WO2022014186A1 - Electronic device and method for manufacturing electronic device - Google Patents

Abstract

An electronic device 1 comprises an electronic component 2, a substrate to which the electronic component 2 is mounted, and a protective cap 4 which is joined to the substrate 3 so as to house the electronic component 2 in the interior thereof. The protective cap 4 is provided with a frame part 6 comprising a first transparent inorganic material, and a lid part 7 covering one end opening of the frame part 6 and comprising a second transparent inorganic material. The frame part 6 and the substrate 3 are directly welded together by a weld section 9.

Description

Electronic device and manufacturing method of electronic device

The present invention relates to an electronic device and a method for manufacturing the electronic device.

Electronic devices equipped with electronic components such as LEDs have come to be used in various fields such as lighting and communication because of their long life and energy saving.

In this type of light emitting device, in order to protect the electronic component, the base material on which the electronic component is mounted may be covered with a protective cap so that the electronic component is housed inside.

For example, as disclosed in Patent Document 1, the protective cap includes a frame portion (second member) that surrounds the periphery of the light emitting element, and a lid portion (cover member) that covers one end opening of the frame portion. ..

International Publication No. 2015/190242

In many cases, the frame of the protective cap and the base material on which the electronic components are mounted are joined using a brazing material (for example, gold-tin solder). The base material is composed of metal or metal nitride ceramics, and is often a material having a high coefficient of expansion. On the other hand, the frame portion is made of a transparent inorganic material such as glass, and may be a material having a low coefficient of expansion. In such a case, the difference in the coefficient of thermal expansion between the base material and the frame portion becomes large, and it is difficult to select a brazing material that matches the coefficient of thermal expansion of both the base material and the frame portion. That is, when the coefficient of thermal expansion of the brazing material is matched with the coefficient of thermal expansion of the base material, the difference between the coefficient of thermal expansion of the frame portion and the brazing material becomes large, and when the coefficient of thermal expansion of the brazing material is matched with the frame portion, the base material is used. And the difference in the coefficient of thermal expansion of the brazing material becomes large. As a result, residual stress is generated in or near the joint portion between the base material and the frame portion, and breakage (for example, cracking such as a crack) is likely to occur. If the joint or the vicinity thereof is damaged in this way, the airtightness of the accommodation space for the electronic component is lowered, and the electronic component may be deteriorated.

An object of the present invention is to provide an electronic device capable of maintaining high airtightness.

The present invention, which was devised to solve the above problems, comprises an electronic component, a base material on which the electronic component is mounted, and a protective cap bonded to the base material so that the electronic component is housed inside. The electronic device provided includes a protective cap having a frame portion made of a first transparent inorganic material and a lid portion made of a second transparent inorganic material covering one end opening of the frame portion, and the frame portion and the base material. However, it is characterized by being directly welded. By doing so, since other members do not intervene between the frame portion and the base material, even if the difference between the coefficient of thermal expansion of the frame portion and the coefficient of thermal expansion of the base material is large to some extent, the frame portion and the base material Can be reliably joined.

In the above configuration, it is preferable that the frame portion and the lid portion are directly welded. By doing so, since other members (highly expanding brazing material, adhesive material, etc.) do not intervene between the frame portion and the lid portion, the difference between the thermal expansion coefficient of the frame portion and the thermal expansion coefficient of the lid portion. Even if the size is large to some extent, the frame and lid can be reliably joined.

In the above configuration, the first transparent inorganic material is preferably quartz glass. By doing so, the transmittance of ultraviolet rays in the lid portion is increased, which is particularly effective when the electronic component is an element that emits or receives ultraviolet rays. The term "quartz glass" refers to a non-crystal body containing synthetic quartz, fused silica, or the like and containing _{90% by mass or more of SiO 2.}

In the above configuration, the second transparent inorganic material is preferably a glass material having a softening point of 1000 ° C. or lower. By doing so, for example, when the frame portion and the base material are directly welded by laser bonding or the like, the frame portion is easily softened. Therefore, the frame portion side can be softened to shorten the joining time of the lid portion and the frame portion. For the same reason, for example, when the frame portion and the lid portion are directly welded by laser bonding or the like, the frame portion is easily softened, so that the bonding time between the frame portion and the lid portion can be shortened. Here, the "softening point" refers to a value measured based on the method of ASTMC338.

In the above configuration, the second transparent inorganic material may be quartz glass. By doing so, the transmittance of ultraviolet rays in the frame portion becomes high. Therefore, it is particularly effective when the electronic component is an element that emits or receives ultraviolet rays.

In the above configuration, the electronic component may be an ultraviolet LED.

The present invention, which was devised to solve the above problems, includes an electronic component, a base material on which the electronic component is mounted, and a protective cap bonded to the base material so that the electronic component is housed inside. A protective cap is provided with a frame portion made of a first transparent inorganic material and a lid portion made of a second transparent inorganic material that covers one end opening of the frame portion, and is based on the frame portion. It is characterized by comprising a joining step of directly welding the frame portion and the base material by irradiating the contact portion between the frame portion and the base material with a laser in a state where the material is in contact with the material. By doing so, since other members do not intervene between the frame portion and the base material, even if the difference between the coefficient of thermal expansion of the frame portion and the coefficient of thermal expansion of the base material is large to some extent, the frame portion and the base material Can be reliably joined. Further, since the contact portion between the frame portion and the base material is locally heated by the laser, a material having low heat resistance can be used for the components of the electronic device such as electronic parts.

In the above configuration, a joining step of directly welding the frame portion and the lid portion by irradiating the contact portion between the frame portion and the lid portion with a laser in a state where the frame portion and the lid portion are in contact is further provided. There is. By doing so, since other members do not intervene between the frame portion and the lid portion, even if the difference between the coefficient of thermal expansion of the frame portion and the coefficient of thermal expansion of the lid portion is large to some extent, the frame portion and the lid portion Can be reliably joined.

According to the present invention, it is possible to provide an electronic device capable of maintaining high airtightness.

It is sectional drawing which shows the electronic device which concerns on 1st Embodiment. FIG. 1 is a cross-sectional view taken along the line AA of FIG. It is a graph which shows the transmittance curve of BU-41 and quartz glass at a wavelength of 200-600 nm. It is sectional drawing which shows the manufacturing process of the electronic apparatus which concerns on 1st Embodiment. It is sectional drawing which shows the manufacturing process of the electronic apparatus which concerns on 1st Embodiment. It is sectional drawing which shows the manufacturing process of the electronic apparatus which concerns on 1st Embodiment. It is sectional drawing which shows the manufacturing process of the electronic apparatus which concerns on 1st Embodiment. It is sectional drawing which shows the manufacturing process of the electronic apparatus which concerns on 1st Embodiment. It is sectional drawing which shows the electronic device which concerns on 2nd Embodiment. It is sectional drawing which shows the electronic device which concerns on 3rd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. By assigning the same reference numerals to the corresponding components in each embodiment, duplicate description may be omitted. When only a part of the configuration is described in each embodiment, the configuration of the other embodiment described above can be applied to the other parts of the configuration. Further, not only the combination of the configurations specified in the description of each embodiment but also the configurations of a plurality of embodiments can be partially combined even if the combination is not specified.

