Optical filter applied to medical communication sapphire window

Abstract

The invention relates to the technical field of optical elements, in particular to an optical filter applied to a medical communication sapphire window. The optical filter comprises a substrate, a main film system, a secondary film system and a metal film system, the main film system is located on one side of the substrate, the secondary film system is located on the other side, opposite to the main film system, of the substrate, the metal film system is located on the upper side of the main film system, the secondary film system is located on the other side, opposite to the main film system, of the substrate, and the metal film system is located on the lower side of the main film system. The main film system comprises four high-refractive-index film layers and four low-refractive-index film layers which are sequentially and alternately overlapped from the substrate to the outside according to the structure of the main film system, and the secondary film system comprises four high-refractive-index film layers and four low-refractive-index film layers which are sequentially and alternately overlapped from the substrate to the outside according to the structure of the secondary film system. The metal film system comprises three layers of Ti, Ni and Au metal film layers which are sequentially and alternately overlapped from the main film system to the outside according to the structure of the metal film system, and the optical filter can realize high transmittance and uniform signal intensity within the wavelength range of a communication channel of 1200-1700 nm, so that high communication efficiency is realized.

Description

Technical Field

[0001] This application relates to the technical field of optical components, and particularly to a filter for a sapphire window used in medical communication. Background Art

[0002] The filter for the sapphire window used in medical communication is a precision optical component designed specifically for medical devices and optical communication systems. Its application scenarios cover precise wavelength control in laser surgery, fluorescence signal extraction in biosensing, and signal demultiplexing in wavelength division multiplexing optical communication systems. The core function is to efficiently screen and modulate specific wavelength optical signals by precisely regulating the optical wave transmission characteristics. This filter uses sapphire (Al2O3 single crystal) as the substrate, taking advantage of its high hardness, wide light transmission range, excellent chemical stability, and biocompatibility to meet the stringent requirements of the medical environment for material reliability. Its film layer usually adopts a multi-layer dielectric film system. Through nanoscale thickness control and interference effects, a balance between high transmittance and a steep cut-off edge is achieved in a wide wavelength range. For example, in an endoscope system, it can transmit visible light tissue reflection signals and filter out excitation light interference, and in optical communication, it is used to separate different wavelength signals (such as 1310nm and 1550nm).

[0003] This filter needs to meet both high power tolerance and environmental stability, which poses challenges to the bonding strength at the film layer - substrate interface. Under complex environmental conditions, the film layer of traditional filters is prone to problems such as peeling and cracking, resulting in a decline in optical performance and seriously affecting the communication quality and the reliability of medical devices. In addition, in a communication system, the transmittance of traditional filters for the communication channel wavelengths in the range of 1200 - 1700nm is not good. The transmittance difference for different wavelengths is large and the overall transmittance is low, making it difficult to meet the requirements of modern high-speed and large-capacity communication for efficient signal transmission.

[0004] Specifically, in the 1200 - 1700nm wavelength band, traditional filters may only have high transmittance at a few specific wavelengths, while the transmittance drops sharply at other wavelengths, forming multiple peaks and valleys. This non-uniform transmittance characteristic causes serious distortion and attenuation of communication signals during transmission. Especially in a wavelength division multiplexing system, signals of different wavelengths cannot pass through the filter with similar high efficiency, resulting in inconsistent signal intensities in each channel, increasing the difficulty of signal demultiplexing, and reducing the overall performance and stability of the communication system. Summary of the Invention

[0005] To solve the above problems, the present application provides a filter for a sapphire window used in medical communication, aiming to achieve a synergistic improvement in high-power tolerance, environmental stability, and excellent optical performance, ensuring that in complex and variable medical communication scenarios, the optical signal transmission of the 1200 - 1700nm communication channel wavelength can be accurately regulated, effectively suppressing the wave peak and wave valley phenomena, making the signal intensities of each channel highly consistent, significantly reducing the difficulty of signal demultiplexing, and thus comprehensively improving the overall performance and reliability of the communication system, providing a solid guarantee for the high-quality and stable transmission of medical communication.

