Light-emitting device and curable composition

Abstract

A light-emitting device (1) has a light-emitting element (2), an optical glass member (3), and an adhesive layer (5) that bonds the light-emitting element (2) and the optical glass member (3) to each other, wherein: the adhesive layer (5) contains a silicone resin that has an organosiloxy unit (T unit) which is represented by RSiO3 / 2 wherein R represents an organic group, and an organosiloxy unit (Q unit) which is represented by SiO4 / 2; and in the infrared absorption spectrum of the adhesive layer (5), the ratio (A1055 / A1270) of the maximum value A1055 of the absorbance at 1,055 cm-1 ± 10 cm-1 to the maximum value A1270 of the absorbance at 1,270 cm-1 ± 5 cm-1 is 1.55 to 2.5 inclusive.

Description

Light-emitting device and curable composition

[0001] The present disclosure relates to a light emitting device and a curable composition.

[0002] As a light-emitting device that emits ultraviolet light, a light-emitting device including a light-emitting element, a lens, and an adhesive layer that bonds the light-emitting element and the lens has been developed. From the viewpoint of improving output such as light extraction efficiency, an adhesive layer that has sufficient adhesiveness, can transmit ultraviolet light, and is light-resistant to ultraviolet light has been studied.

[0003] To date, in order to provide a cured product with excellent crack resistance, a cured product of a silanol composition containing a cyclic silanol having a cyclic structure formed by a siloxane bond and a dehydration condensate thereof has been reported, which has a peak at 960 cm in the IR spectrum. －１ ~1220cm －１ The area of ​​the peak due to Si-O-Si stretching observed at 2600 cm －１ ~3800cm －１ A cured product has been reported in which the area ratio of the peak due to SiO—H stretching observed in the SiO—H stretching / Si—O—Si stretching area ratio is 0.01 or more and 1.0 or less (see, for example, Patent Document 1).

[0004] International Publication No. 2020 / 171136

[0005] An object of one embodiment of the present disclosure is to provide a light-emitting device having an adhesive layer that has excellent adhesiveness and light resistance and that has reduced air bubbles.

[0006] A light emitting device according to one aspect of the present disclosure includes an optical glass member, an adhesive layer, and a light emitting element, wherein the adhesive layer is made of RSiO ３／２ wherein R represents an organic group; and an organosiloxy unit (T unit) represented by the formula: ４／２ and a silicone resin having an organosiloxy unit (Q unit) represented by the following formula: －１ ±5cm －１ Maximum absorbance A １２７０ 1055 cm －１ ±10cm －１Maximum absorbance A １０５５ The ratio (A １０５５ / A １２７０ ) is 1.55 or more and 2.5 or less.

[0007] According to one aspect of the present disclosure, a light-emitting device can be provided that has an adhesive layer that has excellent adhesiveness and light resistance and reduced air bubbles.

[0008] FIG. 1 is a cross-sectional view showing a light emitting device according to an embodiment.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding components are denoted by the same reference numerals, and their description may be omitted. In the specification, the symbol "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits.

[0010] (Light Emitting Device) The light emitting device of this embodiment includes a light emitting element, an optical glass member, the adhesive layer that bonds the light emitting element and the optical glass member, and may further include other members as necessary.

[0011] The adhesive layer is RSiO ３／２ (wherein R represents an organic group), and an organosiloxy unit (T unit) represented by SiO ４／２ and a silicone resin having organosiloxy units (Q units) represented by the following formula:

[0012] In the infrared absorption spectrum of the adhesive layer, －１ ±5cm －１ Maximum absorbance A １２７０ 1055 cm －１ ±10cm －１ Maximum absorbance A １０５５ The ratio (A １０５５ / A １２７０ ) is 1.55 or more and 2.5 or less.

[0013] A light emitting device 1 according to one embodiment will be described with reference to Fig. 1. The light emitting device 1 includes a light emitting element 2, a lens 3, and an adhesive layer 5 that bonds the light emitting element 2 to the lens 3. The lens 3 is an example of an optical glass member.

[0014] <Light-Emitting Element> The light-emitting element 2 is not particularly limited as long as it emits light including ultraviolet light and can be appropriately selected depending on the purpose. However, an element that emits light with ultraviolet light as its peak emission wavelength is preferred. A portion of the light-emitting element 2, the adhesive layer 5, and the lens 3 transmit light in this order. The ultraviolet light preferably has a wavelength of 200 nm to 320 nm, more preferably UVC (e.g., 200 nm to 280 nm) or a wavelength of 240 nm to 290 nm, and may be, for example, 265 nm or 280 nm. The "peak emission wavelength" refers to the wavelength with the highest output value in the spectral distribution of the emitted light. The radiant flux of the light-emitting element 2 is, for example, greater than 20 mW, preferably 35 mW or more, and more preferably 40 mW or more. From the viewpoint of the heat dissipation properties of the light-emitting element 2, the radiant flux of the light-emitting element 2 may be 120 mW or less. The radiant flux is the radiant energy emitted per unit time. The radiant flux is measured in accordance with CIE 127:2007.

