Preparation method of visible light three-way optical filter

Abstract

The preparation method of the visible light three-way optical filter comprises the following steps: S1, cleaning the surface of the glass substrate; s2, a tool clamp is put in, and the tool clamp is hung in a cavity of the vacuum coating machine; s3, starting the vacuum coating machine to vacuumize, and cleaning by a radio frequency ion source; s4, plating a short-wave-pass film system on the first surface, namely Sub / 15.97 H, 523.84 L, 22.95 H, 196.86 L, 179.93 H, 276.73 L, 74.08 H, 193.67 L, 105.63 H, 388.35 L, 40H, 202.4 L, 78.48 H, 29.96 H, 475.84 L, 92.95 H, 106.08 L, 62.04 H, 42.3 L, 99.94 H, 76.94 L, 179.5 H, 145.53 L, 81.08 H, 90.84 L, 194.09 H, 65.85 L, 132.28 H, 230.3 L / Air, Sub is a glass substrate, Air is air, H is a TiO2 film layer, and L is a titanium dioxide film layer. S5, after the short-wave-pass film system is completed, the cavity is cooled and taken out; s6, repeating the steps S1 to S3; s7, plating an antireflection film system on the second surface, wherein the antireflection film system is Sub / 12.84 H, 36.22 L, 54.58 H, 8L, 45H and 91.86 L / Air; and S8, cooling the cavity and taking out.

Description

Technical Field

[0001] This disclosure relates to the field of optical coating, and more specifically to a method for preparing a visible light three-way filter. Background Technology

[0002] Visible light three-way filters, with their ability to transmit three different wavelengths of light simultaneously, have wide applications in various fields. In machine vision applications such as 3D inspection and optical instruments, it is necessary to filter specific wavelengths of light to improve image contrast and clarity, helping machines to more accurately identify objects and features. Visible light three-way filters allow specific wavelengths of visible light to pass through while blocking other wavelengths, thus meeting the specific wavelength requirements of machine vision systems. Visible light three-way filters also play an important role in other fields such as aerial surveying and plant health monitoring. For example, in aerial surveying, they can help provide more affordable and lightweight alternatives; in plant health monitoring, they can be used to collect blue-green-near-infrared extended normalized difference vegetation index (ENDVI) data, providing more accurate information about plant or crop health. Therefore, for the specific three wavelengths (i.e., the transmission bands), higher transmittance is better, while for other wavelengths (i.e., the cutoff bands), lower transmittance is better. Thus, continuous development is needed to improve transmittance. Summary of the Invention

[0003] In view of the problems existing in the background art, one object of this disclosure is to provide a method for preparing a visible light three-way filter, wherein the glass substrate prepared therefrom, together with the short-wavelength pass film system on the first side and the anti-reflection film system on the second side, has an average transmittance of more than 99% in each wavelength band of 450-470nm, 520-530nm, and 630-655nm at a 0° test angle, and an average transmittance of less than 0.7% in each wavelength band of the cutoff range of 490-500nm and 550-600nm.

