A receiving end filter and a preparation method and a combined filter

Abstract

The application provides a receiving end filter and a preparation method thereof, and a combined filter, and belongs to the field of coating technology. The application solves the problem that the existing receiving end filter is relatively single. The receiving end filter comprises a glass substrate, a narrow-band pass film system and an anti-reflection film system. The narrow-band pass film system comprises silicon oxide film layers and hydrogenated silicon / hydroxylated silicon / nitrogen hydrogenated silicon film layers which are alternately deposited layer by layer, and a silicon oxide film layer as an outermost layer. The anti-reflection film system comprises silicon oxide film layers and hydrogenated silicon / hydroxylated silicon / nitrogen hydrogenated silicon film layers which are alternately deposited layer by layer, and a silicon oxide film layer as an outermost layer. The receiving end filter has the advantages that the overlapping high transmittance is achieved within an angle range of 0°-60° of an incident angle, and the demand cut-off spectrum band has the effect of inhibiting the transmission of light signals within the angle range of 0°-60° of the incident angle.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, and relates to a receiving end filter and its preparation method, as well as a combined filter. Background Technology

[0002] As people's demands for mobile phones and other electronic products become increasingly diverse and demanding, existing camera receiver filters for these products suffer from the following problems: When the high transmittance band of the receiver filter is in the wavelength range of 1100nm-1800nm, 1. within an incident angle range of 0°-60°, the transmittance is low in the overlapping high transmittance spectrum; 2. within the incident angle range of 0°-60°, the filter cannot suppress the passage of light signals in the required cutoff spectrum. Therefore, it cannot meet people's higher usage requirements for electronic products, such as achieving high transmittance in a wide-angle transmission band to enable imaging and object recognition functions.

[0003] Prior invention application CN201910165758.3 discloses an optical filter and its preparation method, specifically disclosing that the filter includes a transparent substrate and a first long-pass film system and a second long-pass film system respectively disposed on both sides of the transparent substrate; both the first and second long-pass film systems include alternating high-refractive-index film layers and low-refractive-index film layers. This invention only yields a near-infrared filter that transmits light in the 830-950nm range, and it is a single filter. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned technical problems by proposing a receiver filter and its preparation method. The receiver filter can achieve high transmittance in the wavelength range of 1100nm-1800nm ​​and in the angle range of 0°-60°, with overlapping high transmittance. In the angle range of 0°-60°, the required cutoff band has the function of suppressing the passage of light signals.

[0005] The objective of this invention can be achieved through the following technical solution: a receiving end filter, comprising a glass substrate, a narrow bandpass film system disposed on one side of the glass substrate, and an antireflection film system disposed on the other side of the glass substrate, wherein the narrow bandpass film system comprises alternating layers of silicon oxide film and silicon hydride / silicon hydroxide / silicon nitride film, and a silicon oxide film layer as the outermost layer, and the antireflection film system comprises alternating layers of silicon oxide film and silicon hydride / silicon hydroxide / silicon nitride film, with a silicon oxide film layer as the outermost layer.

[0006] In the aforementioned receiver filter, the silicon hydride / silicon hydroxide / silicon hydride nitrogen film is a high refractive index film, and the silicon oxide film is a low refractive index film.

[0007] In the aforementioned receiver filter, the narrow bandpass film system has the structure (LH)^nL, where the H layer is a silicon hydride / silicon hydroxide / silicon hydride layer, L is a silicon oxide layer, and n is the number of basic film stacks (HL).

[0008] In the aforementioned receiver filter, the structure of the antireflective film system is (LH)^nL, where the H layer is a silicon hydride / silicon hydroxide / silicon hydride layer, L is a silicon oxide layer, and n is the number of cycles in the basic film stack (HL).

[0009] In one of the aforementioned receiver filters, the thickness of the glass substrate is ≤3mm.

[0010] A method for preparing a receiver filter, characterized by comprising the following steps:

[0011] Step S01: Place the glass substrate into the low vacuum chamber and evacuate it;

[0012] Step S02: Place the glass substrate into the high vacuum chamber and evacuate it;

[0013] Step S03: The surface of the glass substrate is bombarded with plasma emitted from a radio frequency source;

[0014] Step S04: A narrow bandpass film system is deposited on one side of a glass substrate using a magnetron sputtering method. The narrow bandpass film system includes alternating layers of silicon oxide film and silicon hydride / silicon hydroxide / silicon hydride film, as well as an outermost silicon oxide film.

[0015] Step S05: An antireflection film system is deposited on the other side of the glass substrate using a magnetron sputtering method. The antireflection film system includes alternating layers of silicon oxide film and silicon hydride / silicon hydroxide / silicon hydride film, as well as an outermost silicon oxide film.

[0016] Step S06: Allow the glass substrate to cool naturally to room temperature to obtain the receiver filter.

[0017] In the above-described method for preparing the receiver filter, step S04 specifically includes:

[0018] Step S041: Deposit silicon oxide film. The second radio frequency oxidation source is activated. The working gas Ar flow rate is 50-500 sccm, the O2 flow rate is 100-500 sccm, the sputtering source power is 5 kW-12 kW, the oxidation source power is 2 kW-4 kW, and the film deposition rate is 0.2-1.2 nm / s.

