CN117143474A

CN117143474A - Ultraviolet-absorbing paint, ultraviolet-absorbing film, light-absorbing film, optical element, optical unit, and light irradiation device

Info

Publication number: CN117143474A
Application number: CN202310919761.6A
Authority: CN
Inventors: 小川信一
Original assignee: Hoya Corp
Current assignee: Hoya Corp
Priority date: 2015-09-30
Filing date: 2016-09-30
Publication date: 2023-12-01
Also published as: TW201730290A; JP2017066381A; CN106947307A; KR20170038682A; TWI766845B; JP6987491B2

Abstract

The application provides an ultraviolet absorbing paint capable of forming a coating film which can highly inhibit stray light generation in a film state and can exert 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, and the oxide precursor of the transition metal is preferably a metal salt, a metal acid salt or an organic metal compound of one or more transition metals selected from Ti, V, cr, mn, fe, co, ni, cu, zn and Ce.

Description

Ultraviolet-absorbing paint, ultraviolet-absorbing film, light-absorbing film, optical element, optical unit, and light irradiation device

The present application is a divisional application of application publication number 201610874668.8, application publication number 2016, 9 and 30, and application publication number "ultraviolet absorbing paint, ultraviolet absorbing film, light absorbing film, optical element, optical unit, and light irradiation device".

Technical Field

The present application relates to an ultraviolet absorbing paint, an ultraviolet absorbing film, a light absorbing film, an optical element, an optical unit, and a light irradiation device.

Background

In an optical element such as a lens or a prism that is generally used in an optical instrument such as a camera or a microscope, since incident light to the optical element enters from a peripheral portion such as a ridge line of the optical element or an edge of the lens (a side surface of the lens), or the incident light is reflected on an inner surface such as an edge, stray light (Stray light) is generated, and the Stray light is mixed into the original irradiation light, and thus reflection flare, ghost, or the like is generated in an imaged image, and optical characteristics of the optical instrument are reduced.

In order to prevent the stray light, it is known to apply a black paint having an inner surface reflection preventing function to peripheral portions such as ridges and edges of an optical element to form a coating film of the black paint.

As the black paint having the function of preventing internal reflection, for example, a paint containing a metal oxide such as iron oxide, carbon black, a binder resin, a phthalocyanine compound, and a dispersant and a solvent containing a polymer dispersant has been proposed (see patent document 1 (japanese unexamined patent publication No. 2014-21231)).

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2014-21231

Disclosure of Invention

Problems to be solved by the invention

The black paint described in patent document 1 is a paint containing metal oxide particles and carbon black particles as light absorbing components, and is formed by dispersing the particles in a vehicle (binder resin and solvent), but has the following problems: not only the dispersion treatment of the particles is laborious and difficult to prepare simply, but also the particles are likely to be agglomerated and settled after the preparation to become uneven, resulting in a short pot life (pot life).

In addition, the conventional antireflective coating material such as the black coating material described in patent document 1 is intended for visible light, infrared light, or the like, and is basically used in an environment where the light intensity is not so strong, whereas in recent years, there is a tendency to use ultraviolet light having a high light intensity, so that stray light as an absorption object also becomes light having a large light energy and a strong light quantity.

When a coating film is formed on the surface of an optical element using the black paint described in patent document 1, although the solvent evaporates and disappears, organic components such as a binder resin and a dispersant remain, and therefore, the organic components deteriorate when ultraviolet light is incident on the optical element, and carbon black is also a carbonaceous material, and therefore, carbon black also easily deteriorates when high-intensity ultraviolet light is incident.

When the intensity of the incident light is high, degradation of the binder resin, the dispersant, and the like is promoted, and not only cracking and peeling of the coating film but also degradation of the carbon black and easy discoloration are caused.

For example, as an ultraviolet LED (UV-LED) as a curing light source for an ultraviolet curing resin or an ultraviolet curing ink, an LED which emits ultraviolet light with a wavelength of 365nm and 1W by supplying 3W power to an LED chip with a square of 1mm is used, and in this case, the irradiation light amount reaches 1W/mm ² This corresponds to 30,000 ～ 50,000 times the amount of ultraviolet light contained in sunlight. Therefore, a black paint having an inner surface reflection preventing function used for such a light source device is required to have resistance to strong ultraviolet rays.

Further, since 2W of the 3W power supplied from the ultraviolet LED is converted into heat energy to raise the temperature of the LED chip itself, the black paint having an inner surface reflection preventing function is required to have heat (temperature) resistance in addition to ultraviolet linearity resistance.

In order to solve the above technical problems, the present inventors have studied and have conceived to form an ultraviolet absorbing film containing no organic component as the coating film.

As a material for forming such an ultraviolet absorbing film, a colored low-melting glass or a low-melting glass containing an inorganic pigment is conceivable, but in the case of forming a coating film using these materials, the thickness of the coating film is as thick as, for example, several hundred μm, and in contrast, the machining tolerance of an optical element such as a lens is about ±0.05 to 0.10mm (50 to 100 μm), and when the coating film becomes thick, it cannot be taken into a given position, and correction is difficult.

In addition, if the difference between the coefficient of thermal expansion of the low-melting glass and the coefficient of thermal expansion of the optical element such as a lens or a prism is not controlled within a certain range, cracks occur in the optical element or the low-melting glass layer (coating film), or peeling occurs in the low-melting glass layer, so that it is difficult to continue using the optical device having the optical element.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an ultraviolet-absorbing paint capable of forming a coating film which is highly suppressed in the generation of stray light in a thin film state and which can exhibit excellent durability, and also to provide an ultraviolet-absorbing film, a light-absorbing film, an optical element, an optical unit, and a light irradiation device.

Means for solving the problems

The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that the above technical problems can be solved by an ultraviolet absorbing coating material containing an oxide precursor of one or more transition metals selected from Ti, V, cr, mn, fe, co, ni, cu, zn and Ce, and have completed the present invention based on the findings.

Namely, the invention provides the following technical scheme:

(1) An ultraviolet absorbing coating material comprising an oxide precursor of one or more transition metals selected from Ti, V, cr, mn, fe, co, ni, cu, zn and Ce.

(2) The ultraviolet absorbing paint according to the above (1), wherein the oxide precursor of the transition metal is a metal salt, a metal acid salt or an organic metal compound of one or more transition metals selected from Ti, V, cr, mn, fe, co, ni, cu, zn and Ce.

(3) The ultraviolet absorbing paint according to the above (1) or (2), wherein the ultraviolet absorbing paint contains 0.5 to 20.0 mass% of an oxide precursor of the transition metal in terms of transition metal oxide.

(4) The ultraviolet absorbing paint according to any one of (1) to (3), which further contains at least one member selected from the group consisting of a silicon oxide precursor and an aluminum oxide precursor.

(5) The ultraviolet absorbing paint according to any one of (1) to (4), which further comprises a colorant.

(6) An ultraviolet absorbing film comprising an oxide of one or more transition metals selected from Ti, V, cr, mn, fe, co, ni, cu, zn and Ce.

(7) The ultraviolet absorbing film according to the above (6), further comprising a silicon oxide or an aluminum oxide.

(8) The ultraviolet absorbing film according to the above (6) or (7), wherein the oxide of the transition metal is contained in an amount of 20 to 100% by mass.

(9) The ultraviolet absorbing film according to any one of (6) to (8), wherein the film thickness is 50 μm or less.

(10) A light-absorbing film comprising a laminate of the ultraviolet-absorbing film according to any one of (6) to (9) above and an absorbing film that absorbs at least visible light or infrared light.

(11) An optical element comprising the ultraviolet absorbing film according to any one of (6) to (9) above or the light absorbing film according to (10) above on a surface thereof.

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

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

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, an ultraviolet-absorbing paint capable of forming a coating film that highly suppresses the generation of stray light in a thin film state and exhibits excellent durability can be provided, and an ultraviolet-absorbing film, a light-absorbing film, an optical element, an optical unit, and a light irradiation device can be provided.

Drawings

Fig. 1 is a schematic diagram showing an example of an embodiment of a conventional optical element (fig. 1 (a)) and a schematic diagram showing an example of an embodiment of an optical element of the present invention (fig. 1 (b)).

Fig. 2 is a schematic diagram showing an example of an embodiment of the optical element of the present invention.

Fig. 3 is a schematic diagram showing an example of an embodiment of the optical element of the present invention.

