flying object

Abstract

To provide a flying body that can prevent a cover member from being fogged, in a wireless control type flying body in which an imaging device including a cover member is installed.SOLUTION: A wireless control type flying body includes: an imaging device including a lens; and a cover member for covering the lens. The cover member includes: a transparent substrate including a first principal surface and a second principal surface; and a transparent antifogging layer laminated on the first principal surface of the substrate. The cover member is disposed so that the antifogging layer is oriented on a side of the lens.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a radio-controlled flying object, a mobile object, and a cover member. [Background technology]

[0002] In recent years, many radio-controlled flying objects, so-called drones, have been proposed. For example, the drone described in Patent Document 1 is equipped with an imaging device such as a camera, and is capable of taking pictures during flight. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-84868 Summary of the Invention [Problem to be solved by the invention]

[0004] However, drones often ascend and descend repeatedly during flight, resulting in large temperature and pressure changes around the drone, which can cause fogging on the cover member protecting the camera lens. This fogging on the cover member poses a problem, making it difficult to take photographs properly. In particular, because drones are radio-controlled aircraft, even if fogging occurs, the fogging cannot be removed until the drone returns. Therefore, when fogging occurs, the drone has no choice but to stop taking photographs or return. The present invention has been made to solve the above problem, and aims to provide a radio-controlled aircraft equipped with an imaging device having a cover member that can prevent fogging on the cover member. [Means for solving the problem]

[0005] Item 1. A radio-controlled flying object, an imaging device having a lens; a cover member that covers the lens; Equipped with The cover member is a transparent substrate having a first major surface and a second major surface; a transparent anti-fogging layer laminated on the first main surface of the substrate; Equipped with The cover member is arranged so that the anti-fogging layer faces the lens.

[0006] Item 2. The aircraft described in Item 1, configured to be capable of moving underwater.

[0007] Item 3. A cover member provided on a radio-controlled flying object equipped with an imaging device having a lens, a transparent substrate having a first major surface and a second major surface; a transparent anti-fogging layer laminated on the first main surface of the substrate; Equipped with A cover member, wherein the anti-fogging layer is arranged to face the lens side.

[0008] Item 4. Unmanned or manned mobile objects, an imaging device having a lens; a cover member that covers the lens; Equipped with The cover member is a transparent substrate having a first major surface and a second major surface; a transparent anti-fogging layer laminated on the first main surface of the substrate; Equipped with the cover member is disposed so that the anti-fogging layer faces the lens side, The control method is selected from radio control, autonomous control, direct control by a human, or a combination thereof; A vehicle that is at least one of an air vehicle, a land vehicle, a surface vehicle, and an underwater vehicle (excluding conventional automobiles, airplanes, helicopters, ships, and submarines). [Effects of the Invention]

[0009] According to the present invention, in a wirelessly controlled flying object equipped with an imaging device having a cover member, clouding of the cover member can be prevented.

Brief Description of the Drawings

[0010] [Figure 1] It is a cross-sectional view showing a first embodiment of a cover member according to the present invention. [Figure 2] It is a schematic side view of a drone according to a first embodiment of the present invention. [Figure 3] It is a cross-sectional view showing a second embodiment of a cover member according to the present invention. [Figure 4] It is a cross-sectional view showing a schematic configuration of a second functional layer as an antireflection layer. [Figure 5] It is a cross-sectional view showing another example of the cover member of the second embodiment. [Figure 6] It is a cross-sectional view showing another example of the cover member of the second embodiment. [[ID=2�]] [Figure 7] It is a cross-sectional view showing another example of the cover member of the second embodiment.

Modes for Carrying Out the Invention

[0011] <A. First Embodiment> Hereinafter, a first embodiment of a cover member of the present invention and a wirelessly controlled flying object (drone) provided with the same will be described with reference to the drawings. FIG. 1 is a cross-sectional view of the cover member.

[0012] <1. Outline of the Cover Member> The cover member according to the present embodiment is arranged in front of a lens of an imaging device such as a camera, for example, and protects the lens and the like, as will be described later. Specifically, as shown in FIG. 1, the cover member 10 has a transparent base material 1 having a first main surface 11 and a second main surface 12, and a first functional layer 2 laminated on the first main surface 11 of the base material 1. Hereinafter, each member will be described in detail.

[0013] <2. Base Material> The substrate 1 can be formed from a translucent resin material (organic polymer material) or a glass plate. The shape of the substrate is not particularly limited, and can be circular, rectangular, polygonal, irregular, or the like, and can be appropriately determined depending on various uses as described below. Specific examples will be described below.

[0014] <2-1. Resin materials> The resin material is not particularly limited as long as it has the translucency as described above, but it can be formed from, for example, polycarbonate (PC), acrylonitrile / styrene resin (AS), acrylonitrile / butadiene / styrene resin (ABS), methacrylic resin (PMMA), polyvinyl chloride (PVC), etc., or a material containing two or more of these.

[0015] <2-2. Glass Plate> There are no particular limitations on the glass plate 1, and any known transparent glass plate can be used, including, for example, float glass, heat-absorbing glass, clear glass, green glass, UV-green glass, and soda-lime glass.

[0016] Examples of compositions of clear glass, heat-absorbing glass, soda-lime glass, and float glass are shown below.

[0017] <2-2-1. Clear glass> SiO2:70~73% by mass Al2O3:0.6~2.4% by mass CaO: 7~12% by mass MgO: 1.0~4.5% by mass RO: 13 to 15 mass% (R is an alkali metal) Total iron oxide converted to Fe2O3 (T-Fe2O3): 0.08 to 0.14 mass%

[0018] <2-2-2. Heat-absorbing glass> The composition of the heat ray absorbing glass can be, for example, based on the composition of clear glass, with the ratio of total iron oxide (T-Fe2O3) converted to Fe2O3 being 0.4 to 1.3 mass%, the ratio of CeO2 being 0 to 2 mass%, and the ratio of TiO2 being 0 to 0.5 mass%, and the amount of the glass framework components (mainly SiO2 and Al2O3) reduced by the amount of the increase in T-Fe2O3, CeO2, and TiO2.

[0019] <2-2-3. Soda-lime glass> SiO2: 65~80% by mass Al2O3: 0~5% by mass CaO: 5~15% by mass MgO: 2% by mass or more NaO: 10~18% by mass K2O: 0~5% by mass MgO+CaO: 5~15% by mass Na2O+K2O: 10~20% by mass SO3:0.05~0.3% by mass B2O3:0~5% by mass Total iron oxide (T-Fe2O3) converted to Fe2O3: 0.02 to 0.03 mass%

[0020] <2-2-4. Float glass> SiO2 65-80% Al2O30-5% MgO 0-20% CaO 0-20% Na2O 10-20% K2O 0~5%

[0021] <2-2-4-1. Highly transparent float glass> SiO2 66~72% Al2O3 2~4% MgO 8~15% CaO 1-8% Na2O 12~16% K2O 0~1% Including, MgO + CaO is in the range of 12-17%. Molar ratio CaO / (MgO+CaO) is 0.1 to 0.4

[0022] Each component constituting the composition of this float glass will be explained below. (SiO2) SiO2 is a major component constituting the glass plate 1, and if its content is too low, the chemical durability, such as water resistance, and heat resistance of the glass will decrease. On the other hand, if the SiO2 content is too high, the viscosity of the glass plate 1 will increase at high temperatures, making it difficult to melt and form. Therefore, the SiO2 content is appropriately in the range of 66 to 72 mol%, and preferably 67 to 70 mol%.

[0023] (Al2O3) Al2O3 is a component that improves the chemical durability of the glass sheet 1, such as water resistance, and also increases the surface compressive stress after chemical strengthening by facilitating the movement of alkali metal ions in the glass, and deepens the depth of the stress layer. On the other hand, if the Al2O3 content is too high, it increases the viscosity of the glass melt, increasing T2 and T4, and also worsening the clarity of the glass melt, making it difficult to produce high-quality glass sheets. In the float process, the working temperature is set at a temperature where the glass viscosity is 10 4 The melting temperature is the temperature at which the glass viscosity becomes 10 2 This is the temperature at which the viscosity becomes dPa·s, hereafter referred to as T2.

[0024] Therefore, the Al2O3 content is preferably in the range of 1 to 4 mol %. The Al2O3 content is preferably 3 mol % or less, and more preferably 2 mol % or more.

[0025] (MgO) MgO is an essential component for improving the meltability of glass. To fully achieve this effect, the MgO content in this glass plate 1 is 8 mol% or more. Furthermore, if the MgO content is below 8 mol%, the surface compressive stress after chemical strengthening tends to decrease, and the depth of the stress layer tends to become shallower. On the other hand, if the content is increased beyond an appropriate amount, the strengthening performance obtained by chemical strengthening decreases, and in particular, the depth of the surface compressive stress layer rapidly becomes shallower. This adverse effect is least pronounced among alkaline earth metal oxides, but in this glass plate 1, the MgO content is 15 mol% or less. Furthermore, if the MgO content is high, T2 and T4 increase and the clarity of the glass melt deteriorates, making it difficult to produce high-quality glass plates.

[0026] Therefore, in the glass plate 1, the content of MgO is in the range of 8 to 15 mol %, and preferably 12 mol % or less.

[0027] (CaO) CaO has the effect of reducing viscosity at high temperatures, but if the content is too high beyond a moderate range, the glass sheet 1 becomes more susceptible to devitrification and inhibits the migration of sodium ions in the glass sheet 1. When CaO is not contained, the surface compressive stress after chemical strengthening tends to decrease. On the other hand, if CaO is contained in an amount exceeding 8 mol%, the surface compressive stress after chemical strengthening decreases significantly, the depth of the compressive stress layer becomes significantly shallower, and the glass sheet 1 becomes more susceptible to devitrification.

[0028] Therefore, the CaO content is preferably in the range of 1 to 8 mol %. The CaO content is preferably 7 mol % or less, and more preferably 3 mol % or more.

[0029] (SrO, BaO) SrO and BaO significantly reduce the viscosity of the glass plate 1, and even a small amount of SrO and BaO can reduce the liquidus temperature T L However, even when added in small amounts, SrO and BaO significantly hinder the migration of sodium ions in the glass plate 1, significantly reducing the surface compressive stress and making the depth of the compressive stress layer considerably shallower.

[0030] Therefore, it is preferable that the glass plate 1 contains substantially no SrO or BaO.

[0031] (RO) In this embodiment, RO represents the sum of MgO and CaO. If the RO content is too low, the components that reduce the viscosity of the glass plate 1 are insufficient, making it difficult to melt. On the other hand, if the RO content is too high, the surface compressive stress is significantly reduced, the depth of the compressive stress layer becomes significantly shallower, and the liquidus temperature T L tends to rise sharply.

[0032] Therefore, the RO content is preferably in the range of 12 to 17 mol %. The RO content is preferably 14 mol % or more and 16 mol % or less.

