Glass-metal feedthrough with sleeve

Abstract

The invention relates to a glass-metal feedthrough, which consists of an outer conductor or base body, a glass material or glass-ceramic material and an inner conductor, wherein the inner conductor is preferably a metal pin and is embedded in the glass or glass-ceramic material in the outer conductor, in particular the base body, characterized in that the metal pin comprises a material having a high electrical conductivity and / or a low contact resistance, and a sleeve element, which at least partially surrounds the metal pin.

Description

Technical Field

[0001] The present invention relates to a glass-metal feedthrough consisting of an outer conductor or substrate, a glass material or glass-ceramic material, and an inner conductor in the form of a metal pin. The invention further relates to the use of the glass-metal feedthrough in wearable devices, implantable medical instruments and devices, and components with such a glass-metal feedthrough. Background Art

[0002] Glass-to-metal feedthroughs are used in various application areas in electrical technology. For example, they are used to feed electrical conductors through the housings of components in electronic devices and sensor devices. In this context, such components have glass welded to different metal materials. By melting an inner conductor made of metal into a glass or glass-ceramic material surrounded by an outer conductor made of metal, a hermetically sealed feedthrough for the conductor into the housing can be provided. A very special glass-to-metal feedthrough is one in which the feedthrough itself or parts of the feedthrough come into contact with the human body. In such feedthroughs, it is important to ensure high corrosion resistance and good long-term durability of all components used. In particular, such feedthroughs should only discharge a limited amount of nickel (nickel) in order to prevent the formation of allergic reactions. This is defined in the standards for the so-called limit values ​​for the permissible amount of nickel. Reference is made to DIN EN 1811 and DIN EN 12472 in this regard.

[0003] In the case of glass-to-metal feedthroughs, Fe-Ni (iron-nickel) alloys, Fe-Ni-Co (iron-nickel-cobalt) alloys, and Fe-Ni-Cr (iron-nickel-chromium) alloys are primarily used as the material for the feedthrough conductor. The advantage of these materials is their excellent matching of the thermal expansion of the molten glass. However, all of these materials contain a large amount of Ni (nickel) in the base material. In addition, these feedthroughs have a nickel coating to protect these materials from corrosion, which again releases nickel in undesirable amounts.

[0004] To prevent the release of Ni, it is proposed in the prior art to cover the feedthrough conductor or inner conductor with a sufficiently thick gold layer to reduce nickel penetration. However, this has the disadvantage that this only provides an insufficient protection against Ni seepage, or that a very thick gold layer with a thickness of more than 2.5 μm is required to achieve this.

[0005] As an alternative to solutions with coated conductors, DE 198 42 943 A1 recommends using tantalum or, alternatively, nickel-free, rust-free ferritic stainless steel (e.g., steel according to US standard AlSi 446, a non-corroding, heat-resistant ferritic chromium steel with an aluminum addition) as the inner conductor. The coefficient of expansion of ferritic stainless steel AlSi 446 is only slightly higher than that of conventional glass. Consequently, there is a risk that upon cooling, the inner conductor will shrink more than the glass and tear apart at the junction with the glass. Furthermore, the weldability of ferritic stainless steel is also limited and is generally subject to the ingress of strong solder flux during welding. This strong solder flux can cause corrosion during subsequent operations or must be removed at great expense before use.

[0006] Another disadvantage of DE 198 42 943 C2 is that the choice of Ni-free materials is limited, since the inner conductor can only be made with a coefficient of expansion α 内 Smaller than the expansion coefficient α of glass 玻璃 Only when the feedthrough is sufficiently sealed can sufficient sealing be provided.

[0007] To ensure good electrical conductivity, metal pins are coated with nickel and / or gold in the prior art. However, the problem of Ni leaching out of such a construction arises, at least until the gold coating is complete. On the other hand, metal pins made of pure copper or brass are very difficult to embed. Another problem with coated conductors is the potential for corrosion in the presence of aqueous solutions or water. Materials such as niobium and titanium that are at least selectively coated (e.g., by a wet electroplating process) are sufficient for solder connections inside the housing. However, these materials can only be electroplated with great difficulty to ensure firm adhesion. Furthermore, improving solderability through a preferably selective coating (e.g., by a wet electroplating process) is technically difficult and therefore cost-intensive.

