Hermetically sealed controlled impedance feedthrough assembly

Abstract

A hermetically sealed controlled impedance feedthrough assembly (10) for passing controlled impedance electrical signals between two different environments (1, 2) via a feedthrough (11) in a feedthrough block (30). The feed-through (11) has a signal coupling (61), a dielectric (53) surrounding the signal coupling (61), and a ground coupling (70) surrounding the dielectric (53). An electrically insulating block (30) has an electrically conductive signal link (62) and a discrete electrically conductive ground link (71) surrounding the signal link (62). The electrically conductive block has a separate dielectric spacer (54) and a signal link (62) passing through the spacer (54). The joints between the blocks (30), links (62, 71) and spacers (54) are sealed to hermetically separate the two environments (1, 2). In one method, mating components are press-fitted without leaving a gap between adjacent components. In another method, potting material (60) is forced into the junctions between the components.

Description

[0001] This application is a divisional application of the invention patent application with the application date of September 17, 2020, application number 202080065200.9, and invention name “Hermetically Sealed Controlled Impedance Feedthrough Assembly”. Technical Field

[0002] The present invention relates to cable feedthrough assemblies and, more particularly, to controlled impedance cable feedthroughs which are commonly used to transmit high frequency signals between different physical environments. Background Art

[0003] In some situations, signals must be fed between different environments. Examples include between environments with gases at different atmospheric pressures, environments with different atmospheric pressures, and environments with different degrees of sterility. In this case, the interface must be hermetically sealed so that the environments do not mix or so that one environment does not contaminate another environment.

[0004] In the prior art, individual coaxial connectors such as SMA or SMP are used to transmit signals between environments. These connectors are quite large, with a diameter of 0.25 inches to 0.5 inches. Since they cannot be closer to each other than their maximum diameter, the number of connectors per unit area separating the environments, the density, is quite low. Summary of the invention

[0005] This specification describes an assembly for passing signals between two different environments. The signal, typically an RE, passes through a first connector in the first environment, through a feedthrough in a flange separating the two environments, and through a second connector in the second environment. Each connector terminates one or more controlled impedance cables.

[0006] The connector has several embodiments, a representative one of which has an anchor block for securing a cable, a compliant signal contact for making an electrical connection between the cable signal conductor and the feedthrough, an optional compliant ground contact for making an electrical connection between the cable shield and the feedthrough, and a plate mounted to the anchor block 88 to maintain contact.

[0007] The conductive anchor block provides a common ground for cables that are permanently or removably attached to the anchor block. Alternatively, the anchor block is non-conductive and only provides anchoring for the removably attached cables 20.

[0008] The connector can be designed to be used with any number of different compliant contacts. The plates remain in contact and can be made of conductive or electrically insulating materials. When the connector is assembled, the plates abut the anchor block face 92, and typically abut the feed-through block when the connector is connected to the feed-through block. The signal contacts are captured in through-apertures in the plates. If the plates are conductive, the signal contacts are insulated from the plates. Before the plates are assembled to the anchor blocks, the contact points of the signal contacts extend from each side of the plates. Each ground contact is captured in a ground through-aperture. Before the plates are assembled to the anchor blocks, the contact points of the ground contacts extend from each side of the plates.

[0009] The signal travels through the flange via the feedthrough in the feedthrough block. The feedthrough has three components: a signal coupling, a dielectric surrounding the signal coupling, and a ground coupling surrounding the dielectric. If the block is electrically insulating, the block itself can act as the dielectric. If the block is conductive, a separate dielectric is required.

[0010] A feed-through without a separate dielectric has a signal through-aperture in the block of a signal link, which is a conductive wire or pin. The end of the signal link is a contact point for a signal contact of a connector. Optionally, during installation or if the first environment is at a higher pressure than the second environment, the signal link and the signal aperture are shaped to prevent the signal link from being pushed through the signal aperture.

[0011] The feedthrough with separate dielectric has a spacer through-aperture in a block with dielectric in the form of a dielectric spacer. Optionally, the spacer aperture and the spacer are shaped to prevent the spacer from being pushed through the spacer aperture during installation or if the first environment is at a higher pressure than the second environment. The spacer has a signal through-aperture for a signal link.

[0012] Typically, the apertures, spacers, and signal links are sized to provide impedance matching for the signal using methods well known in the art. For accurate impedance matching, the dielectric must be surrounded by the system ground plane. If the block is conductive, no specific adjustments for the ground signal are required. Non-conductive blocks must feed the ground signal through the block via a ground coupling.

[0013] The ground coupling may include discrete conductive ground links extending through ground apertures in the block. An appropriate number of ground links surround the signal link. The ground links are conductive wires or pins. Alternatively, the ground links are plated through holes. In another configuration, the ground coupling is a conductive ground fiber ferrule installed in a block surrounding the spacer through an aperture. In another configuration, the walls of the spacer aperture are coated with a conductive material.

[0014] The various components are mounted with hermetic seals that hermetically separate the two environments. In one approach, the various components are press-fit into corresponding apertures, leaving no gaps between adjacent components.

[0015] In another approach, the spacer is shorter than the spacer aperture so that one or both faces of the spacer are recessed from the corresponding block surface, thereby leaving a gap between the spacer and the block surface. One or both of the gaps are potted to seal the spacer aperture and surround the signal link, thereby creating a hermetic seal. Typical potting materials are two-part epoxies. The minimum depth of each gap depends on the environment and the potting material and is typically not less than 0.01 inches. The plated through holes are hermetically sealed by filling the plated through holes with potting material or solder.

[0016] One method of potting involves applying a vacuum to one surface of the block and allowing the vacuum to pull the potting material from the opposite side, thereby forcing the potting material into all gaps and interfaces between components. The vacuum ensures that the potting material is forced into all spaces that would provide a leak path. Alternatively, pressure is applied to the potting material at one surface to push the potting material into all spaces that would provide a leak path.

