JP3591185B2 - Wireless module and information processing apparatus provided with wireless module - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a terminal that uses a millimeter wave or a microwave as a wireless carrier, and more particularly to a wireless terminal that needs to control the directivity of an antenna.
[0002]
[Prior art]
17A and 17B show a conventional example of a wireless terminal. FIG. 17A is an external view and FIG. 17B is an internal configuration diagram. A baseband circuit 177 that performs signal modulation / demodulation and logical processing is mounted on a mounting board 178. The baseband circuit 177 is connected to the IF circuit 175 by a transmission line on the mounting board 178 and a connector 176. The IF circuit 175 and the RF circuit 173 are mounted on the front and back with the substrate 174 interposed therebetween, and are electrically connected. The RF circuit 173 is connected to the antenna 171 via the cable 172. As described above, in the conventional wireless terminal, the antenna 171 and the mounting board 178 are firmly fixed to the case 179 of the wireless terminal, and no movable part is provided.
[0003]
For this reason, the directivity of the antenna is generally omnidirectional, and when a directional antenna is used, the wireless terminal itself must be tilted in a certain direction according to the directivity. Was.
[0004]
[Problems to be solved by the invention]
If millimeter waves and microwaves are used as wireless carriers, more information can be propagated. However, when a high-frequency signal is used as a carrier, the straightness of the electromagnetic wave increases, so that it is necessary to more accurately match opposing antenna surfaces. Therefore, the use of an omnidirectional antenna as in the related art can be said to be one solution, but the loss is large. In order to increase the gain, the directivity of the antenna should be increased, and the antenna surface should be movable so that the antennas can be surely matched.
[0005]
On the other hand, when a radio circuit is mounted, transmission lines such as coaxial cables and microstrip lines for transmitting high-frequency signals of millimeter waves and microwaves suddenly increase in transmission signal attenuation above a specific frequency (cutoff frequency). Therefore, it becomes impossible to transmit a signal in a frequency band higher than that. The cutoff frequency is determined by the diameter of the coaxial cable and by the thickness of the substrate of the microstrip line. Therefore, in order to transmit a high-frequency signal, it is necessary to form a transmission path having a small diameter and a small thickness.
[0006]
Particularly, in a matching circuit, an RF circuit and an IF circuit in which active devices are connected in a complicated manner, when the characteristic impedance of the transmission line is discontinuous at the connection point, the input / output reflection of the signal at the discontinuity point. Since the signal is generated and attenuated, high precision of fine processing is required.
[0007]
Therefore, when transmitting a high-frequency signal whose processing accuracy is not negligible compared to the wavelength of the frequency to be used, transmission is performed using a laser or exposure device with high processing accuracy so that the processing variation of the pattern does not affect the characteristic impedance of the transmission line. Create a road pattern. Therefore, a microstrip substrate is manufactured using a quartz or alumina substrate having a uniform substrate thickness, a small signal loss, and capable of processing a fine transmission line pattern.
[0008]
However, in a transmission line using a rigid substrate, a movable portion cannot be provided in the middle, and there is no other way than to adjust the antenna surface by moving the entire wireless terminal.
[0009]
The present invention has been made in view of the above problems, and has as its object to provide a wireless module in which a directional antenna is movable.
[0010]
[Means for Solving the Problems]
In a wireless terminal having an IF circuit for converting a baseband signal to an IF signal of an intermediate frequency, an RF circuit for converting the IF signal to an RF signal of a carrier frequency, and an antenna for radiating the RF signal with a predetermined directivity, Each of the RF circuit and the antenna is formed on a hard substrate, and at least the IF circuit and the RF circuit are connected by a balanced strip transmission line provided on a dielectric substrate having a thinned dielectric layer.
[0011]
Further, a movable connector is provided in the middle of the transmission path of the IF circuit and the RF circuit.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a diagram showing a configuration of a wireless terminal according to the present invention. Reference numeral 1 denotes a wireless module for transmitting and receiving electromagnetic waves, and reference numeral 2 denotes a functional block for executing functional processing on signals transmitted and received by the wireless module. The wireless module 1 connects an antenna 3 that emits electromagnetic waves, an RF circuit 4 that handles millimeter-wave signals, an IF circuit 5 that uses signals below microwaves, and a baseband circuit 6 that modulates and demodulates signals. And a movable connector 8.