[0015] The light-emitting element 2 has, for example, a substrate 22 and a semiconductor layer 23. The light-emitting element 2 has, for example, a flip-chip structure. When the light-emitting element 2 has a flip-chip structure, light generated in the semiconductor layer 23 is emitted through the substrate 22. The substrate 22 is a transparent substrate that transmits light. The surface of the substrate 22 facing the lens 3 is the light-emitting surface 21 of the light-emitting element 2.

[0016] The substrate 22 is made of, for example, a sapphire substrate or an aluminum nitride substrate. An aluminum nitride substrate is a substrate made of a single crystal of aluminum nitride. A sapphire substrate or an aluminum nitride substrate is a transparent substrate that transmits ultraviolet light. The thickness t of the substrate 22 is, for example, 0.05 mm to 2 mm.

[0017] The semiconductor layer 23 is provided on the opposite side of the substrate 22 from the lens 3. The semiconductor layer 23 emits light when a voltage is applied to it. An electrode for applying a voltage to the semiconductor layer 23 is formed on the opposite side of the substrate 22 from the semiconductor layer 23 so as not to block the light traveling from the semiconductor layer 23 to the substrate 22, although this is not shown. This makes it possible to prevent a decrease in light extraction efficiency.

[0018] The light-emitting element 2 may be bonded to a mounting substrate via solder bumps. The mounting substrate is, for example, a ceramic substrate made of sintered aluminum nitride, sintered aluminum oxide, or LTCC (Low Temperature Co-fired Ceramics) on which electrodes are formed.

[0019] The surface roughness Ra of the light emitting surface 21 of the light emitting element 2 is, for example, 0.01 nm to 5 nm. When a fine uneven structure is formed on the light emitting surface 21 to improve the extraction efficiency of ultraviolet light, the surface roughness Ra of the light emitting surface 21 is 5 nm to 50 nm. The surface roughness Ra of the opposing surface 31 of the lens 3 is, for example, 0.01 nm to 5 nm. The surface roughness Ra is the arithmetic mean roughness as defined in JIS B0601:2001.

[0020] <Optical Glass Member> The lens 3 suppresses total reflection of light and improves light extraction efficiency. The lens 3 has an opposing surface 31 facing the light emission surface 21 of the light-emitting element 2, and a convex curved surface 32 facing away from the opposing surface 31. The ultraviolet light emitted by the light-emitting element 2 is incident on the opposing surface 31 and exits from the convex curved surface 32. The convex curved surface 32 is a dome-shaped curved surface whose center protrudes further than the periphery.

[0021] The lens 3 may be a spherical lens or an aspherical lens. Although not shown, the lens 3 may have a flange that protrudes radially outward from the periphery of the convex curved surface 32.

[0022] Although not shown, the convex curved surface 32 of the lens 3 may have irregularities that prevent reflection of light generated by the light emitting element 2. The irregularities of the convex curved surface 32 have, for example, a moth-eye structure, and prevent light traveling from the inside of the lens 3 to the outside from being reflected back into the lens 3, thereby improving the light extraction efficiency.

[0023] Although not shown, the light emitting device 1 may be provided with an anti-reflection coating on the convex curved surface 32 of the lens 3. The anti-reflection coating prevents light traveling from the inside of the lens 3 to the outside from being reflected back into the lens 3, thereby improving the light extraction efficiency. A general anti-reflection coating is used.

[0024] Although not shown, the convex curved surface 32 of the lens 3 may have irregularities that scatter the ultraviolet light generated by the light emitting element 2. The irregularities of the convex curved surface 32 scatter the ultraviolet light emitted from the convex curved surface 32, thereby emitting the ultraviolet light over a wider range.

[0025] The material of the lens 3 is, for example, oxide glass. Oxide glass can be processed by various processing methods such as thermoforming or grinding and polishing, and a processing method suitable for the shape of the lens 3 can be selected. Examples of oxide glass include soda-lime glass, alkali-free glass, chemically strengthened glass, and lanthanum borate glass. In order to reduce the loss of ultraviolet light caused by the lens 3, a material with low ultraviolet light absorption is suitable as the material of the lens 3, and the material of the lens 3 is preferably quartz, quartz glass, or sapphire.

[0026] <Adhesive Layer> The adhesive layer 5 is made of RSiO ３／２ (wherein R represents an organic group), and an organosiloxy unit (T unit) represented by SiO ４／２ and a silicone resin having organosiloxy units (Q units) represented by the following formula:

[0027] In the infrared absorption spectrum of the adhesive layer 5, －１ ±5cm －１ Maximum absorbance A １２７０ 1055 cm －１ ±10cm －１ Maximum absorbance A １０５５ The ratio (A １０５５ / A １２７０ ) is 1.55 or more and 2.5 or less.

[0028] The adhesive layer 5 is preferably made of a silicone resin.

[0029] The adhesive layer 5 can be suitably prepared by curing the curable composition of the present embodiment, which will be described later.

[0030] Silicone resins have the advantages of being transparent and having excellent light and ultraviolet transmittance. However, the shorter the peak wavelength of ultraviolet light emitted by the light-emitting element 2, the more the conventional organic material (e.g., silicone resins having organic groups) forming the adhesive layer 5 deteriorates. Furthermore, the stronger the radiant flux of the light-emitting element 2 is in order to improve output, the more likely the adhesive layer 5 is to deteriorate, resulting in cracks. Deterioration of the adhesive layer 5 reduces light transmittance and light extraction efficiency. Meanwhile, conventional adhesives with excellent light resistance have a problem in that the adhesive strength between the light-emitting element and the optical glass member is weak, resulting in the optical glass member easily falling off. Therefore, it is difficult to achieve both light resistance and adhesiveness. Furthermore, when the silicone resin contains a large amount of low-molecular-weight siloxane components having Q units, bubbles are generated due to volatile components and decomposition products as the silicone resin hardens. Light scattering by the bubbles reduces the light extraction efficiency.

