WO2022225675A1 - Contact de rouleau à variation de résistance de contact réduite - Google Patents

Contact de rouleau à variation de résistance de contact réduite Download PDF

Info

Publication number
WO2022225675A1
WO2022225675A1 PCT/US2022/023019 US2022023019W WO2022225675A1 WO 2022225675 A1 WO2022225675 A1 WO 2022225675A1 US 2022023019 W US2022023019 W US 2022023019W WO 2022225675 A1 WO2022225675 A1 WO 2022225675A1
Authority
WO
WIPO (PCT)
Prior art keywords
contact assembly
electrically conductive
roller contact
conductive material
axle
Prior art date
Application number
PCT/US2022/023019
Other languages
English (en)
Inventor
Douglas Garcia
Original Assignee
Electro Scientific Industries, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Electro Scientific Industries, Inc. filed Critical Electro Scientific Industries, Inc.
Publication of WO2022225675A1 publication Critical patent/WO2022225675A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
    • G01R31/64—Testing of capacitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
    • H01R13/02—Contact members
    • H01R13/03—Contact members characterised by the material, e.g. plating, or coating materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R2201/00—Connectors or connections adapted for particular applications
    • H01R2201/20—Connectors or connections adapted for particular applications for testing or measuring purposes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R39/00—Rotary current collectors, distributors or interrupters
    • H01R39/64—Devices for uninterrupted current collection
    • H01R39/643—Devices for uninterrupted current collection through ball or roller bearing