[0017] The invention contemplates the flange being a block, that is to say the feed-through extends through the flange itself. Alternatively, the block is a separate component that is hermetically sealed into an opening in the flange.

[0018] The objects of the present invention will become apparent from the following drawings and detailed description of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] For a more complete understanding of the nature and purpose of the present invention, reference is made to the accompanying drawings, in which:

[0020] Figure 1 is a cross section of an embodiment;

[0021] Figure 2 for Figure 1 Details;

[0022] Figure 3 for Figure 1 a cross-sectional view of a section of a configuration of a connector having a permanently attached cable;

[0023] Figure 4 a cross-sectional view of a section of a configuration of a connector having a removable ground cable;

[0024] Figure 5 is a cross-sectional view of a section of another configuration of a connector having a removable ground cable;

[0025] Figure 6 is a cross-sectional view of a section of another configuration of a connector having a removable ground cable;

[0026] Figure 7 is a cross-sectional view of one configuration of a plate having portions of anchor blocks and cables;

[0027] Figure 8 is a cross-sectional view of another configuration of a plate having portions of anchor blocks and cables;

[0028] Fig. 9 is a cross-sectional view of an insulating plate having a fuzz button contact;

[0029] Fig.10 is a cross-sectional view of an insulating plate having conductive rubber contacts;

[0030] Fig.11 For Fig.10 A cross-sectional view taken at EE of ;

[0031] Fig.12 For Fig.11 A cross-sectional view taken at FF;

[0032] Fig.13 is a bottom view of an insulating plate having embedded stamped or etched contacts;

[0033] Fig.14 is intercepted at H Fig.13 a detailed view of a bottom portion of a coaxial cable termination assembly;

[0034] Fig.15 for Fig.13 a cross-sectional view of a plate; and

[0035] Fig.16 A cross-sectional view of an insulator plate with embedded molded or etched contacts, with one side mated to a cable and compressed contacts.

[0036] Fig.17 is a cross section of the block separated from the flange;

[0037] Fig.18 is a cross section of a basic feedthrough without a separate dielectric;

[0038] Fig.19 for Fig.18 A top view of a feedthrough;

[0039] Fig. 20 A cross section of a feedthrough having alternative configurations of a signal link and a signal aperture;

[0040] Fig.21 A cross section of a feedthrough having alternative configurations of a signal link and a signal aperture;

[0041] Fig. 22 is the cross section of the basic feedthrough;

[0042] Fig.23 for Fig. 22A top view of a feedthrough;

[0043] Fig.24 A cross section of a feedthrough having an alternative configuration of several components;

[0044] Fig.25 for Fig.24 A top view of a feedthrough;

[0045] Fig.26 A cross section of a feedthrough having an alternative configuration of several components;

[0046] Fig. 27 A cross section of a feedthrough having an alternative configuration of several components;

[0047] Fig.28 is a cross-sectional view of a feedthrough with a ground link;

[0048] Fig.29 is a top view of a feedthrough having a ground link surrounding a signal link and a spacer;

[0049] Fig.30 is a cross-sectional view of a PCB block having a ground link;

[0050] Fig.31 is a top view of a feedthrough having a ground link in a ground plane;

[0051] Fig.32 is a cross-sectional view of a feed-through having a grounded fiber ferrule;

[0052] Fig.33 is a cross section of a feedthrough having a plated aperture and a ground pad;

[0053] Fig.34 is the cross section of the block as part of the flange;

[0054] Fig.35 is a top view of the flange as a block;

[0055] Fig.36 is a top view of a flange with independent blocks;

[0056] Fig.37 is a top view of a flange with a PCB as a block;

[0057] Fig.38 is a cross-sectional view showing the connection of the connector to the feed-through block;

[0058] Fig.39 is a cross-sectional view of another embodiment;

[0059] Fig.40 For a connector with an attachment Fig.39A cross-sectional view of an embodiment of; and

[0060] Fig.41 For a connector with an attachment Fig.39 Another cross-sectional view of an embodiment of. DETAILED DESCRIPTION

[0061] This specification describes an assembly 10 for transmitting signals between a first environment 1 and a second environment 2 separated by a barrier 3. The two environments 1, 2 may differ in many respects. For example, there may be pressures, temperatures, or chemical compounds on both sides of the barrier 3 that will not mix in some applications. An example of this is feeding data into and out of a cold computing environment, such as a quantum computing environment. The first environment 1 is typically at normal atmospheric pressure and room temperature. In a quantum computing environment, the second environment 2 is in a near perfect vacuum. The region of the second environment 2 closest to the first environment 1 is close to room temperature, and the temperature of the region farthest from the first environment 1 is maintained between 4 Kelvin and 4 millikelvin.

[0062] like Figure 1 and 2 As shown in FIG. 1 , a signal is transmitted between environments 1 and 2 through a first connector 14 in the first environment 1, a flange 12 separating the two environments 1 and 2, and a second connector 16 in the second environment 2. The signal is typically a radio frequency, RF signal. Although the upper limit of the radio frequency range that the present invention can adopt is constantly improving, the signal speed can be as low as a few hundred MHz to as high as 70 GHz depending on the application.

[0063] Each connector 14, 16 terminates one or more controlled impedance cables 20. A controlled impedance coaxial cable 20 has a signal conductor 22 surrounded by a dielectric 24 having a ground referenced shield 26 outside the dielectric 24. Optionally, a jacket 28 covers the shield 26. A controlled impedance twinaxial cable 20 has two signal conductors 22 surrounded by a dielectric 24 having a ground referenced shield 26 outside the dielectric 24 and a jacket 28 covering the shield 26. In order to properly terminate the cables 20, the cable ground shield 26 must be electrically coupled to the connectors 14, 16. Optionally, as shown in FIG. Figure 2 , the fiber ferrule 90 may be mounted on the ground shield 26. A controlled impedance cable 20 having more than two signal conductors 22 may be used. Although not specifically described, the present invention may be adapted to accommodate cables 20 having any number of signal conductors 22.