Fig. 4 is a schematic diagram showing an example of an embodiment of the optical element of the present invention.

Fig. 5 is a schematic diagram showing an example of an embodiment of the optical unit of the present invention.

Fig. 6 is a schematic diagram showing an example of an embodiment of the light irradiation device of the present invention.

FIG. 7 shows the Fe-bearing alloy obtained in example 1 _x O _y Is a graph of transmittance curve of the substrate of the ultraviolet absorbing film.

Fig. 8 is a schematic diagram for explaining an evaluation method of the ultraviolet absorption effect.

Fig. 9 is a schematic diagram for explaining a method of evaluating durability of the ultraviolet absorbing film.

FIG. 10 is a view showing the composition obtained in example 2 with chromium oxide (Cr _x O _y )-SiO ₂ Is a graph of transmittance curve of the substrate of the ultraviolet absorbing film.

FIG. 11 is a view showing the composition obtained in example 3 with manganese oxide (Mn _x O _y ) Is a graph of transmittance curve of the substrate of the ultraviolet absorbing film.

FIG. 12 is a view showing the mixture obtained in example 4 with manganese oxide (Mn _x O _y )-SiO ₂ Is a graph of transmittance curve of the substrate of the ultraviolet absorbing film.

Fig. 13 is a graph showing transmittance curves of glass substrates obtained in example 5 and example 6, respectively, after the coating liquids for forming an absorption film were applied and dried.

Fig. 14 is a graph showing transmittance curves of glass substrates obtained in example 5 and example 6, respectively, after the coating liquids for forming an absorption film were applied and dried, and then heat-treated.

Fig. 15 is a graph showing the transmittance curves of the coating liquids for forming an absorption film obtained in example 5 and example 6.

Fig. 16 (a) to (d) are schematic views for explaining the shapes of the end portions of the silicon wafers obtained in example 7 and comparative example 2.

Detailed Description

First, the ultraviolet absorbing paint of the present application will be described.

The ultraviolet absorbing coating material of the present application contains an oxide precursor of one or more transition metals selected from Ti, V, cr, mn, fe, co, ni, cu, zn and Ce.

Hereinafter, in the present document, ultraviolet rays refer to light having a wavelength in the range of 250 to 420 nm. In the present document, the oxide precursor of the transition metal means a substance capable of forming an oxide of the transition metal by heating.

The ultraviolet absorbing paint of the present application contains an oxide precursor of at least one transition metal selected from Ti, V, cr, mn, fe, co, ni, cu, zn and Ce as an oxide precursor of a transition metal, and the transition metal is preferably at least one selected from Ti, cr, mn, fe, co, ni, cu and Zn, more preferably at least one selected from Ti, cr, mn, fe, cu and Zn.

The oxide precursor of the transition metal is preferably a metal salt, a metal acid salt, or an organometallic compound of the transition metal.

The metal salt of the transition metal is not particularly limited as long as it is capable of forming an oxide of the transition metal under heating and is soluble in the ultraviolet absorbing paint, and examples thereof include one or more metal salts selected from nitrate, sulfate, acetate, chloride, phosphate, carbonate, hydroxide, and the like.

The metal acid salt of the transition metal is not particularly limited as long as it can form an oxide of the transition metal under heating and can be dissolved in the ultraviolet absorbing coating material, and examples thereof include one or more selected from vanadate, chromate, dichromate, manganate, permanganate, ferrite, cobaltate, nickelate, cuprate, zincate, and cerite.

As the organometallic compound of the transition metal, an oxide of the transition metal is formed as long as it is heated and is soluble in ultraviolet raysThe line absorbing paint is not particularly limited, and examples thereof include: metal alkoxides, derivatives of metal alkoxides (e.g., organometallic compounds obtained by substituting a part or all of the alkoxy groups of metal alkoxides with ligands such as acetylacetone and ethyl acetoacetate), stearic acid soaps, lauric acid soaps, ricinoleic acid soaps, caprylic acid soaps, naphthenic acid soaps, montanic acid soaps, mountain soapsAt least one of acid soap, sebacic acid soap, myristic acid soap, palmitic acid soap, 12-hydroxystearic acid soap, etc.

The oxide of one or more transition metals selected from Ti, V, cr, mn, fe, co, ni, cu, zn and Ce exhibits strong absorptivity for light in the ultraviolet region.

In the ultraviolet light absorbing paint of the present application, since the ultraviolet light absorbing film containing the transition metal oxide can be formed on the surface of the object to be coated such as an optical element by applying the paint to the object to be coated such as an optical element and heating the paint, the occurrence of stray light can be highly suppressed in a thin film state even when the ultraviolet light absorbing paint is used for absorbing ultraviolet light in a device capable of outputting ultraviolet light having a large light energy with high intensity, and in addition, even when the ultraviolet light absorbing paint contains an organic component such as a solvent, the organic component can be removed by the above-mentioned heat treatment to form a uniform transition metal oxide film, and therefore, the obtained ultraviolet light absorbing film can suppress discoloration, peeling, disappearance, and the like of a coating film accompanying deterioration of the organic component even when ultraviolet light is irradiated for a long period of time, and excellent durability can be exhibited.

The ultraviolet absorbing coating material of the present application may further contain at least one member selected from the group consisting of a silicon oxide precursor and an aluminum oxide precursor.

In the present document, the silicon oxide precursor refers to a substance capable of forming silicon oxide by heating, and examples thereof include: tetraethoxysilane, tetramethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, or an oligomer or polysilazane formed from one or more of them.

In the present document, the aluminum oxide precursor means a substance capable of forming an aluminum oxide by heating, and examples thereof include at least one selected from aluminum alkoxides such as aluminum sec-butoxide and aluminum isobutanol, aluminum chelate compounds obtained by modifying a part or all of the alkoxy groups of the above aluminum alkoxides with a chelating agent such as acetylacetone and ethyl acetoacetate, aluminum soaps such as aluminum stearate, aluminum octoate and aluminum naphthenate, aluminum nitrate nonahydrate, aluminum chloride, aluminum polychloride, and the like.

The ultraviolet absorbing coating of the present application further contains at least one selected from the group consisting of a silicon oxide precursor and an aluminum oxide precursor, whereby a composite film of a transition metal oxide and a silicon oxide or an aluminum oxide can be easily formed at the time of forming an ultraviolet absorbing film, and the adhesion of the ultraviolet absorbing film obtained by applying the ultraviolet absorbing coating to an optical element can be improved by the composite film, whereby the ultraviolet absorbing film is less likely to be peeled off.

The ultraviolet absorbing paint of the present application may further contain a colorant.

When the ultraviolet-absorbing paint of the present application contains a colorant, the colorant is a colorant which is not gelled, or is precipitated as a raw material of an absorbing film, is stably dissolved or dispersed in the paint, has a light-absorbing ability for visible light, and is preferably a colorant which is disappeared by decomposition, volatilization, or the like at a temperature at which an oxide precursor of a transition metal contained in the ultraviolet-absorbing paint forms a metal oxide, or is capable of forming an inorganic oxide.

Examples of the colorant include dyes and pigments, and dyes are preferable. Dyes are preferred as the colorant from the viewpoint of easy dissolution in the paint, less tendency to cause aggregation, and the like.

In the case where the colorant is a dye, as long as the dye can be dissolved in an ultraviolet absorbing coating material to make the coating film visible, there are no particular restrictions, and examples thereof include dyes selected from methylene blue, triphenylmethane dyes (for example, malachite green), ice-dyeing dyes, azo dyes, acridine, aniline dyes (for example, nigrosine), indanthrene, eosin, congo red, indoline, phenazine derivative dyes (for example, neutral red), phenolphthalein, fuchsin, fluorescein, palatine, aniline violet (mauve), caramel, gardenia, anthocyanin dyes, anriton (annatto) dyes, capsicum dyes, safflower dyes, monas dyes, flavonoid dyes, cochineal dyes, amaranth (red No. 2), erythrone (red No. 3), induced red AC (Allura Red AC) (red No. 40), new carmine (New cocine) (red No. 102), fluoropink (Phloxine) (red 104), rose bengal (red No. 105), acid red (red No. 106), yellow (yellow No. 4), fast blue (yellow No. 35 f) and fast green (green blue No. 3).