[0033] Furthermore, when the molar ratio of CaO to RO, CaO / RO, is in the range of 0.1 to 0.4, the liquidus temperature tends to be particularly low. Therefore, a molar ratio of 0.1 to 0.4 is appropriate. Furthermore, while lowering this molar ratio can improve the depth of the surface compressive stress and compressive stress layer, T2 and T4 increase, resulting in a significant deviation from the SL in the strict sense, making it difficult to manufacture glass articles. Therefore, this molar ratio is preferably 0.2 or more and 0.3 or less.

[0034] (Na2O) Na2O is a component that increases the surface compressive stress and deepens the depth of the surface compressive stress layer by substituting sodium ions for potassium ions. However, if the content is increased beyond an appropriate amount, the stress relaxation during the chemical strengthening process tends to exceed the surface compressive stress generated by ion exchange during the chemical strengthening process, resulting in a decrease in the surface compressive stress.

[0035] Furthermore, while Na2O is a component that improves solubility and reduces T4 and T2, if the Na2O content is too high, the water resistance of the glass will be significantly reduced. In the glass plate 1, if the Na2O content is 12 mol% or more, the effect of reducing T4 and T2 is sufficiently obtained, but if it exceeds 16 mol%, the reduction in surface compressive stress due to stress relaxation will be significant.

[0036] Therefore, the Na2O content in the glass plate 1 of this embodiment is suitably in the range of 12 to 16 mol %. The Na2O content is preferably 13 mol % or more, and more preferably 15 mol % or less.

[0037] (K2O) Like NaO, KO is a component that improves the melting point of glass. In addition, when the KO content is low, the ion exchange rate during chemical strengthening increases, and the depth of the surface compressive stress layer increases. However, the liquidus temperature T L Therefore, it is preferable to add K2O at a low content.

[0038] On the other hand, compared with Na2O, K2O has a smaller effect on lowering T4 and T2, but a large amount of K2O inhibits the clarification of the glass melt. Also, the higher the K2O content, the lower the surface compressive stress after chemical strengthening. Therefore, a K2O content in the range of 0 to 1 mol% is appropriate.

[0039] (LiO) Even a small amount of Li2O significantly reduces the depth of the compressive stress layer. Furthermore, when a glass article containing Li2O is chemically strengthened using a molten salt of potassium nitrate alone, the molten salt deteriorates significantly faster than a glass article that does not contain Li2O. Specifically, when repeated chemical strengthening treatments are performed using the same molten salt, the surface compressive stress formed on the glass surface decreases with fewer treatments. Therefore, the glass plate 1 of this embodiment may contain 1 mol% or less of Li2O, but it is preferable that it contains substantially no Li2O.

[0040] (B2O3) B2O3 is a component that reduces the viscosity of the glass plate 1 and improves its melting point. However, if the B2O3 content is too high, the glass plate 1 is prone to phase separation, reducing its water resistance. Furthermore, compounds formed by B2O3 and alkali metal oxides may volatilize and damage the refractories in the glass melting chamber. Furthermore, the inclusion of B2O3 reduces the depth of the compressive stress layer formed during chemical strengthening. Therefore, a B2O3 content of 0.5 mol% or less is appropriate. In the present invention, it is more preferable that the glass plate 1 contains substantially no B2O3.

[0041] (Fe2O3) Usually, Fe is 2+ or Fe 3+ It exists in glass in the form of Fe and acts as a colorant. 3+ is a component that enhances the ultraviolet absorption performance of glass, and Fe 2+ is a component that enhances heat ray absorption performance. When the glass plate 1 is used as a cover glass for a display, a low Fe content is preferable because inconspicuous coloring is required. However, Fe is often inevitably mixed in as an industrial raw material. Therefore, the iron oxide content, converted to Fe2O3, is preferably 0.15% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.02% by mass or less, assuming that the entire glass plate 1 is 100% by mass. In particular, the high-transmittance float glass described above can achieve high transmittance because of its low Fe content. For example, with a thickness of 0.55 mm, a transmittance of 91% to 100% for light with a wavelength of 550 nm can be achieved.

[0042] (TiO2) TiO2 is a component that reduces the viscosity of the glass plate 1 and at the same time increases the surface compressive stress due to chemical strengthening, but it may impart a yellow color to the glass plate 1. Therefore, a TiO2 content of 0 to 0.2 mass % is appropriate. TiO2 is unavoidably mixed in with commonly used industrial raw materials, and may be contained in the glass plate 1 at about 0.05 mass %. This level of content does not impart color to the glass, and therefore may be included in the glass plate 1 of the present embodiment.

[0043] (ZrO2) ZrO2 is sometimes mixed into glass sheet 1 from the refractory bricks that make up the glass melting furnace, especially when manufacturing glass sheets using the float process, and its content is known to be around 0.01% by mass. On the other hand, ZrO2 is a component that improves the water resistance of glass and also increases the surface compressive stress due to chemical strengthening. However, a high ZrO2 content can increase the working temperature T4 and the liquidus temperature T L Furthermore, when glass sheets are manufactured by the float process, the precipitated Zr-containing crystals tend to remain as foreign matter in the manufactured glass. Therefore, the ZrO2 content is preferably 0 to 0.1 mass%.

[0044] (SO3) In the float process, sulfates such as Glauber's salt (Na2SO4) are commonly used as fining agents. Sulfates decompose in molten glass to produce gas components, which promote degassing of the glass melt, but some of the gas components dissolve and remain in the glass plate 1 as SO3. In the glass plate 1 of the present invention, the SO3 content is preferably 0 to 0.3 mass %.

[0045] (CeO2) CeO2 is used as a fining agent. CeO2 generates O2 gas in the molten glass, so CeO2 contributes to defoaming. On the other hand, if there is too much CeO2, the glass will turn yellow. Therefore, the CeO2 content is preferably 0 to 0.5 mass%, more preferably 0 to 0.3 mass%, and even more preferably 0 to 0.1 mass%.

[0046] (SnO2) It is known that in glass sheets formed by the float process, tin diffuses from the tin bath to the surface that comes into contact with the tin bath during forming, and the tin exists as SnO2. Furthermore, SnO2 mixed into the glass raw materials contributes to degassing. In the glass sheet 1 of the present invention, the SnO2 content is preferably 0 to 0.3 mass%.

[0047] (Other ingredients) The glass plate 1 according to the present embodiment is preferably substantially composed of the components listed above, but may also contain components other than those listed above, preferably in such a range that the content of each component is less than 0.1% by mass.

[0048] In addition to the aforementioned SO3 and SnO2, examples of components that may be included include As2O5, Sb2O5, Cl, and F, which are added for the purpose of degassing molten glass. However, it is preferable not to add As2O5, Sb2O5, Cl, and F due to their significant adverse environmental impact. Other examples of components that may be included include ZnO, P2O5, GeO2, Ga2O3, Y2O3, and La2O3. Components other than those mentioned above derived from industrially used raw materials are also allowed as long as their content does not exceed 0.1% by mass. Because these components are added as needed or are unavoidably mixed in, the glass plate 1 of this embodiment may be substantially free of these components.

[0049] (Density (specific gravity):d) From the above composition, in this embodiment, the density of the glass plate 1 is set to 2.53 g cm -3 Below, 2.51 g cm -3 Below 2.50 g·cm in some cases -3 It can be reduced to the following:

[0050] In processes such as the float process, if there is a large difference in density between glass types, the molten glass with a higher density may remain at the bottom of the furnace when switching between glass types, which can cause problems when switching between types. The density of soda-lime glass currently mass-produced using the float process is approximately 2.50 g cm -3 Therefore, when considering mass production using the float method, the density of the glass plate 1 should be close to the above value, specifically, 2.45 to 2.55 g cm -3 , especially 2.47 to 2.53 g cm -3 is preferred, and 2.47 to 2.50 g cm -3 is more preferable.

[0051] (Elastic modulus: E) Chemical strengthening involving ion exchange can cause warping of the glass substrate. To prevent this warping, it is preferable that the elastic modulus of the glass plate 1 is high. According to the present invention, the elastic modulus (Young's modulus: E) of the glass plate 1 can be increased to 70 GPa or more, and even 72 GPa or more.

[0052] (thermal expansion coefficient) In particular, the above-mentioned high-transmittance float glass has a thermal expansion coefficient of 50×10 between 50°C and 350°C. -7 ~100×10 -7 / K% or less can be achieved.

[0053] <2-2-5. Orientation of the glass plate> In a glass sheet produced by the float process, the surface that was in contact with the molten metal is referred to as the bottom surface, and the opposite surface is referred to as the top surface. The bottom surface and the top surface may be unpolished. Since the bottom surface was in contact with the molten metal, if the molten metal is tin, the concentration of tin oxide contained in the bottom surface will be greater than the concentration of tin oxide contained in the top surface.

[0054] As described above, the bottom surface has a high tin oxide concentration, which is effective in suppressing the elution of alkaline components contained in the glass plate. To suppress a decrease in durability due to alkaline elution, the above-described first functional layer 2 can be laminated on the bottom surface. On the other hand, the top surface has a low tin oxide concentration, resulting in a relatively high concentration of SiOH groups on the surface. Therefore, to enhance adhesion by utilizing the chemical bond between the OH groups in the first functional layer 2 and the surface SiOH groups, the first functional layer 2 can be laminated on the top surface. Furthermore, to avoid the effects of trace metals (tin), the bottom surface can be polished with an abrasive such as cerium oxide, and the first functional layer 2 can be laminated on the bottom surface, the top surface, or both the bottom and top surfaces. The above points apply not only to the first functional layer 2 but also to the other functional layers described in this specification.

[0055] <2-2-6. Thickness of glass plate> The thickness of the glass plate 1 is not particularly limited, but is preferably 0.2 mm to 10 mm, and more preferably 0.5 mm to 4 mm. If the thickness of the glass plate 1 is less than 0.2 mm, the rigidity may decrease, while if the thickness of the glass plate 1 is greater than 10 mm, the weight may increase. Furthermore, as described above, even if the substrate 1 is made of a resin material, it can have the same thickness as a glass plate.

[0056] <3. 1st functional layer> The first functional layer 2 can be composed of a film having various functions. For example, a heat-shielding film (heat-reflecting film) or an anti-fogging layer (or anti-fogging sheet) can be used. The heat-shielding film is a known film configured to reflect or absorb infrared rays in order to suppress a rise in temperature of the imaging device. Such a film can be attached to the first main surface 11 of the substrate 1 with an adhesive, or a film having a heat-shielding function can be laminated on the first main surface 11 by coating. The following is another example of the first functional layer 2. An anti-fogging layer will be described in detail.

