Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B5/00—Near-field transmission systems, e.g. inductive or capacitive transmission systems
  • H04B5/20—Near-field transmission systems, e.g. inductive or capacitive transmission systems characterised by the transmission technique; characterised by the transmission medium
  • H04B5/24—Inductive coupling
  • H04B5/26—Inductive coupling using coils
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
  • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
  • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
  • G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
  • G06K7/10316—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves using at least one antenna particularly designed for interrogating the wireless record carriers
  • G06K7/10336—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves using at least one antenna particularly designed for interrogating the wireless record carriers the antenna being of the near field type, inductive coil
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
  • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
  • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
  • G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
  • G06K7/10316—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves using at least one antenna particularly designed for interrogating the wireless record carriers
  • G06K7/10346—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves using at least one antenna particularly designed for interrogating the wireless record carriers the antenna being of the far field type, e.g. HF types or dipoles

Definitions

• the invention relates to the field of contactless electronic labels which are used to identify products by subjecting them to the electromagnetic field of a read or read / write device, the magnetic component of the electromagnetic field being detected by a tuned circuit antenna. whose inductive winding is planar. It relates more particularly to improvements to the device for reading or reading / writing such electronic tags in order to supply them regardless of the orientation in the space of the inductive winding of the tuned circuit of the antenna. To this end, the invention provides for creating, by the reading or reading / writing device, a magnetic field rotating in space.
• the electronic tags are produced using microcircuits arranged substantially along a plane in which are wound some turns carrying out the inductive winding of the tuned circuit of the antenna.
• the radiation pattern of such antennas is not omnidirectional because they are not sensitive to the lines of force of a magnetic field which would be coplanar but have a maximum sensitivity to the lines of force which would be orthogonal to the plane of the turns of the winding. .
• these labels have any orientation in space with respect to the magnetic field emitted by the reading or reading / writing device and this is the case. likewise the plane of the turns of the winding so that certain labels may not be coupled or little coupled to the transmitting antenna and this results in an absence of supply or an insufficient supply of the corresponding labels.
• the object of the present invention is therefore to produce a device for emitting an electromagnetic field which makes it possible to supply the electronic tags and therefore to communicate with them whatever the orientation in space of the antenna of the 'label, and therefore the position of the product, relative to the emission device. This object is achieved by creating a magnetic field rotating in space using three orthogonal antennas which are supplied by amplitude and phase controlled currents.
• the invention therefore relates to a device for creating a magnetic field rotating the space with a view to feeding contactless electronic labels, characterized in that it comprises:
• FIG. 1 schematically represents two windings of orthogonal antennas creating orthogonal magnetic fields as well as their vector composition
• FIG. 2 is a diagram showing the vector composition of three orthogonal magnetic fields
• FIG. 3 is a diagram showing the volume described by the vector result of three orthogonal magnetic fields according to the invention.
• FIG. 4 is a block diagram of a device according to one invention for obtaining a magnetic field rotating in space.
• a turn 10 supplied by a current Ix represents an antenna Ax which creates a magnetic field Hx oriented along an axis PX; similarly, a turn 12 supplied by a current ly represents an antenna Ay which creates a magnetic field Hy oriented along an axis PY.
• the magnetic fields Hx and Hy are also orthogonal and located in the plane of Figure 1.
• the vector composition of these two magnetic fields Hx and Hy gives a resulting field Hr (x, y). This vector composition shows that a variation in the amplitude of one of the vectors representing Hx and Hy affects the amplitude and the direction of the resulting field Hr (x, y).
• a third antenna Az (not shown) constituted by a planar winding supplied by a current Iz and arranged in the plane of FIG. 1 will create a magnetic field Hz directed perpendicular to the plane defined by the vectors Hx and Hy. As shown in the vector diagram in Figure 2, the magnetic field vector Hz will be combined with the vector Hr (x, y) to create a resulting magnetic field Hr (x, y, z). If, at the same time as the sinusoidal modulation of pulsation w.
• control of the amplitude and of the phase of the components Hx, Hy and Hz allows the control of the amplitude and of the direction in space of the resulting vector Hr (x, y, z).
• the diagram in FIG. 3 makes it possible to determine the values of the magnetic fields Hx, Hy and Hz as a function of the value of the field Hr (x, y, z) represented by the vector OH of the angle between the vector Hr (x, y) and the vector Hx and the angle ⁇ between the vector Hr (x, y, z) and the vector Hr (x, y).
• Hx
• sin ⁇ .cos ⁇ Hz
• the device for generating a vector H is represented by the functional diagram of FIG. 4 and consists in controlling the amplitude of the currents Ix, ly and Iz at the carrier frequency F Q which supply the antennas Ax, Ay and Az respectively.
• the current Icos ⁇ t of the oscillator is multiplied respectively by cos ⁇ (t) .cos ⁇ (t), in the multiplier circuit 50, by sin ⁇ (t) .cos / 3 (t ) in the multiplier circuit 48, by sin3 (t) in the multiplier circuit 46.
• the sino- (t) and cos ⁇ (t) values are obtained respectively by circuits 30 and 32 from the values of the function (t).
• the values of sin; 8 (t) and cos / 3 (t) are obtained respectively by circuits 24 and 26 from the values of the function ⁇ (t).
• the multiplier circuits 34 and 36 respectively carry out the multiplications sin ⁇ (t) .cos / 3 (t) and cos ⁇ (t) .cos3 (t) whose results are applied to the multiplier circuits 48 and 50 respectively.
• the functions ⁇ (t) and? (t) can be continuous or discrete functions of time.
• the functions of the elements described in connection with Figure 4 are preferably performed by computer means such as a microprocessor. As indicated above, if ⁇ (t) and / 3 (t) are sinusoidal functions of time, the end of the vector OH will describe a sphere.
• point H will describe an ellipsoid of revolution, which makes it possible to favor certain directions of the magnetic field.
• the three elongations can be modified so that the magnetic field vector Hr (x, y, z) has different values according to the directions of space. The modifications of these elongations can be obtained by inserting a circuit for this purpose on the terminal of output of multipliers 46, 48 and 50, which amounts to modifying the value of I.
• the invention has been described with a constant phase looparia, but the invention can be implemented with a phase ⁇ which is variable over time in a continuous or discrete manner. Similarly, the elongations can be variable over time in a continuous or discrete manner and this independently between the antennas.

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• Engineering & Computer Science (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Physics & Mathematics (AREA)
• Computer Networks & Wireless Communication (AREA)
• General Health & Medical Sciences (AREA)
• Electromagnetism (AREA)
• Artificial Intelligence (AREA)
• Computer Vision & Pattern Recognition (AREA)
• General Physics & Mathematics (AREA)
• Theoretical Computer Science (AREA)
• Signal Processing (AREA)
• Variable-Direction Aerials And Aerial Arrays (AREA)

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Applications Claiming Priority (2)

Publications (1)

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ID=9524584

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Cited By (6)

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Citations (4)

• 1998
  • 1998-03-27 FR FR9803832A patent/FR2776864B1/fr not_active Expired - Fee Related
• 1999
  • 1999-03-12 EP EP99907697A patent/EP1066584A1/fr not_active Ceased
  • 1999-03-12 JP JP2000541624A patent/JP2002510096A/ja active Pending
  • 1999-03-12 WO PCT/FR1999/000557 patent/WO1999050780A1/fr not_active Application Discontinuation

Patent Citations (4)

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