[0013]
The antenna 3 is a planar antenna in which conductor patterns are weighted so as to have directivity of several degrees to several tens degrees on the upper surface. When transmitting from a wireless terminal, the signal from the functional block 2 is subjected to various processes required for transmission in the baseband circuit 6 and transmitted to the IF circuit 5. The IF circuit 5 converts the baseband signal into an IF signal. The signal raised to the intermediate frequency is transmitted to the RF circuit 4 through the movable connector 8, and is converted into an RF signal by the RF circuit 4. The signal raised to the carrier frequency is transmitted to the antenna 3 and radiated. The movable connector 8, the RF circuit 4, and the antenna 3 are mutually connected by a microstrip line provided on the mounting substrate 7.
[0014]
The signal received by the wireless terminal is transmitted to the functional block 2 through the reverse path from the antenna 3.
[0015]
The first embodiment of the wireless terminal according to the present invention will be described in detail with reference to FIGS. FIG. 2 shows a cross-sectional view of the wireless terminal of FIG. In FIG. 2, components denoted by the same reference numerals as those in FIG. 1 indicate the same components.
[0016]
The mounting board 7 is provided with a microstrip line for transmitting a high-frequency signal. The mounting substrate 7 covers the upper and lower surfaces of the dielectric layer 21 (indicated by two thick lines) with conductive layers 22a and 22b serving as GND surfaces, and a conductive layer serving as a signal line is provided in the center of the dielectric layer 21. It has a structure through which the body layer 23 passes.
[0017]
In a microstrip line, a dielectric layer between conductors is thinned to obtain a required cutoff frequency. When an organic material having a relative dielectric constant of less than 10 is used for the dielectric of the substrate, the thickness of the substrate is about 1 mm or less in order to transmit a high-frequency signal on the order of GHz. Therefore, the mounting board 7 can maintain sufficient flexibility in the vertical direction.
[0018]
In addition, since the microstrip line is formed as a balanced strip transmission line in which both the upper and lower surfaces of the mounting substrate 7 are covered with the GND surface, the mounting substrate 7 may be bent and come close to other metal conductors. , The characteristic impedance value of the transmission line does not greatly fluctuate. In the transmission path where the RF circuit 4 is mounted, the balanced strip transmission path can be maintained by the GND surface 22a on the upper surface of the mounting substrate 7 and the GND surface of the substrate of the RF circuit 4.
[0019]
Further, a millimeter wave signal is transmitted on a transmission path between the antenna 3 and the RF circuit 4. Therefore, the antenna 3 and the RF circuit 4 are arranged adjacent to each other and flip-chip connected by bumps (solder, Au, etc.) 24 in order to minimize the transmission path length and suppress the passage loss.
[0020]
In order to form a microstrip line by processing a dielectric substrate, a chemical etching method is used. In the chemical etching method, it is not possible to accurately process a plurality of lines having different line widths or a line having many bends. However, the accuracy required for processing a signal transmission line between circuits that can be constituted by a line having a simple shape. Can be secured. Therefore, in the present invention, flexibility is realized by using a dielectric (flexible) substrate for signal transmission between circuits.
[0021]
The RF circuit 4 will be described in detail with reference to FIG. (A) is a front view of the RF circuit 4, and (b) is a side view. The RF circuit substrate 31 is made of a quartz, alumina, silicon substrate or the like. On the substrate 31, three layers of a GND layer 32, an insulator layer 33, and a metal layer 34 serving as a transmission path are formed. The insulating layer 33 and the transmission path 34 are processed by generating a transmission path pattern using a laser or an exposure device.
[0022]
On the RF circuit board, a matching circuit such as a capacitor and active devices 35a to 35e are connected by using bumps 36 on the order of several tens of microns to form the RF circuit 4. Via holes 37a-37f are used for grounding active devices. The RF circuit may be formed on-chip as an MMIC (Micro-wave Monolithic IC). Note that the circuit shown in FIG. 3 is merely a schematic diagram for explaining a mounting state of a circuit element. The RF circuit 4 is flip-chip connected to the mounting substrate 7 at, for example, the A section and the B section on the transmission line 34.