[0057] <3-1. Anti-fogging layer> The anti-fogging layer is not particularly limited as long as it exhibits an anti-fogging effect on the substrate 1, and known anti-fogging layers can be used. Generally, anti-fogging layers are classified into hydrophilic types that form a water film on the surface from water generated from water vapor, water-absorbing types that absorb water vapor, water-repellent and water-absorbing types that make it difficult for water droplets to condense on the surface, and water-repellent types that repel water droplets generated from water vapor, and any type of anti-fogging layer can be used. Below, an example of a water-repellent and water-absorbing type anti-fogging layer will be described. [Organic-inorganic composite anti-fog layer] The organic-inorganic composite anti-fogging layer is a single layer film or a laminated multi-layer film formed on the surface of any one of the functional layers. The organic-inorganic composite anti-fogging layer contains at least a water-absorbing resin, a water-repellent group, and a metal oxide component. The anti-fogging layer may further contain other functional components as necessary. Any type of water-absorbing resin can be used as long as it is a resin that can absorb and retain water. The water-repellent group can be supplied to the anti-fogging layer from a metal compound having a water-repellent group (a metal compound containing a water-repellent group). The metal oxide component can be supplied to the anti-fogging layer from a metal compound containing a water-repellent group, other metal compounds, metal oxide fine particles, etc. Each component will be described below.

[0058] (Water absorbent resin) The water-absorbent resin is not particularly limited, and examples thereof include polyethylene glycol, polyether resins, polyurethane resins, starch resins, cellulose resins, acrylic resins, epoxy resins, polyester polyols, hydroxyalkyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acetal resins, polyvinyl acetate, etc. Among these, preferred are hydroxyalkyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acetal resins, polyvinyl acetate, epoxy resins, and polyurethane resins, more preferred are polyvinyl acetal resins, epoxy resins, and polyurethane resins, and particularly preferred is polyvinyl acetal resin.

[0059] Polyvinyl acetal resins can be obtained by acetalizing polyvinyl alcohol by a condensation reaction with an aldehyde. The acetalization of polyvinyl alcohol can be carried out by a known method such as a precipitation method using an aqueous medium in the presence of an acid catalyst or a dissolution method using a solvent such as alcohol. The acetalization can also be carried out in parallel with the saponification of polyvinyl acetate. The acetalization degree is preferably 2 to 40 mol%, more preferably 3 to 30 mol%, particularly preferably 5 to 20 mol%, and in some cases 5 to 15 mol%. The acetalization degree can be, for example, 13 The degree of acetalization can be measured by C nuclear magnetic resonance spectroscopy. A polyvinyl acetal resin having an acetalization degree within the above range is suitable for forming an organic-inorganic composite anti-fogging layer having good water absorbency and water resistance.

[0060] The average degree of polymerization of polyvinyl alcohol is preferably 200 to 4500, more preferably 500 to 4500. A high average degree of polymerization is advantageous for forming an organic-inorganic composite anti-fogging layer with good water absorption and water resistance, but if the average degree of polymerization is too high, the viscosity of the solution becomes too high, which may hinder film formation. The saponification degree of polyvinyl alcohol is preferably 75 to 99.8 mol%.

[0061] Examples of aldehydes to be condensed with polyvinyl alcohol include aliphatic aldehydes such as formaldehyde, acetaldehyde, butylaldehyde, hexylcarbaldehyde, octylcarbaldehyde, and decylcarbaldehyde. Other examples include benzaldehyde; 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, and other alkyl-substituted benzaldehydes; chlorobenzaldehyde and other halogen-substituted benzaldehydes; substituted benzaldehydes in which hydrogen atoms are substituted with functional groups other than alkyl groups, such as hydroxy groups, alkoxy groups, amino groups, and cyano groups; and condensed aromatic ring aldehydes such as naphthaldehyde and anthraldehyde. Aromatic aldehydes with strong hydrophobicity are advantageous for forming an organic-inorganic composite anti-fogging layer with a low degree of acetalization and excellent water resistance. The use of an aromatic aldehyde is advantageous in that it allows the formation of a film with high water absorption while leaving many hydroxyl groups. The polyvinyl acetal resin preferably contains an acetal structure derived from an aromatic aldehyde, particularly benzaldehyde.

[0062] Examples of epoxy resins include glycidyl ether epoxy resins, glycidyl ester epoxy resins, glycidyl amine epoxy resins, alicyclic epoxy resins, etc. Among these, alicyclic epoxy resins are preferred.

[0063] The polyurethane resin may be a polyurethane resin composed of a polyisocyanate and a polyol, and the polyol is preferably an acrylic polyol or a polyoxyalkylene polyol.

[0064] The organic-inorganic composite anti-fogging layer contains a water-absorbing resin as its main component. In the present invention, the term "main component" refers to the component with the highest content by mass. From the viewpoints of film hardness, water absorbency, and anti-fogging properties, the content of the water-absorbing resin based on the weight of the organic-inorganic composite anti-fogging layer is preferably 50% by weight or more, more preferably 60% by weight or more, and particularly preferably 65% ​​by weight or more, and is 95% by weight or less, more preferably 90% by weight or less.

[0065] (water-repellent base) To fully obtain the above-mentioned effects of the water-repellent group, it is preferable to use a water-repellent group with high water repellency. The preferred water-repellent group is at least one selected from (1) linear or cyclic alkyl groups having 3 to 30 carbon atoms, and (2) linear or cyclic alkyl groups having 1 to 30 carbon atoms in which at least a portion of the hydrogen atoms has been substituted with fluorine atoms (hereinafter, sometimes referred to as "fluorine-substituted alkyl groups").

[0066] With regard to (1) and (2), the linear or cyclic alkyl group is preferably a linear alkyl group. The linear alkyl group may be a branched alkyl group, but is preferably a linear alkyl group. An alkyl group having more than 30 carbon atoms may cause the anti-fogging layer to become cloudy. From the viewpoint of the balance between the anti-fogging properties, strength, and appearance of the film, the number of carbon atoms in the alkyl group is preferably 20 or less, more preferably 6 to 14. Particularly preferred alkyl groups are linear alkyl groups having 6 to 14 carbon atoms, particularly 6 to 12 carbon atoms, such as n-hexyl (6 carbon atoms), n-decyl (10 carbon atoms), and n-dodecyl (12 carbon atoms). With regard to (2), the fluorine-substituted alkyl group may be a group in which only a portion of the hydrogen atoms of a linear or cyclic alkyl group are substituted with fluorine atoms, or may be a group in which all of the hydrogen atoms of a linear or cyclic alkyl group are substituted with fluorine atoms, such as a linear perfluoroalkyl group. Fluorine-substituted alkyl groups have high water repellency, so sufficient effects can be obtained by adding a small amount. However, if the content of the fluorine-substituted alkyl group is too high, it may separate from other components in the coating liquid used to form the film.

[0067] (Hydrolyzable metal compounds with water-repellent groups) To incorporate water-repellent groups into the anti-fogging layer, a metal compound having a water-repellent group (water-repellent group-containing metal compound), particularly a metal compound having a water-repellent group and a hydrolyzable functional group or a halogen atom (water-repellent group-containing hydrolyzable metal compound) or its hydrolyzate may be added to the coating liquid for forming the film. In other words, the water-repellent group may be derived from a water-repellent group-containing hydrolyzable metal compound. A suitable water-repellent group-containing hydrolyzable metal compound is a water-repellent group-containing hydrolyzable silicon compound represented by the following formula (I): R m SiY 4-m (I) Here, R is a water-repellent group, i.e., a linear or cyclic alkyl group having 1 to 30 carbon atoms in which at least a portion of the hydrogen atoms may be substituted with fluorine atoms; Y is a hydrolyzable functional group or a halogen atom; and m is an integer of 1 to 3. The hydrolyzable functional group is, for example, at least one selected from an alkoxyl group, an acetoxy group, an alkenyloxy group, and an amino group, and is preferably an alkoxy group, particularly an alkoxy group having 1 to 4 carbon atoms. An example of an alkenyloxy group is an isopropenoxy group. The halogen atom is preferably chlorine. The functional groups exemplified here can also be used as the "hydrolyzable functional group" described below. m is preferably 1 to 2.

[0068] Upon completion of hydrolysis and polycondensation, the compound represented by formula (I) provides a component represented by formula (II): R m SiO (4-m) / 2 (II) where R and m are as defined above. After hydrolysis and polycondensation, the compound represented by formula (II) actually forms a network structure in the anti-fogging layer in which silicon atoms are bonded to each other via oxygen atoms.

[0069] In this way, the compound represented by formula (I) undergoes hydrolysis or partial hydrolysis, and further undergoes at least partial polycondensation to form a network structure of siloxane bonds (Si-O-Si) in which silicon atoms and oxygen atoms are alternately connected and spread three-dimensionally. Water-repellent groups R are connected to the silicon atoms in this network structure. In other words, the water-repellent groups R are fixed to the network structure of siloxane bonds via R-Si bonds. This structure is advantageous for uniformly dispersing the water-repellent groups R in the film. The network structure may contain silica components provided by silicon compounds other than the water-repellent group-containing hydrolyzable silicon compound represented by formula (I) (e.g., tetraalkoxysilane, silane coupling agent). When a silicon compound having no water-repellent groups but a hydrolyzable functional group or a halogen atom (water-repellent group-free hydrolyzable silicon compound) is blended with the water-repellent group-containing hydrolyzable silicon compound in a coating liquid for forming an anti-fogging layer, a network structure of siloxane bonds containing silicon atoms bonded to water-repellent groups and silicon atoms not bonded to water-repellent groups can be formed. With such a structure, it becomes easy to adjust the content of the water-repellent group and the content of the metal oxide component in the anti-fogging layer independently of each other.

[0070] Water-repellent groups have the effect of improving the anti-fogging performance by increasing the water vapor permeability on the surface of an anti-fogging layer containing a water-absorbent resin. Because the two functions of water absorption and water repellency are mutually exclusive, water-absorbent materials and water-repellent materials have traditionally been provided in separate layers. However, water-repellent groups eliminate uneven distribution of water near the surface of the anti-fogging layer, extending the time until condensation occurs and improving the anti-fogging properties of an anti-fogging layer with a single-layer structure. The effects of these groups are explained below.

[0071] Water vapor that penetrates an anti-fogging layer containing a water-absorbing resin forms hydrogen bonds with hydroxyl groups of the water-absorbing resin and is retained in the form of bound water. As the amount increases, water vapor progresses from bound water to semi-bound water and finally to free water retained in the voids in the anti-fogging layer. In the anti-fogging layer, water-repellent groups hinder the formation of hydrogen bonds and facilitate the dissociation of formed hydrogen bonds. If the water-absorbent resin content is the same, there is no difference in the number of hydroxyl groups capable of hydrogen bonding in the film, but the water-repellent groups slow down the rate of hydrogen bond formation. Therefore, in an anti-fogging layer containing water-repellent groups, water will ultimately be retained in the film in one of the above forms, but before it is retained, it can diffuse as water vapor to the bottom of the film. Furthermore, once retained, water dissociates relatively easily and tends to migrate to the bottom of the film in the form of water vapor. As a result, the distribution of water retention in the thickness direction of the film is relatively uniform from near the surface to the bottom of the film. In other words, the entire thickness of the anti-fogging layer is effectively utilized to absorb water supplied to the film surface, which makes it difficult for water droplets to condense on the surface and improves anti-fogging properties. Furthermore, since water droplets are difficult to condense on the surface, the anti-fogging layer that has absorbed moisture has the characteristic of being difficult to freeze even at low temperatures.

