Medical device comprising optical element with anti-reflective coating

Abstract

A medical device comprises an optical element (10) having a substrate (12) and an anti-reflection coating (14) applied to a coating surface (13) of the substrate (12), the anti-reflection coating (14) comprising an alternating layer sequence of sub-layers (18, 20) having different refractive indices. In addition to the alternating sequence of layers, the anti-reflection coating (14) comprises an anti-corrosion layer (22) which is the farthest layer of the anti-reflection coating (14) from the coating layer (13) of the substrate (12). The anti-corrosion layer (22) is designed such that the ratio of the refractive index of the anti-corrosion layer (22) to the layer thickness of the anti-corrosion layer (22) in nanometer ranges from 0.3 to 0.9. The utility model further relates to the use of an optical element (10) in a medical device.

Description

Technical Field

[0001] This utility model relates to a medical device, the medical device comprising an optical element having a substrate and an anti-reflective coating applied to a coated surface of the substrate, and to the use of an optical element. Background Technology

[0002] Antireflective coatings are used to improve the transmission of light falling onto an optically transparent substrate and / or at least reduce the degree of interference from optical effects. A problem arises here: as the outermost component of the corresponding optical element comprising the substrate and the antireflective coating, the antireflective coating is exposed to environmental influences that may impair its functionality. In antireflective coatings, this effect is further enhanced by the fact that the outermost sublayer of the antireflective coating, i.e., the layer to which incident electromagnetic radiation reaches, should be made of a material with the lowest possible refractive index to achieve the highest possible transmittance. However, such a material is particularly sensitive to damage.

[0003] It is known that antireflective coatings are protected against mechanical loads and the resulting damage, such as scratches. For this purpose, a material with a high refractive index is applied as the outermost sublayer of the antireflective coating, because such materials typically have increased resistance to mechanical loads.

[0004] For example, DE 10 2018 116 993 B4 describes an optical component having a stack of layers having at least three types of successive layers, each layer having a different refractive index. The uppermost layer has a lower refractive index compared to the second uppermost layer, but a higher refractive index compared to another layer disposed below the uppermost and second uppermost layers.

[0005] US 2018 / 0081085 A1 describes an electronic device, such as a mobile phone, computer, and watch, comprising a transparent element, such as a display or camera window. The transparent element has an anti-reflective coating having an alternating sequence of dielectric layers with high and low refractive indices. To improve the scratch resistance of the anti-reflective coating, an outermost interference filtering layer made of a high-refractive-index material can be applied to the anti-reflective coating.

[0006] WO 2022 / 125846 A1 discloses a cover glass for electronic devices such as mobile devices, tablets, and automotive displays, the cover glass having an outer optical film structure and an inner optical film structure, each comprising a plurality of alternating sublayers having high and low refractive indices. The high-refractive-index sublayers of the outer optical film structure comprise nitrides or oxynitrides, and the high-refractive-index sublayers of the inner optical film structure comprise oxides or nitrides. An anti-scratch layer made of a high-refractive-index material may also be applied to the outer optical film structure.

[0007] However, depending on the application, this is insufficient to ensure resistance to mechanical loads. More precisely, it may be necessary to additionally provide resistance to chemicals. Especially in the case of optical components used in medical devices, regular cleaning with chemically abrasive solutions, such as strongly alkaline solutions, is necessary. This effect is further amplified by the fact that common cleaning processes must be performed in autoclaves, thereby additionally generating high pressure and temperature loads. Summary of the Invention

[0008] Therefore, the purpose of this invention is to provide an optical element with an anti-reflective coating for use in medical devices, the optical element being resistant to chemicals, such as alkaline solutions, and simultaneously having high transmittance or low reflectance, and to provide a medical device having such an optical element.

[0009] The objective is achieved by the medical device according to the present invention. Advantageous embodiments are described in examples that can be arbitrarily combined with each other.

[0010] The medical device according to this invention includes an optical element having a substrate and an anti-reflective coating applied to a coated surface of the substrate, wherein the anti-reflective coating comprises an alternating sequence of layers consisting of sublayers with different refractive indices. In addition to the alternating layer sequence, the anti-reflective coating includes an anti-corrosion layer, which is the layer of the anti-reflective coating furthest from the coated surface of the substrate. The anti-corrosion layer is designed such that the ratio of the refractive index of the anti-corrosion layer to its thickness in nanometers is in the range of 0.3 to 0.9.

