Silica component and LED device

Abstract

The present application has a main body portion including a silica glass, the main body portion having an other member joining portion that joins with another member, at the other member joining portion, a base layer, an intermediate layer, and a surface layer including Au are provided in this order from the main body portion side, the base layer has a void ratio in a range of 5% or more and 10% or less, the intermediate layer has a void ratio in a range of 4% or more and 5% or less, and the base layer has a thickness in a range of 20 nm or more and 100 nm or less, and the intermediate layer has a thickness in a range of 100 nm or more and 200 nm or less.

Description

TECHNICAL FIELD

[0001] The present application relates to a silica member and an LED device, and particularly relates to a silica member suitable for a cover, a lens, or the like of an ultraviolet LED (Light Emitting Diode), and an LED device using the same. BACKGROUND

[0002] With respect to ultraviolet sterilization, a mercury lamp has been widely used, but due to the entry into force of the Minamata Convention on Mercury, the manufacture, import, and export of mercury products are restricted after 2020. Therefore, as a replacement light source after the life of the currently used mercury lamp is exhausted, an ultraviolet LED, particularly a deep ultraviolet LED having a wavelength of 280 nm or less, is attracting attention. The LED is, for example, placed in a frame body and used in airtight with a glass lens or the like.

[0003] For example, in Patent Literature 1, a light emitting module in which a packaging substrate composed of aluminum nitride or the like and a window member composed of quartz glass are joined by a sealing portion composed of a low-melting-point metal material such as AuSn (gold-tin), AgSn (silver-tin), or the like is described. On the joint portion of the window member with respect to the packaging substrate, a multilayer film in which Ti (titanium), Cu (copper), Ni (nickel), and Au (gold) are sequentially stacked from the joint portion side is formed, and the joint portion of the packaging substrate and the window member is subjected to a metallization treatment.

[0004] In addition, for example, in Patent Literature 2, an LED device in which a main body portion composed of silica glass having a lens portion and a flange portion and a frame body composed of aluminum nitride are fusion-bonded by AuSn solder is described. In the flange portion as a joint portion with the frame body, a Cu layer having a thickness of 0.5 μm is formed as a base layer by wet plating, and on the surface of the base layer, an Au layer having a thickness of 0.5 μm is formed by wet plating, and a frame body metallization layer in which a Ni layer and an Au layer are sequentially formed is formed on the joint portion with the main body portion of the frame body.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Publication No. 2017-59716

[0008] Patent Literature 2: Japanese Patent Application Publication No. 2019-46826 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] However, in the related art, in the joint portion of the silica glass member and the ceramic member, a metal such as Ti, Cu, Ni, Au, or the like is densely deposited on the surface of the silica glass member, and thus, when the silica glass member is joined to the ceramic member, the thermal expansion rates of the silica glass and the metal are different, and thus, there is a problem in that a stress caused by heat is generated. Thus, the silica glass is subjected to a load, and there is a possibility that the member is broken.

[0011] The present application has been achieved based on such a problem, and an object thereof is to provide a silica member capable of being joined well while suppressing breakage and an LED device using the silica member.

[0012] Technical means for solving the problem

[0013] The silica member of the present application includes a main body portion including a silica glass, the main body portion having an other member joint portion to be joined to another member, a base layer, an intermediate layer, and a surface layer including Au being provided in this order from the main body portion side in the other member joint portion, the base layer having a porosity in a range of 5% or more and 10% or less, the intermediate layer having a porosity in a range of 4% or more and 5% or less, and the base layer having a thickness in a range of 20 nm or more and 100 nm or less, and the intermediate layer having a thickness in a range of 100 nm or more and 200 nm or less.

[0014] The LED device of the present application includes an LED, a base member supporting the LED, and the silica member of the present application joined to the base member in a manner of covering the LED, the base member having a silica member joint portion to be joined to the silica member, a metallized layer being formed in the silica member joint portion, the metallized layer having a first layer including Au on a surface, and the silica member joint portion of the base member and the other member joint portion of the silica member being joined by a solder layer including an AuSn solder.

[0015] Effects of the invention

[0016] The silica member of the present application includes a main body portion including a silica glass, the main body portion having an other member joint portion to be joined to another member, a base layer, an intermediate layer, and a surface layer including Au being provided in this order from the main body portion side in the other member joint portion, the base layer having a porosity in a range of 5% or more and 10% or less, the intermediate layer having a porosity in a range of 4% or more and 5% or less, and the base layer having a thickness in a range of 20 nm or more and 100 nm or less, and the intermediate layer having a thickness in a range of 100 nm or more and 200 nm or less.

[0017] Further, if the thickness of the base layer is set to 20 nm or more and 100 nm or less, internal stress can be relaxed while ensuring adhesion. Furthermore, if the thickness of the intermediate layer is 100 nm or more and 200 nm or less, the effect of the barrier layer for preventing diffusion of Sn atoms of the solder can be maintained, and internal stress can be relaxed.

[0018] Further, if the porosity of the base layer is made greater than the porosity of the intermediate layer, the adhesion of the base layer to the intermediate layer can be improved while reducing the stress burden, stress can be more effectively relaxed, and air tightness can be ensured.