[0031] The present inventors have discovered that the adhesive layer contains a silicone resin having T units and Q units, and that the ratio of specific absorbances (A １０５５ / A １２７０ ) can provide a light-emitting element having an adhesive layer with excellent adhesiveness and light resistance and reduced bubbles, and a curable composition. As a result, the light-emitting element 2 emits ultraviolet light with a peak wavelength of 220 nm to 320 nm, and the radiant flux of the light-emitting element 2 is 20 mW / cm ２ Even if the thickness exceeds 100 nm, an adhesive layer can be formed that has excellent adhesion, light resistance, and reduced air bubbles. LEDs such as UVC-LEDs have lower output than high-output mercury lamps, which has hindered their widespread use in terms of cost-effectiveness. However, even when an LED is used as the light-emitting element 2, it is possible to improve the light extraction efficiency and achieve excellent adhesion, light resistance, and reduced air bubbles, which is also advantageous in terms of manufacturing costs.

[0032] -Silicone Resin- Silicone resins have organosiloxy units. Organosiloxy units include monofunctional organosiloxy units called M units, difunctional organosiloxy units called D units, trifunctional organosiloxy units called T units, and tetrafunctional organosiloxy units called Q units. Q units are units that do not have an organic group bonded to a silicon atom (an organic group having a carbon atom bonded to a silicon atom), but are considered organosiloxy units (silicon-containing units) in this specification. Monomers that form M units, D units, T units, and Q units are also referred to as M monomers, D monomers, T monomers, and Q monomers, respectively.

[0033] In the organosiloxy unit, the siloxane bond is a bond in which two silicon atoms are bonded via one oxygen atom, so the number of oxygen atoms per silicon atom in the siloxane bond is considered to be 1 / 2, and in the formula, O １／２ More specifically, for example, in one D unit, one silicon atom is bonded to two oxygen atoms, and each oxygen atom is bonded to a silicon atom of another unit, so the formula is -O １／２ - (R) ２ Si—O １／２ - (R represents a hydrogen atom or an organic group). １／２ Since there are two units, the D unit is (R) ２ SiO ２／２ (In other words, (R) ２ It is usually expressed as SiO.

[0034] In the following description, an oxygen atom O bonded to another silicon atom ＊ is an oxygen atom bonding two silicon atoms, and means an oxygen atom in a bond represented by Si—O—Si. ＊ is present between the silicon atoms of two organosiloxy units.

[0035] T units are RSiO ３／２(R represents a hydrogen atom or an organic group). That is, the T unit has one silicon atom, one hydrogen atom or an organic group bonded to the silicon atom, and an oxygen atom O bonded to another silicon atom. ＊ It is a unit that has three of these.

[0036] Q units are SiO ２ That is, the Q unit has one silicon atom and an oxygen atom O bonded to another silicon atom. ＊ It is a unit that has four of these.

[0037] M unit is (R) ３ SiO １／２ Here, R represents a hydrogen atom or an organic group. The number (here, 3) after (R) means that three hydrogen atoms or organic groups are bonded to the silicon atom. In other words, the M unit is a unit consisting of one silicon atom, three hydrogen atoms or organic groups, and one oxygen atom O. ＊ More specifically, the M unit has three hydrogen atoms or organic groups bonded to one silicon atom, and one oxygen atom O bonded to one silicon atom. ＊ It has.

[0038] D unit means (R) ２ SiO ２／２ (R represents a hydrogen atom or an organic group). That is, the D unit has one silicon atom, two hydrogen atoms or organic groups bonded to the silicon atom, and an oxygen atom O bonded to another silicon atom. ＊ It is a unit that has two of these.

[0039] Examples of the organic group include monovalent hydrocarbon groups such as alkyl groups, aryl groups, and aralkyl groups; halogen-substituted monovalent hydrocarbon groups, etc. Among these, unsubstituted or halogen-substituted monovalent hydrocarbon groups having 1 to 12 carbon atoms are preferred, and unsubstituted or halogen-substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms are more preferred.

[0040] Examples of alkyl groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclohexyl, and heptyl groups. Examples of aryl groups include phenyl, tolyl, xylyl, and naphthyl groups. Examples of aralkyl groups include benzyl and phenethyl groups. Examples of halogen-substituted monovalent hydrocarbon groups include halogenated alkyl groups, halogenated aryl groups, and halogenated aralkyl groups. Examples of halogenated alkyl groups include chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl groups.

[0041] In this specification, the total organosiloxy units constituting the silicone resin means the sum of M units, D units, T units, and Q units. The proportions (mol %) of the numbers of M units, D units, T units, and Q units are as follows: ２９ It can be calculated from the peak area ratio value by Si-NMR.

[0042] The organic group R in the T unit is not particularly limited and can be appropriately selected depending on the purpose, but is preferably a methyl group.