In the case where the colorant is a pigment, the pigment is not particularly limited as long as it is a pigment which is less likely to cause aggregation and the like, and examples thereof include pigments selected from the group consisting of iron oxide red, ultramarine blue, prussian blue, carbon black, isoindolinone, isoindoline, azomethine, anthraquinone, anthrone, xanthene, pyrrolopyrrole dione, perylene, pyrene (perinone), quinacridone, indigoid, and diAnd one or more of oxazine, phthalocyanine, etc.

The ultraviolet absorbing film obtained from the ultraviolet absorbing paint of the present invention can highly suppress the generation of stray light even in a thin film state, but when the ultraviolet absorbing film to be obtained is thin, the thickness of the coating film formed at the time of application of the ultraviolet absorbing paint is also thin, and it is difficult to identify whether or not it is applied to a given portion, whether or not it is applied by a desired amount, whether or not it is attached to a non-coated surface such as an incident surface, an outgoing surface or the like of a lens. In the case where the ultraviolet-absorbing coating material is transparent, the identification of the coating film becomes more difficult, and although the ultraviolet-absorbing coating material is sometimes pre-colored by a transition metal oxide precursor or the like used, it is similarly difficult to identify the coating film when the degree of coloring is low and the thickness of the coating film becomes thin. Before the ultraviolet absorbing film is formed by drying and heat-treating the coating film, the coated coating film may be erroneously erased, but if the heating treatment is directly performed, the coating film is not easily removed by sintering on the surface of the optical element, and the yield of the product may be lowered.

When the ultraviolet-absorbing paint of the present invention further contains a colorant, the presence or absence of a coating film can be easily recognized at the time of coating, and the production efficiency of the optical element and the yield of the product can be easily improved.

When the ultraviolet-absorbing paint of the present invention contains a colorant, the colorant is contained in an increased proportion (i.e., the amount of the colorant added per the total amount of the ultraviolet-absorbing paint after the colorant is added) relative to the ultraviolet-absorbing paint, preferably in an amount of 0.005 to 20% by mass, more preferably in an amount of 0.01 to 10% by mass, and even more preferably in an amount of 0.05 to 5% by mass.

The ultraviolet absorbing coating material of the present invention may further contain a binder component or a solvent.

When the ultraviolet-absorbing coating material of the present invention contains a binder component or a solvent, the binder component or the solvent preferably disappears by decomposition, volatilization, or the like at a temperature at which the oxide precursor of the transition metal contained in the ultraviolet-absorbing coating material forms a metal oxide.

The binder component may be one or more selected from polyvinylpyrrolidone, polyethylene glycol, polyvinyl alcohol, hydroxyethyl cellulose, hydroxypropyl cellulose, polyvinyl acetate, chitosan, and the like.

By containing the binder component in the ultraviolet absorbing coating material of the present invention, the oxide precursor of the transition metal can be stably and uniformly applied to the substrate, and an ultraviolet absorbing film can be easily formed.

The binder may be appropriately selected according to the kind of the transition metal oxide precursor contained in the ultraviolet-absorbing paint, and for example, when the ultraviolet-absorbing paint contains a manganese oxide precursor as the transition metal oxide precursor, it is preferable to contain polyvinylpyrrolidone as the binder, and by containing polyvinylpyrrolidone as the binder, the manganese oxide precursor can be well dissolved in the ultraviolet-absorbing paint.

The solvent is preferably a solvent that disappears by decomposition, volatilization, or the like at a temperature at which the oxide precursor of the transition metal contained in the ultraviolet-absorbing coating material forms a metal oxide.

The solvent may be at least one selected from butanols such as methanol, ethanol, n-propanol, isopropanol, and n-butanol, 2-methoxyethanol, 2-ethoxyethanol, ethylene glycol, diethylene glycol, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, propionic acid, and butyric acid.

In the ultraviolet absorbing coating material of the present invention, the content of the oxide precursor of the transition metal is preferably 0.1 to 20.0 mass%, more preferably 0.5 to 15.0 mass%, and even more preferably 1.0 to 10.0 mass% in terms of oxide of each transition metal.

In the ultraviolet absorbing coating material of the present invention, the occurrence of cracks and peeling can be favorably suppressed when forming an ultraviolet absorbing film by setting the content ratio of the transition metal oxide precursor in the above range.

In general, when an inorganic oxide film is formed on a substrate using a metal oxide precursor, shrinkage is easily suppressed by bonding the substrate surface side of the inorganic oxide film formed with the substrate, whereas shrinkage is freely generated on the outer surface side of the inorganic oxide film, accompanied by a large volume shrinkage, and since the metal oxide film has a poor flexibility as compared with the organic film, cracking and peeling of the oxide film are easily generated by the stress generated by the volume shrinkage.

When the content of the transition metal oxide precursor is less than 0.1 mass%, the film thickness of the obtained transition metal oxide film tends to be thin, and it is difficult to obtain the target absorption characteristics, and when the content of the transition metal oxide precursor exceeds 20.0 mass%, the film thickness of the obtained transition metal oxide film becomes thick, the stress tends to increase, and the cracking and peeling easily occur.

In the present document, the term "oxide of transition metal" when the transition metal is Ti refers to TiO when the transition metal is Ti in calculating the content ratio of transition metal ₂ When the transition metal is V, V is meant ₂ O ₅ When the transition metal is Cr, cr is referred to as Cr ₂ O ₃ When the transition metal is Mn, mn is meant to be ₂ O ₃ When the transition metal is Fe, this means Fe ₂ O ₃ 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, ceO when the transition metal is Ce ₂ 。

In the ultraviolet absorbing paint of the present application, by setting the content ratio of the transition metal to the above range, the ultraviolet absorbing film having a desired thickness can be easily formed while the transition metal is well dissolved.

When the ultraviolet absorbing coating material of the present application further contains one or more selected from the group consisting of a silicon oxide precursor and an aluminum oxide precursor, the total content of the oxide precursors of the transition metals converted to the oxides is preferably 1.0 to 30.0 mass%, more preferably 2.0 to 25.0 mass%, and even more preferably 3.0 to 20.0 mass% in terms of the oxides.

In the ultraviolet absorbing coating of the present application, the total content of one or more selected from the group consisting of the silicon oxide precursor and the aluminum oxide precursor is in the above range, so that the adhesion of the obtained ultraviolet absorbing film to the substrate can be improved, and the occurrence of the cracks and peeling can be easily suppressed.

In the present application, the oxide of the silicon oxide precursor in calculating the above-mentioned content ratio means SiO ₂ The oxide of the aluminum oxide precursor at the above content ratio is A1 ₂ O ₃ 。

The ultraviolet absorbing coating material of the present application can be easily prepared, for example, by dissolving the oxide precursor of the transition metal and, if necessary, at least one selected from the group consisting of a silicon oxide precursor and an aluminum oxide precursor in the presence of an appropriate binder, a solvent, or the like in a desired amount.

According to the present application, it is possible to provide an ultraviolet absorbing paint capable of forming a coating film that can highly suppress the occurrence of stray light in a thin film state and can exhibit excellent durability.

Next, the ultraviolet absorbing film of the present application will be described.

The ultraviolet absorbing film of the present application is characterized by containing an oxide of one or more transition metals selected from Ti, V, cr, mn, fe, co, ni, cu, zn and Ce.

The transition metal is preferably one or more selected from Ti, cr, mn, fe, co, ni, cu and Zn, more preferably one or more selected from Ti, cr, mn, fe, cu and Zn.

The transition metal generally has various valence states, and thus the oxide of the transition metal may be in various forms, and in the present document, the oxide of the transition metal means not only an oxide of a specific transition metal but also a form in which a plurality of oxides are mixed.

The ultraviolet absorbing film of the present invention may be an ultraviolet absorbing film in which two or more kinds of oxides of transition metals are mixed.

Since the ultraviolet absorbing film of the present invention contains the above-mentioned transition metal oxide, even when used for absorbing ultraviolet rays in a device capable of outputting ultraviolet light having a large light energy at a high intensity, the occurrence of stray light can be highly suppressed in a thin film state, and discoloration, peeling, disappearance, and the like of a coating film can be suppressed even when ultraviolet rays are irradiated for a long period of time, and excellent durability can be exhibited well.

The ultraviolet absorbing film of the present invention may further contain one or more kinds selected from the group consisting of silicon oxide and aluminum oxide, in addition to the oxide of the transition metal.