[0019] Furthermore, if the porosity of the surface layer is set to 0.1% or more and 0.5% or less, and the thickness of the surface layer is set to 150 nm or more and 500 nm or less, internal stress can be suppressed from becoming large, and the main body portion and other components can be firmly joined using the solder.

[0020] Further, if at least one of a Cr (chromium) layer and a Ti layer is included in the base layer, adhesion to the main body portion including the silica glass can be improved. Further, if at least one of a Ni layer and a Ti layer is included in the intermediate layer, Sn atoms contained in the solder can be prevented from intruding into the base layer, and the adhesion of the other component joining portion to the base layer can be prevented from deteriorating.

[0021] Further, the average particle diameter of the base layer based on the linear intercept method is preferably set to a range of 40 nm or more and 80 nm or less, the average particle diameter of the intermediate layer based on the linear intercept method is preferably set to a range of 50 nm or more and 70 nm or less, and the average particle diameter of the surface layer based on the linear intercept method is preferably set to a range of 50 nm or more and 70 nm or less, whereby a moderate void can be obtained, the Young's modulus can be reduced to a prescribed range, each layer can be easily deformed, and internal stress generated at the time of film formation can be relaxed.

[0022] According to the LED device of the present application, a silica component of the present application is used, a metallized layer having a first layer containing Au is formed on the surface of the silica component joining portion of the base component, and the silica component joining portion of the base component and the other component joining portion of the silica component are joined using a solder layer containing AuSn solder, and thus can be joined well. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a view showing the structure of an LED lens which is a silica component according to a first embodiment of the present application.

[0024] Figure 2 is a sectional view showing the structure of an LED device using the LED lens shown in Figure 1 is a sectional view showing the structure of an LED device using the LED lens shown in

[0025] Figure 3 FIG. 2 is a diagram showing a structure of a cover for an LED as a silicon dioxide member according to a second embodiment of the present application.

[0026] Figure 4 FIG. 4 is an image diagram showing a particle state of a base layer in Example 1.

[0027] Figure 5 FIG. 5 is an image diagram showing a particle state of an intermediate layer in Example 1.

[0028] Figure 6 FIG. 6 is an image diagram showing a particle state of a surface layer in Example 1.

[0029] Symbol explanation

[0030] 10 lens for LED

[0031] 11 main body

[0032] 11A lens portion

[0033] 11B flange portion

[0034] 11C other member joining portion

[0035] 12 base layer

[0036] 13 intermediate layer

[0037] 14 surface layer

[0038] 20 LED device

[0039] 21 LED

[0040] 22 basic member

[0041] 23 recess

[0042] 24 step portion

[0043] 25 solder layer

[0044] 26 metallization layer

[0045] 30 cover for LED

[0046] 31 main body

[0047] 31A cover portion

[0048] 31B flange portion

[0049] 31C other member joining portion DETAILED DESCRIPTION

[0050] Embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0051] (First Embodiment)

[0052] Figure 1 A structure of an LED lens 10 as a silica member according to the first embodiment is shown, (A) shows a cross-sectional structure, and (B) shows a structure viewed from the lower side. Figure 2 A cross-sectional structure of an LED device 20 using the LED lens 10 is shown, (A) shows an overall structure, and (B) shows a portion of the dotted line shown in (A) in an enlarged manner.

[0053] The LED lens 10 has a main body 11 including silica glass. The main body 11 has, for example, a lens portion 11A having a semispherical shape and a flange portion 11B provided at a planar side peripheral portion of the lens portion 11A. The LED lens 10 is used, for example, for an LED device 20.

[0054] The LED device 20 has, for example, the LED lens 10, an LED 21, and a base member 22 supporting the LED 21, and the LED lens 10 is disposed with respect to the base member 22 so as to cover the LED 21. A recess 23 in which the LED 21 is disposed is provided in the base member 22, and a step portion 24 for disposing the LED lens 10 is provided in an upper portion of the recess 23. The LED lens 10 is disposed so that the flange portion 11B abuts against the step portion 24, and a bottom surface of the flange portion 11B is joined to an upper surface of the step portion 24. That is, the bottom surface of the flange portion 11B in the LED lens 10 is a member joining portion 11C that is joined to the base member 22 as another member, and the upper surface of the step portion 24 in the base member 22 is a silica member joining portion that is joined to the LED lens 10 as a silica member.

[0055] The bottom surface of the flange portion 11B of the LED lens 10 and the upper surface of the step portion 24 of the base member 22 are joined, for example, by fusion bonding through a solder layer 25. This is for sealing with high airtightness. As a material of the solder layer 25, AuSn solder is preferable. In addition, in order to improve wettability with solder, a metallized layer 26 is preferably formed on the upper surface of the step portion 24. The metallized layer 26 preferably has, for example, a first layer including Au on a surface, and preferably has a Ni layer between the first layer and the step portion 24.

