UV-absorbing coatings, UV-absorbing films, light-absorbing films, optical components, optical units, and light irradiation devices

Abstract

This invention provides an ultraviolet-absorbing coating capable of forming a thin-film coating that highly suppresses stray light generation and exhibits excellent durability. The ultraviolet-absorbing coating contains an oxide precursor of one or more transition metals selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Ce. The oxide precursor of the aforementioned transition metal is preferably a metal salt, metal acid salt, or organometallic compound selected from one or more transition metals selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Ce.

Description

[0001] This application is a divisional application of the application filed on September 30, 2016, with application number 201610874668.8, entitled "Ultraviolet Absorbing Coating, Ultraviolet Absorbing Film, Light Absorbing Film, Optical Element, Optical Unit and Light Irradiation Device". Technical Field

[0002] This invention relates to ultraviolet absorbing coatings, ultraviolet absorbing films, light-absorbing films, optical elements, optical units, and light irradiation devices. Background Technology

[0003] For optical elements such as lenses and prisms commonly used in optical instruments such as cameras and microscopes, stray light is generated because the incident light enters from the periphery of the optical element, such as the edge of the lens (the side of the lens), or is reflected from the inner surface of the edge. This stray light mixes with the original illumination light, which causes reflected light spots, ghosting, etc. in the image, thereby reducing the optical characteristics of the optical instrument.

[0004] To prevent the aforementioned stray light, it is known to coat the edges, corners, and other peripheral parts of optical elements with a black coating that has an anti-inner-surface-reflection function to form a black coating film.

[0005] As a black coating with the aforementioned function of preventing internal reflection, for example, a coating containing metal oxides such as iron oxide, carbon black, adhesive resin, phthalocyanine compound, and a dispersant and solvent containing a polymeric dispersant has been proposed (see Patent Document 1 (Japanese Patent Application Publication No. 2014-21231)).

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2014-21231 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] The black coating described in Patent Document 1 is a coating with metal oxide particles and carbon black particles as light-absorbing components. It is made by dispersing the above particles in a color carrier (adhesive resin and solvent). However, it has the following problems: not only is the dispersion treatment of the above particles laborious and difficult to prepare easily, but also after preparation, the above particles will agglomerate and settle, making them easy to become uneven, and the pot life (usable time) is short.

[0011] In addition, existing anti-reflective coatings such as the black coating described in Patent Document 1 target visible light and infrared light, and are basically used in environments with relatively low light intensity. In contrast, since there has been a recent trend of using ultraviolet light with high light intensity, stray light that is the target of absorption has also become light with high light energy and high light intensity.

[0012] When a coating film is formed on the surface of an optical element using the black coating described in Patent Document 1, although the solvent evaporates and disappears, organic components such as adhesive resin and dispersant remain. Therefore, these organic components deteriorate when ultraviolet light enters the optical element. In addition, since carbon black is also a carbon material, it is also prone to deterioration when high-intensity ultraviolet light is incident.

[0013] The light absorbed by the coating is converted into heat. When the intensity of the incident light is high, it will promote the deterioration of the adhesive resin, dispersant, etc., which will not only cause the coating to crack and peel off, but also cause the carbon black to deteriorate and fade easily.

[0014] For example, a UV-LED used as a curing light source for UV-curable resins and UV-curable inks uses an LED that emits 1W of UV light with a wavelength of 365nm by providing 3W of power to a 1mm square LED chip. In this case, the irradiation light intensity reaches 1W / mm². 2 This is equivalent to 30,000 to 50,000 times the amount of ultraviolet light contained in sunlight. Therefore, the black coating with internal anti-reflection function used in such light source devices must be resistant to strong ultraviolet radiation.

[0015] In addition, 2W of the 3W power provided by the aforementioned ultraviolet LED is converted into heat energy, causing the LED chip itself to reach a high temperature. Therefore, as a black coating with internal surface anti-reflection function, in addition to ultraviolet resistance, it is also required to be resistant to heat (temperature).

[0016] In order to solve the above-mentioned technical problems, the inventors conducted research and came up with the idea of ​​forming an ultraviolet absorbing film without organic components as the above-mentioned coating.

[0017] As a material for forming such an ultraviolet absorbing film, colored low-melting-point glass or low-melting-point glass containing inorganic pigments can be considered. However, when using these materials to form the coating, the coating thickness can be as thick as hundreds of μm, compared to the processing tolerance of optical elements such as lenses, which is about ±0.05 to 0.10 mm (50 to 100 μm). When the coating becomes too thick, it cannot be placed in a given position and is difficult to correct.

[0018] Furthermore, for low-melting-point glass, if the difference between its coefficient of thermal expansion and that of optical elements such as lenses and prisms is not controlled within a certain range, cracks will appear in the optical elements or the low-melting-point glass layer (coating), or the low-melting-point glass layer will peel off, making it difficult to continue using optical instruments with such optical elements.

[0019] The present invention was made in view of the above circumstances, and its object is to provide an ultraviolet absorbing coating capable of forming a film in a thin film state that highly suppresses stray light generation and can exhibit excellent durability, and also provides an ultraviolet absorbing film, a light absorbing film, an optical element, an optical unit and a light irradiation device.

[0020] Methods for solving problems

[0021] In order to achieve the above objectives, the inventors conducted in-depth research and found that the above technical problems can be solved by using an ultraviolet absorbing coating containing an oxide precursor of one or more transition metals selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ce. Based on this insight, the present invention was completed.

[0022] That is, the present invention provides the following technical solution:

[0023] (1) An ultraviolet absorbing coating containing an oxide precursor of one or more transition metals selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ce.

[0024] (2) The ultraviolet absorbing coating described in (1) above, wherein the oxide precursor of the transition metal is a metal salt, metal acid salt or organometallic compound selected from one or more transition metals selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ce.

[0025] (3) The ultraviolet absorbing coating described in (1) or (2) above, wherein, based on the conversion to transition metal oxides, it contains 0.5 to 20.0% by mass of the oxide precursor of the transition metal.

[0026] (4) The ultraviolet absorbing coatings described in (1) to (3) above further contain one or more of silicon oxide precursors and aluminum oxide precursors.

[0027] (5) The ultraviolet absorbing coatings described in (1) to (4) above also contain colorants.

[0028] (6) An ultraviolet absorbing film containing an oxide of one or more transition metals selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ce.

[0029] (7) The ultraviolet absorbing film described in (6) above also contains silicon oxide or aluminum oxide.

[0030] (8) The ultraviolet absorbing film described in (6) or (7) above, wherein it contains 20 to 100% by mass of the oxide of the transition metal.

[0031] (9) The ultraviolet absorbing film of any one of (6) to (8) above has a film thickness of 50 μm or less.

[0032] (10) A light-absorbing film comprising a stack, said stack being a stack of an ultraviolet-absorbing film as described in any one of (6) to (9) above and an absorbing film that absorbs at least visible light or infrared light.

[0033] (11) An optical element having on its surface an ultraviolet absorbing film as described in any one of (6) to (9) above or a light absorbing film as described in (10) above.

[0034] (12) An optical unit having the optical element described in (11) above.

[0035] (13) A light irradiation device having the optical unit described in (12) above.

[0036] The effects of the invention

[0037] According to the present invention, an ultraviolet absorbing coating capable of forming a film that highly suppresses stray light generation and exhibits excellent durability in a thin film state can be provided, as well as an ultraviolet absorbing film, a light absorbing film, an optical element, an optical unit, and a light irradiation device. Attached Figure Description

[0038] Figure 1 This is a schematic diagram illustrating an example of a conventional optical element implementation. Figure 1 (a) and a schematic diagram of an example embodiment of the optical element of the present invention ( Figure 1 (b)).

[0039] Figure 2 This is a schematic diagram illustrating an example embodiment of the optical element of the present invention.

[0040] Figure 3 This is a schematic diagram illustrating an example embodiment of the optical element of the present invention.

[0041] Figure 4 This is a schematic diagram illustrating an example embodiment of the optical element of the present invention.

[0042] Figure 5 This is a schematic diagram illustrating an example embodiment of the optical unit of the present invention.

[0043] Figure 6 This is a schematic diagram illustrating an example embodiment of the light irradiation device of the present invention.

[0044] Figure 7 This illustrates the Fe-containing sample obtained in Example 1. x O y The graph shows the transmittance curve of the substrate with the ultraviolet absorption film.

[0045] Figure 8 This is a schematic diagram illustrating an evaluation method for ultraviolet absorption.

[0046] Figure 9 This is a schematic diagram illustrating a method for evaluating the durability of ultraviolet-absorbing films.

[0047] Figure 10 This illustrates the chromium oxide (Cr) obtained in Example 2. x O y A graph showing the transmittance curve of a substrate with a SiO2-based ultraviolet absorbing film.