[0023]
As described above, by forming the RF circuit on a hard substrate such as quartz, a fine transmission line pattern can be accurately processed by a laser or an exposure apparatus, and the occurrence of a discontinuity in the characteristic impedance can be prevented.
[0024]
The movable connector 8 and the connection between the movable connector 8 and the mounting board 7 will be described in detail with reference to FIG. (A) is a perspective view schematically showing the movable connector 8, and (b) is an equivalent circuit diagram of the movable connector 8. FIG. 4 shows an example in which two microstrip lines 23a and 23b are present. Further, in order to completely prevent the noise from being mixed into the microstrip line, GND surfaces 22c and 22d are provided on the sides of the line.
[0025]
The movable connector 8 includes wiring connecting portions 41a and 41b that connect the metal conductor portion 42 to the metal conductor portion 42 by rearranging the signal lines arranged in the horizontal direction in the vertical direction.
[0026]
The principle of the movable connector will be described in comparison with an equivalent circuit. The microstrip line 23a or 23b of the mounting substrate 7 corresponds to the LC element 43a (43b). The wiring connection part 41a (41b) is a group of conductors connecting the strip transmission line 23a (23b) and the metal conductor part 42 by a line (inductor) having a predetermined inductance component, and is represented by 44a (44b) in an equivalent circuit. Is done. The metal conductor portion 42 is formed by stacking metal conductors which are capacitively coupled to adjacent metal conductors to form a capacitance, and are represented by 45 in an equivalent circuit.
[0027]
Thus, the movable connector 8 realizes conductivity by forming a pass filter in the microwave band. The movable connector 8 is a resonance type band-pass filter, and a frequency (bandpass frequency) f to be passed is represented by a function of an inductance component 44 and a capacitance component 45. If the frequency f is about 300 MHz to 10 GHz, the inductance component 44 becomes about several nano-H, and the capacitance component 45 becomes about several tens pico F. In this case, the diameter of a metal conductor described later is several mm, and the thickness of the insulator is 0.1 mm. This is on the order of several mm, which is optimal from the viewpoint of mechanical processing accuracy and miniaturization of the connector. The inductance component used for resonance is the inductor of the wiring connection part 41, and the capacitance component is formed by adjusting the diameter of the metal conductor 17 and the thickness of the insulator.
[0028]
FIG. 5 shows a cross-sectional view of the metal conductor portion 42. The metal conductors 51, 53 and 55 form GND, and the metal conductors 52 and 54 are connected to the signal lines 23a and 23b, respectively. The metal conductors 51 to 55 are formed in a circular shape so that the capacitance component 45 does not fluctuate due to the rotation. For the insulators 56a to 56f between the metal conductors, an organic material having a small friction coefficient (for example, a Teflon-based organic material) is used so as to rotate smoothly. By using such an organic material, the wear of the surfaces of the metal conductors 51 to 55 can be reduced, so that the durability can be improved.
[0029]
Further, since the movable connector 8 serves as a fulcrum for the rotation of the antenna, the weight of the antenna and the RF circuit is applied to the movable connector 8. At least one or more guides 57, 58 are provided at one or all of the uppermost, lowermost, and middle portions of the metal conductor so that the stress does not cause distortion of the metal conductor due to such a load. The guides 57 and 58 are connected to a support substrate (a case of a wireless module) and maintain necessary strength.
[0030]
The configuration of the wiring connection unit 41 is connected using FIG. (A) is an external view of the wiring connection part 41, (b) is a figure which shows the internal structure of the wiring connection part 41. FIG. The connection port A (transmission line side) 61 is electrically connected to the mounting substrate 7, and the terminals 65 a to 65 e of the connection port B (metal conductor portion side) 62 are electrically connected to the metal conductors 51 to 55, respectively. The connection ports are connected by wires 63 arranged in a wired logic manner in the vertical and horizontal directions. The terminals 65a, c, and e of the connection port B are connected to the GND plane, and the terminals 65b and 65d of the connection port B are connected to the microstrip lines 23a and 23b via inductors 64a and 64b of a predetermined value arranged near the terminals, respectively. I do.