[0043] The silicone resin has T units and Q units, and the ratio of absorbance (A １０５５ / A １２７０ ) is satisfied, it can be appropriately selected depending on the purpose without any particular limitation, and may contain M units and D units, but is preferably composed of T units and Q units.

[0044] Silicone resins are usually obtained by curing (crosslinking) curable silicones. In other words, silicone resins are the cured products of curable silicones. Curable silicones are classified into condensation reaction type silicones, addition reaction type silicones, ultraviolet curable silicones, and electron beam curable silicones depending on their curing mechanism, and any of them can be used.

[0045] Metal Element: The adhesive layer 5 preferably further contains at least one metal element selected from 3d transition metals, 4d transition metals, lanthanoid metals, bismuth, aluminum, tin, and zinc. This suppresses the generation of bubbles in the adhesive layer 5 during high-temperature heat treatment (e.g., 500°C to 600°C) in an inert gas atmosphere. The reason (mechanism) for obtaining this effect is not clear, but it is thought that the generation of volatile components is reduced by the metal element crosslinking portions that decompose as the polymerization reaction progresses in the adhesive layer 5.

[0046] Among the metal elements, 3d transition metals such as Ti, Mn, Fe, Co, Ni, and Cu, and zinc (Zn) are preferred in terms of further reducing bubbles. These may be used alone or in combination of two or more. The form of the metal element may be any of metal, ion, compound, and complex.

[0047] In terms of reducing bubbles, the content of the metal element is preferably 0.02 mass% to 1.5 mass%, more preferably 0.03 mass% to 1.0 mass%, even more preferably 0.04 mass% to 0.3 mass%, and particularly preferably 0.06 mass% to 0.3 mass%, relative to the total amount of the adhesive layer 5.

[0048] The method for measuring the metal elements in the adhesive layer 5 is not particularly limited, and known methods can be used, such as inductively coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), etc. Examples of devices that can be used in the above method include an inductively coupled plasma atomic emission spectrometry analyzer PS3520UVDDII (Hitachi High-Technologies Corporation) and an inductively coupled plasma (triple quadrupole) mass spectrometer Agilent 8800 (Agilent Technologies).

[0049] [Configuration of Adhesive Layer] The adhesive layer 5 bonds the light emitting surface 21 of the light emitting element 2 and the opposing surface 31 of the lens 3 so that they face each other. It is preferable that the light emitting surface 21 of the light emitting element 2 and the opposing surface 31 of the lens 3 each have a flat surface at least in the area where they overlap. The opposing surface 31 of the lens 3 is larger than the light emitting surface 21 of the light emitting element 2, and may have a curved surface in the area extending beyond the light emitting surface 21.

[0050] The interface between the adhesive layer 5 and the light-emitting element 2 is called the first interface. In this embodiment, the first interface is the entire light-emitting surface 21, but it may be a part of the light-emitting surface 21. In addition, the interface between the adhesive layer 5 and the lens 3 is called the second interface. In this embodiment, the second interface is the entire opposing surface 31, but it may be a part of the opposing surface 31.

[0051] The average thickness of the adhesive layer 5 is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5 μm or less, more preferably 4 μm or less in terms of reducing bubbles, and is preferably 0.5 μm or more, more preferably 1 μm or more in terms of adhesiveness.

[0052] Maximum thickness T of adhesive layer Ｍ and minimum thickness T ｍ The difference between (T Ｍ -T ｍ ) is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.5 μm or less, more preferably 0.4 μm or less.

[0053] The thickness of the adhesive layer 5 can be determined by scratching any five points on the bonding portion of the adhesive layer 5 remaining on the bottom surface of the light emitting element 2 and / or lens 3 after removing the glass lens from the light emitting element, and measuring the step portion of the scratch using a non-contact surface texture measuring device (for example, PF-60, manufactured by Mitaka Kohki Co., Ltd.), thereby determining the height of the step as the thickness of the adhesive layer. The average thickness of the adhesive layer 5 can be determined by measuring the thickness of the adhesive layer at any five or more points and calculating the average value.

[0054] Maximum thickness T of adhesive layer Ｍ and minimum thickness T ｍ The difference between (T Ｍ -T ｍ ) is the maximum thickness T Ｍ and minimum thickness T ｍ and the maximum thickness T Ｍ and minimum thickness T ｍ The difference between (T Ｍ -T ｍ ) can be obtained by calculating

[0055] The surface roughness of the adhesive surface of the adhesive layer 5 that is bonded to the light-emitting element 2 is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.01 nm or more and 50 nm or less. The surface roughness can be measured by a measurement method using, for example, a non-contact surface / layer cross-sectional shape measurement system (e.g., Vertscan R3300-lite, manufactured by Ryoka Systems Co., Ltd.), an atomic force microscope (AFM), a laser microscope (e.g., UV-X3000, manufactured by Keyence Corporation), a non-contact surface property measurement device (e.g., PF-60, manufactured by Mitaka Kohki Co., Ltd.), or the like.

[0056] The indentation modulus of the adhesive layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 GPa or more and 10 GPa or less. The indentation modulus can be measured using an ultra-microindentation hardness tester (for example, ENT-NEXUS, manufactured by Elionix Co., Ltd.) by setting the load so that the indentation depth is 1 / 10 or less of the thickness of the adhesive layer.