[0048] Figure 11 This illustrates the manganese oxide (Mn) obtained in Example 3. x O y The figure shows the transmittance curve of the substrate of the ultraviolet absorption film.

[0049] Figure 12 This illustrates the manganese oxide (Mn) obtained in Example 4. x O y A graph showing the transmittance curve of a substrate with a SiO2-based ultraviolet absorbing film.

[0050] Figure 13 This is a graph showing the transmittance curves of glass substrates after the absorber film forming coating liquids obtained in Examples 5 and 6 are applied and dried.

[0051] Figure 14 This is a graph showing the transmittance curves of glass substrates after they have been coated with the absorption film forming liquids obtained in Examples 5 and 6, dried, and then heat-treated.

[0052] Figure 15 This is a graph showing the transmittance curves of the coating liquid used to form the absorption film obtained in Examples 5 and 6.

[0053] Figure 16 (a) to (d) are schematic diagrams illustrating the shape of the silicon wafer end obtained in Example 7 and Comparative Example 2. Detailed Implementation

[0054] First, the ultraviolet absorbing coating of the present invention will be described.

[0055] The ultraviolet absorbing coating of the present invention contains an oxide precursor of one or more transition metals selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ce.

[0056] In this application, ultraviolet light refers to light with a wavelength in the range of 250–420 nm. Furthermore, in this application, a transition metal oxide precursor refers to a substance capable of forming an oxide of that transition metal through heating.

[0057] The ultraviolet absorbing coating of the present invention contains an oxide precursor of one or more transition metals selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ce as the oxide precursor of the transition metal. The transition metal is preferably selected from one or more of Ti, Cr, Mn, Fe, Co, Ni, Cu and Zn, and more preferably selected from one or more of Ti, Cr, Mn, Fe, Cu and Zn.

[0058] The oxide precursors of the aforementioned transition metals are preferably metal salts, metal salts, or organometallic compounds of the transition metals.

[0059] As the metal salt of the aforementioned transition metal, there are no particular limitations as long as it can form an oxide of the transition metal under heating and can dissolve in the ultraviolet absorbing coating. Examples include one or more metal salts selected from nitrates, sulfates, acetates, chlorides, phosphates, carbonates, hydroxides, etc.

[0060] As the metal salt of the aforementioned transition metal, there are no particular limitations as long as it can form an oxide of the transition metal under heating and can dissolve in the ultraviolet absorbing coating. Examples include one or more selected from vanadates, chromates, dichromates, manganates, permanganates, ferrates, ferrous ferrates, cobaltates, nickelates, cuprates, zincates, cerates, etc.

[0061] Organometallic compounds that are transition metals are not particularly limited as long as they can form oxides of transition metals upon heating and can dissolve in ultraviolet-absorbing coatings. Examples include: metal alkoxides, derivatives of metal alkoxides (e.g., organometallic compounds obtained by replacing part or all of the alkoxy groups of metal alkoxides with ligands such as acetylacetone or ethyl acetoacetate), stearic acid soaps, lauric acid soaps, castor oil alkyd soaps, octanoic acid soaps, naphthenic acid soaps, lignite acid soaps, and so on. One or more of the following: acid soap, sebacic acid soap, nutmeg acid soap, palmitic acid soap, 12-hydroxystearic acid soap, etc.

[0062] Oxides of one or more transition metals selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ce exhibit strong absorption of ultraviolet light.

[0063] In the case of the ultraviolet-absorbing coating of the present invention, by coating an object such as an optical element and heating it, an ultraviolet-absorbing film containing a transition metal oxide can be formed on the surface of the object such as the optical element. Therefore, in a device that can output ultraviolet light with high intensity and high light energy, even when an ultraviolet-absorbing coating is used to absorb ultraviolet light, the generation of stray light can be highly suppressed in a thin film state. In addition, when the ultraviolet-absorbing coating contains organic components such as solvents, the organic components can be removed by the above-mentioned heat treatment and a uniform transition metal oxide film can be formed. Therefore, the obtained ultraviolet-absorbing film can suppress the fading, peeling, and disappearance of the coating due to the deterioration of organic components even when exposed to ultraviolet light for a long time, and can exhibit excellent durability.

[0064] The ultraviolet-absorbing coating of the present invention may further contain one or more selected from silicon oxide precursors and aluminum oxide precursors.

[0065] In this application, silicon oxide precursor refers to a substance that can form silicon oxide by heating, and examples include: tetraethoxysilane, tetramethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, or oligomers formed from one or more of them, and polysilazane.

[0066] In this application, aluminum oxide precursor refers to a substance that can form aluminum oxide by heating. Examples include one or more aluminum alkoxides such as aluminum sec-butoxide and aluminum isobutoxide, aluminum chelate compounds obtained by modifying part or all of the alkoxy groups of the above aluminum alkoxides with chelating agents such as acetylacetone and ethyl acetoacetate, aluminum soaps such as aluminum stearate, aluminum octoate, and aluminum naphthenate, aluminum nitrate nonahydrate, aluminum chloride, and polyaluminum chloride.

[0067] The ultraviolet absorbing coating of the present invention, by further containing one or more selected from silicon oxide precursors and aluminum oxide precursors, can easily form a composite film of transition metal oxide and silicon oxide or aluminum oxide during the formation of the ultraviolet absorbing film. Through this composite film, the adhesion of the ultraviolet absorbing film obtained by coating the ultraviolet absorbing coating to optical components can be improved, making the ultraviolet absorbing film less prone to peeling.

[0068] The ultraviolet-absorbing coating of the present invention may also contain colorants.

[0069] In the case where the ultraviolet absorbing coating of the present invention contains a colorant, the colorant is a colorant that does not undergo gelation or precipitation of the absorbent film raw material, is stably dissolved or dispersed in the coating, and has the ability to absorb visible light. Preferably, it is a colorant that can disappear by decomposition, volatilization, etc. at the temperature at which the oxide precursor of the transition metal contained in the ultraviolet absorbing coating forms a metal oxide, or a colorant that can form an inorganic oxide.

[0070] As colorants, dyes and pigments can be listed, with dyes being preferred. Considering their ease of solubility in coatings and their low likelihood of aggregation, dyes are preferred as colorants.

[0071] When the aforementioned colorant is a dye, there are no particular limitations as long as it can dissolve in the ultraviolet-absorbing coating to make the coating film visible. Examples of dyes selected include methylene blue, triphenylmethane pigments (e.g., malachite green), ice dyes, azo dyes, acridine, aniline dyes (e.g., aniline black), indanthrene, eosin, Congo red, dihydroindole, phenazine derivative pigments (e.g., neutral red), phenolphthalein, fuchsin, fluorescein, Para red, mauve, caramel pigment, gardenia pigment, anthocyanin pigment, annatto pigment, capsicum pigment, safflower pigment, red yeast rice pigment, flavonoid pigment, carmine pigment, amaranth (red No. 2), erythrosine (red No. 3), Allura Red AC (red No. 40), New Coccine (red No. 102), Phloxine (red No. 104), and rose red. One or more of the following: bengal (Red 105), Acid Red (Red 106), Tartrazine Yellow (Yellow 4), Sunset Yellow FCF (Yellow 5), Fast Green FCF (Green 3), Brilliant Blue FCF (Blue 1), and Sulfonated Indigo (Blue 2).

[0072] When the aforementioned colorant is a pigment, any pigment that is not prone to aggregation is acceptable; there are no particular limitations. Examples include iron oxide red, ultramarine blue, Prussian blue, carbon black, isoindolineone, isoindoline, methylimine, anthraquinone, anthrone, oxanthracene, pyrrolopyrroledione, dinaphthalene, perinone, quinacrine, indigoid, and dioxane. One or more of aziridines and phthalocyanines.

[0073] The ultraviolet-absorbing film obtained by the ultraviolet-absorbing coating of the present invention can highly suppress the generation of stray light even in a thin film state. However, when a thinner ultraviolet-absorbing film is desired, the thickness of the coating film formed during the coating process also becomes thinner, making it difficult to identify whether it is coated on a given area, whether the required amount is applied, or whether it adheres to non-coated surfaces such as the incident and exit surfaces of the lens. When the ultraviolet-absorbing coating is transparent, the identification of the coating film becomes even more difficult. Although sometimes the ultraviolet-absorbing coating is pre-colored using transition metal oxide precursors, the degree of coloring is low, and the coating film thickness is thinner, making it equally difficult to identify the coating film. Before drying and heat-treating the coating film to form the ultraviolet-absorbing film, the coated film may be mistakenly wiped off. Furthermore, if heat treatment is performed directly, the coating may sinter onto the surface of the optical element and be difficult to remove, resulting in a lower product yield.