[0008] A feedthrough for a battery is known from US 2004 / 0101746 A1, in which a conductor is protected from the electrolyte by a covering.

[0009] US Pat. No. 9,741,463 B2 shows a feedthrough for harsh environmental conditions, in which a conductor is embedded in a glass or glass ceramic material together with a sleeve element surrounding the conductor.

[0010] Likewise known from US 2002 / 0155350 A1 is a glass-metal feedthrough in which a sleeve element surrounds a conductor and the conductor and the sleeve element are introduced together into a glass or glass ceramic material. Summary of the Invention

[0011] The object of the present invention is therefore to provide a glass-metal feedthrough which avoids the disadvantages of the prior art. In particular, a feedthrough with a metal pin or inner conductor is to be provided which, on the one hand, does not release nickel when in contact with the human body and, on the other hand, is sufficiently solderable.

[0012] This object is achieved by a glass-metal feedthrough according to claim 1 , by the use of a glass-metal feedthrough according to claim 7 , and by an element according to claim 8 having a glass-metal feedthrough according to the invention which can be introduced into the human or animal body or into cell cultures.

[0013] The glass-metal feedthrough according to the present invention is unique in that it comprises an outer conductor (also referred to as a substrate), a glass material or glass ceramic, and an inner conductor, preferably a metal pin, embedded in the glass or glass ceramic material. The inner conductor or metal pin is inserted into the outer conductor or substrate and fused into the glass or glass ceramic material.

[0014] The material of the metal pin according to the present invention includes a material having high electrical conductivity and / or low contact resistance.

[0015] Furthermore, the metal pin or the inner conductor comprises a sleeve element which at least partially, preferably completely, surrounds the metal pin or the inner conductor. The sleeve element is only arranged on a portion of the metal pin and is essentially used to provide a low-resistance connection between the metal pin and the conductor material (e.g. in a printed circuit, a so-called PCB). P rinted C ircuit B The sleeve material is the interface wetted by the solder during soldering.

[0016] It is particularly preferred that the sleeve element is not only plugged onto the metal pin and the metal pin is partially enclosed by the sleeve element, but that the sleeve element and the metal pin are crimped together. This crimping ensures that the sleeve element remains in position on the metal pin and does not slip. During crimping, the sleeve element and the metal pin are crimped together using a crimping tool, crimping pliers, or a pressure press. This crimping secures the sleeve element to the metal pin.

[0017] According to the invention, the metal pin of the glass-metal feedthrough has two ends, a first end embedded in the glass or glass material and a second end receiving a sleeve, wherein the second end can be inserted or soldered together with the sleeve into an electrical terminal.

[0018] It is particularly preferred that the material of the sleeve comprises a solderable material, such as copper or nickel, since thereby the sleeve can be soldered to the electrical contact when the sleeve is inserted into the electrical connection, such as an opening of a printed circuit (PCB).

[0019] It is particularly preferred that the metal pin comprises a medically harmless material, so that it can be used for medical applications. A very conductive, medically harmless and otherwise low-contact-resistance material is, for example, niobium, titanium, tantalum, stainless steel, in particular ferritic stainless steel, or molybdenum, as a material for the metal pin.

[0020] If the metal pin is produced from a material such as niobium, titanium, tantalum or molybdenum without a sleeve, the material, although it is a non-allergic, highly conductive material, can only be poorly soldered together with the conductor.

[0021] According to the application, this problem is solved by pressing a sleeve element formed from a solderable material, such as copper, onto a metal pin formed from niobium, titanium, tantalum, stainless steel or molybdenum. The advantage of using the materials niobium, titanium, tantalum, stainless steel or molybdenum for the metal pin is not only the high electrical conductivity, but also the fact that such materials do not show galvanic corrosion in practice. The advantage of arranging a separate sleeve element or sleeve on the metal pin is that the well-solderable material does not seep out and come into contact with people. In addition to niobium, titanium, tantalum, stainless steel and molybdenum, tungsten is also suitable as a material for the metal pin. The expansion coefficient of niobium is approximately 7*10 -6 1 / K and the expansion coefficient of molybdenum is approximately 5*10 -6 1 / K.