[0006] The filter for a sapphire window used in medical communication provided by the present application adopts the following technical solutions: A filter for a sapphire window used in medical communication includes a substrate, a main film system, a secondary film system, and a metal film system. The main film system is located on one side of the substrate, the secondary film system is located on the other side of the substrate opposite to the main film system, and the metal film system is located on the upper side of the main film system. The film system structure of the filter for a sapphire window used in medical communication is: M1M2M3LHLH|Sub|(LH) 2 , and the working wavelength range is 1200 - 1700nm; wherein, Sub is the substrate, M1M2M3 is the metal film system, LHLH is the main film system, and (LH) 2 is the secondary film system, H is the TA2O5 film layer, L is the SiO2 film layer, M1 is the Ti film layer, M2 is the Ni film layer, and M3 is the Au film layer; The main film system includes 4 high-refractive-index film layers and low-refractive-index film layers alternately stacked in sequence from the substrate outward according to the main film system structure. The geometric thickness values of the first to fourth layers are: the first layer is 86.45nm, the second layer is 36.37nm, the third layer is 193.22nm, and the fourth layer is 251.12nm; The secondary film system includes 4 high-refractive-index film layers and low-refractive-index film layers alternately stacked in sequence from the substrate outward according to the secondary film system structure. The geometric thickness values of the first to fourth layers are: the first layer is 86.45nm, the second layer is 36.37nm, the third layer is 193.22nm, and the fourth layer is 251.12nm; The metal film system includes 3 layers of Ti, Ni, and Au metal film layers alternately stacked in sequence from the main film system outward according to the metal film system structure. The geometric thickness values of the first to third layers are: the first layer is 50nm, the second layer is 120nm, and the third layer is 530nm.

[0007] Further, the substrate is a sapphire substrate.

[0008] Further, the Ti film layer in the metal film system is deposited on the main film system by physical vapor deposition.

[0009] Further, in the metal film system, the Ni film layer is on the Ti film layer by means of laser micro-area welding.

[0010] Further, the laser source used for the laser micro-area welding is a YAG laser, with a pulse width of 10 ms and a power density of 10 6 W / cm 2 .

[0011] Further, in the metal film system, the Au film layer is plated on the Ni film layer by welding.

[0012] Further, the specific welding method is brazing: using Au-20Sn, heating to above 280 °C in a vacuum or inert atmosphere to achieve the bonding of Au and Ni, controlling the heating rate at 5-10 °C / s, the holding time at 5-10 minutes, and the cooling rate at 3-5 °C / s.

[0013] Further, the average reflectivity of natural light of the filter used for the medical communication sapphire window is less than 0.2% in the wavelength range of 1200-1700 nm.

[0014] In summary, the present application has the following beneficial effects: 1. By optimizing the film system structure and the metal film system design, and combining the high hardness and chemical stability of the sapphire substrate, the present application significantly enhances the anti-peeling and anti-cracking capabilities of the filter in a complex medical communication environment; Ti as a transition layer can relieve thermal mismatch and improve the interfacial bonding force, Ni as an intermediate layer plays a connecting role, and Au can improve the welding ability and effectively prevent penetration during application; in addition, the specific coating processes of each metal film layer enable high-strength bonding between metal layers, effectively coping with the thermal stress caused by high-power lasers and temperature fluctuations. 2. By precisely controlling the thickness of each film layer, the present application uses the interference effect to achieve the balance of high transmittance and steep cut-off edges in a wide wavelength band, effectively suppressing the peak and valley phenomena of traditional filters, making the signal intensity in the communication channel highly consistent, significantly reducing the difficulty of signal demultiplexing in the wavelength division multiplexing system, and improving the communication rate and capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the following described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 It is a schematic structural diagram of the filter used for the medical communication sapphire window in the embodiment of the present application; Figure 2This is the reflectivity-wavelength curve of the filter for the sapphire window used in the embodiments of this application in medical communication. Detailed implementation manners