[0011] This invention is based on the following fundamental concept: an anti-corrosion layer is additionally provided on an alternating sequence of layers required for the desired optical transmittance, wherein the refractive index and thickness of the anti-corrosion layer are specifically coordinated with each other. It is feasible in this manner to use a high-refractive-index material in the anti-corrosion layer, which has high chemical resistance without excessively impairing the transmittance through the anti-reflective coating. However, at the same time, the anti-corrosion layer has a certain thickness so that it does not completely degrade after multiple cleaning processes, thereby improving the service life of the anti-reflective coating and optical components.

[0012] In this sense, the anti-corrosion layer functions as a "capping" layer for the anti-reflective coating.

[0013] According to this invention, when calculating the ratio of the refractive index to the thickness of the anti-corrosion layer, the layer thickness is measured in nanometers. However, to calculate the ratio, the corresponding value of the layer thickness is used dimensionlessly, making the ratio dimensionless in the range of 0.3 to 0.9. For example, the refractive index n... k The value is 2.0 and the layer thickness d k The 3.2nm anti-corrosion layer has α=n k / d k =2.0 / 3.2 is a ratio of 0.625.

[0014] The refractive index is the refractive index as measured at a measurement temperature of 20°C and a wavelength of 550 nm.

[0015] The anti-corrosion layer is made of a high refractive index material selected from the group consisting of zirconium oxide, hafnium oxide and mixed oxides thereof.

[0016] Preferably, the high refractive index material is zirconium oxide or hafnium oxide, and particularly preferably zirconium oxide.

[0017] The suitability of high-refractive-index materials as anti-corrosion layers is crucial, particularly in terms of resistance to chemicals, especially alkaline solutions. It has been recognized that zirconium oxide, hafnium oxide, and their mixed oxides are suitable in this regard, thereby enabling the creation of particularly resistant anti-corrosion layers. Furthermore, by coordinating the refractive index and layer thickness of the anti-corrosion layer according to this invention, excellent optical properties of the anti-reflective coating can also be achieved.

[0018] It has also been found that some materials commonly used to protect antireflective coatings from mechanical damage, such as scratches, do not have sufficient resistance to chemicals. In this sense, in particular, alumina (Al2O3), silicon nitride (Si3N4), niobium oxide (Nb2O5), and titanium oxide (TiO2) are unsuitable as materials for the anti-corrosion layer of the optical elements according to this invention.

[0019] Due to its hardness, the so-called "diamond-like carbon" (abbreviated as "DLC") used in anti-scratch layers is not intended to be used as a material for anti-corrosion layers according to this invention.

[0020] The anti-corrosion layer can have a refractive index in the range of 1.8 to 2.5, preferably in the range of 1.9 to 2.2. If the refractive index of the anti-corrosion layer is higher than 2.5, the transmittance of the anti-reflective coating will be reduced too much, or the anti-corrosion layer must be designed to be very thin, making it impossible to guarantee sufficient chemical resistance or corrosion resistance.

[0021] Furthermore, the anti-corrosion layer can have a thickness in the range of 3.0 nm to 6.0 nm, preferably in the range of 3.0 nm to 5.0 nm. With a layer thickness below 3.0 nm, the resistance and service life of the anti-corrosion layer are excessively limited or shortened. With a layer thickness greater than 6.0 nm, the transmittance of the anti-reflective coating is excessively reduced.

[0022] To further enhance the corrosion resistance of the anti-corrosion layer, it can be applied by sputtering, particularly by direct current (DC) sputtering, radio frequency (HF) sputtering, magnetron sputtering, or ion beam sputtering. It has been found that sputtering methods produce particularly resistant or robust anti-corrosion layers, especially compared to coating methods in which the corresponding material is simply vapor-deposited, such as ion-assisted vapor deposition or plasma-assisted vapor deposition.

[0023] The effect is attributed to the fact that, compared to other coating methods, the particles or ions generated during sputtering have higher kinetic energy when they collide with the object to be coated, in this case, on an alternating layer sequence. In this way, a higher packing density is generated in the applied anti-corrosion layer, which in turn improves resistance, especially resistance to chemicals.

[0024] In particular, the anti-corrosion layer has a packing density of 90% or more of the theoretically maximum achievable packing density.