[0031]
As described above, the wireless module 1 according to the present invention is configured such that the antenna 3 having directivity and the RF circuit 4 are mounted on the mounting substrate 7 which is a thin flexible substrate, and the transmission path on the mounting substrate is Are all configured as balanced strip transmission lines, the antenna surface is movable up and down, and the characteristic impedance does not change due to this bending. In addition, the antenna surface becomes movable in the horizontal direction by the movable connector 8 operating as a pass filter in the microwave band.
[0032]
Therefore, since the functional block 2 on which the wireless module 1 is mounted can be arranged or installed at any position regardless of the direction of the facing antenna, the wireless terminal can be arranged without limiting the installation place, and the antenna with high directivity can be arranged. , The gain of the antenna can be increased, so that it is possible to provide a wireless terminal having a wide signal dynamic range.
[0033]
Second Embodiment A wireless terminal according to a second embodiment of the present invention will be described with reference to FIG. FIG. 7 is a sectional view of a wireless terminal according to the second embodiment. In FIG. 7, components denoted by the same reference numerals as those in FIGS. 1 and 2 indicate the same components.
[0034]
The antenna substrate is made of a quartz, alumina, silicon substrate, or the like, and the RF circuit 4 can be realized by replacing the RF circuit substrate 31 shown in FIG. 3 with an antenna substrate. That is, three layers of a GND layer, an insulator layer, and a metal layer of a transmission line are formed on the back surface of the antenna substrate, and the insulator layer and the metal layer are processed by generating a pattern of the transmission line using a laser or an exposure apparatus. A matching circuit such as a capacitor on the RF circuit board and an active device are connected by bumps on the order of several tens of microns to form the RF circuit 4. For the connection between the circuits, a transmission path on the mounting board 7 connected by the bumps 24 can be used.
[0035]
The connection between the antenna surface mounted on the front surface of the antenna substrate and the RF circuit 4 mounted on the back surface can be made only by the conductor patterns on both surfaces of the antenna by using a balun. Via hole connection may be used instead of balun connection.
[0036]
In the second embodiment, when the antenna itself is large or when a plurality of antennas are mounted, the distance between the antenna and the RF circuit, which occurs in the first embodiment, becomes longer, and transmission for supplying power to the antenna is performed. There is an advantage that the problem of an increase in road loss can be avoided.
[0037]
An embodiment for reducing the influence of external noise of the wireless module of the present invention will be described with reference to FIGS. FIG. 8 is an equivalent circuit diagram of another embodiment of the movable connector 8. The movable connector 8 shown in FIG. 8 performs differential input / output. The LC element 83 (84) is an equivalent circuit of a balanced strip transmission line on a mounting board, and the LC element 85 is an equivalent circuit of a movable connector. The signal transmitted through the transmission path is transmitted to both the circuit 81 and the circuit 82. At this time, an inverted signal is input to the circuit 82.
[0038]
Generally, a certain amount of error is allowed in the movable part so that the movable part can operate even if the processing accuracy is low. External noise may enter the gap of the movable portion of the movable connector 8 caused by an error in processing accuracy, propagate to the RF circuit or the IF circuit, and cause a malfunction of the circuit. For this reason, a configuration is adopted in which the transmission path in the movable connector 8 is balanced and the differential input / output is performed.
[0039]
Specifically, in the configuration of the movable connector 8 shown in FIG. 5, a signal transmitted from a transmission line (assumed as a single transmission line) is obtained by inverting a signal transmitted from the transmission line to a metal conductor 52a. To the metal conductor 54a. Then, by taking the difference between the signals output from the metal conductors 52b and 54b, it is possible to cut noise mixing on the transmission line of the movable connector 8 at the circuit input stage, and to secure a wide signal dynamic range. Can be.
[0040]
The electromagnetic shield of the wireless module according to the present invention will be described with reference to FIG. 9 that are the same as those in FIGS. 1, 2, and 7 indicate the same components. Reference numerals 91 and 92 denote support substrates that support each circuit.
[0041]
Since the mounting substrate 7 on which the RF circuit 4 is mounted is a balanced strip transmission line, it basically does not radiate electromagnetic waves to the outside. However, a gap always occurs at the connection point of the antenna 3 and the RF circuit 4. Electromagnetic waves from the outside easily penetrate into Therefore, when the support substrate 91 is formed of a metal conductor or the support substrate 91 is formed of an insulator such as a resin, a metal film is provided on the surface of the support substrate by a thin film, plating, or a bonding technique.