[0019] Step S042: Deposition of silicon hydride / silicon hydroxide / silicon hydride nitrogen film is performed. The first radio frequency oxidation source is activated, with working gas flow rates of Ar (50-500 sccm), H2 (10-100 sccm), O2 (0-50 sccm), and N2 (0-50 sccm). The sputtering source power is 5 kW-12 kW, the oxidation source power is 1 kW-4 kW, and the film deposition rate is 0.2-0.7 nm / s.

[0020] Step S043, repeat steps S101-S102 in this manner until the last second layer;

[0021] Step S044: The last layer is a silicon oxide film deposited according to step S041.

[0022] In the above-described method for preparing the receiver filter, step S05 specifically includes:

[0023] Step S051: Deposit silicon oxide film. The second radio frequency oxidation source is activated. The working gas Ar flow rate is 50-500 sccm, the O2 flow rate is 100-500 sccm, the sputtering source power is 5 kW-12 kW, the oxidation source power is 2 kW-4 kW, and the film deposition rate is 0.2-1.2 nm / s.

[0024] Step S052: Deposition of silicon hydride / silicon hydroxide / silicon hydride nitrogen film is performed. The first radio frequency oxidation source is activated. The working gas flow rate is 50-500 sccm, H2 flow rate is 10-100 sccm, O2 flow rate is 0-50 sccm, N2 flow rate is 0-50 sccm, sputtering source power is 5 kW-12 kW, oxidation source power is 1 kW-4 kW, and film deposition rate is 0.2-0.7 nm / s.

[0025] Step S053, repeat steps S051-S052 in this manner until the last second layer;

[0026] Step S054: The last layer is a silicon oxide film deposited according to step S051.

[0027] In the above-described method for preparing a receiver filter, the prepared receiver filter has an incident angle range of 0°-60° and high transmittance with overlap; it has the function of suppressing the passage of light signals in wavelength bands where high transmittance is not required; the high transmittance band of the receiver filter is in the wavelength range of 1100nm-1800nm.

[0028] A combined filter, characterized in that it includes a transmitter filter and the aforementioned receiver filter.

[0029] In one of the aforementioned combined filters, the emitter filter includes a glass substrate, a narrow bandpass film system disposed on one side of the glass substrate, and an antireflection film system disposed on the other side of the glass substrate. The narrow bandpass film system includes alternating layers of hydrogenated silicon / silicon hydroxide / silicon hydride nitrogen film and silicon oxide film. The antireflection film system includes alternating layers of silicon oxide film and hydrogenated silicon / silicon hydroxide / silicon hydride nitrogen film, with silicon oxide film as the outermost layer.

[0030] In one of the aforementioned combined filters, the narrow bandpass film system has the structure (HL)^n, where the H layer is a silicon hydride / silicon hydroxide / silicon hydride layer, the L layer is a silicon oxide layer, and n is the number of cycles in the basic film stack (HL).

[0031] In one of the aforementioned combined filters, the structure of the antireflective film system is L(HL)^n, where the H layer is a silicon hydride / silicon hydroxide / silicon hydride layer, L is a silicon oxide layer, and n is the number of cycles in the basic film stack (HL).

[0032] Compared with existing technologies, this receiver filter and combined filter have the following advantages: the high transmittance band of the receiver filter is in the wavelength range of 1100nm-1800nm:

[0033] 1. The prepared receiver filter has high transmittance with overlapping coverage within an incident angle range of 0°-60°; within the incident angle range of 0°-60°, the cutoff band is required to suppress the passage of light signals; its center wavelength is any wavelength within the range of 1100-1800nm, and the high transmittance band of the receiver filter is within the wavelength range of 1100nm-1800nm; this can greatly improve the characteristics of the passband and cutoff band of the filter, meeting the requirements of camera modules.

[0034] 2. The prepared receiver filter is composed of alternating layers of high-refractive-index silicon hydride / silicon hydroxide / silicon hydride nitride film and low-refractive-index silicon oxide film. The number of film layers is small, and the film thickness can meet the requirements for deposition on two surfaces of an ultra-thin substrate (thickness less than 0.3 mm) to meet the miniaturization requirements of the overall module structure. It can also meet the requirements for operation in low temperature (-40℃), high temperature (+85℃), and high humidity (90%) environments.

[0035] 3. The membrane layer showed no damage under repeated friction with slight external force (pressure <5N), and no damage under repeated wiping with a mixture of alcohol and ether (alcohol: ether = 1:2); after soaking in high-temperature pure water (>95℃) for more than 2 hours, the membrane layer did not peel off after stretching (using CT-18 tape). Attached Figure Description

[0036] Figure 1 This is a flowchart of the method for preparing the receiver filter;

[0037] Figure 2 It is the theoretical transmission spectrum of the narrowband pass of the receiver filter.

[0038] Figure 3 It is the theoretical transmission spectrum of the anti-reflection narrowband filter at the receiving end;

[0039] Figure 4 This is the theoretical transmission spectrum of the receiver filter after both sides are coated.

