Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/12—Supports; Mounting means
  • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
  • H01Q1/2208—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems
  • H01Q1/2225—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• • 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
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/12—Supports; Mounting means
  • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
  • H01Q1/38—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith formed by a conductive layer on an insulating support
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
  • H01Q9/04—Resonant antennas
  • H01Q9/16—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole
  • H01Q9/26—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength

Definitions

• the present invention relates to contactless transmission and reception systems, and more particularly to a high inductance coupling antenna used in particular in contactless smart cards.
• contactless transmission and reception systems are widely used today in many applications.
• One of these applications is the contactless smart card, which is a system that is increasingly used in different sectors.
• contactless smart cards have been developed by all motorway companies in order to offer subscriptions to their users and to facilitate payment at toll stations. They have also been developed as a means of payment. This is the case for example of the electronic purse.
• Many companies have also developed means of identifying their personnel by contactless smart cards.
• the exchange of information between a contactless card and the associated reading device is carried out by remote electromagnetic coupling between an antenna housed in the contactless card and a second antenna located in the reader.
• the card is equipped with a chip comprising a memory area and a microprocessor, which is connected to the antenna.
• This chip contains an input capacitance obtained by means of capacitors inserted in the chip.
• the antenna and the chip are generally on a neutral flat support. The optimal functioning of the antenna-chip coupling which must be non-resistive is obtained when the following circuit resonance law is respected:
• LCCû 2 1 (1) in which L represents the inductance of the antenna, C represents the input capacity and ⁇ the pulsation equal to 2 ⁇ f, in which f represents the normalized frequency (for example at 13.56 MHz).
• f represents the normalized frequency (for example at 13.56 MHz).
• contactless electronic cards necessarily involves reducing the production costs of the chips used in these cards.
• the founders are led more and more to decrease the number of capacitors integrated in these and thus to reduce the capacity of the circuit. They can thus produce chips of smaller dimensions.
• the inductance L of the antenna In order to comply with the LC ⁇ 2 1 law and obtain optimal coupling, the inductance L of the antenna must be increased to compensate for the drop in the value of the chip's input capacity.
• the inductance In the case of antennas produced by chemical etching of copper or aluminum, in the form of turns on a plastic dielectric support, the inductance is generally increased by increasing the number of turns.
• this solution generates several significant drawbacks. Indeed, any electric circuit having a resistance, the increase in the number of turns, which in fact corresponds to an elongation of the circuit, leads to a strong increase in the value of this resistance. This considerably affects the performance of the antenna and therefore of the card. Indeed, the reading distance of the card is greatly reduced.
• the width of the copper tracks must be reduced. This has the effect of increasing the resistance of the antenna, and especially the reliability of the cards is deteriorated because the risk of cuts antenna turns during hot pressure lamination of card bodies is more important.
• the unit cost of the etched antenna increases significantly.
• the cost reduction obtained by founders with chips having a lower input capacity is canceled out by this additional cost of the antennas.
• the manufacture and use of cards is therefore not more profitable.
• the object of the invention is to overcome these drawbacks by providing an antenna with a high inductance making it possible to obtain a high-performance card, the reliability of which is proven and the production cost and therefore the cost price are significantly lower than the smart cards currently on the market.
• the invention relates to a coupling antenna constituted by a plurality of turns in series situated on a flat support constituted by an insulating dielectric substrate.
• This antenna comprises one or more sets of at least one turn located on said planar support, mounted in series, at least one of the sets being constituted by at least two turns in series superimposed along an axis perpendicular to the plane of the support and separated by a insulating strip of dielectric ink, which makes it possible to obtain a high inductance value.
• the coupling antenna comprises one or more assemblies, mounted in series, of at least one turn of screen-printed ink on the flat support, at least one of the assemblies being constituted by at least two turns series of screen-printed ink superimposed on an axis perpendicular to the plane of the support and separated by an insulating strip of dielectric ink also screen-printed on the support.
• Another aspect of the invention is the method of manufacturing the coupling antenna consisting in: screen printing a turn of one or more assemblies, by depositing conductive ink on a face of a flat support consisting of an insulating dielectric substrate, screen printing an insulating strip superimposed on the screen printing of the coil of at least one assembly, by depositing dielectric ink, allowing the coil to be covered and leaving visible the connection pads of the antenna and the connection zones of the superimposed turns,
