A lens shading film, a preparation method and application thereof

Abstract

The application belongs to the technical field of endoscope lens coating, and particularly relates to a lens light shielding film, a preparation method and application thereof. The lens light shielding film provided by the application comprises a light absorbing layer, a reflecting layer and an insulating layer which are sequentially stacked, the light absorbing layer is in contact with the lens base body, the material of the light absorbing layer comprises chromium and / or titanium, the material of the reflecting layer comprises aluminum and / or silver, and the material of the insulating layer comprises silicon dioxide and / or silicon nitride. Through the synergistic effect of the light absorbing layer and the reflecting layer, the light shielding performance of the light shielding film is significantly improved. Meanwhile, the lens light shielding film provided by the application is good in uniformity, so that the optical performance of the lens is not affected. In conclusion, the lens light shielding film provided by the application is dense and uniform, can reach OD2 or more, and has a light shielding effect of less than 0.5% in the average transmittance in the visible light range.

Description

Technical Field

[0001] This invention belongs to the field of endoscope lens coating technology, specifically relating to a lens light-shielding film, its preparation method, and its application. Background Technology

[0002] With the rapid development of medicine and the increasing demands for medical applications, the surface shading film of endoscope lenses, as a key component of medical devices, is fundamental to their high-quality imaging. The main function of the shading film is to reduce reflections and glare in high-brightness environments, thereby improving image contrast and clarity. The quality of the shading film is crucial to the overall quality of the endoscope lens.

[0003] Currently, the most common surface treatment method for shading endoscope lenses is ink spraying. However, the shading performance is still relatively poor. Summary of the Invention

[0004] The purpose of this invention is to provide a lens shading film and its preparation method. The lens shading film provided by this invention can significantly improve the light-shielding performance of endoscope lenses.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] The present invention provides a lens light-shielding film, comprising a light-absorbing layer, a reflective layer and an insulating layer stacked sequentially, wherein the light-absorbing layer is in contact with the endoscope lens substrate; the material of the light-absorbing layer includes chromium and / or titanium; the material of the reflective layer includes aluminum and / or silver; and the material of the insulating layer includes silicon dioxide and / or silicon nitride.

[0007] Preferably, the thickness of the light-absorbing layer is 5–15 μm.

[0008] Preferably, the thickness of the reflective layer is 3–15 μm.

[0009] Preferably, the thickness of the insulating layer is 2 to 10 μm.

[0010] Preferably, the thickness of the lens shading film is 10–40 μm.

[0011] This invention provides a method for preparing the lens shading film described in the above technical solution, comprising the following steps:

[0012] A light-absorbing layer, a reflective layer, and an insulating layer are sequentially deposited on the side of the lens using a vapor deposition method to obtain the lens light-shielding film on the side of the lens.

[0013] Preferably, the conditions for the vapor deposition include: a vacuum value of 1.0 × 10⁻⁶. -4 ~1.3×10 -3Pa; the endoscope lens rotates at a speed of 25–80 rpm; the purity of the target material used for vapor deposition is >99.99%.

[0014] Preferably, the vapor deposition includes magnetron sputtering or electron beam vacuum evaporation;

[0015] The magnetron sputtering conditions include: a power of 1-12 kW for depositing the light-absorbing layer and a time of 30-60 min; a power of 3-12 kW for depositing the reflective layer and a time of 20-70 min; a power of 3-14 kW for depositing the insulating layer and a time of 5-30 min; and a flow rate of 50-120 sccm for the reactive gas.

[0016] The conditions for electron beam vacuum evaporation include: a current of 200–800 mA for depositing the light-absorbing layer and a time of 15–45 min; a current of 200–1000 mA for depositing the reflective layer and a time of 30–60 min; a current of 100–500 mA for depositing the insulating layer and a time of 10–50 min; and a flow rate of 30–100 sccm for the reaction gas.

[0017] Preferably, before depositing the light-absorbing layer, the method further includes: performing plasma cleaning on the endoscope lens, wherein the gas used for plasma cleaning includes an inert gas, wherein the inert gas includes argon and / or helium, and the purity of the argon or helium is >99.99%; the flow rate of the inert gas is 10-90 sccm;

[0018] After the insulating layer deposition is completed, the process further includes: cooling the deposited sample to obtain the lens light-shielding film; the cooling time is 10 to 60 minutes.