[0057] [Ratio of absorbance of adhesive layer (A １０５５ / A １２７０ In the infrared absorption spectrum of the adhesive layer 5, －１ ±5cm －１ Maximum absorbance A １２７０ 1055 cm －１ ±10cm －１ Maximum absorbance A １０５５ The ratio (A １０５５ / A １２７０ ) is 1.55 or more and 2.5 or less, preferably 1.6 or more and 2.0 or less, and more preferably 1.65 or more and 1.75 or less.

[0058] Here, when the infrared absorption spectrum of the adhesive layer was measured by the attenuated total reflection method (ATR method) of infrared spectroscopy (FT-IR), －１ ±5cm －１ Maximum absorbance A １２７０ indicates the absorbance due to the Si-C bond contained in the T unit in the silicone resin, and 1055 cm －１ ±10cm －１ Maximum absorbance A １０５５indicates the absorbance derived from the low-molecular-weight siloxane component contained in the Q unit in the silicone resin.

[0059] (Curable Composition) The curable composition of the present embodiment is a curable composition of RSiO ３／２ (wherein R represents an organic group), and a siloxane component having an organosiloxy unit (T unit) represented by the formula: ４／２ and a siloxane component having organosiloxy units (Q units) represented by the formula: and may further contain other components as required.

[0060] The curable composition was dried at 120°C for 30 minutes and then heated at 200°C for 30 minutes to obtain a cured product, which had a peak at 1270cm in the infrared absorption spectrum. －１ ±5cm －１ Maximum absorbance A １２７０ 1055 cm －１ ±10cm －１ Maximum absorbance A １０５５ The ratio (A １０５５ / A １２７０ ) is 1.55 or more and 2.5 or less, preferably 1.6 or more and 2.0 or less, and more preferably 1.65 or more and 1.75 or less.

[0061] In a cured product obtained by curing a curable composition containing a siloxane component having T units, a siloxane component having Q units, and optionally other components, the silicone resin described in the adhesive layer is obtained by condensation of each siloxane component. As the siloxane component having T units, a silicone resin having T units is preferred. As the siloxane component having Q units, a low-molecular-weight siloxane component (also referred to as an oligomer) is preferred, and may be linear or cyclic.

[0062] The silicone resin and metal elements can be selected as appropriate from those described above in connection with the adhesive layer of the light-emitting device of this embodiment. ３／２ In the T unit represented by the formula: (wherein R represents an organic group), R is preferably a methyl group.

[0063] The curable component in the curable composition is RSiO３／２ (wherein R represents an organic group), and a siloxane component having an organosiloxy unit (T unit) represented by the formula: ４／２ and a siloxane component having organosiloxy units (Q units) represented by the following formula: wherein a silicone resin comprising T units and Q units can be formed in the resulting adhesive layer.

[0064] Examples of other components include siloxane components such as a siloxane component having an M unit and a siloxane component having a D unit, metal elements, and additives such as solvents, silane coupling agents, and stabilizers. From the viewpoint of reducing bubbles, the curable composition preferably further contains at least one metal element selected from 3d transition metals, 4d transition metals, lanthanoid metals, bismuth, aluminum, tin, and zinc.

[0065] The form of the curable composition may be a liquid or sol, or may be a film or sheet, but is preferably a film from the viewpoint of handleability. It can be used in a method in which a film-like curable composition (hereinafter sometimes referred to as a curable composition film) formed on a release substrate is transferred to a light-emitting element or an optical glass member such as a lens, and if necessary, after transfer, it is deformed according to the member and then cured.

[0066] In the case of a film-like composition, the average thickness of the film-like curable composition is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5 μm or less, more preferably 4 μm or less in terms of reducing bubbles, and is preferably 0.5 μm or more, more preferably 1 μm or more in terms of adhesiveness.

[0067] The method for forming the film-like curable composition is not particularly limited, and any known method can be appropriately selected depending on the purpose. For example, a method of applying a liquid or sol-like curable composition to a release substrate such as a release film and drying the composition can be used.

[0068] Examples of methods for applying a liquid or sol curable composition include spin coating, spray coating, bar coating, gravure coating, screen printing, inkjet coating, etc. Methods for drying a liquid or sol curable composition may be any methods capable of removing a solvent, if any, and examples thereof include a method of drying at 100°C to 140°C for 10 minutes to 30 minutes.

[0069] [Method for manufacturing light-emitting device] The method for manufacturing a light-emitting device is not particularly limited and any known method can be appropriately selected depending on the purpose. For example, a method can be used in which a curable composition is placed between an optical glass member and a light-emitting element, and the curable composition is heated to harden the composition, thereby bonding the light-emitting element and the optical glass member together.

[0070] The method for disposing the curable composition may be to apply a liquid or sol-like curable composition, or to dispose a film-like curable composition by transfer or the like, and either method can be suitably selected.

[0071] In order to bond the optical glass member and the light-emitting element 2 with sufficient adhesive strength using the adhesive layer 5, it is preferable to thoroughly clean the surfaces of the optical glass member and the light-emitting element 2 to be bonded. The cleaning method is not particularly limited, but cleaning can be performed using, for example, a hydrocarbon solvent such as ethanol or acetone, a fluorine-based solvent such as AS-300 (manufactured by AGC Inc.), or an aqueous cleaner such as an alkaline detergent. Furthermore, adhesive strength can also be improved by subjecting the surfaces to be bonded to a surface activation treatment. For example, UV ozone treatment, atmospheric pressure plasma treatment, excimer UV treatment, corona treatment, etc. can be used.