By further containing at least one selected from the group consisting of silicon oxide and aluminum oxide, the ultraviolet absorbing film of the present invention can form a composite film of a transition metal oxide and silicon oxide, aluminum oxide, or the like, and by using the composite film, adhesion to a substrate can be improved, and occurrence of the cracks and peeling can be easily suppressed.

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

The film thickness of the ultraviolet absorbing film of the present invention is preferably 50 μm or less, more preferably 25 μm or less, further preferably 10 μm or less, and still more preferably 5 μm or less.

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

In the case where the ultraviolet absorbing film of the present invention is provided on the surface of an optical element, particularly, since the optical element for an LED is often an element having a very small shape, the machining tolerance of the optical element is usually ±100 μm, and strictly speaking, ±50 μm. In order to accurately center the optical element, it is required that the ultraviolet absorbing film be a film-like film, and in the case of a configuration in which a plurality of various optical elements are arranged, it is also required that the ultraviolet absorbing film be a film-like film in order to suppress positional displacement of each optical element, but in general, the ultraviolet absorbing performance of the ultraviolet absorbing film is also lowered when the film is formed.

Since the ultraviolet absorbing film of the present application contains an oxide of a specific transition metal, in an apparatus capable of outputting ultraviolet light having a large light energy at a high intensity, even when the film is used for absorbing ultraviolet light, the generation of stray light can be suppressed to a high degree in a thin film form.

In the present document, the film thickness of the ultraviolet absorbing film is a value obtained by measuring the total thickness of the substrate and the ultraviolet absorbing film and the thickness of the substrate by using a micrometer (MDH-25M manufactured by Mitutoyo corporation), respectively, and by the difference between the two.

In the ultraviolet absorbing film of the present application, the Optical Density (OD) of the ultraviolet absorbing film is preferably 1 or more, more preferably 2 or more, and still more preferably 3 or more.

By setting the Optical Density (OD) within the above range, in an apparatus capable of outputting ultraviolet light having a large light energy at a high intensity, even when used for absorbing ultraviolet light, the generation of stray light can be highly suppressed in a thin film form.

In the present document, the Optical Density (OD) is a value measured when irradiated with irradiation light including light of a wavelength or a wavelength range to be absorbed, using an ultraviolet-visible near-infrared spectrophotometer (U-4100 manufactured by hitachi corporation).

The ultraviolet absorbing film of the present invention is desirably free from cracks (fissures) when observed with the naked eye.

By making the ultraviolet absorbing film of the present invention free from cracks (fissures), peeling of the ultraviolet absorbing film from an object to be film-formed such as an optical element can be easily suppressed, formation of scraps or the like can be easily suppressed, and a desired stray light absorbing effect can be easily obtained.

In the ultraviolet absorbing film of the present invention, among the optical elements such as lenses, prisms, and barrels, the surface of the optical element other than the original optical path is preferably provided, and for example, the surface of the optical element other than the entrance surface and exit surface of the lens such as the edge of the lens, the inner surface of the barrel, and the like may be preferably provided.

By providing the ultraviolet absorbing film of the present invention on the surface of the portion other than the original optical path in this way, in an apparatus capable of outputting ultraviolet light having a large light energy at a high intensity, even when used for absorbing ultraviolet light, the occurrence of stray light can be highly suppressed in a thin film form.

The ultraviolet absorbing film of the present invention can be preferably produced by using the ultraviolet absorbing paint of the present invention.

Examples of the method for producing the ultraviolet absorbing film of the present invention include: a method of applying the ultraviolet absorbing coating material of the present invention to a substrate (an object to be formed of an absorbing film) and forming a film by a sol-gel method.

Examples of the method for producing such an ultraviolet absorbing film include: the ultraviolet absorbing paint of the present invention is applied to a film-forming object by a brush, a spray, or a dipping method or a spin coating method, thereby forming a coating film of a desired thickness, and then drying and heating are appropriately performed. The temperature during the heat treatment is preferably 300 to 1000 ℃, and the treatment time during the heat treatment is preferably 1 minute to 12 hours.

By the above method, a target metal oxide film (ultraviolet absorbing film) can be formed.

In the ultraviolet absorbing film of the present invention, in an apparatus capable of outputting ultraviolet light having a large light energy at a high intensity, even when used for absorbing ultraviolet light, the occurrence of stray light can be highly suppressed in a thin film form.

Next, the light absorbing film of the present invention will be described.

The light absorbing film of the present invention is characterized by comprising a laminate of the ultraviolet absorbing film of the present invention and an absorbing film that absorbs at least visible light or infrared light.

The ultraviolet absorbing film of the present invention is described in detail above.

In the light absorbing film of the present invention, the absorbing film that absorbs visible light or infrared light may be provided on the ultraviolet absorbing film of the present invention by applying a known coating agent that can form the absorbing film of visible light or infrared light.

Examples of the coating agent include one or more types selected from the group consisting of an anti-surface reflection coating (model CS-37, manufactured by CANON CHEMICALS Co., ltd.), and a near infrared ray shielding material (model YMF-02A, manufactured by Sumitomo Metal mine Co., ltd.).

The light absorbing film of the present invention may be provided so that the ultraviolet absorbing film is positioned on the light incident side, or may be provided so that the absorbing film that absorbs visible light or infrared light is positioned on the light incident side.

The light absorbing film of the present invention is provided with an absorbing film that absorbs at least either visible light or infrared light, and thus can highly suppress the generation of stray light even when applied to a light emitting body that emits light including ultraviolet light, visible light, or infrared light having a large light energy.

Examples of the light-emitting body that emits light including ultraviolet light, visible light, and infrared light having a large light energy include: a mercury xenon lamp, a metal halide lamp, or other lamps, an ultraviolet LED (UV-LED), a white LED, a light-emitting element such as an LED unit in which a multi-wavelength LED is mounted on a substrate in a mixed manner, or the like.

Next, an optical element of the present invention will be described.

The optical element of the present invention is characterized by having the ultraviolet absorbing film or the light absorbing film of the present invention on the surface thereof.

The ultraviolet light absorbing film or the light absorbing film of the present invention is described in detail above. In the optical element of the present invention, the position and method for forming the ultraviolet absorbing film are also described in detail above.

The optical element of the present invention may be one or more selected from the group consisting of lenses, prisms, barrels, mirrors, and the like, which are generally called optical elements, and the like.

Hereinafter, an optical element of the present invention will be described with reference to specific examples.

Fig. 1 is a schematic view (fig. 1 (a)) showing a cross section of a conventional optical element (lenticular lens) L as an optical element and a schematic view (fig. 1 (b)) showing a cross section of an optical element (lenticular lens) L of the present invention as an example of an optical element, and generally, as shown in fig. 1 (a), a part of ultraviolet light I entering an optical surface is incident from an edge (side surface) of a lens to be reflected on an inner wall surface of the lens edge to generate stray light S, but as shown in fig. 1 (b), since the optical element of the present invention has an ultraviolet absorbing film a at the edge of the lenticular lens L, ultraviolet light can be effectively absorbed at the edge of the lens, and generation of stray light S can be suppressed (for convenience, stray light S generated when the lenticular lens L does not have the ultraviolet absorbing film a is shown by a dotted line in fig. 1 (b)).

Although a biconvex lens is illustrated as the lens L in fig. 1, the lens L may be replaced with any one of a biconcave lens, a plano-convex lens, and a plano-concave lens, and in this case, the ultraviolet absorbing film a is provided at the edge of each lens.

Fig. 2 is a schematic view showing a cross section of a meniscus lens as an example of an optical element of the present invention, and in general, as shown in fig. 2, a part of ultraviolet light I entering an optical surface enters from an edge (side surface) of the lens or is reflected on an inner wall surface of the lens edge to generate stray light S, but since the optical element of the present invention has an ultraviolet absorbing film a at the edge of the lens L, ultraviolet light can be effectively absorbed at the lens edge, and generation of stray light can be suppressed (for convenience, stray light S generated when the meniscus lens L does not have the ultraviolet absorbing film a is shown by a dotted line in fig. 2).