[0056] On the bottom surface of the flange portion 11B of the lens 10 for an LED, that is, the other member joining portion 11C, a base layer 12, an intermediate layer 13, and a surface layer 14 containing Au are provided in this order from the main body portion 11 side. This is because silica glass is difficult to wet with solder, and thus the surface is metallized to make the compatibility with solder good. In particular, Au reacts with AuSn solder to alloy and form intermetallic compounds such as Au5Sn, AuSn, AuSn2, AuSn4, and the like, and thus by providing the surface layer 14 with Au, the compatibility with solder can be improved. Note that in the case where the surface layer 14 is provided with Au, the surface layer 14 can be provided with a layer of another metal such as Cr, Ti, or the like in addition to Au. Figure 1 (B) in which the region provided with the base layer 12, the intermediate layer 13, and the surface layer 14 is indicated by a dot.

[0057] The base layer 12 serves to improve the adhesion to silica glass and suppress peeling. The base layer 12 can be composed of a single layer of a metal, or can be composed of a plurality of layers stacked. The base layer 12 preferably includes at least one of a Cr layer and a Ti layer, and is preferably composed of a Cr layer, a Ti layer, or a plurality of layers in which a Cr layer and a Ti layer are stacked. This is because Cr and Ti can achieve good adhesion to silica glass.

[0058] The intermediate layer 13 serves to suppress the invasion of Sn atoms contained in the solder layer 25 into the base layer 12 and suppress the deterioration of the adhesion of the other member joining portion 11C to the base layer 12. The intermediate layer 13 is composed of a metal, and can be composed of a single layer or a plurality of layers stacked. The intermediate layer 13 preferably includes at least one of a Ni layer and a Ti layer, and is preferably composed of a Ni layer, a Ti layer, or a plurality of layers in which a Ni layer and a Ti layer are stacked. This is because Ni and Ti have a high effect of suppressing the invasion of Sn atoms into the base layer 12.

[0059] The porosity of the base layer 12 is in the range of 5% or more and 10% or less, and the porosity of the intermediate layer 13 is preferably in the range of 4% or more and 5% or less. This is to reduce the internal stress generated at the time of joining the main body portion 11 to the base member 22 due to the difference in thermal expansion rate between silica glass and metal by controlling the porosity (film density). If the porosity of the base layer 12 is less than 5%, the stress cannot be sufficiently relaxed, and the surface of the main body portion 11 is easily damaged. On the other hand, if the porosity of the base layer 12 exceeds 10%, the adhesion of the main body portion 11 to the base member 22 is insufficient, and peeling occurs at the time of joining, and thus the air tightness cannot be ensured, and good joining is difficult to achieve.

[0060] In addition, if the void ratio of the intermediate layer 13 is less than 4%, stress cannot be sufficiently relaxed, and this can cause damage to the main body portion 11. If the void ratio of the intermediate layer 13 exceeds 5%, the interface between the base layer 12 and the intermediate layer 13 can sometimes peel off when the main body portion 11 is joined to the base member 22, because the adhesion between the base layer 12 and the intermediate layer 13 is not sufficient. Furthermore, it is generally considered that Sn atoms of the solder easily diffuse into the intermediate layer 13 and the base layer 12 at the time of soldering, and this accelerates the deterioration of the joining interface between the other member joining portion 11C and the base layer 12, and the life of the LED device 20 becomes short.

[0061] The thickness of the base layer 12 is preferably in the range of 20 nm or more and 100 nm or less. This is because, if the thickness of the base layer 12 is less than 20 nm, the void ratio is large, and thus the base layer 12 easily peels off when joined to the base member 22 because of insufficient adhesion to the other member joining portion 11C. In addition, if the thickness of the base layer 12 exceeds 100 nm, internal stress becomes large, and the main body portion 11 easily breaks. The thickness of the intermediate layer 13 is preferably in the range of 100 nm or more and 200 nm or less. This is because, if the thickness of the intermediate layer 13 is less than 100 nm, the effect as a barrier layer for preventing the diffusion of Sn atoms of the solder decreases, and if it exceeds 200 nm, internal stress becomes large, and the main body portion 11 easily breaks. In addition, if the thickness of the intermediate layer 13 exceeds 200 nm, the intermediate layer 13 shrinks at the time of cooling after film formation, and cracks easily occur.

[0062] The void ratio of the base layer 12 is preferably larger than the void ratio of the intermediate layer 13. This is because, by increasing the void ratio of the base layer 12, the effect of reducing the stress burden on the main body portion 11 can be obtained, and the intermediate layer 13 can reduce the stress burden while increasing the adhesion between the base layer 12 and the intermediate layer 13, and thus stress can be relaxed more effectively, and air tightness can be ensured.

[0063] The void ratio of the surface layer 14 is preferably in the range of 0.1% or more and 0.5% or less. This is because the metallized layer 26 formed at the step portion 24 and the surface layer 14 can be joined more firmly by the solder layer 25. Note that the void ratios of the base layer 12, the intermediate layer 13, and the surface layer 14 can be controlled, for example, by adjusting the pressure or the input power at the time of film formation by a vacuum evaporation method or a sputtering method.