[0004] Therefore, a method for preparing a visible light three-way filter includes the following steps: S1, cleaning the surface of a glass substrate; S2, placing the treated glass substrate into a fixture, and hanging the fixture with the glass substrate inside the vacuum coating machine cavity, setting the cavity temperature to 180℃; S3, starting the vacuum coating machine to evacuate the vacuum, achieving a vacuum level of 1.0 × 10⁻⁶. -3Pa, turn on the radio frequency ion source for auxiliary coating of the vacuum coating machine for cleaning. The cleaning time is 6 minutes. The parameters of the radio frequency ion source are: ion acceleration voltage 850V, ion current 800mA, grid ion deflection voltage 600V, argon flow rate 8sccm, oxygen flow rate 75sccm; S4, deposit a short-wavelength film system on the first surface of the glass substrate. The short-wavelength film system is: Sub / 15.97H 523.84L 22.95H 196.86L 179.93H 276.73L 74.08H 193.67L 105.63H 388.35L 40H 202.4L 78.48H 293.92L 53.36H 81.09L 66.2H 475.8L 92.95H 106.08L 72.93H 86.84L64.04H42.3L 99.94H 76.94L 179.5H 145.53L 81.08H 90.84L 194.09H65.85L 68.13H301.65L 85.91H 158.16L 132.28H 230.3L / Air, where Sub is the glass substrate, Air is air, H represents a TiO2 film with an optical thickness of λ0 / 4, L represents a SiO2 film with an optical thickness of λ0 / 4, λ0 is the incident light wavelength, and the numbers before H and L represent the thickness of the film in nm. Both the TiO2 and SiO2 films are deposited using electron beam evaporation with radio frequency ion source assisted evaporation. The deposition rate of the TiO2 film is 0.3 nm / s, and the deposition rate of the SiO2 film is 1.0 nm / s. S5, After the short-wavelength pass film system is deposited on the first side of the glass substrate, wait for the cavity to cool to below 50-60℃, and then remove the tooling fixture along with the glass substrate with the first side deposited. S6, Repeat steps S1 to S3. S7, Deposit an antireflection film system on the second side of the glass substrate. The antireflection film system is Sub / 12.84H 36.22L 54.58H 8L 45H. 91.86L / Air, where Sub is the glass substrate, Air is air, H represents a TiO2 film with an optical thickness of λ0 / 4, L represents a SiO2 film with an optical thickness of λ0 / 4, λ0 is the incident light wavelength, and the numbers before H and L are the thickness of the film in nm. Both the TiO2 and SiO2 films are deposited using electron beam evaporation with radio frequency ion source assisted evaporation. The deposition rate of the TiO2 film is 0.3 nm / s, and the deposition rate of the SiO2 film is 1.0 nm / s. S8, After the antireflection coating system is deposited on the second side of the glass substrate, wait for the cavity to cool to below 50-60℃ and then remove the tooling fixture along with the glass substrate.

[0005] The beneficial effects of this disclosure are as follows: In the method for preparing the visible light three-way filter according to this disclosure, by step S4 of depositing a short-wavelength pass film system consisting of 38 layers of TiO2 and SiO2 on the first surface of the glass substrate and step S7 of depositing an anti-reflection film system consisting of 6 layers of TiO2 and SiO2 on the second surface of the glass substrate, combined with the surface cleaning of steps S1 and S6, the cavity temperature of steps S2 and S6, the radio frequency ion source cleaning of steps S3 and S6, and the cooling of steps S5 and S8, as verified by the test process, the average transmittance of the glass substrate together with the short-wavelength pass film system on the first surface and the anti-reflection film system on the second surface at a 0° test angle in each band of 450-470nm, 520-530nm, and 630-655nm is above 99%, and the average transmittance in each band of the cutoff range of 490-500nm and 550-600nm is less than 0.7%. Attached Figure Description

[0006] Figure 1 This is a schematic structural diagram of a glass substrate and the film system on both sides prepared according to the method for preparing a visible light three-way filter disclosed herein.

[0007] Figure 2 This is a graph showing the transmittance of the glass substrate and the film system on both sides of Example 1 at a test angle of 0°. Detailed Implementation

[0008] It will be understood that the disclosed embodiments are merely examples of this disclosure, which can be implemented in various forms. Therefore, the specific details disclosed herein should not be construed as limiting, but are intended only as the basis for the claims and as an illustrative basis to teach those skilled in the art how to implement this disclosure in various ways.

[0009] [Preparation method of visible light three-way filter]

[0010] Reference Figure 1 The method for preparing the visible light three-way filter according to this disclosure includes the following steps:

[0011] S1, Clean the surface of the glass substrate;

[0012] S2, Place the processed glass substrate into the tooling fixture, and hang the tooling fixture with the glass substrate into the vacuum coating machine cavity. Set the temperature of the cavity to 180℃.

[0013] S3, the vacuum coating machine starts vacuuming, and the vacuum level reaches 1.0×10⁻⁶. -3Pa, turn on the radio frequency ion source of the auxiliary coating of the vacuum coating machine for cleaning. The cleaning time is 6 minutes. The parameters of the radio frequency ion source are: ion acceleration voltage 850V, ion current 800mA, grid ion deflection voltage 600V, argon flow rate 8sccm, oxygen flow rate 75sccm.