[0017] To more clearly illustrate the present invention, the present invention will be further described below in conjunction with preferred embodiments and the accompanying drawings. It should be clear that the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0018] Embodiment Referring to the attached Figure 1 and the attached Figure 2 A filter for a sapphire window used in medical communication, with its working wavelength range being 1200 - 1700 nm, includes a substrate, a main film system, and a secondary film system. The main film system is located on one side of the substrate, the secondary film system is located on the other side of the substrate opposite to the main film system, and the metal film system is located on the upper side of the main film system; The main film system includes 4 high-refractive-index film layers and low-refractive-index film layers alternately stacked in sequence from the substrate outward according to the main film system structure. The main film system structure is: substrate / 86.45 nm H, 36.37 nm L, 193.22 nm H, 251.12 nm L / Ti; The secondary film system includes 4 high-refractive-index film layers and low-refractive-index film layers alternately stacked in sequence from the substrate outward according to the secondary film system structure. The secondary film system structure is: substrate / 86.45 nm H, 36.37 nm L, 193.22 nm H, 251.12 nm L / air; The metal film system includes 3 metal film layers alternately stacked in sequence from the main film system outward according to the metal film system structure. The metal film system structure is: L / 50 nm Ti, 120 nm Ni, 530 nm Au / air; Among them, H is a high-refractive-index film layer, L is a low-refractive-index film layer. In this embodiment, H is a TA2O5 film layer, L is a SiO2 film layer, and the substrate is selected as a sapphire substrate, which has the advantages of high hardness, high heat resistance, high transparency in the NIR region, and excellent physical and chemical properties; The main film system and the secondary film system are deposited on the substrate by vacuum coating. Among them, the TA2O5 film layer is deposited by ion beam-assisted deposition for vapor deposition coating. During the evaporation process, an ion beam is introduced to bombard the surface of the film layer to improve the atomic mobility and promote densification; the SiO2 film layer is deposited by reactive ion plating for vapor deposition coating. During the sputtering process, a reactive gas O2 is introduced to make the sputtered Si atoms react with O2 to form SiO2, making the film layer dense and the refractive index precisely controllable.

[0019] In the metal film system, a high-energy electron beam is used to bombard the Ti target, causing it to evaporate and deposit on the surface of the main film system to form a Ti film layer. The specific process parameters are controlled as follows: the vacuum degree is <10 -3 Pa, the evaporation rate is 0.2 nm / s, and the substrate temperature is 165 °C, making it a transition layer, effectively alleviating the thermal mismatch and improving the interfacial bonding strength; Using a YAG laser as the laser source, the pulse width is controlled at 10 ms, and the power density is 10 6 W / cm 2 , and metal Ni is laser micro-region welded on the Ti film layer to form a metal Ni film layer; in the metal model with a sandwich structure, metal Ni serves as an intermediate layer playing a connecting role: On the one hand, Ni and the Ti film layer have good physical and chemical compatibility. Through laser micro-region welding, a high-strength bond at the Ti / Ni interface is achieved, alleviating the thermal mismatch problem caused by the difference in thermal expansion coefficients; and Ni and the Au film layer form a metallurgical bond through brazing. Its face-centered cubic crystal structure matches that of Au, which can promote the wetting of the filler metal and inhibit the generation of brittle phases; On the other hand, the yield strength and elastic modulus of Ni are between those of Ti and Au, which can effectively disperse the thermal stress generated by high-power lasers or temperature fluctuations, avoiding the cracking of the film layer caused by stress concentration; In addition, the high melting point and good thermal conductivity of Ni enable it to withstand the high temperature of YAG laser welding while avoiding overheating damage to the substrate sapphire.