[0064] The flange 12 is removably mounted into an opening in the barrier 3 separating the two environments 1, 2. The flange 12 is mounted in any manner that provides an acceptable airtight seal between the flange 12 and the barrier 3. Methods of mounting are well known in the industry. Alternatively, the barrier 3 is incorporated into the flange 12, that is, the barrier 3 and the flange 12 are not separate components.

[0065] The signal travels through the flange 12 via the feedthrough 11 in the feedthrough block 30. The connectors 14, 16 provide an interface between the controlled impedance coaxial cable (hereinafter, simply "cable") 20 and the feedthrough 11. Different configurations of the connectors 14, 16 are described in U.S. Pat. Nos. 8,926,342 and 9,160,151, both of which are incorporated herein by reference. Several configurations are summarized below. Only one connector 14 is referenced below.

[0066] The connector 14 has several embodiments, a representative one of which has an anchor block 88 for securing the cable 20, a compliant signal contact 86 for making an electrical connection between the cable signal conductor 22 and the feedthrough 11, an optional compliant ground contact 87 for making an electrical connection between the cable shield 26 and the feedthrough 11, and a plate 89 mounted to the anchor block 88 to retain the contacts 86, 87.

[0067] In a configuration such as Figure 3 , the anchor block 88 is conductive and provides a common ground for the permanently attached cables 20. The ground shields 26 of all cables 20 are electrically connected to the anchor block 88 in the hole 91 in the anchor block 88. Any suitable method may be used, including: soldering, crimping, potting with a conductive adhesive, insert molding the anchor block 88 in place with the cables 20 during molding, and press-fitting (e.g., pre-tinning) the rigidized ground shield 26 into the hole 91.

[0068] Once the cable 20 is anchored in the anchor block 88, the face 92 of the anchor block 88, the signal conductor 22, and the dielectric 24 are appropriately trimmed to make reliable electrical contact with the compliant contacts 86, 87. The anchor block face 92, the signal conductor 22, and the dielectric 24 may need to be polished and planarized by some mechanical means, such as by milling, grinding, or lapping, in order to ensure that the cable center conductor 22 and the dielectric 24 are positioned at a known depth relative to the anchor block face 92, in this case flush with the anchor block face 92. The anchor block face 92 and the signal conductor 22 may also require precious metal plating to prevent the polished surface from oxidizing or otherwise degrading, thereby inhibiting acceptable electrical connection of the contacts 86, 87 to the signal conductor 22 and the anchor block 88.

[0069] In another configuration, the anchor block 88 is either conductive or non-conductive and provides only anchoring for the removably attached cable 20. Figures 4 to 6 2 and 3. Methods of removably attaching the cables 20 to the anchor blocks 88 are shown in FIG. These methods permit replacement of individual cables 20, thus eliminating the need to replace the entire assembly.

[0070] Figure 4The first method illustrated in FIG. 1 requires the attachment of a fiber ferrule at or near the end of the cable 20 for trimming the cable end. The jacket 28 is stripped and a threaded fiber ferrule 94 is slid over the shield 26. The fiber ferrule 94 is attached to the cable 20 by welding, crimping, or other mechanical means of electrically coupling the fiber ferrule 94 to the shield 26. The fiber ferrule face 95, the signal conductor 22, and the dielectric 24 are then trimmed as described above with reference to the anchor block 88. The fiber ferrule 94 is screwed into the threaded hole 96 in the anchor block 88 until the signal conductor 22 is pressed against the signal contact 86 so as to create an electrical connection between the signal conductor 22 and the signal contact 86.

[0071] A second method of removably attaching the cable 20 to the anchor block 88 entails the use of a twist-lock attachment 100, such as Figure 5 . The twist lock assembly 102 slides over the cable 20 so that the assembly 102 can slide freely over the cable 20. The coil spring 104 slides over the cable 20. After the jacket 28 is stripped, the fiber ferrule 106 is attached to the shield 26 by welding, crimping, or other mechanical method of electrically coupling the fiber ferrule 106 to the shield 26. The fiber ferrule face 108, signal conductor 22, and dielectric 24 are then trimmed as described above with reference to the anchor block 88.

[0072] The fiber optic ferrule 106 / cable 20 is inserted into the hole 110 in the anchor block 88. The protrusion 112 from the twist-lock assembly 102 slides down the side of the hole 110 relative to the groove (not shown) until it is aligned with the annular recess 114 in the hole 110. With this alignment, the spring 104 is compressed so that it presses the signal conductor 22 into the signal contact 86 to create an electrical connection between the signal conductor 22 and the signal contact 86. The twist-lock assembly 102 is rotated so that the protrusion 112 is captured by the annular recess 114, thereby retaining the cable 20 in the hole 110.

[0073] Figure 6 Another method of removably attaching the cable 20 to the anchor block 88 is shown in FIG. 1 . The fiber optic ferrule 120 is attached to the cable 20 and trimmed as described above. The fiber optic ferrule 120 has an annular ridge 122 at or away from the end 124 of the fiber optic ferrule 120, such as Figure 6. The anchor block 88 has two sections, a bottom section 126 and a top section 128. The upper end of the cable hole 130 in the bottom section 126 has an annular groove 132. When the fiber ferrule 120 / cable 20 assembly is inserted into the cable hole 130, the ridge 122 fits into the groove 132, with the fiber ferrule face 134, signal conductor 22 and dielectric 24 flush with the block face 92. The block top section 128 is mounted on the bottom section 126 and attached via screws, clamps or any other acceptable method. The top section 126 captures the fiber ferrule 120 / cable 20 assembly in the anchor block 88. Optionally, the ridge 122 and groove 132 may be keyed to prevent the fiber ferrule 120 / cable 20 assembly from rotating in the cable hole 130.