[0042]
Thus, the support substrate 91 has an electromagnetic shielding effect and can be provided to the back surface of the antenna surface to block external noise. Similarly, the supporting substrate 92 of the IF circuit 5 and the movable connector 8 also functions as an electromagnetic shield by forming the supporting substrate with a metal conductor, or by providing a metal film on the surface of the insulating supporting substrate with a thin film, plating, or a bonding technique. And a wide dynamic range of the signal can be secured.
[0043]
A method of using the wireless module of the present invention will be described with reference to FIGS. FIG. 10 is a block diagram showing a configuration when the wireless module 1 of the present invention is connected to an information processing apparatus. Reference numeral 101 denotes a signal processing unit capable of processing the control and software functions of the wireless module 1; 102, an operation unit capable of inputting and outputting commands, programs, and data to and from the signal processing unit; 103, information input by the operation unit 102; And a display unit for displaying a result processed by the signal processing unit 101.
[0044]
11 and 12 show an example in which the configuration of FIG. 10 is embodied. The wireless module unit 1, the signal processing unit 101, the operation unit 102, and the display unit 103 are integrated, and in the configuration of FIG. 11, the display unit 103 can be tilted with other parts. In both cases, the size of the wireless terminal is reduced and portability is achieved by integrating the respective parts.
[0045]
FIG. 13 shows an embodiment in the case where the housing of the information processing apparatus is fixed and used. Those having the same reference numerals as in FIG. 10 perform the same function. 1 is a wireless module unit for exchanging information with the outside, 101 is a signal processing unit, 102 is an operation unit such as buttons, dials, and slides, and 103 is a display unit for displaying information. The housing of the information processing device is fixed, and the orientation of the housing main body is subject to restrictions on arrangement. However, since the antenna surface of the wireless module portion is movable, a favorable wireless communication state can be maintained by adjusting the antenna surface even if the direction of the housing is restricted.
[0046]
FIG. 14 shows a usage mode in which the radio module is covered with the case 141 to protect the radio module antenna surface from an object that physically interferes with the surface and improve the durability of the millimeter wave transmitting / receiving module. The case 141 transmits the electromagnetic wave in the millimeter wave band and protects the wireless module 1 from wind, rain, falling objects, and the like.
[0047]
FIG. 15 shows a mode in which the wireless module unit 1, the signal processing unit 101, the operation unit 102, and the display unit 103 are stored in separate housings, and the housings are connected by cables. Since each part is separated, parts of various specifications including the millimeter wave transmitting / receiving module can be used, so that the configuration of the wireless terminal can be changed according to various uses.
[0048]
FIG. 16 shows an embodiment in which the wireless module and the information processing apparatus are connected by (a) by a cable and (b) by a connector. The wireless module can be exchanged by connecting the millimeter-wave transmitting / receiving module 1 and the functional blocks of the signal processing unit 101, the operation unit 102, and the display unit 103 with a cable or a connector.
[0049]
When the information processing device and the wireless module 1 are connected by a cable, the information processing device and the wireless module 1 can be separated from each other. If the wireless module is placed in a stable position and the antenna surface is fixed, the user can place the information processing device on a desk or a knee. The wireless module can communicate stably even if the information processing device is moved during the work.
[0050]
【The invention's effect】
As described above, according to the present invention, in the wireless module, the mounting substrate is formed of a thin-film circuit substrate using a low dielectric constant organic material, and further includes a balanced strip transmission line having a substrate surface on a GND surface. By doing so, it is possible to realize a circuit board that is flexible in bending in the vertical direction and that does not greatly change the characteristic impedance of the board.
[0051]
In addition, the circuit and the antenna surface are connected by a movable connector section composed of a line having a predetermined inductance component and an LC resonance filter made of a circular metal conductor having a predetermined capacitance component.
[0052]
As described above, by using a flexible circuit board and a rotatable connector in a vertical direction, a millimeter wave transmitting / receiving module in which the antenna surface can freely move up and down and rotate horizontally can be manufactured.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a wireless terminal of the present invention.
FIG. 2 is a diagram illustrating a configuration of a wireless terminal according to the first embodiment of the present invention.