[0014] S4. A short-pass film system is deposited on the first surface of the glass substrate. The short-pass film system is as follows: Sub / 15.97H 523.84L 22.95H 196.86L 179.93H 276.73L 74.08H 193.67L 105.63H 388.35L 40H 202.4L 78.48H 293.92L 53.36H 81.09L 66.2H 475.8L 92.95H 106.08L 72.93H 86.84L 64.04H 42.3L 99.94H 76.94L 179.5H 145.53L 81.08H 90.84L 194.09H 65.85L 68.13H 301.65L 85.91H 158.16L 132.28H 230.3L / Air, where Sub is the glass substrate, Air is air, H represents a TiO2 film with an optical thickness of λ0 / 4, L represents a SiO2 film with an optical thickness of λ0 / 4, λ0 is the incident light wavelength, and the numbers before H and L are the thickness of the film in nm. Both TiO2 and SiO2 films are deposited using electron beam evaporation with radio frequency ion source assisted evaporation. The deposition rate of the TiO2 film is 0.3 nm / s, and the deposition rate of the SiO2 film is 1.0 nm / s.

[0015] S5. After the short-wavelength film system is deposited on the first side of the glass substrate, wait for the cavity to cool down to below 50-60°C and then take out the tooling fixture along with the glass substrate whose first side has been deposited.

[0016] S6, repeat steps S1 to S3;

[0017] S7. An antireflection coating system is deposited on the second surface of the glass substrate. The antireflection coating system is Sub / 12.84H 36.22L54.58H8L 45H 91.86L / Air, where Sub is the glass substrate, Air is air, H represents a TiO2 film layer with an optical thickness of λ0 / 4, L represents a SiO2 film layer with an optical thickness of λ0 / 4, λ0 is the incident light wavelength, and the numbers before H and L are the thickness of the film layer in nm. Both the TiO2 film layer and the SiO2 film layer are deposited using electron beam evaporation and assisted by radio frequency ion source. The deposition rate of the TiO2 film layer is 0.3 nm / s, and the deposition rate of the SiO2 film layer is 1.0 nm / s.

[0018] S8. After the antireflective coating system is deposited on the second side of the glass substrate, wait for the cavity to cool down to below 50-60℃ and then remove the tooling fixture along with the glass substrate.

[0019] In the method for preparing a visible light three-way filter according to this disclosure, by step S4 of depositing a short-wavelength pass film system consisting of 38 layers of TiO2 and SiO2 on the first surface of the glass substrate and step S7 of depositing an anti-reflection film system consisting of 6 layers of TiO2 and SiO2 on the second surface of the glass substrate, combined with the surface cleaning of steps S1 and S6, the cavity temperature of steps S2 and S6, the radio frequency ion source cleaning of steps S3 and S6, and the cooling of steps S5 and S8, as verified by the test process, the average transmittance of the glass substrate together with the short-wavelength pass film system on the first surface and the anti-reflection film system on the second surface at a test angle of 0° is above 99% in each wavelength band of 450-470nm, 520-530nm, and 630-655nm, and the average transmittance in each wavelength band of the cutoff range of 490-500nm and 550-600nm is less than 0.7%.

[0020] The surface cleaning in steps S1 and S6 helps improve the surface condition of the first and second surfaces of the glass substrate, and contributes to enhancing the adhesion between the short-pass coating system on the first surface and the antireflective coating system on the second surface and their corresponding surfaces on the glass substrate. For example, the glass substrate surface can be cleaned using ultrasound or by hand. Further, in step S1, the ultrasonic surface cleaning of the glass substrate involves polishing with an alumina polishing slurry followed by ultrasonic rinsing with pure water. For example, the alumina polishing slurry used is a 0.1μm polycrystalline diamond slurry from Nanjing Hengrui Precision Optics Co., Ltd.

[0021] In one example, in step S1, the glass substrate is K9 glass.

[0022] The temperature setting in step S2 heats the glass substrate through the cavity of the coating machine, which helps the film grow from the glass substrate and reduces the stress during film growth. The vacuum coating machine for step S2 is, for example, the OTFC-1300 vacuum coating machine with an RF ion source from Lightspeed Technology (Shanghai) Co., Ltd.

[0023] Step S3 uses a radio frequency ion source for cleaning, which removes impurities and oil molecules adsorbed on the surface of the glass substrate, thereby significantly improving the interface state and helping to improve the bonding performance between the film and the glass substrate. At the same time, cleaning with a radio frequency ion source can heat the surface of the glass substrate, which helps the film grow from the glass substrate and reduces the film growth stress.

