JP2009200748A - Coil antenna unit, non-contact type electronic card and portable communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil antenna unit especially suitable for simplifying and ensuring resonance frequency adjustment, a non-contact type electronic card and a portable communication device. <P>SOLUTION: The coil antenna unit includes an LC resonance circuit connected between first and second terminals, and includes an antenna coil and an adjustment inductor serially connected between the first and second terminals, a first adjustment switch connected in parallel to both ends of the adjustment inductor, a reference capacitor connected between the first and second terminals, an adjacent capacitor connected in parallel to the reference capacitor, and a second adjustment switch serially connected to the adjustment capacitor between the first and second terminals. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a coil antenna device, a contactless electronic card, and a portable communication device.

  In recent years, a non-contact type electronic card generally called a non-contact type IC electronic card is used not only in the electronic money field but also in a ticket, etc., and its application is increasingly expanding. For example, mobile communication such as a mobile phone It has begun to be applied to equipment. Such portable communication is performed by an electromagnetic induction method, and its operating frequency is normally 13.56 MHz. Therefore, the resonance frequency (f (Hz) = (1 / 2π) × (1 / √ (LC))) of the antenna device used for the non-contact type electronic card is adjusted to be a value close to the operating frequency. .

  However, due to variations in the electrical characteristics of components such as coils, inductors and capacitors incorporated in non-contact type electronic cards and misalignment of parts for each card, there are some mass-produced non-contact type electronic cards. In some cases, the resonance frequency deviates from the allowable range of the operating frequency, and the resonance frequency needs to be adjusted so that the resonance frequency falls within the allowable range. As an example of the prior art relating to the non-contact type IC electronic card that enables the resonance frequency to be adjusted, there are the following prior art 1 and prior art 2.

  (Prior Art 1): It is described that the resonance frequency is adjusted by the capacitance C by cutting a part of a plurality of adjustment capacitors arranged in the resonance circuit of the non-contact IC electronic card (Patent Document). 1).

  By the way, even if a non-contact type electronic card having the same resonance frequency as the operating frequency is mass-produced under the same specifications, the resonance frequency value also varies from product to product due to variations in the characteristics of the components described above. As a result, the quantity distribution corresponding to the resonance frequency of the intermediate product during the manufacturing process generally exhibits a mountain-shaped distribution line 41 as shown in FIG.

  On the other hand, a user-standard range 43 (left and right range with the center line 42 in the figure), for example, ± 150 KHz for the operating frequency of the communication device indicated by the center line 42 is set as an allowable range (non-defective product). . When a non-contact IC card is manufactured with a design specification in which the maximum value of the distribution line 41 matches the center line 42, as shown in the left and right hem portions 41a and 41b of the distribution line 41. In this case, a non-standard product that protrudes from the range 43 is generated.

  According to the prior art 1, the adjustment of the resonance frequency is limited to one-way adjustment of the resonance frequency only in the increasing direction by reducing the capacitance C, so that the left skirt portion 41a can be adjusted and the standard range 43 can be brought into a non-defective product, but the right skirt portion 41b cannot be adjusted, resulting in a defective product.

  Therefore, as shown in FIG. 4B, the resonance frequency of the design specification is made lower than the operating frequency so that the maximum value of the distribution line 41 is shifted to the left side of the center line 42. There is a case. In this case, the right skirt portion 41b is included in the standard range 43, and the portion 41A that protrudes to the left side of the standard range 43 becomes a non-defective product within the standard range 43 by unidirectional adjustment by reducing the capacitance C. Can be shifted. On the other hand, since the quantity of the object to be adjusted in the protruding portion 41A is remarkably increased, the adjustment and measurement of the object to be adjusted are grouped by a certain adjustment width and repeated, and the production of the IC card is repeated. There is a problem that it is complicated and causes an increase in production time and manufacturing cost.

  (Prior Art 2): A plurality of individual connection pads arranged along the longitudinal direction of a long common connection pad connected to one end of the antenna are respectively connected to a plurality of intermediate terminal portions of the antenna, It is described that the resonant frequency is adjusted by inductance by mounting an IC chip on one individual connection pad and a common connection pad selected from the individual connection pads (Patent Document 2).