[0040] Figure 5 This is the transmission spectrum diagram after the performance test of the narrowband filter at the receiving end;

[0041] Figure 6 This is a flowchart of the method for preparing the emitter filter of this combined filter;

[0042] Figure 7 It is the theoretical transmission spectrum of the narrow-band filter at the transmitting end;

[0043] Figure 8 It is the theoretical transmission spectrum of the anti-reflection filter at the transmitter.

[0044] Figure 9 This is the theoretical transmission spectrum of the emitter filter after both sides have been coated.

[0045] Figure 10 This is the transmission spectrum diagram after the performance test of the transmitter filter. Detailed Implementation

[0046] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0047] Example 1

[0048] This embodiment provides a receiver filter structure, including a glass substrate, a narrow bandpass film system disposed on one side of the glass substrate, and an antireflection film system disposed on the other side of the glass substrate. The narrow bandpass film system includes alternating layers of silicon oxide film and silicon hydride / silicon hydroxide / silicon nitride film, with silicon oxide film as the outermost layer. The antireflection film system includes alternating layers of silicon oxide film and silicon hydride / silicon hydroxide / silicon nitride film, with silicon oxide film as the outermost layer.

[0049] In this embodiment, the silicon hydride / silicon hydroxide / silicon hydride nitrogen film layer is a high refractive index film layer, and the silicon oxide film layer is a low refractive index film layer. The structure of the narrow bandpass film system is (LH)^nL, where H layer is a silicon hydride / silicon hydroxide / silicon hydride nitrogen layer, L is a silicon oxide layer, and n is the number of basic film stacks (HL); the structure of the antireflection film system is (LH)^nL, where H layer is a silicon hydride / silicon hydroxide / silicon hydride nitrogen layer, L is a silicon oxide layer, and n is the number of periods of the basic film stacks (HL). Specifically, the structure of the narrow bandpass film system in this embodiment is (LH)^20L, where H layer is a silicon hydride / silicon hydroxide / silicon hydride nitrogen layer, L is a silicon oxide layer, and 20 is the number of basic film stacks (LH); the structure of the antireflection film system is (LH)^4L, where H layer is a silicon hydride / silicon hydroxide / silicon hydride nitrogen layer, L is a silicon oxide layer, and 4 is the number of periods of the basic film stacks (HL). The glass substrate thickness is ≤3mm, and the parallelism of the substrate is <30 degrees. The glass substrate material includes glass, quartz, sapphire, or silicate optical glass. The fabricated receiver filter is composed of alternating layers of high-refractive-index silicon hydride / silicon hydroxide / silicon nitride films and low-refractive-index silicon oxide films. The number of film layers is small, and the film thickness can meet the deposition requirements on both surfaces of an ultra-thin substrate (thickness less than 0.3mm) to meet the miniaturization requirements of the overall module structure. It can also meet the operating requirements of low temperature (-40℃), high temperature (+85℃), and high humidity (90%) environments.

[0050] Specifically, the narrow bandpass film system structure was optimized using optical design software such as Macleod / TFC / Opticlayer, and the optimized structure is shown in Table 1; among them, the film layer with 1 layer is deposited on the glass substrate and is the innermost layer of the narrow bandpass film system; the film layer with 41 layers is the outermost layer of the narrow bandpass film system.

[0051] Table 1. Parameters of Narrow Bandpass Membrane Systems

[0052]

[0053]

[0054] The antireflective coating structure was also optimized using optical design software such as Macleod / TFC / Opticlayer. The optimized structure is shown in Table 2. The innermost layer of the antireflective coating system is deposited on the glass substrate, and the outermost layer of the antireflective coating system is the layer with 1 layer.

[0055] Table 2 Parameters of Anti-reflection Membrane System

[0056]

[0057]

[0058] The prepared receiver filter exhibits high transmittance in the 1320nm-1400nm spectral range within an incident angle range of 0°-60°; it also suppresses light signal transmission in the 400nm-1150nm and 1570nm-1800nm ​​spectral ranges within the same incident angle range; this significantly improves the passband and cutoff band characteristics of the filter, meeting the requirements of camera modules; the film layer remains undamaged under repeated friction with slight external force (pressure <5N), and also remains undamaged under repeated wiping with a mixture of alcohol and ether (alcohol: ether = 1:2); after immersion in high-temperature pure water (>95℃) for more than 2 hours, the film layer does not peel off after stretching (using CT-18 tape).

[0059] The high transmittance band of the prepared receiver filter is in the wavelength range of 1100nm-1800nm; the receiver filter of this embodiment can be used alone in the sensor system without needing to be used in combination with the transmitter filter.

[0060] Example 2

[0061] like Figure 1 As shown, a method for fabricating a receiver filter is provided. This method is implemented in a vacuum sputtering coating machine and includes the following steps:

[0062] Step S01: Place the cleaned glass substrate into a clean low-vacuum chamber and evacuate it to 5.0E-0Pa;

[0063] Step S02: Place the glass substrate into a high vacuum chamber and evacuate it to a certain value below 1.0E-03Pa;

[0064] Step S03: The surface of the glass substrate is bombarded with plasma emitted from a radio frequency source;

[0065] Specifically, the substrate surface is bombarded with plasma emitted from an RF source for 0.5-10 minutes. The RF source power is 1-4 kW, the working gas of the RF source is Ar, and the gas flow rate is 50-500 sccm. The target gas is Ar, and the gas flow rate is 30-300 sccm per pair of targets.

