on a two-dimensional moving platform, and the laser transmission pipeline moves left and right and up and down through the two-dimensional moving platform;
A CCD camera arranged opposite to the laser transmission pipeline so as to be opposite to the front surface of the optical element;
a scanning galvanometer arranged opposite to the laser transmission pipeline so as to be opposite to the front surface of the optical element;
The He-Ne laser is used for outputting visible light, and the visible light sequentially passes through the total reflection mirror, the spectroscope, the total reflection mirror, the beam expander and the scanning galvanometer and is focused on the surface of the optical element to be used as indicating light;
The CO 2 laser is used for outputting pulse laser, and the pulse laser sequentially passes through the acousto-optic modulator, the spectroscope, the total reflection mirror, the beam expander and the scanning galvanometer, is focused on the surface of the optical element, and carries out CO 2 laser cleaning on the optical element;
The acousto-optic modulator is connected with the signal generator and used for converting pulse laser output by the CO 2 laser;
four plasma discharge electrodes which are circumferentially arranged on four sides of the sealing window;
the low-pressure plasma control system is connected with the laser transmission pipeline;
a low-voltage plasma discharge system connected to the four plasma discharge electrodes;
The CO 2 laser cleaning control system is respectively connected with a CCD camera, a two-dimensional moving platform, a scanning galvanometer, a He-Ne laser, a signal generator and a CO 2 laser.
Preferably, the CO 2 laser outputs pulse laser with the wavelength of 10.6 μm, the laser beam is Gaussian, the maximum output power is 100W, and the working frequency is 2000Hz.
In the invention, the high vacuum environment is 10 -3～10-6 Pa, the carbon pollutant adopts dibutyl phthalate, the dibutyl phthalate has an aromatic hydrocarbon structure and alkane branched chains, and the physical and chemical properties of the pollutant are generally representative; the simulation of the heavy pollution state of the surface of the optical element is carried out by heating a beaker containing carbon pollutants, and the molecular pollutants can be rapidly diffused on the surface of the optical element to form a uniform carbon pollutant layer; the optical element cleaned by the CO 2 laser is required to be placed in a clean sample box for standing for 6 hours, carbon pollutants remained on the surface of the optical element are enabled to be freely diffused and reach an equilibrium state again, then the optical element is installed in a clamping groove on a laser transmission pipeline again, and the optical element is locked through a limiting structure in the installation process, so that the same installation position of the optical element is achieved each time.
The invention at least comprises the following beneficial effects: according to the method for in-situ composite cleaning of the large-caliber optical element by the CO 2 laser-low-pressure plasma, disclosed by the invention, organic pollutants on the surface of the optical element are roughly cleaned through the heat absorption effect of the optical element on CO 2 laser, and then the surface of the optical element is finely cleaned through the physicochemical effect of the low-pressure plasma and the organic pollutants, so that the removal efficiency of the organic pollutants on the surface of the large-caliber optical element is improved, and the risk of damage to the surface of the optical element is avoided. The compound cleaning method can realize the in-situ high-efficiency nondestructive cleaning of the large-caliber optical element, is not influenced by the surface, size and surface film material of the optical element, effectively solves the problems of easy surface damage and low-pressure plasma cleaning efficiency when the laser cleans the precise optical element, provides an active cleaning method for the in-situ cleaning maintenance of the large-caliber optical element in a large precise complex optical system, and ensures the long-term high-efficiency stable operation of the optical system.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.
Drawings
FIG. 1 is a schematic top view of a CO 2 laser-low pressure plasma hybrid cleaning system according to the present invention;
FIG. 2 is a road map of the surface of a CO 2 laser cleaned optical element;
FIG. 3 shows the peak transmittance at 351nm of an optical element under different conditions in the invention;
FIG. 4 shows the surface wettability of an optical element in different states according to the present invention;
FIG. 5 shows the microscopic morphology of an optical element in different states according to the present invention;
In the figure, a 1-optical element, a 2-CO 2 laser cleaning control system, a 3-CCD camera, a 4-two-dimensional moving platform, a 5-scanning galvanometer, a 6-He-Ne laser, a 7-total reflection mirror, an 8-spectroscope, a 9-total reflection mirror, a 10-beam expander, a 11-signal generator, a 12-CO 2 laser, a 13-acousto-optic modulator, a 14-plasma discharge electrode, a 15-laser transmission pipeline, a 16-low-voltage plasma control system, a 17-low-voltage plasma discharge system and an 18-sealed window.