[0074] In some cases, particularly in the case of a removable attachment, the signal conductor 22 and / or the dielectric 24 may not be exactly flush with the anchor block face 92, that is, they may be slightly recessed into the anchor block face 92 or protrude from the anchor block face 92. The recess or protrusion may be as much as 0.05 inches. This specification and claims use the term "flush" to indicate that the signal conductor 22 and the dielectric 24 are actually flush with the anchor block face 92, slightly recessed into the anchor block face 92 by up to 0.05 inches, or slightly protruding from the anchor block face 92.

[0075] Connector 14 may be designed for use with any number of different compliant contacts, including, but not limited to, skewed coil contacts, fuzz button contacts, conductive rubber contacts, and conductive ribbon contacts. Figures 3 to 8 A connector as designed for use with a skew coil contact is shown. Various types and configurations of skew coil contacts are described in U.S. Patent Nos. 7,126,062 and Re 41,663, both of which are incorporated herein by reference. In brief, a skew coil contact comprises a coil of conductive, inherently elastic wire having a pair of oppositely extending leads. The leads extend in a direction that is angled with the coil axis. During compression, the coil rings are electrically shorted together as they slide along each other.

[0076] Figure 7 and 8 The plate 89 shown in Figure 1 holds the contacts 86, 87 and may be constructed of an electrically conductive or electrically insulating material.

[0077] The plate 89 has a block surface 154 that abuts the anchor block face 92 when the connector 14 is assembled and a feedthrough surface 156 that typically abuts the feedthrough block 30 when the connector 14 is connected to the feedthrough block 30. Typically, the plate 89 is attached to the anchor block face 92 by screws 216.

[0078] like Figure 7, the signal contact 86 is captured in a through aperture 160 in the plate 89. The signal through aperture 160 has a larger central section 166 that narrows to a smaller signal block opening 168 in the block surface 154 and to a smaller signal feedthrough opening 170 in the feedthrough surface 156. The coil 140 of the contact 86 is captured in the central section 166. Before the plate 89 is assembled to the anchor block 88, the block contact point 142 of the signal contact 86 extends from the signal block opening 168. Before the connector 14 is connected to the feedthrough block 30, the feedthrough contact point 144 of the signal contact 86 extends from the signal feedthrough opening 170.

[0079] If the board 89 is conductive, the signal through-aperture 160 is within an insulating plug 162 which prevents the signal contact 86 from being electrically shorted to the board 89. The plug 162 is typically made of insulating plastic. The plug 162 fits into a signal through-hole 164 in the board 89.

[0080] After the plate 89 is assembled to the anchor block 88 , each signal block opening 168 is aligned with its corresponding cable hole 91 in the anchor block 88 .

[0081] Each ground contact 87 is captured in a ground through-aperture 190. Each ground through-aperture 190 has a larger central section 192 that narrows to a smaller ground block opening 194 in the block surface 154 and to a smaller ground feedthrough opening 196 in the feedthrough surface 156. The coil 146 of the ground contact 87 is captured in the central section 192. Before the board 89 is assembled to the anchor block 88, the block contact point 148 of the ground contact 87 extends from the ground block opening 194. Before the connector 14 is connected to the feedthrough block 30, the feedthrough contact point 150 of the ground contact 87 extends from the ground feedthrough opening 196.

[0082] When constructed of a conductive material, the plate 89 electrically couples the ground contact 87 , thereby providing a more precise impedance match with the signal contact 86 .

[0083] exist Figure 7 In the configuration of FIG. 8 , the board 89 has two mirror-image sheets 200, 202. The bottom sheet 200 has the feed-through openings 170, 196 and half of the center section 166, 192, and the top sheet 202 has the block openings 168, 194 and half of the center section 166, 192. The contacts 86, 87 are placed in the center section 166, 192 of one sheet 200, and the sheets 200, 202 are clamped together to capture the contacts 86, 87.

[0084] exist Figure 8In the configuration of FIG. 8 , the board 89 has a bottom sheet 204 having the feed-through openings 170, 196 and all of the center sections 166, 192 and a top sheet 206 having only the block opening 168. The contacts 86, 87 are placed in the center sections 166, 192 of the bottom sheet 204, and the sheets 204, 206 are sandwiched together to capture the contacts 86, 87.

[0085] When an insulating plug 162 is used, it may be press-fit into a through-hole 164 in the plate 89 or it may be bonded into the through-hole 164 with an adhesive. Figure 7 As shown in FIG. 1 , the plug 162 has two parts 174, 176, each of which fits into one plate sheet 200, 202. Mating shoulders 178, 180 retain the plug parts 174, 176 in the plate sheets 200, 202. Alternatively, as Figure 8 As shown in FIG. 1 , the plug 162 has a lower portion 182 and an upper portion 184 that fit into the lower sheet 204 and the upper sheet 206 , respectively.

[0086] The mating shoulders 186 , 188 retain the plug portions 182 , 184 in the plate laminae 204 , 206 .

[0087] As mentioned above, a velvet button contact may be used. Fig. 9 As shown in FIG. 8 , the velvet button contact 220 is cylindrical. The plate 89 has a through aperture 160 that is narrower at the center than at the ends, such as at 224. The contact 220 is forced into the aperture 160. The length of the contact 220 is such that the end 226 extends from the plate 89.

[0088] As mentioned above, conductive rubber contacts can be used. Figures 10 to 12 As shown, the conductive rubber contact 230 for the signal contact 86 may be cylindrical with a centrally located annular recess 232. The plate 89 has a through aperture 160 with a centrally located annular protrusion 236. The conductive rubber contact 230 is radially compressed and placed in the aperture 160 so that the protrusion 236 fits into the recess 232 to retain the contact 230 in the aperture 160. The length of the contact 230 is such that the end 238 extends from the plate 89.