[0066] Step S04: A narrow bandpass film system is deposited on one side of the glass substrate using a magnetron sputtering method. The narrow bandpass film system includes alternating layers of silicon oxide film and silicon hydride / silicon hydroxide / silicon hydride film, as well as an outermost silicon oxide film.

[0067] Step S05: An antireflection film system is deposited on the other side of the glass substrate using a magnetron sputtering method. The antireflection film system includes alternating layers of silicon oxide film and silicon hydride / silicon hydroxide / silicon hydride film, as well as an outermost silicon oxide film.

[0068] Step S06: Allow the glass substrate to cool naturally to room temperature to obtain the receiver filter.

[0069] Step S04 specifically includes:

[0070] Step S041: Deposit silicon oxide film. The second radio frequency oxidation source is activated. The working gas Ar flow rate is 50-500 sccm, the O2 flow rate is 100-500 sccm, the sputtering source power is 5 kW-12 kW, the oxidation source power is 2 kW-4 kW, and the film deposition rate is 0.2-1.2 nm / s.

[0071] Step S042: Deposition of silicon hydride / silicon hydroxide / silicon hydride nitrogen film is performed. The first radio frequency oxidation source is activated, with working gas flow rates of Ar (50-500 sccm), H2 (10-100 sccm), O2 (0-50 sccm), and N2 (0-50 sccm). The sputtering source power is 5 kW-12 kW, the oxidation source power is 1 kW-4 kW, and the film deposition rate is 0.2-0.7 nm / s.

[0072] Step S043, repeat steps S101-S102 in this manner until the last second layer;

[0073] Step S044: The last layer is a silicon oxide film deposited according to step S041.

[0074] The specific structures of the obtained narrowband-pass film system are shown in Table 1 above. Using optical design software such as Macleod / TFC / Opticlayer, the theoretical transmission spectrum of the narrowband-pass film system can be obtained through analysis of the data in Table 1 (e.g., ...). Figure 2 As shown, the narrow bandpass filter system possesses the following characteristics: high transmittance in the 1320nm-1400nm spectral range within the incident angle range of 0°-60°; and the ability to suppress the passage of light signals in the 400nm-1150nm and 1570nm-1800nm ​​spectral ranges.

[0075] Specifically, the sputtering rate of silicon hydride / silicon hydroxide / silicon hydride nitrogen is 0.2-0.7 nm / s, and the sputtering rate of silicon oxide is 0.2-1.2 nm / s; the target material is a silicon target with a purity of 99.999%. Under these conditions, the vacuum sputtering coating machine performs layer-by-layer deposition coating according to steps S041-S044.

[0076] The steps are not limited to filling with oxygen; nitrogen can also be used, with a nitrogen volume of 0-50 sccm; or no gas may be filled. Whether to dope with other gases or not is aimed at ensuring that the prepared filter meets the refractive index requirements of this invention.

[0077] Step S05 specifically includes:

[0078] Step S051: Deposit silicon oxide film. The second radio frequency oxidation source is activated. The working gas Ar flow rate is 50-500 sccm, the O2 flow rate is 100-500 sccm, the sputtering source power is 5 kW-12 kW, the oxidation source power is 2 kW-4 kW, and the film deposition rate is 0.2-1.2 nm / s.

[0079] Step S052: Deposition of silicon hydride / silicon hydroxide / silicon hydride nitrogen film is performed. The first radio frequency oxidation source is activated. The working gas flow rate is 50-500 sccm, H2 flow rate is 10-100 sccm, O2 flow rate is 0-50 sccm, N2 flow rate is 0-50 sccm, sputtering source power is 5 kW-12 kW, oxidation source power is 1 kW-4 kW, and film deposition rate is 0.2-0.7 nm / s.

[0080] Step S053, repeat steps S051-S052 in this manner until the last second layer;

[0081] Step S054: The last layer is a silicon oxide film deposited according to step S051.

[0082] The specific structures of the obtained antireflective coating system are shown in Table 2 above. Using optical design software such as Macleod / TFC / Opticlayer, the theoretical transmission spectrum of the antireflective coating system can be obtained through analysis of the data in Table 2 (e.g., ...). Figure 3 As shown in the figure, the results indicate that the antireflective coating system has high transmittance in the 1300nm-1450nm spectral range when the incident angle is 0°-60°.

[0083] Specifically, the sputtering rate of silicon hydride / silicon hydroxide / silicon hydride nitrogen is 0.2-0.7 nm / s, and the sputtering rate of silicon oxide is 0.2-1.2 nm / s; the target material is a silicon target with 99.999% purity. Under these conditions, the vacuum sputtering coating machine performs layer-by-layer deposition according to steps S051-S054.

[0084] The steps are not limited to filling with oxygen; nitrogen can also be used, with a nitrogen volume of 0-50 sccm; or no gas may be filled. Whether to dope with other gases or not is aimed at ensuring that the prepared filter meets the refractive index requirements of this invention.