Definitions

  • Embodiments of the present invention relate to circuitry and, more particularly, to circuitry for electrical measurement systems.
  • Capacitors which store electric charge, are one of the basic building blocks of electronic circuits.
  • a capacitor comprises two conductive surfaces separated from one another by a small distance, wherein a nonconductive dielectric material lies between the conductive surfaces.
  • the capacitance C of such an arrangement is proportional to KA/d, wherein K is the dielectric constant of the dielectric material, A is the area of the opposing conducting surfaces, and d is the distance between the conducting surfaces.
  • a multilayer ceramic capacitor (MLCC) is a type of capacitor made of alternating layers of electrodes and dielectric material (i.e., a ceramic material). MLCCs are commonly used in electronic circuits (e.g., as bypass capacitors, in filters, op-amp circuits, and the like).
  • MLCC manufacturers typically specify their capacitors in terms of parameters such as capacitance (C), dissipation factor (DF), insulation resistance (IR), and the like. MLCCs are typically tested to ensure that they fall within acceptable limits before they are sold or used. MLCCs can be tested in a variety of machines. Typically, such machines (also referred to herein as “MLCC testers”) carry an MLCC through a series of test stations for performing various functions (e.g., testing, pre-soak, pre-charge, etc.).
  • FIG. 1 illustrates a partial perspective view of a conventional MLCC tester.
  • the MLCC tester 100 includes a carrier plate 102, an upper test head assembly 104, and a lower test head assembly 106.
  • the upper test head assembly 104 includes a support 108 and a plurality of upper contact assemblies 110 (i.e., each provided as a roller contact assembly) coupled to the support 108.
  • the lower test head assembly 106 includes a support 112 and a plurality of lower contacts 114 embedded within the support 112.
  • the carrier plate 102 has a plurality of through-holes (also referred to herein as “pockets”) formed therein, each of which can accommodate an MLCC 108 to be tested. As shown in FIG. 1, the carrier plate 102 is moveable so as to convey the MLCCs 104 (e.g., along a direction indicated by arrow 102a) to and from various test stations. In particular, the carrier plate 102 is moveable so as to convey each MLCC 104 into, and out of, a space between an upper contact assembly 110 and a corresponding lower contact 114 of a test station.
  • the carrier plate 102 is moveable so as to convey each MLCC 104 into, and out of, a space between an upper contact assembly 110 and a corresponding lower contact 114 of a test station.
  • one electrode of the MLCC 104 slides onto the lower contact 114 while the other of the electrodes (e.g., an upper-illustrated contact, as illustrated in FIG. 1) rotates a contact wheel of the upper contact assembly 110 (e.g., about a stationary axle of the of the upper contact assembly 110).
  • the contact wheel is supported by the axle and, when the contact wheel rotates relative to the axle, an inner surface of the contact wheel slides over the outer diameter of the axle.
  • the lower electrode of the MLCC 104 is electrically contacted to the lower contact 114 and the upper electrode of the MLCC 104 is electrically contacted to the contact wheel of the upper contact assembly 110.
  • the carrier plate 102 is kept stationary and the MLCC 104 is subjected to a test.
  • a voltage from test circuitry 116 is applied to lower electrodes of the MLCC 104 through the lower contact 114 and the response of the MLCC 104 to the applied voltage is measured by the test circuitry 116 through an electrically conductive signal path extending from the contact wheel of the upper contact assembly 110 to the test circuitry 116.
  • the contact wheel of the upper contact assembly 110 is electrically coupled to the test circuitry through other components (e.g., the axle and an assembly body) of the upper contact assembly 110.
  • the MLCC 104 is conveyed out of the test station. As the MLCC 104 is conveyed out of the test station, the lower electrode of the MLCC 104 slides off of the lower contact 114 while the upper electrodes of the MLCC 104 rotates a contact wheel of the upper contact assembly 110.
  • the contact wheel and axle are formed of electrically conductive materials.
  • the axle is electrically connected to another electrically conductive structure (e.g., the assembly body) of the upper contact assembly 110 that is in electrical communication with the test circuitry 116.
  • the contact wheel is formed of coin silver and the axle is formed of silver graphite material.
  • the silver at the inner surface of the contact wheel can oxidize, and graphite at the outer diameter of the axle can become dislodged as debris. Friction polymerization can also occur at the interface between the surfaces of the contact wheel and the axle.
  • oxidation products e.g., oxidized silver
  • debris e.g., graphite debris
  • friction polymerization products between the contact wheel and the axle can cause the electrical contact resistance therebetween to vary (typically, get larger).
  • Increased electrical contact resistance at the contact wheel/axle interface degrades the performance of the MLCC tester.
  • the DF measurement of the MLCC tester is particularly sensitive to increased contact resistance, which can add an artificial error to the measurement of a test result at a DF test station.
  • an MLCC that is actually good can fail a given test criteria; causing the MLCC to be unnecessarily thrown out or re-tested.
  • a roller contact assembly includes a contact wheel having a bore defined therein and a contact surface located radially outward from the bore, and an axle extending through the bore.
  • the surface of the bore is formed of a first electrically conductive material and the contact surface is formed of a second electrically conductive material different from the first electrically conductive material.
  • An exterior surface of the axle is formed of a third electrically conductive material different from the second electrically conductive material.