[0089] The conductive rubber contact 242 for the ground contact 87 may have the same structure as the signal contact 86. Alternatively, the conductive rubber contact 242 for the ground contact 87 is circular and surrounds the signal contact 86, such as Fig.11The conductive rubber contact 242 has a circular top tab 244 adjacent to the anchor block 88 and a circular bottom tab 246 for interfacing to the feedthrough block 30. The two tabs 244, 246 are electrically connected by a plurality of plugs 248 in through apertures 250 in the plate 89. The number of plugs 248 may vary depending on the application and are typically four or eight, evenly spaced around the signal contact 230. As with the signal contact 230, each plug 248 has an annular recess 252 for retention that fits into an annular protrusion 254. A knob 256 (eg, a knob 256) extends from the tabs 244, 246 into a recess 258 in the plate 89. Fig.12 ) helps to keep the sheets 244, 246 in place.

[0090] As mentioned above, conductive strip contacts may be used. Figures 13 to 16 In the embodiment of the present invention, the contact 270 is a strip of conductive material in the shape of a C. The contact may be formed by chemical etching, by stamping and forming, or by any other practicable means. The contact 270 is captured in the through-aperture 160 in the plate 89. In its resting state, the contact lead 272 extends outwardly from the plate 89, as shown in FIG. Fig.15 When the anchor block 88 is attached to the plate 89, the upper lead 272 is deformed toward the plate 89 and into the recess 276, as shown in FIG. Fig.16 As shown in FIG. 8 , electrical contact is provided to the signal conductor 22 through the signal contact 86 and point contact is provided to the anchor block 88 through the ground contact 87. When the assembly is connected to the feed-through block 30, the lower lead 274 is deformed toward the plate 89 and into the recess 278.

[0091] As indicated above, the signal travels through the flange 12 via the feedthrough 11 in the feedthrough block 30, shown in FIG. Figure 1 , 2 , 17 and 34. The first surface 38 of the block 30 is designed to withstand the first environment 1, and the second surface 40 of the block 30 is designed to withstand the second environment 2.

[0092] The feedthrough block 30 has a feedthrough 11 for each signal passed between the two environments 1, 2 through the flange 12. In order to accurately pass a controlled impedance signal, the feedthrough 11 requires at least three components: a signal coupling 61, a dielectric 53 surrounding the signal coupling 61, and a ground coupling 70 surrounding the dielectric 53.

[0093] The feedthrough 11 has two different configurations that differ based on the material from which the block 30 is constructed. If the block 30 is constructed of an electrically insulating material, then the block 30 itself can serve as the dielectric 53. If the block 30 is constructed of an electrically conductive material, then a separate dielectric 53 is required.

[0094] Feedthrough 11 without separate dielectric Fig.18 and 19The feedthrough 11 has a signal-through aperture 43 in the block 30, which extends between a first opening 44 in the first surface 38 of the block 30 and a second opening 45 in the second surface 40 of the block 30. Fig.19 As shown in FIG. 4 , the signal-through aperture 43 is generally circular, but may be other shapes.

[0095] The signal coupling 61 includes a signal link 62 extending through each signal aperture 43. The signal link 62 is a conductive wire or pin and can be made of any conductive material suitable for the application. Typically, the signal link 62 will be made of a copper alloy. In one configuration, the signal link 62 is made of beryllium copper plated with gold over nickel. If a non-magnetic signal link 62 is required, gold-plated beryllium copper can be used. The signal link 62 can also be made of a non-conductive material as long as the signal link 62 can conduct electricity. For example, the signal link 62 can be made of a non-conductive plastic or composite embedded or coated with a conductive material that renders the signal link 62 conductive.

[0096] The signal link 62 has a first end 65 at the block first surface 38 and a second end 66 at the block second surface 40. The signal link ends 65, 66 are contact points for the signal contacts 86 of the connectors 14, 16. Optionally, the signal ends 65, 66 are flush with the corresponding block surfaces 38, 40. Due to inaccuracies and tolerances in the manufacturing process, the signal link ends 65, 66 may not be exactly flush with the corresponding block surfaces 38, 40, that is, they may be slightly recessed into or protruding from the corresponding block surfaces 38, 40. Typically, the recess is no more than 0.0005 inches and the protrusion is no more than 0.001 inches, but may be as much as 0.05 inches. If the protrusion or recess is larger than allowable, the affected signal link end 65, 66 and the corresponding block surface 38, 40 may be polished and planarized by some mechanical means (e.g., by milling, grinding, or lapping) to ensure that the signal link end 65, 66 is at a known depth relative to the block surface 38, 40, in this case flush with the ground block face 20. The polished ends 65, 66 may also require precious metal plating to prevent them from oxidizing or otherwise degrading thereby inhibiting acceptable electrical connection.

[0097] This specification and claims use the term “flush” to indicate that the signal link ends 65 , 66 are substantially flush with, slightly recessed into, or slightly protruding from the corresponding block surfaces 38 , 40 by up to 0.05 inches.

[0098] The signal link 62 has a cross-sectional shape that allows for proper mechanical and electrical fit in the signal aperture 43. In the figure, both the signal aperture 43 and the signal link 62 are circular. However, the signal aperture 43 and the signal link 62 can be different cross-sectional shapes as long as the junction is structurally sound. For example, the signal aperture 43 can be circular and the signal link 62 can be octagonal.

[0099] Optionally, during installation or if the first environment 1 is at a higher pressure than the second environment 2, the signal link 62 and the signal aperture 43 are shaped to prevent the signal link 62 from being pushed through the signal aperture 43. Generally, the diameter of the signal link first end 65 is larger than the diameter of the signal aperture 43. Fig. 20 In one configuration illustrated in FIG. 4 , the signal link first end 65 has a head 63 having a larger diameter than the remainder of the signal link 62 and the signal aperture 43 . Fig.21 In another configuration illustrated in FIG. 4 , the signal link 62 is truncated cone-shaped rather than cylindrical. The signal aperture 43 is shaped to match so that when the signal link 62 is secured within the signal aperture 43, each end 65, 66 is at a corresponding block surface 38, 40. The present invention contemplates any other geometry that prevents the signal link 62 from being pushed through the signal aperture 43.