[0074] When the ultraviolet-absorbing coating of the present invention further contains a colorant, the presence or absence of a coating film can be easily identified during the coating process, which can easily improve the manufacturing efficiency of optical components and the yield of products.

[0075] When the ultraviolet-absorbing coating of the present invention contains a colorant, the proportion of the colorant is preferably 0.005 to 20% by mass, more preferably 0.01 to 10% by mass, and even more preferably 0.05 to 5% by mass, in terms of increasing proportion (i.e., the amount of colorant added / the total amount of ultraviolet-absorbing coating after adding the colorant), relative to the ultraviolet-absorbing coating.

[0076] The ultraviolet-absorbing coating of the present invention may also contain adhesive components or solvents.

[0077] In the case where the ultraviolet absorbing coating of the present invention contains a binder component or solvent, the binder component or solvent is preferably one that disappears through decomposition, volatilization, or the like at the temperature at which the oxide precursor of the transition metal contained in the ultraviolet absorbing coating forms a metal oxide.

[0078] As the aforementioned adhesive component, one or more of the following can be selected: polyvinylpyrrolidone, polyethylene glycol, polyvinyl alcohol, hydroxyethyl cellulose, hydroxypropyl cellulose, polyvinyl acetate, chitosan, etc.

[0079] By including a binder component in the ultraviolet-absorbing coating of the present invention, the oxide precursor of the transition metal can be stably and uniformly coated on the substrate, thereby enabling the easy formation of an ultraviolet-absorbing film.

[0080] The aforementioned binder can be appropriately selected according to the type of transition metal oxide precursor contained in the ultraviolet absorbing coating. For example, if the ultraviolet absorbing coating contains manganese oxide precursor as a transition metal oxide precursor, it is preferable to contain polyvinylpyrrolidone as a binder. By containing polyvinylpyrrolidone as a binder, the manganese oxide precursor can be well dissolved in the ultraviolet absorbing coating.

[0081] In addition, as a solvent, it is preferable to be a solvent that disappears through decomposition, volatilization, or the like at the temperature at which the oxide precursor of the transition metal contained in the ultraviolet absorbing coating forms a metal oxide.

[0082] As solvents, one or more can be selected from methanol, ethanol, n-propanol, isopropanol, n-butanol and other butanols, 2-methoxyethanol, 2-ethoxyethanol, ethylene glycol, diethylene glycol, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, propionic acid, butyric acid, etc.

[0083] In the ultraviolet-absorbing coating of the present invention, the proportion of transition metal oxide precursors, converted to oxides of each transition metal, is preferably 0.1 to 20.0% by mass, more preferably 0.5 to 15.0% by mass, and even more preferably 1.0 to 10.0% by mass.

[0084] In the case of the ultraviolet absorbing coating of the present invention, by keeping the content of the transition metal oxide precursor within the above-mentioned range, cracking and peeling can be effectively suppressed when forming an ultraviolet absorbing film.

[0085] Generally, when an inorganic oxide film is formed on a substrate using a metal oxide precursor, the substrate side of the inorganic oxide film is bonded to the substrate and shrinkage is easily suppressed. In contrast, the outer surface side of the inorganic oxide film shrinks freely and is accompanied by a large volume shrinkage. Since the metal oxide film is less flexible than the organic film, the stress generated by the volume shrinkage makes the oxide film prone to cracking and peeling.

[0086] When the content of the aforementioned transition metal oxide precursor is less than 0.1% by mass, the thickness of the resulting transition metal oxide film tends to be thin, making it difficult to obtain the target absorption characteristics. When the content of the aforementioned transition metal oxide precursor exceeds 20.0% by mass, the thickness of the resulting transition metal oxide film becomes thicker, the aforementioned stress tends to increase, and the aforementioned cracks and peeling are more likely to occur.

[0087] It should be noted that, in this application, the oxides of transition metals used in calculating the proportion of transition metals refer to TiO2 when the transition metal is Ti, V2O5 when the transition metal is V, Cr2O3 when the transition metal is Cr, Mn2O3 when the transition metal is Mn, Fe2O3 when the transition metal is Fe, CoO when the transition metal is Co, NiO when the transition metal is Ni, CuO when the transition metal is Cu, ZnO when the transition metal is Zn, and CeO2 when the transition metal is Ce.

[0088] In the case of the ultraviolet absorbing coating of the present invention, by making the content ratio of the transition metal within the above range, not only can the transition metal be well dissolved, but also an ultraviolet absorbing film of desired thickness can be easily formed.

[0089] When the ultraviolet absorbing coating of the present invention further contains one or more selected from silicon oxide precursors and aluminum oxide precursors, the total content of transition metal oxide precursors converted into the oxides thereof is preferably 1.0 to 30.0% by mass, more preferably 2.0 to 25.0% by mass, and even more preferably 3.0 to 20.0% by mass, based on their oxides.

[0090] With respect to the ultraviolet absorbing coating of the present invention, by making the total content of one or more selected from silicon oxide precursors and aluminum oxide precursors within the above-mentioned range, the adhesion of the obtained ultraviolet absorbing film to the substrate can be improved, and the occurrence of the above-mentioned cracks and peeling can be easily suppressed.

[0091] It should be noted that, in this application document, the oxide used to calculate the silicon oxide precursor in the above-mentioned proportion refers to SiO2, and the oxide used to calculate the aluminum oxide precursor in the above-mentioned proportion refers to Al2O3.

[0092] For example, the ultraviolet absorbing coating of the present invention can be easily prepared by dissolving a transition metal oxide precursor and one or more of silicon oxide precursors and aluminum oxide precursors in the presence of a suitable binder, solvent, etc., in a desired amount.

[0093] According to the present invention, an ultraviolet absorbing coating can be provided, which can form a film that can highly suppress stray light generation in a thin film state and exhibit excellent durability.

[0094] Next, the ultraviolet absorbing film of the present invention will be described.

[0095] The ultraviolet absorbing film of the present invention is characterized in that it contains oxides of one or more transition metals selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ce.

[0096] The transition metal is preferably selected from one or more of Ti, Cr, Mn, Fe, Co, Ni, Cu and Zn, and more preferably selected from one or more of Ti, Cr, Mn, Fe, Cu and Zn.

[0097] Transition metals typically have multiple valence states, and therefore transition metal oxides can also take many forms. In this application, transition metal oxides refer not only to oxides of a specific transition metal, but also to forms in which multiple oxides coexist.

[0098] In addition, the ultraviolet absorbing film of the present invention can be an ultraviolet absorbing film in which two or more transition metal oxides are mixed.

[0099] Oxides of one or more transition metals selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ce exhibit strong absorption properties in the ultraviolet region.

[0100] The ultraviolet absorbing film of the present invention contains oxides of the aforementioned transition metals. Therefore, in devices capable of outputting high-intensity ultraviolet light, even when used for absorbing ultraviolet light, the generation of stray light can be highly suppressed in a thin film state. Furthermore, even under prolonged exposure to ultraviolet light, the coating can be prevented from fading, peeling, or disappearing, thus exhibiting excellent durability.

[0101] In addition to the aforementioned transition metal oxides, the ultraviolet absorbing film of the present invention may further contain one or more selected from silicon oxides and aluminum oxides.

[0102] By further containing one or more selected from silicon oxide and aluminum oxide in the ultraviolet absorbing film of the present invention, a composite film of transition metal oxide and silicon oxide or aluminum oxide can be formed. This composite film can improve the adhesion to the substrate and can easily suppress the occurrence of the above-mentioned cracks and peeling.

[0103] The ultraviolet absorbing film of the present invention preferably contains 20 to 100% by mass of the oxide of the aforementioned transition metal, more preferably 30 to 100% by mass, and even more preferably 35 to 100% by mass.

[0104] The thickness of the ultraviolet absorbing film of the present invention is preferably 50 μm or less, more preferably 25 μm or less, even more preferably 10 μm or less, and even more preferably 5 μm or less.

[0105] Although the ultraviolet absorbing film of the present invention can absorb ultraviolet light sufficiently even if it is a thin film, in order to achieve the purpose of the present invention, the film thickness of the ultraviolet absorbing film is preferably 0.01 μm or more, more preferably 0.02 μm or more, even more preferably 0.05 μm or more, and even more preferably 0.10 μm or more.

[0106] When the ultraviolet absorbing film of the present invention is disposed on the surface of an optical element, especially since the optical elements for LEDs are mostly very small, the processing tolerance of the optical element is usually ±100 μm, and in strict cases ±50 μm. Although it is required that the ultraviolet absorbing film be a thin film for accurate centering of the optical element, and also for suppressing positional misalignment of the individual optical elements when multiple optical elements are arranged in a configuration, the ultraviolet absorption performance of the ultraviolet absorbing film usually decreases when it is made into a thin film.