[0022] The expansion coefficient of the metal pin is α 内 Preferably, it is in the range of 4 to 13 ppm / K, that is to say from 4*10 -6 1 / K to 13*10 -6 1 / K. In contrast to the material used for the metal pin, the material of the sleeve, such as copper, has a higher expansion coefficient.

[0023] Due to the large difference in the coefficient of thermal expansion, it is to be expected that the sleeve consisting of copper expands more intensely than the metal pin formed from niobium or molybdenum due to the higher expansion coefficient and loses contact with the metal pin at temperatures greater than 600°C when the metal pin is inserted.

[0024] Surprisingly, it has been determined that even after high-temperature treatment, the copper sleeve remains intact from the metal pin under minimal crimping. This is attributed to diffusion bonding, and therefore a chemical connection between the copper and the metal pin, rather than just crimping. The typical temperatures of 800-1000°C used to create glass-to-metal connections are also optimal for driving the sleeve toward the pin. The higher the temperature, the better the diffusion anchoring effect. Therefore, in this case, a separate process step for diffusion anchoring the sleeve is unnecessary. The diffusion and mounting processes proceed in parallel.

[0025] Particularly preferably, due to the embedding of the metal pins, the thickness of the feedthrough is less than 1 mm. This is achieved in particular with a base body formed from metal, ceramic and / or glass.

[0026] When the contact pins are connected to the base body by means of a polymer material, for example by overmolding, at least 2 mm is required to achieve, for example, a water pressure resistance of 5 bar. Thinner glass-metal feedthroughs made of metal therefore require significantly less space, and metal is therefore preferred as the material for the base body.

[0027] The advantage of using niobium, titanium, tantalum, and molybdenum as materials for the metal pins is that the solder does not rise due to wetting but is instead confined only to the region of the sleeve element or sleeve. Confining the solder to the sleeve region has the further advantage that the soldering process can be better controlled than if, for example, the entire metal pin were made of copper.

[0028] The glass-metal feedthrough according to the invention is primarily used in wearable devices, implantable medical instruments or devices in which both the outer conductor and the inner conductor are in contact with the human or animal body in the operating state at least in the surface region.

[0029] According to the invention, the design of the metal pin has a reduced allergenic potential, in particular because no nickel or chromium is leached from the metal pin. In addition to the materials mentioned above, stainless steel, in particular ferritic stainless steel, can also be used for the metal pin.

[0030] It is particularly preferred that the outer conductor or the base body of the glass-metal feedthrough is austenitic stainless steel, preferably stainless steel 316L, which is distinguished by good weldability and a high coefficient of expansion.

[0031] The metal pins formed by niobium or molybdenum have a -6 1 / K to 7*10 -6The expansion coefficient of the outer conductor or the base body is preferably selected such that a bonding pressure of at least 30 MPa, preferably at least 50 MPa, and in particular at least 100 MPa is achieved on the inner conductor or the metal pin.

[0032] In this case, this involves pressure mounting. However, the present invention can also be used in matching feedthroughs. In this case, mounting is possible not only in metallic materials but also in ceramic materials. Mounting in ceramics is only possible under certain conditions by means of pressure prestressing the glass.

[0033] The present invention further comprises the use of the glass-metal feedthrough according to the invention in implantable medical instruments or devices, and a component which can be introduced into the human or animal body or into a cell culture comprising living biological cells or which can be applied to the human or animal body or onto a cell culture comprising living biological cells, the component comprising the glass-metal feedthrough according to the invention, wherein the outer conductor and the inner conductor consist of a material with reduced allergenic potential, in particular a metal, at least in their surface region which comes into contact with the human or animal body in the operating state.

[0034] The material of the outer conductor or base body and the material of the inner conductor or metal pins can come into contact with the human or animal body or cell cultures and are preferably characterized by not releasing nickel and / or chromium.

[0035] The material of the outer conductor, at least in the surface area that comes into contact with the human or animal body or biological cells of a cell culture in the operating state, comprises nickel-free and / or chromium-free stainless steel and / or austenitic stainless steel and / or ceramic and / or glass / glass ceramic. Particularly preferred are materials that meet the test requirements for the permissible nickel content according to DIN EN 1811 and DIN EN 12472.