[0100] The ground coupling 70 is discussed below.

[0101] As indicated above, if the block 30 is composed of a conductive material, then only the dielectric 53 is required, such as Figures 22 to 25 A separate dielectric 53 may also be used if the block 30 is constructed of an electrically insulating material that does not have the necessary dielectric properties.

[0102] The feedthrough 11 has a spacer through-aperture 32 in the block 30 that extends between a first opening 34 in a first surface 38 of the block 30 and a second opening 36 in a second surface 40 of the block 30. Fig.23 and 25 As shown in FIG. 4 , the spacer through-aperture 32 is generally cylindrical but may be other shapes.

[0103] Within the spacer through-aperture 32 is a dielectric 53 in the form of a dielectric spacer 54. The spacer 54 has a cross-sectional shape that allows for proper mechanical and electrical fit in the spacer aperture 32. In the figure, both the spacer aperture 32 and the spacer 54 are circular. However, the spacer aperture 32 and the spacer 54 can be different cross-sectional shapes as long as the spacer 54 has the proper impedance and is structurally sound. For example, the spacer aperture 32 can be circular and the spacer 54 can be octagonal.

[0104] Optionally, during installation or if the first environment 1 is at a higher pressure than the second environment 2, the spacer aperture 32 and the spacer 54 are shaped to prevent the spacer 54 from being pushed through the spacer aperture 32. Generally, the first face 54 of the spacer 54 is larger than the second opening 36 of the spacer aperture 32. Fig.24 In one configuration illustrated in FIG. 1 , the spacer aperture 32 has a stepped diameter, such as at 48, to provide a shoulder 49. The spacer 54 abuts the shoulder 49 to prevent the spacer 54 from being within or pushed through the spacer aperture 32. In another configuration, the spacer 54 is truncated cone-shaped rather than cylindrical, similar to Fig.21 The spacer aperture 32 is shaped to match so that when the spacer 54 is secured within the spacer aperture 32, each end 56, 57 is properly positioned relative to the corresponding block surface 38, 40. The present invention contemplates any other geometry that prevents the spacer 54 from being pushed through the spacer aperture 32. .

[0105] The material from which the spacer 54 is made is selected depending on the application. The dielectric constant of the spacer 54 has a desired value (typically 50 ohms) to produce the desired impedance environment, but other impedances may be desired. The dielectric constant can range from 1.1 to 15 but is generally about 3 to 4. Typically, the spacer 54 is an engineered plastic (polyetheretherketone, PEEK), which is selected due to its dielectric constant (Dk) value and the resulting signal integrity performance. In one configuration, the Dk is 3.3, selected so that the feed-through impedance is 50 ohms. Different Dk values ​​may be used depending on the desired impedance, the diameter of the aperture 32, and the diameter of the signal link 62.

[0106] The spacer 54 has one or more signal through-apertures 43 extending between a first opening 44 in a first face 56 and a second opening 45 in a second face 57 of the spacer 54. For a coaxial cable 20, there is a single signal aperture 43 in the spacer 54 that is axially aligned. For a cable 20 having more than one signal conductor 22, the spacer 54 has a signal aperture 43 for each signal conductor 22, and the signal apertures 43 are proximally aligned and arranged for impedance matching, as described below.

[0107] A signal link 62 extends through each signal aperture 43. As described above, the signal link 62 is a conductive wire or pin.

[0108] As described above, the signal link 62 has a first end 65 at the block first surface 38 and a second end 66 at the block second surface 40. Optionally, the signal ends 65, 66 are flush with the corresponding block surfaces 38, 40.

[0109] As described above, during installation or if the first environment 1 is at a higher pressure than the second environment 2 , the signal link 62 is typically circular and may be shaped to prevent the signal link 62 from being pushed through the signal aperture 43 .

[0110] The remainder of this description is illustrated by a configuration having a spacer 54. It should be understood that the following description also applies to a configuration without a spacer 54 with appropriate modifications.

[0111] Optionally, the aperture 32, spacer 54 and signal link 62 are sized to provide impedance matching for the signal. Methods for doing this are well known in the art, including equations and software simulators, such as High Frequency Structure Simulator (HFSS). Key parameters include materials, Dk values ​​and dimensions.

[0112] In order for the feedthrough to provide accurate impedance matching, the dielectric 53 must be surrounded by the system ground plane. If the block 30 is conductive, no specific adjustments are required for the ground signal. The block 30 itself is the contact point for the ground contact 87 of the connector 14, 16.

[0113] The non-conductive block 30 must feed a ground signal between the surfaces 38, 40 via the ground coupling 70. This can be accomplished in a number of different ways.

[0114] In one configuration, the ground coupling 70 may include discrete conductive ground links 71 extending through ground apertures 72 in the block 30, such as Fig.18 and 28 The ground link 71 surrounds the signal link 62, such as Fig.19 and 29 , so that the ground signal surrounds the spacer 54 / signal link 62. The specific number of ground links 71 used to surround the signal link 62 and their distance from the signal link 62 will be determined by the parameters of the specific application, such as the desired impedance environment, the diameter of the signal link 62 and the spacer 54, and the materials from which the block 30 and the spacer 54 are constructed. The ground links 71 will generally be arranged equidistantly around the circle around the aperture 32. For example, if there are six ground links 71, they will be spaced 60° apart, such as in Fig.19 and 29 76 of them.

[0115] The ground link 71 is a conductive wire or pin and can be made of any conductive material suitable for the application. Typically, the ground link 71 will be made of a copper alloy. In one configuration, the ground link 71 is made of beryllium copper plated with gold over nickel. If a non-magnetic ground link 71 is desired, gold-plated beryllium copper can be used. The ground link 71 can also be made of a non-conductive material, as long as the ground link 71 can be conductive. For example, the ground link 71 can be made of a non-conductive plastic or composite embedded or coated with a conductive material that renders the ground link 71 conductive.