(First Embodiment)
1 and 2 illustrate the electronic device 1 according to the first embodiment of the present invention.

The electronic device 1 according to the present embodiment includes an electronic component 2, a base material 3 on which the electronic component 2 is mounted, a protective cap 4 arranged on the base material 3 so as to accommodate the electronic component 2 inside, and a protective cap 4. It is provided with a joint portion 5 for joining the base material 3 and the protective cap 4. In the following description, for convenience, the base material 3 side is shown as the bottom and the protective cap 4 side is shown as the top, but the vertical direction is not limited to this.

The electronic component 2 is not particularly limited, and examples thereof include optical devices such as a laser module, an LED, an optical sensor, an image pickup element, and an optical switch. In the present embodiment, the electronic component 2 is an ultraviolet LED, and the electronic device 1 is a light emitting device.

The base material 3 is composed of, for example, metal, metal oxide ceramics, LTCC or metal nitride ceramics. Examples of the metal include copper and metallic silicon. Examples of the metal oxide ceramics include aluminum oxide. Examples of the LTCC include a sintered composite powder containing crystalline glass and a refractory filler. Examples of the metal nitride ceramics include aluminum nitride. In this embodiment, the base material 3 is made of aluminum nitride. The coefficient of thermal expansion of aluminum nitride in the temperature range of 30 to 380 ° C. is, for example, 46 × 10 ^-7 / ° C. Further, in the present embodiment, the base material 3 is a plate-like body in which both the upper surface 3a and the lower surface 3b are formed of a flat surface. The base material 3 may be provided with a recess in the portion of the upper surface 3a on which the electronic component 2 is mounted.

The protective cap 4 includes a frame portion 6, a lid portion 7 that covers one end opening of the frame portion 6, and a joint portion 8 that joins the frame portion 6 and the lid portion 7. It is preferable to form various functional films on the surface of the protective cap 4, and for example, it is preferable to form an antireflection film in order to reduce light reflection loss.

The frame portion 6 is a tubular body having a through hole H extending in the thickness direction (vertical direction) at the center. The frame portion 6 surrounds the periphery of the electronic component 2 housed in the space corresponding to the through hole H. In the illustrated example, the frame portion 6 is composed of a square cylinder, but may have another shape such as a cylinder. The inner wall surface 6c of the frame portion 6 shifts from the inside to the outside from the lower end surface 6b side to the upper end surface 6a side of the frame portion 6 in order to improve the extraction efficiency of ultraviolet rays through the lid portion 7. It is composed of inclined surfaces. The inner wall surface 6c may be a non-sloping surface (vertical surface). The through hole H can be formed by subjecting the original material of the frame portion 6 to etching processing, laser processing, sandblasting, or the like.

The frame portion 6 is made of the first transparent inorganic material. Examples of the first transparent inorganic material include quartz glass (silica glass) and glass materials other than quartz glass. Quartz glass has a high ultraviolet transmittance. Here, "transparent" in the first transparent inorganic material and the second transparent inorganic material (described later) means, for example, transmitting light emitted from an electronic component 2 composed of a light emitting element. More specifically, it means that the transmittance of light in the target wavelength range is 10% or more. The transmittance can be measured using UH4150 manufactured by Hitachi High-Tech Science Corporation.

When the frame portion 6 is made of a glass material other than quartz glass, it is preferable that the glass material is also ultraviolet transmissive glass. Hereinafter, a glass material other than quartz glass may be simply referred to as a glass material.

In the glass material of the frame portion 6, the transmittance at an optical path length of 0.7 mm and a wavelength of 200 nm is preferably 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more. Especially preferably 80% or more. Further, in the glass material of the frame portion 6, the transmittance at an optical path length of 0.7 mm and a wavelength of 250 nm is preferably 50% or more, 60% or more, 70% or more, and particularly preferably 80% or more. Further, in the glass material of the frame portion 6, when the transmittance at an optical path length of 0.7 mm and a wavelength of 250 nm is T ₂₅₀ and the transmittance at an optical path length of 0.7 mm and a wavelength of 300 nm is T ₃₀₀ , T ₂₅₀ / T _300. The value of is preferably 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, 0.85 or more, and particularly preferably 0.9 or more. .. By doing so, although the transmittance of ultraviolet rays is inferior to that of quartz glass, the light emitted from the electronic component 2 composed of the ultraviolet LED can be transmitted without any problem, and the efficiency of extracting ultraviolet rays is maintained at a high level. can. The "optical path length 0.7 mm" means that even when the thickness of the glass material is thin, an equivalent measurement sample having an optical path length of 0.7 mm is prepared and then used for measurement. The "transmittance at an optical path length of 0.7 mm and a wavelength of 200 nm" may be measured after preparing a measurement sample having a thickness of 0.7 mm, and after measuring the transmittance in the thickness direction of the glass material, the optical path A value converted to a length of 0.7 mm may be adopted.

In the glass material of the frame portion 6, the strain point is preferably 430 ° C. or higher, 460 ° C. or higher, 480 ° C. or higher, 500 ° C. or higher, 520 ° C. or higher, 530 ° C. or higher, 550 ° C. or higher, 600 ° C. or higher, particularly preferably 630. It is above ℃. If the distortion point is too low, distortion may occur in the frame portion 6 at the time of laser joining described later, but this can be suppressed by setting the distortion point within the above numerical range. Here, the "distortion point" is a value measured based on the method of ASTMC336.

In the glass material of the frame portion 6, the softening point is preferably 1000 ° C. or lower, 950 ° C. or lower, 900 ° C. or lower, 850 ° C. or lower, and particularly preferably 800 ° C. or lower. By doing so, when the frame portion 6 and the lid portion 7 and the frame portion 6 and the base material 3 are directly welded by laser bonding or the like, the frame portion 6 is easily softened, so that the bonding time can be shortened. can.

In the glass material of the frame portion 6, ^{the temperature at 10 2.5} dPa · s is preferably 1580 ° C. or lower, 1550 ° C. or lower, 1520 ° C. or lower, 1500 ° C. or lower, 1480 ° C. or lower, and particularly 1470 ° C. or lower. If the ^{temperature at 10 2.5} dPa · s is too high, the meltability is lowered and the manufacturing cost of glass is likely to rise. Here, the " ^{temperature at 10 2.5} dPa · s" can be measured by the platinum ball pulling method. The temperature at 10 ^2.5 dPa · s corresponds to the melting temperature, and the lower the temperature, the better the melting property.