[0072] The method for bonding the optical glass member and the light-emitting element 2 is not particularly limited and can be selected appropriately depending on the purpose. For example, a method in which the optical glass member and the light-emitting element 2 are bonded together under atmospheric pressure, reduced pressure, or vacuum can be used.

[0073] The method for curing the curable composition is not particularly limited, and heat curing, photocuring, or the like can be appropriately selected depending on the purpose. For example, a method of performing a heat treatment at 180°C to 220°C for 20 to 60 minutes can be mentioned. In order to obtain sufficient adhesive strength, autoclave treatment (heating and pressurizing treatment) or pressurizing treatment may be performed when or after bonding the optical member and the light-emitting element 2. Furthermore, after bonding, the light-emitting element 2 may be made to emit light, and the adhesive layer 5, which is a silicone resin layer, may be subjected to an aging treatment. The heat treatment, autoclave treatment, and aging treatment may be performed in an atmospheric pressure atmosphere or an inert gas atmosphere.

[0074] The experimental data will be explained below. Examples 1 to 10 are working examples, and Examples 11 to 14 are comparative examples.

[0075] Example 1 Preparation of a Siloxane Component Having T Units Triethoxymethylsilane (179 g), toluene (300 g), and acetic acid (5 g) were added to a 1-L flask, and the mixture was stirred at 25°C for 20 minutes. The mixture was then heated to 60°C and reacted for 12 hours. The resulting crude reaction liquid was cooled to 25°C, and then washed three times with water (300 g). Chlorotrimethylsilane (70 g) was added to the washed crude reaction liquid, and the mixture was stirred at 25°C for 20 minutes. The mixture was then heated to 50°C and reacted for 12 hours. The resulting crude reaction liquid was cooled to 25°C, and then washed three times with water (300 g). Toluene was removed from the washed crude reaction liquid under reduced pressure to form a slurry, which was then dried overnight in a vacuum dryer to obtain a white organopolysiloxane compound as a siloxane component having T units.

[0076] <Preparation of Curable Composition> The obtained organopolysiloxane compound (31.5 g), WACKER TES 40 WN ETHYL-SILICATE (manufactured by Wacker Asahi Kasei Silicones Co., Ltd.) (3.5 g) as a siloxane component having Q units, and tetra-normal-butyl titanate ("Orgatix TA-21" manufactured by Matsumoto Fine Chemical Co., Ltd., metal content: 14.1% by mass) (0.496 g) as a metal compound were dissolved in toluene (special grade reagent, manufactured by Junsei Chemical Co., Ltd.) (81.7 g) and the solution was filtered using a filter with a pore size of 0.45 μm, thereby preparing the curable composition of Example 1.

[0077] <Manufacture of Light-Emitting Device> A PET film (Cosmoshine A4160, manufactured by Toyobo Co., Ltd., thickness 50 μm) was prepared as a temporary support for transfer. The prepared curable composition was applied to the flat surface of the PET film having a flat surface and an uneven surface, and heated at 120 ° C. for 10 minutes using a hot plate to form a film-like curable composition film. Thereafter, a glass lens was placed so that the bottom surface thereof was in contact with the curable composition film, and a 500 g weight was placed on the glass lens. The glass lens was heated on a hot plate at 80 ° C. for 30 minutes, and then the temperature was increased to 120 ° C. and heated for 60 minutes. After returning to room temperature, the PET film was peeled off, and the curable composition film was transferred to the bottom surface of the glass lens.

[0078] The glass lens onto which the curable composition film had been transferred was placed on the light-emitting element, a 1 kg weight was placed on the glass lens, and the glass lens was heated on a hot plate at 120°C for 30 minutes to soften the curable composition film, spreading the curable composition film over the entire bonding surface of the glass lens. The curable composition film was then cured by heating at 200°C for 30 minutes to form an adhesive layer with an average thickness of 2 μm that bonded the lens and the light-emitting element, thereby producing a light-emitting device of Example 1 having the light-emitting element, the adhesive layer, and the lens as shown in Figure 1.

[0079] <Evaluation> The absorbance ratio and thickness of the adhesive layer were measured and the adhesive strength, bubbles, and light resistance were evaluated as characteristics of the light emitting device according to the following procedures. The results are shown in Table 1.

[0080] <<Ratio of absorbance of adhesive layer (A１０５５ / A １２７０ ) >> The infrared absorption spectrum of the adhesive layer was obtained by total reflection measurement (ATR method) of infrared spectroscopy (FT-IR), and ATR correction was performed. －１ is the zero point, and 1270 cm －１ ±5cm －１ Maximum absorbance A １２７０ 1055 cm －１ ±10cm －１ Maximum absorbance A １０５５ The ratio (A １０５５ / A １２７０ ) was calculated.

[0081] <<Thickness of Adhesive Layer>> After removing the glass lens from the light-emitting element, scratches were made at any five locations on the bonding portion of the adhesive layer remaining on the bottom surface of the light-emitting element and / or the glass lens, and the step portion of the scratch was measured using a non-contact surface normality measuring device (PF-60, manufactured by Mitaka Kohki Co., Ltd.), and the height of the step was taken as the thickness of the adhesive layer (film thickness value).