[0020] Metal Au is then welded on the Ni film layer by brazing to form a metal Au film layer. The specific brazing process parameters are as follows: using Au-20Sn, heating in an inert atmosphere to 285 °C to achieve the bonding of Au and Ni, the heating rate is controlled at 6 °C / s, the holding time is 8 minutes, and the cooling rate is 4 °C / s; In this way, the filter used in the medical communication sapphire window of this application example is obtained. The optical properties of the filter used in the medical communication sapphire window after double-sided coating are measured using an ultraviolet-visible-near-infrared spectrophotometer. Its reflectance-wavelength curve refers to Figure 2 , and it can be seen that the average reflectance of natural light in the wavelength range of 1200 - 1700 nm is less than 0.2%, and the signal intensity height basically remains the same in this communication channel wavelength range, significantly reducing the difficulty of signal demultiplexing in the wavelength division multiplexing system and improving the communication rate and stability.

[0021] The above are all modifications or solutions that are obvious technical inspirations made by those skilled in the art after reading this specification as needed, but as long as they are within the scope of the claims of this application, they should be protected by the patent law.

Claims

1. A filter for a sapphire window used in medical communication, comprising a substrate, a main film system, a secondary film system and a metal film system. The main film system is located on one side of the substrate, the secondary film system is located on the other side of the substrate opposite to the main film system, and the metal film system is located on the upper side of the main film system, characterized in that, The film system structure of the filter applied to the sapphire window for medical communication is: M1M2M3LHLH|Sub|(LH) 2 , and the working wavelength range is 1200 - 1700 nm; Among them, Sub is the substrate, M1M2M3 is the metal film system, LHLH is the main film system, and (LH) 2 is the secondary film system, H is the TA2O5 film layer, L is the SiO2 film layer, M1 is the Ti film layer, M2 is the Ni film layer, and M3 is the Au film layer; The main film system includes 4 high-refractive-index film layers and low-refractive-index film layers that are alternately stacked in sequence from the substrate outward according to the main film system structure. The geometric thickness values of the first to fourth layers are: the first layer is 86.45 nm, the second layer is 36.37 nm, the third layer is 193.22 nm, and the fourth layer is 251.12 nm; The secondary film system includes 4 high-refractive-index film layers and low-refractive-index film layers that are alternately stacked in sequence from the substrate outward according to the secondary film system structure. The geometric thickness values of the first to fourth layers are: the first layer is 86.45 nm, the second layer is 36.37 nm, the third layer is 193.22 nm, and the fourth layer is 251.12 nm; The metal film system includes 3 Ti, Ni, and Au metal film layers that are alternately stacked in sequence from the main film system outward according to the metal film system structure. The geometric thickness values of the first to third layers are: the first layer is 50 nm, the second layer is 120 nm, and the third layer is 530 nm.

2. The filter for a sapphire window used in medical communication according to claim 1, wherein In the metal film system, the Ti film layer is plated on the main film system by physical vapor deposition.

3. The optical filter applied to the sapphire window for medical communication according to claim 1, characterized in that In the metal film system, the Ni film layer is formed on the Ti film layer by laser micro-area welding.

4. The optical filter applied to the sapphire window for medical communication according to claim 3, wherein, The laser source used for the laser micro-area welding is a YAG laser, with a pulse width of 10 ms and a power density of 10 6 W / cm 2 .

5. The optical filter applied to the sapphire window for medical communication according to claim 1, wherein In the metal film system, the Au film layer is plated on the Ni film layer by welding.

6. The optical filter applied to the sapphire window for medical communication according to claim 5, characterized in that, The specific welding method is brazing: using Au-20Sn, heating to above 280 °C in a vacuum or inert atmosphere to achieve the bonding of Au and Ni. The heating rate is controlled at 5-10 °C / s, the holding time is 5-10 minutes, and the cooling rate is 3-5 °C / s.

7. The optical filter applied to the sapphire window for medical communication according to claim 1, wherein The average reflectance of natural light of the filter applied to the medical communication sapphire window in the wavelength range of 1200-1700 nm is less than 0.2%.

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