In the glass material of the frame portion 6, the coefficient of thermal expansion in the temperature range of 30 to 380 ° C. is preferably 30 × 10 ^-7 / ° C. or higher, 40 × 10 ^-7 / ° C. or higher, 50 × 10 ^-7 / ° C. or higher, It is 60 × 10 ^-7 / ° C or higher, particularly preferably 70 × 10 ^-7 / ° C or higher. Further, in the glass material of the frame portion 6, the coefficient of thermal expansion in the temperature range of 30 to 380 ° C. is preferably 105 × 10 ^-7 / ° C. or less, 100 × 10 ^-7 / ° C. or less, 95 × 10 ^-7 / ° C. or less. Particularly preferably, it is 90 × 10 ^-7 / ° C or less. If the coefficient of thermal expansion is too low, it will be difficult to match the coefficient of thermal expansion of various members, especially glass frits. As a result, it becomes difficult to lower the melting point of the glass frit, which causes the temperature of the manufacturing process of the electronic device 1 to rise, and the performance of the electronic device 1 tends to deteriorate. On the other hand, if the coefficient of thermal expansion is too high, the frame portion 6 is likely to be damaged due to thermal shock. The coefficient of thermal expansion of quartz glass in the temperature range of 30 to 380 ° C. is, for example, 4.0 × 10 ^-7 / ° C. Here, the "coefficient of thermal expansion in the temperature range of 30 to 380 ° C." can be measured using, for example, a dilatometer.

The liquid phase temperature of the glass material of the frame portion 6 is preferably less than 1150 ° C., 1120 ° C. or lower, 1100 ° C. or lower, 1080 ° C. or lower, 1050 ° C. or lower, 1030 ° C. or lower, 980 ° C. or lower, 960 ° C. or lower, 950 ° C. or lower, Particularly preferably, it is 940 ° C. or lower. The liquid phase viscosity of the glass material of the frame portion 6 is preferably 10 ^4.0 dPa · s or more, 10 ^4.3 dPa · s or more, 10 ^4.5 dPa · s or more, 10 ^4.8 dPa · s or more, and 10 ^5.1 dPa · s or more. It is 10 ^5.3 dPa · s or more, particularly preferably 10 ^5.5 dPa · s or more. By doing so, the devitrification resistance is improved. Here, the "liquid phase temperature" is determined by passing the standard sieve 30 mesh (500 μm) and putting the glass powder remaining in 50 mesh (300 μm) into a platinum boat and holding it in a temperature gradient furnace for 24 hours, after which crystals are formed. It is a value measured by microscopic observation of the precipitation temperature. The "liquid phase viscosity" is a value obtained by measuring the viscosity of glass at the liquid phase temperature by the platinum ball pulling method.

The Young's modulus of the glass material of the frame portion 6 is preferably 55 GPa or more, 60 GPa or more, 65 GPa or more, and particularly preferably 70 GPa or more. If the Young's modulus is too low, the frame portion 6 is likely to be deformed, warped, or damaged. Here, "Young's modulus" is a value measured by the resonance method.

The glass material of the frame portion 6 has a glass composition of _{40% by mass, SiO 2} 50 to 80%, Al ₂ O ₃ + B ₂ O ₃ 1 to 45%, Li ₂ O + Na ₂ O + K ₂ O 0 to 25%, MgO + CaO + SrO + BaO 0. It is preferably ~ 25%. The reasons for limiting the content of each component as described above are shown below. In addition, in the description of the content of each component, the% display represents mass% unless otherwise specified. "Al ₂ O ₃ + B ₂ O ₃ " means the total amount of _{Al 2} O ₃ and B ₂ O _3. "Li ₂ O + Na ₂ O + K ₂ O" means the total amount of _{Li 2} O, Na ₂ O and K _{2 O.} "MgO + CaO + SrO + BaO" means the total amount of MgO, CaO, SrO and BaO.

SiO ₂ is a main component forming the skeleton of glass. The content of SiO ₂ is preferably 50 to 80%, 55 to 75%, 58 to 70%, and particularly preferably 60 to 68%. If _{the content of SiO 2} is too small, Young's modulus and acid resistance tend to decrease. On the other hand, _{if the content of SiO 2} is too high, the high-temperature viscosity becomes high and the meltability tends to decrease, and in addition, devitrified crystals such as cristobalite tend to precipitate and the liquidus temperature tends to rise. Become.

Al ₂ O ₃ and B ₂ O ₃ are components that enhance devitrification resistance. The content of Al ₂ O ₃ + B ₂ O ₃ is preferably 1 to 40%, 5 to 35%, 10 to 30%, and particularly preferably 15 to 25%. If _{the content of Al 2} O ₃ + B ₂ O ₃ is too low, the glass tends to be devitrified. On the other hand, _{if the content of Al 2} O ₃ + B ₂ O ₃ is too large, the component balance of the glass composition is impaired, and conversely, the glass tends to be devitrified.

Al ₂ O ₃ is a component that enhances Young's modulus and suppresses phase separation and devitrification. The content of Al ₂ O ₃ is preferably 1 to 20%, 3 to 18%, and particularly 5 to 16%. If _{the content of Al 2} O ₃ is too small, the Young's modulus tends to decrease, and the glass tends to undergo phase separation and devitrification. On the other hand, _{if the content of Al 2} O ₃ is too large, the high-temperature viscosity becomes high and the meltability tends to decrease.

B ₂ O ₃ is a component that enhances meltability and devitrification resistance, and is a component that improves the susceptibility to scratches and enhances strength. The content of B ₂ O ₃ is preferably 3 to 25%, 5 to 22%, 7 to 19%, and particularly 9 to 16%. If _{the content of B 2} O ₃ is too small, the meltability and devitrification resistance tend to decrease, and the resistance to hydrofluoric acid-based chemicals tends to decrease. On the other hand, _{if the content of B 2} O ₃ is too large, Young's modulus and acid resistance tend to decrease.

Li ₂ O, Na ₂ O and K ₂ O are components that lower the high temperature viscosity, significantly increase the meltability, and contribute to the initial melting of the glass raw material. The content of Li ₂ O + Na ₂ O + K ₂ O is preferably 0 to 25%, 1 to 20%, 4 to 15%, and particularly 7 to 13%. If _{the content of Li 2} O + Na ₂ O + K ₂ O is too small, the meltability tends to decrease. On the other hand, _{if the content of Li 2} O + Na ₂ O + K ₂ O is too large, the coefficient of thermal expansion may become unreasonably high.

Li ₂ O is a component that lowers the high-temperature viscosity, remarkably increases the meltability, and contributes to the initial melting of the glass raw material. The content of Li ₂ O is preferably 0 to 5%, 0 to 3%, 0-1%, and particularly preferably 0 to 0.1%. If _{the content of Li 2} O is too small, the meltability tends to decrease and the coefficient of thermal expansion may become unreasonably low. On the other hand, if the Li ₂ O content is too high, the glass tends to be phase-separated.

Na ₂ O is a component that lowers the high-temperature viscosity, significantly enhances the meltability, and contributes to the initial melting of the glass raw material. It is also a component for adjusting the coefficient of thermal expansion. The content of Na ₂ O is preferably 0 to 25%, 1 to 20%, 3 to 18%, 5 to 15%, and particularly preferably 7 to 13%. If the Na ₂ O content is too low, the meltability tends to decrease and the coefficient of thermal expansion may become unreasonably low. On the other hand, if the Na ₂ O content is too high, the coefficient of thermal expansion may become unreasonably high.

K ₂ O is a component that lowers the high-temperature viscosity, remarkably increases the meltability, and contributes to the initial melting of the glass raw material. It is also a component for adjusting the coefficient of thermal expansion. The content of K ₂ O is preferably 0 to 15%, 0.1 to 10%, and particularly preferably 1 to 5%. If _{the content of K 2} O is too high, the coefficient of thermal expansion may become unreasonably high.

