Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
  • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
  • G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
  • G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
  • G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
  • G06K19/077—Constructional details, e.g. mounting of circuits in the carrier
  • G06K19/07749—Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
  • G06K19/07773—Antenna details
  • G06K19/07777—Antenna details the antenna being of the inductive type
  • G06K19/07779—Antenna details the antenna being of the inductive type the inductive antenna being a coil
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
  • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
  • G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
  • G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
  • G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
  • G06K19/077—Constructional details, e.g. mounting of circuits in the carrier
  • G06K19/07745—Mounting details of integrated circuit chips
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
  • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
  • G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
  • G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
  • G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
  • G06K19/077—Constructional details, e.g. mounting of circuits in the carrier
  • G06K19/07749—Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
  • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
  • G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
  • G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
  • G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
  • G06K19/077—Constructional details, e.g. mounting of circuits in the carrier
  • G06K19/07749—Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
  • G06K19/07773—Antenna details
  • G06K19/07777—Antenna details the antenna being of the inductive type
  • G06K19/07779—Antenna details the antenna being of the inductive type the inductive antenna being a coil
  • G06K19/07783—Antenna details the antenna being of the inductive type the inductive antenna being a coil the coil being planar
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/0001—Technical content checked by a classifier
  • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/22—Secondary treatment of printed circuits
  • H05K3/28—Applying non-metallic protective coatings
  • H05K3/284—Applying non-metallic protective coatings for encapsulating mounted components

