Reflector surface hydrophobic micro-nano structure inscribing device and method based on deep ultraviolet laser

Abstract

The invention discloses a reflector surface hydrophobic micro-nano structure inscribing device and method based on deep ultraviolet laser, and the device comprises a first light source which is used for providing a white light source; the second light source is used for providing a laser source, and the laser source is deep ultraviolet laser; the laser scanning module comprises a first piezoelectric control beam splitter, a second beam splitter and a first piezoelectric deflection mirror; the detector is used for acquiring the white light source reflected by the reflector to be etched from the second beam splitter and detecting imaging data and reflectivity of the white light source according to the white light source; the photoetching objective lens is used for focusing the white light source and the laser source to the surface of the reflector to be etched; and the base is used for bearing the reflector to be etched. According to the invention, accurate inscribing can be realized by monitoring and adjusting the inscribing process in real time.

Description

Technical Field

[0001] The present invention relates to the technical field of surface functionalization processing of optical devices, and in particular to a device and method for writing hydrophobic micro-nano structures on the surface of a reflector based on deep ultraviolet laser. Background Art

[0002] At present, there are mainly three methods for engraving hydrophobic micro-nano structures on the surface of reflector coatings: hydrophobic coating, chemical etching and traditional laser processing. Among them, the hydrophobic coating method requires spraying of fluorine-containing polymers or nano-silicon dioxide coatings, which are easy to wear and the reflectivity decreases after long-term exposure (the coating thickness causes light scattering). The chemical etching method requires strong acid treatment of the coating surface, which destroys the structure of the reflective layer and causes a significant decrease in reflectivity. The infrared or visible light laser (such as 1064nm) used in traditional laser processing has a significant thermal effect when processing the coating, which can easily cause coating ablation, oxidation or substrate damage.

[0003] Therefore, a completely new device and process are urgently needed to overcome the related defects of the current technology. Summary of the invention

[0004] In view of this, the first object of the present invention is to provide a device for writing hydrophobic micro-nano structures on the surface of a reflector based on deep ultraviolet laser, which can achieve precise writing by real-time monitoring of the writing process and making adjustments.

[0005] In order to achieve the above object, the technical solution of the present invention is: A device for writing hydrophobic micro-nanostructure on the surface of a reflector based on deep ultraviolet laser, comprising: A first light source, used to provide a white light source; A second light source is used to provide a laser source, wherein the laser source is a deep ultraviolet laser; The laser scanning module comprises a first piezoelectric controlled beam splitter and a first piezoelectric deflection mirror; wherein the first piezoelectric deflection mirror is used to transmit the laser source to the first piezoelectric controlled beam splitter; and the first piezoelectric controlled beam splitter is used to transmit the white light source and the laser source to the second beam splitter; A second beam splitter, used to transmit the white light source and the laser source to the photolithography objective lens, and transmit the white light source reflected by the reflector to be engraved to the detector; A detector, used for acquiring the white light source reflected by the reflector to be engraved from the second beam splitter and detecting its imaging data and reflectivity accordingly; A photolithography objective lens, used to focus the white light source and the laser source onto the surface of the reflector to be engraved; and a base for carrying the reflector to be engraved.

[0006] Preferably, it also includes a laser stabilization module, which includes a second piezoelectric deflection mirror and a second piezoelectric deflection mirror; the second piezoelectric deflection mirror and the second piezoelectric deflection mirror are used to sequentially transfer the laser source emitted from the second light source to the first piezoelectric deflection mirror.

[0007] Preferably, a pinhole plate is further arranged between the first piezoelectric controlled beam splitter and the white light source.

[0008] Preferably, the detector comprises a CCD camera and a spectrometer.

[0009] Preferably, the base adopts a six-axis displacement base.

[0010] The second object of the present invention is to provide a method for writing hydrophobic micro-nano structures on the surface of a reflector based on deep ultraviolet laser, which can achieve precise writing by real-time monitoring of the writing process and making adjustments.

[0011] In order to achieve the above object, the technical solution of the present invention is: A method for writing a hydrophobic micro-nano structure on a reflector surface based on a deep ultraviolet laser is implemented based on the above-mentioned writing device, comprising: S1, use a plasma cleaning machine to treat the coated surface of the reflector to be engraved for T1 time, and then fix it on the six-axis displacement base; S2, positioning an initial processing area on the reflector to be engraved by using a first light source; S3, adjusting each piezoelectric deflection mirror so that the spot of the laser source coincides with the initial processing area; S4, controlling the first piezoelectric controlled beam splitter, the first piezoelectric deflection mirror and the photolithography objective lens to control the laser source to write honeycomb pits on the coating surface; S5, judging the uniformity of the honeycomb pits based on the imaging data output by the CCD camera, and deciding whether to adjust the laser power density of the second light source accordingly; S6. Determine whether the reflectivity of the white light source meets the standard based on the output value of the spectrometer, and decide whether to adjust the action rate of the first piezoelectric controlled beam splitter accordingly.