[0107] The ultraviolet absorbing film of the present invention contains oxides of specific transition metals. Therefore, in devices capable of outputting high-energy ultraviolet light with high intensity, even when used for absorbing ultraviolet light, the generation of stray light can be highly suppressed in a thin film form.

[0108] It should be noted that, in this application document, the thickness of the ultraviolet absorbing film refers to the value obtained by measuring the total thickness of the substrate and the ultraviolet absorbing film and the thickness of the substrate separately using a micrometer (MDH-25M manufactured by Mitutoyo), and the difference between the two.

[0109] In the ultraviolet absorbing film of the present invention, the optical density (OD) of the ultraviolet absorbing film is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more.

[0110] By keeping the optical density (OD) within the aforementioned range, even when used for absorbing ultraviolet light, the generation of stray light can be highly suppressed in a thin film-like manner in devices capable of outputting high-intensity ultraviolet light.

[0111] It should be noted that, in this application document, optical density (OD) refers to the value measured using an ultraviolet-visible-near-infrared spectrophotometer (U-4100 manufactured by Hitachi, Ltd.) when irradiated with light containing the wavelength or wavelength range of light that is the target of absorption.

[0112] Ideally, the ultraviolet absorbing film of the present invention should be free of cracks (fissures) when observed with the naked eye.

[0113] By ensuring that the ultraviolet absorbing film of the present invention is free of cracks (fissures), it is easy to prevent the ultraviolet absorbing film from being peeled off from the film-forming object such as optical elements, and it is easy to prevent the formation of debris, thereby easily obtaining the desired stray light absorption effect.

[0114] For the ultraviolet absorbing film of the present invention, it is preferable to provide it on the surface of the portion outside the original optical path in optical elements such as lenses, prisms, and lens barrels. For example, it can preferably be provided on the surface of the portion outside the incident / exit surface of optical elements such as the edge of the lens, or on the inner surface of the lens barrel.

[0115] By providing the ultraviolet absorption film of the present invention on the surface outside the original optical path, even when used for absorbing ultraviolet light, the generation of stray light can be highly suppressed in a thin film form in a device capable of outputting high-intensity ultraviolet light with high energy.

[0116] The ultraviolet absorbing film of the present invention can preferably be made using the ultraviolet absorbing coating of the present invention.

[0117] As a method for manufacturing the ultraviolet absorbing film of the present invention, examples include: coating a substrate (the object to which the absorbing film is to be formed) with the ultraviolet absorbing coating of the present invention and forming the film by the sol-gel method.

[0118] As a method for producing such an ultraviolet-absorbing film, examples include: applying the ultraviolet-absorbing coating of the present invention to the object to which the film is to be formed using a brush, a sprayer, or by dip-coating or spin-coating, thereby forming a coating film of desired thickness, and then subjecting it to appropriate drying and heat treatment. The temperature during the heat treatment is preferably 300 to 1000°C, and the treatment time is preferably 1 minute to 12 hours.

[0119] The above method can be used to form a target metal oxide film (ultraviolet absorption film).

[0120] With respect to the ultraviolet absorbing film of the present invention, even when used for absorbing ultraviolet light, it can suppress the generation of stray light to a high degree in a thin film form in a device that can output high-intensity ultraviolet light with high energy.

[0121] Next, the light-absorbing film of the present invention will be described.

[0122] The light-absorbing film of the present invention is characterized in that it comprises a stack, which is a stack of the ultraviolet absorbing film of the present invention and an absorbing film that absorbs at least visible light or infrared light.

[0123] The details of the ultraviolet absorbing film of the present invention are as described above.

[0124] In the light-absorbing film of the present invention, the absorbent film that absorbs visible light or infrared radiation can be disposed on the ultraviolet-absorbing film of the present invention by coating with a known coating agent capable of forming an absorbent film for visible light or infrared radiation.

[0125] As the aforementioned coating agent, examples include one or more selected from anti-reflective coatings (manufactured by CANON CHEMICALS, model CS-37, etc.) and near-infrared shielding materials (manufactured by Sumitomo Metal Mining Co., Ltd., model YMF-02A, etc.).

[0126] The light-absorbing film of the present invention can be configured such that an ultraviolet absorbing film is located on the light incident side, or it can be configured such that an absorbing film for absorbing visible light or infrared light is located on the light incident side.

[0127] With respect to the light-absorbing film of the present invention, by having an absorption film that absorbs at least one of visible light or infrared light on the ultraviolet absorption film of the present invention, even when applied to a light emitter that emits light containing high-energy ultraviolet light, visible light, and infrared light, the generation of stray light can be highly suppressed.

[0128] Examples of light-emitting elements that emit light containing high energy, such as ultraviolet, visible, and infrared light, include: mercury-xenon lamps, xenon lamps, metal halide lamps, ultraviolet LEDs (UV-LEDs), white LEDs, and LED units that integrate multiple wavelengths of LEDs on a substrate.

[0129] Next, the optical element of the present invention will be described.

[0130] The optical element of the present invention is characterized in that it has an ultraviolet absorbing film or light absorbing film of the present invention on its surface.

[0131] The details of the ultraviolet absorbing film or light absorbing film of the present invention are as described above. Furthermore, the details of the deposition location and deposition method of the ultraviolet absorbing film in the optical element of the present invention are also as described above.

[0132] As optical elements of the present invention, one or more items selected from lenses, prisms, mirror tubes, mirrors, etc., which are commonly referred to as optical elements or optical components, may be listed.

[0133] The optical element of the present invention will be described below with specific examples.

[0134] Figure 1 This is a schematic diagram showing a cross-section of a conventional optical element (biconvex lens) L, which is an optical element. Figure 1 (a) and a schematic cross-sectional view of the optical element (biconvex lens) L of the present invention, as an example of an optical element. Figure 1(b)) Generally, for biconvex lenses, such as Figure 1 As shown in (a), a portion of the ultraviolet light I incident on the optical surface enters from the edge (side) of the lens and is reflected by the inner wall surface of the lens edge to generate stray light S, but as Figure 1 As shown in (b), since the optical element of the present invention has an ultraviolet absorption film A at the edge of the biconvex lens L, ultraviolet light can be effectively absorbed at the edge of the lens, thus suppressing the generation of stray light S (for convenience, in...). Figure 1 (b) shows stray light S generated when the biconvex lens L does not have an ultraviolet absorption film A, represented by a dashed line.

[0135] exist Figure 1 The example uses a biconvex lens as lens L, but for lens L, any one of a biconcave lens, a plano-convex lens, or a plano-concave lens can be used instead of a biconvex lens. In this case, the ultraviolet absorbing film A is disposed at the edge of each lens.

[0136] Figure 2 This is a schematic diagram showing a cross-sectional view of a concave-convex lens as an example of an optical element of the present invention. Generally, for concave-convex lenses, such as... Figure 2 As shown, a portion of the ultraviolet light I incident on the optical surface enters from the edge (side) of the lens or is reflected from the inner wall surface of the lens edge, thereby generating stray light S. However, since the optical element of the present invention has an ultraviolet absorption film A at the edge of the lens L, ultraviolet light can be effectively absorbed at the lens edge, thus suppressing the generation of stray light (for convenience, in...). Figure 2 The dashed line represents stray light S generated when the concave-convex lens L does not have an ultraviolet absorption film A.

[0137] In addition, Figure 2 In the concave-convex lens shown, a light-blocking shield is usually provided on the flat portion of the incident surface to selectively direct light into the concave portion of the incident surface. However, without this shield, stray light S is generated from the light entering through the flat portion of the incident surface. Therefore, in Figure 2 In the example shown, an ultraviolet absorbing film A is also provided on the plane portion of the incident surface. By effectively absorbing ultraviolet light on the plane portion on the incident surface side, it can serve as the aforementioned shield and simultaneously suppress the generation of stray light.

[0138] Figure 3 This is a schematic diagram showing a cross-sectional view of a lens barrel as an example of an optical element of the present invention. Generally, for a lens barrel, such as... Figure 3 As shown, a portion of the incident light I entering the lens barrel surface is reflected at the inner wall surface of the lens barrel to generate stray light S, but because Figure 3The microscope tube shown has an ultraviolet-absorbing film A on the inner wall surface of the tube T, which effectively absorbs light and suppresses the generation of stray light (for convenience, in...). Figure 3 The dashed line in the image represents stray light S generated when the lens barrel T does not have an ultraviolet absorption film A.

[0139] Traditionally, the lens barrel has been processed by impregnating a black dye into a pore created through an alumina film treatment on the inner wall surface, resulting in a black alumina film. However, since this black dye is an organic compound, it decomposes and fades when exposed to short-wavelength or high-intensity light, such as ultraviolet light, causing stray light to easily accumulate. In contrast, the optical element of this invention has an ultraviolet-absorbing film containing transition metal oxides, thus exhibiting excellent durability even under high-intensity ultraviolet light and suppressing the generation of stray light.