[0085] Ultimately, the receiver filter prepared by this embodiment exhibits high transmittance within an incident angle range of 0°-60° and a bandwidth of (20nm-150nm), such as the 1320nm-1400nm spectral range. In other spectral ranges, such as the 400nm-1150nm and 1570nm-1800nm ​​spectral ranges, it suppresses light signal transmission. The high transmittance band of the receiver filter is within the wavelength range of 1100nm-1800nm. Finally, the theoretical transmission spectrum of the receiver filter after double-sided coating can be obtained, as shown below. Figure 4 As shown.

[0086] Specifically, the receiver filter prepared in this embodiment was fabricated using an NSP-1650 vacuum sputtering coating machine from Kokkuri Co., Ltd. of Japan. The specific steps are as follows:

[0087] (1) Use a vacuum cleaner to remove impurities from the LL vacuum chamber of the coating machine. Install the clean glass substrate that has been ultrasonically cleaned onto the coating fixture and quickly put it into the clean vacuum chamber. Evacuate to 5.0EPa. Exchange the coating fixture to the PR film forming chamber and evacuate to a certain value below 1.0E-3Pa to start film forming.

[0088] (2) The substrate surface is bombarded with plasma emitted from a radio frequency source for 0.5-10 minutes. The power of the radio frequency source is 2-4 kW, the working gas of the radio frequency source is Ar, and the gas flow rate is 50-500 sccm. The target gas is Ar, and the gas flow rate is 30-300 sccm per pair of targets.

[0089] (3) Using magnetron sputtering, silicon oxide film and silicon hydrogen hydroxide / silicon hydrogen nitride film in narrow bandpass film system are deposited alternately layer by layer on one side of the substrate until the deposition of the film system is completed; silicon oxide film and silicon hydrogen hydroxide / silicon hydrogen nitride film in antireflection film system on the other side of the substrate are deposited alternately layer by layer on the other side until the deposition of the film system is completed.

[0090] (4) The substrate is naturally cooled to room temperature to obtain a near-infrared high-transmittance narrow-band receiver filter of this embodiment.

[0091] (5) The following performance tests were performed on the prepared receiver filter: The transmission spectrum of the receiver filter was measured using an Agilent Technologies Cary 7000 general-purpose spectrophotometer (e.g., ...). Figure 5(As shown). Within an incident angle range of 0°-60°, the filter exhibits a minimum transmittance greater than 90% in the 1320nm-1400nm spectral band; a maximum average transmittance of less than 5% in the 400nm-1150nm and 1570nm-1800nm ​​spectral bands across multiple angles; and a maximum average transmittance of less than 0.5% in the 750nm-1154nm and 1569nm-1750nm spectral bands across multiple angles. In these spectral specifications, the center wavelength can be any wavelength within the 1100-1800nm ​​band that matches the transmitter. The transmittance bandwidth can be widened or narrowed, and the cutoff wavelength can be varied for optimized design. However, the spectral specifications described above are not limited to these specifications; variations in transmittance bandwidth and cutoff wavelength are also possible.

[0092] Example 3

[0093] This embodiment provides a combined filter, including an emitter filter and a receiver filter as described in Embodiment 1. The emitter filter includes a glass substrate, a narrow bandpass film system disposed on one side of the glass substrate, and an antireflection film system disposed on the other side of the glass substrate. The narrow bandpass film system includes alternating layers of hydrogenated silicon / silicon hydroxide / silicon nitride film and silicon oxide film. The antireflection film system includes alternating layers of silicon oxide film and hydrogenated silicon / silicon hydroxide / silicon nitride film, with silicon oxide film as the outermost layer. The thickness of the glass substrate is less than ≤0.3mm, and the parallelism of the substrate is <30 degrees. The material of the glass substrate includes glass, quartz, sapphire, or silicate optical glass.

[0094] The narrowband pass film system has the structure (HL)^n, where the H layer is a silicon hydride / silicon hydroxide / silicon hydride nitrogen layer, L is a silicon oxide layer, and n is the number of cycles in the basic film stack (HL). The antireflection film system has the structure L(HL)^n, where the H layer is a silicon hydride / silicon hydroxide / silicon hydride nitrogen layer, L is a silicon oxide layer, and n is the number of cycles in the basic film stack (HL). Specifically, in this embodiment, the narrowband pass film system has the structure (HL)^17, where the H layer is a silicon hydride / silicon hydroxide / silicon hydride nitrogen layer, L is a silicon oxide layer, and 17 is the number of cycles in the basic film stack (HL). The antireflection film system has the structure L(HL)^3, where the H layer is a silicon hydride / silicon hydroxide / silicon hydride nitrogen layer, L is a silicon oxide layer, and 3 is the number of cycles in the basic film stack (HL).