In the meniscus lens shown in fig. 2, a mask for blocking light is usually provided on the plane portion of the incident surface in order to selectively allow light to enter from the concave portion of the incident surface, but in the case where the mask is not provided, stray light S is similarly generated due to light entering from the plane portion of the incident surface. Therefore, in the example shown in fig. 2, the ultraviolet absorbing film a is also provided on the plane portion of the incident surface, and by effectively absorbing ultraviolet light on the plane portion on the incident surface side, it is possible to suppress the generation of stray light while doubling as the mask.

Fig. 3 is a schematic view showing a cross section of a lens barrel as an example of an optical element of the present invention, and generally, as shown in fig. 3, a part of incident light I incident on a lens barrel surface is reflected on an inner wall surface of the lens barrel to generate stray light S, but since the lens barrel shown in fig. 3 has an ultraviolet absorbing film a on an inner wall surface of the lens barrel T, light can be effectively absorbed on the inner wall surface, and generation of stray light can be suppressed (for convenience, stray light S generated when the lens barrel T does not have the ultraviolet absorbing film a is shown by a broken line in fig. 3).

Conventionally, a lens barrel has been subjected to a black alumina film process in which a cavity formed by subjecting an inner wall surface to an alumina film treatment is impregnated with a black dye, but since the black dye is an organic substance, when light of a short wavelength such as ultraviolet light or light of a high intensity is irradiated into the lens barrel, the dye is decomposed and discolored, and stray light is easily generated. In contrast, the optical element of the present invention has the ultraviolet absorbing film of the present invention containing the transition metal oxide, and therefore can exhibit excellent durability even for ultraviolet light having a large intensity, and can suppress the generation of stray light.

Fig. 4 is a schematic view showing a cross section of a mirror box as an example of an optical element of the present invention, and in general, as shown in fig. 4, in the mirror box, ultraviolet light from an entrance port of the mirror box is emitted from an exit port, and a part of the incident ultraviolet light I is reflected on an inner wall surface of the mirror box to generate stray light S. In contrast, in the mirror box MB shown in fig. 4, since the ultraviolet absorbing film a is provided on the inner wall surface of the mirror box MB except the inner wall surface of the reflecting mirror portion, the edge of the entrance port or the exit port, ultraviolet light on the inner surface other than these reflecting mirror surfaces can be effectively absorbed, and the generation of stray light can be suppressed (for convenience, stray light S generated when the mirror box MB does not have the ultraviolet absorbing film a is shown by a broken line in fig. 4).

Although not shown, the optical element of the present invention may be an optical element in which the ultraviolet absorbing film of the present invention is provided on a surface of the prism other than the incident surface, the exit surface, and the reflection surface.

In the optical element of the present invention, in the device capable of outputting ultraviolet light having a large light energy at a high intensity, even when used for absorbing ultraviolet light, 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.

Next, an optical unit of the present invention will be described.

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

Details of the optical element of the present invention are described above.

The optical unit of the present invention is not particularly limited as long as it has the optical element of the present invention.

The optical unit of the present invention generally has an optical element and a light source.

The light source is not particularly limited as long as it can radiate light including ultraviolet light, and examples thereof include at least one selected from ultraviolet LEDs (UV-LEDs), discharge lamps such as short arc lamps and long arc lamps.

Fig. 5 is a diagram illustrating an optical unit of the present invention, the upper diagram of fig. 5 is a schematic view seen from the upper side, and the lower diagram of fig. 5 is a schematic cross-sectional view seen from the side.

The optical unit shown in fig. 5 is formed by providing 4 ultraviolet LEDs (LED chips) D on a substrate B, and providing a first lens Ll, a second lens L2, and a third lens L3 in this order from the ultraviolet LED side (irradiation side) to the emission side, and the edges of the first lens Ll, the second lens L2, and the third lens L3 have the ultraviolet absorbing film of the present invention.

The optical unit of the present invention can highly suppress the generation of stray light and simultaneously perform light irradiation even when used in an apparatus capable of outputting ultraviolet light having a large light energy at a high intensity, when used for absorbing visible light or infrared light while absorbing ultraviolet light.

Next, a light irradiation device of the present invention will be described.

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

Details of the optical unit of the present invention are described above.

Examples of the light irradiation device of the present invention include: a spot type ultraviolet light source, a line type ultraviolet light source, a surface type ultraviolet light source, a light guide type ultraviolet light source, a peripheral exposure light source device, and the like.

The light irradiation device of the present invention includes 1 or more optical units of the present invention, and generally includes 2 or more optical units of the present invention.

Fig. 6 is a plan view illustrating a light irradiation apparatus according to the present invention, and in the example shown in fig. 6, the light irradiation apparatus includes 25 optical units U shown in fig. 5, and these optical units can cooperate to irradiate an object to be irradiated with light when in use.

Even if the light irradiation device of the present invention is a device capable of outputting ultraviolet light having a large light energy at a high intensity, or a device capable of outputting visible light or infrared light at the same time as ultraviolet light, the optical unit of the present invention can highly suppress the generation of stray light, and can highly suppress the mixing of stray light into the original irradiation light.

Examples (example)

The present invention will be further described with reference to examples and comparative examples, but the present invention is not limited to the examples.

Example 1

Adding ethylene glycol (shown formula: C) into glass container ₂ H ₄ (OH) ₂ ) 19.4g and iron (III) nitrate nonahydrate (formula: fe (NO) ₃ ) ₃ 9H ₂ O) 12.6g, iron (III) nitrate nonahydrate was dissolved in ethylene glycol and then isopropyl alcohol (formula: CH (CH) ₃ CH(OH)CH ₃ ) 68.0g, and further stirred at room temperature for 2 hours, thereby preparing a brown transparent and uniform coating liquid (Fe _x O _y Ultraviolet absorbing paint) 100g.

When the coating liquid is subjected to heat treatment to form all the iron nitrate into oxide, the solid content in the obtained coating liquid for forming an absorption film is converted into Fe ₂ O ₃ 2.5 mass%.

The absorbing film forming coating liquid was applied to both sides of a glass sheet substrate (S1127, manufactured by Song Nitro Co., ltd., length 76 mm. Times.width 26 mm. Times.thickness 1.0 to 1.2 mm) by dipping at a lifting speed of 30 cm/min. The resulting film was a transparent uniform film exhibiting a pale orange color.

The glass sheet with the film is providedThe substrate was dried at 70℃for 1 hour, then placed in a heat treatment furnace, and heated from room temperature to 500℃at 200℃per hour in an atmosphere and held at 500℃for 1 hour, whereby iron oxide (Fe) was formed on the glass sheet substrate _x O _y ) Is an ultraviolet absorbing film. The thickness of the obtained ultraviolet absorbing film is less than 1 μm.

By the above heat treatment, the film changed from light orange to dark orange, and the obtained ultraviolet absorbing film was uniform, and the occurrence of cracks and peeling was not confirmed.

The transmittance curves of the obtained substrate with and without the ultraviolet absorbing film are shown in fig. 7.

The broken line of FIG. 7 is the transmittance curve of the substrate alone (without the ultraviolet absorbing film), and the solid line with Fe _x O _y The transmittance curve of the substrate of the ultraviolet absorbing film shows that the absorption by the iron oxide constituting the ultraviolet absorbing film occurs in the ultraviolet region of 250 to 420nm, and therefore the transmittance of the solid line (having the ultraviolet absorbing film) is highly suppressed in the entire ultraviolet region, compared with the broken line (the substrate alone).

(evaluation of ultraviolet absorption Effect)

The absorbing film forming coating liquid was applied to the polished surface at a lifting speed of 30 cm/min by dipping in a state where the optical polished surface of the quartz glass substrate (20 mm long. Times.50 mm wide. Times.2 mm thick, 20mm long. Times.50 mm wide) was used as the main surface of the optical polished surface, and the other main surface was #1000 polished surface) was masked with a masking tape.

The masking tape was peeled off from the quartz glass substrate with the film, dried at 70℃for 1 hour, then placed in a heat treatment furnace, heated from room temperature to 500℃at 200℃per hour, and held at 500℃for 1 hour, whereby iron oxide (Fe) was formed on the frosted surface of the quartz glass substrate _x O _y ) Is an ultraviolet absorbing film. The obtained iron oxide (Fe _x O _y ) The film thickness of the ultraviolet absorbing film is less than 1 μm.