[0025] Applying the anti-corrosion layer by sputtering can also reduce the surface roughness of the anti-corrosion layer. Correspondingly, the anti-corrosion layer particularly has a surface roughness R of 0.50 nm or less. a In this manner, the service life of the anti-corrosion layer can be further improved. Surface roughness R a Measurements can be taken according to DIN EN ISO 4287:2010.

[0026] In one variant, the optical element has an increase in reflectivity of 1% or less after six alkaline treatment cycles, wherein the alkaline treatment cycle comprises treating the optical element in an ultrasonic bath at a temperature of 60°C and a power of 300W for one hour, and wherein the ultrasonic bath contains an aqueous potassium hydroxide solution having a potassium hydroxide concentration of 10% by weight of the total weight of the potassium hydroxide solution.

[0027] The alkaline treatment cycle, which involves immersing optical components in an alkaline ultrasonic bath, provides a simple and rapid testing method to examine the resilience of the anti-reflective coating, particularly the resistance of the anti-corrosion layer. Specifically, the stress exerted on the anti-reflective coating in this manner is similar to the conditions exposed to optical components in known cleaning methods used in medical or clinical applications. Therefore, the load during the alkaline treatment cycle, as described above, approximately corresponds to the stress experienced by the optical component during multiple cleaning cycles in an autoclave in medical or clinical settings.

[0028] The increase in reflectance is determined as the average increase in reflectance over a wavelength range of 400 nm to 750 nm. Reflectance can be measured using a spectrophotometer.

[0029] Alternating layer sequences can include one or more sheets, each sheet having a first sublayer and a second sublayer, wherein the refractive index of the first sublayer is lower than that of the second sublayer. The interference behavior of the antireflective coating can be precisely controlled by the sequence of sheets derived from the combination of sublayers with different refractive indices.

[0030] It goes without saying that the selection and arrangement of sublayers of directly adjacent sheets result in an alternating layer sequence. That is, for example, if a sheet has a first sublayer as the uppermost sublayer, then the next sheet further down the substrate has a second sublayer as the lowermost sublayer.

[0031] In one variation, the anti-corrosion layer is applied directly to the first sub-layer of an alternating layer sequence. In other words, the anti-corrosion layer according to this invention follows the first sub-layer, which has a lower refractive index compared to the second sub-layer. Specifically, the anti-corrosion layer has a higher refractive index compared to the first sub-layer, ensuring, in this variation, a sequence of layers with lower and higher refractive indices is achieved. This ensures the desired anti-reflective performance of the anti-reflective coating, thereby achieving either high transmittance or low reflectance.

[0032] Preferably, the optical element has a reflectivity of 0.5% or less, wherein the reflectivity is the average reflectivity in the wavelength range of 400 nm to 750 nm.

[0033] To achieve particularly high transmittance or particularly low reflectance, alternating layer sequences may include at least four layers.

[0034] Preferably, the medical device is an endoscope.

[0035] The term "optical element" includes not only elements that are only at least partially optically transparent, such as windows, but also elements that have optical effects, such as lenses or prisms.

[0036] In applications for medical devices, resistance to chemicals is particularly important because such devices must be cleaned and / or disinfected very frequently, often after each application, especially with the use of corrosive chemicals such as alkaline solutions. Therefore, the chemical resistance or tolerance of the components of optical elements exposed to these chemicals is of particular significance for suitability for use in medical devices.

[0037] Particularly preferred are the optical elements, which are lenses or windows of medical devices, especially lenses or windows of endoscopes.

[0038] Furthermore, the objective of this invention is achieved through the use of an optical element in a medical device, the optical element having a substrate and an antireflective coating applied to a coating surface of the substrate, wherein the antireflective coating comprises an alternating sequence of layers consisting of sublayers with different refractive indices. In addition to the alternating layer sequence, the antireflective coating includes an anti-corrosion layer, which is the layer of the antireflective coating furthest from the coating surface of the substrate. The anti-corrosion layer is designed such that the ratio of the refractive index of the anti-corrosion layer to its thickness in nanometers is in the range of 0.3 to 0.9.

[0039] Optical elements are used, in particular, in medical devices as previously described. The features and characteristics of the medical devices according to this invention are correspondingly adapted to the use of optical elements, and vice versa. Attached Figure Description

[0040] Other features and characteristics derive from the following description of exemplary embodiments and test results, as well as the accompanying drawings, which should not be construed as limiting. The accompanying drawings illustrate:

[0041] - Figure 1 A schematic diagram is shown of an optical element according to the present invention for use in a medical device according to the present invention.