[0064] The thickness of the surface layer 14 is preferably in a range of 150 nm or more and 500 nm or less. By setting the thickness of the surface layer 14 to 150 nm or more, it is possible to prevent Sn atoms of the solder from diffusing into the surface layer 14 to cause the entire surface layer 14 to be alloyed at the time of soldering, thereby reducing the joining strength of the surface layer 14. As a result, it is possible to improve the joining strength of the main body portion 11 to the base member 22, prevent peeling, and extend the life of the LED device 20. In addition, by making the thickness of the surface layer 14 500 nm or less, it is possible to reduce internal stress and prevent breakage from occurring. Thus, it is possible to prevent the diffusion of Sn atoms due to the breakage portion, the increase in the melting point due to a decrease in the concentration of the solder, and the resulting difficulty in melting the solder and joining. Note that the thickness of each layer can be obtained, for example, by observing the cross-sectional structure of each layer using an FE-SEM (field emission scanning electron microscope) device and measuring it.

[0065] In addition, the porosity in the present application refers to the porosity in two dimensions obtained by photographing the upper surface of the base layer 12, the intermediate layer 13, or the surface layer 14 and dividing the total area of the void portion by the entire area from the obtained image. Specifically, for example, the upper surface of the base layer 12, the intermediate layer 13, or the surface layer 14 is photographed using an FE-SEM device (S-4800) manufactured by Hitachi High-Technologies Corporation, and the photographed image is binarized for the void portion using OpenCV of an image processing module by a programming language Python, whereby the porosity can be calculated. At this time, the portion in which the contrast greatly changes in the image is judged to be a pore. For the upper surface of the base layer 12 or the intermediate layer 13, for example, the surface layer 14 and the intermediate layer 13 or the surface layer 14 are removed by etching or the like, and the base layer 12 and the intermediate layer 13 are exposed to the surface to be photographed.

[0066] The average particle diameter of the base layer 12 measured based on the linear intercept method is preferably in a range of 40 nm or more and 80 nm or less, the average particle diameter of the intermediate layer 13 measured based on the linear intercept method is preferably in a range of 50 nm or more and 70 nm or less, and the average particle diameter of the surface layer 14 measured based on the linear intercept method is preferably in a range of 50 nm or more and 70 nm or less. By setting the average particle diameter to be in this range, there are moderate voids in each layer, it is possible to reduce the Young's modulus to a prescribed range, and thus each layer is easily deformed, and it is possible to relieve internal stress generated at the time of film formation.

[0067] In addition, the Young's modulus of the base layer 12 is preferably in a range of 30% or more and 70% or less of the Young's modulus of the material block constituting the base layer 12, the Young's modulus of the intermediate layer 13 is preferably in a range of 40% or more and 80% or less of the Young's modulus of the material block constituting the intermediate layer 13, and the Young's modulus of the surface layer 14 is preferably in a range of 20 GPa or more and 60 GPa or less.

[0068] Note that, in the present application, the average particle diameter measured based on the linear intercept method refers to the average particle diameter observed on the upper surface of the base layer 12, the intermediate layer 13, or the surface layer 14, measured based on the linear intercept method of ISO 13383-1:2012. Specifically, for example, the upper surface of the base layer 12, the intermediate layer 13, or the surface layer 14 is imaged by an FE-SEM device (S-4800) manufactured by Hitachi High-Technologies Corporation, 10 straight lines are drawn on the imaged image, the particles on the straight lines are counted, and the particle diameter is calculated by dividing the length of the straight line by the number. For the upper surface of the base layer 12 or the intermediate layer 13, the surface layer 14 and the intermediate layer 13 or the surface layer 14 are removed by etching or the like, and the base layer 12 and the intermediate layer 13 are exposed to the surface, and the observation is performed.

[0069] The Young's modulus of the base layer 12, the intermediate layer 13, or the surface layer 14 is measured, for example, using a surface acoustic wave method (in accordance with DIN (Deutsches Institut fur Normung) specification 50992-1) that measures the surface acoustic wave excited by irradiating a test sample with a pulsed laser (wavelength 337 nm) using a piezoelectric element, and calculates the Young's modulus from a dispersion curve. For the base layer 12 or the intermediate layer 13, the surface layer 14 and the intermediate layer 13 or the surface layer 14 are removed by etching or the like, and the base layer 12 and the intermediate layer 13 are exposed to the surface, and the measurement is performed.

[0070] In addition, in the case where the base layer 12 or the intermediate layer 13 is composed of a plurality of layers, the Young's modulus of the base layer 12 or the intermediate layer 13 is determined for each layer that constitutes the base layer 12 or the intermediate layer 13. That is, if it is the base layer 12, the Young's modulus of each layer that constitutes the base layer 12 is preferably in the range of 30% or more and 70% or less of the Young's modulus of the bulk material that constitutes the layer, and if it is the intermediate layer 13, the Young's modulus of each layer that constitutes the intermediate layer 13 is preferably in the range of 40% or more and 80% or less of the Young's modulus of the bulk material that constitutes the layer.