[0072] On the other hand, in an anti-fogging layer that does not contain water-repellent groups, water vapor that penetrates into the film is very easily retained in the form of bound water, semi-bound water, or free water. Therefore, the penetrated water vapor tends to be retained near the surface of the film. As a result, the moisture content in the film is extremely high near the surface and rapidly decreases as it progresses toward the bottom of the film. In other words, although the bottom of the film can still absorb water, the film near the surface is saturated with moisture and condenses as water droplets, resulting in limited anti-fogging properties.

[0073] When a water-repellent group-containing hydrolyzable silicon compound (see formula (I)) is used to introduce a water-repellent group into the anti-fogging layer, a strong network structure of siloxane bonds (Si-O-Si) is formed. The formation of this network structure is advantageous not only from the viewpoint of improving abrasion resistance but also from the viewpoint of improving hardness, water resistance, etc.

[0074] The water-repellent groups should be added to the extent that the water contact angle on the surface of the anti-fogging layer is 70 degrees or more, preferably 80 degrees or more, and more preferably 90 degrees or more. The water contact angle is measured by dropping a 4 mg water droplet on the surface of the film. In particular, when methyl or ethyl groups, which have relatively weak water repellency, are used as the water-repellent groups, it is preferable to incorporate water-repellent groups in the anti-fogging layer in an amount that will result in a water contact angle in the above-mentioned range. There is no particular upper limit for this water droplet contact angle, but it is, for example, 150 degrees or less, for example, 120 degrees or less, or even 100 degrees or less. It is preferable that the water-repellent groups be uniformly incorporated into the anti-fogging layer so that the water droplet contact angle is in the above-mentioned range throughout the entire surface of the anti-fogging layer.

[0075] The surface of the anti-fogging layer can also be made water-repellent, which can prevent alkaline components from penetrating into the anti-fogging layer and protect the surface of the glass plate 1 from alkaline components.

[0076] The anti-fogging layer preferably contains water-repellent groups in an amount of 0.05 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, relative to 100 parts by mass of the water-absorbent resin, and in an amount of 10 parts by mass or less, preferably 5 parts by mass or less.

[0077] (inorganic oxides) The inorganic oxide is, for example, an oxide of at least one element selected from Si, Ti, Zr, Ta, Nb, Nd, La, Ce, and Sn, and includes at least an oxide of Si (silica). The organic-inorganic composite anti-fogging layer preferably contains at least 0.01 parts by weight of inorganic oxide per 100 parts by weight of the water-absorbent resin, more preferably at least 0.1 parts by weight, even more preferably at least 0.2 parts by weight, particularly preferably at least 1 part by weight, most preferably at least 5 parts by weight, in some cases at least 10 parts by weight, and if necessary at least 20 parts by weight, and preferably at most 50 parts by weight, more preferably at most 45 parts by weight, even more preferably at most 40 parts by weight, particularly preferably at most 35 parts by weight, most preferably at most 33 parts by weight, and in some cases at most 30 parts by weight. The inorganic oxide is a necessary component for ensuring the strength, particularly abrasion resistance, of the organic-inorganic composite anti-fogging layer, but if the inorganic oxide content is high, the anti-fogging properties of the organic-inorganic composite anti-fogging layer will decrease.

[0078] (Inorganic oxide fine particles) The organic-inorganic composite anti-fogging layer may further contain inorganic oxide fine particles as at least a portion of the inorganic oxide. The inorganic oxide constituting the inorganic oxide fine particles is, for example, an oxide of at least one element selected from Si, Ti, Zr, Ta, Nb, Nd, La, Ce, and Sn, preferably silica fine particles. Silica fine particles can be introduced into the organic-inorganic composite anti-fogging layer, for example, by adding colloidal silica. Inorganic oxide fine particles are excellent at transmitting stress applied to the organic-inorganic composite anti-fogging layer to the article supporting the organic-inorganic composite anti-fogging layer and also have high hardness. Therefore, the addition of inorganic oxide fine particles is advantageous from the perspective of improving the abrasion resistance of the organic-inorganic composite anti-fogging layer. Furthermore, the addition of inorganic oxide fine particles to the organic-inorganic composite anti-fogging layer forms fine voids where the fine particles are in contact with or adjacent to each other, making it easier for water vapor to be absorbed into the film through these voids. Therefore, the addition of inorganic oxide fine particles may be advantageous in improving anti-fogging properties. The inorganic oxide fine particles can be supplied to the organic-inorganic composite anti-fogging layer by adding pre-formed inorganic oxide fine particles to a coating liquid for forming the organic-inorganic composite anti-fogging layer.

[0079] If the average particle size of inorganic oxide particles is too large, the organic-inorganic composite anti-fogging layer may become cloudy. If the average particle size is too small, the particles may aggregate and become difficult to uniformly disperse. From this perspective, the average particle size of inorganic oxide particles is preferably 1 to 20 nm, more preferably 5 to 20 nm. Here, the average particle size of inorganic oxide particles is described in terms of primary particles. The average particle size of inorganic oxide particles is determined by measuring the particle sizes of 50 randomly selected particles through observation using a scanning electron microscope and adopting the average value. If the content of inorganic oxide particles is too high, the water absorption capacity of the organic-inorganic composite anti-fogging layer as a whole may decrease, potentially causing the organic-inorganic composite anti-fogging layer to become cloudy. The inorganic oxide particles are added in an amount of preferably 0 to 50 parts by weight, more preferably 2 to 30 parts by weight, even more preferably 5 to 25 parts by weight, and particularly preferably 10 to 20 parts by weight, per 100 parts by weight of the water-absorbent resin.

[0080] (Hydrolyzable metal compounds without water-repellent groups) The anti-fogging layer may contain a metal oxide component derived from a hydrolyzable metal compound that does not have a water-repellent group (a hydrolyzable compound that does not have a water-repellent group). A preferred hydrolyzable metal compound that does not have a water-repellent group is a hydrolyzable silicon compound that does not have a water-repellent group. The hydrolyzable silicon compound that does not have a water-repellent group is, for example, at least one silicon compound (that does not have a water-repellent group) selected from silicon alkoxide, chlorosilane, acetoxysilane, alkenyloxysilane, and aminosilane, and silicon alkoxide that does not have a water-repellent group is preferred. An example of an alkenyloxysilane is isopropenoxysilane.

[0081] The hydrolyzable silicon compound having no water-repellent group may be a compound represented by the following formula (III). SiY4(III) As described above, Y is a hydrolyzable functional group, and is preferably at least one selected from an alkoxyl group, an acetoxy group, an alkenyloxy group, an amino group, and a halogen atom.

[0082] The hydrolyzable metal compound without a water-repellent group is hydrolyzed or partially hydrolyzed, and at least a portion of the hydrolyzed metal compound undergoes polycondensation to provide a metal oxide component in which a metal atom is bonded to an oxygen atom. This component firmly bonds the metal oxide fine particles to the water-absorbent resin, and can contribute to improving the abrasion resistance, hardness, water resistance, etc. of the anti-fogging layer. The metal oxide component derived from the hydrolyzable metal compound without a water-repellent group is preferably in the range of 0 to 40 parts by mass, preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, particularly preferably 3 to 10 parts by mass, and in some cases 4 to 12 parts by mass, per 100 parts by mass of the water-absorbent resin.

[0083] A preferred example of a hydrolyzable silicon compound having no water-repellent group is a tetraalkoxysilane, more specifically a tetraalkoxysilane having an alkoxy group having 1 to 4 carbon atoms. The tetraalkoxysilane is, for example, at least one selected from tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxysilane, tetra-sec-butoxysilane, and tetra-tert-butoxysilane.

[0084] If the content of the metal oxide (silica) component derived from tetraalkoxysilane is too high, the anti-fogging properties of the anti-fogging layer may be reduced. One reason for this is that the flexibility of the anti-fogging layer is reduced, limiting the swelling and shrinkage of the film due to absorption and release of moisture. The metal oxide component derived from tetraalkoxysilane is added in an amount of 0 to 30 parts by mass, preferably 1 to 20 parts by mass, and more preferably 3 to 10 parts by mass, per 100 parts by mass of the water-absorbing resin.

[0085] Another preferred example of a hydrolyzable silicon compound having no water-repellent group is a silane coupling agent. The silane coupling agent is a silicon compound having different reactive functional groups. Preferably, a portion of the reactive functional groups is a hydrolyzable functional group. The silane coupling agent is, for example, a silicon compound having an epoxy group and / or an amino group and a hydrolyzable functional group. Preferred examples of the silane coupling agent include glycidyloxyalkyltrialkoxysilane and aminoalkyltrialkoxysilane. In these silane coupling agents, the alkylene group directly bonded to the silicon atom preferably has 1 to 3 carbon atoms. Since glycidyloxyalkyl groups and aminoalkyl groups contain functional groups (epoxy groups, amino groups) that exhibit hydrophilicity, they are not water-repellent as a whole, despite containing alkylene groups.

[0086] Silane coupling agents firmly bond the water-absorbent resin, which is an organic component, with inorganic components such as metal oxide particles, and can contribute to improving the abrasion resistance, hardness, and water resistance of the anti-fogging layer. However, if the content of the metal oxide (silica) component derived from the silane coupling agent is excessive, the anti-fogging properties of the anti-fogging layer will decrease and, in some cases, the anti-fogging layer will become cloudy. The metal oxide component derived from the silane coupling agent is added in an amount of 0 to 10 parts by mass, preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 2 parts by mass, per 100 parts by mass of the water-absorbent resin.

[0087] (Crosslinked structure) The anti-fogging layer may contain a crosslinked structure derived from a crosslinking agent, preferably at least one crosslinking agent selected from an organoboron compound, an organotitanium compound, and an organozirconium compound. The introduction of a crosslinked structure improves the abrasion resistance, scratch resistance, and water resistance of the anti-fogging layer. From another perspective, the introduction of a crosslinked structure facilitates improving the durability of the anti-fogging layer without reducing its anti-fogging performance.

[0088] When a crosslinked structure derived from a crosslinking agent is introduced into an anti-fogging layer whose metal oxide component is a silica component, the anti-fogging layer may contain, as a metal atom, silicon as well as a metal atom other than silicon, preferably boron, titanium, or zirconium.