[0042] - Figure 2 A graph showing the reflectivity performance of the optical element according to the comparative example across multiple alkaline treatment cycles, and

[0043] - Figure 3 A graph showing the reflectivity performance of the optical element according to the present invention across multiple alkaline treatment cycles is presented. Detailed Implementation

[0044] exist Figure 1 The image schematically illustrates an optical element 10 according to the present invention for use in a medical device not further shown.

[0045] For example, a medical device is an endoscope, in which optical element 10 is used as a lens or window of the endoscope.

[0046] The optical element 10 includes a substrate 12 and an anti-reflective coating 14 applied to a coating surface 13 of the substrate 12.

[0047] The substrate 12 is made of an optically transparent material, that is, a material that is at least partially transparent to electromagnetic radiation 15, especially to electromagnetic radiation having wavelengths in the range of 400 nm to 750 nm.

[0048] For example, the optically transparent material of the substrate 12 is made of sapphire, glass or quartz.

[0049] It should be understood that the wavelength range of electromagnetic radiation can be designed differently depending on the intended application of the optical element 10.

[0050] The anti-reflective coating 14 has an alternating sequence of layers consisting of sheets 16, each sheet having a first sub-layer 18 and a second sub-layer 20.

[0051] The refractive index of the first sublayer 18 is lower than that of the second sublayer 20 of the corresponding layer 16.

[0052] For example, the refractive index of the first sublayer 18 is in the range of 1.4 to 1.6, while the refractive index of the second sublayer 20 is in the range of 1.9 to 2.4. Therefore, the first sublayer 18 can also be called a "low refractive index sublayer", and the second sublayer 20 can also be called a "high refractive index sublayer".

[0053] For example, the first sublayer 18 is composed of silicon oxide (SiO2, with a refractive index in the range of 1.46 to 1.48), and the second sublayer 20 is composed of Ta2O5 (with a refractive index in the range of 2.10 to 2.20).

[0054] In the illustrated embodiment, the antireflective coating 14 has a total of four layers 16. Of course, the antireflective coating 14 may also have fewer or more layers 16, as long as the desired transmittance or reflectance can be achieved by means of the corresponding number of layers 16.

[0055] Similarly, in Figure 1 In the schematic diagram, all sublayers 18 and 20, and thus all sheets 16, have the same thickness. However, the thicknesses of sublayers 18 and 20, and sheets 16, can also differ from one another.

[0056] According to the present invention, an anti-corrosion layer 22 is additionally applied to the layer sequence composed of layers 16, that is, it is directly applied to the first sub-layer 18 of the uppermost layer in the alternating layer sequence of layers 16, that is, applied to the sub-layer 18 farthest from the substrate 12.

[0057] The anti-corrosion layer 22 is used to protect the alternating layer sequence from damage, especially from damage caused by corrosive chemicals, such as alkaline solutions.

[0058] In the illustrated embodiment, the anti-corrosion layer 22 is made of a high refractive index material selected from the group consisting of zirconium oxide (ZrO2), hafnium oxide (HfO2), and combinations thereof.

[0059] Particularly preferred is that the high refractive index material of the anti-corrosion layer (22) is zirconium oxide (ZrO2).

[0060] This material exhibits high chemical resistance to corrosive chemicals while simultaneously providing protection against mechanical damage.

[0061] The anti-corrosion layer 22 has a layer thickness dk in the range of 3.0 nm to 6.0 nm.

[0062] However, the high refractive index of the material of the anti-corrosion layer 22 may cause an undesirable decrease in the transmittance or an undesirable increase in the reflectance of the optical element 10. To compensate for these effects while maintaining the resistance of the anti-corrosion layer 22 to the anti-reflective coating 14, according to the present invention, the refractive index n of the anti-corrosion layer 22 is... k The thickness d of the anti-corrosion layer 22 is in nanometers. k The ratio α is in the range of 0.3 to 0.9.

[0063] Surprisingly, it is shown that a wear-resistant material can be used in the anti-corrosion layer 22 in the manner described above, the wear-resistant material itself having a relatively high refractive index, while the transmittance or reflectance is at most negligibly impaired.