[0012] Preferably, it also includes: S7. Clean the surface of the mirror after writing with CO2 to remove the residual particles on the surface.

[0013] The technical effects of the present invention are mainly reflected in the following aspects: 1. "Cold etching" process: using the high photon energy and short pulse characteristics of 266nm deep ultraviolet laser to achieve precise writing of the coating layer and avoid thermal damage; 2. Writing-monitoring integration: Real-time feedback control of the processed surface morphology and optical performance is achieved through beam splitters and white light reflection imaging; 3.Optimization of optical interference: The gradient dielectric film combination forms strong interference reflection in the visible light band, while the deep ultraviolet band penetrates to the absorption layer for writing. Through the two-photon absorption mechanism of the Al2O3 layer, efficient energy coupling of 266nm laser is achieved while avoiding thermal damage to the substrate. 4. Dynamic parameter optimization: Automatically adjust laser power, speed, and scanning path based on online monitoring data to ensure a balance between hydrophobicity and reflectivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the writing device in the embodiment.

[0015] Figure numerals: 1. first light source; 2. second light source; 3. first piezoelectric-controlled beam splitter; 4. first piezoelectric deflection mirror; 5. second beam splitter; 6. photolithography objective; 7. detector; 8. second piezoelectric deflection mirror; 9. third piezoelectric deflection mirror; 10. base; 11. reflector to be engraved. DETAILED DESCRIPTION

[0016] The specific implementation modes of the present invention are further described below in conjunction with the accompanying drawings to make the technical solutions of the present invention easier to understand and grasp. Example

[0017] Reference Figure 1 This embodiment provides a reflector surface hydrophobic micro-nano structure engraving device based on deep ultraviolet laser, including a first light source 1, a second light source 2, a laser scanning module, a second beam splitter 5, a laser stabilization module, a white light imaging module, a lithography objective 6 and a base 10.

[0018] The base 10 adopts a six-axis displacement base, which is used to install the reflector 11 to be engraved. When in use, the position of the reflector 11 to be engraved can be accurately adjusted.

[0019] The first light source 1 is used to provide a white light source, the wavelength range of the white light source is 470nm~670nm, and the power is 5W; the first light source 1 is also configured with a pinhole plate, and the pinhole size is 200um.

[0020] The second light source 2 uses a deep ultraviolet laser to provide a laser source, that is, the laser source is a deep ultraviolet laser. The wavelength of the laser source is 266nm, the pulse width is 10-50ns, the repetition frequency is 1-100kHz, the beam quality is M²<1.3, and the laser power is 10mW-500mW.

[0021] The laser stabilization module is used to maintain the stability of the laser source, and includes a second piezoelectric deflection mirror 8 and a third piezoelectric deflection mirror 9 , which in turn reflect the laser source emitted from the second light source 2 and transmit it to the first piezoelectric deflection mirror 4 .

[0022] The laser scanning module includes a first piezoelectric controlled beam splitter 3 and a first piezoelectric deflection mirror 4. The first piezoelectric deflection mirror 4 is used to transmit the laser source to the first piezoelectric controlled beam splitter 3. The first piezoelectric controlled beam splitter 3 is used to transmit the white light source and the laser source to the second beam splitter 5. The reflectivity of the first piezoelectric controlled beam splitter 3 is >99%, and it transmits 400~700nm white light (transmittance >90%). By precisely controlling the first piezoelectric controlled beam splitter 3 and the first piezoelectric deflection mirror 4, the laser scanning path can be adjusted (X / Y direction scanning accuracy ±0.5μm).

[0023] The second beam splitter 5 is used to transmit the white light source and the laser source to the photolithography objective 6, and to transmit the white light source reflected by the reflector 11 to be engraved to the detector 7; the second beam splitter 5 is used to transmit 95% of the 266nm deep ultraviolet light (zero absorption loss), and transmit 50% of the white light (to the photolithography objective 6) and reflect 50% (to the detector 7).

[0024] The detector 7 includes a CCD camera and a spectrometer, wherein the CCD camera is used to obtain imaging data of the reflected white light source, and the spectrometer is used to detect the reflectivity of the white light source. The photolithography objective 6 is used to focus the white light source and the laser source onto the surface of the reflector 11 to be engraved.

