Lens module optical filter and preparation method and application thereof

Abstract

The invention relates to a lens module optical filter and a preparation method and application thereof. The film comprises a substrate, a basic film system, an IR film system and an AR film system, the basic film system is located on one side of the substrate, the IR film system is located on the upper side of the basic film system, and the AR film system is located on the other side, opposite to the basic film system, of the substrate; the film system structure of the optical filter is (LH) mMLSub (HL) n, and the working wave band is 700-1100 nm; wherein Sub is a substrate, (LH) m is an IR film system, ML is a basic film system, (HL) n is an AR film system, m is 3-4, and n is 19-21. The preparation method comprises the steps of substrate selection and pretreatment, spin coating, ion-assisted deposition coating and post-treatment. The working wave band of the optical filter of the lens module provided by the invention is 700-1100 nm, the wave band cut-off rate greater than 99% can be realized in the wavelength range, and the purity and the detection precision of an infrared signal are improved; and the infrared light and visible light transmittance is greater than 90%, so that the requirement of a multi-band optical system on simultaneous and efficient transmission of visible light and infrared light is met, and the problems of poor band cut-off characteristic and low visible light transmittance of part of IR sheets in the market are solved.

Description

Technical Field

[0001] The present application relates to the technical field of optical elements, and in particular to a lens module filter, a preparation method thereof, and an application thereof. Background Art

[0002] Infrared optical materials and their applications, especially infrared filters, play a crucial role in modern optical technology. With the rapid advancement of science and technology, infrared technology has been widely applied in numerous fields, such as security monitoring, medical imaging, industrial inspection, and consumer electronics. These applications place increasingly stringent demands on the performance of infrared filters. They must not only possess high transmittance within specific infrared bands to accurately capture target infrared signals, but also effectively block interference from light in other bands to ensure imaging quality and detection accuracy.

[0003] Currently, IR chips on the market have certain performance limitations. While some IR chips can transmit signals within certain infrared bands, their cutoff characteristics are suboptimal. Outside the operating band, they are unable to effectively suppress the transmission of stray light, resulting in a low cutoff rate, typically below 99%. This low cutoff rate introduces a large amount of interfering signals, making infrared imaging systems susceptible to image blur and noise interference in complex environments. This severely impacts the accuracy of target recognition and feature extraction, reducing system reliability and stability.

[0004] On the other hand, some IR films often sacrifice visible light transmittance when pursuing infrared cutoff performance. This low visible light transmittance, typically less than 80%, limits their use in applications that require simultaneous utilization of both visible and infrared light information. For example, some security monitoring equipment requires both clear scene images using visible light and infrared monitoring capabilities for nighttime or low-light conditions. Existing IR films cannot simultaneously meet the requirements for both high visible light transmittance and high infrared cutoff, resulting in suboptimal device performance and impacting user experience and application effectiveness. Summary of the Invention

[0005] To solve the above-mentioned problems, the present application provides a lens module filter, a preparation method and an application thereof. The working band of the filter is 700-1100nm. It can not only achieve a band cutoff rate greater than 99% within this wavelength range, effectively block light interference outside the working band, and improve the purity and detection accuracy of infrared signals; at the same time, it also has a visible light transmittance greater than 90%, meeting the needs of multi-band optical systems for simultaneous and efficient transmission of visible light and infrared light.

[0006] In the first aspect, the present application provides a lens module filter adopting the following technical solution: A lens module filter, comprising a substrate, a base film system, an IR film system, and an AR film system, wherein the base film system is located on one side of the substrate, the IR film system is located above the base film system, and the AR film system is located on the other side of the substrate opposite to the base film system; The film structure of the lens module filter is (LH) m ML|Sub|(HL) n , the operating band is 700-1100nm; Where Sub is the base, (LH) m IR film system, ML is the basic film system, (HL) n It is an AR film system, m is 3-4, and n is 19-21.

[0007] Furthermore, the film structure H is a Ti3O5 film layer, L is a low-refractive-index material SiO2 film layer, and ML is a MgF2 film layer.

[0008] Optionally, the substrate is selected from one of sapphire glass, JB510, CB535, HB850, colorless optical glass K9, float glass, B270, and fused quartz.