Definitions

• This invention relates to a method of encapsulating components on a printed circuit
• plastic cards that is such cards which are carried by individuals and used for such purposes as recording or
• a previous proposal for fabricating plastic cards is as schematically illustrated in Figure 1.
• a printed circuit board comprising conductive tracks 6 has components 2 attached thereto, which components are potted in encapsulant 3.
• the encapsulant 3 is applied in such a quantity as to ensure that the components 2 are totally encapsulated.
• the thickness of this encapsulant 3 determines the thickness that the protective layers 4 and 5, typically of pvc material, have to be in order to accommodate the encapsulant.
• the present invention arose as a consequence of designing a card comprising such potted components which card was not to exceed the dimensions of a
• a method of encapsulating components on a printed circuit in which the encapsulating material is applied using a stencil.
• a corresponding number of apertures in a stencil enables a plurality of components to be encapsulated at the same time. It is particularly advantageous if the encapsulating material is screen printed, the stencil comprising the mask of the screen printing process.
• the printed circuit comprises a substrate layer with a number of tracks thereon, the substrate comprising a raised portion which forms a gasket for the encapsulant material.
• gasket in the context of this specification means a device which prevents the spread of a material and does not require that the gasket forms a seal between two members. The gasket enables the spread of the encapsulant to be restricted, thereby confining the predetermined amount of material deposited to a predetermined area further enabling the quantity of encapsulant deposited to be minimized by retaining it in the desired position.
• the method comprising depositing encapsulant within the area and subsequently compressing the encapsulant between the substrate and a capping layer until a meniscus of the encapsulant material comes into contact with the gasket.
• the capping layer comprises
• the material and preferably the encapsulant is compressed until the capping layer is restrained by
• This method is particularly advantageous for fabricating a plastic card wherein the thickness of the card is of importance, for dimensions in excess of the standard plastic card could prejudice the commercial success of such a card.
• Figure 1 schematically illustrates a previously proposed arrangement (not in accordance with the invention) of electrical components in a plastic card
• Figure 2 is a perspective view of a plastic card in accordance with the present invention.
• Figure 3 is a plan view of the card of Figure 2 having its top sheet 4 removed to reveal the printed circuit;
• Figure 4 is a cross-section through the card along the line I - 1 of Figure 3;
• FIGS 5 to 11 illustrate various stages in the production of the plastic card depicted in
• the card contains an integrated circuit. On Figure 2 it is possible to see edge portions of a substrate of the integrated circuit, exposed at a central part of each edge of the card.
• the integrated circuit communicates with interrogation units via an inductive link located at appropriate locations.
• the integrated circuit would normally contain a memory device and could be used for any number of purposes, for example recording banking transactions or recording zones of buildings etc to which entry has been gained by use of the card as an identity card.
• FIG. 3 there is illustrated a plan view through a section of the card 10 of
• FIG. 2 in the plane of the card. From this and the cross-section along line I - 1 illustrated in Figure 4 it can be seen that a printed circuit 11 comprises epoxy/glass substrate 12 and conductive tracks 13, a substantial portion of which form conductive loop 14. Shaded regions
• thermoset dielectric material 15 and 16 comprise of a thermoset dielectric material.
• the purpose of the region 15 is to insulate a silver conductor 17 from the inductive coil 14.
• dielectric layer 16 will be explained later.
• An integrated circuit and capacitive components are contained within a capsule-like element 19 which is separated by cut 18 from the rest of the substrate 12.
• the region 20 of the substrate 12 is lowered below the plane of the printed circuit
• the printed circuit 11 and element 19 are sandwiched between two outer sheets 23 and
• polyester which is coated on both sides with a thermally activated catalyst adhesive by which
• This polyester acts as a reinforcing layer preventing element 19 "breaking out" of the PVC layers 23 and 24.
• substrate sheet 12 of copper-clad epoxy/glass which is etched to form a large number of identical
• thermoset dielectric material indicated by the shaded regions 15, 16 which is cured in place.
• the function of circular part 16 is explained below.
• the linear part 15 serves as an insulator for the printed conductive link 17 for the inner end of a coil 14 defined by part of the printed circuit 13.
• a number of strips (not shown), each carrying printed patterns 25 (only one of which is illustrated), with
• the substrate carrying the etched patterns is placed on a bed of a screen printing machine (not shown) and a screen placed over it.
• a squeegee is then used to print a low ionic epoxy encapsulant adhesive material onto positions 27 as shown in Figure 6. This is a mixture of a
• Suitable materials are, for example, available
• An advantage of using epoxy adhesive is that if suitably selected it remains in its adhesive state for a sufficient time period which exceeds the maximum period during which the screen printing machine is not being operated. This avoids the need to clean down the equipment.
• the sheet substrate carrying the etched patterns and respective components positioned on it is then baked until the epoxy has gelled, i.e. set but not hardened. This takes place under
• Wire connections are then made between contacts on the individual components to appropriate parts of the printed copper circuitry. This is done by an ultrasonically assisted diffusion welding process. The sheet is then placed back in the screen printer with a different stencil in place. This stencil is much thicker, its thickness being selected so that the same epoxy encapsulant/adhesive now to be deposited over the components
• Figure 9 shows in cross-section the next stage of the process where a copper spacer 31
• encapsulant 30 deposited thereon is located on the sheet, 12.
• Previously placed on the copper sheet is each of the now separated strips 33, previously referred to, to form regions defined by printed patterns 25, from which regions reinforcing caps 22 will be formed.
• the spacer 31, with strips 33 located on it by means of pins (not shown for clarity), has been placed on top of the
• the whole arrangement is then pressed such that the patterns 25 are pressed into contact with the spacer 31 which is thus pressed closely down onto the circular part 16 of the dielectric material. It also presses the portions of the strip 33 defined by the patterns 25 onto the, still soft, epoxy encapsulant/adhesive thereby pulling the entire assembly down to the desired height.
• the encapsulant spreads out as shown in detail in Figure 10, but not as far as the edges of the spacer sheet. It is prevented from doing so by its meniscus acting against the inner edges of the copper pattern 25 and dielectric ring 16, which meniscus thereby defines the radius of the encapsulant.
• the printed circuit 1 with reinforced element 19 is now placed, as shown in Figure 11, between two outer sheets 37 and 38 of thermo plastics material in the pvc family with the inter ⁇
• the assembled sandwich is placed in a press where it is heated to cause lamination. During this stage the elements 19 imbed themselves in each of the sheets of thermo-plastic material in such a way as to tend to centralise themselves between opposite faces leaving the plane of the substrate sheet 1 on the central axis as shown in Figure 4.
• the press now opens and the assembly is removed to a cutting machine where the individual cards as illustrated in Figures 2 and 3 are cut out.
• each element could alternatively be formed on a separate part of the printed circuit which is subsequently connected to the main part of the printed circuit, the
• the elements would be formed by a process very similar to that
• the elements can be cut from the substrate having a limb extending from the element by which they are connected to the main portion of the printed circuit of a card by normal soldering of conductive tracks on the limb to tracks on the printed circuit or by similar techniques.
• the card shown in the illustration shows an electronic element connected to an inductive loop 14 in a contacless card.
• the electronic element could alternatively be connected by means of a limb to an electrical contact or other component of a card.

Landscapes

• Engineering & Computer Science (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Theoretical Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Credit Cards Or The Like (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=10738220

Family Applications (1)

Country Status (5)

Families Citing this family (5)

Family Cites Families (5)

• 1993
  • 1993-07-02 GB GB9313755A patent/GB9313755D0/en active Pending
• 1994
  • 1994-06-30 JP JP7503362A patent/JPH08512000A/ja active Pending
  • 1994-06-30 EP EP94918975A patent/EP0706694A1/de not_active Withdrawn
  • 1994-06-30 GB GB9413176A patent/GB2279817B/en not_active Expired - Fee Related
  • 1994-06-30 AU AU70064/94A patent/AU7006494A/en not_active Abandoned
  • 1994-06-30 WO PCT/GB1994/001418 patent/WO1995001613A1/en not_active Application Discontinuation

Non-Patent Citations (1)

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