[0024] In one example, in steps S4 and S7, the parameters of the radio frequency ion source used for depositing the TiO2 film are: ion acceleration voltage 1200V, ion current 900mA, grid ion deflection voltage 650V, argon flow rate 8sccm, and oxygen flow rate 50sccm; the parameters of the radio frequency ion source used for depositing the SiO2 film are: ion acceleration voltage 850V, ion current 850mA, grid ion deflection voltage 650V, argon flow rate 8sccm, and oxygen flow rate 50sccm.

[0025] In steps S4 and S7, for example, the thickness of the film layer is monitored by using the crystal oscillator method with the corresponding crystal oscillators of multiple crystal oscillators of the crystal controller. After cleaning with the radio frequency ion source, the crystal controller controls the new crystal oscillator among the multiple crystal oscillators to work accordingly, and the crystal oscillator frequency is not less than 5.99MHz.

[0026] In one example, after step S8, the glass substrate, together with the short-pass film system on the first side and the antireflection film system on the second side, exhibits an average transmittance of over 99% in each wavelength band at a 0° test angle in the 450-470nm, 520-530nm, and 630-655nm bands, and an average transmittance of less than 0.7% in each wavelength band in the cutoff range of 490-500nm and 550-600nm.

[0027] [test]

[0028] Example 1

[0029] Example 1 uses the following steps:

[0030] S1. The surface of the glass substrate is cleaned. The glass substrate is K9 glass. The surface of the glass substrate is cleaned by ultrasonic cleaning. The ultrasonic cleaning of the glass substrate involves polishing with alumina polishing fluid and then ultrasonic cleaning with pure water. The alumina polishing fluid is 0.1μm polycrystalline diamond fluid from Nanjing Hengrui Precision Optics Co., Ltd.

[0031] S2, Place the processed glass substrate into the tooling fixture, and hang the tooling fixture with the glass substrate into the vacuum coating machine cavity. The temperature of the cavity is set to 180℃. The vacuum coating machine is the OTFC-1300 vacuum coating machine with radio frequency ion source from Guangchi Technology (Shanghai) Co., Ltd.

[0032] S3, the vacuum coating machine starts vacuuming, and the vacuum level reaches 1.0×10⁻⁶. -3 Pa, turn on the radio frequency ion source of the auxiliary coating of the vacuum coating machine for cleaning. The cleaning time is 6 minutes. The parameters of the radio frequency ion source are: ion acceleration voltage 850V, ion current 800mA, grid ion deflection voltage 600V, argon flow rate 8sccm, oxygen flow rate 75sccm.

[0033] S4. A short-pass film system is deposited on the first surface of the glass substrate. The short-pass film system is as follows: Sub / 15.97H 523.84L 22.95H 196.86L 179.93H 276.73L 74.08H 193.67L 105.63H 388.35L 40H 202.4L 78.48H 293.92L 53.36H 81.09L 66.2H 475.8L 92.95H 106.08L 72.93H 86.84L 64.04H 42.3L 99.94H 76.94L 179.5H 145.53L 81.08H 90.84L 194.09H 65.85L 68.13H 301.65L 85.91H 158.16L 132.28H 230.3L / Air, where Sub is the glass substrate, Air is air, H represents a TiO2 film with an optical thickness of λ0 / 4, L represents a SiO2 film with an optical thickness of λ0 / 4, λ0 is the incident light wavelength, and the numbers before H and L are the thickness of the film in nm. Both TiO2 and SiO2 films are deposited using electron beam evaporation with radio frequency ion source assisted evaporation. The deposition rate of the TiO2 film is 0.3 nm / s, and the deposition rate of the SiO2 film is 1.0 nm / s.

[0034] S5. After the short wavepass film system is deposited on the first side of the glass substrate, wait for the cavity to cool to 55°C and then take out the tooling fixture along with the glass substrate whose first side has been deposited.