[0009] Furthermore, the IR film system includes 8 layers of high-refractive-index film layers and low-refractive-index film layers alternately stacked in sequence from the basic film system outward according to the IR film system structure, and the geometric thickness values ​​of the 1st to 8th layers are: 220nm for the 1st layer, 250nm for the 2nd layer, 210nm for the 3rd layer, 280nm for the 4th layer, 230nm for the 5th layer, 260nm for the 6th layer, 205nm for the 7th layer, and 295nm for the 8th layer.

[0010] Furthermore, the AR film system includes 40 layers of high refractive index film layers and low refractive index film layers alternately stacked from the substrate outward according to the AR film system structure, and the geometric thickness values ​​of the 1st to 40th layers are: 135nm for the 1st layer, 128nm for the 2nd layer, 132nm for the 3rd layer, 125nm for the 4th layer, 138nm for the 5th layer, 122nm for the 6th layer, 130nm for the 7th layer, 127nm for the 8th layer, 136nm for the 9th layer, 120nm for the 11th layer, 133nm for the 12th layer, 129nm for the 13th layer, 131nm for the 14th layer, 124nm for the 15th layer, 137nm for the 16th layer, 126nm for the 17th layer, 134nm for the 18th layer, The 8th layer is 121nm, the 19th layer is 139nm, the 20th layer is 123nm, the 21st layer is 130nm, the 22nd layer is 128nm, the 23rd layer is 135nm, the 24th layer is 126nm, the 25th layer is 132nm, the 26th layer is 127nm, the 27th layer is 138nm, the 28th layer is 124nm, the 29th layer is 131nm, the 30th layer is 129nm, the 31st layer is 136nm, the 32nd layer is 122nm, the 33rd layer is 133nm, the 34th layer is 125nm, the 35th layer is 137nm, the 36th layer is 123nm, the 37th layer is 134nm, the 38th layer is 120nm, the 39th layer is 139nm, and the 40th layer is 121nm.

[0011] Furthermore, the basic film system includes a MgF2 film layer plated from the substrate outward according to the basic film system structure, and its geometric thickness is 69nm.

[0012] In a second aspect, the present application provides a method for preparing a lens module filter using the following technical solution: A method for preparing a lens module filter comprises the following steps: S1. Substrate selection and pretreatment: Select sapphire glass or other optical glass as the substrate, remove surface particles and organic matter by ultrasonic cleaning, and dehydrate and bake at 150-250°C to remove moisture and organic matter on the substrate surface; S2, spin coating: the prepared spin coating liquid is dropped on the center of the substrate. During the high-speed rotation of the substrate, the centrifugal force causes the droplet to evenly spread over the entire substrate surface. After coating, the spin coating liquid is allowed to stand to fully react with the substrate to form a functional layer; S3, film coating: placing the substrate obtained after spin coating in S2 in a vacuum chamber, and coating the film by ion-assisted deposition at a pressure of 1.03-2.03 Pa and a temperature of 100-120° C. The film thickness is monitored in real time by a quartz crystal microbalance; S4, post-processing: the coated substrate is cleaned twice to remove the coating residue, and then the optical performance of the filter is verified.

[0013] In a third aspect, the present application provides an application of a lens module filter using the following technical solutions: The above-mentioned lens module filter and / or the filter prepared by the above-mentioned method for preparing a lens module filter can be assembled with IR-CUT, thereby being applied to the recognition module of the smart door lock.

[0014] In summary, this application has the following beneficial effects: 1. The lens module filter provided in this application operates in the 700-1100nm wavelength band. It not only achieves a band cutoff rate greater than 99% within this wavelength range, effectively blocking interference from light outside the operating band and improving infrared signal purity and detection accuracy, but also boasts a visible light transmittance greater than 90%, meeting the requirements of multi-band optical systems for efficient simultaneous transmission of visible and infrared light. This addresses the issues of some IR filters on the market with their poor band cutoff characteristics and low visible light transmittance. 2. The lens module filter prepared in this application can be assembled with IR-CUT and applied to the door lock recognition module. In actual use, it can be driven by electromagnetic means to realize the automatic conversion of day and night filter modes, thereby achieving a balance between restoring true colors and enhancing infrared sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 Schematic diagram of the basic structure of the lens module filter in the embodiment of the present application; Figure 2 This is the transmittance-wavelength curve of the lens module filter in the embodiment of the present application. DETAILED DESCRIPTION