Detailed Description
The present invention is described in further detail below with reference to the drawings to enable those skilled in the art to practice the invention by referring to the description.
It will be understood that terms, such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.
FIG. 1 shows a CO 2 laser-low pressure plasma hybrid cleaning system of the present invention, comprising:
The front side of the laser transmission pipeline 15 is detachably provided with a sealing window 18, a sealing environment is formed by surrounding the laser transmission pipeline and the sealing window 18, a clamping groove for installing and fixing the optical element 1 is arranged between the laser transmission pipeline 15 and the sealing window 18, the laser transmission pipeline 15 is connected with a two-dimensional moving platform 4, and the laser transmission pipeline 15 moves left and right and up and down through the two-dimensional moving platform 4;
a CCD camera 3 disposed opposite to the laser transmission pipe 15 so as to be opposed to the front surface of the optical element 1;
a scanning galvanometer 5 which is disposed opposite to the laser transmission pipe 15 so as to be opposed to the front surface of the optical element 1;
He-Ne laser 6 for outputting visible light, which is focused on the surface of optical element 1 via total reflection mirror 7, beam splitter 8, total reflection mirror 9, beam expander 10 and scanning galvanometer 5;
The CO 2 laser 12 is used for outputting pulse laser, and the pulse laser sequentially passes through the acousto-optic modulator 13, the spectroscope 8, the total reflection mirror 9, the beam expander 10 and the scanning galvanometer 5 and is focused on the surface of the optical element 1;
An acousto-optic modulator 13 connected to the signal generator 11;
four plasma discharge electrodes 14 disposed around four sides of the sealing window 18;
a low-pressure plasma control system 16 connected to the laser transmission pipe 15;
a low-voltage plasma discharge system 17 connected to the four plasma discharge electrodes 14;
The CO 2 laser cleaning control system 2 is respectively connected with the CCD camera 3, the two-dimensional moving platform 4, the scanning galvanometer 5, the He-Ne laser 6, the signal generator 11 and the CO 2 laser 12.
Working principle:
(1) CO 2 laser cleaning: the polluted optical element 1 is arranged in a clamping groove on the laser transmission pipeline 15 and is locked by a limiting structure; the relative positions of all components are reset through the automatic initialization of the CO 2 laser cleaning control system 2; the signal generator 11 and the CO 2 laser 12 are signaled by the CO 2 laser cleaning control system 2, the peak value of the pulse laser waveform output by the CO 2 laser 12 is deflected into a first-order diffraction beam by the acousto-optic modulator 13, The light enters the scanning galvanometer 5 after passing through the spectroscope 8, the total reflection mirror 9 and the beam expander 10, and is focused on the surface of the optical element 1; The CO 2 laser cleaning control system 2 is used for giving signals to the He-Ne laser 6, outputting visible light, sequentially passing through the total reflecting mirror 7, the spectroscope 8, the total reflecting mirror 9 and the beam expander 10, then entering the scanning vibrating mirror 5, focusing on the surface of the optical element 1, measuring the coaxiality of two beams of light at the outlet of the scanning vibrating mirror 5, and carrying out beam position adjustment through the total reflecting mirror 7 to ensure the coaxiality of the two beams of light, wherein the visible light output by the He-Ne laser 6 is used as indicating light, namely, the visible light is used for replacing CO 2 laser (main laser) when the optical path adjustment is carried out, The damage to the surface of the optical element caused by the continuous irradiation of the main laser in the debugging process is avoided, the CCD camera 3 is used for photographing and imaging, the position of the indicating light on the surface of the optical element 1 in the field of view is observed in a computer display, and the CO 2 laser is output for experiment after the debugging is finished, so that the coaxiality of two beams of light needs to be ensured as the substitute light; The CCD camera 3 is turned on through the CO 2 laser cleaning control system 2, the coordinate position of the optical element 1 is confirmed, and the two-dimensional moving platform 4 is controlled by the CO 2 laser cleaning control system 2 to move the optical element 1 mounted on the laser transmission pipeline 15 to a cleaning origin; a cleaning route is designed in the CO 2 laser cleaning control system 2, the moving speed and the light spot overlapping rate are set, a laser transmission pipeline 15 provided with the optical element 1 is moved through a two-dimensional moving platform 4, and scanning cleaning is carried out on the surface of the optical element 1 according to the cleaning route from a cleaning origin;