As schematically shown in fig. 8, the intensity of light entering from the side surface (end surface) of the quartz glass substrate G on the main surface (ground surface W and optical grinding surface P) was measured using the obtained quartz glass substrate with the ultraviolet absorbing film (the upper diagram in fig. 8 is a schematic diagram showing the entire measurement system, and the lower diagram in fig. 8 is a schematic diagram in which a portion surrounded by a circle in the upper diagram is enlarged).

That is to say,

(1) The quartz glass substrate G (20 mm long by 50mm wide by 2mm thick, 20mm long by 50mm wide, the main surface of which is an optical polished surface P, and the other main surface of which is a #1000 polished surface W) before the formation of the ultraviolet absorbing film was disposed on the light receiver R having the light receiving portion LR so as to be disposed in the arrangement shown in FIG. 8, and the output of the UV-LED light source (peak wavelength 365 nm) was adjusted so that the display value of the light receiving portion LR was 10.00mW/cm when the ultraviolet light L was irradiated horizontally from the side surface on the end portion side of the quartz glass substrate ² ，

(2) Next, as shown in fig. 8, the quartz glass substrate was changed to a quartz glass substrate G having a frosted surface W provided with an ultraviolet absorbing film C and an optical polished surface P as main surfaces (a main surface 20mm long by 50mm wide by 2mm thick, 20mm long by 50mm wide is an optical polished surface P, and the other main surface is a #1000 frosted surface W), and ultraviolet light L was irradiated horizontally on the end portion side of the quartz glass substrate in the same manner as described above,

(3) The incident light was internally reflected in the quartz glass substrate and absorbed by the ultraviolet absorbing film C, and the intensity I of the outgoing light emitted to the light receiving portion LR side was measured _l Intensity I relative to incident light _O Ratio ((I) _l /I _O )×100)。

As a result, when the quartz glass substrate on which the ultraviolet absorbing film was not formed was used, the intensity (I _l ) 10.00mW/cm ² In contrast, when the quartz glass substrate G on which the ultraviolet absorbing film C was formed was used, the intensity (I _l ) Is 0.20mW/cm ² Intensity I of outgoing light emitted to the light receiver R side _l Intensity I relative to the incident light _O Ratio ((I) _l /I _O ) X 100) was 2.0%.

(durability evaluation)

As shown in FIG. 9, for the same as described aboveThe same quartz glass substrate with ultraviolet absorbing film as that used in the evaluation of ultraviolet absorbing effect was used, and the incident angle was 90℃2000mW/cm from the frosted surface W side provided with the ultraviolet absorbing film C ² The ultraviolet absorbing film C did not crack or peel, nor did the transmittance change before and after ultraviolet irradiation, at an intensity of 5000 hours of incidence.

Example 2

In tetraethoxysilane (illustrative: si (C) ₂ H ₅ O) ₄ ) To a mixed solution of 23.6g and 18.9g of isopropyl alcohol, a mixed solution of 16.0g of 0.7 mass% aqueous hydrochloric acid and 18.9g of isopropyl alcohol was slowly added, and stirred for 2 hours, followed by addition of chromium (III) nitrate nonahydrate (formula: cr (NO) ₃ ) ₃ ·9H ₂ O) 22.6g, and further stirred for 2 hours, thereby preparing a coating liquid (chromium oxide-SiO ₂ Series (Cr) _x O _y -SiO ₂ System) UV-absorbing coating) 100g.

The coating liquid was subjected to heat treatment to thereby produce Cr in the whole of chromium (III) nitrate ₂ O ₃ SiO is formed by tetraethoxysilane ₂ The solid content in the obtained coating liquid for forming an absorption film contained 20 mol% of Cr ₂ O ₃ 80 mol% of SiO ₂ The solid content in the coating liquid (assuming that all oxides are formed by heat treatment) was converted to 20Cr ₂ O ₃ ·80SiO ₂ 11.1 mass%.

The coating liquid for forming an absorption film was applied to both sides of a glass sheet substrate (S1127, manufactured by Song Nitro Co., ltd., length 76 mm. Times. Width 26 mm. Times. Thickness 1.0 to 1.2 mm) by dipping at a lifting speed of 30 cm/min. The resulting film was a transparent uniform film exhibiting light navy.

The same conditions as in example 1 were employed, namely, the glass sheet substrate with the film was dried at 70℃and then placed in a heat treatment furnace, and the temperature was raised from room temperature to 500℃at 200℃per hour in an atmosphere and kept at 500℃for 1 hour, whereby chromium oxide-SiO was formed on the glass sheet substrate ₂ Series (Cr) _x O _y -SiO ₂ Is a UV absorbing film). The obtained chromium oxide-SiO ₂ Series (Cr) _x O _y -SiO ₂ The system) the thickness of the ultraviolet absorbing film is less than 1 μm.

By the above heat treatment, the film changed from light navy to dark green, and the obtained ultraviolet absorbing film was uniform, and the occurrence of cracks and peeling was not confirmed.

The transmittance curves of the obtained substrate with and without the ultraviolet absorbing film are shown in fig. 10.

The broken line of FIG. 10 is the transmittance curve of the substrate alone (without the ultraviolet absorbing film), and the solid line with Cr _x O _y -SiO ₂ The transmittance curve of the substrate having the ultraviolet absorbing film shows that the transmittance of the solid line (having the ultraviolet absorbing film) is highly suppressed in the entire ultraviolet region as compared with the broken line (the substrate alone) because the ultraviolet absorbing film is absorbed by the chromium oxide constituting the ultraviolet absorbing film in the ultraviolet region of 250 to 420 nm.

As a result of evaluating the ultraviolet absorption effect in the same manner as in example 1 using the above-mentioned coating liquid for forming an absorption film, when using the quartz glass substrate G on which the ultraviolet absorption film C was formed, the intensity (I _l ) Is 0.19mW/cm ² Intensity I of outgoing light emitted to the light receiver R side _l Intensity I relative to the incident light _O Ratio ((I) _l /I _O ) X 100) was 1.9%.

Further, as a result of evaluating the durability in the same manner as in example 1, as shown in FIG. 9, the quartz glass substrate with the ultraviolet absorbing film was subjected to an incident angle of 90℃and 2000mW/cm from the frosted surface side provided with the ultraviolet absorbing film C ² The ultraviolet absorbing film C was not cracked or peeled off after 5000 hours of incidence of the intensity, and the transmittance was not changed before and after ultraviolet irradiation.

Example 3

In a glass vessel, 2-methoxyethanol (formula: CH) ₃ OCHCH ₂ OH) 85.1g polyvinylpyrrolidone K-90.1 g was slowly addedStirring was carried out for 2 hours to dissolve polyvinylpyrrolidone in 2-methoxyethanol. To this solution was added manganese (II) nitrate hexahydrate (formula: mn (NO) ₃ ) ₂ 6H ₂ O) 10.6g, and further stirred for 2 hours, thereby preparing a coating liquid for forming an absorption film which exhibits an extremely pale brown uniform color (manganese oxide system (Mn) _x O _y System) uv-absorbing coating) 100g.

The coating liquid was heat-treated to produce Mn in the whole of manganese (II) nitrate ₂ O ₃ The solid content in the obtained coating liquid for forming an absorption film is converted into Mn ₂ O ₃ The content was 2.9 mass%.

The coating liquid for forming an absorption film was applied to both sides of a glass sheet substrate (S1127, manufactured by Song Nitro Co., ltd., length 76 mm. Times. Width 26 mm. Times. Thickness 1.0 to 1.2 mm) by dipping at a lifting speed of 20 cm/min. The resulting film was a colorless transparent and uniform film.

The glass sheet substrate with the thin film was dried at 70℃under the same conditions as in example 1, and then placed in a heat treatment furnace, and the temperature was raised from room temperature to 500℃at 200℃per hour in an atmosphere, and the temperature was kept at 500℃for 1 hour, whereby a manganese oxide system (Mn) having a film thickness of 1.2 μm was formed on the glass sheet substrate _x O _y Is a UV absorbing film).

By the above heat treatment, the film changed from colorless transparent to dark brown, and the obtained ultraviolet absorbing film was uniform, and no occurrence of cracks and peeling was confirmed.

The transmittance curves of the obtained substrate with and without the ultraviolet absorbing film are shown in fig. 11.