[0017] To more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. It should be understood that the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Example

[0018] Please refer to the attached Figure 1 and attached Figure 2A lens module filter with an operating band of 700-1100nm includes a substrate, a base film system, an IR film system, and an AR film system. The base film system is located on one side of the substrate, the IR film system is located on the upper side of the base film system, and the AR film system is located on the other side of the substrate opposite to the base film system. The IR film system includes 8 layers of high refractive index film layers and low refractive index film layers alternately stacked from the base film system outward according to the IR film system structure. The structure of the IR film system is: ML / 220nmH, 250nmL, 210nmH, 280nmL, 230nmH, 260nmL, 205nmH, 295nmL / air; The AR film system includes 40 layers of high refractive index film layers and low refractive index film layers which are alternately stacked from the base to the outside according to the AR film system structure. The structure of the AR film system is: base / 135nmH, 128nmL, 132nmH, 125nmL, 138nmH, 122nmL, 130nmH, 127nmL, 136nmH, 120nmL, 133nmH, 129nmL, 131nmH, 124nmL, 137nmH, 126nmL, 13 4 nmH, 121 nmL, 139 nmH, 123 nmL, 130 nmH, 128 nmL, 135 nmH, 126 nmL, 132 nmH, 127 nmL, 138 nmH, 124 nmL, 131 nmH, 129 nmL, 136 nmH, 122 nmL, 133 nmH, 125 nmL, 137 nmH, 123 nmL, 134 nmH, 120 nmL, 139 nmH, 121 nmL / air; The basic film system includes a layer of MgF2 film plated from the substrate outward according to the basic film system structure. The structure of the basic film system is: substrate / 69nmML / IR film system; Wherein, H is a high refractive index film layer, L is a low refractive index film layer, in this embodiment, H is a Ti3O5 film layer, L is a SiO2 film layer, and the substrate is a sapphire substrate; And prepared by the following method: S1. Substrate pretreatment: Place the sapphire glass in an ultrasonic tank and use ultrasonic cleaning to remove surface particles and organic matter. Then, dehydrate and bake at 150-250°C to remove moisture and organic matter from the substrate surface. S2, spin coating: the prepared spin coating liquid is dropped on the center of the substrate. During the high-speed rotation of the substrate, the centrifugal force causes the droplet to evenly spread over the entire substrate surface. After coating, the spin coating liquid is allowed to stand to fully react with the substrate to form a functional layer; S3, film coating: the substrate obtained after spin coating in S2 is placed in a vacuum chamber and coated by ion-assisted deposition at a pressure of 1.03-2.03 Pa. The purity of MgF2, Ti3O5 and SiO2 targets are all ≥99.99%. The temperature is 100-120°C, and the film thickness is monitored in real time by a quartz crystal microbalance; S4, post-processing: the coated substrate is cleaned twice to remove the coating residue, and then the optical performance of the filter is verified.

[0019] The optical performance of the lens module filter obtained in the embodiment of the present application after double-sided coating was measured, and its transmittance-wavelength curve was referenced to Figure 2 , it can be seen that the cutoff rate of the band in the range of 700-1100nm is greater than 99%, while the transmittance of visible light is greater than 90%.

[0020] In addition, the lens module filter obtained in the embodiment of the present application can also be assembled with IR-CUT and applied to the door lock recognition module. In actual application, the automatic switching of day and night filter modes is realized through electromagnetic drive. During the day, the infrared cutoff filter is enabled to restore the true color, and at night it is switched to full-spectrum transparent glass to enhance infrared sensitivity.

[0021] The above are all modifications that a person skilled in the art can make to this embodiment as needed after reading this specification, which do not contribute creatively or solutions that obviously constitute technical inspiration. However, as long as they are within the scope of the claims of this application, they should be protected by patent law.