[0036] The material of the inner conductor, at least in its surface area that comes into contact with the human or animal body or biological cells of a cell culture in the operating state, comprises nickel-free and / or chromium-free stainless steel and / or niobium and / or titanium and / or tantalum and / or tungsten. Particularly preferred are materials that meet the test requirements for the permissible nickel content according to DIN EN 1811 and DIN EN 12472. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention will be explained in more detail below with reference to the accompanying drawings.

[0038] In the attached figure:

[0039] Figure 1 A schematic diagram showing a metal pin with a sleeve element according to the present invention; and

[0040] Figure 2 A schematic diagram of a metal pin according to the invention with a sleeve element is shown in a feed-through. DETAILED DESCRIPTION

[0041] exist Figure 1 Schematic diagram of a metal pin 1 with a sleeve element 2 of the present invention is shown in FIG. The metal pin 1 comprises a material having high electrical conductivity and biocompatibility, such as niobium, titanium, tantalum, molybdenum, stainless steel or tungsten.

[0042] Metal pin 1 has two ends, a first end 10 and a second end 20. In the case of a glass-to-metal feedthrough, first end 10 of metal pin 1 is typically embedded in a glass or glass-ceramic material. According to the present invention, sleeve element 2 or sleeve is preferably attached to second end 20 of metal pin 1 by pressing, wherein heating can also cause the metal of sleeve element 2 to fuse with metal pin 1. Suitable materials for sleeve element 2 include any material that can be well welded to electrical contacts, for example. Well-weldable materials include copper, nickel, and the like.

[0043] exist Figure 2 In the Figure 1 The figure shows the use of a metal pin 1 according to the invention in a glass-metal feedthrough, wherein the metal pin 1 according to the invention is connected to an electrical contact, in the embodiment shown, a printed circuit board (PCB) 5. According to the invention, the first end 10 of the metal pin 1 is embedded in a glass or glass-ceramic material 3, thereby producing a glass-metal feedthrough. The glass material 3 is surrounded by an outer conductor or base body 4. The material for the base body 4 can be, for example, metal, in particular stainless steel, but can also be ceramic. When metal is used, pressure embedding occurs due to the different expansion coefficients of the metal of the base body 4 and the glass material 3. However, a matching feedthrough is also possible when a ceramic material is used for the base body 4, for example.

[0044] The thickness of the base body 4 with the embedded metal pin 1 is typically less than 1 mm. The sleeve 2 surrounds the metal pin 1 at its uninserted second end 20 and is inserted into an opening in the conductor material, here a printed circuit board (PCB) 5. The first end 10 of the metal pin 1 is introduced into the glass or glass ceramic material 3.

[0045] The present invention provides for the first time a metal pin 1 having the following characteristics: high biocompatibility, high electrical conductivity, very good solderability and high corrosion resistance.

[0046] The present invention comprises various aspects claimed in the following specifications which form part of the description but are not included in the claims.

[0047] plan

[0048] 1. A glass-metal feedthrough, the glass-metal feedthrough

[0049] The invention comprises an outer conductor or a base body (4), a glass material or a glass ceramic material (3) and an inner conductor, wherein the inner conductor is preferably a metal pin (1) and the inner conductor is embedded in the glass or glass ceramic material (3) in the outer conductor, in particular in the base body (4).

[0050] It is characterized by:

[0051] The metal pin (1) comprises a material having high electrical conductivity and / or low contact resistance, and a sleeve element (2) which at least partially surrounds the metal pin (1).

[0052] 2. A glass-metal feedthrough according to claim 1,

[0053] It is characterized by:

[0054] The sleeve element (2) is crimped to the metal pin (1).

[0055] 3. A glass-metal feedthrough according to claims 1 to 2,

[0056] It is characterized by:

[0057] The material of the sleeve element comprises a solderable material, in particular copper or nickel.

[0058] 4. A glass-metal feedthrough according to any one of claims 1 to 3,

[0059] It is characterized by:

[0060] The metal pin (1) comprises a medically harmless material, in particular one of the following materials:

[0061] Niobium, molybdenum, titanium, tantalum, stainless steel and tungsten.

[0062] 5. A glass-metal feedthrough according to any one of claims 1 to 4,

[0063] It is characterized by:

[0064] The metal pin (1) has two ends, a first end (10) and a second end (20), wherein the first end is embedded in the glass or glass ceramic (3) and the second end (20) receives the sleeve element (2).