FIG. 11 is a graph showing the transmittance of a substrate alone (without an ultraviolet absorbing film), and the solid line shows the transmittance with Mn _x O _y The transmittance curve of the substrate having the ultraviolet absorbing film shows that the transmittance of the solid line (having the ultraviolet absorbing film) is highly suppressed in the entire ultraviolet region as compared with the broken line (the substrate alone) because the absorption is generated by the manganese oxide constituting the ultraviolet absorbing film in the ultraviolet region of 250 to 420nm (note that in fig. 11,with Mn _x O _y Since the transmittance of the substrate based on the ultraviolet absorbing film was 0% in all the measurement wavelength regions, the horizontal axis and the Mn-containing film of fig. 11 were taken as the horizontal axis _x O _y The transmittance curve of the substrate of the ultraviolet absorbing film is superimposed).

As a result of evaluating the ultraviolet absorption effect in the same manner as in example 1 using the above-mentioned coating liquid for forming an absorption film, when using the quartz glass substrate G on which the ultraviolet absorption film C was formed, the intensity (I _l ) Is 0.15mW/cm ² Intensity I of outgoing light emitted to the light receiver R side _l Intensity I relative to the incident light _O Ratio ((I) _l /I _O ) X 100) was 1.5%.

Example 4

In tetraethoxysilane (illustrative: si (C) ₂ H ₅ O) ₄ ) A mixed solution of 25.2g and 20.2g of isopropyl alcohol and 17.1g of a 0.7 mass% aqueous hydrochloric acid solution and 20.2g of isopropyl alcohol were slowly added thereto, stirred for 2 hours, and then 17.3g of manganese (II) nitrate hexahydrate was added thereto, and further stirred for 2 hours, thereby preparing a colorless transparent and uniform coating solution for forming an absorption film (manganese oxide-SiO ₂ Series (Mn) _x O _y -SiO ₂ System) UV-absorbing coating) 100g.

The coating liquid was heat-treated to produce Cr in the whole of manganese (II) nitrate ₂ O ₃ SiO is formed by tetraethoxysilane ₂ The solid content in the obtained coating liquid for forming an absorption film contained 20 mol% of Mn ₂ O ₃ 80 mol% of SiO ₂ The solid content (all oxides were formed by the heat treatment) in the coating liquid was converted to 20Mn ₂ O ₃ ·80SiO ₂ The content was 12.0 mass%.

The coating liquid for forming an absorption film was applied to both sides of a glass sheet substrate (S1127, manufactured by Song Nitro Co., ltd., length 76 mm. Times. Width 26 mm. Times. Thickness 1.0 to 1.2 mm) by dipping at a lifting speed of 30 cm/min. The resulting film was colorless, transparent and uniform.

The glass sheet substrate with the thin film was dried at 70℃under the same conditions as in example 1, and then placed in a heat treatment furnace, and heated from room temperature to 500℃at 200℃per hour in an atmosphere, and kept at 500℃for 1 hour, to form manganese oxide-SiO on the glass sheet substrate ₂ Series (Mn) _x O _y -SiO ₂ Is a UV absorbing film). The obtained manganese oxide-SiO ₂ Series (Mn) _x O _y -SiO ₂ The film thickness of the ultraviolet absorbing film is less than 1 μm.

By the above heat treatment, the film turned from colorless transparent to brown, and the obtained ultraviolet absorbing film was uniform, and no occurrence of cracks and peeling was confirmed.

The transmittance curves of the obtained substrate with and without the ultraviolet absorbing film are shown in fig. 12.

FIG. 12 is a graph showing the transmittance of a substrate alone (without an ultraviolet absorbing film), and the solid line shows the transmittance with Mn _x O _y -SiO ₂ The transmittance curve of the substrate having the ultraviolet absorbing film shows that the transmittance of the solid line (having the ultraviolet absorbing film) is highly suppressed in the entire ultraviolet region as compared with the broken line (the substrate alone) because the absorption is generated by the manganese oxide constituting the ultraviolet absorbing film in the ultraviolet region of 250 to 420nm

As a result of evaluating the ultraviolet absorption effect in the same manner as in example 1 using the above-mentioned coating liquid for forming an absorption film, when using the quartz glass substrate G on which the ultraviolet absorption film C was formed, the intensity (I _l ) Is 0.21mW/cm ² Intensity I of outgoing light emitted to the light receiver R side _l Intensity I relative to the incident light _O Ratio ((I) _l /I _O ) X 100) was 2.1%.

Comparative example 1

The ultraviolet absorption effect was evaluated in the same manner as in example 1 by using a commercially available anti-reflection coating (GT-7 II manufactured by CANON CHEMICALS Co.) instead of the coating liquid for forming an absorption film, and as a result, the intensity (I _l ) Is 0.19mW/cm ² Intensity I of outgoing light emitted to the light receiver R side _l Intensity I relative to the incident light _O Ratio ((I) _l /I _O ) X 100) was 1.9%.

On the other hand, as a result of evaluating the durability in the same manner as in example 1, the color became lighter (black to gray) with the lapse of the ultraviolet light irradiation time, and peeling occurred at an irradiation time of 1000 hours.

The results of examples 1 to 4 and comparative example 1 are summarized in Table 1.

TABLE 1

As is clear from table 1, since the ultraviolet absorbing films obtained in examples 1 to 4 contain the oxide of the specific transition metal, in the device capable of outputting ultraviolet light having a large light energy with high intensity, even when used for absorbing ultraviolet light, an ultraviolet absorbing film capable of highly suppressing the generation of stray light in a thin film state and exhibiting excellent durability can be formed.

In contrast, as is clear from table 1, the coating film obtained from the commercially available anti-reflection coating material used in comparative example 1 contains an organic resin and does not contain a specific transition metal oxide, and therefore, discoloration and peeling occur in the durability test by irradiation with ultraviolet light.

Example 5

In example 3, manganese (II) nitrate hexahydrate (formula: mn (NO) ₃ ) ₂ 6H ₂ A light brown uniform coating liquid for forming an absorbing film (manganese oxide system (Mn) was prepared in the same manner as in example 3 except that the amount of O) added was changed from 10.6g to 12.7g _x O _y System) UV-absorbing coating) 100g.

The coating liquid was heat-treated to produce Mn in the whole of manganese (II) nitrate ₂ O ₃ The solid content in the obtained coating liquid for forming an absorption film is converted into Mn ₂ O ₃ 3.5 mass%.

The coating liquid for forming an absorption film was applied to both sides of a glass sheet substrate (S1127, manufactured by Song Nitro Co., ltd., length 76 mm. Times. Width 26 mm. Times. Thickness 1.0 to 1.2 mm) by dipping at a lifting speed of 5 cm/min in the same manner as in example 3. The resulting film was colorless, transparent and uniform.

The glass sheet substrate with the thin film was dried at 130℃for 1 hour to change the state of the thin film from colorless transparent to light brown transparent and uniform, and then placed in a heat treatment furnace, and heated from room temperature to 450℃at 200℃per hour in an atmosphere, and kept at 450℃for 1 hour, whereby a manganese oxide system (Mn) having a film thickness of 1.0 μm was formed on the glass sheet substrate _x O _y Is a UV absorbing film).

Example 6

In the same manner as in example 5, a catalyst was added in terms of Mn ₂ O ₃ Manganese (II) nitrate hexahydrate (formula: mn (NO) ₃ ) ₂ 6H ₂ O), a coating liquid for forming an absorption film was prepared uniformly exhibiting an extremely pale brown color (manganese oxide system (Mn) _x O _y Is based on) 100g of an ultraviolet absorbing coating material, and then adding to the coating liquid0.50g of methylene blue trihydrate as a colorant was added thereto and stirred at room temperature for 1 hour, thereby preparing a colorant-containing coating liquid for forming an absorption film. The obtained coating liquid was a uniform liquid exhibiting dark navy.

The coating liquid for forming an absorption film was applied to both sides of a glass sheet substrate (S1127, manufactured by Song Nitro Co., ltd., length 76 mm. Times. Width 26 mm. Times. Thickness 1.0 to 1.2 mm) by dipping at a lifting speed of 5 cm/min in the same manner as in example 5. The resulting film was a blue transparent and uniform film.

The glass sheet substrate with the thin film was dried at 130℃for 1 hour in the same manner as in example 5, the state of the thin film was changed from blue transparent to blue transparent and uniform with light brown, and then the glass sheet substrate was put into a heat treatment furnace, and the temperature was raised from room temperature to 450℃at 200℃per hour in an atmosphere and kept at 450℃for 1 hour, whereby a manganese oxide system (Mn) having a film thickness of 1.0 μm was formed on the glass sheet substrate _x O _y Is a UV absorbing film).