[0089] The type of crosslinking agent is not particularly limited as long as it can crosslink the water-absorbent resin used. Here, only examples of organic titanium compounds are given. The organic titanium compound is, for example, at least one selected from titanium alkoxides, titanium chelate compounds, and titanium acylates. Examples of titanium alkoxides include titanium tetraisopropoxide, titanium tetra-n-butoxide, and titanium tetraoctoxide. Examples of titanium chelate compounds include titanium acetylacetonate, titanium ethyl acetoacetate, titanium octylene glycol, titanium triethanolamine, and titanium lactate. Titanium lactate may be an ammonium salt (ammonium titanium lactate). Examples of titanium acylates include titanium stearate. A preferred organic titanium compound is a titanium chelate compound, particularly titanium lactate.

[0090] When the water-absorbing resin is polyvinyl acetal, the preferred crosslinking agent is an organic titanium compound, particularly titanium lactate.

[0091] (Other optional ingredients) The anti-fogging layer may contain other additives. Examples of the additives include glycols such as glycerin and ethylene glycol, which have the function of improving anti-fogging properties. The additives may also be surfactants, leveling agents, ultraviolet absorbers, colorants, antifoaming agents, preservatives, etc.

[0092] (base layer) The anti-fogging layer can be laminated directly on each functional layer 3, 4, or an underlayer can be formed on each functional layer 3, 4, and then the anti-fogging layer can be laminated on top of the underlayer. By laminating the anti-fogging layer on each functional layer 3, 4 via the underlayer in this way, the anti-fogging layer can be made less likely to peel off. For example, a silane coupling agent or the like can be used for the underlayer.

[0093] Thickness The thickness of the organic-inorganic composite anti-fogging layer may be adjusted as appropriate depending on the required anti-fogging properties and other factors. The thickness of the organic-inorganic composite anti-fogging layer is preferably 1 to 20 μm, more preferably 2 to 15 μm, even more preferably 2 to 12 μm, and particularly preferably 3 to 10 μm. If the thickness of the anti-fogging layer is 1 μm or more, a sufficient anti-fogging effect can be obtained. On the other hand, if the anti-fogging layer is too thick, the reflected image may be distorted due to unevenness in the film thickness. Furthermore, since the anti-fogging layer is formed from a resin material as described above and has birefringence, if it is too thick, the image may become blurred.

[0094] <3-2. Method for forming anti-fogging layer> The method for forming the anti-fogging layer having the above-mentioned composition is not particularly limited, but for example, the layer can be formed by the following method.

[0095] First, the coating liquid for the organic-inorganic composite anti-fogging layer (anti-fogging layer solution) is prepared. Next, the coating liquid is applied to the substrate 1 using a coater, and then dried in a first heating furnace.

[0096] When applying the coating liquid, it is preferable to maintain the relative humidity of the atmosphere at less than 60%, and more preferably at 40% or less. Maintaining a low relative humidity can prevent the organic-inorganic composite anti-fogging layer from absorbing excessive moisture from the atmosphere. If a large amount of moisture is absorbed from the atmosphere, the remaining water may penetrate into the matrix of the organic-inorganic composite anti-fogging layer and reduce the strength of the film.

[0097] In the first heating furnace, heating is preferably carried out at 200°C or less, for example, 50 to 150°C. The heating time is preferably 1 to 20 minutes, and more preferably 2 to 10 minutes. This heating can also be carried out multiple times. For example, heating can be carried out for 3 to 5 minutes twice or more. In this way, the coating liquid is baked, and a crosslinked structure between the water-absorbent resin and Si is formed. However, this is not a strong crosslinked structure formed by completely baking the coating liquid, but rather a provisionally formed anti-fogging layer.

[0098] Next, the substrate dried as described above is immersed in a water tank. This causes the anti-fogging layer to swell on the substrate 1, cleaving some of the crosslinking points. Furthermore, impurities contained in the water-absorbent resin, such as Na and Cl, are removed. Furthermore, uncrosslinked water-absorbent resin composition is also removed. The water stored in the water tank can be, for example, at 10 to 80°C, more preferably 20 to 60°C, and particularly preferably 25 to 50°C. The water temperature may be less than 10°C, but if it is lower than 10°C, the effect of removing alkaline components may be reduced. On the other hand, if it is higher than 80°C, a large amount of water vapor will evaporate from the water tank, which may increase the burden on the equipment and working environment. From the above perspectives, in order to maintain a relatively high alkaline component removal effect while reducing the burden on the equipment and working environment, it is particularly preferable that the water temperature be 25 to 50°C. Furthermore, the immersion time in the water tank can be, for example, 1 to 30 minutes, more preferably 3 to 20 minutes, and particularly preferably 3 to 10 minutes. Even when the water temperature is low and the efficiency of removing alkaline components is low as described above, the alkaline components can be removed to a sufficient extent by extending the immersion time. However, a long immersion time reduces production efficiency, so an immersion time of 3 to 10 minutes is particularly preferable. For example, the product can be immersed in water at 25 to 50°C for about 3 to 10 minutes. This water treatment can also be performed multiple times. By performing the water treatment multiple times in this way, the effects described below can be obtained even in a small water tank without enlarging the tank.

[0099] Next, the substrate 1 is heated in a second heating furnace. In this second heating furnace, the swollen anti-fogging layer is baked, and the cross-linked structure of the water-absorbent resin and Si remaining in the anti-fogging layer is strengthened. The heating temperature in this heating furnace is preferably 200°C or less, for example, 50 to 150°C, as in the first heating furnace described above. The heating time is longer than in the first heating furnace, for example, preferably 3 to 60 minutes, and more preferably 5 to 30 minutes. In this way, the anti-fogging layer is sufficiently baked, and the anti-fogging layer is completed.

[0100] <3-3. Anti-fogging layer with hydrophilic layer> The anti-fogging layer described above mainly has a moisture absorbing function, but a hydrophilic layer can be further formed on this anti-fogging layer (moisture absorbing layer), as will be explained in detail below.

[0101] This hydrophilic layer can have various configurations, but for example, it can contain polyether-modified dimethylsiloxane represented by the following formula (A). [ka] However, m, n, x, and y are independently integers of 1 or more, R 1 is a hydrogen atom or a methyl group, R 2 is an alkyl group having 1 to 3 carbon atoms.

[0102] Furthermore, the above formula (A) can be further configured as follows. (1) The average molecular weight of the polyether-modified dimethylsiloxane can be set to 3,000 to 300,000. (2) m can be an integer of 2 or 3. In other words, the connection between the silicone main chain, its side chain, and the polyether side chain is an ethylene group or a propylene group. Such polyether-modified dimethylsiloxane can be obtained by addition reaction of dimethylpolysiloxane, in which some of the methyl groups in the dimethylpolysiloxane main chain have been replaced with hydrogen atoms, with polyether having vinyl groups at the terminals. (3) The degree of polymerization n of the polyether side chain can be an integer of 3 to 600. In other words, the molecular weight of polyethylene glycol is about 200 to 20,000 (degree of polymerization is about 4 to 400). (4) The modification ratio, y / (x+y), can be 0.01 or more and less than 1. In other words, at least one out of 100 siloxane units can be modified, and all (except for both ends) can be modified.

[0103] The hydrophilic layer can be formed by any conventional method. For example, polyether-modified dimethylsiloxane, either as is or diluted with a solvent capable of dissolving it, can be impregnated into a cotton cloth and then rubbed onto the anti-fogging layer with the cotton cloth. Alternatively, the diluted solution can be applied to the anti-fogging layer by spray coating, flow coating, or the like, and the solvent can be evaporated to dryness.

[0104] The formation of such a hydrophilic layer can provide the following effects. For example, when the moisture absorption of the hygroscopic anti-fogging layer progresses and the layer becomes saturated, water vapor adheres to the hydrophilic layer, but the hydrophilic function of the layer causes a water film to form on the surface of the hydrophilic layer. Therefore, even though a water film is formed after the anti-fogging layer becomes saturated, the occurrence of fogging due to water droplets can be suppressed.

[0105] <3-4. Other aspects of the anti-fogging layer> In the above example, the anti-fog layer is laminated directly on the substrate 1, but an anti-fog sheet can also be attached. The anti-fog sheet includes a transparent substrate film in sheet form, the anti-fog layer laminated on one side of the substrate film, and a transparent adhesive layer laminated on the other side of the substrate film. The adhesive layer can then be fixed to the first main surface 11 of the substrate 1, thereby fixing the anti-fog sheet.

[0106] The substrate film can be formed of a transparent resin sheet such as polyethylene, polyethylene terephthalate, etc. The thickness of the substrate film can be set to, for example, 75 to 100 μm. The adhesive layer can be formed of, for example, an acrylic or silicone adhesive layer.

[0107] It is also possible to eliminate the use of a substrate film. First, a release film is prepared, and an anti-fog layer and an adhesive layer are laminated in this order on this release film. Thereafter, the adhesive layer is attached to the first main surface 11 of the substrate 1, and then the release film is removed, leaving the adhesive layer and the anti-fog layer laminated in this order on the substrate 1. Therefore, in this embodiment, a substrate film is not necessary, and distortion caused by the substrate film can be eliminated. It is also possible to attach a protective film to the adhesive layer, and then, when using, remove this protective film and then attach the adhesive layer to the substrate.

[0108] <3-5. Surface roughness> The surface roughness Ra of the anti-fogging layer can be, for example, 10 to 1000 nm. By making the surface roughness 10 nm or more, an anti-reflection effect can be obtained. The anti-reflection effect is particularly large in the visible light band with a light wavelength of 400 to 800 nm. However, a surface roughness Ra greater than 1000 nm is not preferable because it may cause light scattering.

[0109] <4. Drone> The cover member described above is used in a radio-controlled aircraft, i.e., a drone. FIG. 2 is a schematic side view of the drone. As shown in FIG. 2, the drone includes a main body 91 extending in the front-rear direction, an imaging device 5 attached to the tip of a support member 92 extending downward from the front of the main body 91, two legs 93 attached to each of the left and right sides of the main body, and a propeller 4 attached to the upper end of each leg 93. The main body 91 houses a drive source for the propeller 4, a control device for flight and other operations, a communication device, and the like. The imaging device 5 is provided with a lens 51, and a cover member 10 is attached in front of the lens. The cover member 10 is provided with a bracket 6 for attaching to the lens 51. The cover member 10 and the bracket 6 form a closed space in front of the lens 51. In this case, the first main surface 11 of the base material 1 of the cover member 10 faces this closed space. Therefore, since the first functional layer 2 is laminated on the first main surface 11, fogging of the first main surface 11 due to the temperature difference or air pressure difference between the enclosed space and the outside can be suppressed. In particular, drones often fly while repeatedly ascending and descending, which can cause significant changes in temperature and air pressure as described above. As a result, fogging is likely to occur on the cover member 10. Therefore, if the cover member of this embodiment is used as a cover member for an imaging device mounted on a drone, it is possible to prevent fogging from interfering with imaging.

[0110] 2 is an example, and can be used for all known drones to which an imaging device can be attached. For example, some drones are capable of moving underwater, and the cover member according to this embodiment can also be used for such drones. That is, even when moving underwater, significant changes in temperature and air pressure can occur, so the cover member can be suitably used.