[0116] Optionally, during installation, if the first environment 1 is at a higher pressure than the second environment 2, the ground link 71 and the ground aperture 72 are shaped to prevent the ground link 71 from being pushed through the ground aperture 72. The same geometry described above with reference to the signal link 62 can be used. For example, each ground link first end 80 has a head 78 having a larger diameter than the rest of the ground link 71, such as Fig. 20 shown in.

[0117] In the case where the block 30 has a PCB structure or is composed of other dielectric materials, the ground link 71 can be a through hole 73 passing through the block 30, and the through hole 73 is plated (such as in Fig.30 The plated through hole 73 surrounds the signal link 62 as described above and generally connects the ground planes 79 on the two surfaces 38, 40, as shown in FIG. Fig.30 and 31 The plated through hole 73 is hermetically sealed by filling it with a potting material (eg, epoxy as at 75) or solder.

[0118] The ground link ends 80, 81 are contact points for ground contacts 87 of the connectors 14, 16. In the case of through-holes 73, the plating 74 may extend horizontally along the surfaces 38, 40 of the PCB to provide contact points 80, 81 for the ground contacts 87.

[0119] In another configuration of the ground coupling 70, the conductive ground fiber ferrule 64 is installed in the ground fiber ferrule through-aperture 84 in the block 30, and the spacer 54 is installed in the spacer aperture 32 in the ground fiber ferrule 64, so that the ground fiber ferrule 64 surrounds the spacer 54, as shown in FIG. Fig.32 The first end 82 of the ground fiber ferrule is flush with the first end 65 of the signal link 62, and the second end 83 of the ground fiber ferrule 64 is flush with the second end 66 of the signal link 62. The term "flush" is intended to have the same meaning as described above, wherein the fiber ferrule ends 82, 83 are actually flush with, slightly recessed into, or slightly protruding from the associated block surfaces 38, 40.

[0120] The fiber ferrule ends 82, 83 are contact points for the ground contacts 87 of the connectors 14, 16. The ground fiber ferrule 64 can be a different overall height than the spacer 54 mounted therein. Preferably, the fiber ferrule faces 82, 83 and the signal link ends 65, 66 protrude from the corresponding block surfaces 38, 40, thereby ensuring good compression contact with the signal contacts 86 and the ground contacts 89.

[0121] In another configuration of the ground coupling 70, the walls 41 of the spacer apertures 32 are coated with a conductive material. For example, if the block 30 is a PCB, the spacer apertures 32 may be plated through holes, such as in Fig.33 77 in the middle, where the plating 77 is electrically connected to ground. The coating 77 may cover the entire wall 41 or may only coat a portion of the wall 41, for example, as a band extending between the block surfaces 38, 40.

[0122] Optionally, Fig.33 The plating 77 in the spacer apertures 32 shown in FIG. 1 may extend horizontally along the surface of the PCB to provide contact points 78 for ground contacts 87 of the connectors 14 , 16 .

[0123] The signal link 62, ground coupling 70 and, when employed, the spacer 54 are mounted with a hermetic seal to hermetically separate the two environments 1, 2. The hermetic seal may be formed in one or more of several different ways.

[0124] First, the various components are press-fit into corresponding apertures, leaving no gaps between adjacent components. For example, the signal link 62 is press-fit into the signal aperture 43, leaving no gaps between the signal link 62 and the spacer 54 or the block 30. Optionally, the spacer 54 is composed of a slightly compressible material so that when the spacer 54 is installed in the spacer aperture 32, the spacer 54 expands against the spacer aperture wall 41 and against the signal link 62 to form an airtight seal.

[0125] exist Fig.24 In a second method of providing an airtight seal, illustrated in FIG, the spacer 54 is shorter than the spacer aperture 32, such that both faces 56, 57 of the spacer 54 are recessed from the corresponding block surfaces 38, 40, thereby leaving a first gap 58 between the spacer first face 56 and the block first surface 38, and a second gap 59 between the spacer second face 57 and the block second surface 40. Alternatively, only one face 57 is recessed from the block surface 40, leaving only one gap 59, and the opposing spacer face 56 extends to the corresponding block surface 38, as shown in FIG. Fig.26 Alternatively, only the other face 56 is recessed from the block surface 38, leaving only a gap 58, and the opposing spacer face 57 extends to the corresponding block surface 40, as shown. Fig. 27 .

[0126] One or both of the gaps 59, 58 (such as at 60) are potted to seal the spacer aperture 32 and surround the signal link 62, thereby creating a hermetic seal. A typical potting material is a two-part epoxy, but any material that provides the desired seal and is minimally affected by the environment may be used. The minimum depth of each gap 58, 59 that will provide a suitable hermetic seal depends on the environment and the potting material. In one configuration, the gap depth is approximately 0.02 inches and no less than 0.01 inches.

[0127] Most of the figures show the potting material 60 flush with the block surfaces 38, 40, but this is not required. The potting material 60 may be recessed into the gaps 58, 59, such as Fig. 27 Since the potting material 60 is initially liquid, it may form a meniscus 68 on its surface.

[0128] The plated through hole 73 is sealed with a potting material (such as in Fig.30 75 in the middle) or fill it with solder to make it hermetically sealed.

[0129] One method of potting involves applying a vacuum to one surface 40 of the block 30 and allowing the vacuum to pull the potting material 60 from the opposite side, thereby forcing the potting material 60 into the gaps 58 and all interfaces between components, such as between the signal link 62 and the spacer 54 or block 30, between the spacer 54 and the block 30, and between each ground link 71 and the block 30. The vacuum ensures that the potting material 60 is forced into all spaces that would provide a leakage path between the two environments 1, 2. Of course, the vacuum may be applied from the other surface 38 in the opposite direction.

[0130] In another method of potting, pressure is applied to the potting material at one surface 38 , 40 to push the potting material 60 into all spaces that would provide a leak path between the two environments 1 , 2 .