[0140] Figure 4 This is a schematic diagram showing a cross-sectional view of a lens case, which is an example of an optical element of the present invention. Generally, for a lens case, such as... Figure 4 As shown, ultraviolet light from the entrance of the mirror box exits from the exit port. A portion of the incident ultraviolet light I is reflected by the inner wall of the mirror box, generating stray light S. In contrast, in Figure 4 In the mirror box MB shown, the inner wall surface of the mirror box MB has an ultraviolet absorption film A on the inner wall surface (excluding the reflector section) and the edges of the entrance or exit port. This effectively absorbs ultraviolet light from the inner surface, suppressing the generation of stray light. (For convenience, in...) Figure 4 The dashed line in the image represents stray light S generated when the lens case MB does not have the ultraviolet absorption film A.

[0141] In addition, although not illustrated, the optical element of the present invention can also be an optical element formed by providing the ultraviolet absorption film of the present invention on the surfaces of the prism other than the incident surface, the exit surface, and the reflecting surface.

[0142] For the optical element of the present invention, in a device capable of outputting high-energy ultraviolet light with high intensity, even when used for absorbing ultraviolet light, or when used for absorbing visible light or infrared light while absorbing ultraviolet light, the generation of stray light can be highly suppressed in a thin film form.

[0143] Next, the optical unit of the present invention will be described.

[0144] The optical unit of the present invention is characterized by having the optical element of the present invention.

[0145] The details of the optical element of the present invention are as described above.

[0146] The optical unit of the present invention can be any unit that has the optical element of the present invention, and there are no particular limitations.

[0147] The optical unit of the present invention typically includes optical elements and a light source.

[0148] As a light source, any light source capable of emitting light containing ultraviolet light is acceptable, with no particular restrictions. Examples include one or more discharge lamps selected from ultraviolet LEDs (UV-LEDs), short-arc lamps, long-arc lamps, etc.

[0149] Figure 5 This is a diagram illustrating the optical unit of the present invention. Figure 5 The image above is a schematic diagram viewed from above. Figure 5 The image below is a cross-sectional view taken from the side.

[0150] Figure 5 The optical unit shown is formed by setting four ultraviolet LEDs (LED chips) D on a substrate B, and sequentially setting a first lens L1, a second lens L2 and a third lens L3 from the ultraviolet LED side (irradiation side) to the emission side. The edges of the first lens L1, the second lens L2 and the third lens L3 have the ultraviolet absorption film of the present invention.

[0151] The optical unit of the present invention can highly suppress the generation of stray light and simultaneously provide light irradiation, even when used in a device capable of outputting high-intensity ultraviolet light, or when used to absorb visible or infrared light while absorbing ultraviolet light.

[0152] Next, the light irradiation device of the present invention will be described.

[0153] The light irradiation device of the present invention is characterized by having the optical unit of the present invention.

[0154] The details of the optical unit of the present invention are as described above.

[0155] Examples of light irradiation devices according to the present invention include: point-type ultraviolet light sources, linear ultraviolet light sources, area-type ultraviolet light sources, light guide type ultraviolet light sources, and peripheral exposure light source devices.

[0156] The light irradiation device of the present invention contains one or more optical units of the present invention, and usually contains two or more optical units of the present invention.

[0157] Figure 6 This is a top view illustrating the light irradiation device of the present invention. Figure 6 In the example shown, the light illumination device contains 25 Figure 5 The optical units U shown can work together to illuminate the object being irradiated.

[0158] Even if the light irradiation device of the present invention is a device capable of outputting high-intensity ultraviolet light, or a device capable of outputting visible light or infrared light while outputting ultraviolet light, it can still highly suppress the generation of stray light and highly suppress stray light from mixing into the original irradiation light due to the optical unit of the present invention.

[0159] [Example]

[0160] The present invention will be further described below through examples and comparative examples, but the present invention is not limited to the following examples.

[0161] (Example 1)

[0162] 19.4 g of ethylene glycol (indicative formula: C2H4(OH)2) and 12.6 g of ferric(III) nitrate nonahydrate (indicative formula: Fe(NO3)39H2O) were added to a glass container. The mixture was stirred at room temperature for 2 hours using a magnetic stirrer to dissolve the ferric(III) nitrate nonahydrate in the ethylene glycol. Then, 68.0 g of isopropanol (indicative formula: CH3CH(OH)CH3) was added, and the mixture was stirred further at room temperature for 2 hours. This prepared a brown, transparent, and uniform coating solution (Fe) for forming an absorbent film. x O y (Ultraviolet-absorbing coating) 100g.

[0163] Assuming the coating solution is heat-treated to completely oxide the ferric nitrate, the solid content in the coating solution used to form the absorbent film is 2.5% by mass, converted to Fe2O3.

[0164] The coating solution for forming the absorbent film was applied to both sides of a glass substrate (manufactured by Matsunami Glass Industry Co., Ltd., S1127, 76 mm long × 26 mm wide × 1.0 to 1.2 mm thick) using an immersion method at a lifting speed of 30 cm / min. The resulting film was a transparent and uniform film with a light orange color.

[0165] The glass substrate with the thin film was dried at 70°C for 1 hour, then placed in a heat treatment furnace and heated from room temperature to 500°C at a rate of 200°C / hour in an atmospheric atmosphere, and held at 500°C for 1 hour, thereby forming iron oxide (Fe) on the glass substrate. x O y The obtained ultraviolet-absorbing film has a thickness of less than 1 μm.

[0166] Through the above heat treatment, the film changed from light orange to dark orange, and the obtained ultraviolet absorption film was uniform, with no cracks or peeling detected.

[0167] The transmittance curves of the substrate with and without the ultraviolet absorption film are shown below. Figure 7 .

[0168] Figure 7 The dashed line represents the transmittance curve of a single substrate (without an ultraviolet absorption film), while the solid line represents the transmittance curve of a substrate with Fe. x O y The transmittance curve of the substrate with the ultraviolet absorption film shows that, due to the absorption caused by the iron oxides constituting the ultraviolet absorption film in the ultraviolet region of 250-420nm, the transmittance of the solid line (with the ultraviolet absorption film) is highly suppressed in the entire ultraviolet region compared with the dashed line (the substrate alone).

[0169] (Evaluation of UV absorption effect)

[0170] With the optically polished surface of the quartz glass substrate (20mm long × 50mm wide × 2mm thick, with the main surface of 20mm long × 50mm wide being an optically polished surface and the other main surface being a #1000 frosted surface) covered by masking tape, the above-mentioned coating liquid for forming the absorption film is applied to the frosted surface by immersion at a lifting speed of 30cm / min.

[0171] The masking tape was peeled off from the quartz glass substrate with the thin film, dried at 70°C for 1 hour, and then placed in a heat treatment furnace. The temperature was increased from room temperature to 500°C at a rate of 200°C / hour and held at 500°C for 1 hour, thereby forming iron oxide (Fe) on the frosted surface of the quartz glass substrate. x O y The resulting ultraviolet-absorbing film is made of iron oxide (Fe). x O y The thickness of the ultraviolet-absorbing film is less than 1 μm.

[0172] Using the obtained quartz glass substrate with an ultraviolet-absorbing film, such as Figure 8 As briefly shown, the intensity of light incident from the side (end face) of the quartz glass substrate G on the main surfaces (frosted surface W and optically polished surface P) is measured. Figure 8 The above figure is a schematic diagram showing the overall measurement system. Figure 8 The image below is an enlarged representation of the area enclosed by the circle in the image above.

[0173] Right now,

[0174] (1) to become Figure 8The configuration shown involves placing a quartz glass substrate G (20mm long × 50mm wide × 2mm thick, with the main surface of the 20mm long × 50mm wide substrate being an optically polished surface P and the other main surface being a #1000 frosted surface W) on a light receiver R equipped with a light receiver R, before the formation of the aforementioned ultraviolet absorption film. The output of the UV-LED light source (peak wavelength 365nm) is adjusted so that when ultraviolet light L is horizontally irradiated from the side at the end of the quartz glass substrate, the display value of the light receiver LR is 10.00 mW / cm². 2 ,

[0175] (2) Next, as Figure 8 As shown, the quartz glass substrate described above is replaced with a quartz glass substrate G (20mm long × 50mm wide × 2mm thick, with the 20mm long × 50mm wide main surface being the optically polished surface P and the other main surface being the #1000 frosted surface W) whose main surfaces are a frosted surface W with an ultraviolet absorption film C. Similarly, ultraviolet light L is horizontally irradiated onto the end side of the quartz glass substrate. At this time,

[0176] (3) The incident light undergoes internal reflection within the quartz glass substrate and is simultaneously absorbed by the ultraviolet absorption film C. The intensity I of the emitted light, which is emitted to the light-receiving part LR side, is measured. l Relative to the intensity I of the incident light O The proportion ((I) l / I O (×100).