In this prior art 2, when large variations in inductance characteristics occur in each lot when IC cards are mass-produced, individual resonance frequencies cannot be predicted, and the IC chip can be connected at any position. There is a possibility that it may not be possible to specify whether or not it should be connected to the pad, or an appropriate resonance frequency adjustment cannot be performed. In addition, in order to know the resonance frequency, it must be measured after mounting the IC chip. If the measurement result is out of the specified range, the adjustment becomes impossible or the chip is remounted. There is a problem.
Japanese Patent Laid-Open No. 2001-10264 Japanese Patent Laid-Open No. 2006-217185

  An object of the present invention is to solve the above-described problems of the prior art, and in particular, to provide a coil antenna device, a non-contact type electronic card, and a portable communication device suitable for simplifying and ensuring the resonance frequency adjustment. To do.

  The coil antenna device of the present invention according to claim 1 is a coil antenna device having an LC resonance circuit connected between first and second terminals, wherein the coil antenna device is connected in series between the first and second terminals. An antenna coil, an adjustment inductor, a first adjustment switch connected in parallel to both ends of the adjustment inductor, a reference capacitor connected between the first and second terminals, and a parallel connection to the reference capacitor An adjustment capacitor is provided, and a second adjustment switch connected in series to the adjustment capacitor between the first and second terminals.

  According to a second aspect of the present invention, in the coil antenna device according to the first aspect, an insulating substrate as a base and first and second terminals provided on a part of the insulating substrate are provided. The antenna coil is disposed along the periphery of the insulating substrate, and the adjustment inductor comprises an inductor pattern layer provided on the insulation substrate, and the first and second adjustment coils are provided. The switch includes a wiring pattern layer provided on the insulating substrate.

  According to a third aspect of the present invention, in the coil antenna device according to the second aspect, the antenna coil includes a coiled pattern layer formed along the periphery of the insulating substrate.

  According to a fourth aspect of the present invention, in the coil antenna device according to any one of the first to third aspects, the first and second adjustment switches are selectively turned off from an on state. The resonant frequency is decreased by increasing the inductance of the inductor, and the resonant frequency is increased by decreasing the capacitance due to the reference capacitor and the adjustment capacitor connected in parallel to each other. It is made possible to do.

  According to a fifth aspect of the present invention, in the coil antenna device according to the fourth aspect, the selective off state of the first and second adjustment switches is the selected first and second adjustment switches. It is obtained by cutting a wiring pattern layer to be formed.

  A contactless electronic card according to a sixth aspect of the present invention is an active element chip connected to the first and second terminals, and a coil antenna device according to any one of the first to fifth aspects. Is stored in a card-shaped container.

  A portable communication device according to a seventh aspect of the present invention is characterized in that the coil antenna device according to any one of the first to fifth aspects is accommodated in a casing for a portable communication device.

  The coil antenna device, non-contact type electronic card, and portable communication device of the present invention can adjust the resonance frequency by both the adjustment inductor and the adjustment capacitor, so that the number of objects to be adjusted for the resonance frequency in mass production is minimized. Therefore, the resonance frequency can be easily and reliably kept within the standard range. And the good product quantity of these products concerning this invention can be improved reliably, The manufacture can be simplified and there can exist an effect that production time and manufacturing cost can be reduced.

  Hereinafter, an embodiment of a coil antenna device of the present invention will be described with reference to FIGS. 1 is a circuit diagram of a coil antenna device according to an embodiment of the present invention, FIG. 2 is a plan view showing a structure in which the circuit shown in FIG. 1 is incorporated in the coil antenna device, and FIG. 3 is a coil according to the embodiment. It is a distribution map for demonstrating adjustment of the resonant frequency of an antenna apparatus.

  First, the circuit configuration of the coil antenna device having the LC resonance circuit in the present embodiment will be described with reference to FIG. 1. The first terminal P1 and the second terminal P2 are, for example, semiconductor ICs mounted on the coil antenna device. It is connected to an active element chip 1 made of LSI or the like.

  An antenna coil L0 and a series of a plurality of adjustment inductors L1 to Lm are connected in series between the first and second terminals P1 and P2. The antenna coil L0 has an inductance of, for example, 1.8 μH, and the adjustment inductors L1 to Lm may be only one (m = 1) as necessary, and the individual adjustment inductors L1 to Lm may be provided. The ratio of inductance to the antenna coil L0 is set to about 1/100, for example. A plurality of first adjustment switches SL1 to SLm are connected in parallel to both ends of each of the adjustment inductors L11 to L1m.