• the instantaneous performance of a screen-printed antenna comprising less than three turns is at least comparable to that of an engraved antenna and even superior after the various mechanical and aging tests (humid heat).
• the increase in the number of turns is detrimental to the screen-printed antenna because the electrical properties deteriorate very quickly beyond three turns (loss of electrical conductivity and inductance capping).
• the inventive process overcomes this technological impasse by proposing a screen-printed antenna compatible with low-capacity chips.
• Figure 1 shows the electrical diagram of a contactless memory card.
• FIG. 2 represents the coupling antenna according to a particular embodiment, at the end of the first step of this embodiment.
• FIG. 3 represents the coupling antenna according to the invention, at the end of the second step of this embodiment.
• FIG. 4 represents the coupling antenna according to the invention, at the end of the last step of this embodiment.
• the electrical circuit of the card 1 is subdivided into two components: the antenna and the chip.
• Chip 2 has an internal capacitance Cs 4 obtained by means of capacitors placed in the chip. It also includes an electronic part 6 corresponding to the memory area and to the processor.
• the chip 2 is connected to the antenna 8 via the circuit 1.
• the antenna 8 has a resistance Rs 10 which is the cause of a power lost in the circuit.
• the antenna also has its own Ls 12 inductance.
• Figures 2, 3 and 4 show the antenna after the three main stages of the manufacturing process. It is an antenna with a set of two superimposed turns. The same method can be used to make an antenna with several sets of at least one turn and at least one of the sets of which consists of at least two superposed turns.
• the turn 16 of conductive ink was screen printed on the flat support 14 consisting of an insulating dielectric substrate, as illustrated in FIG. 2.
• This dielectric substrate is made of plastic, paper or glass fabric impregnated with thermosetting resin or crosslinkable by UV radiation
• the plastic material used is for example polyvinyl chloride (PVC), polyester (PET, PETG), polycarbonate
• the conductive ink used contains polymers and is loaded with conductive elements which may be metals. Preferably, the ink used is loaded with silver. However, it can also be loaded with copper or carbon. The ink contains between 50 and 70% silver in the form of beads or strips. The polymers used are polyesters or acrylic resins. The ink also contains a solvent which acts as a vehicle. According to a particular embodiment, the solvent used is a glycol ether.
• the coil 16 follows the contours of the support. One of its ends is in contact with one of the connection pads 18 making it possible to connect the antenna to an electrical or electronic component such as a chip. The other end of the turn is free so that it can be connected to the second turn.
• Figure 3 shows the antenna after the second stage of its manufacturing process.
• a second screen printing is carried out.
• This second screen printing corresponds to the deposition of at least two layers of dielectric ink constituting the insulating strip 20 between the two turns.
• each layer has a thickness of 25 microns.
• This ink contains polymers and cross-links when it is subjected to UV radiation.
• the polymers can be acrylate resins or unsaturated polyesters.
• this ink does not contain any solvent.
• the polymers contained in the ink will crosslink when the ink is subjected to UV radiation. This crosslinking causes the ink to harden.
• the geometry of the antenna is very stable and above all the thickness of this insulating strip and therefore the distance between the two turns does not vary, which allows the antenna to maintain its optimal operating quality.
• This ink in order to be sufficiently insulating, must have the highest possible relative permittivity.
• the value of the permittivity is generally greater than 3.
• the permittivity of the ink used for screen printing the insulating strip is 3.9.
• at least two layers of ink are required. Indeed, after crosslinking, the ink layer has a high porosity which prevents it from having a high insulating power.
• two successive and superimposed layers are screen printed and constitute a strip with a high insulating power.
• This strip is superimposed on the coil 16 and completely covers the latter and in particular the end which is in contact with one of the connection pads 18 of the antenna, with the exception of the second end 17 which is left free in order to be able to connect the two turns together.
• Figure 4 shows the antenna finished after the third and last step of its manufacturing process.
• a third screen printing corresponding to the turn 22 was carried out. It is superimposed on the turn 16 of the first set and on the insulating strip 20 which is between the two turns, along an axis which is perpendicular to the plane of the support 14. One end of this turn 22 is connected to the free end 17 of the first turn 16. The second end of the turn 22 is connected to the second connection pad 24 of the antenna.
• the antenna consists of two turns in series, which are in two different planes and parallel to each other, each being parallel to the support 14.
• an antenna of this type is called antenna in " Z ".
• the antennas may include one or more sets of a single turn and one or more sets of several turns mounted in series. Each set of several turns being made up of turns in superimposed series, the number and the diameter of superimposed turns varying from one set to the other.
• the coupling antenna according to the invention can be used in particular in contactless smart cards.
• These cards consist of a flat support carrying at least one high inductance coupling antenna connected to at least one chip, also on the flat support, having a low internal capacity.
• the flat support is inserted between two card bodies, said card bodies being fixed on each side of said flat support in order to stiffen it.
• These card bodies can be made of plastic.
• the plastic used can be polyvinyl chloride (PVC), polyester (PET, PETG), polycarbonate (PC), or acrylonitrile-butadiene-styrene (ABS).