[0177] As a result, when using a quartz glass substrate without an ultraviolet absorption film, the intensity (I) of the emitted light emitted to the R side of the light receiver is... l The value is 10.00 mW / cm. 2 In contrast, when using a quartz glass substrate G with an ultraviolet absorption film C formed on it, the intensity of the emitted light (I) emitted to the light receiver R side is higher. l The value is 0.20 mW / cm. 2 The intensity I of the emitted light emitted to the R side of the photodetector l Relative to the intensity I of the incident light mentioned above O The proportion ((I) l / I O ()×100) is 2.0%.

[0178] (Durability Evaluation)

[0179] like Figure 9 As shown, for the same quartz glass substrate with an ultraviolet absorption film used in the "Evaluation of Ultraviolet Absorption Effect" above, the ultraviolet absorption film C is applied at an incident angle of 90° and a wavelength of 2000 mW / cm². 2After 5000 hours of intense ultraviolet radiation, the ultraviolet absorption film C did not develop cracks or peeling, and its transmittance did not change before and after ultraviolet irradiation.

[0180] (Example 2)

[0181] A mixture of 16.0 g of 0.7% hydrochloric acid aqueous solution and 18.9 g of isopropanol was slowly added to a mixed solution of 23.6 g of tetraethoxysilane (indicative formula: Si(C2H5O)4) and 18.9 g of isopropanol, and stirred for 2 hours. Then, 22.6 g of chromium(III) nitrate nonahydrate (indicative formula: Cr(NO3)3·9H2O) was added, and the mixture was stirred for another 2 hours. This prepared a dark blue, transparent, and uniform coating solution (chromium oxide-SiO2 system (Cr...) for forming an absorbent film. x O y -SiO2-based) UV absorbing coating 100g.

[0182] Assuming the coating solution is heat-treated to completely convert chromium(III) nitrate into Cr2O3 and tetraethoxysilane into SiO2, the solid component of the resulting coating solution for forming the absorbent film contains 20 mol% Cr2O3 and 80 mol% SiO2. The solid component of the coating solution (assuming that it is completely converted into oxides by heat treatment) is 11.1% by mass, converted to 20Cr2O3·80SiO2.

[0183] The coating solution for forming the absorbent film was applied to both sides of a glass substrate (manufactured by Matsunami Glass Industry Co., Ltd., S1127, 76 mm long × 26 mm wide × 1.0 to 1.2 mm thick) using an immersion method at a lifting speed of 30 cm / min. The resulting film was a transparent and uniform film with a light navy blue color.

[0184] Using the same conditions as in Example 1, i.e., drying the glass substrate with the thin film at 70°C, then placing it in a heat treatment furnace, heating it from room temperature to 500°C at a rate of 200°C / hour in an atmospheric atmosphere, and holding it at 500°C for 1 hour, a chromium oxide-SiO2 system (Cr) was formed on the glass substrate. x O y The obtained chromium oxide-SiO2 system (Cr-SiO2-based) ultraviolet absorbing film. x O y The thickness of the SiO2-based ultraviolet absorbing film is less than 1 μm.

[0185] Through the above heat treatment, the film changed from light navy blue to dark green, and the resulting ultraviolet absorption film was uniform, with no cracks or peeling observed.

[0186] The transmittance curves of the substrate with and without the ultraviolet absorption film are shown in the figure. Figure 10 .

[0187] Figure 10 The dashed line represents the transmittance curve of a single substrate (without an ultraviolet absorption film), while the solid line represents the transmittance curve of a substrate with Cr. x O y The transmittance curve of the substrate with the SiO2-based ultraviolet absorbing film shows that, due to the absorption of chromium oxide constituting the ultraviolet absorbing film in the ultraviolet region of 250–420 nm, the transmittance of the solid line (with ultraviolet absorbing film) is highly suppressed in the entire ultraviolet region compared with the dashed line (the substrate alone).

[0188] Using the above-described coating solution for forming the absorption film, the ultraviolet absorption effect was evaluated in the same manner as in Example 1. The results showed that when using a quartz glass substrate G with the ultraviolet absorption film C formed on it, the intensity (IA) of the emitted light emitted to the light receiver R side was [value missing]. l The value is 0.19 mW / cm. 2 The intensity I of the emitted light emitted to the R side of the photodetector l Relative to the intensity I of the incident light mentioned above O The proportion ((I) l / I O (1) × 100) is 1.9%.

[0189] In addition, durability was evaluated in the same manner as in Example 1, and the results were as follows: Figure 9 As shown, for a quartz glass substrate with an ultraviolet absorbing film, the ultraviolet light is incident from the frosted surface side with the ultraviolet absorbing film C at an angle of 90° and a wavelength of 2000 mW / cm. 2 After 5000 hours of intense ultraviolet radiation, the ultraviolet absorption film C did not crack or peel, and its transmittance did not change before and after ultraviolet irradiation.

[0190] (Example 3)

[0191] In a glass container, 4.1 g of polyvinylpyrrolidone K-90 was slowly added to 85.1 g of 2-methoxyethanol (indicative formula: CH3OCHCH2OH), and stirred for 2 hours to dissolve the polyvinylpyrrolidone in the 2-methoxyethanol. Then, 10.6 g of manganese(II) nitrate hexahydrate (indicative formula: Mn(NO3)26H2O) was added to this solution, and the mixture was stirred for another 2 hours. This prepared a uniform, very light brown coating solution (manganese oxide-based (Mn...) for forming an absorbent film. x O y (100g of UV-absorbing coating)

[0192] Assuming the coating solution is heat-treated to completely convert manganese(II) nitrate into Mn2O3, the solid content in the coating solution used to form the absorbent film, converted to Mn2O3, is 2.9% by mass.

[0193] The coating solution for forming the absorbent film was applied to both sides of a glass substrate (manufactured by Matsunami Glass Industry Co., Ltd., S1127, 76 mm long × 26 mm wide × 1.0 to 1.2 mm thick) using an immersion method at a lifting speed of 20 cm / min. The resulting film was colorless, transparent, and uniform.

[0194] Using the same conditions as in Example 1, i.e., drying the glass substrate with the thin film at 70°C, then placing it in a heat treatment furnace, heating it from room temperature to 500°C at a rate of 200°C / hour in an atmospheric atmosphere, and holding it at 500°C for 1 hour, a 1.2 μm thick manganese oxide (Mn) film was formed on the glass substrate. x O y (System) Ultraviolet absorbing film.

[0195] Through the above heat treatment, the film changed from colorless and transparent to dark brown. The resulting ultraviolet absorbing film was uniform, and no cracks or peeling were detected.

[0196] The transmittance curves of the substrate with and without the ultraviolet absorption film are shown in the figure. Figure 11 .

[0197] Figure 11 The dashed line represents the transmittance curve of a single substrate (without the UV absorption film), while the solid line represents the transmittance curve with Mn. x O y The transmittance curve of the substrate with the ultraviolet absorption film shows that, due to absorption in the ultraviolet region of 250–420 nm caused by the manganese oxides constituting the ultraviolet absorption film, the transmittance of the solid line (with the ultraviolet absorption film) is highly suppressed across the entire ultraviolet region compared to the dashed line (the substrate alone). (It should be noted that in…) Figure 11 In, containing Mn x O y The transmittance of the substrate of the ultraviolet absorption film is 0% across the entire measurement wavelength range, therefore Figure 11 The horizontal axis with Mn x O y (The transmittance curves of the substrate with the ultraviolet absorption film are superimposed).

[0198] Using the above-described coating solution for forming the absorption film, the ultraviolet absorption effect was evaluated in the same manner as in Example 1. The results showed that when using a quartz glass substrate G with the ultraviolet absorption film C formed on it, the intensity (IA) of the emitted light emitted to the light receiver R side was [value missing]. l The value is 0.15 mW / cm 2 The intensity I of the emitted light emitted to the R side of the photodetector l Relative to the intensity I of the incident light mentioned above O The proportion ((I)l / I O (1) × 100) is 1.5%.

[0199] In addition, durability was evaluated in the same manner as in Example 1, and the results were as follows: Figure 9 As shown, for a quartz glass substrate with an ultraviolet absorbing film, the ultraviolet light is incident from the frosted surface side with the ultraviolet absorbing film C at an angle of 90° and a wavelength of 2000 mW / cm. 2 After 5000 hours of intense ultraviolet radiation, the ultraviolet absorption film C did not crack or peel, and its transmittance did not change before and after ultraviolet irradiation.