[0095] Among them, such as Figure 6 As shown, the method for fabricating the emitter filter is implemented in a vacuum sputtering coating machine, and the specific steps include the following:

[0096] Step S1: Place the cleaned glass substrate into a clean low-vacuum chamber and evacuate to 5.0E-0Pa;

[0097] Step S2: The glass substrate is moved into the high vacuum chamber and evacuated to a certain value below 1.0E-03Pa;

[0098] Step S3: The surface of the glass substrate is bombarded with plasma emitted from a radio frequency source;

[0099] Specifically, the substrate surface is bombarded with plasma emitted from a radio frequency source for 0.5-10 minutes. The power of the radio frequency source is 1-4 kW, the working gas of the radio frequency source is Ar, and the gas flow rate is 50-500 sccm. The target gas is Ar, and the gas flow rate is 30-300 sccm per pair of targets.

[0100] Step S4: A narrow bandpass film system is deposited on one side of the glass substrate using a magnetron sputtering method. The narrow bandpass film system includes alternating layers of hydrogenated silicon / silicon hydroxide / silicon hydride and silicon oxide.

[0101] Step S5: An antireflection film system is deposited on the other side of the glass substrate using a magnetron sputtering method. The antireflection film system includes alternating layers of silicon oxide film and silicon hydride / silicon hydroxide / silicon hydride film, as well as an outermost silicon oxide film.

[0102] Step S6: Allow the glass substrate to cool naturally to room temperature to obtain the emitter filter.

[0103] Step S4 specifically includes:

[0104] Step S41: Deposition of silicon hydride / silicon hydroxide / silicon hydride nitrogen film is performed. The first radio frequency oxidation source is activated, with working gas flow rates of 50-500 sccm, H2 flow rates of 10-100 sccm, O2 flow rates of 0-50 sccm, and N2 flow rates of 0-50 sccm. The sputtering source power is 5 kW-12 kW, the oxidation source power is 1 kW-4 kW, and the film deposition rate is 0.2-0.7 nm / s.

[0105] Step S42: Deposit silicon oxide film. The second radio frequency oxidation source is activated. The working gas Ar flow rate is 50-500 sccm, the O2 flow rate is 100-500 sccm, the sputtering source power is 5 kW-12 kW, the oxidation source power is 2 kW-4 kW, and the film deposition rate is 0.2-1.2 nm / s.

[0106] Step S43: Repeat steps S41-S42 in this manner until the last layer.

[0107] Specifically, the sputtering rate of silicon hydride / silicon hydroxide / silicon hydride nitrogen is 0.2-0.7 nm / s, and the sputtering rate of silicon oxide is 0.2-1.2 nm / s; the target material is a silicon target with 99.999% purity. Under these conditions, the vacuum sputtering coating machine performs layer-by-layer deposition according to steps S41-S43.

[0108] The steps are not limited to filling with oxygen; nitrogen can also be used, with a nitrogen volume of 0-50 sccm; or no gas may be filled. Whether to dope with other gases or not is aimed at ensuring that the prepared filter meets the refractive index requirements of this invention.

[0109] The structure of the narrow bandpass film system was optimized using optical design software such as Macleod / TFC / Opticlayer. The resulting narrow bandpass film system is shown in Table 3. The film with 1 layer is deposited on the glass substrate and is the innermost layer of the narrow bandpass film system. The film with 38 layers is the outermost layer of the narrow bandpass film system.

[0110] Table 3. Parameters of Narrow Bandpass Membrane Systems

[0111]

[0112]

[0113] The theoretical transmission spectrum of the bandpass film system can be obtained by analyzing the data in Table 3 using optical design software such as Macleod / TFC / Opticlayer, as shown below. Figure 7 As shown, the results indicate that the narrow bandpass film system possesses the following characteristics: high transmittance in the 1333nm-1424nm spectral range within the incident angle range of 0°-45°; suppression of light signal transmission in the 400nm-1220nm and 1550nm-1720nm spectral ranges; and high transmittance in the 1360nm-1400nm spectral range within the incident angle range of 45°-60°.

[0114] Step S5 specifically includes:

[0115] Step S51: Deposit silicon oxide film. The second radio frequency oxidation source is activated. The working gas Ar flow rate is 50-500 sccm, the O2 flow rate is 100-500 sccm, the sputtering source power is 5 kW-12 kW, the oxidation source power is 2 kW-4 kW, and the film deposition rate is 0.2-1.2 nm / s.

[0116] Step S52: Deposition of silicon hydride / silicon hydroxide / silicon hydride nitrogen film is performed. The first radio frequency oxidation source is activated, with working gas Ar flow rate of 50-500 sccm, H2 flow rate of 10-100 sccm, O2 flow rate of 0-50 sccm / N2 flow rate of 0-50 sccm, sputtering source power of 5 kW-12 kW, oxidation source power of 1 kW-4 kW, and film deposition rate of 0.2-0.7 nm / s.

[0117] Step S53: Repeat steps S51-S52 in this manner until the last second layer;

[0118] Step S54: The final layer is a silicon oxide film deposited according to step S51.

[0119] Specifically, the sputtering rate of silicon hydride / silicon hydroxide / silicon hydride nitrogen is 0.2-0.7 nm / s, and the sputtering rate of silicon oxide is 0.2-1.2 nm / s; the target material is a silicon target with 99.999% purity. Under these conditions, the vacuum sputtering coating machine performs layer-by-layer deposition according to steps S51-S54.