  On the other hand, the resonance circuit capacitor C connected between the first and second terminals P1 and P2 is connected in parallel to the antenna coil L0 and the plurality of adjustment inductors L1 to Lm, and is parallel to each other. A reference capacitor C0 and a plurality of adjustment capacitors C1 to Cn are connected. The reference capacitor C0 is, for example, 60 pF, and the adjustment capacitors C1 to Cn may be only one (n = 1) if necessary, and each of the adjustment capacitors C1 to Cn is connected to the reference capacitor C0. The capacitance ratio is set to about 1/100, for example.

  A plurality of first adjustment switches SC1 to SCn are connected in series to each of the adjustment capacitors C1 to Cn. The first adjustment switches SC1 to SCn are shown as being connected to the upper side of the adjustment capacitors C1 to Cn in the figure, but are connected in series between the first and second terminals P1 and P2. What is necessary is just to connect to the lower side of the capacitors C1 to Cn for adjustment.

  Further, the first and second adjustment switches SL1 to SLm and SC1 to SCn before adjustment of the resonance frequency are in an on state, and the adjustment capacitors C1 to Cn are in an operable state, and the adjustment inductors L1 to Lm are in an operable state. Is inoperable. Therefore, when the inductance is increased in adjusting the resonance frequency, at least one of the first adjustment switches SL1 to SLm is selectively turned off to turn off at least one of the adjustment inductors L1 to Lm. Switch to the ready state (function start). When reducing the capacitance, at least one of the second adjustment switches SC1 to SCn is selectively turned off to switch at least one of the adjustment capacitors C1 to Cn to an inoperable state ( Stop functioning).

  By the way, the resonance frequency (f (Hz) = (1 / 2π) × (1 / √ (LC))) of the coil antenna device is generally used for an operating frequency of a communication device adapted to this device, for example, a portable communication device. Is set to correspond to 13.56 MHz.

  Therefore, in the design specification, when the resonance frequency matches the operating frequency, the capacitance value of the capacitor C for the resonance circuit having a parallel connection configuration of the reference capacitor C0 and the adjustment capacitors C1 to Cn, and the antenna The inductance value of the coil L0 is set in advance so as to have the resonance frequency of 13.56 MHz.

  Even if set in this way, the mass-produced coil antenna device is actually out of the standard as shown in the distribution line 41 shown in FIG. 4A as described in the description of the prior art. Often has a distribution that includes resonant frequencies. In this case, when the first and second adjustment switches are operated, the resonance frequency is decreased by increasing the inductances by the adjusting inductors L1 to Lm or increasing by decreasing the capacitance by the adjusting capacitors C1 to Cn. , And can be adjusted from the left and right sides (sides) of the distribution line.

  Next, an example of the structure of the coil antenna device having the circuit configuration will be described with reference to FIG. Here, the insulating substrate 2 serving as a base for the structure of the coil antenna device is formed in a long rectangular card shape, and on the upper surface thereof, the mounting position of the active element chip 1 (see FIG. 1) is provided. The first and second pads (terminals) P1 and P2 constituting the first and second terminals are arranged at a predetermined interval.

  The antenna coil L0 disposed at the peripheral position of the insulating substrate 2 has a spiral shape along the periphery of the long rectangle on the upper surface of the insulating substrate 2, and one end of the antenna coil L0 serves as the second pad (terminal) P2. The other end is connected to one end on the L1 side of the series of adjusting inductors L1 to Lm.

  The series of adjusting inductors L1 to Lm are thin-film passive elements formed on a part of the upper surface of the insulating substrate 2 by, for example, screen printing of carbon paste, for example, an inductor pattern patterned in a crank meandering manner. Formed by layers. Of course, the adjustment inductor may be a chip inductor.