[0025] Since the CCD camera, spectrometer and photolithography objective lens 6 are all relatively mature instruments, their working principles are not described in detail in this embodiment. Among them, the photolithography objective lens 6 is made of ultraviolet fused quartz material, NA = 0.6, working distance 15mm, deep ultraviolet light focusing spot diameter 10~20μm; anti-reflection film (266nm transmittance> 99%, visible light transmittance> 95%).

[0026] The above-mentioned first piezoelectric controlled beam splitter 3, second beam splitter 5, photolithography objective 6 and detector 7 together constitute a white light imaging system, and the specific optical path is: white light → pinhole → first piezoelectric controlled beam splitter 3 (transmission) → second beam splitter 5 (transmission) → photolithography objective 6 → to-be-engraved reflector 11 → reflected light passes through the second beam splitter 5 (reflection) → detector 7 (CCD+spectrometer).

[0027] Through the above scheme, the surface morphology (resolution ≤ 1um) and reflection spectrum (450~650nm) of the processing area can be obtained in real time.

[0028] In this embodiment, the composition and structure of the reflective film to be engraved are shown in the following table.

[0029] Tiers Material Thickness (nm) Core Features 1 <![CDATA[SiO2]]> 150 Visible light high reflectivity substrate matching layer 2 <![CDATA[Al2O3]]> 80 Deep UV absorption layer (bond energy matching) 3 <![CDATA[HfO2]]> 50 Transition layer (to suppress interface stress) 4 <![CDATA[SiO2]]> 20 Surface protection layer (anti-environmental oxidation) Total thickness: 300nm, ensuring that deep ultraviolet light (266nm) penetrates into the Al2O3 layer and is fully absorbed (absorption rate ≥ 85%), while visible light (400-700nm) undergoes interference reflection between SiO2 layers (reflectivity ≥ 95%). Example

[0030] This embodiment is based on the writing device in the above-mentioned embodiment 1, and provides a method for writing a hydrophobic micro-nano structure on the surface of a reflector based on a deep ultraviolet laser. The writing method specifically includes: S1. Use a plasma cleaning machine (Ar gas, power 100W) to treat the coated surface of the reflector 11 to be engraved for T1 time (5 minutes), and then fix it on the six-axis displacement base (vacuum adsorption, flatness error <0.1um).

[0031] S2. Positioning an initial processing area on the reflector 11 to be engraved by using the first light source 1.

[0032] S3. Adjust each piezoelectric deflecting mirror so that the spot of the laser source coincides with the initial processing area (deviation < 2um).

[0033] The adjustment parameters of the above steps refer to the following table: parameter Setting example Laser power density 0.5~1.2J / cm² Scan speed 300~800mm / s Pulse repetition frequency 20~50kHz White light imaging frame rate 100fps (real-time feedback) S4, controlling the first piezoelectric controlled beam splitter 3, the first piezoelectric deflection mirror 4 and the photolithography objective lens 6 to operate so as to control the laser source to write honeycomb-shaped pits on the coating surface.

[0034] In this step, the diameter of the honeycomb pits is 200-500 nm and the depth is 50-150 nm.

[0035] S5. Determine the uniformity of the honeycomb pits based on the imaging data output by the CCD camera, and decide whether to adjust the laser power density of the second light source 2 accordingly.

[0036] In this step, if structural inhomogeneity is detected (e.g., pit depth difference > 20%), the laser power density is automatically adjusted.

[0037] S6. Determine whether the reflectivity of the white light source meets the standard based on the output value of the spectrometer, and decide whether to adjust the action rate of the first piezoelectric controlled beam splitter 3 accordingly.

[0038] In this step, if the reflectivity of a certain band (such as 550nm) decreases by >5%, the trigger scanning speed is increased (reducing single-point energy accumulation).

[0039] S7. Use CO2 (pressure 10MPa, temperature 40°C) to clean the surface of the engraved mirror to remove residual particles on the surface.

[0040] S8. Test the contact angle (water drop 4μL), reflectivity (450~650nm integral value) and weather resistance (storage for 1000 hours in 85℃ / 85%RH environment) of the reflector surface.

[0041] In addition, this embodiment also provides examples for writing tests on automobile rearview mirrors and traffic monitoring reflectors, as follows: Super hydrophobic writing on car rearview mirror: Coating parameters: SiO2(150nm) / Al2O3(80nm) / HfO2(50nm) / SiO2(20nm).

[0042] Device parameters: laser power density 0.9J / cm², scanning speed 500mm / s, hexagonal close-packed path; white light imaging frame rate 120fps, spectral monitoring band 500~600nm.