Claims

1. A lens module filter, characterized in that: The invention comprises a substrate, a base film system, an IR film system and an AR film system, wherein the base film system is located on one side of the substrate, the IR film system is located on the upper side of the base film system, and the AR film system is located on the other side of the substrate opposite to the base film system; The film structure of the lens module filter is (LH) m ML|Sub|(HL) n , the operating band is 700-1100nm; Where Sub is the base, (LH) m IR film system, ML is the basic film system, (HL) n It is an AR film system, m is 3-4, and n is 19-21.

2. The lens module filter according to claim 1, characterized in that: The film structure H is a Ti3O5 film layer, L is a low-refractive-index material SiO2 film layer, and ML is a MgF2 film layer.

3. The lens module filter according to claim 1, wherein: The substrate is selected from one of sapphire glass, JB510, CB535, HB850, colorless optical glass K9, float glass, B270, and fused quartz.

4. The lens module filter according to claim 1, wherein: The IR film system includes 8 layers of high-refractive-index film layers and low-refractive-index film layers alternately stacked from the basic film system outward according to the IR film system structure. The geometric thickness values ​​of layers 1-8 are: 220nm for the first layer, 250nm for the second layer, 210nm for the third layer, 280nm for the fourth layer, 230nm for the fifth layer, 260nm for the sixth layer, 205nm for the seventh layer, and 295nm for the eighth layer.

5. The lens module filter according to claim 1, wherein: The AR film system includes 40 layers of high refractive index film layers and low refractive index film layers alternately stacked from the substrate to the outside according to the AR film system structure, and the geometric thickness values ​​of the 1st to 40th layers are: 135nm for the 1st layer, 128nm for the 2nd layer, 132nm for the 3rd layer, 125nm for the 4th layer, 138nm for the 5th layer, 122nm for the 6th layer, 130nm for the 7th layer, 127nm for the 8th layer, 136nm for the 9th layer, 120nm for the 11th layer, 133nm for the 12th layer, 129nm for the 13th layer, 131nm for the 14th layer, 124nm for the 15th layer, 137nm for the 16th layer, 126nm for the 17th layer, 134nm for the 18th layer, 21nm, the 19th layer is 139nm, the 20th layer is 123nm, the 21st layer is 130nm, the 22nd layer is 128nm, the 23rd layer is 135nm, the 24th layer is 126nm, the 25th layer is 132nm, the 26th layer is 127nm, the 27th layer is 138nm, the 28th layer is 124nm, the 29th layer is 131nm, the 30th layer is 129nm, the 31st layer is 136nm, the 32nd layer is 122nm, the 33rd layer is 133nm, the 34th layer is 125nm, the 35th layer is 137nm, the 36th layer is 123nm, the 37th layer is 134nm, the 38th layer is 120nm, the 39th layer is 139nm, and the 40th layer is 121nm.

6. The lens module filter according to claim 1, wherein: The basic film system includes a MgF2 film layer plated from the base outward according to the basic film system structure, and the geometric thickness thereof is 69 nm.

7. The method for preparing a lens module filter according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Substrate selection and pretreatment: Select sapphire glass or other optical glass as the substrate, remove surface particles and organic matter by ultrasonic cleaning, and dehydrate and bake at 150-250°C to remove moisture and organic matter on the substrate surface; S2, spin coating: the prepared spin coating liquid is dropped on the center of the substrate. During the high-speed rotation of the substrate, the centrifugal force causes the droplet to evenly spread over the entire substrate surface. After coating, the spin coating liquid is allowed to stand to fully react with the substrate to form a functional layer; S3, film coating: placing the substrate obtained after spin coating in S2 in a vacuum chamber, and coating the film by ion-assisted deposition at a pressure of 1.03-2.03 Pa and a temperature of 100-120° C. The film thickness is monitored in real time by a quartz crystal microbalance; S4, post-processing: the coated substrate is cleaned twice to remove the coating residue, and then the optical performance of the filter is verified.

8. Use of the lens module filter according to any one of claims 1 to 6 and / or the filter produced by the method for producing a lens module filter according to claim 7 in an identification module of a smart door lock.

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