[0019] This invention provides the application of the lens shading film described in the above technical solution or the lens shading film prepared by the preparation method described in the above technical solution in the lens shading film of endoscopes.

[0020] This invention provides a lens hood, comprising a light-absorbing layer, a reflective layer, and an insulating layer stacked sequentially, wherein the light-absorbing layer is in contact with the lens substrate; the material of the light-absorbing layer includes chromium and / or titanium; the material of the reflective layer includes aluminum and / or silver; and the material of the insulating layer includes silicon dioxide and / or silicon nitride. This invention significantly improves the light-blocking performance of the hood through the synergistic effect of the light-absorbing and reflective layers; simultaneously, the lens hood provided by this invention has good uniformity, thereby ensuring that the optical performance of the lens is not affected; this invention provides a reflective layer on the surface of the light-absorbing layer (the outer surface, the surface away from the lens head substrate), the main function of which is to reflect light and reduce the amount of light entering the lens; since the reflective layer is on the outer surface of the light-absorbing layer, it also protects the light-absorbing layer; in addition, the special physical properties of the reflective layer (aluminum or silver) allow it to exhibit corrosion resistance even when the insulating layer is damaged. This invention provides an insulating layer on the surface of the reflective layer (outer surface, away from the head base). This insulating layer serves as a protective layer for the light-absorbing and reflective layers, protecting the endoscope lens (i.e., the lens substrate), the light-absorbing layer, and the reflective layer from scratches, abrasion, and chemical corrosion, thus extending their service life. Simultaneously, the insulating layer provides excellent insulation between the lens and the circuitry or housing, preventing electrical breakdown and improving product safety. Furthermore, the insulating layer exhibits good stability, allowing the lens to be used under harsh conditions such as high temperatures. In summary, the lens light-shielding film coating provided by this invention is dense and uniform, achieving an OD2 or higher, with an average transmittance of less than 0.5% in the visible light range. Moreover, the lens light-shielding film possesses excellent abrasion and corrosion resistance, resulting in a long service life.

[0021] This invention provides a method for preparing the lens shading film described in the above-mentioned technical solution, comprising the following steps: using physical vapor deposition (PVD), a light-absorbing layer, a reflective layer, and an insulating layer are sequentially deposited on the side of the lens to obtain the lens shading film. This invention utilizes PVD, enabling multi-angle coating on the side of the endoscope lens, thereby achieving uniform film formation on the side of the endoscope lens, improving the overall uniformity of the lens shading film, and ensuring that the optical performance of the lens is not affected. This invention employs PVD, which has simple operation steps and can simultaneously produce batches of products, accelerating the preparation speed of the lens shading film and solving the problem of low production efficiency.

[0022] This invention provides the application of the lens shading film described in the above-described technical solution, or the lens shading film prepared by the above-described technical solution, in endoscope lens shading films. The lens shading film provided by this invention has a wide range of applications and is suitable for various types of lenses, such as endoscope lenses. Attached Figure Description

[0023] Figure 1A macroscopic diagram showing the comparison before and after fabrication of the light-shielding film for the endoscope lens provided in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the film structure of the lens shading film;

[0025] Figure 3 The transmittance curves of the endoscope lens light-shielding film prepared in Examples 1 and 2 of the present invention;

[0026] In the diagram: 1 is the light-absorbing layer, 2 is the reflective layer, 3 is the insulating layer, and 4 is the metal layer. Detailed Implementation

[0027] The present invention provides a lens light-shielding film, comprising a light-absorbing layer, a reflective layer and an insulating layer stacked sequentially, wherein the light-absorbing layer is in contact with the lens substrate; the material of the light-absorbing layer includes chromium and / or titanium; the material of the reflective layer includes aluminum and / or silver; and the material of the insulating layer includes silicon dioxide and / or silicon nitride.

[0028] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.

[0029] Figure 2 This is a schematic diagram of the lens shading film provided by the present invention. The following is in conjunction with... Figure 2 The lens shading film provided by the present invention will be described in detail.

[0030] The lens shading film provided by this invention includes a light-absorbing layer 1. In this invention, the light-absorbing layer 1 is in contact with the lens substrate. One surface of the light-absorbing layer 1 is in contact with the lens substrate. The material of the light-absorbing layer 1 includes chromium and / or titanium, and in this embodiment, it can be chromium. In this invention, metallic chromium (Cr) has light-absorbing properties, mainly absorbing visible light and ultraviolet light, which can reduce light reflection and transmission, and it is not oxidized at room temperature and has stable chemical properties. In this invention, the thickness of the light-absorbing layer is preferably 5-15 μm, and in this embodiment, it can be 15 μm. The function of the light-absorbing layer 1 is to absorb visible light and ultraviolet light, thereby reducing light reflection and transmission.