[0111] <5.Other> In the above example, the first main surface 11 of the substrate 1 faces the camera lens side of the imaging device, so the second main surface 12 is exposed to the outside air. Therefore, to prevent water droplets from adhering to the second main surface 12, for example, a water-repellent layer or a hydrophilic layer (third functional layer) can be formed on the second main surface 12. The water-repellent layer and the hydrophilic layer can be formed by coating a known water-repellent film or a hydrophilic film. This also applies to the second embodiment described later.

[0112] [Example]

[0113] Examples of the first embodiment will be described below, but the present invention is not limited to the following examples.

[0114] As Example 1, the following cover member was produced. (1) Base material: Float glass with a thickness of 1.1 mm was used. (2) First functional layer: The anti-fogging layer shown below was formed on the first main surface of the substrate.

[0115] (i) Preparation of coating solution for anti-fog layer A coating solution for forming an anti-fog layer was prepared by placing 62.5% by mass of a polyvinyl acetal resin-containing solution (Sekisui Chemical Co., Ltd.'s "S-LEC KX-5," solids content 8% by mass, degree of acetalization 9 mol%, containing an acetal structure derived from benzaldehyde), 0.37% by mass of n-hexyltrimethoxysilane (HTMS, Shin-Etsu Chemical Co., Ltd.'s "KBM-3063"), 1.04% by mass of tetraethoxysilane (TEOS, Shin-Etsu Chemical Co., Ltd.'s "KBE-04"), 20.44% by mass of an alcohol solvent (Nippon Alcohol Industry Co., Ltd.'s "Solmix AP-7"), 15.63% by mass of purified water, 0.01% by mass of hydrochloric acid as an acid catalyst, and 0.01% by mass of a leveling agent (Shin-Etsu Chemical Co., Ltd.'s "KP-341") in a glass container and stirring at room temperature (25°C) for 3 hours.

[0116] (ii) Anti-fogging layer deposition process First, the anti-fogging layer coating solution prepared as described above was applied to the substrate and passed through a heating furnace at 90°C for 5 minutes. Next, this substrate was immersed in water at 50°C for 10 minutes and heated in a heating furnace at 110°C for 10 minutes. Thus, the moisture absorption layer of the anti-fogging layer was formed.

[0117] Next, polyether-modified dimethylsiloxane (BYK-333 manufactured by BYK Chemie Japan Co., Ltd.) was diluted to 1 wt% with an alcohol mixed solvent ("Solmix AP-7" manufactured by Nippon Alcohol Sales Co., Ltd.) to prepare a coating solution, and the entire water supply film of the tilted substrate was coated by the flow coating method so as to be wetted and then dried as it was. Thus, the hydrophilic layer was formed. The film thickness of the hydrophilic layer was 10 nm.

[0118] <B. Second Embodiment> Hereinafter, a second embodiment when the transparent laminate according to the present invention is applied to a cover member will be described while referring to the drawings. FIG. 3 is a cross-sectional view of the cover member according to the second embodiment.

[0119] The cover member 20 according to the present embodiment is different from the first embodiment in that a second functional layer 3 is further laminated on the above-described first functional layer 2, and other configurations are as described in the first embodiment. Hereinafter, the second functional layer will be described.

[0120] <1. Outline of the Cover Member> As shown in FIG. 3, the cover member member member 20 according to the present embodiment includes a substrate 1, a first functional layer 2 laminated on the first main surface 11 of the substrate 1, and a second functional layer 3 laminated on the first functional layer 2. The substrate 1 and the first functional layer 2 are the same as those shown in the first embodiment.

[0121] As the second functional layer 3, for example, an antireflection film, an antiglare film, an antistatic film, an antibacterial film, etc. can be adopted. Hereinafter, an example in which an anti-fogging layer is adopted as the first functional layer 2 and an antireflection layer is adopted as the second functional layer 3 will be described.

[0122] The anti-fogging layer of the first functional layer 2 does not have a hydrophilic layer on the top surface as in the first embodiment, but is, for example, a moisture-absorbing layer formed of an organic-inorganic composite anti-fogging layer. If an anti-reflection layer is laminated on such a moisture-absorbing anti-fogging layer, the moisture absorption effect may be impaired. Therefore, the anti-reflection layer according to this embodiment has voids inside, thereby forming a path for water vapor to reach the anti-fogging layer 2. This will be explained in detail below.

[0123] <2.Second functional layer> FIG. 4 is a cross-sectional view of the second functional layer 3. As shown in FIG. 4, the second functional layer 3 includes hollow particles 31 and a binder 32. The hollow particles 31 are made of a material having a refractive index of 1.15 to 2.70. The binder 32 is formed of at least polysilsesquioxane and binds the hollow particles 31 together. In the second functional layer 3, the absorbances attributable to hydrocarbon groups not directly bonded to silicon atoms, the absorbance attributable to bonds between silicon atoms and non-reactive functional groups, and the absorbance attributable to bonds between silicon atoms and hydroxyl groups, as determined by attenuated total reflectance (ATR) using a Fourier transform infrared spectrophotometer, are denoted as Ia, Ib, and Ic, respectively. The second functional layer 3 satisfies at least one of the conditions Ib / Ia≧0.7 and Ib / Ic≧0.3. In this specification, Ib / Ia is also referred to as the organic / inorganic parameter (D), and Ib / Ic is also referred to as the hydrophobic parameter (H). The absorbance Ia, absorbance Ib, and absorbance Ic can be determined, for example, from an absorption spectrum obtained by the ATR method according to the method described in the Examples.

[0124] The organic-inorganic parameter (D) increases as the amount of hydrocarbon groups not directly bonded to silicon atoms contained in the binder 32 decreases. When the amount of hydrocarbon groups not directly bonded to silicon atoms contained in the binder 32 is small, the Si-O-Si network in the binder 32 is dense and the density of the inorganic component in the binder 32 increases. This allows the hollow particles 31 to be firmly fixed by the Si-O-Si network. Therefore, if Ib / Ia≧0.7 in the second functional layer 3, the hollow particles 31 are firmly fixed in the second functional layer 3, and the second functional layer 3 has properties advantageous for low refractive index coating. If the hollow particles are not sufficiently fixed in the film, the mechanical strength of the film may decrease.

[0125] The hydrophobic parameter (H) increases as the number of hydroxy groups bonded to silicon atoms in the binder 32 decreases. For example, if hydroxy groups condense with each other in the raw material of the binder 32 to form a network of Si-O-Si, the number of hydroxy groups bonded to silicon atoms in the binder 32 decreases. If the hydrophobic parameter (H) is equal to or greater than a predetermined value, a dense network of Si-O-Si is formed in the binder 32, and this network can firmly fix the hollow particles 31. Therefore, if Ib / Ic≧0.3 in the second functional layer 3, the hollow particles 31 are firmly fixed in the second functional layer 3, and the second functional layer 3 has properties advantageous for low refractive index coating.

[0126] Preferably, the second functional layer 3 further satisfies the conditions Ib / Ia≧0.7 and Ib / Ic≧0.3, which allows the hollow particles 31 to be more reliably and firmly fixed in the second functional layer 3, and gives the second functional layer 3 advantageous properties for low refractive index coating.

[0127] When silanol groups (Si-OH) are present in the binder 32, the silanol groups form hydrogen bonds with the silanol groups present on the surface of the glass plate 1, resulting in high affinity. Therefore, a film having a hydrophobicity parameter (H) of a predetermined value or less also easily adheres to the glass plate 1. To exhibit good adhesion to both substrates having hydrophilic and hydrophobic surfaces, the second functional layer 3 more preferably satisfies the condition 0.3≦Ib / Ic≦2.0.

[0128] In the second functional layer 3, the first absorbance, second absorbance, and third absorbance, determined by ATR spectroscopy and resulting from the bond between one oxygen atom and two silicon atoms, are denoted as Id, Ie, and If, respectively. The first absorbance Id corresponds to a first wavenumber. The second absorbance Ie corresponds to a second wavenumber greater than the first wavenumber. The third absorbance If corresponds to a third wavenumber greater than the second wavenumber. The second functional layer 3 preferably satisfies at least one of the following conditions: Id / Ib≦60, Ie / Ib≦20, and If / Ib≦174. In this specification, Id / Ib is also referred to as the first network parameter (N1), Ie / Ib is also referred to as the second network parameter (N2), and If / Ib is also referred to as the third network parameter (N3).

[0129] The first wave number is, for example, 455±50 cm -1 The second wavenumber is the wavenumber at which the maximum value of the absorption spectrum appears. -1 The third wavenumber is the wavenumber at which the maximum value of the absorption spectrum appears. -1 This is the wavenumber at which the maximum value of the absorption spectrum appears.

[0130] The first network parameter (N1), the second network parameter (N2), and the third network parameter (N3) increase as the number of bonds between oxygen atoms and two silicon atoms (Si-O-Si) in the binder 32 increases. The more developed the Si-O-Si network formed by condensation of hydroxyl groups in the raw materials of the binder 32, the larger the first network parameter (N1), the second network parameter (N2), and the third network parameter (N3). Meanwhile, to maintain good film formability, it is important to suppress the aggregation of hollow particles and maintain a uniform coating thickness. To suppress the aggregation of hollow particles, it is desirable to prevent excessive development of the Si-O-Si network. From this perspective, it is desirable for the second functional layer 3 to satisfy at least one of the following: N1 is 60 or less, N2 is 20 or less, and N3 is 174 or less. This allows the second functional layer 3 to be formed well, and the second functional layer 3 can provide an antireflection structure with good antireflection performance.

[0131] More preferably, the second functional layer 3 further satisfies the conditions Id / Ib≦60, Ie / Ib≦20, and If / Ib≦174.

[0132] Typically, the polysilsesquioxane of the binder 32 has a non-reactive functional group bonded to a silicon atom. In order for the polysilsesquioxane of the binder 32 to exhibit an appropriate hydrophobic effect, the non-reactive functional group is a hydrophobic functional group, such as an alkyl group. Desirably, the polysilsesquioxane of the binder 32 is a polysilsesquioxane in which a hydrocarbon group containing 16 or fewer carbon atoms is bonded to a silicon atom as a non-reactive functional group. In this case, since the non-reactive functional group is not bulky, a dense Si-O-Si network is easily formed.

[0133] The binder 32 may further contain silica, for example. In this case, the polysilsesquioxane contained in the binder 32 tends to exert a hydrophobic effect, while the silica contained in the binder 32 tends to exert a hydrophilic effect. Therefore, by adjusting the ratio (Mp / Ms) of the amount of substance Mp of polysilsesquioxane to the amount of substance Ms of silica in the binder 32, the hydrophilicity or hydrophobicity of the second functional layer 3 can be adjusted to an appropriate level. This allows the second functional layer 3 to be appropriately formed on a substrate having a hydrophilic surface, such as a glass substrate, and also on a substrate having a hydrophobic surface, such as a resin substrate. From this perspective, the ratio (Mp / Ms) of the amount of substance Mp of polysilsesquioxane to the amount of substance Ms of silica in the binder 32 is, for example, 3 / 7 or more, preferably 1 to 9, and more preferably 3 / 2 to 4.