[0120] The steps are not limited to filling with oxygen; nitrogen can also be used, with a nitrogen volume of 0-50 sccm; or no gas may be filled. Whether to dope with other gases or not is aimed at ensuring that the prepared filter meets the refractive index requirements of this invention.

[0121] The structure of the antireflective coating system was optimized using optical design software such as Macleod / TFC / Opticlayer, and the resulting antireflective coating system is shown in Table 4. Among them, the film layer with a number of 1 layers is deposited on the glass substrate and is the innermost layer of the antireflective coating system; the film layer with a number of 7 layers is the outermost layer of the antireflective coating system.

[0122] Table 4. Parameters of Antireflective Membrane Systems

[0123]

[0124] The theoretical transmission spectrum of the antireflection coating system can be obtained by analyzing the data in Table 4 using optical design software such as Macleod / TFC / Opticlayer (e.g., Figure 8 As shown in the figure, the results show that the antireflective film system has the following characteristics: when the incident angle is 0°-45°, the antireflective film system has high transmittance in the 1300nm-1450nm spectral range; when the incident angle is 45°-60°, the antireflective film system has high transmittance in the 1360nm-1400nm spectral range.

[0125] After the double-sided coating is completed, the theoretical transmission spectrum of the emitter filter is obtained, such as... Figure 9 As shown.

[0126] The prepared emitter filter has the following characteristics:

[0127] (1) The spectral range of 1333nm-1424nm has high transmittance within the incident angle range of 0°-45°;

[0128] (2) Within the incident angle range of 0°-45°, it has the effect of suppressing the passage of light signals in the 400nm-1220nm and 1550nm-1720nm spectral bands.

[0129] (3) The transmittance in the 1333nm-1424nm spectral range has small variations within the incident angle range of 0°-45°.

[0130] (4) The filter is composed of alternating layers of high-refractive-index silicon hydride / silicon hydroxide / silicon nitride film and low-refractive-index silicon oxide film. The number of film layers is small and the film thickness can meet the requirements for deposition on two surfaces of an ultra-thin substrate (thickness less than 0.3 mm). The filter meets the requirements for operation in low temperature (-40℃), high temperature (+85℃) and high humidity (90%) environments.

[0131] Specifically, in this embodiment, the transmitter filter is prepared using an NSP-1650 vacuum sputtering coating machine from Kokkuri Co., Ltd. of Japan. The specific steps are as follows:

[0132] 1. Use a vacuum cleaner to remove impurities from the LL vacuum chamber of the coating machine. Install the clean glass substrate, which has been ultrasonically cleaned, onto the coating fixture and quickly place it into the clean vacuum chamber. Evacuate the vacuum to 5.0 EPa. Then, transfer the coating fixture to the PR film-forming chamber and evacuate the vacuum to a certain value below 1.0 E-3 Pa to begin film formation.

[0133] 2. Bombard the substrate surface with plasma emitted from an RF source for 0.5-10 minutes. The RF source power is 2-4 kW, the working gas of the RF source is Ar, and the gas flow rate is 50-500 sccm. The target gas is Ar, and the gas flow rate is 30-300 sccm per pair of targets.

[0134] 3. Using magnetron sputtering, alternately deposit layers of silicon hydride / silicon hydroxide / silicon nitride and silicon oxide in a narrow bandpass film system on one side of the substrate until the deposition of the film system is completed; alternately deposit layers of silicon oxide and silicon hydride / silicon hydroxide / silicon nitride in an antireflection film system on the other side of the substrate until the deposition of the film system is completed.

[0135] 4. The substrate is allowed to cool naturally to room temperature to obtain a narrow-band emitter filter with high near-infrared transmittance.

[0136] 5. The following performance tests were performed on the filter: The transmission spectrum of the filter was measured using an Agilent Technologies Cary 7000 general-purpose spectrophotometer (e.g., ...). Figure 10(As shown). This filter exhibits a minimum transmittance greater than 90% in the 1333nm-1424nm spectral range within an incident angle range of 0°-45°; a maximum average transmittance of less than 2.5% in the 400nm-1220nm and 1550nm-1720nm spectral ranges across multiple angles; and a minimum transmittance greater than 90% in the 1360nm-1400nm spectral range within an incident angle range of 45°-60°. These spectral specifications are not limited to these limits. Any wavelength within the 1100-1800nm ​​band that matches the receiver can be used for optimization design modifications, such as widening or narrowing the transmission bandwidth and varying the cutoff wavelength. The aforementioned spectral specifications, including variations in transmission bandwidth and cutoff wavelength, can all be achieved.

[0137] The combined filter of this embodiment achieves excellent technical specifications: the emitting filter has high transmittance in the 1333nm-1424nm spectral range within an incident angle range of 0°-45°; and it suppresses light signal transmission in the 400nm-1220nm and 1550nm-1720nm spectral ranges. The receiving filter has high transmittance in the 1320nm-1400nm spectral range within an incident angle range of 0°-60°; and it suppresses light signal transmission in the 400nm-1150nm and 1570nm-1800nm ​​spectral ranges. This significantly improves the passband and cutoff band characteristics of the filters in these spectral ranges, meeting the requirements of camera modules. Since the emitting and receiving filters share a common transmission bandpass, this combined filter can be used in various sensor systems, but is not limited to sensor systems.