By the above heat treatment, the film changed from blue transparent to dark brown immediately after coating, and the obtained ultraviolet absorbing film was uniform, and no occurrence of cracks and peeling was confirmed.

When the coating liquid for forming an absorbing film containing a colorant is applied to the edge of a lens, a blue transparent coating film can be easily formed, and the presence or absence of the coating film can be easily confirmed by the naked eye. In addition, it can be easily confirmed whether or not the coating liquid is slightly adhered to the incident surface and the exit surface of the lens, the adhesion of the coating liquid is limited.

Fig. 13 is a graph showing two transmittance curves, namely: the transmittance curve (dotted line) of the coating film immediately after the coating liquid for forming an absorption film obtained in example 5 was applied to a glass sheet and dried at 130 ℃ for 1 hour, and the transmittance curve (solid line) of the coating film immediately after the coating liquid for forming an absorption film containing a colorant obtained in example 6 was applied to a glass sheet and dried at 130 ℃ for 1 hour.

As is clear from fig. 13, the coating liquid obtained in example 6 has a colorant, and the transmittance in the visible light range is reduced, thereby improving the visibility.

Fig. 14 is a graph showing two transmittance curves, namely: the coating liquid for forming an absorption film obtained in example 5 was applied to a glass sheet and dried at 130 ℃ for 1 hour, and then heat-treated to obtain a transmittance curve (dotted line) of the coating film, and the coating liquid for forming an absorption film containing a colorant obtained in example 6 was applied to a glass sheet and dried at 130 ℃ for 1 hour, and then heat-treated to obtain a transmittance curve (solid line) of the coating film.

As shown in fig. 14, it is clear that the coating liquid for forming an absorbing film containing no colorant obtained in example 5 and the coating liquid for forming an absorbing film containing a colorant obtained in example 6 were applied to a glass sheet, dried, and then heat-treated to obtain any dark brown coating film, and therefore, even though the coating liquid for forming an absorbing film contained a colorant, the transmittance of the coating film obtained after heat treatment was not affected.

Fig. 15 is a graph showing a transmittance curve (broken line) when the coating liquid for forming an absorbing film obtained in example 5 was added to an acrylic resin cell having an optical path length of 10mm and a transmittance curve (solid line) when the coating liquid for forming an absorbing film obtained in example 6 was added to an acrylic resin cell having an optical path length of 10mm (in fig. 15, the transmittance of the coating liquid for forming an absorbing film obtained in example 6 was substantially 0% in the entire visible light range, and the transmittance curve was substantially coincident with the horizontal axis).

As is clear from fig. 15, since the thickness of the measurement object is larger than that of the coating film measured in fig. 13, in example 6, the effect of the coating liquid having a transmittance reduction (visibility improvement) in the visible light region due to the colorant can be more clearly recognized.

Example 7

As shown in fig. 5, 4 UV-LED chips (emission wavelength: 395 nm) D of 1mm in length and 1mm in width are adjacently arranged as light sources on a substrate B, and a first lens Ll, a second lens L2, and a third lens L3 are provided in this order on the UV-LED side (light emission side) light irradiation side, forming an optical unit.

As shown in fig. 5, the first lens Ll, the second lens L2 and the third lens K3 were each coated with the ultraviolet absorbing paint prepared in example 3 over the entire edges, then dried at 100 ℃ for 1 hour, then put into a heat treatment furnace, heated from room temperature to 450 ℃ at 200 ℃/hour in an atmosphere, and kept at 450 ℃ for 1 hour, thereby forming a manganese oxide-based ultraviolet absorbing film having a thickness of 1.5 μm on the edges.

Next, as shown in fig. 6, a light irradiation device (peripheral exposure light source device) was fabricated by arranging 25 of the above-mentioned optical units in a plane of 5×5.

As schematically shown in fig. 16 (a), the peripheral portion of the semiconductor silicon wafer 1 obtained by applying the photoresist film 1a having a thickness of 3 μm over the entire main surface was exposed (peripheral exposure) using the above-mentioned light irradiation apparatus under the condition of an accumulated light amount of 25mJ, and then the unnecessary resist film in the peripheral portion of the wafer was removed using a chemical agent.

In the peripheral exposure, it is desirable that the resist film 1a is removed as widely as possible from the edge (end portion) of the wafer 1 shown in fig. 16 (a), and that the usable area of the resist film 1a is enlarged as much as possible, so that it is desirable that the resist film 1a is removed as much as possible in a right angle shape so that the edge portion E becomes sharp (steep rise) in the vicinity of the outer periphery of the silicon wafer 1, as schematically shown in fig. 16 (b).

In contrast, as schematically shown in fig. 16 (c), the silicon wafer 1 obtained by the peripheral exposure treatment was removed so that the end of the photoresist film became sharp (so as to be steeply elevated), and the collapse width d of the edge portion E (the lateral width of the portion formed by the inclined portion) was 31 μm (about 10 times the film thickness).

The above-mentioned light irradiation apparatus was continuously used for 5000 hours, and the photoresist film in the peripheral portion of the semiconductor silicon wafer was exposed, and the end portion of the photoresist film was removed (steeply rising) so as to sharpen the end portion of the obtained silicon wafer, and the collapse width d was 30 μm, which was equal to that before the continuous use.

Comparative example 2

In example 7, an optical unit was formed in the same manner as in example 7 except that the first lens, the second lens, and the third lens forming the optical unit were each lenses having no ultraviolet absorbing film, and then 25 of the optical units were arranged in a plane of 5×5 as in example 7, thereby producing a light irradiation device (peripheral exposure light source device).

The peripheral portion of a semiconductor silicon wafer obtained by applying a photoresist film having a thickness of 3 μm to the entire main surface was exposed (peripheral exposure) using the obtained light irradiation apparatus in the same manner as in example 5 under the condition that the cumulative light amount was 25mJ, and then the unnecessary resist film in the peripheral portion of the wafer was removed using a chemical agent.

As schematically shown in fig. 16 (d), the silicon wafer obtained by the above-described process is formed by removing the edge portion E of the photoresist film 1a with a gently inclined sagging, and the sagging width d is 120 μm (40 times the film thickness).

Since a silicon wafer is processed while holding its peripheral portion, if a resist film is also applied to the peripheral portion of the wafer, the resist film is peeled off during processing of the wafer to generate particles, which results in a reduction in yield, and therefore, it is desired to remove an unnecessary resist film in the peripheral portion of the wafer in advance.

Therefore, in the case of removing the resist film in the peripheral portion of the silicon wafer, it is desirable to remove the resist film as widely as possible from the edge (end portion) of the silicon wafer from the viewpoint of suppressing the occurrence of the particles, but it is desirable to enlarge the area where the resist film can be used as much as possible, so that it is desirable to remove the resist film so that the edge portion becomes sharp (so as to be steeply elevated) in the peripheral vicinity of the silicon wafer.

However, conventionally, when a resist film is removed by exposure using a light irradiation device, stray light generated by an optical element such as a lens and an optical element is mixed into the original exposure light, and a gently inclined collapse is likely to occur in an edge portion of the resist film.

It is clear that the light irradiation device obtained in example 7 includes the optical element or the optical unit having the ultraviolet absorbing film of the present invention, and therefore can not only highly suppress the generation of stray light, but also exhibit excellent durability.

On the other hand, it was found that the light irradiation device obtained in comparative example 2 did not include the optical element or the optical unit having the ultraviolet absorbing film of the present invention, and therefore, the generation of light stray light could not be suppressed, and sagging occurred at the edge portion of the resist film.

Industrial applicability

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

Claims

1. An optical element for an ultraviolet irradiation device, comprising an 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 transition metal is 20 to 100 mass%.

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

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

4. An optical element for an ultraviolet irradiation device, comprising a light-absorbing film comprising a laminate of an ultraviolet-absorbing film and an absorbing film that absorbs at least visible light or infrared light, wherein the ultraviolet-absorbing film contains an oxide of one or more transition metals selected from Cr, mn and Ni, and the content of the oxide of the transition metal is 20 to 100 mass%.

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

6. An ultraviolet light irradiation apparatus having the optical unit for an ultraviolet light irradiation apparatus according to claim 5.