[0065] 6. A glass-metal feedthrough according to any one of claims 1 to 5,

[0066] characterized in that

[0067] the expansion coefficient a of the metal pin (1) 内 in the range of 4 to 13 ppm / K.

[0068] 7. Use of a glass-metal feedthrough according to any one of solutions 1 to 6 in a wearable device, in an implantable medical instrument or device.

[0069] 8. An element which can be introduced into the human or animal body or into a cell culture comprising living biological cells or which can be applied to the human or animal body or to a cell culture comprising living biological cells, the element having a glass-metal feedthrough according to any one of solutions 1 to 6, wherein the outer conductor and the inner conductor consist of a material, in particular a metal, having a reduced allergenic potential at least in the surface area thereof which in the working state comes into contact with the human or animal body.

[0070] 9. Element according to solution 8, wherein the material of the outer conductor and of the inner conductor which comes into contact with the human or animal body or with the cell culture does not deposit nickel and / or chromium.

[0071] 10. Element according to at least one of solutions 7 to 8, wherein the material of the outer conductor and of the inner conductor comprises nickel-free and / or chromium-free stainless steel and / or austenitic stainless steel and / or ceramic and / or glass and / or glass ceramic at least in the surface area thereof which in the working state comes into contact with the human or animal body or with the biological cells of a cell culture.

Claims

1. A glass-metal feedthrough comprising an outer conductor (4), a glass or glass ceramic material (3) and an inner conductor, wherein the inner conductor is a metal pin (1) and the inner conductor is embedded in the glass or glass ceramic material (3) in the outer conductor (4), wherein the metal pin (1) comprises a material with high electrical conductivity and / or low contact resistance, and a sleeve element (2) which at least partially surrounds the metal pin (1), It is characterized by: The metal pin (1) has two ends, namely a first end (10) and a second end (20), wherein the first end is embedded in the glass or glass ceramic material (3) and the second end (20) receives the sleeve element (2), wherein The sleeve element (2) comprises copper or nickel as a solderable material and is plugged onto the metal pin (1), diffusion bonding exists between the sleeve element (2) and the metal pin (1), and the sleeve element (2) is crimped to the metal pin (1).

2. The glass-metal feedthrough according to claim 1, wherein The metal pin (1) comprises one of the following materials as a medically harmless material: niobium, molybdenum, titanium, tantalum, stainless steel and tungsten.

3. The glass-metal feedthrough according to claim 1 or 2, characterized in that The expansion coefficient α of the metal pin (1) 内 In the range of 4 to 13 ppm / K.

4. The glass-metal feedthrough according to claim 1, wherein: The sleeve element (2) does not extend beyond the metal pin (1).

5. The glass-metal feedthrough according to claim 1, wherein: The sleeve element (2) is not embedded in the glass or glass ceramic material (3).

6. The glass-metal feedthrough according to claim 1, wherein: The glass-metal feedthrough further comprises a printed circuit board having an opening, wherein the sleeve element (2) at least partially surrounding the metal pin (1) is arranged within the opening of the printed circuit board.

7. The glass-metal feedthrough according to claim 6, wherein: The openings in the printed circuit board are electrical contacts, which are soldered to the sleeve element (2).

8. Use of the glass-metal feedthrough according to any one of claims 1 to 7 in a wearable device or an implantable medical instrument or device.

9. A component that can be introduced into a human or animal body or a cell culture containing living biological cells or can be applied to a human or animal body or a cell culture containing living biological cells, the component comprising a glass-metal feedthrough according to any one of claims 1 to 7, wherein the outer conductor and the inner conductor consist of a material with reduced allergenic potential, at least in their surface areas that come into contact with the human or animal body in the operating state.

10. The component according to claim 9, wherein the materials of the outer conductor and the inner conductor that come into contact with the human or animal body or the cell culture do not precipitate nickel and / or chromium.

11. The element according to claim 9 , wherein the material of the outer conductor and the inner conductor comprises nickel-free and / or chromium-free stainless steel and / or austenitic stainless steel and / or ceramic and / or glass and / or glass ceramic, at least in their surface areas which, in the operating state, come into contact with the human or animal body or the biological cells of the cell culture.

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