[0200] (Example 4)

[0201] A colorless, transparent, and uniform coating solution for forming an absorbent film (manganese oxide-SiO2 system) was prepared by slowly adding a mixture of 17.1 g of 0.7% hydrochloric acid aqueous solution and 20.2 g of isopropanol to a mixed solution of 25.2 g of tetraethoxysilane (indicative formula: Si(C2H5O)4) and 20.2 g of isopropanol, stirring for 2 hours, and then adding 17.3 g of manganese(II) nitrate hexahydrate and stirring for another 2 hours. x O y -SiO2-based) UV absorbing coating 100g.

[0202] Assuming the coating solution is heat-treated to completely convert manganese(II) nitrate into Cr2O3 and tetraethoxysilane into SiO2, the solid component of the resulting coating solution for forming the absorbent film contains 20 mol% Mn2O3 and 80 mol% SiO2. The solid component of the coating solution (assuming that it is completely converted into oxides by heat treatment) is 12.0% by mass, converted to 20Mn2O3·80SiO2.

[0203] The coating solution for forming the absorbent film was applied to both sides of a glass substrate (manufactured by Matsunami Glass Industry Co., Ltd., S1127, 76 mm long × 26 mm wide × 1.0 to 1.2 mm thick) using an immersion method at a lifting speed of 30 cm / min. The resulting film was colorless, transparent, and uniform.

[0204] Using the same conditions as in Example 1, i.e., drying the glass substrate with the thin film at 70°C, then placing it in a heat treatment furnace, heating it from room temperature to 500°C at a rate of 200°C / hour in an atmospheric atmosphere, and holding it at 500°C for 1 hour, a manganese oxide-SiO2 system (MnO2) was formed on the glass substrate. x O y -SiO2 system) ultraviolet absorbing film. Manganese oxide-SiO2 system (Mn x O y The thickness of the ultraviolet absorbing film (SiO2 system) is less than 1 μm.

[0205] Through the above heat treatment, the film changed from colorless and transparent to brown, and the resulting ultraviolet absorbing film was uniform, with no cracks or peeling observed.

[0206] The transmittance curves of the substrate with and without the ultraviolet absorption film are shown in the figure. Figure 12 .

[0207] Figure 12 The dashed line represents the transmittance curve of a single substrate (without the UV absorption film), while the solid line represents the transmittance curve with Mn. x O y The transmittance curves of the SiO2-based ultraviolet-absorbing film substrate show that, due to absorption in the 250–420 nm ultraviolet region caused by the manganese oxides constituting the ultraviolet-absorbing film, the transmittance of the solid line (with the ultraviolet-absorbing film) is highly suppressed across the entire ultraviolet region compared to the dashed line (the substrate alone).

[0208] Using the above-described coating solution for forming the absorption film, the ultraviolet absorption effect was evaluated in the same manner as in Example 1. The results showed that when using a quartz glass substrate G with the ultraviolet absorption film C formed on it, the intensity (IA) of the emitted light emitted to the light receiver R side was [value missing]. l The value is 0.21 mW / cm. 2 The intensity I of the emitted light emitted to the R side of the photodetector l Relative to the intensity I of the incident light mentioned above O The proportion ((I) l / I O ()×100) is 2.1%.

[0209] In addition, durability was evaluated in the same manner as in Example 1, and the results were as follows: Figure 9 As shown, for a quartz glass substrate with an ultraviolet absorbing film, the ultraviolet light is incident from the frosted surface side with the ultraviolet absorbing film C at an angle of 90° and a wavelength of 2000 mW / cm. 2 After 5000 hours of intense ultraviolet radiation, the ultraviolet absorption film C did not crack or peel, and its transmittance did not change before and after ultraviolet irradiation.

[0210] (Comparative Example 1)

[0211] Using a commercially available antireflective coating (GT-7II manufactured by CANON CHEMICALS) instead of the coating liquid for forming the absorption film, the ultraviolet absorption effect was evaluated in the same manner as in Example 1. The results showed that the intensity of the emitted light (I) reaching the R side of the receiver was... l The value is 0.19 mW / cm. 2 The intensity I of the emitted light emitted to the R side of the photodetector l Relative to the intensity I of the incident light mentioned aboveO The proportion ((I) l / I O (1) × 100) is 1.9%.

[0212] On the other hand, durability was evaluated in the same manner as in Example 1, and the result was that the color lightened (from black to gray) as the UV irradiation time passed, and peeling occurred after 1000 hours of irradiation.

[0213] The results of Examples 1 to 4 and Comparative Example 1 are summarized in Table 1.

[0214] [Table 1]

[0215]

[0216] As can be seen from Table 1, since the ultraviolet absorbing films obtained in Examples 1 to 4 contain oxides of specific transition metals, they can form ultraviolet absorbing films that can suppress stray light generation in a thin film state and exhibit excellent durability in devices that can output high-intensity ultraviolet light with high light energy, even when used for absorbing ultraviolet light.

[0217] In contrast, as shown in Table 1, the coating film obtained from the commercially available antireflective coating used in Comparative Example 1 contains organic resin but does not contain specific transition metal oxides. Therefore, it fades and peels during the durability test under ultraviolet light irradiation.

[0218] (Example 5)

[0219] In Example 3, the amount of manganese(II) nitrate hexahydrate (indicative formula: Mn(NO3)26H2O) added was changed from 10.6 g to 12.7 g. Otherwise, a uniform light brown coating solution (manganese oxide-based (Mn) nitrate hexahydrate) for forming an absorbent film was prepared in the same manner as in Example 3. x O y (Ultraviolet absorbing coating) 100g.

[0220] Assuming the coating solution is heat-treated to completely convert manganese(II) nitrate into Mn2O3, the solid content in the coating solution used to form the absorbent film, converted to Mn2O3, is 3.5% by mass.

[0221] Similar to Example 3, the coating solution for forming the absorbent film was applied to both sides of a glass substrate (manufactured by Matsunami Glass Industry Co., Ltd., S1127, 76 mm long × 26 mm wide × 1.0 to 1.2 mm thick) by immersion at a lifting speed of 5 cm / min. The resulting film was colorless, transparent, and uniform.

[0222] The glass substrate with the thin film was dried at 130°C for 1 hour, causing the film to change from colorless and transparent to a light brown, transparent, and uniform state. It was then placed in a heat treatment furnace and heated from room temperature to 450°C at a rate of 200°C / hour in an atmospheric atmosphere, and held at 450°C for 1 hour. This resulted in the formation of a 1.0 μm thick manganese oxide (Mn) film on the glass substrate. x O y (System) Ultraviolet absorbing film.

[0223] Through the above heat treatment, the film changed from colorless and transparent to dark brown. The resulting ultraviolet absorbing film was uniform, and no cracks or peeling were detected.

[0224] (Example 6)

[0225] Using the same method as in Example 5, manganese(II) nitrate hexahydrate (indicative formula: Mn(NO3)26H2O) was added at 3.5% by mass (equivalent to Mn2O3) to prepare a uniform, very light brown coating solution (manganese oxide-based (Mn)2O3) for forming an absorbent film. x O y 100g of a UV-absorbing coating was added to the coating solution, followed by the addition of 0.50g of methylene blue trihydrate as a colorant. The mixture was stirred at room temperature for 1 hour, thereby preparing a coating solution for forming an absorbent film containing a colorant. The resulting coating solution was a uniform liquid with a deep navy blue color.

[0226] Similar to Example 5, the coating liquid for forming the absorbent film was applied to both sides of a glass substrate (manufactured by Matsunami Glass Industry Co., Ltd., S1127, 76 mm long × 26 mm wide × 1.0 to 1.2 mm thick) by immersion at a lifting speed of 5 cm / min. The resulting film was a blue, transparent, and uniform film.

[0227] Similar to Example 5, the glass substrate with the thin film was dried at 130°C for 1 hour, causing the film to change from a clear blue to a uniform, light brownish-blue transparent state. It was then placed in a heat treatment furnace and heated from room temperature to 450°C at a rate of 200°C / hour in an atmospheric atmosphere, and held at 450°C for 1 hour. This resulted in the formation of a 1.0 μm thick manganese oxide (MnO2) film on the glass substrate. x O y (System) Ultraviolet absorbing film.

[0228] Through the above heat treatment, the film changed from blue and transparent immediately after coating to dark brown. The resulting ultraviolet absorbing film was uniform, and no cracks or peeling were detected.

[0229] When the above-mentioned coating liquid containing the colorant is applied to the edge of the lens, a blue transparent coating film can be easily formed, and the presence or absence of the coating film can be easily confirmed with the naked eye. In addition, it is also easy to confirm whether there is a trace amount of coating liquid adhering to the incident and exit surfaces of the lens where the adhesion of the coating liquid is restricted.