MgO, CaO, SrO and BaO are components that lower the high temperature viscosity and increase the meltability. The content of MgO + CaO + SrO + BaO is preferably 0 to 25%, 0 to 15%, 0.1 to 12%, and 1 to 5%. If the content of MgO + CaO + SrO + BaO is too large, the glass tends to be devitrified.

MgO is a component that lowers high-temperature viscosity and enhances meltability, and is a component that significantly increases Young's modulus among alkaline earth metal oxides. The content of MgO is preferably 0 to 10%, 0 to 8%, 0 to 5%, and particularly preferably 0 to 1%. If the content of MgO is too large, the devitrification resistance tends to decrease.

CaO is a component that lowers high-temperature viscosity and significantly increases meltability. Further, among alkaline earth metal oxides, the raw material to be introduced is relatively inexpensive, so that it is a component that reduces the raw material cost. The CaO content is preferably 0 to 15%, 0.5 to 10%, and particularly preferably 1 to 5%. If the CaO content is too high, the glass tends to be devitrified. If the CaO content is too low, it becomes difficult to enjoy the above effects.

SrO is a component that enhances devitrification resistance. The content of SrO is preferably 0 to 7%, 0 to 5%, 0 to 3%, and particularly preferably less than 0 to 1%. If the content of SrO is too high, the glass tends to be devitrified.

BaO is a component that enhances devitrification resistance. The content of BaO is preferably 0 to 7%, 0 to 5%, 0 to 3%, and less than 0-1%. If the BaO content is too high, the glass tends to be devitrified.

In addition to the above components, other components may be introduced as optional components. The content of the components other than the above components is preferably 10% or less, 5% or less, particularly 3% or less in total, from the viewpoint of accurately enjoying the effects of the present invention.

ZnO is a component that enhances meltability, but if it is contained in a large amount in the glass composition, the glass tends to be devitrified. Therefore, the ZnO content is preferably 0 to 5%, 0 to 3%, 0 to 1%, less than 0-1%, and particularly preferably 0 to 0.1%.

ZrO ₂ is a component that enhances acid resistance, but if it is contained in a large amount in the glass composition, the glass tends to be devitrified. Therefore, _{the content of ZrO 2} is preferably 0 to 5%, 0 to 3%, 0 to 1%, 0 to 0.5%, and particularly preferably 0.001 to 0.2%.

Fe ₂ O ₃ and TiO ₂ are components that reduce the transmittance in the deep ultraviolet region. The content of Fe ₂ O ₃ + TiO ₂ is preferably 100 ppm or less, 80 ppm or less, 60 ppm or less, 0.1 to 40 ppm or less, and particularly preferably 1 to 20 ppm. If _{the content of Fe 2} O ₃ + TiO ₂ is too high, the glass is colored and the transmittance in the deep ultraviolet region tends to decrease. If _{the content of Fe 2} O ₃ + TiO ₂ is too small, a high-purity glass raw material must be used, which leads to an increase in batch cost. In addition, "Fe ₂ O ₃ + TiO ₂ " means the total amount of _{Fe 2} O ₃ and TiO _2.

Fe ₂ O ₃ is a component that lowers the transmittance in the deep ultraviolet region. The content of Fe ₂ O ₃ is preferably 100 ppm or less, 80 ppm or less, 60 ppm or less, 40 ppm or less, 20 ppm or less, 10 ppm or less, and particularly preferably 1 to 8 ppm. If _{the content of Fe 2} O ₃ is too high, the glass is colored and the transmittance in the deep ultraviolet region tends to decrease. If _{the content of Fe 2} O ₃ is too small, a high-purity glass raw material must be used, which leads to an increase in batch cost.

Fe ions in iron oxide exist in the state of ^{Fe 2+} or Fe ^3+. If ^{the proportion of Fe 2+} is too small, the transmittance in deep ultraviolet rays tends to decrease. Therefore, ^{the mass ratio of Fe 2+} / (Fe ²⁺ + Fe ³⁺ ) in iron oxide is preferably 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, and particularly preferably 0. 5 or more.

TiO ₂ is a component that reduces the transmittance in the deep ultraviolet region. The content of TiO ₂ is preferably 100 ppm or less, 80 ppm or less, 60 ppm or less, 40 ppm or less, 20 ppm or less, 10 ppm or less, and particularly preferably 0.5 to 5 ppm. If _{the content of TiO 2} is too high, the glass will be colored and the transmittance in the deep ultraviolet region tends to decrease. If _{the content of TiO 2} is too small, a high-purity glass raw material must be used, which leads to an increase in batch cost.

Sb ₂ O ₃ is a component that acts as a clarifying agent. The content of Sb ₂ O ₃ is preferably 1000 ppm or less, 800 ppm or less, 600 ppm or less, 400 ppm or less, 200 ppm or less, 100 ppm or less, and particularly preferably less than 50 ppm. If _{the content of Sb 2} O ₃ is too high, the transmittance in the deep ultraviolet region tends to decrease.

SnO ₂ is a component that acts as a clarifying agent. The SnO ₂ content is preferably 2000 ppm or less, 1700 ppm or less, 1400 ppm or less, 1100 ppm or less, 800 ppm or less, 500 ppm or less, 200 ppm or less, and particularly preferably 100 ppm or less. If the SnO ₂ content is too high, the transmittance in the deep ultraviolet region tends to decrease.

F ₂ , Cl ₂ and SO ₃ are components that act as clarifying agents. The content of F ₂ + Cl ₂ + SO ₃ is preferably 10 to 10000 ppm. Suitable lower limit range of F ₂ + Cl ₂ + SO ₃ is 10 ppm or more, 20 ppm or more, 50 ppm or more, 100 ppm or more, 300 ppm or more, especially 500 ppm or more, and suitable upper limit range is 3000 ppm or less, 2000 ppm or less, 1000 ppm or less, especially 800 ppm or less. Is. Further, _{the suitable lower limit range of each of F 2} , Cl ₂ and SO ₃ is 10 ppm or more, 20 ppm or more, 50 ppm or more, 100 ppm or more, 300 ppm or more, particularly 500 ppm or more, and the suitable upper limit range is 3000 ppm or less, 2000 ppm or less. It is 1000 ppm or less, particularly 800 ppm or less. If the content of these components is too small, it becomes difficult to exert the clarification effect. On the other hand, if the content of these components is too large, the clarified gas may remain in the glass as bubbles. In addition, "F ₂ + Cl ₂ + SO ₃ " means the total amount of _{F 2} , Cl ₂ and SO _3.

For the glass material of the frame portion 6, for example, various glass raw materials are mixed to obtain a glass batch, and then the glass batch is melted, and the obtained molten glass is clarified and homogenized and molded into a predetermined shape. Can be made with.

In the process of manufacturing the glass material of the frame portion 6, it is preferable to use a reducing agent as a part of the glass raw material. ^{By doing so, Fe 3+} contained in the glass is reduced, and the transmittance in deep ultraviolet rays is improved. As the reducing agent, materials such as wood powder, carbon powder, metallic aluminum, metallic silicon, and aluminum fluoride can be used, and among them, metallic silicon and aluminum fluoride are preferable.