[0071] The lens 10 for an LED can be manufactured, for example, as follows. First, the main body portion 11 is formed from silica glass. For example, the silica powder is shaped by a gel casting method, and sintered to form the main body portion 11. Next, the base layer 12, the intermediate layer 13, and the surface layer 14 are sequentially stacked on at least a part of the bottom surface of the flange portion 11B, that is, the other member joining portion 11C. In the film formation of the base layer 12, the intermediate layer 13, and the surface layer 14, for example, a vacuum evaporation method or a sputtering method is used, the pressure is appropriately adjusted in the range of, for example, 0.5 Pa to 3.0 Pa, and the input power is appropriately adjusted in the range of, for example, 50 W to 200 W, whereby the void ratio of each layer is adjusted.

[0072] Further, the LED lens 10 is joined to the base member 22 by a solder layer 25, for example. For example, a strip-shaped solder is arranged on the step portion 24 of the base member 22 on which the other member joining portion 11C of the other member on which the base layer 12, the intermediate layer 13, and the surface layer 14 are formed is abutted, and the LED lens 10 is arranged thereon, and it is heated and melted in an oxygen-free atmosphere to be fusion-bonded.

[0073] Thus, according to the present embodiment, the base layer 12, the intermediate layer 13, and the surface layer 14 including Au are provided at the other member joining portion 11C of the main body 11 composed of silica glass, the void ratio of the base layer 12 is set to 5% or more and 10% or less, and the void ratio of the intermediate layer 13 is set to 4% or more and 5% or less, so that stress generated at the joining of the main body 11 and the base member 22 can be moderated, breakage of the main body 11 can be suppressed, and the main body 11 and the base member 22 can be firmly joined to ensure airtightness.

[0074] Further, if the thickness of the base layer 12 is set to 20 nm or more and 100 nm or less, internal stress can be moderated while ensuring adhesion. Furthermore, if the thickness of the intermediate layer 13 is set to 100 nm or more and 200 nm or less, the effect as a barrier layer for preventing diffusion of Sn atoms of the solder can be maintained while internal stress can be moderated.

[0075] Further, if the void ratio of the base layer 12 is made larger than the void ratio of the intermediate layer 13, the adhesion of the base layer 12 and the intermediate layer 13 can be improved while reducing the burden of stress, stress can be more effectively moderated, and airtightness can be ensured.

[0076] Furthermore, if the void ratio of the surface layer 14 is set to 0.1% or more and 0.5% or less and the thickness of the surface layer 14 is set to 150 nm or more and 500 nm or less, internal stress can be suppressed from becoming large, and the main body 11 and the base member 22 can be more firmly joined by the solder.

[0077] Further, if at least one of a Cr layer and a Ti layer is included in the base layer 12, adhesion to the main body 11 including silica glass can be improved. Further, if the intermediate layer 13 includes at least one of a Ni layer and a Ti layer, Sn atoms contained in the solder can be suppressed from intruding into the base layer 12, and adhesion of the other member joining portion 11C and the base layer 12 can be suppressed from deteriorating.

[0078] Further, the average particle diameter of the base layer 12 measured based on the linear intercept method is preferably set to a range of 40 nm or more and 80 nm or less, the average particle diameter of the intermediate layer 13 measured based on the linear intercept method is preferably set to a range of 50 nm or more and 70 nm or less, and the average particle diameter of the surface layer 14 measured based on the linear intercept method is preferably set to a range of 50 nm or more and 70 nm or less, whereby a moderate void can be obtained, the Young's modulus can be reduced to a prescribed range, and thus each layer is easily deformed, and internal stress generated at the time of film formation can be relaxed.

[0079] (Second Embodiment)

[0080] Figure 3 The structure of the silicon dioxide member, i.e., the LED cover 30 according to the second embodiment is shown, (A) shows a cross-sectional structure, and (B) shows a structure viewed from the lower side. The LED cover 30 has the same structure as that of the LED lens 10 described in the first embodiment, except that the shape of the main body portion 31 is different from that of the LED lens 10 described in the first embodiment. Therefore, the same reference numerals are assigned to the same components, and the same reference numerals with the tens digit changed to "3" are assigned to the corresponding components, and detailed description thereof is omitted.

[0081] The main body portion 31 contains silicon dioxide glass, and for example, has a cover portion 31A having a one-end-sealed cylindrical shape, and a flange portion 31B provided at the opening end portion of the cover portion 31A. The flange portion 31B corresponds to the flange portion 1 IB in the first embodiment, and is disposed in the step portion 24 of the base member 22 as in the first embodiment, and the bottom surface of the flange portion 31B is engaged with the upper surface of the step portion 24 (see FIG. 1). Figure 2 That is, in the LED cover 30, the bottom surface of the flange portion 31B becomes the other member engaging portion 31C which is engaged with the base member 22 as the other member. In the bottom surface of the flange portion 31B, i.e., the other member engaging portion 31C of the LED cover 30, the base layer 12, the intermediate layer 13, and the surface layer 14 containing Au are sequentially provided from the main body portion 31 side as in the first embodiment. Figure 3 In (B) of FIG. 1, the regions where the base layer 12, the intermediate layer 13, and the surface layer 14 are provided are shown by dots.