(2) Low pressure plasma cleaning: after CO 2 is subjected to laser cleaning, a vacuum chamber is formed by bolting through a sealing window 18 and a laser transmission pipeline 15 to realize environmental sealing, a low-pressure plasma control system 16 is started, vacuum is pumped to a set vacuum degree, clean air is used as an air source, discharge frequency, power and cleaning time are set, four plasma discharge electrodes 14 are connected through a low-pressure plasma discharge system 17 to discharge, plasma is generated, and low-pressure plasma cleaning is performed.
In the following embodiment, a typical fused quartz optical element coated with a silica antireflection film in a large-scale precise complex optical system is taken as a research object, the heavy pollution state of the surface of the optical element after long-term operation in a high vacuum environment is simulated, and the method for in-situ composite cleaning of the large-caliber optical element by using the CO 2 laser-low-pressure plasma is performed with offline verification.
In the following examples, the transmittance, surface wettability and microscopic morphology of the optical element before and after contamination were characterized, reflecting the optical performance, surface cleanliness and damage condition of the optical element, respectively.
In the following embodiments, the contaminated optical element is put into a CO 2 laser-low pressure plasma composite cleaning system to be cleaned, and the transmittance, the surface wettability and the microscopic morphology of the cleaned optical element are characterized to evaluate the composite cleaning technical effect of the invention; wherein, the large-caliber optical element (430 mm multiplied by 10 mm) is replaced by a small-size optical element (50 mm multiplied by 5 mm) prepared by the same process, so that the optical element is convenient to detach for offline characterization after cleaning, and the tested data are statistically averaged.
Examples
A method for in-situ compound cleaning of a large-caliber optical element by CO 2 laser-low-pressure plasma comprises the following steps:
firstly, placing a fused quartz substrate (50 mm multiplied by 5 mm) in an ultrasonic cleaning tank for surface cleaning treatment, and placing the cleaned fused quartz substrate in a hundred-grade cleaning room for natural airing;
Secondly, placing the dried fused quartz substrate in sol-gel liquid, plating a silicon dioxide antireflection film on the substrate by adopting a pulling method, wherein the antireflection wave band of the silicon dioxide antireflection film is 351nm to obtain an optical element, firstly placing the optical element in a sealed container with ammonia water for aftertreatment for 24 hours, then taking out the optical element, and then placing the optical element in a sealed container with hexamethyldisilazane for aftertreatment for 24 hours; wherein, a beaker is used for filling 300mL of ammonia water or hexamethyldisilazane into a sealed container;
Step three, the transmittance of the optical element after treatment is tested by a spectrophotometer, the transmittance reaches 99.9 percent and meets the use standard, and the wettability and the microscopic morphology of the surface of the optical element are tested by a contact angle tester and an atomic force microscope;
fourth, organic pollution is carried out on the optical element which accords with the use standard by adopting a fumigation method: placing an optical element above a beaker filled with dibutyl phthalate, accelerating volatilization of pollutants by heating the beaker to 100 ℃ and adsorbing the pollutants on the surface of the optical element so as to simulate a heavy pollution state of the surface of the optical element after long-term operation in a high vacuum environment, wherein both sides of the optical element are polluted for 40s, standing for 6h after pollution, obtaining the polluted optical element, and then testing the transmittance and the surface wettability and the microscopic morphology;