  The other end of the series of adjusting inductors L1 to Lm on the Lm side is connected to the first pad (terminal) P1 through a first wiring layer 3 formed on the upper surface of the insulating substrate 2. For each of the adjustment inductors L1 to Lm, the first adjustment switches SL1 to SLm connected in parallel to both ends of each inductor are electrically short-circuited at both ends of each adjustment inductor so as to be turned on. The wiring pattern layer is provided on the upper surface of the insulating substrate 2. The wiring pattern layer is a planar pattern having a main trunk portion parallel to the adjustment inductors L1 to Lm and branch portions extending to both ends of each inductor.

  The second wiring layer 4 formed on the upper surface of the insulating substrate 2 has a portion parallel to the first wiring layer 3 at a predetermined interval, and one end thereof is the second pad (terminal). Connected to P2.

  A resonant circuit capacitor C provided between the first wiring layer 3 and the second wiring layer 4 includes a reference capacitor C0 arranged in parallel on the upper surface of the insulating substrate 2 and a plurality of adjustments. The capacitors C1 to Cm are used. These capacitors C0 to Cm are provided, for example, by mounting a thin film capacitor chip on a wiring land portion (not shown) on the insulating substrate 2.

  The reference capacitor C0 is the main part of the capacitor C for the resonance circuit and always functions, and is connected by the third wiring layer 5 between the first wiring layer 3 and the second wiring layer 4. Has been. The adjustment capacitors C1 to Cm are connected between the first wiring layer 3 and the second wiring layer 4 through second adjustment switches SC1 to SCn, respectively. The second adjustment switches SC1 to SCn are each composed of a wiring pattern layer formed on the upper surface of the insulating substrate 2 so as to be connected in series to the adjustment capacitors C1 to Cm.

  The capacitors C0 to Cm are not limited to thin film chips, and all or part of the insulating substrate 2 in the thickness direction is used as a capacitor dielectric, and both capacitor electrodes are arranged in the thickness direction. Thus, it can be configured as a built-in capacitor. In this case, in the capacitors C0 to Cm shown in FIG. 2, one capacitor electrode is disposed on the upper surface side of the insulating substrate 2, and the other capacitor electrode is disposed on the lower surface (back surface) side. Formed by. Therefore, the second wiring layer 4 is formed on the lower surface (back surface) side of the insulating substrate 2 instead of the embodiment shown in FIG. Further, the capacitor may be formed by forming parallel electrode pattern layers corresponding to both electrodes of the capacitor on the surface of the insulating substrate 2.

  Note that, for example, in order to maintain the insulating property at the intersection of the wiring as in the case where the connection portion between the one end of the antenna coil L0 and the second pad P2 intersects with a part of the antenna coil L0. In addition, an interlayer connection technique using through holes and via holes in general jumper wiring or printed wiring may be applied. Moreover, the arrangement pattern of each element such as the adjustment inductors L1 to Lm, the capacitors C0 to Cm, the first and second terminals P1 and P2, is not limited to the form shown in FIG. You can also.

  In order to turn off the first and second adjustment switches SL1 to SLm and SC1 to SCn, the wiring pattern layers constituting the switches SL1 to SLm and SC1 to SCn are mechanically scratched or What is necessary is just to cut | disconnect by simple means, such as a laser cut. Referring to FIG. 2, an example of a cutting point for turning off the first adjustment switch SL1 and the second adjustment switch SCn selected for adjusting the resonance frequency is indicated by a cross.

  Of course, other means such as dividing a part of each wiring pattern layer in advance, providing a fuse layer corresponding to each switch in that part, and cutting by energization fusing may be used. However, the mechanical scribing or laser cutting is preferable because pattern formation and cutting work are simple.

  Here, a description will be given of the constituent materials of the coil antenna device. As the insulating substrate 2, for example, polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) is used, and the wiring pattern layers for each switch, the circuit wiring layers 3 to 5 and the antenna coil L0 are formed on the surface of the substrate, for example. A conductive paste such as silver paste can be formed into a thin layer by screen printing with a desired pattern.

  Further, a copper clad laminated substrate (CCL) is used as a base material, and an insulating film of this CCL is applied as the insulating substrate 2, and the copper foil layer is subjected to desired patterning to form a wiring pattern layer for each switch. The circuit wiring layers 3 to 5 and the antenna coil L0 may be formed. For the CCL, an FPC / RPC type may be appropriately selected and employed according to the application field of the coil antenna device.