[0043] Writing effect: After deep ultraviolet laser (0.9J / cm², 500mm / s) writing, uniform honeycomb pits (diameter 400nm, depth 120nm) were formed on the surface; the visible light reflectivity was 92.1% (originally 95.4%), the contact angle was 154°, and the raindrop sliding time was <1.5 seconds; during the processing, it was detected that the local reflectivity dropped by 4.8%, and the system automatically increased the scanning speed to 550mm / s, and the reflectivity recovered to 91.2%.

[0044] Traffic monitoring reflector anti-fouling writing: Coating type: Ag / SiO2 composite film (Ag layer thickness 100nm, SiO2 protective layer 50nm).

[0045] Device parameters: Laser power density 0.6 J / cm², scanning speed 700 mm / s, parallel line scanning (pitch 5 μm); white light imaging detected stripe-like inhomogeneities, and the system switched to a spiral scanning path.

[0046] result: Contact angle 149°±3°, reflectivity 88.7% (originally 92.5%); after 2000 hours of salt spray test, the contact angle remained at 145°, and the reflectivity loss was <3%.

[0047] Efficacy: Imaging resolution is improved to 0.5μm, but additional filters are required to isolate deep ultraviolet stray light.

[0048] Of course, the above are only typical examples of the present invention. In addition, the present invention may also have many other specific implementations. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the present invention.

Claims

1. A device for writing hydrophobic micro-nanostructure on the surface of a reflector based on deep ultraviolet laser, characterized in that: include: A first light source (1), used to provide a white light source; A second light source (2) is used to provide a laser source, wherein the laser source is a deep ultraviolet laser; The laser scanning module comprises a first piezoelectric controlled beam splitter (3) and a first piezoelectric deflection mirror (4); wherein the first piezoelectric deflection mirror (4) is used to transmit a laser source to the first piezoelectric controlled beam splitter (3); and the first piezoelectric controlled beam splitter (3) is used to transmit a white light source and a laser source to a second beam splitter (5); A second beam splitter (5) is used to transmit the white light source and the laser source to the photolithography objective (6), and transmit the white light source reflected by the reflector (11) to be engraved to the detector (7); A detector (7) is used to obtain the white light source reflected by the reflector (11) to be engraved from the second beam splitter (5) and detect its imaging data and reflectivity accordingly; A photolithography objective lens (6), used for focusing a white light source and a laser source onto a surface of a reflector (11) to be engraved; and a base (10) for carrying a reflector (11) to be engraved.

2. The device for writing hydrophobic micro-nanostructure on the surface of a reflector based on deep ultraviolet laser as claimed in claim 1, characterized in that: It also includes a laser stabilization module, which includes a second piezoelectric deflection mirror (8) and a second piezoelectric deflection mirror (8); the second piezoelectric deflection mirror (8) and the second piezoelectric deflection mirror (8) are used to sequentially transmit the laser source emitted from the second light source (2) to the first piezoelectric deflection mirror (4).

3. The device for writing hydrophobic micro-nanostructure on the surface of a reflector based on deep ultraviolet laser as claimed in claim 2, characterized in that: A pinhole plate is also arranged between the first piezoelectric controlled beam splitter (3) and the white light source.

4. The device for writing hydrophobic micro-nanostructure on the surface of a reflector based on deep ultraviolet laser as claimed in claim 3, characterized in that: The detector (7) comprises a CCD camera and a spectrometer.

5. The device for writing hydrophobic micro-nanostructure on the surface of a reflector based on deep ultraviolet laser as claimed in claim 4, characterized in that: The base (10) adopts a six-axis displacement base.

6. A method for writing hydrophobic micro-nano structures on the surface of a reflector based on deep ultraviolet laser, implemented based on the writing device according to claim 5, characterized in that: include: S1, using a plasma cleaning machine to treat the coated surface of the reflector (11) to be engraved for a period of T1, and then fixing it on a six-axis displacement base; S2, positioning an initial processing area on the reflective mirror (11) to be engraved using a first light source (1); S3, adjusting each piezoelectric deflection mirror so that the spot of the laser source coincides with the initial processing area; S4, controlling the first piezoelectric controlled beam splitter (3), the first piezoelectric deflection mirror (4) and the photolithography objective lens (6) to operate so as to control the laser source to write honeycomb-shaped pits on the coating surface; S5, judging the uniformity of the honeycomb-shaped pits based on the imaging data output by the CCD camera, and deciding whether to adjust the laser power density of the second light source (2) accordingly; S6. Based on the output value of the spectrometer, determine whether the reflectivity of the white light source meets the standard, and decide whether to adjust the action rate of the laser scanning module accordingly.

7. A method for writing hydrophobic micro-nanostructures on the surface of a reflector based on deep ultraviolet laser as claimed in claim 6, characterized in that: include: S7. Clean the surface of the mirror after writing with CO2 to remove the residual particles on the surface.

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