Step five, the polluted optical element 1 is arranged in a clamping groove of a laser transmission pipeline 15 of the CO 2 laser-low pressure plasma composite cleaning system and is locked through a limiting structure; the relative positions of all components are reset through the automatic initialization of the CO 2 laser cleaning control system 2;
Step six, the CO 2 laser cleaning control system 2 controls the He-Ne laser 6 to emit visible light with the wavelength of 632.8nm as indication light, the visible light passes through the total reflection mirror 7, the spectroscope 8 and the total reflection mirror 9, the visible light enters the scanning galvanometer 5 after being expanded by the beam expander 10 and is irradiated onto the surface of the polluted optical element, the CCD camera 3 is used for photographing and imaging, the relative position of the indication light is determined, and the position of the indication light on the surface of the optical element in a view field is observed in a computer display;
Step seven, a signal generator 11 and a CO 2 laser 12 are given signals through a CO 2 laser cleaning control system 2, the peak value of a pulse laser waveform output by the CO 2 laser 12 is deflected into a first-order diffraction beam through an acousto-optic modulator 13, CO 2 laser with the pulse width of 50 mu s, the frequency of 2000Hz and the peak power of 50W is obtained, the CO 2 laser enters a scanning galvanometer 5 after passing through a spectroscope 8, a total reflection mirror 9 and a beam expander 10, and the Gaussian light spot focused on the surface of an optical element is calculated to have the effective diameter of 74 mu m according to 1/e 2; the CO 2 laser outputs pulse laser with the wavelength of 10.6 mu m, the laser beam is Gaussian, the maximum output power of the CO 2 laser is 100W, and the working frequency is 2000Hz;
Step eight, the CO 2 laser 12 and the He-Ne laser 6 are simultaneously signaled by the CO 2 laser cleaning control system 2, the coaxiality of two beams of light is measured at the outlet of the scanning galvanometer 5, and the beam position is adjusted by the total reflection mirror 7 so as to ensure the coaxiality of the two beams of light; the visible light output by the He-Ne laser 6 is used as an indication light to replace CO 2 laser (main laser) when the optical path is debugged, so that the damage to the surface of an optical element caused by continuous irradiation of the main laser in the debugging process is avoided;
Step nine, turning on a CCD camera 3 through a CO 2 laser cleaning control system 2, confirming the coordinate position of the optical element 1, and controlling a two-dimensional moving platform 4 to move the optical element 1 mounted on a laser transmission pipeline 15 to a cleaning origin through the CO 2 laser cleaning control system 2; the CO 2 laser cleaning optical element 1 surface route is as shown in figure 2, the cleaning route is designed in the CO 2 laser cleaning control system 2, the laser transmission pipeline 15 provided with the optical element 1 is moved by the two-dimensional moving platform 4, so that laser starts to walk a 'zigzag' route on the optical element surface from a cleaning origin, the moving speed is set to 90mm/s, the light spot overlapping rate is 0.5, and the full-caliber scanning cleaning is realized;
Step ten, performing transmittance, surface wettability and microscopic morphology characterization on the optical element subjected to CO 2 laser cleaning, comparing the optical element with uncontaminated and polluted optical element performance parameters, and judging the CO 2 laser cleaning degree;
eleventh, after CO 2 is cleaned by laser, the vacuum chamber is formed by bolting the sealing window 18 and the laser transmission pipeline 15 to realize environmental sealing, the low-pressure plasma control system 16 is started, the sealing environment is pumped to 20Pa, clean air is adopted as an air source, the discharge frequency is set to 20kHz, the power is set to 75W, the four plasma discharge electrodes 14 are connected by the low-pressure plasma discharge system 17 to discharge, plasma is generated, and the optical element is cleaned for 3 minutes;
And step twelve, performing transmittance, surface wettability and microscopic morphology characterization on the optical element 1 after low-pressure plasma cleaning, comparing the transmittance, the surface wettability and the microscopic morphology characterization with the uncontaminated and polluted optical element performance parameters after CO 2 laser cleaning, and judging the low-pressure plasma cleaning degree.