In the process of manufacturing the glass material of the frame portion 6, it is preferable to use metallic silicon as a part of the glass raw material, and the addition amount thereof is 0.001 to 3% by mass, 0.005, based on the total mass of the glass batch. It is preferably from 2% by mass, 0.01 to 1% by mass, and particularly preferably 0.03 to 0.1% by mass. If the amount of metallic silicon added is too small, Fe ³⁺ contained in the glass is not reduced, and the transmittance in deep ultraviolet rays tends to decrease. On the other hand, if the amount of metallic silicon added is too large, the glass tends to be colored brown.

_{It is also preferable to use aluminum fluoride (AlF 3} ) as a part of the glass raw material, and the addition amount thereof is 0.01 to 5% by mass and 0.05 to 5% by mass in terms of _{F 2 with} respect to the total mass of the glass batch. 4% by mass, 0.1 to 3% by mass, 0.2 to 2% by mass, and 0.3 to 1% by mass are preferable. On the other hand, if the amount of aluminum fluoride added is too large, F ₂ gas may remain in the glass as bubbles. If the amount of aluminum fluoride added is too small, Fe ³⁺ contained in the glass is not reduced, and the transmittance in deep ultraviolet rays tends to decrease.

In the manufacturing process of the glass material of the frame portion 6, it is preferable to form a flat plate shape by a down draw method, particularly an overflow down draw method. In the overflow down draw method, molten glass is overflowed from both sides of a heat-resistant gutter-shaped structure, and the overflowed molten glass is merged at the lower apex end of the gutter-shaped structure and stretched downward to form a glass plate. How to do it. In the overflow down draw method, the surface of the glass plate, which should be the surface, does not come into contact with the gutter-shaped refractory and is formed in a free surface state. Therefore, it becomes easy to manufacture a thin glass plate, and it is possible to reduce the variation in plate thickness without polishing the surface. As a result, the manufacturing cost of the glass plate can be reduced. The structure and material of the gutter-shaped structure are not particularly limited as long as they can achieve desired dimensions and surface accuracy. Further, the method of applying a force when performing downward stretch molding is not particularly limited. For example, a method of rotating and stretching a heat-resistant roll having a sufficiently large width in contact with the glass may be adopted, or a plurality of pairs of heat-resistant rolls may be brought into contact with only the vicinity of the end face of the glass. You may adopt the method of letting and stretching.

As a method for forming the glass material of the frame portion 6, for example, a slot down method, a redraw method, a float method, or the like can be adopted in addition to the down draw method.

Specifically, as the glass material of the frame portion 6, for example, BU-41 manufactured by Nippon Electric Glass Co., Ltd. can be used. The coefficient of thermal expansion of BU-41 in the temperature range of 30 to 380 ° C. is, for example, 42 × 10 ^-7 / ° C.

The thickness (vertical dimension) of the frame portion 6 is preferably larger than that of the electronic component 2, preferably 0.01 to 1 mm larger than that of the electronic component 2, and more preferably 0.05 to 0.5 mm larger. Most preferably, it is 0.1 to 0.2 mm larger.

The lid portion 7 is made of a second transparent inorganic material. As the second transparent inorganic material, those exemplified as the first transparent inorganic material can be similarly applied. The second transparent inorganic material may be the same material as the first transparent inorganic material, or may be a different material. However, from the viewpoint of the efficiency of extracting ultraviolet rays, it is preferable that the lid portion 7 is made of quartz glass. In this embodiment, the lid portion 7 is made of quartz glass. Further, in the present embodiment, the lid portion 7 is a plate-like body in which both the upper surface 7a and the lower surface 7b are formed of a flat surface.

The thickness (vertical dimension) of the lid portion 7 is preferably 0.1 to 1.0 mm, more preferably 0.2 to 0.8 mm, and preferably 0.3 to 0.6 mm. Most preferred.

In the present embodiment, the joint portion 5 for joining the frame portion 6 and the base material 3 is formed of a welded portion 9 in which the frame portion 6 and the base material 3 are directly welded. Similarly, the joint portion 8 for joining the frame portion 6 and the lid portion 7 is also formed from the welded portion 10 in which the frame portion 6 and the lid portion 7 are directly welded. The welded portions 9 and 10 are formed by laser bonding.

Specifically, the welded portion 9 is formed by melting at least one of the frame portion 6 and the base material 3 in the laser irradiation region and then solidifying the fused portion. That is, it is preferable that the welded portion 9 is composed of, for example, at least one material of the frame portion 6 and the base material 3, and substantially does not contain any material other than the frame portion 6 and the base material 3. Similarly, the welded portion 10 is formed by melting at least one of the frame portion 6 and the lid portion 7 in the laser irradiation region and then solidifying the fused portion. That is, it is preferable that the welded portion 9 is composed of, for example, at least one material of the frame portion 6 and the lid portion 7, and substantially does not contain any material other than the frame portion 6 and the lid portion 7.

A plurality of welded portions 9 and 10 are formed concentrically along the through hole H (two in the example), but may be one. The plurality of welded portions 9 and 10 are separated from each other in the radial direction, but may overlap each other in the radial direction. Each of the welded portions 9 and 10 is formed in a square ring shape in a plan view, but is not limited to this, and may be formed in an annular shape or other ring shape.

The welded portion 9 is formed so as to continuously straddle the frame portion 6 and the base material 3 in the thickness direction. Similarly, the welded portion 10 is formed so as to continuously straddle the frame portion 6 and the lid portion 7 in the thickness direction. In the present embodiment, there is no interface between the frame portion 6 and the base material 3 inside the welded portion 9, and there is an interface between the frame portion 6 and the lid portion 7 inside the welded portion 10. There is no. Of course, the interface may remain inside the welded portions 9 and 10.

The width S1 of the welded portions 9 and 10 is preferably 10 to 200 μm, more preferably 10 to 100 μm, and most preferably 10 to 50 μm. The thickness S2 of the welded portions 9 and 10 is preferably 10 to 200 μm, more preferably 10 to 150 μm, and most preferably 10 to 100 μm.

The maximum value of the residual stress in the plane direction of the welded portions 9 and 10 is preferably 10 MPa or less, more preferably 7 MPa or less, and most preferably 5 MPa or less. The maximum value of residual stress in the plane direction is the birefringence (unit: nm) near the joint using a birefringence measuring machine: ABR-10A manufactured by Uniopt Co., Ltd. on a glass plate having dimensions of 10 mm × 10 mm or more. However, it is the maximum value when converted to residual stress in the plane direction. Further, it is possible to estimate the residual stress value in the glass plate by measuring the optical birefringence, that is, the optical path difference of the orthogonal linear polarized waves, and the deviation stress F (MPa) generated by the residual stress is , F = D / CW. "D" is the optical path difference (nm), "W" is the distance (cm) through which the polarized wave has passed, and "C" is the photoelastic constant (proportional constant), which is usually 20 to 40 (nm / nm /). It becomes a value of cm) / (MPa). The residual stress in the plane direction includes tensile stress and compressive stress, but in the above, the absolute values of both are evaluated.