  Next, adjustment of the resonance frequency of the coil antenna device according to the embodiment of the present invention will be described with reference to FIG. The horizontal axis in FIG. 3 represents the resonance frequency value, and the vertical axis represents the quantity distribution corresponding to the resonance frequency value of the mass produced coil antenna device.

  Also in the coil antenna device according to the present embodiment, the product quantity distribution corresponding to the resonance frequencies of a large number of intermediate products in the manufacturing process exhibits a mountain shape as indicated by the distribution line 10 as in the case of the prior art 1, and mobile communication. A user standard range 12 straddling the left and right of the center line 11 corresponding to the operating frequency of the device is shown as a range of ± 150 KHz, for example.

  The mass-produced coil antenna device is manufactured as a design specification so that the resonance frequency thereof matches the operating frequency (the maximum value of the distribution line 10 and the center line 11 overlap). However, in the left and right skirt portions 10 a and 10 b of the distribution line 10, there may be a case where a non-standard part protruding from the standard range 12 occurs as in the case of the description of the prior art 1.

  Therefore, for the coil antenna device distributed in the left skirt portion 10a, the capacitance of the capacitor C is reduced by selectively turning off the second adjustment switches SC1 to SCn, so that the resonance frequency is within the standard range 12. Shift in the increasing direction.

  For the coil antenna device distributed in the right skirt portion 10b, the inductance due to the antenna coil L0 and some of the adjustment inductors is increased by selectively turning off the first adjustment switches SL1 to SLm. The resonance frequency is shifted within the standard range 12 in a decreasing direction.

  In this way, all of the coil antenna devices distributed in the left and right hem portions 10a and 41b, which are defective products out of the standard range in the initial state, are adjusted as adjustment targets and within the standard range 12 (non-defective product). Can be brought in. As a result, the number of coil antenna devices corresponding to the standard range 12 increases, and the increase is expressed by the distribution line 13 (broken line). In this expression, the distribution line 13 regards the presence of an increase corresponding to the skirt portions 10a and 41b as an area of the increase, and does not stick to the curved shape.

  By the way, when the resonance frequency standard range 12 is a relatively wide range of ± 150 KHz, the shift amount by one adjustment can be a large shift amount, for example, about 100 KHz. One capacitor can be provided each having an inductance and a capacitance corresponding to a shift amount of 100 KHz. In this way, when the shift amount of one time is within the standard range 12 and as large as possible, the number of adjustments and the number of parts of the adjustment inductor and capacitor can be minimized.

Further, as the standard range 12 becomes a narrow range of ± 150 KHz or less, it is necessary to set the shift amount in one adjustment to be small, in order to meet the diversification of the setting range of the standard range 12 on the user side. the adjustment inductor L1~Lm and adjustment capacitor C0～C m, corresponding to different shift amount, may magnitude relation of the inductance and capacitance should incorporate different stepwise.

  Further, if a combination of an adjusting inductor and a capacitor so that the shift amount is a small amount of, for example, 50 KHz or less, the coil antenna device that is already a good product distributed near the outermost contour in the standard range 12 is provided. Further, by adjusting the maximum width of the distribution line 10, the maximum width of the distribution line 10 can be made smaller than the standard range 12 width. That is, it is possible to provide a coil antenna device with high quality having a resonance frequency closer to the operating frequency by increasing the sharpness of the distribution line 10. When the adjustment from both sides (both sides) of the standard range 12 is performed in a narrow distribution range in which the number of adjustments is not a burden in consideration of the shift amount as described above, a product having a quality close to the operating frequency can be easily obtained. There is an advantage that it can be obtained reliably.

  As described above, in the coil antenna device according to the present embodiment, since the frequency shift can be adjusted from both sides (both sides) of the distribution line 10, the number of resonance frequency adjustment target items in mass production is minimized. The resonance frequency can be easily and reliably kept within the standard range. In addition, the quantity of non-defective products can be reliably improved, and the production can be simplified to reduce the production time and production cost. In addition, the resonance frequency can be easily adjusted from both sides of the operating frequency standard range by simply cutting the wiring pattern layer of the adjustment switch without problems such as the inability to adjust after mounting the IC chip as in the prior art 2. .