Fig. 3 shows the peak transmittance of the optical element at 351nm in different states in this embodiment, the transmittance of the uncontaminated optical element reaches 99.9%, the transmittance of the optical element after carbon contamination rapidly drops to 95.7%, and the transmission efficiency of the light beam is severely reduced. After the CO 2 laser cleaning, the transmittance of the optical element is recovered to 99.4%, and although the transmittance of the optical element is remarkably recovered, trace carbon pollutants still remain on the surface, so that the use requirement cannot be met. Finally, the carbon pollutants on the surface of the optical element are thoroughly removed after the low-pressure plasma cleaning is performed on the basis of CO 2 laser cleaning, and the transmittance is completely recovered.
Fig. 4 shows the surface wettability of the optical element in different states in this embodiment, where a large number of silane groups exist on the surface of the optical element after post-treatment, the surface water contact angle reaches 119.1 °, and hydrocarbon chemical bonds of alkane molecules in carbon pollution are hydrophobic groups, so that the hydrophobic property of the surface of the polluted optical element is further increased, and the surface water contact angle is increased to 124.0 °. The carbon contaminants on the surface of the optical element after CO 2 laser cleaning are mostly removed, and the surface water contact angle is reduced to 66.2 ° with the removal of part of the silicon methyl groups. After the surface of the optical element is further treated by the low-pressure air plasma, carbon pollutants are thoroughly removed, a large number of hydrophilic groups such as carboxyl groups, hydroxyl groups and the like are formed with the optical element, and the surface water contact angle is reduced to 11.6 degrees. Therefore, the degree of surface contaminant removal can be qualitatively determined by the change in the surface water contact angle of the optical element.
Fig. 5 shows the microscopic morphology of the optical element in different states in the present embodiment, and the surface chemical film of the uncontaminated optical element has a loose porous structure, the surface roughness value is only 1.373nm, the whole peak of the surface protrusion becomes round after carbon contamination, and the roughness value is raised to 5.488nm. The surface pollutants of the optical element are mostly removed after CO 2 laser cleaning, the surface is not damaged, the roughness value is recovered to 4.052nm, the carbon pollution on the surface of the optical element is thoroughly removed after low-pressure air plasma cleaning, the loose porous structure on the surface of the optical element is not damaged, and the roughness value is recovered to 1.391nm.
In summary, through the comparative analysis of transmittance, surface wettability and microscopic morphology, it can be seen that the cleaning effect of the cleaning parameters of the embodiment is excellent, and the cleaning process is adopted to clean the large-caliber optical element, so that the high-efficiency nondestructive cleaning of the large-caliber optical element can be realized.
Although embodiments of the present invention have been disclosed above, it is not limited to the details and embodiments shown and described, it is well suited to various fields of use for which the invention would be readily apparent to those skilled in the art, and accordingly, the invention is not limited to the specific details and illustrations shown and described herein, without departing from the general concepts defined in the claims and their equivalents.
Claims (10)
1. The method for in-situ composite cleaning of the large-caliber optical element by using the CO 2 laser-low-pressure plasma is characterized by comprising the following steps of:
Preparing an optical element sample, carrying out pollution treatment on the optical element sample, and measuring performance parameters of the optical element before and after pollution; the polluted optical element is arranged in a CO 2 laser-low pressure plasma composite cleaning system, and the calibration of the position of the optical element is realized through the detection of the indication light and a camera;
Step two, designing a CO 2 laser cleaning route, setting laser cleaning parameters, and performing CO 2 laser cleaning on the optical element;
Step three, measuring the performance parameters of the optical element after CO 2 laser cleaning, and comparing the performance parameters with the performance parameters of the optical element after pollution and pollution;
Setting low-pressure plasma cleaning parameters, and cleaning the optical element by the low-pressure plasma;
Step five, measuring the performance parameters of the optical element after low-pressure plasma cleaning, and comparing the performance parameters with the performance parameters of the optical element after uncontaminated, polluted and CO 2 laser cleaning;
And step six, optimizing the CO 2 laser cleaning parameters in the step two and the low-pressure plasma cleaning parameters in the step five through comparing the performance parameters of the optical element in the step three and the step five so as to obtain the optimal cleaning parameters for in-situ composite cleaning of the large-caliber optical element by the CO 2 laser-low-pressure plasma.