FIG. 3 is a diagram illustrating a configuration of an RF circuit used in the millimeter wave transmitting / receiving module.
FIG. 4 is a diagram showing a connection between a movable connector and a mounting board.
FIG. 5 is a diagram showing a configuration of a movable connector.
FIG. 6 is a diagram showing a configuration of a wiring connection portion of the movable connector.
FIG. 7 is a diagram illustrating a configuration of a wireless terminal according to a second embodiment of the present invention.
FIG. 8 is a diagram showing an equivalent circuit of a balanced input of a movable connector.
FIG. 9 is a diagram showing a configuration of a support substrate in the wireless terminal of the present invention.
FIG. 10 is a block diagram when the wireless module of the present invention is connected to an information processing device.
FIG. 11 is an information processing apparatus in which a wireless module of the present invention is integrally configured.
FIG. 12 shows an information processing apparatus in which a wireless module according to the present invention is integrated.
FIG. 13 is a diagram showing a state in which the wireless module of the present invention is connected to a fixed housing type information processing apparatus.
FIG. 14 is a diagram illustrating a state in which the wireless module of the present invention is connected to a fixed housing type information processing apparatus.
FIG. 15 is a diagram illustrating a state where each element of the information processing apparatus is connected by a cable.
FIG. 16 is a diagram illustrating a state in which the wireless module of the present invention is externally connected to an information processing apparatus.
FIG. 17 is a configuration diagram of a conventional wireless terminal.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Wireless module, 2 ... Functional block, 3 ... Antenna, 4 ... RF circuit, 5 ... IF circuit, 6 ... Baseband circuit, 7 ... Mounting board, 8 ... Movable connector, 21 ... Dielectric layer, 22, 23 ... Conductor layer, 24 bump, 31 RF circuit board, 32 GND layer, 33 insulator layer, 34 metal layer, 35 matching circuit, active device, 36 bump, 37 via hole, 41 wiring connection , 42 ... metal conductor part, 51, 52, 53, 54, 55 ... metal conductor, 56 ... insulator, 57, 58 ... guide, 61 ... connection port A, 62 ... connection port B, 63 ... wiring, 64 ... Inductor, 65 terminal, 91, 92 support substrate, 101 signal processing unit, 102 operation unit, 103 display unit, 141 case.

Claims (1)

A wireless module having an IF circuit for converting a baseband signal to an IF signal of an intermediate frequency, an RF circuit for converting the IF signal to an RF signal of a carrier frequency, and an antenna for radiating the RF signal with a predetermined directivity. ,
Each of the IF circuit, the RF circuit, and the antenna is formed on a hard substrate, and at least the IF circuit and the RF circuit are each a balanced type provided on a dielectric substrate having a thinned dielectric layer. Connected by a strip transmission line ,
The balanced strip transmission line includes a dielectric layer made of an organic material having a low dielectric constant, a conductor layer formed to cover upper and lower surfaces of the dielectric layer, and a central portion of the dielectric layer for transmitting a signal. And a conductor layer to be provided,
In a transmission line connecting the IF circuit and the RF circuit, a first metal conductor connected to the IF circuit is overlapped with the first metal conductor via an insulator, and is connected to the RF circuit. A movable connector having a second metal conductor,
The movable connector is configured such that the intermediate frequency band is a bandpass frequency band due to a capacitance component in which the first metal conductor and the second metal conductor are capacitively coupled and an inductance component in a transmission line;
A directional antenna having a millimeter wave or microwave band as a carrier frequency, an operation unit for inputting an instruction from a user, and a signal obtained from the wireless module or a signal input from the operation unit are stored in advance. Used in an information processing apparatus having a signal processing unit that processes information according to a program and a display unit that outputs a part or all of the information processing result by the signal processing unit,
Without changing the position of the information processing device, configured to be able to adjust the direction of the directional antenna with respect to the antenna that transmits a signal to the information processing device,
A movable antenna unit having an RF circuit for converting the directional antenna and an intermediate frequency band signal to the carrier frequency band signal, and a fixed unit unit for converting at least a baseband signal to the intermediate frequency band signal; ,
A wireless module, wherein the fixed unit and the antenna are connected by a transmission line provided on a flexible dielectric substrate .

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