  The second adjustment switches SC1 to SCn are for selectively turning off the adjustment capacitors C0 to Cn to stop their functions. Therefore, in order to obtain the off state, the wiring pattern layer as described above is used. Instead of the cutting method (first method), a method (second method) for selectively removing the adjustment capacitors C0 to Cn themselves may be employed. Therefore, in the present invention, the second adjustment switches SC1 to SCn are defined as including the first and second methods.

  The present invention further provides a contactless electronic card incorporating the coil antenna device according to the above-described embodiment. In this case, the insulating substrate 2 in the coil antenna device is formed in a card shape or a tag shape, and the entire front and back surfaces thereof are flattened so that electronic components such as IC chips to be mounted do not protrude excessively. Is done.

  A surface film (not shown) on which the card type and the like are printed and a back film (not shown) on which handling instructions are printed are attached to both surfaces of the insulating substrate 2. In this manner, the insulating substrate 2 and the front and back films constitute a card-like container (not shown), and the coil antenna device is housed or built in the card-like container.

  The term “card” of the non-contact type electronic card of the present invention is defined to include various shapes such as a card shape, a tag shape, or a ribbon shape according to a user request.

  Furthermore, the present invention provides a portable communication device incorporating the coil antenna device according to the above-described embodiment. In this case, the coil antenna device is housed in a housing constituting a main body of a mobile communication device such as a mobile phone. By the way, although the antenna coil L0 of the coil antenna device in the one embodiment is formed in a thin layer by printing or the like, it is configured by using an antenna wire wound in a coil shape and accommodated in the space of the housing. May be.

  Such a non-contact type electronic card and portable communication device of the present invention have the same effects as those of the coil antenna device according to the embodiment.

It is a circuit diagram which shows the circuit structure of the coil antenna apparatus of one Embodiment of this invention. It is a top view which shows the structure of the coil antenna apparatus of one Embodiment of this invention. The distribution map for demonstrating adjustment of the resonant frequency in the coil antenna apparatus of one Embodiment of this invention. It is a distribution map for demonstrating adjustment of the resonant frequency in the conventional coil antenna apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Active element chip 2 Insulating substrate 3 1st wiring layer 4 2nd wiring layer 5 3rd wiring layer C Capacitor C0 for resonance circuits Reference capacitor C1-Cn Adjustment capacitor L0 Antenna coil L1-Lm Adjustment inductor SL1-SLm 1st 1 adjustment switch SC1 to SCn second adjustment switch P1 first terminal (pad)
P2 Second terminal (pad)

Claims (7)

  A coil antenna device having an LC resonance circuit connected between a first terminal and a second terminal, wherein the antenna coil and the adjustment inductor connected in series between the first and second terminals, and both ends of the adjustment inductor Between the first and second terminals, a first adjustment switch connected in parallel to the reference capacitor, a reference capacitor connected between the first and second terminals, an adjustment capacitor connected in parallel to the reference capacitor, and A coil antenna device comprising: a second adjustment switch connected in series to the adjustment capacitor.   An insulating substrate as a base; and first and second pads constituting the first and second terminals provided on a part of the insulating substrate, wherein the antenna coil is disposed along the periphery of the insulating substrate. The adjusting inductor includes an inductor pattern layer provided on the insulating substrate, and the first and second adjusting switches include a wiring pattern layer provided on the insulating substrate. Item 2. The coil antenna device according to Item 1.   The coil antenna device according to claim 2, wherein the antenna coil includes a coiled pattern layer formed along a periphery of the insulating substrate.   The first and second adjustment switches are selectively turned off from the on state, the inductance of the inductor is increased to reduce the resonance frequency, and the capacitance due to the reference capacitor and the adjustment capacitor connected in parallel to each other is increased. The coil antenna device according to any one of claims 1 to 3, wherein an adjusted resonance frequency can be obtained by reducing and increasing the resonance frequency.   5. The selective OFF state of the first and second adjustment switches is obtained by cutting a wiring pattern layer that constitutes the selected first and second adjustment switches. The coil antenna apparatus as described.   An active element chip connected to the first and second terminals and the coil antenna device according to any one of claims 1 to 5 are housed in a card-shaped housing. Expression electronic card.   A portable communication device comprising the coil antenna device according to any one of claims 1 to 5 housed in a casing for a portable communication device.

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