[0230] Figure 13 The graph shows two transmittance curves: the transmittance curve (dashed line) of the coating film after the absorber film forming coating liquid obtained in Example 5 is applied to a glass slide and dried at 130°C for 1 hour; and the transmittance curve (solid line) of the coating film after the absorber film forming coating liquid containing colorant obtained in Example 6 is applied to a glass slide and dried at 130°C for 1 hour.

[0231] Depend on Figure 13 It can be seen that the coating liquid obtained in Example 6 has improved visibility due to the presence of a colorant, which reduces the transmittance in the visible light region.

[0232] Figure 14 The graph shows two transmittance curves: the transmittance curve (dashed line) of the coating film obtained by coating a glass slide with the absorber film forming coating liquid obtained in Example 5, drying it at 130°C for 1 hour, and then performing heat treatment; and the transmittance curve (solid line) of the coating film obtained by coating a glass slide with the absorber film forming coating liquid containing the colorant obtained in Example 6, drying it at 130°C for 1 hour, and then performing heat treatment.

[0233] like Figure 14 As shown, for any dark brown coating film obtained by coating a glass slide with the colorant-free coating liquid obtained in Example 5 and the colorant-containing coating liquid obtained in Example 6, and then drying and heat-treating them, since they exhibit equal transmittance, the transmittance of the coating film obtained after heat treatment is not affected even if the colorant in the coating liquid for forming the absorption film is present.

[0234] Figure 15 This is a graph showing the transmittance curve (dashed line) when the coating liquid for forming the absorption film obtained in Example 5 is added to an acrylic resin measuring cell with an optical path length of 10 mm, and the transmittance curve (solid line) when the coating liquid for forming the absorption film containing the colorant obtained in Example 6 is added to an acrylic resin measuring cell with an optical path length of 10 mm. Figure 15 In Example 6, the transmittance of the coating liquid for forming the absorber film containing the colorant was essentially 0% in the entire visible light region, and the transmittance curve was essentially coincident with the horizontal axis.

[0235] Depend on Figure 15 It can be seen that, because the thickness of the object being measured is greater than... Figure 13 In Example 6, the coating film measured in the experiment more clearly demonstrated the effect of the colorant in the coating liquid on reducing the transmittance (improving visibility) in the visible light region.

[0236] (Example 7)

[0237] like Figure 5 As shown, four UV-LED chips (emission wavelength: 395nm) D, each 1mm long and 1mm wide, are arranged adjacently on substrate B as light sources. A first lens L1, a second lens L2, and a third lens L3 are arranged in the order of UV-LED side (light emission side) and light irradiation side to form an optical unit.

[0238] like Figure 5 As shown, the first lens L1, the second lens L2, and the third lens K3 were all coated with the ultraviolet absorbing coating prepared in Example 3 along their entire edges. They were then dried at 100°C for 1 hour and then placed in a heat treatment furnace. The temperature was increased from room temperature to 450°C at a rate of 200°C / hour in an atmospheric atmosphere and held at 450°C for 1 hour, thereby forming a manganese oxide-based ultraviolet absorbing film with a thickness of 1.5 μm on the edges.

[0239] Next, as Figure 6 As shown, a light illumination device (peripheral exposure light source device) was fabricated by arranging the 25 optical units described above in a 5×5 planar configuration.

[0240] like Figure 16 As briefly shown in (a), the peripheral portion of a semiconductor silicon wafer 1, which is coated with a photoresist film 1a with a thickness of 3 μm on the entire main surface, is exposed (peripheral exposure) using the above-mentioned light irradiation device under a cumulative light intensity of 25 mJ, and then the unwanted photoresist film on the periphery of the wafer is removed using a reagent.

[0241] In conducting the aforementioned exposure of the surrounding area, on the one hand, it is hoped that from Figure 16 (a) The edge (end) of the wafer 1 shown is where the resist film 1a is removed as much as possible, while on the other hand, it is desirable to maximize the usable area of ​​the resist film 1a. Therefore, in the region near the outer periphery of the silicon wafer 1, such as Figure 16 As briefly shown in (b), for resist 1a, the ideal state is to remove it as much as possible at a right angle in a way that makes the edge portion E sharp (in a steep manner).

[0242] In comparison, such as Figure 16As briefly shown in (c), for the silicon wafer 1 obtained by the above peripheral exposure process, the photoresist film is removed in such a way that the ends become sharp (in a steeply rising manner), and the collapse width d (the lateral width of the portion formed by the inclined portion) of the edge portion E is 31 μm (about 10 times the film thickness).

[0243] The photoresist film on the periphery of a semiconductor silicon wafer was exposed by using the above-mentioned light irradiation device continuously for 5000 hours. For the obtained silicon wafer, the photoresist film was removed in a way that sharpened the ends (in a steep upward manner), and the collapse edge width d was 30 μm, which was the same as before continuous use.

[0244] (Comparative Example 2)

[0245] In Example 7, the first lens, the second lens, and the third lens forming the optical unit are all lenses without ultraviolet absorption films. Otherwise, the optical unit is formed in the same manner as in Example 7. Then, in the same manner as in Example 7, 25 of the optical units are arranged in a planar configuration of 5 x 5 units, thereby creating a light irradiation device (peripheral exposure light source device).

[0246] Using the same light irradiation device as in Example 5, the peripheral portion of a semiconductor silicon wafer with a photoresist film of 3 μm thickness coated on the entire main surface was exposed (peripheral exposure) under a cumulative light intensity of 25 mJ. Then, the unwanted photoresist film on the periphery of the wafer was removed using a reagent.

[0247] like Figure 16 As briefly shown in (d), the silicon wafer obtained by the above treatment is formed by producing a gently sloping collapsed edge E at the edge of the photoresist film 1a and removing it, wherein the width of the collapsed edge d is 120 μm (40 times the film thickness).

[0248] For silicon wafers, since the periphery is retained during processing, if a resist film is also coated on the periphery of the wafer, the resist film will peel off during wafer processing, resulting in particles and a decrease in yield. Therefore, it is desirable to remove the unwanted resist film from the periphery of the wafer in advance.

[0249] Therefore, when removing the resist film at the periphery of the silicon wafer, from the viewpoint of suppressing the generation of the aforementioned particles, it is desirable to remove the resist film over as large an area as possible from the edge (end) of the silicon wafer. On the other hand, it is desirable to maximize the area where the resist film can be used. Therefore, in the area near the outer periphery of the silicon wafer, it is required to remove the resist film in a way that the edge portion becomes sharp (in a steeply rising manner).

[0250] However, when using light irradiation devices to remove the resist film, stray light generated by optical elements such as lenses mixes with the original exposure light, making the edges of the resist film prone to flat, sloping collapse.

[0251] As can be seen, the light irradiation device obtained in Example 7 includes an optical element or optical unit having the ultraviolet absorption film of the present invention, and therefore can not only highly suppress the generation of stray light, but also exhibit excellent durability.

[0252] On the other hand, it can be seen that the light irradiation device obtained in Comparative Example 2 does not contain an optical element or optical unit having the ultraviolet absorption film of the present invention, and therefore cannot suppress the generation of stray light, resulting in edge collapse at the edge of the resist film.

[0253] Industrial applicability

[0254] According to the present invention, an ultraviolet absorbing coating can be provided that can form a film that highly suppresses stray light generation and exhibits excellent durability in a thin film state. Furthermore, an ultraviolet absorbing film and a light absorbing film formed from the ultraviolet absorbing coating, an optical element obtained by forming the ultraviolet absorbing film on the surface, an optical unit having the optical element, and a light irradiation device having the optical unit can also be provided.

Claims

1. An optical element for an ultraviolet irradiation device, having an ultraviolet absorbing film on its edge or periphery, the ultraviolet absorbing film containing an oxide of one or more transition metals selected from Cr, Mn and Ni, wherein the content of the oxide of the aforementioned transition metal is 20 to 100 by mass.

2. The optical element for the ultraviolet irradiation device according to claim 1, wherein, The ultraviolet-absorbing film also contains silicon oxide or aluminum oxide.

3. The optical element for the ultraviolet irradiation device according to claim 1 or 2, wherein, The thickness of the ultraviolet absorbing film is less than 50 μm.

4. An optical element for an ultraviolet irradiation device, having a light-absorbing film at its edge or periphery, the light-absorbing film comprising a laminate, the laminate being a laminate of an ultraviolet absorbing film and an absorbing film that absorbs at least visible light or infrared light, the ultraviolet absorbing film containing an oxide of one or more transition metals selected from Cr, Mn and Ni, and the content of the oxide of the aforementioned transition metal is 20 to 100% by mass.

5. An optical unit for an ultraviolet irradiation device, comprising the optical element for an ultraviolet irradiation device as described in any one of claims 1 to 4.

6. An ultraviolet irradiation device having the optical unit for an ultraviolet irradiation device as described in claim 5.

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