[0082] The LED cover 30 can be manufactured and used as in the LED lens 10 described in the first embodiment. In addition, the same effects can be obtained.

[0083] Example

[0084] (Example 1)

[0085] The LED lens 10 shown in FIG. 1 was produced. First, a silicon dioxide powder was formed by a gel casting method and subjected to firing, and a lens having a lens diameter of 3 mm and a thickness of 0.5 mm was produced. Figure 1 The base layer 12, the intermediate layer 13, and the surface layer 14 were sequentially formed on the flange portion 31B of the main body portion 31 of the LED cover 30. A main body 11 of silica glass having a lens portion 11A of a semispherical shape with a lens height of 1.5 mm and a flange portion 11B of a quadrangular shape with a flange diameter of 3.5 x 3.5 mm and a flange thickness of 0.5 mm. Next, on the bottom surface of the flange portion 11B, a Cr layer with a thickness of 50 nm as a base layer 12, a Ni layer with a thickness of 150 nm as an intermediate layer 13, and an Au layer with a thickness of 300 nm as a surface layer 14 were sequentially formed. The formation of the base layer 12, the intermediate layer 13, and the surface layer 14 was performed by a sputtering device with a pressure condition appropriately set to 1 Pa to 3 Pa and an input power appropriately set in the range of 120 W to 160 W. Next, a photosensitive resist was applied on the base layer 12, the intermediate layer 13, and the surface layer 14 formed on the bottom surface of the flange portion 11B, and a frame-shaped pattern with an outer diameter of 3.3 mm x 3.3 mm and an inner diameter of 2.7 mm x 2.7 mm was formed by photolithography.

[0086] For the lens 10 for an LED thus produced, the void fractions of the base layer 12, the intermediate layer 13, and the surface layer 14 were measured. The FE-SEM device (S-4800) manufactured by Hitachi High-Technologies Corporation was used to take images of the surfaces of the respective layers at a pressure of 5 kV and a magnification of 100,000 times. For the void fraction (%), the images taken were subjected to 2-value processing of the void portions using the OpenCV of the image processing module by the programming language Python, and the total area of the void portions was divided by the entire area and multiplied by 100 to calculate. At this time, the portions with a large change in contrast were judged as pores. In addition, when the surface of the intermediate layer 13 was taken, the surface layer 14 was etched under the conditions that the chemical solution was AURUM-314 manufactured by Kanto Chemical Co., Inc., the temperature was room temperature, and the time was 5 minutes, so that the intermediate layer 13 became the topmost surface, and then the surface was taken. When the surface of the base layer 12 was taken, after the surface layer 14 was etched and removed as described above, the intermediate layer 13 was etched under the conditions that the chemical solution was mixed acid Cu-02 manufactured by Kanto Chemical Co., Inc., the temperature was room temperature, and the time was 10 minutes, so that the base layer 12 became the topmost surface, and then the surface was taken.

[0087] Figure 4 (A) SEM image, (B) processed image, and (C) image of the void portion of the base layer 12 are shown. Figure 5 (A) SEM image, (B) processed image, and (C) image of the void portion of the intermediate layer 13 are shown. Figure 6 (A) SEM image, (B) processed image, and (C) image of the void portion of the surface layer 14 are shown. As shown in Figures 4 to 6 It was confirmed that the base layer 12, the intermediate layer 13, and the surface layer 14 respectively had voids. In terms of the void fraction, the base layer 12 was 9.5%, the intermediate layer 13 was 4.6%, and the surface layer 14 was 0.2%.

[0088] In addition, the average particle sizes of the base layer 12, intermediate layer 13, and surface layer 14 were measured using the linear cutoff method. The measurements were performed using a FE-SEM apparatus (S-4800) manufactured by Hitachi High Technology Co., Ltd., and images of the upper surface of each layer were taken. The results were calculated according to ISO 13383-1:2012. The results showed that the average particle sizes measured using the linear cutoff method were 63 nm for the base layer 12, 58 nm for the intermediate layer 13, and 62 nm for the surface layer 14.

[0089] Furthermore, the Young's modulus of the substrate layer 12, intermediate layer 13, and surface layer 14 was measured. The measurement was performed using the surface elastic wave method (according to DIN (German Standards Institute) standard 50992-1). The surface elastic wave method uses a piezoelectric element to measure the surface elastic waves excited by irradiating the upper surface of each layer with a pulsed laser (wavelength 337 nm), and the Young's modulus is calculated based on the dispersion curve. The results show that the Young's modulus of the substrate layer 12 is 50% of the Young's modulus of the Cr bulk material constituting the substrate layer 12; the Young's modulus of the intermediate layer 13 is 60% of the Young's modulus of the Ni bulk material constituting the intermediate layer 13; and the Young's modulus of the surface layer 14 is 40 GPa.