[0082] The thickness of the adhesive layer was measured at any five points, and the average value was determined as the average thickness of the adhesive layer.

[0083] The maximum and minimum values ​​of the measured thickness are the maximum thickness T Ｍ and minimum thickness T ｍ In addition, the maximum thickness T Ｍ and minimum thickness T ｍ The difference between (T Ｍ -T ｍ ) was sought.

[0084] <<Adhesion Strength>> A load of 1 kgf was applied to the light-emitting element using a bond tester, and the occurrence of lens detachment was tested. Based on the number of lens detachments that occurred in 10 tests (n=10), evaluation was performed according to the following evaluation criteria. - Evaluation Criteria - ◎: No lens detachment occurred in 10 tests ○: Lens detachment occurred 1 to 4 times ×: Lens detachment occurred 5 or more times (outside the practical range)

[0085] <<Air Bubbles>> The adhesive layer of the light-emitting element after bonding was observed under a microscope from above the lens to check for the presence of microbubbles, and evaluated according to the following evaluation criteria. -Evaluation criteria- ◎: No bubbles present ○: Bubbles present in 20% or less of the observed field of view ×: Bubbles present in more than 20% but not more than 100% of the observed field of view (outside the practical range)

[0086] <<Light resistance>> Light-emitting element LED (280 nm wavelength, radiant flux 70 mW / cm ２ After 20 hours, the adhesive layer was checked for cracks and evaluated according to the following criteria: -Evaluation criteria- ◯: No cracks occurred ×: Cracks occurred

[0087] [Examples 2 to 10] Curable compositions and light-emitting devices of Examples 2 to 10 were produced and evaluated in the same manner as in Example 1, except that the mole percentages of T units and Q units in the silicone resin were changed as shown in Table 1. The results are shown in Table 1.

[0088] [Examples 11 to 14] Curable compositions and light-emitting devices of Examples 11 to 14 were produced and evaluated in the same manner as in Example 1, except that the mole percentages of T units and Q units in the silicone resin were changed as shown in Table 1. The results are shown in Table 1.

[0089]

[0090] [Evaluation Results] The evaluation results for Examples 1 to 14 are shown in Table 1. The results in Table 1 show that the smaller the ratio of Q units in the silicone resin used, the lower the adhesive strength, but the less likely bubbles are to form when heated during adhesion. On the other hand, the larger the ratio of Q units in the silicone resin used, the higher the adhesive strength, but the more likely bubbles are to form, showing a trade-off relationship.

[0091] When the ratio of T units to Q units (T / Q) of the silicone resin is 50 / 50 to 90 / 10, or when the absorbance ratio (A １０５５ / A １２７０It was found that when the T / Q ratio was 1.55 or more and 2.5 or less (Examples 1 to 10), a light-emitting device having an adhesive layer with excellent adhesiveness and light resistance and reduced bubbles could be manufactured. In particular, when the T / Q ratio was 80 / 20 (Examples 2, 5 to 10), the evaluations of "adhesion strength" and "bubbles" were good. In addition, the absorbance ratio (A １０５５ / A １２７０ ) it was confirmed that the composition of T units and Q units of a silicone resin can be evaluated.

[0092] Furthermore, a comparison of Examples 2, 5, and 10 revealed that the greater the average thickness of the adhesive layer, the greater the absolute amount of Q-oligomer in the curable composition, and the more likely bubbles are to be generated due to the generation of volatile components upon heating, but this is within a practical range. A comparison of Examples 2 and 6 to 9 revealed that when various metal elements were used, the adhesive layer was excellent in terms of adhesion and reduction of bubbles, and also provided light resistance.

[0093] Although the light-emitting device according to the present disclosure has been described above, the present disclosure is not limited to the above-described embodiments, etc. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. Naturally, these also fall within the technical scope of the present disclosure.