[0035] S6, repeat steps S1 to S3;

[0036] S7. An antireflection coating system is deposited on the second surface of the glass substrate. The antireflection coating system is Sub / 12.84H 36.22L54.58H8L 45H 91.86L / Air, where Sub is the glass substrate, Air is air, H represents a TiO2 film layer with an optical thickness of λ0 / 4, L represents a SiO2 film layer with an optical thickness of λ0 / 4, λ0 is the incident light wavelength, and the numbers before H and L are the thickness of the film layer in nm. Both the TiO2 film layer and the SiO2 film layer are deposited using electron beam evaporation and assisted by radio frequency ion source. The deposition rate of the TiO2 film layer is 0.3 nm / s, and the deposition rate of the SiO2 film layer is 1.0 nm / s.

[0037] S8. After the anti-reflection coating system is deposited on the second side of the glass substrate, wait for the cavity to cool to 55°C and then remove the tooling fixture along with the glass substrate.

[0038] In steps S4 and S7,

[0039] The parameters of the radio frequency ion source used to deposit the TiO2 film are: 1200V ion acceleration voltage, 900mA ion current, 650V grid ion deflection voltage, 8sccm argon flow rate, and 50sccm oxygen flow rate.

[0040] The parameters of the radio frequency ion source used when depositing the SiO2 film are: 850V ion acceleration voltage, 850mA ion current, 650V grid ion deflection voltage, 8sccm argon flow rate, and 50sccm oxygen flow rate.

[0041] The thickness of the film layer is monitored by using the corresponding crystal oscillators of multiple crystal oscillators in the crystal controller. After cleaning with radio frequency ion source, the crystal controller controls the new crystal oscillator in the multiple crystal oscillators to work accordingly. The crystal oscillator frequency is not less than 5.99MHz.

[0042] Figure 2 This is a graph showing the transmittance of the glass substrate and the film systems on both sides of Example 1 at a test angle of 0°. From... Figure 2 It can be seen that the average transmittance of the glass substrate, together with the short-pass film system on the first side and the antireflection film system on the second side, at a test angle of 0° in the wavelength bands of 450-470nm, 520-530nm, and 630-655nm are 99.94%, 99.99%, and 99.91% respectively (i.e., all above 99%). The average transmittance in the cutoff ranges of 490-500nm and 550-600nm is 0.56% and 0.22% respectively (i.e., both less than 0.7%).

[0043] In addition, the overall performance of the glass substrate, together with the short-pass film system on the first surface and the antireflection film system on the second surface, was tested as follows.

[0044] Water immersion test: The glass substrate prepared in Example 1, together with the short-wavelength membrane system on the first side and the anti-reflection membrane system on the second side, was subjected to a water immersion test with tap water for 10 minutes. No short-wavelength membrane system on the first side and the anti-reflection membrane system on the second side were found to detach from the glass substrate, nor were any cracks found in the short-wavelength membrane system on the first side and the anti-reflection membrane system on the second side.

[0045] Adhesion test: When 3M tape was applied to the short-pass film system on the first side of the glass substrate by hand and the tape was pulled in the opposite direction to the adhesive end, the short-pass film system was not pulled up. For the second side of the glass substrate, when 3M tape was applied to the antireflection film system on the second side of the glass substrate by hand and the tape was pulled in the opposite direction to the adhesive end, the antireflection film system was not pulled up.

[0046] The water immersion test and adhesion test showed that the short-pass film system on the first side and the antireflection film system on the second side of the glass substrate had good adhesion.

[0047] Several exemplary embodiments have been described in detail above, but this document is not intended to limit itself to the explicitly disclosed combinations. Therefore, unless otherwise stated, the various features disclosed herein can be combined to form several other combinations, which are not shown for simplicity.