[0031] The lens shading film provided by this invention includes a reflective layer 2 disposed on the other surface of the light-absorbing layer 1. In this invention, the reflective layer 2 is an intermediate layer, one surface of the reflective layer 2 is in contact with the light-absorbing layer 1, and the other surface of the reflective layer 2 is in contact with the insulating layer 3. The material of the reflective layer 2 includes aluminum and / or silver, and in this embodiment, it can be aluminum. In this invention, metallic aluminum (Al) has high reflectivity in the ultraviolet, visible, and infrared light bands, which can further reflect some of the light transmitted through the light-absorbing layer 1, and it has good chemical stability. In this invention, the thickness of the reflective layer is preferably 3 to 15 μm, and in this embodiment, it can be 10 μm or 15 μm. In this invention, the main function of the reflective layer is to reflect light and reduce the amount of light entering the lens; since the reflective layer is on the outer surface of the light-absorbing layer, it also has the function of protecting the light-absorbing layer; in addition, the special physical properties of the reflective layer (aluminum or silver) can demonstrate its corrosion resistance in the special case of damage to the insulating layer.

[0032] The lens light-shielding film provided by this invention includes an insulating layer 3 disposed on the surface of the reflective layer 2. In this invention, the material of the insulating layer 3 includes silicon dioxide and / or silicon nitride, and in the embodiments, it can be silicon dioxide. In this invention, the silicon dioxide has extremely high chemical stability and insulation properties. In this invention, the thickness of the insulating layer 3 is 2–10 μm, and in the embodiments, it can be 5 μm. In this invention, the insulating layer 3 serves as a protective layer, protecting the endoscope lens, light-absorbing layer, and reflective layer from scratches, abrasion, and chemical corrosion, thus extending its service life; the insulating layer 3 also provides good insulation between the lens and the circuitry or housing, preventing electrical breakdown and improving product safety; furthermore, the good stability of the insulating layer 3 allows the lens to be used under harsh conditions such as high temperatures.

[0033] In this invention, the thickness of the lens light-shielding film is preferably 10-40 μm, and in the embodiments it can be 30 μm or 35 μm. The light-absorbing layer 1 and the reflective layer 2 in the lens light-shielding film are collectively referred to as the metal layer 4. The lens light-shielding film coating provided by this invention is dense and uniform, achieving an OD2 of over, and has a light-shielding effect with an average transmittance of less than 0.5% in the visible light range.

[0034] This invention provides a method for preparing the lens shading film described in the above technical solution, comprising the following steps:

[0035] A light-absorbing layer, a reflective layer, and an insulating layer are sequentially deposited on the side of the lens using a physical vapor deposition method to obtain the lens light-shielding film on the side of the lens.

[0036] This invention employs physical vapor deposition (PVD) to prepare lens shading films, enabling multi-angle coating of endoscope lenses to achieve uniform film formation on their surface, resulting in a dense and uniform lens shading film. In this invention, the preferred implementation steps of the physical vapor deposition include:

[0037] Step 1: Inside the vacuum chamber, cover both ends of the endoscope lens and fix it on the fixture. Place it on the rotating workpiece in the vacuum chamber. Install the target material for the light-absorbing layer, the target material for the reflective layer, and the target material for the insulating layer on the vacuum coating equipment respectively. Then, evacuate the vacuum chamber of the coating equipment until the set vacuum level is reached.

[0038] Step 2: A physical vapor deposition method is used to deposit a film on the sides of the endoscope lens. The fixture rotates at a constant speed on a rotary table. In the first stage, an inert gas is introduced for plasma cleaning to obtain a clean endoscope lens. In the second stage, a light-absorbing layer is deposited on the four sides of the endoscope lens. In the third stage, a reflective layer is deposited on the four sides of the endoscope lens. In the fourth stage, an insulating layer is deposited on the four sides of the endoscope lens to obtain an endoscope lens with a light-shielding film deposited on all four sides.

[0039] Step 3: After the sample prepared in Step 2 has cooled with the equipment, open the vacuum chamber to obtain the lens shading film.