FIG. 3 shows the transmittance curves of BU-41 (manufactured by Nippon Electric Glass Co., Ltd.) and quartz glass at a wavelength of 200 to 600 nm. As shown in the figure, quartz glass has a transmittance of 90% or more in the deep ultraviolet region (for example, a wavelength region of 200 to 350 nm) without a decrease in transmittance due to an increase in thickness. On the other hand, BU-41 has a transmittance of 84% or more at a thickness of 0.2 mm and a transmittance of 70% or more at a thickness of 0.5 mm in the deep ultraviolet region. That is, BU-41 has a good transmittance in the deep ultraviolet region, although it is slightly inferior to quartz glass. In the state of the electronic device (light emitting device) 1, specifically, when the lid portion 7 and the frame portion 6 are both made of quartz glass having a thickness of 0.6 mm, the ultraviolet ray extraction efficiency (the electronic component (ultraviolet LED) 2). The output magnification) is 89% on average, and the ultraviolet extraction efficiency is 88% on average when the lid 7 is made of quartz glass with a thickness of 0.6 mm and the frame 6 is made of BU-41 with a thickness of 0.6 mm. Met. Therefore, even if the lid portion 7 is made of quartz glass and the frame portion 6 is made of a glass material having ultraviolet light transmittance other than quartz glass (for example, BU-41), the efficiency of extracting light in the ultraviolet region is at a high level. Can be maintained at. However, from the viewpoint of improving the efficiency of taking out ultraviolet rays, it is preferable that both the lid portion 7 and the frame portion 6 are made of quartz glass.

4 to 7 illustrate the manufacturing method of the electronic device 1 according to the first embodiment of the present invention.

The manufacturing method of the electronic device 1 according to the present embodiment includes a first joining step of joining the lid portion 7 and the frame portion 6 in order to obtain a protective cap 4, and protection of the base material 3 on which the electronic component 2 is mounted. It is provided with a second joining step for joining the cap 4.

In the first joining step, first, as shown in FIG. 4, the lid portion 7 and the frame portion 6 are prepared. Next, the lower surface 7b of the lid portion 7 and the upper end surface 6a of the frame portion 6 are brought into direct contact with each other. In this state, as shown in FIG. 5, the laser irradiation device 11 concentrates and irradiates the laser L on the contact portion between the lid portion 7 and the frame portion 6. The laser L irradiates from at least one side of the lid portion 7 and the frame portion 6. In the present embodiment, the laser L is irradiated from the lid portion 7 side. As a result, the contact portion is welded to form the welded portion 10, and the frame portion 6 and the lid portion 7 are joined by the welded portion 10. By doing so, since other members do not intervene between the frame portion 6 and the lid portion 7, even if the difference between the coefficient of thermal expansion of the frame portion 6 and the coefficient of thermal expansion of the lid portion 7 is large to some extent, the frame The portion 6 and the lid portion 7 can be reliably joined.

As shown in FIG. 6, the laser L is scanned outside the through hole H so as to draw an annular orbit T along the through hole H. In this case, the laser L is scanned so that its irradiation region R goes around the annular orbit T while overlapping on the annular orbit T. Alternatively, the laser L is scanned so as to orbit the annular orbit T a plurality of times. When a plurality of welded portions 10 are formed concentrically, a plurality of annular orbitals T for scanning the laser L are also set concentrically.

Further, a joint portion may be formed in a frame shape by crossing four straight lines in a grid shape so as to surround the through hole H. As a result, a plurality of protective caps 4 can be manufactured at one time, so that the manufacturing efficiency of the electronic device 1 can be improved.

In the second joining step, first, as shown in FIG. 7, the protective cap 4 obtained in the first joining step and the base material 3 on which the electronic component 2 is mounted are prepared. Next, the lower end surface 6b of the frame portion 6 and the upper surface 3a of the base material 3 are brought into direct contact with each other. In this state, as shown in FIG. 8, the laser irradiation device 11 condenses and irradiates the contact portion between the frame portion 6 and the base material 3 with the laser L. The laser L is irradiated from the frame portion 6 side of the frame portion 6 and the base material 3 that transmits the laser L. As a result, the contact portion is welded to form the welded portion 9, and the frame portion 6 and the base material 3 are joined by the welded portion 9. By doing so, since other members do not intervene between the frame portion 6 and the base material 3, even if the difference between the coefficient of thermal expansion of the frame portion 6 and the coefficient of thermal expansion of the base material 3 is large to some extent, the frame The portion 6 and the base material 3 can be reliably joined.

The arithmetic average roughness Ra of each of the lower surface 7b of the lid portion 7, the upper end surface 6a of the frame portion 6, the lower end surface 6b of the frame portion 6 and the upper surface 3a of the base material 3 is preferably 2.0 nm or less. It is more preferably 9.0 nm or less, further preferably 0.5 nm or less, and most preferably 0.2 nm or less. The arithmetic mean roughness Ra means a value measured by a method based on JIS B0601: 2001. By doing so, the lid portion 7 and the frame portion 6, and the frame portion 6 and the base material 3 are brought into close contact with each other by the intramolecular force (optical contact) between the bonding surfaces, so that the handleability before laser bonding is improved.

As the laser L, an ultrashort pulse laser having a pulse width on the order of picoseconds or femtoseconds is preferably used.

The wavelength of the laser L is not particularly limited as long as it passes through the glass member, but is preferably 400 to 1600 nm, more preferably 500 to 1300 nm, for example. The pulse width of the laser L is preferably 10 ps or less, more preferably 5 ps or less, and most preferably 200 fs to 3 ps. The focusing diameter of the laser L is preferably 50 μm or less, more preferably 30 μm or less, and preferably 20 μm or less.

The repetition frequency of the laser L needs to be such that continuous heat accumulation is generated, and specifically, it is preferably 100 kHz or more, more preferably 200 kHz or more, and more preferably 500 kHz or more. Is more preferable.

Further, it is preferable to use a method (burst mode) in which one pulse is distributed to a plurality of pulses and the pulse interval is further shortened to irradiate. As a result, heat accumulation is likely to occur, and the joint portion 8 can be stably formed.

(Second embodiment)
FIG. 9 illustrates the electronic device 1 according to the second embodiment of the present invention. In the second embodiment, the configuration of the joint portion 8 for joining the frame portion 6 and the lid portion 7 is different from that in the first embodiment.

In the present embodiment, the frame portion 6 and the lid portion 7 are made of quartz glass. The joint portion 8 is composed of an adhesive layer 21. That is, the frame portion 6 and the lid portion 7 are not in direct contact with each other, and the adhesive layer 21 is interposed between them. The adhesive layer 21 is formed, for example, by firing an adhesive material.