[0094] The following supplementary notes are disclosed regarding the above-described embodiments: [Supplementary Note 1] A light-emitting element, an optical glass member, and an adhesive layer that bonds the light-emitting element and the optical glass member, wherein the adhesive layer is made of RSiO ３／２ (wherein R represents an organic group), and an organosiloxy unit (T unit) represented by SiO ４／２ and a silicone resin having an organosiloxy unit (Q unit) represented by the following formula: －１ ±5cm －１ Maximum absorbance A １２７０ 1055 cm －１ ±10cm －１ Maximum absorbance A １０５５ The ratio (A １０５５ / A １２７０[Appendix 2] The light-emitting device according to Appendices 1, wherein R is a methyl group. [Appendix 3] The silicone resin is RSiO ３／２ (wherein R represents an organic group), and an organosiloxy unit (T unit) represented by SiO ４／２ and organosiloxy units (Q units) represented by the following formula: [Appendix 4] The light-emitting device according to any one of Appendices 1 to 3, wherein the adhesive layer further contains at least one metal element selected from 3d transition metals, 4d transition metals, lanthanoid metals, bismuth, aluminum, tin, and zinc. [Appendix 5] The light-emitting device according to any one of Appendices 1 to 4, wherein the adhesive layer has an average thickness of 4 μm or less. [Appendix 6] The adhesive layer has a maximum thickness T Ｍ and minimum thickness T ｍ The difference between (T Ｍ -T ｍ The light emitting device according to any one of Supplementary Notes 1 to 5, wherein the surface roughness of the adhesive layer at the bonding surface to the light emitting element is 0.01 nm or more and 50 nm or less. [Supplementary Note 8] The light emitting device according to any one of Supplementary Notes 1 to 7, wherein the indentation elastic modulus of the adhesive layer is 1 GPa or more and 10 GPa or less. [Supplementary Note 9] RSiO ３／２ (wherein R represents an organic group), and a siloxane component having an organosiloxy unit (T unit) represented by the formula: ４／２ and a siloxane component having an organosiloxy unit (Q unit) represented by the formula: wherein the curable composition is dried at 120°C for 30 minutes and then heated at 200°C for 30 minutes to obtain a cured product, and the infrared absorption spectrum of the cured product shows a peak at 1270cm －１ ±5cm －１ Maximum absorbance A １２７０ 1055 cm －１ ±10cm －１ Maximum absorbance A １０５５ The ratio (A １０５５ / A １２７０[Appendix 10] The curable composition according to Appendices 9, wherein R is a methyl group. [Appendix 11] The curable component in the curable composition is RSiO ３／２ (wherein R represents an organic group), and a siloxane component having an organosiloxy unit (T unit) represented by the formula: ４／２ and a siloxane component having organosiloxy units (Q units) represented by the following formula: [Appendix 12] The curable composition according to any one of Appendices 9 to 11, further comprising at least one metal element selected from 3d transition metals, 4d transition metals, lanthanoid metals, bismuth, aluminum, tin, and zinc. [Appendix 13] The curable composition according to any one of Appendices 9 to 12, which is in the form of a film. [Appendix 14] The curable composition according to any one of Appendices 9 to 13, which has an average thickness of 4 μm or less.

[0095] The disclosure of Japanese Patent Application No. 2024-091957, filed on June 6, 2024, is incorporated herein by reference in its entirety. In addition, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

[0096] REFERENCE SIGNS LIST 1 Light emitting device 2 Light emitting element 21 Light emitting surface (first interface) 3 Lens (optical glass member) 31 Opposing surface (second interface) 5 Adhesive layer

Claims

1. A light-emitting device comprising: a light-emitting element; an optical glass member; and an adhesive layer for bonding the light-emitting element and the optical glass member; wherein the adhesive layer is made of RSiO ３／２ wherein R represents an organic group; and an organosiloxy unit (T unit) represented by the formula: ４／２ and a silicone resin having an organosiloxy unit (Q unit) represented by the following formula: －１ ±5cm －１ Maximum absorbance A １２７０ 1055 cm －１ ±10cm －１ Maximum absorbance A １０５５ The ratio (A １０５５ / A １２７０ ) is 1.55 or more and 2.5 or less.

2. The light emitting device of claim 1, wherein R is a methyl group.

3. The silicone resin is RSiO ３／２ wherein R represents an organic group; and an organosiloxy unit (T unit) represented by the formula: ４／２ and organosiloxy units (Q units) represented by the following formula:

4. The light emitting device according to claim 1, wherein the adhesive layer further comprises at least one metal element selected from the group consisting of 3d transition metals, 4d transition metals, lanthanoid metals, bismuth, aluminum, tin, and zinc.

5. The light emitting device according to claim 1, wherein the adhesive layer has an average thickness of 4 μm or less.

6. Maximum thickness T of the adhesive layer Ｍ and minimum thickness T ｍ The difference between (T Ｍ -T ｍ 2. The light emitting device according to claim 1, wherein the thickness of the first electrode is 0.5 μm or less.

7. The light emitting device according to claim 1, wherein the adhesive layer has a surface roughness of 0.01 nm or more and 50 nm or less on the adhesive surface to be bonded to the light emitting element.

8. The light-emitting device according to claim 1, wherein the adhesive layer has an indentation modulus of elasticity of 1 GPa or more and 10 GPa or less.

9. RSiO ３／２ a siloxane component having organosiloxy units (T units) represented by the formula: ４／２ and a siloxane component having an organosiloxy unit (Q unit) represented by the formula: wherein the curable composition is dried at 120°C for 30 minutes and then heated at 200°C for 30 minutes to obtain a cured product, and the infrared absorption spectrum of the cured product shows a peak at 1270cm －１ ±5cm －１ Maximum absorbance A １２７０ 1055 cm －１ ±10cm －１ Maximum absorbance A １０５５ The ratio (A １０５５ / A １２７０ ) is 1.55 or more and 2.5 or less.

10. The curable composition of claim 9, wherein R is a methyl group.

11. The curable component in the curable composition is RSiO ３／２ a siloxane component having organosiloxy units (T units) represented by the formula: ４／２ and a siloxane component having organosiloxy units (Q units) represented by the following formula:

12. The curable composition according to claim 9, further comprising at least one metal element selected from the group consisting of 3d transition metals, 4d transition metals, lanthanoid metals, bismuth, aluminum, tin, and zinc.

13. The curable composition according to claim 9, which is in the form of a film.

14. The curable composition of claim 13, having an average thickness of 4 μm or less.

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