Claims

1. A method of making a visible light triple-tap filter, characterized by, The method comprises the steps of: S1, cleaning the surface of the glass substrate; S2, placing the treated glass substrate into a fixture, and hanging the fixture with the glass substrate into a cavity of a vacuum coating machine, and setting the temperature of the cavity to 180℃; S3, the vacuum coater starts to pump, the vacuum degree reaches 1.0x10 -3 Pa, the auxiliary coating RF ion source of the vacuum coater is opened for cleaning, the cleaning time is 6 min, and the parameters of the RF ion source are as follows: exit ion acceleration voltage 850 V, exit ion current 800 mA, mesh ion deflection voltage 600 V, argon flow rate 8 sccm, and oxygen flow rate 75 sccm; S4, coating a short-wave transmission film system on the first surface of the glass substrate, wherein the short-wave transmission film system is Sub / 15.97H523.84L 22.95H196.86L 179.93H 276.73L 74.08H 193.67L105.63H 388.35L 40H 202.4L 78.48H293.92L 53.36H 81.09L66.2H 475.8L 92.95H 106.08L 72.93H 86.84L 64.04H42.3L99.94H 76.94L 179.5H 145.53L 81.08H 90.84L 194.09H 65.85L68.13H 301.65L85.91H 158.16L 132.28H 230.3L / Air, wherein Sub is the glass substrate, Air is air, H represents a TiO2 film layer with a λ0 / 4 optical thickness, L represents a SiO2 film layer with a λ0 / 4 optical thickness, λ0 is the wavelength of incident light, the numbers before H and L are the thicknesses of the film layers in nm, the TiO2 film layer and the SiO2 film layer are both prepared by electron beam evaporation and radio frequency ion source assisted evaporation, the deposition rate of the TiO2 film layer is 0.3 nm / s, and the deposition rate of the SiO2 film layer is 1.0 nm / s; S5, after the coating of the short-wave transmission film system on the first surface of the glass substrate is completed, the fixture and the glass substrate with the first surface coated are taken out when the cavity is cooled to below 50-60℃; S6, repeating steps S1 to S3; S7, coating an anti-reflection film system on the second surface of the glass substrate, wherein the anti-reflection film system is Sub / 12.84H 36.22L54.58H 8L45H 91.86L / Air, wherein Sub is the glass substrate, Air is air, H represents a TiO2 film layer with a λ0 / 4 optical thickness, L represents a SiO2 film layer with a λ0 / 4 optical thickness, λ0 is the wavelength of incident light, the numbers before H and L are the thicknesses of the film layers in nm, the TiO2 film layer and the SiO2 film layer are both prepared by electron beam evaporation and radio frequency ion source assisted evaporation, the deposition rate of the TiO2 film layer is 0.3 nm / s, and the deposition rate of the SiO2 film layer is 1.0 nm / s; S8, after the coating of the anti-reflection film system on the second surface of the glass substrate is completed, the fixture and the glass substrate are taken out when the cavity is cooled to below 50-60℃.

2. The method according to claim 1, wherein in step S1, the surface of the glass substrate is cleaned by ultrasonic cleaning or manual wiping.

3. The method according to claim 2, wherein in step S1, the surface of the glass substrate is cleaned by manual wiping. ​ In step S1, the surface cleaning treatment of the glass substrate by ultrasonic wave is polishing by alumina polishing liquid, and then ultrasonic water cleaning; The alumina polishing liquid is polycrystalline diamond liquid of 0.1 μm type.

4. The preparation method of the visible light three-way filter according to claim 1, characterized in that, In step S1, the glass substrate is K9 glass.

5. The preparation method of the visible light three-way filter according to claim 1, characterized in that, In step S2, the vacuum coating machine is OTFC-1300 of light chase machine.

6. The preparation method of the visible light three-way filter according to claim 1, characterized in that, In step S4 and step S7, The parameters of the radio frequency ion source used for plating the TiO2 film layer are: exit ion acceleration voltage 1200V, exit ion current 900mA, grid ion deflection voltage 650V, argon flow rate 8sccm, oxygen flow rate 50sccm; The parameters of the radio frequency ion source used for plating the SiO2 film layer are: exit ion acceleration voltage 850V, exit ion current 850mA, grid ion deflection voltage 650V, argon flow rate 8sccm, oxygen flow rate 50sccm.

7. The preparation method of the visible light three-way filter according to claim 1, characterized in that, In step S4 and step S7, the thickness of the film layer is monitored by using the crystal oscillator method with the corresponding crystal oscillator pieces of the crystal controller, the new crystal oscillator piece in the plurality of crystal oscillator pieces is controlled to work after the radio frequency ion source is cleaned, and the crystal oscillator frequency is not less than 5.99MHz.

8. The preparation method of the visible light three-way filter according to claim 1, characterized in that, After step S8 is completed, the transmittance of the glass substrate together with the short wave passing film system of the first surface and the anti-reflection film system of the second surface at 0° test angle in each waveband of 450-470nm, 520-530nm and 630-655nm is more than 99% on average, and the transmittance in each waveband of 490-500nm and 550-600nm is less than 0.7% on average.

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