[0040] In this invention, the vacuum value obtained in step one is preferably 1.0 × 10⁻⁶. -4 ~1.3×10 -3 Pa, specifically 1.0 × 10 in the embodiment. -3 Pa or 1.0 × 10 -4 Pa.

[0041] In this invention, prior to depositing the light-absorbing layer, the invention preferably further includes: performing plasma cleaning on the endoscope lens. In this invention, the gas used for plasma cleaning preferably includes an inert gas, which preferably includes argon and / or helium; in the embodiments, argon may be used. The purity of the argon or helium is preferably >99.99%; the flow rate of the inert gas is preferably 10–90 sccm, specifically 90 sccm or 10 sccm in the embodiments. In this invention, the gas used for plasma cleaning preferably also includes oxygen; when the gas used for plasma cleaning also includes oxygen, the flow rate of the oxygen is preferably 10–60 sccm, specifically 60 sccm in the embodiments.

[0042] In this invention, the physical vapor deposition conditions preferably include: a vacuum value of 1.0 × 10⁻⁶. -4 ~1.3×10 - 3 Pa, specifically 1.0 × 10 in the embodiment.-3 Pa or 1.0 × 10 -4 Pa. The endoscope lens rotates, preferably at a speed of 25–80 rpm, and in this embodiment, at 80 rpm or 30 rpm. The purity of the target material used for physical vapor deposition is preferably >99.99%.

[0043] In this invention, the physical vapor deposition preferably includes magnetron sputtering or electron beam vacuum evaporation.

[0044] In this invention, the preferred conditions for magnetron sputtering include: a power of 1-12 kW for depositing the light-absorbing layer (6 kW in an example), and a time of 30-60 min (40 min in an example); a power of 3-12 kW for depositing the reflective layer (5 kW in an example), and a time of 20-70 min (30 min in an example); a power of 3-14 kW for depositing the insulating layer (5 kW in an example), and a time of 5-30 min (10 min in an example); the preferred reaction gas for depositing the insulating layer is oxygen, and the preferred flow rate of the reaction gas is 50-120 sccm (80 sccm in an example). In this invention, when preparing the lens light-shielding film using magnetron sputtering, the gas used for plasma cleaning is an inert gas, and the preferred conditions for plasma cleaning include: a flow rate of inert gas of more preferably 50-90 sccm (90 sccm in an example), and an ICP power of 0.1-0.8 kW (0.6 kW in an example).

[0045] In this invention, the preferred conditions for electron beam vacuum evaporation include: a current for depositing the light-absorbing layer is preferably 200–800 mA, 500 mA in an example; a time is preferably 15–45 min, 30 min in an example; a current for depositing the reflective layer is preferably 200–1000 mA, 400 mA in an example; a time is preferably 30–60 min, 45 min in an example; a current for depositing the insulating layer is preferably 100–500 mA, 200 mA in an example; a time is preferably 10–50 min, 20 min in an example; the preferred reaction gas for depositing the insulating layer is oxygen; and the preferred flow rate of the reaction gas is 30–100 sccm, 80 sccm in an example. In this invention, when preparing the lens light-shielding film using electron beam vacuum evaporation, the gases used for plasma cleaning are an inert gas and oxygen. The preferred conditions for plasma cleaning include: a flow rate of the inert gas is more preferably 10–20 sccm, 10 sccm in an example. The oxygen flow rate is preferably 10 to 60 sccm, and in the embodiment it can be 60 sccm.

[0046] In this invention, after the insulating layer deposition is completed, the invention preferably further includes: cooling the deposited sample to obtain the lens shading film; the cooling time is preferably 10-60 minutes. By controlling the cooling time, this invention can better ensure the obtaining of a high-performance lens shading film product.

[0047] This invention employs physical vapor deposition to accelerate the preparation speed of lens shading film and solves the problem of low production efficiency. At the same time, it uses multi-angle deposition of film layers to achieve uniform film formation on the surface of the lens shading film, ensuring that the optical performance of the lens is not affected.

[0048] This invention provides the application of the lens shading film described in the above technical solution or the lens shading film prepared by the preparation method described in the above technical solution in the lens shading film of endoscopes.

[0049] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0050] Figure 1 This is a macroscopic diagram showing the comparison before and after the preparation of the light-shielding film for the endoscope lens in Embodiments 1-2 of the present invention.