  • FIG. 1 is a perspective view partially illustrating an MLCC tester according to the related art.
  • FIGS. 2 and 3 are perspective views, shown from different angles, of a roller contact assembly according to some embodiments of the present invention.
  • FIG. 2A is partial cross-sectional perspective view, taken along line IIA-IIA’ as shown in FIG. 2, of the assembly body and contact wheel of the roller contact assembly shown in FIG. 2.
  • FIG. 2B is partial cross-sectional perspective view, taken along line IIB-IIB’ as shown in FIG. 2, of the assembly body of the roller contact assembly shown in FIG. 2.
  • a range of values when recited, includes both the upper and lower limits of the range, as well as any sub-ranges therebetween.
  • terms such as “first,” “second,” etc. are only used to distinguish one element from another. For example, one node could be termed a “first node” and similarly, another node could be termed a “second node”, or vice versa.
  • the term “about,” “thereabout,” etc. means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art.
  • Spatially relative terms such as “below,” “beneath,” “lower,” “above,” and “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element or feature, as illustrated in the FIGS. It should be recognized that the spatially relative terms are intended to encompass different orientations in addition to the orientation depicted in the FIGS.
  • FIGS For example, if an object in the FIGS is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features.
  • the exemplary term “below” can encompass both an orientation of above and below.
  • An object may be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may be interpreted accordingly.
  • a roller contact assembly is provided which significantly reduce or eliminate the accumulation of oxidation products, debris and friction polymerization products (or deleterious effects resulting therefrom).
  • a roller contact assembly 200 may include a bracket 202, a contact wheel 204, an axle 206 and a plate 208.
  • the axle 208 is inserted through a central bore of the contact wheel 204, and is held in place between the bracket 202 and the plate 208.
  • the contact wheel 204 is rotatable about the axle 206 (relative to the bracket 202).
  • the bracket 202, contact wheel 204 and axle 206 are electrically connected to each other.
  • materials used in forming the contact wheel 204 and the axle 206 are selected to significantly reduce or eliminate the accumulation of oxidation products, as well as debris and friction polymerization products (or deleterious effects resulting therefrom), thereby reducing the evolution of increased contact resistance at the contact wheel/axle interface which can degrade the performance of the MLCC tester.
  • the bracket 202 includes a main body 210, a pair of first walls 212a and 212b extending from the main body 210, and a pair of second walls 214a and 214b each extending from a respective wall of the pair of first walls 212a or 212b.
  • the main body 210, first walls 212a and 212b, and second walls 214a and 214b of the bracket 202 are illustrated as an integral, monolithic body, it will be appreciated that bracket 202 may be formed as a plurality of separate structures mechanically coupled together by any known or suitable technique.
  • the bracket 202 is formed of an electrically conductive material (e.g., to permit transmission of electricity from the axle 206 to test circuitry, as will be discussed in greater detail below).
  • lateral edges of the pair of first walls 212a and 212b define a well 216, through which the contact wheel 204 can rotate.
  • terminal edges of the pair of first walls 212a and 212b are configured to mate with or engage an outer surface of the axle 206.
  • the terminal edges of the pair of first walls 212a and 212b define a concave arc having a radius that generally corresponds to the radius of the axle 206.
  • lateral edges of the pair of second walls 214a and 214b are offset from one another along an axial direction of the axle 206 (e.g., parallel to the Y-axis, as illustrated in FIGS. 2A and 3). Further, the lateral edges of the pair of second walls 214a and 214b overlap the corresponding ends of the axle 206, preventing movement of the axle 206 along the axial direction (Y-axis).
  • the contact wheel 204 has a bore defined therein, and a contact surface located radially outward from the bore.
  • the axle 206 extends through the bore. Radial dimensions of the axle 206 and bore are selected such that a clearance of 0.08 mm (or thereabout) or less exists between the exterior surface of the axle 206 and the surface of the bore.
  • the bore has a width (e.g., as measured along the Y-axis shown in FIGS. 2A and 3), in a range between 1.0 mm (or thereabout) and 2.8 mm (or thereabout).
  • the contact wheel 204 is formed of a contact roller 218 and a contact sleeve 220, wherein the contact roller 218 defines the contact surface of the contact wheel 204 and the contact sleeve 220 defines the bore.
  • the thickness of the contact sleeve 220 is in a range between 0.1 mm (or thereabout) and 0.3 mm (or thereabout).
  • the surface of the bore (and, thus, the contact sleeve 220) is formed of a first electrically conductive material.
  • the contact surface (and, thus, the contact roller 218) is formed of a second electrically conductive material different from the first electrically conductive material.
  • the first electrically conductive material is an alloy including at least 50 wt% gold and at least 20 wt% copper.
  • the alloy of the first electrically conductive material may, optionally, further include silver, zinc (up to 5 wt%), nickel (up to 2 wt%), at least one selected from the group consisting of platinum, palladium, rhodium and iridium (up to 5 wt%, in total), or the like or any combination thereof.
  • the composition of the second electrically conductive material includes an alloy containing at least 50 wt% silver.
  • the contact sleeve 220 can be attached to the contact roller 218 by any suitable technique.