[0090] Next, prepare as follows Figure 2 The basic component 22 is made of aluminum nitride. A metallization layer 26 is formed on the step portion 24 of the basic component 22. The metallization layer 26 has a first layer containing Au on its surface and a Ni layer between the first layer and the step portion 24. Then, a frame-shaped AuSn solder with an outer diameter of 3.2 mm × 3.2 mm, an inner diameter of 2.8 mm × 2.8 mm, and a thickness of 20 μm is inserted between the flange portion 11B of the main body portion 11 and the step portion 24 of the basic component 22. The soldering is carried out under pressure conditions of 300°C, 0.5 MPa, and 30 seconds to obtain the LED device 20. Ten LED devices 20 were manufactured, and no damage was observed in any of the ten LEDs using the lens 10. In addition, to confirm the airtightness of the LED device 20, i.e., the tightness between the main body portion 11 and the basic component 22, a Fluorinert test (usually a coarse leak test) was performed. The results confirmed that all ten devices remained airtight without any leaks.

[0091] It should be noted that the Fluorinert test is based on the airtightness test method specified in the MIL standard (MIL-STD-883). A Freon-based liquid called Fluorinert (FLORINERT: a trademark of Slim Corporation of the United States) with a high boiling point and low viscosity is stored in a container. The sample is immersed in Fluorinert heated to 125°C for 1 minute, and the presence of bubbles generated from the sample is observed to determine whether there is any leakage. The airtightness is thus evaluated.

[0092] (Comparative Example 1)

[0093] After the main body portion 11 was produced in the same manner as in Example 1, a Cr layer having a porosity of 0.1% as the base layer 12, a Ni layer having a porosity of 0.1% as the intermediate layer 13, and an Au layer having a porosity of 0.05% as the surface layer 14 were sequentially formed on the bottom surface of the flange portion 1 IB by a vacuum evaporation device, and the same as in Example 1 was molded into a frame shape. The thickness of each layer was the same as in Example 1, and the porosities of the layers were measured in the same manner as in Example 1. Then, the same operations as in Example 1 were performed, and the produced LED lens 10 and the aluminum nitride base member 22 were joined to produce the LED device 20. Ten LED devices 20 were produced, and as a result, cracks were observed on the outer diameter of the flange portion 1 IB in eight of the ten, and breakage was observed.

[0094] (Comparative Example 2)

[0095] After the main body portion 11 was produced in the same manner as in Example 1, a Cr layer as the base layer 12, a Ni layer as the intermediate layer 13, and an Au layer as the surface layer 14 were sequentially formed on the bottom surface of the flange portion 1 IB by a sputtering device in the same thickness as in Example 1, and the same as in Example 1 was molded into a frame shape. At this time, the porosities of the layers were increased by increasing the pressure of the sputtering device and decreasing the output. The porosities of the layers were measured in the same manner as in Example 1, and as a result, the base layer 12 was 25%, the intermediate layer 13 was 25%, and the surface layer 14 was 5%. Then, the same operations as in Example 1 were performed, and the produced LED lens 10 and the aluminum nitride base member 22 were joined to produce the LED device 20. Ten LED devices 20 were produced, and as a result, breakage was not observed in all of the ten LED lenses 10. In addition, the air tightness of the LED device 20, that is, the adhesion of the main body portion 11 to the base member 22 was confirmed by the Fluorinert test, and as a result, leakage was observed in six of the ten. When the LED device 20 in which leakage was observed was pulled by hand, the LED lens 10 and the base member 22 were easily peeled apart. In addition, a use test was performed on the remaining four LED devices 20, and as a result, the LED lens 10 was peeled apart from the base member 22 during use. That is, the joint state was poor.

[0096] (Comparison between Example 1 and Comparative Examples 1 and 2)

[0097] As is clear from the results of Example 1, Comparative Example 1, and Comparative Example 2, if the porosities of the base layer 12 and the intermediate layer 13 are small, the stress cannot be sufficiently relaxed, and the LED lens 10 can be broken. In addition, it is clear that if the porosities of the base layer 12 and the intermediate layer 13 are large, the LED lens 10 and the base member 22 cannot be joined in good condition with high air tightness.

[0098] (Comparative Example 3)

[0099] The base portion 11 was produced in the same manner as in Example 1, and the base layer 12, the intermediate layer 13, and the surface layer 14 were formed on the bottom surface of the flange portion 1 IB to form a frame-shaped pattern. At this time, the thickness of the base layer 12 was set to 300 nm, the thickness of the intermediate layer 13 was set to 500 nm, and the thickness of the surface layer 14 was set to 800 nm. The void ratio of each layer was the same as in Example 1. Next, the LED lens 10 produced and the aluminum nitride base member 22 were joined in the same manner as in Example 1 to produce the LED device 20. Ten LED devices 20 were produced, and as a result, cracks were observed from the outer diameter of the flange portion 1 IB in seven of the ten, and breakage was observed.