[0051] Example 1

[0052] This embodiment provides a method for preparing a light-shielding film for an endoscope lens. This embodiment uses a vacuum coating method to deposit a light-shielding film with a total thickness of 30 μm on the surface of the endoscope lens by magnetron sputtering. The thickness of the chromium (Cr) light-absorbing layer is 15 μm; the thickness of the aluminum (Al) reflective layer is 10 μm; and the thickness of the silicon dioxide insulating layer is 5 μm.

[0053] Magnetron sputtering specifically includes the following steps:

[0054] Inside the vacuum chamber, the endoscope lens is covered at both ends and fixed to a fixture, then placed on a rotating workpiece within the vacuum chamber. The light-absorbing target (chromium, purity > 99.99%), the reflective target (Al, purity > 99.99%), and the insulating target (Si, purity > 99.99%) are respectively mounted on the vacuum coating equipment. The vacuum chamber of the coating equipment is then evacuated until the set vacuum level of 1.0 × 10⁻⁶ is reached. -3 Pa;

[0055] Magnetron sputtering was used to deposit films on the four sides of an endoscope lens. The fixture rotated uniformly on a rotary table at a speed of 80 rpm. In the first stage, an inert gas (argon) was introduced at a flow rate of 90 sccm, and the ICP power was 0.6 kW for plasma cleaning, resulting in a clean endoscope lens. In the second stage, a light-absorbing layer was deposited on the four sides of the endoscope lens. In the third stage, a reflective layer was deposited on the four sides of the endoscope lens. In the fourth stage, an insulating layer was deposited on the four sides of the endoscope lens, resulting in an endoscope lens with light-shielding films deposited on all four sides. The conditions for magnetron sputtering deposition of the light-shielding film included: vacuum level: 1.0 × 10⁻⁶. -3 Pa; Chromium (Cr) light-absorbing layer power 6kW, time 40min; Aluminum (Al) reflective layer power 5kW, time 30min; Silica insulating layer power 5kW, time 10min; The reaction gas for depositing the silica insulating layer is oxygen, and the flow rate of oxygen introduced for the reaction is 80sccm.

[0056] After the prepared endoscope lens light-shielding film is cooled with the equipment for 30 minutes, the vacuum chamber is opened to obtain the endoscope lens light-shielding film.

[0057] After testing, the test results are as follows: Figure 3 As shown, the endoscope lens shading film prepared in this embodiment has a good shading effect while maintaining its optical performance.

[0058] Example 2

[0059] This embodiment provides a method for preparing a light-shielding film for an endoscope lens. This embodiment uses a vacuum coating method to deposit a light-shielding film with a total thickness of 35 μm on the surface of the endoscope lens by electron beam vacuum evaporation coating. The thickness of the chromium (Cr) light-absorbing layer is 15 μm; the thickness of the aluminum (Al) reflective layer is 15 μm; and the thickness of the silicon dioxide insulating layer is 5 μm.

[0060] Electron beam vacuum evaporation coating specifically includes the following steps:

[0061] Inside the vacuum chamber, the endoscope lens is covered at both ends and fixed to a fixture, then placed on a rotating workpiece within the vacuum chamber. The light-absorbing target (chromium, purity > 99.99%), the reflective target (Al, purity > 99.99%), and the insulating target (Si, purity > 99.99%) are respectively mounted on the vacuum coating equipment. The vacuum chamber of the coating equipment is then evacuated until the set vacuum level of 1.0 × 10⁻⁶ is reached. -4 Pa;

[0062] Electron beam vacuum evaporation deposition was used to deposit films on the four sides of an endoscope lens. The fixture rotated uniformly on a rotary table at a speed of 30 rpm. In the first stage, an inert gas (argon) was introduced at a flow rate of 10 sccm, and oxygen at 60 sccm for plasma cleaning, resulting in a clean endoscope lens. In the second stage, a light-absorbing layer was deposited on the four sides of the endoscope lens. In the third stage, a reflective layer was deposited on the four sides of the endoscope lens. In the fourth stage, an insulating layer was deposited on the four sides of the endoscope lens, resulting in an endoscope lens with a light-shielding film deposited on all four sides. The conditions for preparing the light-shielding film using electron beam vacuum evaporation deposition included: vacuum level: 1.0 × 10⁻⁶. -4 Pa; Chromium (Cr) light-absorbing layer current 500mA, time 30min; Aluminum (Al) reflective layer current 400mA, time 45min; Silica insulating layer current 200mA, time 20min; The reaction gas for depositing the silica insulating layer is oxygen, and the flow rate of oxygen introduced for the reaction is 80sccm.