[0138] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A receiver filter, comprising a glass substrate, a narrow bandpass film system disposed on one side of the glass substrate, and an antireflection film system disposed on the other side of the glass substrate, wherein the narrow bandpass film system comprises alternating layers of silicon oxide and silicon hydroxide / silicon hydride / hydrogen nitride film, and an outermost silicon oxide film layer; the antireflection film system comprises alternating layers of silicon oxide and silicon hydroxide / silicon hydride / hydrogen nitride film, and an outermost silicon oxide film layer; the structure of the narrow bandpass film system is (LH)^20L, where H layer is a silicon hydroxide / silicon hydroxide / silicon hydride / hydrogen nitride layer, L is a silicon oxide layer, and 20 is the number of basic film stacks (HL); the structure of the antireflection film system is (LH)^4L, where H layer is a silicon hydroxide / silicon hydroxide / silicon hydride / hydrogen nitride layer. L represents the silicon oxide layer, and 4 represents the number of cycles in the basic film stack (HL). The receiving filter is used to achieve a transmittance of ≥90% in the 1320nm-1400nm spectral range when the incident angle is within the range of 0°-60°, and to suppress the passage of light signals in the 400nm-1150nm and 1570nm-1800nm ​​spectral ranges.

2. The receiving-end filter according to claim 1, characterized in that, The thickness of the glass substrate is ≤3mm.

3. A method for preparing a receiver filter, used to prepare the receiver filter according to any one of claims 1-2, characterized in that, Includes the following steps: Step S01: Place the glass substrate into the low vacuum chamber and evacuate it; Step S02: Place the glass substrate into the high vacuum chamber and evacuate it; Step S03: The surface of the glass substrate is bombarded with plasma emitted from a radio frequency source; Step S04: A narrow bandpass film system is deposited on one side of a glass substrate using a magnetron sputtering method. The narrow bandpass film system includes alternating layers of silicon oxide film and silicon hydride / silicon hydroxide / silicon hydride film, as well as an outermost silicon oxide film. Step S05: An antireflection film system is deposited on the other side of the glass substrate using a magnetron sputtering method. The antireflection film system includes alternating layers of silicon oxide film and silicon hydride / silicon hydroxide / silicon hydride film, as well as an outermost silicon oxide film. Step S06: Allow the glass substrate to cool naturally to room temperature to obtain the receiver filter.

4. The method for preparing a receiving-end filter according to claim 3, characterized in that, Step S04 specifically includes: Step S041: Deposit silicon oxide film. The second radio frequency oxidation source is activated. The working gas Ar flow rate is 50-500 sccm, the O2 flow rate is 100-500 sccm, the sputtering source power is 5 kW-12 kW, the oxidation source power is 2 kW-4 kW, and the film deposition rate is 0.2-1.2 nm / s. Step S042: Deposition of silicon hydride / silicon hydroxide / silicon hydride nitrogen film is performed. The first radio frequency oxidation source is activated, with working gas flow rates of Ar (50-500 sccm), H2 (10-100 sccm), O2 (0-50 sccm), and N2 (0-50 sccm). The sputtering source power is 5 kW-12 kW, the oxidation source power is 1 kW-4 kW, and the film deposition rate is 0.2-0.7 nm / s. Step S043, repeat steps S041-S042 in this manner until the last second layer; Step S044: The last layer is a silicon oxide film deposited according to step S041.

5. The method for preparing a receiving-end filter according to claim 3, characterized in that, Step S05 specifically includes: Step S051: Deposit silicon oxide film. The second radio frequency oxidation source is activated. The working gas Ar flow rate is 50-500 sccm, the O2 flow rate is 100-500 sccm, the sputtering source power is 5 kW-12 kW, the oxidation source power is 2 kW-4 kW, and the film deposition rate is 0.2-1.2 nm / s. Step S052: Deposition of silicon hydride / silicon hydroxide / silicon hydride nitrogen film is performed. The first radio frequency oxidation source is activated. The working gas flow rate is 50-500 sccm, H2 flow rate is 10-100 sccm, O2 flow rate is 0-50 sccm, N2 flow rate is 0-50 sccm, sputtering source power is 5 kW-12 kW, oxidation source power is 1 kW-4 kW, and film deposition rate is 0.2-0.7 nm / s. Step S053, repeat steps S051-S052 in this manner until the last second layer; Step S054: The last layer is a silicon oxide film deposited according to step S051.

6. A combined filter, characterized in that, It includes the transmitter filter and any of the receiver filters described in claims 1-5 above.

7. A combined filter according to claim 6, characterized in that, The emitter filter includes a glass substrate, a narrow bandpass film system disposed on one side of the glass substrate, and an antireflection film system disposed on the other side of the glass substrate. The narrow bandpass film system includes alternating layers of hydrogenated silicon / silicon hydroxide / silicon nitride film and silicon oxide film. The antireflection film system includes alternating layers of silicon oxide film and hydrogenated silicon / silicon hydroxide / silicon nitride film, and an outermost silicon oxide film.

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