[0100] (Comparative Example 4)

[0101] The base portion 11 was produced in the same manner as in Example 1, and the base layer 12, the intermediate layer 13, and the surface layer 14 were formed on the bottom surface of the flange portion 1 IB to form a frame-shaped pattern. At this time, the thickness of the base layer 12 was set to 300 nm, the thickness of the intermediate layer 13 was set to 500 nm, and the thickness of the surface layer 14 was set to 800 nm. The void ratio of each layer was the same as in Example 1. Next, the LED lens 10 produced and the aluminum nitride base member 22 were joined in the same manner as in Example 1 to produce the LED device 20. Ten LED devices 20 were produced, and as a result, cracks were observed from the outer diameter of the flange portion 1 IB in seven of the ten, and breakage was observed.

[0102] (Comparison of Example 1 and Comparative Examples 3 and 4)

[0103] As is clear from the results of Example 1, Comparative Example 3, and Comparative Example 4, if the thicknesses of the base layer 12, the intermediate layer 13, and the surface layer 14 are thick, stress cannot be sufficiently relaxed, and the LED lens 10 can break. In addition, if the thicknesses of the base layer 12, the intermediate layer 13, and the surface layer 14 are thin, it is clear that the LED lens 10 and the base member 22 cannot be joined with high airtightness.

[0104] Although the present application has been described above according to each embodiment, the present application is not limited to the above-described embodiments, and various modifications can be made. For example, in the above-described embodiments, as the silica member, the LED lens 10 and the LED cover 30, which are light source members, were described, but the present application can also be applied to other light source members. In addition, the present application is not limited to light source members, and can also be applied to optical windows for optical equipment, covers for quartz resonators, and other silica members.

[0105] Moreover, in the above-described embodiments, the structure of the lens 10 for an LED and the cover 30 for an LED is specifically described, but other structures can also be adopted. For example, in the above-described embodiments and examples, the case where the outer peripheral shape of the flange portion 1 IB, 31B is square is described, but it can also be circular, or a polygon other than square. In addition, the flange portion 1 IB, 31B can also not be provided. In this case, for example, the peripheral portion of the planar portion of the lens portion 1 IA, the opening end portion of the cover portion 31A can be provided as other member joining portions 1 IC, 31C. Also, in the above-described embodiments and examples, the case where the shape of the lens portion 1 IA is hemispherical is described, but it can also be a shape other than a hemisphere (spherical surface) such as an aspherical surface, a semi-long sphere, or the like.

[0106] Furthermore, in the above-described embodiments and examples, the structure of the basic member 22 is specifically described, but other structures can also be adopted. For example, in the above-described embodiments and examples, the case where the recess portion 23 in which the LED 21 is disposed is provided on one face of the flat plate is described, but the LED 21 can also be disposed on a flat plate on which the recess portion 23 is not formed, and in addition, it can also be provided in a frame shape.

[0107] The above describes a preferred embodiment of the present application, but the present application is not limited to the above-described embodiment, and various design changes can be made within the scope recited in the claims.

[0108] This application is based on Japanese Patent Application No. 2020-217879 filed on December 25, 2020, Japanese Patent Application No. 2021-172818 filed on October 22, 2021, and Japanese Patent Application No. 2021-206469 filed on December 20, 2021, the contents of which are incorporated herein by reference in their entirety.

[0109] Industrial Applicability

[0110] The present application is particularly useful for a component for a light source or the like.

Claims

1. A silica member characterized by comprising: a main body portion including a silica glass, the main body portion has a different member joint portion which is jointed to a different member, in the different member joint portion, a base layer, an intermediate layer, and a surface layer including Au are provided in this order from the main body portion side, a porosity of the base layer is in a range of 5% or more and 10% or less, a porosity of the intermediate layer is in a range of 4% or more and 5% or less, a thickness of the base layer is in a range of 20 nm or more and 100 nm or less, and a thickness of the intermediate layer is in a range of 100 nm or more and 200 nm or less.

2. The silica member according to claim 1, characterized in that, a porosity of the base layer is larger than a porosity of the intermediate layer.

3. The silica member according to claim 1 or 2, characterized in that, a porosity of the surface layer is in a range of 0.1% or more and 0.5% or less, and a thickness of the surface layer is in a range of 150 nm or more and 500 nm or less.

4. The silica member according to any one of claims 1 to 3, characterized in that, the base layer includes at least one of a Cr layer and a Ti layer, and the intermediate layer includes at least one of a Ni layer and a Ti layer.

5. The silica member according to any one of claims 1 to 4, characterized in that, an average particle diameter of the base layer measured by a linear intercept method is in a range of 40 nm or more and 80 nm or less, an average particle diameter of the intermediate layer measured by the linear intercept method is in a range of 50 nm or more and 70 nm or less, and an average particle diameter of the surface layer measured by the linear intercept method is in a range of 50 nm or more and 70 nm or less.

6. The silica member according to any one of claims 1 to 5, characterized in that, the silica member is a lens for an LED or a cover for an LED. comprises:

7. An LED device, comprising: an LED; a basic member which supports the LED; and the silica member according to any one of claims 1 to 6 which is jointed to the basic member in a manner of covering the LED, the basic member has a silica member joint portion which is jointed to the silica member, a metallized layer is formed in the silica member joint portion, the metallized layer has a first layer including Au on a surface, the silica member joint portion of the basic member and the different member joint portion of the silica member are jointed by a solder layer including an AuSn solder. ​

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