[0063] After the prepared endoscope lens light-shielding film is cooled with the equipment for 30 minutes, the vacuum chamber is opened to obtain the endoscope lens light-shielding film.

[0064] After testing, the test results are as follows: Figure 3 As shown, the endoscope lens light-shielding film prepared in this embodiment has excellent light-shielding effect while maintaining its optical performance.

[0065] In this invention, the films prepared in Examples 1 and 2 were prepared using two different processes: magnetron sputtering and electron beam evaporation. The resulting film structures and thicknesses differed, leading to variations in transmittance. However, transmittance values ​​below 0.1% are very small. While there are some differences in transmittance between Examples 1 and 2 when magnified along the Y-axis, the overall difference is negligible below 0.1%.

[0066] As can be seen from the above embodiments, the present invention has the following advantages compared with the prior art:

[0067] The lens shading film prepared by this invention has a good shading effect: This invention significantly improves the shading performance of the lens through the synergistic effect of the light-absorbing layer and the reflective layer.

[0068] The lens shading film prepared by this invention is highly durable: the reflective layer effectively protects the light-absorbing layer, improves the film's abrasion and corrosion resistance, and extends its service life.

[0069] The lens shading film prepared by this invention has a wide range of applications and is suitable for various types of lenses, such as endoscope lenses.

[0070] This invention employs physical vapor deposition to deposit film layers from multiple angles and precisely control the film thickness, achieving uniform film formation on the lens surface, improving the uniformity of the lens shading film, ensuring that the optical performance of the lens is not affected, and enabling the simultaneous production of large quantities of products with high production efficiency.

[0071] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. Use of a lens hood in an endoscope lens hood, characterized in that, The lens light shielding film comprises a light-absorbing layer, a reflecting layer and an insulating layer which are sequentially stacked, the light-absorbing layer is in contact with the lens base body, the material of the light-absorbing layer comprises chromium and / or titanium, the material of the reflecting layer comprises aluminum and / or silver, and the material of the insulating layer comprises silicon dioxide and / or silicon nitride. The preparation method of the lens light shielding film comprises the following steps: The light-absorbing layer, the reflecting layer and the insulating layer are sequentially deposited on the side of the lens by physical vapor deposition, and the lens light shielding film is obtained on the side of the lens.

2. Use according to claim 1, characterized in that, The thickness of the light-absorbing layer is 5-15 μm.

3. Use according to claim 1, characterized in that, The thickness of the reflecting layer is 3-15 μm.

4. Use according to claim 1, characterized in that, The thickness of the insulating layer is 2-10 μm.

5. The use according to any one of claims 1 to 4, characterized in that, The thickness of the lens light shielding film is 10-40 μm.

6. Use according to claim 1, characterized in that, The conditions of the physical vapor deposition include: vacuum value is 1.0x10 -4 -1.3x10 -3 Pa; the endoscope lens rotates, the speed of the rotation is 25-80 rpm; the purity of the target material used in the physical vapor deposition is >99.99%.

7. Use according to claim 1 or 6, characterized in that, The physical vapor deposition comprises magnetron sputtering or electron beam vacuum evaporation. The conditions of the magnetron sputtering comprise: the power for depositing the light-absorbing layer is 1-12 kW, the time is 30-60 min; the power for depositing the reflecting layer is 3-12 kW, the time is 20-70 min; the power for depositing the insulating layer is 3-14 kW, the time is 5-30 min, and the flow rate of the reaction gas is 50-120 sccm. The conditions of the electron beam vacuum evaporation comprise: the current for depositing the light-absorbing layer is 200-800 mA, the time is 15-45 min; the current for depositing the reflecting layer is 200-1000 mA, the time is 30-60 min; the current for depositing the insulating layer is 100-500 mA, the time is 10-50 min, and the flow rate of the reaction gas is 30-100 sccm.

8. The use according to claim 1, characterized in that, Before depositing the light-absorbing layer, the endoscope lens is subjected to plasma cleaning, the gas used in the plasma cleaning comprises an inert gas, the inert gas comprises argon and / or helium, the purity of the argon and the helium is >99.99%, and the flow rate of the inert gas is 10-90 sccm. After the deposition of the insulating layer is completed, the sample obtained by deposition is cooled to obtain the lens light shielding film, and the cooling time is 10-60 min.

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