  • the contact sleeve 220 may be provided as a cylindrical tube that is inserted into a chamfered, central bore extending through the contact roller 218, and then ends of the tube can be flared or swaged onto the chamfers at each side of the central bore extending through the contact roller 218. See, e.g., FIG. 2A.
  • the cylindrical tube is inserted into the central bore of the contact roller 218 and then expanded against the bore surface of the contact roller 218 (the predominantly-gold contact sleeve 220 is malleable).
  • the contact sleeve 220 can be bonded to the contact roller 218 (e.g., using a silver or copper filler conductive adhesive, or may be soldered to the contact roller 218).
  • the surface of the bore (and, thus, the surface of the contact sleeve 220 defining the bore) has a Vickers hardness number (VHN) in a range from 135 to 150. Vickers hardness can be measured by any recognized standard, including ASTM E384-17 or ISO 6507- 1:2018.
  • the contact sleeve 220 can be provided with the desired hardness as discussed above by first forming the contact sleeve 220 (e.g., with the desired composition of the first electrically conductive material and to the desired dimensions) followed by an annealing treatment.
  • the annealing treatment includes: 1) coating the contact sleeve 220 with a thin oxidation prevention film (e.g., a film of boric acid); 2) heating the coated contact sleeve 220 such that the contact sleeve glows due to incandescence and then rapidly cooled or quenched (e.g., in water); and 3) pickling the contact sleeve 220 (e.g., placing the contact sleeve 220 in a heated water bath containing a mild acid cleaner) to remove the oxidation prevention film.
  • the contact sleeve 220 is not annealed.
  • the axle 206 is formed of a thin, tubular cylinder.
  • the interior 222 of the cylinder may be hollow, or may be filled with a support material such as epoxy.
  • the axle 206 may be formed of a third electrically conductive material that is the same as or different from the first electrically conductive material.
  • the third electrically conductive material is an alloy including at least 50 wt% gold and at least 20 wt% copper.
  • the alloy of the third electrically conductive material may, optionally, further include silver, zinc (up to 5 wt%), nickel (up to 2 wt%), at least one selected from the group consisting of platinum, palladium, rhodium and iridium (up to 5 wt%, in total), or the like or any combination thereof.
  • the plate 208 may be coupled to the body 210 (e.g., by a screw, as illustrated in FIGS. 2, 2B and 3) and include a pair of arms 224 extending to opposite ends of the axle 206 (e.g., so as to be spaced apart from each other along the Y-axis, as illustrated in FIGS. 2B and 3).
  • the arms 224 are sufficiently rigid such that, when the plate 208 is coupled to the body 210, the arms 224 bias the axle 206 against the terminal edges of the pair of first walls 212a and 212b.
  • the axle 206 can be held between the body 210 and the plate 208.
  • the plate 208 can be formed of an electrically conductive material (e.g., to permit transmission of electricity from the axle 206 to test circuitry, as will be discussed in greater detail below).
  • roller contact assemblies such as roller contact assembly 200
  • roller contact assembly 200 may be used to replace the upper contact assemblies 110 connected to the support 108, as described above with respect to FIG. 1.
  • the contact sleeve 220 and axle 206 are formed of the first and third electrically conductive materials as described above, the generation and accumulation of debris and oxidation and friction polymerization products at the interface between the contact wheel 204 and the axle 206 (and deleterious effects resulting therefrom) can be significantly reduced (i.e., relative to the rate with which such products are generated at the coin silver/silver graphite material interface of the contact wheel and axle of the upper contact roller assembly 110).
  • composition of the first and third electrically conductive materials will be selected on the basis of the hardness or thickness of oxide materials generated over the lifetime of the roller contact assembly 200, as well as the propensity of the materials to create friction polymerization products at the interface between the contact wheel 204 and the axle 206 (e.g., when the contact wheel 204 rotates about the axle 206). Accordingly, the evolution of increased contact resistance at the contact wheel/axle interface of the roller contact assembly 200 can be significantly retarded.
  • the contact wheel 204 rotates about the axle 206, some gold and copper material from the contact sleeve 220 will transfer onto the axle 206 and vice-versa; gold has a relatively high electrical conductivity and high resistance to oxidation, so the contribution of gold to increased contact resistance over time is relatively small.
  • Copper tends to oxidize relatively quickly, especially because the copper that is transferred between the contact sleeve 220 and the axle 206 is the form of very fine particulates and the heat generated during rotation of the contact wheel 204 accelerates oxidation.
  • the oxidized copper does not have a strong propensity to re- bond (or otherwise bond strongly) to the interface surfaces of the contact sleeve 220 and axle 206.
  • oxidized copper can be easily removed from the interface surfaces of the contact sleeve 220 and axle 206 using widely-available cleaning agents (e.g., in the jewelry industry) known to clean copper surfaces (i.e., remove copper oxide).
  • the rolling resistance of the contact wheel 204 can be kept very low, which is helpful in preventing scuffing or marking or other damage to the upper electrode (which is formed of a relatively soft material such as tin) of the MLCC 104 as the MLCC 104 moves into and out of a test station.
  • the contact wheel 204 will rotate at a rate between 2,000 and 11,000 RPM during short intermittent intervals in a range between 10 and 30 milliseconds, at a frequency in a range between 1 and 44 Hz. Forces transferred from the contact wheel 204 to the axle 206 during operation are in a range between 2 and 200 gram-force.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Contacts (AREA)
  • Tires In General (AREA)