[0064] The effect is enhanced by sputtering the anti-corrosion layer 22 onto the uppermost sublayer of the first sublayer 18, thereby achieving a high packing density and low surface roughness for the anti-corrosion layer 22.

[0065] Chemical tolerance test

[0066] The effectiveness of the anti-corrosion layer 22 proposed according to this utility model will be further explained below based on the test results.

[0067] Example 1 (Comparative Example)

[0068] An anti-reflective coating is applied to a sapphire substrate and the coating surface of the sapphire substrate. The anti-reflective coating is constructed from a layer sequence consisting of four layers, each layer comprising a low-refractive-index sublayer and a high-refractive-index sublayer. The outermost sublayer of the anti-reflective coating, i.e., the sublayer farthest from the sapphire substrate, is the low-refractive-index sublayer.

[0069] The corresponding sublayers are applied by means of sputtering.

[0070] The anti-reflective coating has the following layer structure, starting from the sapphire substrate: Nb2O5 (d=14nm), SiO2 (d=37nm), Nb2O5 (d=25nm), SiO2 (d=50nm), Nb2O5 (d=11nm), SiO2 (d=335nm), Nb2O5 (d=10.4nm), SiO2 (d=31.6nm), Nb2O5 (d=140nm), and SiO2 (d=79nm).

[0071] Example 2 (Example according to this utility model)

[0072] Similar to the comparative example, the sapphire substrate has an anti-reflective coating on the coated surface of the sapphire substrate as previously described for Example 1, wherein the outermost sublayer composed of SiO2 has a thickness of only 70 nm instead of 79 nm.

[0073] Additionally, the anti-corrosion layer is applied to the uppermost layer of the anti-reflective coating by sputtering, i.e., to the uppermost sublayer of the uppermost layer, which is a low-refractive-index sublayer, wherein the anti-corrosion layer is composed of ZrO2.

[0074] The anti-corrosion layer has a thickness of 5.0 nm and a refractive index of 2.05.

[0075] Tolerance test

[0076] The optical components manufactured according to Examples 1 and 2, under conditions expected in their cleaning cycle in medical applications, are simulated using an alkaline treatment cycle as follows.

[0077] First, the reflectivity R of the manufactured optical element in the wavelength range of 350 nm to 800 nm is determined by means of a spectrophotometer.

[0078] An ultrasonic bath is provided, the ultrasonic bath having an ultrasonic basin with a capacity of 10L. The ultrasonic basin is filled to approximately half full with a potassium hydroxide solution having a potassium hydroxide (KOH) concentration of 10% by weight, and the potassium hydroxide solution is heated to a temperature of 60°C.

[0079] Subsequently, the optical elements to be tested were treated with multiple alkaline treatment cycles, and after each alkaline treatment cycle, the reflectivity R of the optical elements in the wavelength range of 350 nm to 800 nm was determined again by a spectrophotometer.

[0080] The alkali treatment cycle here includes the following steps:

[0081] a) Place the optical element to be tested in the support of the ultrasonic basin so that the optical element is completely covered by potassium hydroxide solution;

[0082] b) Treat the optical element with ultrasound at 60°C and 300W RF power for one hour;

[0083] c) Remove the optical components from the ultrasonic basin, rinse with fresh water, and manually clean the surface.

[0084] Figure 2 The measured reflectance R is shown for Example 1, which is not according to this utility model.

[0085] Initially, the optical element had a reflectivity of approximately 8% in the range of 400 nm to 750 nm (curve 30). The relatively high reflectivity at the beginning is attributed to the use of a sapphire substrate with anti-reflection properties only on one side.

[0086] It can be seen that the reflectance first increases after two alkaline treatment cycles (curve 32), then decreases after three and four alkaline treatment cycles (curves 34 or 36), and then increases again after five and six alkaline treatment cycles (curves 38 or 40).

[0087] exist Figure 2 The curves are also marked with "xh", where "x" indicates the number of hours the optical element has spent in the ultrasonic bath during the alkali treatment cycle. Correspondingly, "0 h" represents the measurement result of the optical element before the first alkali treatment cycle, "2 h" represents the measurement result of the optical element after two alkali treatment cycles, and so on.

[0088] This performance is attributed to the stripping of sublayers with different refractive indices in the optical element's sheet. Therefore, reflectivity increases whenever the uppermost sublayer with the low refractive index is stripped away and a sublayer below it with a higher refractive index is exposed. Reflectivity decreases again whenever the sublayer with the higher refractive index is stripped away again and another sublayer with a low refractive index is exposed.