2. The method for in-situ composite cleaning of a large-caliber optical element by using CO 2 laser-low-pressure plasma as claimed in claim 1, wherein the large-caliber optical element is a fused quartz optical element plated with a silicon dioxide antireflection film, the size of the fused quartz optical element is 430mm multiplied by 10mm, and the antireflection band of the silicon dioxide antireflection film is 351nm.
3. The method for in-situ cleaning of large-caliber optical elements by using CO 2 laser-low pressure plasma as claimed in claim 2, wherein in the first step, the optical element sample is prepared by adopting a substrate and a coating process which are the same as those of the large-caliber optical element, and the size of the optical element sample is 50mm multiplied by 5mm.
4. The method for in-situ composite cleaning of a large-caliber optical element by using CO 2 laser-low pressure plasma according to claim 1, wherein in the first step, the pollution treatment is to simulate the heavy pollution state of the surface of the optical element after long-term operation in a high vacuum environment, and the specific method comprises the following steps: the optical element is placed above a beaker filled with dibutyl phthalate, the volatilization of pollutants is accelerated by heating the beaker to 100 ℃, the pollutants are adsorbed on the surface of the optical element, the two sides of the optical element are polluted for 40s, and the optical element is kept stand for 6h after the pollution.
5. The method for CO 2 laser-low pressure plasma in-situ composite cleaning of large aperture optical components of claim 1, wherein the performance parameters of the optical components include: transmittance, surface wettability, and microtopography.
6. The method for in-situ composite cleaning of a large-caliber optical element by using a CO 2 laser-low-pressure plasma as claimed in claim 5, wherein the method for measuring the performance parameters of the optical element is as follows: the transmittance is measured by a spectrophotometer, the wettability of the surface is measured by a contact angle tester, and the microscopic morphology is measured by an atomic force microscope.
7. The method for CO 2 laser-low pressure plasma in-situ composite cleaning of large caliber optical element as claimed in claim 1, wherein in the second step, the CO 2 laser cleaning route is as follows: routing a zigzag path on the surface of the optical element; the laser cleaning parameters are as follows: the laser beam is a first-order diffraction beam, the pulse width is 5-50 mu s, the working frequency is 2000Hz, the peak power is 50W, the moving speed is 80-100 mm/s, and the light spot overlapping rate is 0.3-0.7.
8. The method for CO 2 laser-low pressure plasma in-situ composite cleaning of large caliber optical element as claimed in claim 1, wherein in the fourth step, the low pressure plasma cleaning parameters are: the discharge frequency is 10-30 kHz, the power is 70-80W, and the cleaning time is 2-5 min.
9. The method for CO 2 laser-low pressure plasma in-situ composite cleaning of large diameter optical components as claimed in claim 1, wherein said CO 2 laser-low pressure plasma composite cleaning system comprises:
The front side of the laser transmission pipeline is detachably provided with a sealing window, a sealing environment is formed by surrounding the laser transmission pipeline and the sealing window, a clamping groove for installing and fixing an optical element is arranged between the laser transmission pipeline and the sealing window, the laser transmission pipeline is arranged on a two-dimensional moving platform, and the laser transmission pipeline moves left and right and up and down through the two-dimensional moving platform;
A CCD camera arranged opposite to the laser transmission pipeline so as to be opposite to the front surface of the optical element;
a scanning galvanometer arranged opposite to the laser transmission pipeline so as to be opposite to the front surface of the optical element;
The He-Ne laser is used for outputting visible light, and the visible light sequentially passes through the total reflection mirror, the spectroscope, the total reflection mirror, the beam expander and the scanning galvanometer and is focused on the surface of the optical element to be used as indicating light;
The CO 2 laser is used for outputting pulse laser, and the pulse laser sequentially passes through the acousto-optic modulator, the spectroscope, the total reflection mirror, the beam expander and the scanning galvanometer, is focused on the surface of the optical element, and carries out CO 2 laser cleaning on the optical element;
The acousto-optic modulator is connected with the signal generator and used for converting pulse laser output by the CO 2 laser;
four plasma discharge electrodes which are circumferentially arranged on four sides of the sealing window;
the low-pressure plasma control system is connected with the laser transmission pipeline;
a low-voltage plasma discharge system connected to the four plasma discharge electrodes;
The CO 2 laser cleaning control system is respectively connected with a CCD camera, a two-dimensional moving platform, a scanning galvanometer, a He-Ne laser, a signal generator and a CO 2 laser.