[0134] The hollow particles 31 are not particularly limited as long as they have a hollow structure, and may have, for example, a spherical, cylindrical, or sheet-like shape. The hollow particles 31 have, for example, an average particle diameter (primary particle diameter) of 10 to 150 nm. This makes it easy for the hollow particles 31 to be uniformly dispersed in the second functional layer 3. The average particle diameter of the hollow particles 31 can be determined, for example, by arithmetically averaging the particle diameters of 50 or more hollow particles 31 observed using a transmission electron microscope (TEM) or a scanning electron microscope (SEM). Note that the particle diameter of each particle means the maximum diameter.

[0135] The hollow particles 31 preferably have an average particle diameter of 20 to 100 nm, more preferably 30 to 70 nm. The maximum dimension of the internal space in the hollow particles 31 is, for example, 5 to 100 nm, preferably 10 to 70 nm, more preferably 20 to 50 nm. The hollow particles 31 are preferably monodisperse particles having a coefficient of variation of 0.1 or less.

[0136] The material of the hollow particles 31 may be an inorganic material or an organic material as long as it has a refractive index of 1.15 to 2.70. The material of the hollow particles 31 is preferably a material having a refractive index of 1.20 to 2.00, more preferably a material having a refractive index of 1.30 to 1.50, and even more preferably a material having a refractive index of 1.38 to 1.46. From the viewpoint of resistance to deformation due to external forces, the hollow particles 31 are preferably made of an inorganic material. In this case, the hollow particles 31 are made of, for example, at least one material selected from the group consisting of silica, magnesium fluoride, alumina, aluminosilicate, titania, and zirconia.

[0137] In particular, the hollow particles 31 are preferably made of silica or magnesium fluoride in order to provide an antireflection structure with high antireflection performance by a low refractive index coating using the second functional layer 3. The refractive index of silica is 1.46, and the refractive index of magnesium fluoride is 1.38.

[0138] The structure and material of the hollow particles 31 are determined so that the hollow particles 31 have a desired refractive index. For example, the material of the hollow particles 31 and the ratio of the internal space to the total volume of the hollow particles 31 are determined so that the hollow particles 31 have a desired refractive index. The hollow particles 31 have a refractive index of, for example, 1.10 to 1.40, preferably 1.20 to 1.35, and more preferably 1.25 to 1.30. For example, when multiple types of hollow particles made of materials with different refractive indexes have the same ratio of the internal space to the total volume of the hollow particles, hollow particles made of a material with a low refractive index have a lower refractive index than hollow particles made of a material with a high refractive index.

[0139] The refractive index of the hollow particles 31 can be measured, for example, by the immersion method (Becke line method). For example, if the hollow particles 31 are made of silica, the refractive index of the hollow particles 31 can be measured according to the following procedure: (i) The dispersion medium of the dispersion liquid of the hollow particles 31 is evaporated and dried to obtain a powder. (ii) The powder obtained in (i) is mixed with various standard refractive index liquids having different refractive indices, such as Series A and Series AA manufactured by Gargill. (iii) When the mixed liquid obtained in (ii) becomes transparent, the refractive index of the standard refractive index liquid used is determined as the refractive index of the hollow particles 31.

[0140] The hollow particles 31 may be commercially available or may be prepared by a predetermined method. For example, the hollow particles 31 may be prepared by forming a shell around a core and then removing the core. For example, a shell made of silica or a shell made of magnesium fluoride may be formed around a polymer core having a particle diameter of several tens of nanometers. The polymer core may then be removed by dissolving in a solvent or by combustion to obtain hollow particles 31 that are hollow silica particles or hollow magnesium fluoride particles. Alternatively, hollow particles 31 that are hollow magnesium fluoride particles may be obtained by forming a shell made of magnesium fluoride around a silica core and then dissolving the silica core with an alkali.

[0141] In the second functional layer 3, the ratio (Wh / Wb) of the mass of the hollow particles 31 to the mass of the binder 32, Wb, is, for example, 1 / 5 to 20, preferably 1 / 3 to 10, and more preferably 1 to 5. This makes it possible to provide an antireflection structure with high antireflection performance by using the second functional layer 3 as a low refractive index coating.

[0142] The thickness of the second functional layer 3 is not particularly limited, but is determined, for example, according to the wavelength of light whose reflection should be prevented. Specifically, the thickness of the second functional layer 3 is set so that the optical film thickness (refractive index × physical film thickness) satisfies λ / 4, where λ (nm) is the central wavelength of the wavelengths whose reflection should be prevented. For example, to prevent reflection of light in the visible light range (practically, wavelengths of 380 nm to 780 nm), if the central wavelength λ is λ = 550 nm and the refractive index of the low-refractive index film used is 1.20, the optimal physical film thickness is 115 nm. The practically effective thickness of the second functional layer 3 for preventing reflection of visible light is 50 to 300 nm, preferably 70 to 200 nm, and more preferably 90 to 170 nm. This allows for the provision of an anti-reflection structure with high anti-reflection performance through the low-refractive index coating using the second functional layer 3. Furthermore, to prevent reflection of light with a central wavelength of λ=850 nm, which is close to the visible light region in the near-infrared region (e.g., wavelengths of 800 nm to 2500 nm), the optimal physical film thickness is 177 nm when the refractive index of the low-refractive-index film used is 1.20. The practically effective thickness of the second functional layer 3 for preventing reflection of near-infrared light is 80 to 350 nm, preferably 130 to 250 nm, and more preferably 150 to 220 nm. This allows the low-refractive-index coating using the second functional layer 3 to provide an anti-reflection structure with high anti-reflection performance. When a multilayer film is used as the anti-reflection structure, a low-refractive-index layer with a thickness of 50 nm or less may be used. The physical film thickness of the low-refractive-index film is not limited to these, but its cross section can be measured using a SEM, TEM, ellipsometer, or the like.

[0143] The second functional layer 3 has a refractive index of, for example, 1.45 or less, preferably 1.1 to 1.35. This allows for a low-refractive-index coating using the second functional layer 3 to provide an antireflection structure with high antireflection performance. The second functional layer 3 preferably has a refractive index of 1.30 or less, more preferably 1.25 or less. To reduce the refractive index of the second functional layer 3, the second functional layer 3 may contain air spaces between the hollow particles 31 or within the binder 32. The refractive index of the second functional layer 3 can be determined, for example, by reflectance spectroscopy. Increasing the proportion of this air space (void fraction) can reduce the refractive index of the second functional layer 3. The void fraction is, for example, 0 to 70%, preferably 10 to 50%, and more preferably 20 to 50%. This also applies to the second functional layer composed of multiple layers, as described below.

[0144] The second functional layer 3 is, for example, a cured product obtained by curing a predetermined liquid composition. This liquid composition contains hollow particles, polysilsesquioxane, and a solvent. The hollow particles are made of a material having a refractive index of 1.15 to 2.70. In the cured product obtained by applying the liquid composition to a substrate and curing the liquid composition, at least one of the conditions Ib / Ia≧0.7 and Ib / Ic≧0.3 is satisfied. The solvent contained in the liquid composition is, for example, an alcohol such as ethanol, or water.

[0145] Since this liquid composition does not require an organosilane compound having a fluoroalkyl group, phase separation is unlikely to occur in the liquid composition, and the liquid composition is likely to be uniform. Furthermore, the liquid composition has high wettability with respect to the substrate and the resin substrate, and the liquid composition easily provides an antireflection layer with a uniform structure.

[0146] In the above cured product, it is desirable that the conditions Ib / Ia≧0.7 and Ib / Ic≧0.3 be further satisfied.

[0147] In the above cured product, it is desirable that at least one of the following conditions be satisfied: Id / Ib≦60, Ie / Ib≦20, and If / Ib≦174.

[0148] More preferably, the above cured product further satisfies the conditions Id / Ib≦60, Ie / Ib≦20, and If / Ib≦174.

[0149] The polysilsesquioxane in the liquid composition is, for example, a polysilsesquioxane in which a hydrocarbon group containing 16 or fewer carbon atoms is bonded to a silicon atom as a non-reactive functional group.

[0150] The characteristics of the hollow particles 31 in the second functional layer 3 typically also apply to the hollow particles in the liquid composition. Therefore, the hollow particles in the liquid composition have an average particle size (primary particle size) of, for example, 10 to 150 nm. Furthermore, the hollow particles in the liquid composition are preferably made of at least one selected from the group consisting of silica, magnesium fluoride, alumina, aluminosilicate, titania, and zirconia.

[0151] The liquid composition may contain, for example, silica in addition to the hollow particles.

[0152] The second functional layer 3 is formed, for example, by applying a liquid composition to the first functional layer 2 and curing the liquid composition. In this way, a low refractive index layer is formed using the second functional layer 3. By using a liquid composition, an organosilane compound having a fluoroalkyl group is not required, and a low refractive index coating can be easily achieved.

[0153] The polysilsesquioxane in the liquid composition is formed, for example, by hydrolysis and dehydration condensation of a trifunctional alkoxysilane contained in the raw material of the liquid composition. Furthermore, when silica is contained in the liquid composition in addition to the hollow particles, this silica is formed, for example, by hydrolysis and dehydration condensation of a tetrafunctional alkoxysilane contained in the raw material of the liquid composition. For example, the tetrafunctional alkoxysilane forms silica (SiO2) by the reactions of the following (Equation 1) and (Equation 2). R a represents an alkyl group. Trifunctional alkoxysilanes can be converted into polysilsesquioxanes (R b SiO 3 / 2 ) is formed. R b indicates a non-reactive functional group, and R c represents an alkyl group. Si(OR a )4+4H2O→Si(OH)4+4R a OH (Formula 1) Si(OH)4→SiO2+2H2O (Formula 2) R b Si(OR c )3+3H2O→R b Si(OH)3+3R c OH (Formula 3) R b Si(OH)3→R b SiO 3 / 2 +3 / 2H2O (Formula 4)

[0154] The hydrolysis catalyst contained in the raw material of the liquid composition is, for example, a carboxylic acid such as formic acid or acetic acid.

[0155] <3. Adjustment of refractive index> In order for the second functional layer 3 to function properly as an anti-reflection layer, the refractive index of the second functional layer 3 must be determined taking into account the refractive index of the anti-fogging layer, which is the first functional layer 2. The refractive index of the anti-fogging layer is generally 1.5 to 1.6, depending on the material. It is known that in order to reduce the refractive index of the first functional layer 2 and the second functional layer 3 as a whole, the refractive index of the second functional layer 3 should be set to the half power of the refractive index of the first functional layer 1. For example, if the refractive index of the anti-fogging layer is 1.55, the refractive index of the second functional layer 3 is preferably 1.24.