Abstract

Ensemble de contact de rouleau comprenant une roue de contact ayant un alésage défini en son sein et une surface de contact située radialement vers l'extérieur à partir de l'alésage, et un axe s'étendant à travers l'alésage. La surface de l'alésage est formée d'un premier matériau électroconducteur et la surface de contact est formée d'un deuxième matériau électroconducteur différent du premier matériau électroconducteur. Une surface extérieure de l'axe est formée d'un troisième matériau électroconducteur différent du deuxième matériau électroconducteur.
PCT/US2022/023019 2021-04-22 2022-04-01 Contact de rouleau à variation de résistance de contact réduite WO2022225675A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US202163178108P 2021-04-22 2021-04-22
US63/178,108 2021-04-22

Publications (1)

Publication Number Publication Date
WO2022225675A1 true WO2022225675A1 (fr) 2022-10-27

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PCT/US2022/023019 WO2022225675A1 (fr) 2021-04-22 2022-04-01 Contact de rouleau à variation de résistance de contact réduite

Country Status (2)

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TW (1) TW202249561A (fr)
WO (1) WO2022225675A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994000769A1 (fr) * 1992-06-26 1994-01-06 Monsanto Company Appareil de mesure de la resistivite electrique superficielle d'une bande en mouvement
US6040705A (en) * 1997-08-20 2000-03-21 Electro Scientific Industries, Inc. Rolling electrical contactor
US6714028B2 (en) * 2001-11-14 2004-03-30 Electro Scientific Industries, Inc. Roller contact with conductive brushes
US7839138B2 (en) * 2007-01-29 2010-11-23 Electro Scientific Industries, Inc. Adjustable force electrical contactor
JP2013053936A (ja) * 2011-09-05 2013-03-21 Tokyo Weld Co Ltd ワーク測定装置、ワーク搬送テーブル、ワーク測定方法及び電子部品の製造方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994000769A1 (fr) * 1992-06-26 1994-01-06 Monsanto Company Appareil de mesure de la resistivite electrique superficielle d'une bande en mouvement
US6040705A (en) * 1997-08-20 2000-03-21 Electro Scientific Industries, Inc. Rolling electrical contactor
US6714028B2 (en) * 2001-11-14 2004-03-30 Electro Scientific Industries, Inc. Roller contact with conductive brushes
US7839138B2 (en) * 2007-01-29 2010-11-23 Electro Scientific Industries, Inc. Adjustable force electrical contactor
JP2013053936A (ja) * 2011-09-05 2013-03-21 Tokyo Weld Co Ltd ワーク測定装置、ワーク搬送テーブル、ワーク測定方法及び電子部品の製造方法

Also Published As

Publication number Publication date
TW202249561A (zh) 2022-12-16

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