The coefficient of thermal expansion of the adhesive layer 21 in the temperature range of 30 to 380 ° C. is −25 × 10 ^-7 to 25 × 10 ^-7 / ° C. and −20 × 10 ^-7 to 20 × 10 ^-7 / ° C. It is preferably −15 × 10 ^-7 to 15 × 10 ^-7 / ° C, more preferably −10 × 10 ^-7 to 10 × 10 ^-7 / ° C, and most preferably −10 × 10 -7 to 10 × 10 -7 / ° C. The coefficient of thermal expansion of quartz glass in the temperature range of 30 to 380 ° C. is, for example, 4.0 × 10 ^-7 / ° C. Therefore, if the adhesive layer 21 having the above-mentioned coefficient of thermal expansion is used, the coefficient of thermal expansion of the frame portion 6 and the lid portion 7 made of a material having a low coefficient of expansion such as quartz glass and the coefficient of thermal expansion of the adhesive layer 21 are matched. Can be made to. As a result, even if the adhesive layer 21 is used, the residual stress generated in or near the adhesive layer 21 can be reduced, and damage (cracks, etc.) of the protective cap 4 can be suppressed.

The thickness of the adhesive layer 21 is not particularly limited, but if the thickness of the adhesive layer 21 is too small, the mechanical strength of the adhesive layer 21 tends to decrease. On the other hand, if the thickness of the adhesive layer 21 is too large, the residual stress in the adhesive layer 21 may increase and the mechanical strength may decrease. Furthermore, the size of the protective cap 4 and the electronic device 1 tends to be large. Therefore, the thickness of the adhesive layer 21 is preferably 10 μm to 100 μm, more preferably 20 μm to 80 μm, and most preferably 30 μm to 60 μm.

The adhesive layer 21 preferably contains glass. By doing so, the heat resistance and airtightness of the adhesive layer 21 can be improved. In particular, when the adhesive layer 21 contains crystallized glass, it becomes easy to reduce the expansion, and it becomes easy to match the coefficient of thermal expansion with the frame portion 6 and the lid portion 7 made of quartz glass. Specifically, the adhesive layer 21 preferably contains a β-quartz solid solution which is a low expansion crystal. The content of the β-quartz solid solution in the adhesive layer 21 is preferably 75 to 99% by mass, 80 to 97% by mass, and particularly preferably 85 to 95% by mass. If the content of the β-quartz solid solution is too small, it tends to be difficult to reduce the expansion of the adhesive layer 21. On the other hand, if the content of the β-quartz solid solution is too large, the fluidity at the time of joining tends to decrease. The adhesive layer 21 containing the crystallized glass is obtained by heat-treating the adhesive material (sealing material) containing the crystalline glass.

Specific examples of the adhesive layer 21, a composition, in _{mol%, SiO 2 48 ~ 75%} , Al 2 O 3 5 ~ 25%, Li 2 O 5 ~ 30%, B 2 O 3 5 ~ 23%, ZnO Those containing glass containing 0 to 10% can be mentioned. In particular, as a composition, in mol%, SiO ₂ 48 to 75%, Al ₂ O ₃ 5 to 25%, Li ₂ O 5 to 30%, B ₂ O ₃ 10 to 23% (however, 10% is not included), Glass containing 0 to 2.5% of ZnO (but not containing 2.5%) is preferable. The reason for adopting such a composition will be described below. In the following description of the content of each component, "%" means "mol%" unless otherwise specified.

SiO ₂ is a component forming a glass skeleton and is a component of a β-quartz solid solution. The content of SiO ₂ is preferably 48 to 75%, 53 to 70%, and particularly preferably 58 to 65%. If _{the content of SiO 2} is too small, the amount of β-quartz solid solution deposited is small, and it becomes difficult to obtain low thermal expansion characteristics. On the other hand, if the amount of SiO ₂ is too large, the softening point rises, so that the softening fluidity due to the heat treatment at the time of joining (sealing) tends to decrease.

Al ₂ O ₃ is a component of β-quartz solid solution. The content of Al ₂ O ₃ is preferably 5 to 25%, 7 to 15%, and particularly preferably 7 to 13%. If _{the content of Al 2} O ₃ is too small, the amount of β-quartz solid solution deposited is small, and it becomes difficult to obtain low thermal expansion characteristics. On the other hand, if the amount of Al ₂ O ₃ is too large, the softening point rises, so that the softening fluidity due to the heat treatment at the time of joining tends to decrease.

Li ₂ O is a component of the β-quartz solid solution and is a component that lowers the softening point. The content of Li ₂ O is preferably 5 to 30%, 10 to 25%, and particularly preferably 10 to 20%. If _{the content of Li 2} O is too small, the amount of β-quartz solid solution deposited will be small, and it will be difficult to obtain low thermal expansion characteristics. In addition, since the softening point rises, the softening fluidity due to the heat treatment at the time of joining tends to decrease. On the other hand, _{if the content of Li 2 O is too large, the content of Li 2} O in the residual glass after the heat treatment increases, and the coefficient of thermal expansion of the residual glass increases, so that it is difficult to obtain low thermal expansion characteristics as a result. Become.

B ₂ O ₃ is a component that forms a glass skeleton and is a component that lowers the softening point. The content of B ₂ O ₃ is preferably 5 to 23%, 10 to 23% (but not including 10%), 12 to 16%, and particularly preferably 13 to 15%. If _{the content of B 2} O ₃ is too small, the softening point rises and the difference between the softening point and the crystallization temperature becomes small. Therefore, crystals tend to precipitate before the softening flow due to the heat treatment at the time of joining, and the fluidity tends to decrease. On the other hand, _{if the content of B 2} O ₃ is too large, the ratio of the residual glass phase after the heat treatment increases (the amount of the β-quartz solid solution precipitated decreases), and the thermal expansion coefficient of the residual glass phase also increases. Therefore, as a result, it becomes difficult to obtain low thermal expansion characteristics.

By appropriately adjusting the ratio of each content of B ₂ O ₃ and Li ₂ O, it becomes easy to obtain low thermal expansion characteristics. Specifically, _{it is preferable to adjust the value of B 2} O ₃ / Li ₂ O to 0.5 to 1, 0.7 to 1, particularly 0.8 to 1. In addition, "B ₂ O ₃ / Li ₂ O" means the molar ratio of each content _{of B 2} O ₃ and Li _{2 O.}

ZnO is a component that improves weather resistance. In addition, it has the effect of improving the softening fluidity due to the heat treatment at the time of joining. The ZnO content is preferably 0 to 10%, 0 to 2.5% (but not including 2.5%), and particularly preferably 0 to 2%. If the ZnO content is too high, the amount of β-quartz solid solution deposited is small, and dissimilar crystals such as Zn-Al crystals that do not contribute to low expansion are likely to precipitate. In addition, the coefficient of thermal expansion of the residual glass after heat treatment tends to be high. As a result, the coefficient of thermal expansion tends to be large.

It should be noted that MgO, CaO, SrO or BaO may be contained as a component for improving weather resistance. These components also have the effect of improving the softening fluidity due to the heat treatment at the time of joining. The content of MgO + CaO + SrO + BaO is preferably 0 to 10%, 0 to 5%, and particularly preferably 0.1 to 2%. If the content of MgO + CaO + SrO + BaO is too large, the amount of β-quartz solid solution deposited tends to be small, and the coefficient of thermal expansion of the residual glass phase after heat treatment tends to be high. As a result, the coefficient of thermal expansion tends to be high.