[0156] As described above, the second functional layer 3 is composed of hollow particles 31, binder 32, and air layers. The hollow particles contain air, which allows the refractive index to be lowered. Furthermore, since the second functional layer 3 also contains air layers, increasing the air layer ratio (void fraction) can further reduce the refractive index. Therefore, by adjusting the hollow particle ratio and the void fraction, the refractive index of the second functional layer 3 can be adjusted to approximately ±0.1 of the refractive index of the first functional layer 2 to the power of 1 / 2.

[0157] <4. Second functional layer consisting of multiple layers> In the above example, the second functional layer 3 is formed as a single layer, but it can also be formed as two layers. For example, as shown in FIG. 5, the second functional layer 3 can be composed of a first layer 301 laminated on the first functional layer 2 and a second layer 302 laminated on the first layer 301. To reduce the refractive index of the functional layers 2 and 3 as a whole, the refractive index of the first layer 301 is made smaller than that of the anti-fogging layer 2, and the refractive index of the second layer 302 is also made smaller than that of the first layer 301. The refractive index of the first layer 301 can be, for example, 1.35 to 1.45, and the refractive index of the second layer 302 can be, for example, 1.10 to 1.25.

[0158] In one such example, the second layer 302 is formed from the single-layer second functional layer 3 described above. The first layer 301 is the second layer 302 minus the hollow particles 31, and is a layer made of at least one of polysilsesquioxane and silica, which constitute the binder. The thickness of this second layer 302 can be, for example, 30 to 300 nm. Although the first layer 301 does not contain hollow particles or an air layer, the binder 32 is porous and therefore allows water vapor to pass through. Therefore, even when such a first layer 301 is formed, water vapor reaches the anti-fogging layer 2 via the first layer 301 and the second layer 302. However, because water vapor is less likely to pass through the first layer 301 than the second layer 302, the first layer 301 is preferably thinner than the second layer 302.

[0159] In this way, when the second functional layer 3 is formed of multiple layers, the refractive index of each layer can be gradually decreased from the first functional layer 2 toward the outermost layer, so the second functional layer 3 can be formed of three or more layers.

[0160] <5. Physical properties of the second functional layer> When the first functional layer 2 is an anti-fogging layer, its volume may change due to moisture absorption. Since the second functional layer 3 is laminated on the first functional layer 2, it is preferable that the second functional layer 3 follow the volumetric changes of the first functional layer 2. Insufficient follow-up may result in cracks in the second functional layer 3. Therefore, for example, if the anti-fogging layer 2 has a flexural modulus of 2 to 3 GPa, the second functional layer 3 preferably has a flexural modulus that overlaps with that of the anti-fogging layer 2, for example, a range of 1 to 10 GPa, and more preferably 1 to 4 GPa. In other words, polysilsesquioxane (flexural modulus of 2 to 3 GPa) exhibiting a flexural modulus similar to that of the anti-fogging layer 2 can be suitably used as a binder for the second functional layer 3.

[0161] Furthermore, because the first and second functional layers may expand and contract due to temperature changes, it is preferable that the difference in linear expansion coefficient between the first and second functional layers be 30 ppm / °C. For example, the linear thermal expansion coefficient of the anti-fogging layer is 60 to 84 ppm / °C, while the linear thermal expansion coefficient of polysilsesquioxane is 40 to 70 ppm / °C, and therefore it can be used as a binder for the second functional layer 3. In other words, even if the film volume of the anti-fogging layer increases or decreases depending on the amount of water absorption, cracking in the first functional layer 2 and the second functional layer 3 can be suppressed.

[0162] <6. Other aspects> The first functional layer 2 and the second functional layer 3 according to this embodiment can be configured in various ways. For example, when the second functional layer 3 is a single layer, as shown in FIG. 6, an anti-fog layer 2 and an anti-reflection layer 3 can be laminated in this order on a substrate film 81, and then the substrate film 81 can be attached to the substrate 1 via an adhesive layer (not shown). Similarly, when the second functional layer 3 is a multi-layered layer, as shown in FIG. 7, an anti-fog layer 2, a first layer 301 of the anti-reflection layer, and a second layer 302 can be laminated in this order on a substrate film 81, and then the substrate film 81 can be attached to the substrate 1 via an adhesive layer 82. The substrate film 81 and the adhesive layer 82 are the same as those shown in the first embodiment.

[0163] The first functional layer 2 and the second functional layer 3 do not have to be adjacent to each other. For example, a primer layer or an absorption layer or modification layer that absorbs light of a specific wavelength may be provided between the first functional layer 2 and the second functional layer 3.

[0164] <7.Applications> Like the first embodiment, the cover member according to this embodiment can also be used as a cover member for an imaging device installed on an aircraft such as a drone. In particular, when an anti-reflection layer is formed as the second functional layer 3, it can be suitably used as a cover member for an imaging device of a drone, which often takes photographs outdoors where the environment changes. In particular, pressure changes suddenly when the drone suddenly ascends. As can be understood from Boyle's law, when pressure decreases, temperature decreases. Therefore, the transparent laminate with anti-fogging function according to the present invention can be suitably used.

[0165] [Example]

[0166] Examples 2 and 3 according to the second embodiment will be described below, but the present invention is not limited to the following examples.

[0167] As Example 2, the following cover member was produced. (1) Base material: Float glass with a thickness of 2.8 mm was used. (2) First functional layer: The anti-fogging layer shown in Example 1 of the first embodiment was formed on the first main surface of the substrate. However, this anti-fogging layer did not have a hydrophilic layer. The film thickness was 8 μm and the refractive index was 1.55. (3) Second functional layer: A single anti-reflection layer as shown below was formed.

[0168] After forming the anti-fog layer, a coating liquid for the anti-reflection layer was prepared as follows. First, 0.6 g of tetraethoxysilane (TEOS) (Tokyo Chemical Industry Co., Ltd.), 1.18 g of methyltriethoxysilane (MTES) (Tokyo Chemical Industry Co., Ltd.), 0.82 g of 0.3 wt. % formic acid (Kishida Chemical Co., Ltd.), 3 g of hollow silica particle sol (JGC Catalysts and Chemicals Co., Ltd., product name: Sururia 4110, silica solid content: approximately 25 wt. %), and 22.4 g of ethanol (Kishida Chemical Co., Ltd.) were mixed and reacted at 35°C for 3 hours. In this way, a coating liquid for the second functional layer of Example 2 was obtained. In the hollow silica particle sol, the average particle diameter of the hollow silica particles was approximately 50 nm, the thickness of the silica shell was 10 to 20 nm, the maximum dimension of the internal space of the hollow silica particles was approximately 10 to 30 nm, and the refractive index of the hollow silica particles was 1.25. The solid content of this coating liquid included 0.6 wt% silica derived from TEOS, 1.6 wt% polymethylsilsesquioxane derived from MTES, and 2.6 wt% hollow silica particles. The ratio of the amount of MTES to the amount of TEOS added in preparing the liquid composition of Example 1 was 7 / 3. The ratio of the weight of the hollow silica particles to the total weight of the solid content of the silica derived from TEOS and the polymethylsilsesquioxane derived from MTES was 1.3 / 1.1.

[0169] Next, the coating liquid was applied to the anti-fogging layer by spin coating. Immediately after application, a uniform coating film with good appearance was obtained. The coating film was then dried in an oven at 200°C for 10 minutes to obtain a cover member according to Example 2.

[0170] The anti-reflection coating had a thickness of 100 nm and a refractive index of 1.24±0.5. The volume ratio of the materials constituting the anti-reflection coating was as follows: hollow silica particles 50 vol%, binder 23 vol%, and void fraction 23 vol%.

[0171] As Example 3, the following cover member was produced. (1) Base material: Float glass with a thickness of 2.8 mm was used. (2) First functional layer: The anti-fogging layer shown in Example 1 of the first embodiment was formed on the first main surface of the substrate. However, in this anti-fogging layer, the hydrophilic layer was not formed. The film thickness was 8 μm and the refractive index was 1.55. (3) Second functional layer: Two anti-reflection layers shown below were formed.

[0172] After forming the anti-fogging layer, a coating liquid for the anti-reflection layer was prepared as follows. That is, the coating liquid for the first layer was prepared in the same manner as the coating liquid according to Example 2, except that the sol of hollow silica particles was not added. Then, this coating liquid was applied onto the anti-fogging layer by the spin coating method. Next, the coating film was dried in an oven under the conditions of 200 °C for 10 minutes to form the first layer. The refractive index of this first layer was 1.46 and the thickness was 260 nm.

[0173] Then, a coating liquid similar to the coating liquid according to Example 2 was applied onto this first layer by the spin coating method. However, a coating liquid with an increased proportion of hollow silica particles and void ratio compared to the coating liquid according to Example 2 was used. Next, this coating film was dried in an oven under the conditions of 200 °C for 10 minutes to form the second layer. The refractive index of this second layer was 1.16 and the thickness was 95 nm.

[0174] <C. Modification example> As described above, the embodiments of the present invention have been explained. However, the present invention is not limited to the above embodiments, and various modifications are possible without departing from the spirit thereof. Note that the following modification examples can be combined as appropriate.

[0175] <1> The substrate 1 may be a composite material of a resin material and a glass plate, or may be a laminated glass in which an intermediate film is sandwiched between two glass plates.

[0176] <2> Although the above-described embodiments are directed to drones as flying objects, the present invention can be applied to various types of moving objects other than conventional automobiles, airplanes, helicopters, ships, and submarines. That is, the imaging device and cover member described above can be mounted on an unmanned or manned moving object whose control method is selected from radio control, autonomous control, direct control by a human, or a combination thereof, and which is at least one of an flying object, a terrestrial moving object, a surface moving object, and an underwater moving object. [Explanation of symbols]

[0177] 1 board 11 First main surface 12 Second main surface 2 1st functional layer 3 Second functional layer 4 Third functional layer 5. Imaging device

Claims

1. A radio-controlled flying vehicle, an imaging device having a lens; a cover member that covers the lens; Equipped with The cover member is a transparent substrate having a first major surface and a second major surface; a transparent, water-repellent, water-absorbent anti-fogging layer laminated on the first main surface of the substrate and having a surface roughness Ra of 10 nm or more and 1000 nm or less; Equipped with The cover member is arranged so that the anti-fogging layer faces the lens.

2. The flying vehicle according to claim 1 , which is configured to be capable of moving underwater.

3. A cover member provided on a radio-controlled flying object equipped with an imaging device having a lens, a transparent substrate having a first major surface and a second major surface; a transparent, water-repellent, water-absorbent anti-fogging layer laminated on the first main surface of the substrate and having a surface roughness Ra of 10 nm or more and 1000 nm or less; Equipped with the cover member is attached to the imaging device so as to cover the lens, A cover member, wherein the anti-fogging layer is arranged to face the lens side.

Images