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• 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)
• Details Of Aerials (AREA)
• Support Of Aerials (AREA)
• Credit Cards Or The Like (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=9551739

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• 1999
  • 1999-10-28 FR FR9913851A patent/FR2800518B1/fr not_active Expired - Fee Related
• 2000
  • 2000-10-26 NZ NZ512524A patent/NZ512524A/xx unknown
  • 2000-10-26 TR TR2001/01904T patent/TR200101904T1/xx unknown
  • 2000-10-26 IL IL14375200A patent/IL143752A/xx not_active IP Right Cessation
  • 2000-10-26 JP JP2001533582A patent/JP2003513492A/ja active Pending
  • 2000-10-26 CN CNB008024480A patent/CN1223043C/zh not_active Expired - Fee Related
  • 2000-10-26 BR BR0007267-2A patent/BR0007267A/pt not_active IP Right Cessation
  • 2000-10-26 WO PCT/FR2000/002983 patent/WO2001031731A1/fr not_active Application Discontinuation
  • 2000-10-26 MX MXPA01006592A patent/MXPA01006592A/es active IP Right Grant
  • 2000-10-26 KR KR1020017007440A patent/KR20010101217A/ko not_active Application Discontinuation
  • 2000-10-26 US US09/868,776 patent/US6575374B1/en not_active Expired - Fee Related
  • 2000-10-26 ID IDW00200101397A patent/ID29351A/id unknown
  • 2000-10-26 EP EP00971513A patent/EP1142058A1/fr not_active Withdrawn
  • 2000-10-26 RU RU2001121146/09A patent/RU2236726C2/ru not_active IP Right Cessation
  • 2000-10-26 CA CA002356378A patent/CA2356378A1/fr not_active Abandoned
  • 2000-10-26 AU AU10355/01A patent/AU777064B2/en not_active Ceased
• 2001
  • 2001-05-03 TW TW090110624A patent/TW541763B/zh not_active IP Right Cessation
  • 2001-06-13 ZA ZA200104798A patent/ZA200104798B/en unknown
  • 2001-06-19 NO NO20013047A patent/NO20013047D0/no unknown
• 2002
  • 2002-08-13 HK HK02105912.2A patent/HK1044418B/zh not_active IP Right Cessation

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