[0131] Both press-fit and potting methods can be used. For example, Fig.24 The shorter spacer 54 is sized to be press fit into the aperture 32 , and the signal link 62 is press fit into the signal aperture 43 , and then potting the gaps 58 , 59 .

[0132] The present invention contemplates that the flange 12 is a block 30, that is, the feed-through 11 extends through the flange 12 itself, such as Fig.34 and 35 .

[0133] Alternatively, the block 30 is a separate component that is hermetically sealed into the opening 50 in the flange 12. The block 30 may be similar to the connector body or the block 30 may be a printed circuit board. For the former, there may be more than one block 30 mounted in the flange 12, such as Fig.36 For the latter, typically a single PCB is mounted into the flange 12, such as Fig.37 , but more than one PCB may be used, such as Fig.36 The block 30 is mounted into the opening 50 by any suitable means, such as by screws or other mechanical means. The joint between the block 30 and the flange 12 may be potted to provide an airtight seal. Alternatively, a gasket may be used to provide an airtight seal.

[0134] The connectors 14, 16 are removably connected to the feed-through block 30. A typical connection mechanism is a through-hole jack 290, shown in FIG. Fig.38 The jack 290 extends through a hole 292 in the anchor block 88 and rotates into a threaded hole 294 in the feed-through block 30 .

[0135] Another embodiment is shown in Figures 39 to 41 The feed-through block 30 is an anchor block 88 for the connector 14. The anchor block 88 is mounted to the opening 50 in the flange 12 with an O-ring 210 to provide an airtight seal. Preferably, the connector 14 is mounted to be removable from the flange 12. A jack 212 extends through a hole 214 in the flange 12 and rotates into a threaded hole in the anchor block 88.

[0136] The cable holes 91 of the anchor block 88 are also hermetically sealed. If the cables 20 are permanently attached, then the attachment method (welding, crimping, potting with conductive adhesive, insert molding) provides a hermetic seal. If the cables 20 are removably attached in the cable holes 91, then after the cables 20 are installed, the cable holes 91 are potted to hermetically seal them.

[0137] The connectors 14, 16 are removably connected to each other with a single plate 89 attached to the removable connector 16. A typical connection mechanism is a through-hole jack 290. The jack 290 extends through a hole 292 in the anchor block 88 of the removable connector 16 and rotates into a threaded hole 296 in the anchor block 88 of the connector 14 mounted to the flange 12, as shown. Fig.41 .

[0138] The present invention allows for signals to be closer together than with SMA or SMP, thereby greatly increasing the overall channel density. Signal spacing can be 0.1 inches or less, resulting in a channel density greater than twice that of the current state of the art.

[0139] Materials and construction are picked for mechanical integrity due to environmental pressures and cycle life, minimizing leak rates as much as possible, ensuring desired controlled impedance and minimal outgassing. The thickness of the block 30 is driven by the mechanical strength of the block material. In the case where one environment is at a different pressure than the other, the block 30 must be thick enough to remain relatively flat over the area of ​​the surfaces 38, 40, e.g., + / - 0.01 inches, to ensure proper mating surfaces. Otherwise, the thickness of the block 30 is not critical.

[0140] Thus, a hermetically sealed controlled impedance feedthrough assembly has been shown and described. As certain changes could be made in the present disclosure without departing from the scope of the invention, it is intended that all matter described in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims

1. A hermetically sealed controlled impedance feedthrough assembly (10) located between a first environment (1) and a second environment (2), characterized in that: The feed-through assembly (10) comprises: a) a conductive block (30) having a first surface (38) designed to withstand the first environment (1) and a second surface (40) designed to withstand the second environment (2); b) at least one feedthrough (11) located in the block (30) and extending between the first surface (38) and the second surface (40), the feedthrough (11) comprising: 1) a spacer through-hole (32) extending between the first surface (38) and the second surface (40); 2) a dielectric spacer (54) located within the spacer through-hole (32) and having a first face (56) and a second face (57); 3) a signal-penetrating aperture (43) extending between the first face (56) and the second face (57); and 4) a rigid conductive signal link (62) located in the signal penetration aperture (43) and having a first end (65) located at the first surface (38) and a second end (66) located at the second surface (40); c) the feedthrough (11) is hermetically sealed between the first environment (1) and the second environment (2) by a press fit between the dielectric spacer (54) and the spacer through-aperture (32) and a press fit between the signal link (62) and the signal through-aperture (43).

2. The hermetically sealed controlled impedance feedthrough assembly (10) according to claim 1, characterized in that The dielectric spacer (54) is composed of a slightly compressible material.

3. The hermetically sealed controlled impedance feedthrough assembly (10) according to claim 1 or 2, characterized in that The signal link (62) and the signal through-aperture (43) are shaped to prevent the signal link (62) from being pushed through the signal through-aperture (43) in a direction, and wherein the dielectric spacer (54) and the spacer through-aperture (32) are shaped to prevent the dielectric spacer (54) from being pushed through the spacer through-aperture (32) in the direction.

4. The hermetically sealed controlled impedance feedthrough assembly (10) according to claim 3, characterized in that The first end (65) of the signal link (62) has a head (63) having a diameter that is larger than a diameter of the signal through-aperture (43).

5. The hermetically sealed controlled impedance feedthrough assembly (10) according to claim 3 or 4, characterized in that The spacer through-aperture (32) has a stepped diameter (48) creating a shoulder (49) such that the diameter of the first opening (34) is greater than the diameter of the second opening (36), and wherein the dielectric spacer (54) abuts the shoulder (49).

6. The hermetically sealed controlled impedance feedthrough assembly (10) according to claim 3, characterized in that The signal link (62) and the signal through-aperture (43) are matched truncated cone shapes.

7. The hermetically sealed controlled impedance feedthrough assembly (10) according to any one of claims 1 to 6, characterized in that It also includes a flange (12) separating the first environment (1) from the second environment (2), the block (30) mounted in the opening (50) in the flange (12), and hermetically sealing the joint between the block (30) and the flange (12).

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