10. The method for in-situ composite cleaning of large-caliber optical elements by using CO 2 laser-low-pressure plasma as claimed in claim 9, wherein the CO 2 laser outputs pulse laser with the wavelength of 10.6 μm, the laser beam is Gaussian, the maximum output power is 100W, and the working frequency is 2000Hz.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN120446205A (en) * | 2025-07-14 | 2025-08-08 | 中国工程物理研究院激光聚变研究中心 | A method for evaluating outgassing and dust generation from structural materials in continuous laser systems |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20020003411A (en) * | 2000-06-21 | 2002-01-12 | 최승락 | Method cleaning Wafer using Laser and Remote Plasma |
| US20030106881A1 (en) * | 2001-12-07 | 2003-06-12 | Jong-Myong Lee | Dry surface cleaning apparatus |
| JP2004267951A (en) * | 2003-03-11 | 2004-09-30 | Nikon Corp | Cleaning device and cleaning method |
| CN103394490A (en) * | 2008-09-17 | 2013-11-20 | 株式会社日立高新技术 | Device and method for cleaning organic electro luminescence (EL) mask |
| CN106683716A (en) * | 2016-12-09 | 2017-05-17 | 中国科学院合肥物质科学研究院 | Integrated cleaning platform of tokamak first mirror |
| KR20180138110A (en) * | 2017-06-20 | 2018-12-28 | 주식회사 다원시스 | Mask cleaning apparatus and mask cleaning method |
| CN111871967A (en) * | 2020-06-30 | 2020-11-03 | 中国科学院理化技术研究所 | Laser cleaning equipment |
-
2024
- 2024-09-05 CN CN202411242098.1A patent/CN118950618A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20020003411A (en) * | 2000-06-21 | 2002-01-12 | 최승락 | Method cleaning Wafer using Laser and Remote Plasma |
| US20030106881A1 (en) * | 2001-12-07 | 2003-06-12 | Jong-Myong Lee | Dry surface cleaning apparatus |
| JP2004267951A (en) * | 2003-03-11 | 2004-09-30 | Nikon Corp | Cleaning device and cleaning method |
| CN103394490A (en) * | 2008-09-17 | 2013-11-20 | 株式会社日立高新技术 | Device and method for cleaning organic electro luminescence (EL) mask |
| CN106683716A (en) * | 2016-12-09 | 2017-05-17 | 中国科学院合肥物质科学研究院 | Integrated cleaning platform of tokamak first mirror |
| KR20180138110A (en) * | 2017-06-20 | 2018-12-28 | 주식회사 다원시스 | Mask cleaning apparatus and mask cleaning method |
| CN111871967A (en) * | 2020-06-30 | 2020-11-03 | 中国科学院理化技术研究所 | Laser cleaning equipment |
Non-Patent Citations (1)
| Title |
|---|
| 李绪平;祖小涛;袁晓东;蒋晓东;吕海兵;郑万国;唐灿;李珂;向霞;郭袁俊;徐世珍;袁兆林;: "CO_2激光和等离子体清洗提高石英基片损伤阈值", 强激光与粒子束, no. 10, 15 October 2007 (2007-10-15), pages 1739 - 1743 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN120446205A (en) * | 2025-07-14 | 2025-08-08 | 中国工程物理研究院激光聚变研究中心 | A method for evaluating outgassing and dust generation from structural materials in continuous laser systems |
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