_{Further, La 2} O ₃ , ZrO ₂ or Bi ₂ O ₃ may be contained as a component that also improves the weather resistance. Of these, ZrO ₂ and Bi ₂ O ₃ also have the effect of improving the softening fluidity due to the heat treatment during joining. The content of La ₂ O ₃ + ZrO ₂ + Bi ₂ O ₃ is preferably 0 to 10%, 0 to 5%, and particularly preferably 0.1 to 2%. If _{the content of La 2} O ₃ + ZrO ₂ + Bi ₂ O ₃ is too large, the amount of β-quartz solid solution deposited tends to be small, and the coefficient of thermal expansion of the residual glass phase after heat treatment tends to be high. In particular, _{if the content of La 2} O ₃ is too large, heterogeneous crystals such as La-B crystals that do not contribute to the reduction of expansion tend to precipitate. As a result, the coefficient of thermal expansion tends to be high. In addition, "La ₂ O ₃ + ZrO ₂ + Bi ₂ O ₃ " means the total amount of _{La 2} O ₃ , ZrO ₂ and Bi ₂ O _3.

_{In addition to the above components, Na 2} O, K ₂ O, MnO, P ₂ O ₅ , MoO ₂ , TiO ₂ , V ₂ O _{5 and the} like are added in a total amount of 30% or less as long as the effects of the present invention are not impaired. It can be contained in the range of 20% or less, further 10% or less.

The adhesive layer 21 may contain a refractory filler powder for adjusting the coefficient of thermal expansion. The content of the refractory filler is preferably 0 to 30% by mass, 0.1 to 20% by mass, and particularly preferably 1 to 10% by mass. If the content of the refractory filler powder is too large, the bondability to the member to be joined tends to decrease.

Fire-resistant filler powders include cordierite, willemite, alumina, zirconium phosphate, zircone, zirconia, tin oxide, mullite, silica, β-eucriptite, β-spojumen, β-quartz solid solution, zirconium tungstate phosphate. Etc. can be used.

The adhesive material constituting the adhesive layer 21 is arranged between the frame portion 6 and the lid portion 7 in the form of powder, green compact, paste or the like. When the adhesive is used as a paste, for example, a paste containing a powder of crystalline glass, a resin and a solvent is applied. For the application of the paste, for example, a dispenser can be used.

As the resin of the paste, acrylic acid ester (acrylic resin), ethyl cellulose, polyethylene glycol derivative, nitrocellulose, polymethylenestyrene, polyethylene carbonate, methacrylic acid ester and the like can be used. In particular, acrylic acid ester and ethyl cellulose are preferable because they have good thermal decomposability.

As the solvent of the paste, α-terpionel, pine oil, N, N'-dimethylformamide (DMF), higher alcohol, γ-butyrolactone (γ-BL), tetralin, butylcarbitol acetate, ethyl acetate, isoamyl acetate, etc. Diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, benzyl alcohol, toluene, 3-methoxy-3-methylbutanol, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, tripropylene Glycol monomethyl ether, tripropylene glycol monobutyl ether, propylene carbonate, N-methyl-2-pyrrolidone and the like can be used. In particular, α-turpioner is preferable because it has high viscosity and good solubility of resins and the like.

The firing temperature is preferably within the range of the softening point ± 100 ° C., particularly the softening point ± 50 ° C. of the adhesive. Specifically, the firing temperature is preferably in the range of, for example, 500 ° C to 800 ° C, particularly 600 ° C to 750 ° C. If the firing temperature is too low, the softening flow becomes insufficient and the adhesive strength tends to be inferior. On the other hand, if the firing temperature is too high, the fluidity tends to be excessive and joining tends to be difficult. Further, when the adhesive contains crystalline glass, crystal transition (for example, crystal transition from β-quartz solid solution to β-spojumen solid solution) may occur and the adhesive layer 21 may be highly expanded. The adhesive may be fired by heating using a heating furnace or by using a laser.

The average particle size D ₅₀ of the adhesive is preferably 15 μm or less, 0.5 to 10 μm, and particularly preferably 0.7 to 5 μm. If the particle size of the average particle diameter D ₅₀ is too large, the adhesive layer 21 obtained after firing may have too many pores and the bonding strength may decrease. Here, "average particle size D ₅₀ " refers to a value measured by a laser diffractometer, and the cumulative amount is accumulated from the smaller particle in the volume-based cumulative particle size distribution curve measured by the laser diffractometer. It represents a particle size of 50%.

(Third embodiment)
FIG. 10 illustrates the electronic device 1 according to the third embodiment of the present invention. In the third embodiment, the protective cap 4 is composed of a single member having no joint between the frame portion 6 and the lid portion 7, which is different from the first and second embodiments. The frame portion 6 of the protective cap 4 composed of a single member is directly welded to the base material 3 by the welding portion 9.

The present invention is not limited to the configuration of the above embodiment, and is not limited to the above-mentioned action and effect. The present invention can be modified in various ways without departing from the gist of the present invention.

In the above embodiment, after joining the frame portion 6 and the base material 3, the lid portion 7 may be joined to the frame portion 6. In this case, the electronic component 2 may be mounted on the base material 3 after the frame portion 6 and the base material 3 are joined, and then the lid portion 7 may be joined to the frame portion 6. However, in consideration of workability, it is preferable to mount the electronic component 2 on the base material 3 before joining the frame portion 6 and the base material 3.

In the above embodiment, a reflective film may be formed on the inner peripheral surface of the frame portion 6 in order to improve the extraction efficiency of ultraviolet rays.

1 Electronic device 2 Electronic component 3 Base material 4 Protective cap 5 Joint part 6 Frame part 7 Lid part 8 Joint part 9 Welding part 10 Welding part

Claims (8)

1. An electronic device comprising an electronic component, a base material on which the electronic component is mounted, and a protective cap bonded to the base material so that the electronic component is housed therein.
   The protective cap includes a frame portion made of a first transparent inorganic material and a lid portion made of a second transparent inorganic material that covers one end opening of the frame portion.
   An electronic device in which the frame portion and the base material are directly welded.
2. The electronic device according to claim 1, wherein the frame portion and the lid portion are directly welded.
3. The electronic device according to claim 1 or 2, wherein the first transparent inorganic material is quartz glass.
4. The electronic device according to any one of claims 1 to 3, wherein the second transparent inorganic material is a glass material having a softening point of 1000 ° C. or lower.
5. The electronic device according to any one of claims 1 to 3, wherein the second transparent inorganic material is quartz glass.
6. The electronic device according to any one of claims 1 to 5, wherein the electronic component is an ultraviolet LED.
7. A method of manufacturing an electronic device including an electronic component, a base material on which the electronic component is mounted, and a protective cap bonded to the base material so that the electronic component is housed inside.
   The protective cap includes a frame portion made of a first transparent inorganic material and a lid portion made of a second transparent inorganic material that covers one end opening of the frame portion.
   A bonding step is provided in which the frame portion and the base material are directly welded by irradiating the contact portion between the frame portion and the base material with a laser in a state where the frame portion and the base material are in contact with each other. A method of manufacturing an electronic device, characterized in that it is used.
8. Further provided with a joining step of directly welding the frame portion and the lid portion by irradiating the contact portion between the frame portion and the lid portion with a laser in a state where the frame portion and the lid portion are in contact with each other. The method for manufacturing an electronic device according to claim 7.

Images