[0089] However, from Figure 2 As can be seen, the average reflectivity is higher than that in the initial state due to the degradation of the sublayer of the optical element, thus the optical properties of the optical element deteriorate.

[0090] on the contrary, Figure 3 The performance of the optical element according to the present invention is shown in Example 2.

[0091] In this case, it can be seen that the average reflectance has decreased compared to the initial state (curve 42) after one to six alkaline treatment cycles (curve 44 or 46). This effect is attributed to the removal of possible impurities on the surface of the anti-corrosion layer during the first alkaline treatment cycle, and the possible degradation of the anti-corrosion layer within a small range.

[0092] However, the measurement results showed that the performance observed in Comparative Example 1 did not occur, and the optical properties of the optical element were maintained even after multiple alkaline treatment cycles.

Claims

1. A medical device comprising an optical element (10) having a substrate (12) and an anti-reflective coating (14) applied to a coating surface (13) of the substrate (12). The antireflective coating (14) comprises an alternating sequence of sublayers (18, 20) with different refractive indices. In addition to the alternating layer sequence, the antireflective coating (14) includes an anti-corrosion layer (22), which is the layer of the antireflective coating (14) furthest from the coating surface (13) of the substrate (12). The anti-corrosion layer (22) is designed such that the ratio of the refractive index of the anti-corrosion layer (22) to the thickness of the anti-corrosion layer (22) in nanometers is in the range of 0.625 to 0.

9.

2. The medical device according to claim 1, The anti-corrosion layer (22) is made of a high refractive index material selected from the group consisting of zirconium oxide, hafnium oxide and their mixed oxides.

3. The medical device according to claim 2, The anti-corrosion layer (22) is composed of zirconium oxide or hafnium oxide.

4. The medical device according to claim 2, The anti-corrosion layer (22) is composed of zirconium oxide.

5. The medical device according to any one of claims 1 to 4, The anti-corrosion layer (22) has a refractive index in the range of 1.8 to 2.

5.

6. The medical device according to claim 5, The anti-corrosion layer (22) has a refractive index in the range of 1.9 to 2.

2.

7. The medical device according to any one of claims 1 to 4, The anti-corrosion layer (22) has a thickness in the range of 3.0 nm to 6.0 nm.

8. The medical device according to claim 7, The anti-corrosion layer (22) has a thickness in the range of 3.0 nm to 5.0 nm.

9. The medical device according to any one of claims 1 to 4, The anti-corrosion layer (22) is applied by means of sputtering.

10. The medical device according to claim 9, The anti-corrosion layer (22) is applied by means of DC sputtering, radio frequency sputtering, magnetron sputtering or ion beam sputtering.

11. The medical device according to claim 9, The corrosion-resistant layer (22) therein has a packing density of 90% or greater than the theoretically maximum achievable packing density.

12. The medical device according to claim 9, The anti-corrosion layer (22) has a surface roughness R of 0.50 nm or less. a .

13. The medical device according to any one of claims 1 to 4, The optical element (10) has an increase in reflectivity of 1% or less after six alkaline treatment cycles, wherein the alkaline treatment cycle comprises treating the optical element (10) in an ultrasonic bath at a temperature of 60°C and a power of 300W for one hour, wherein the ultrasonic bath contains an aqueous potassium hydroxide solution having a potassium hydroxide concentration of 10% by weight of the total weight of the potassium hydroxide solution.

14. The medical device according to any one of claims 1 to 4, The alternating layer sequence includes one or more sheets (16), each sheet (16) having a first sub-layer (18) and a second sub-layer (20), and the refractive index of the first sub-layer (18) being lower than that of the second sub-layer (20).

15. The medical device according to claim 14, The anti-corrosion layer (22) is applied directly to the first sublayer (18) of the alternating layer sequence.

16. The medical device according to claim 14, The alternating layer sequence mentioned therein comprises at least four layers (16).

17. The medical device according to any one of claims 1 to 4, The medical device mentioned is an endoscope.

18. The medical device according to any one of claims 1 to 4, The optical element (10) therein is a lens or window of the medical device.

19. The medical device according to claim 18, The optical element (10) mentioned therein is a lens or window of an endoscope.

Images