JP2001135971A - Shielding structure of radio - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio shielding structure which is inexpensive, simple in structure, reduced in weight, and capable of surely shielding the necessary parts of a radio. SOLUTION: A metal shield plate 200 is fixed to a board 100 mounted with a high-frequency circuit, the shield plate 200 is partially cut off, cut parts 201, 202, and 203 are bent toward the board 100, and the tips 201a, 202a, and 203a of the bent parts are connected to the grounding points of the board 100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield structure of a wireless device such as a portable telephone, and more particularly, to a wireless device capable of reducing the size and weight with a small number of parts by forming the shield structure using an integral sheet metal. The shield structure of the machine.

[0002]

2. Description of the Related Art In general, a radio device such as a portable telephone uses a substrate on which a high-frequency circuit such as a reference oscillator, a voltage-controlled oscillator, and a PLL circuit is mounted. A shield structure is required to separate the high frequency from the circuit.

FIG. 10 is a schematic block diagram showing a main part of a radio circuit of a portable telephone.

In FIG. 10, this radio circuit includes an antenna 1, a transmission / reception switch 2, a reception unit 3, a transmission unit 4, and a local signal generation unit 5.

[0005] Here, the local signal generator 5 is provided with two synthesizers, that is, a first synthesizer 51 and a second synthesizer 52.
A synthesizer switching circuit 5 that switches the outputs of the first synthesizer 51 and the second synthesizer 52 and supplies the local signal LO to the transmitter 3 and the receiver 4
3. A power supply 54 for supplying power to each unit of the local signal generator 5 is provided.

A first synthesizer 51 and a second synthesizer 51
, The data D, the clock CK, the data setting signal LE, the data setting signal LE, and the first synthesizer 51 and the second synthesizer, which are control signals common to the first synthesizer 51 and the second synthesizer 52. 52 is a separate battery saving signal BS.
1, a control signal C including a BS2, lock detection signals LD1, LD2, and a reference clock SYSCK including a reference frequency.

A power supply control signal P for controlling the power supply of each section of the first synthesizer 51 and the second synthesizer 52 is applied to the power supply 54, and the first synthesizer 51 and the second synthesizer 52 are applied to the synthesizer switching circuit 53. A synthesizer selection signal S for selecting one of the two synthesizers 52 is added.

FIG. 11 shows details of the local signal generator 5 of the radio circuit.

In the local signal generator 5 shown in FIG. 11, a first synthesizer 51 includes a voltage controlled oscillator (VC
O1) Switch (S) for controlling ON / OFF of 512
W) 511, voltage controlled oscillator (VCO1) 512, PL
L circuit (PLL1) 513, low-pass filter 514,
It comprises capacitors C2, C3, C4, coils L1, L2, resistors R1, R2, R3.

Here, a control signal S1 for controlling ON / OFF of the voltage controlled oscillator 512 is applied to the switch 511, and a common signal data D, clock CK, data setting signal LE, A control signal C including a data setting signal LE, a battery saving signal BS1, a lock detection signal LD1, and a reference clock SYSCK including a reference frequency is added. The resistors R1, R2, and R3 form an attenuator 515.

Similarly, the second synthesizer 52 includes a switch (SW) 521 for controlling ON / OFF of a voltage controlled oscillator (VCO 2) 522 and a voltage controlled oscillator (VCO 2).
2) 522, PLL circuit (PLL2) 523, low-pass filter 524, capacitors C2 ', C3', C4 ',
It comprises coils L1 ', L2' and resistors R1 ', R2', R3 '.

Here, a control signal S1 'for controlling ON / OFF of the voltage controlled oscillator 522 is applied to the switch 521, and a common signal data D, clock CK, and data setting signal LE are applied to the PLL circuit 523. , A data setting signal LE, a battery saving signal BS2, a lock detection signal LD2, and a control signal C 'including a reference clock SYSCK including a reference frequency. Also,
The resistors R1 ', R2', R3 'constitute an attenuator 525.

The synthesizer switching circuit 53 includes a control switch (SW) 531 for the amplifiers 532 and 533, a control switch (SW) 534 for the amplifiers 535 and 536, an amplifier 532, 533, 535 and 536, and a switch (SW).
537, comprising coils L3 and L3 '.

Here, a first local signal LO output from the first synthesizer 51 is applied to the control switch 531.
1 is selected, and the control switch 5
A selection signal S2 ′ for selecting the second local signal LO2 output from the second synthesizer 52 is applied to 34, and when the selection signal S2 is applied, the amplifiers 532 and 53
3, the amplifiers 532 and 533 are turned on, the switch 537 is switched to select the output of the amplifier 533, and the first local signal LO1 output from the first synthesizer 51 is changed to the local signal L.
O, and when the selection signal S2 'is added, power is supplied to the amplifiers 535 and 536,
6 is turned on, and the switch 537 is
6 is switched to select the output, and the second local signal LO2 output from the second synthesizer 52 is output as the local signal LO.

The power supply 54 includes a constant voltage power supply (Reg1) 541 for supplying power to the first synthesizer 51 and a constant voltage power supply (Reg) for supplying power to the second synthesizer 52.
1 ') 542, a constant voltage power supply (Reg2) 543 for supplying power to the synthesizer switching circuit 53, a capacitor C1,
C1 ′, C5 and a constant voltage power supply (Reg)
1) ON of the constant voltage power supply (Reg1) 541
/ OFF control signal P1, constant voltage power supply (Reg1 ') 54
2 includes ON / OF of a constant voltage power supply (Reg 1 ′) 542.
The ON / OFF control signal P2 of the constant voltage power supply (Reg2) 543 is added to the F control signal P1 ′ and the constant voltage power supply (Reg2) 543.

The coils L1, L2, L3, L
1 ', L2', and L3 'are inserted for isolation from the power supply 54. These coils are used to increase the impedance with respect to the local signals LO1 and LO2.

FIG. 12 is a timing chart showing the operation of the local signal generator 5 shown in FIG.

In FIG. 12, (a) of FIG. 12 shows a slot configuration of a portable telephone employing the local signal generator 5. That is, this mobile phone is configured to communicate with, for example, a base station (not shown) in units of eight slots, four transmission slots and four reception slots.
2 (b) shows a frame signal for realizing this communication.

FIG. 12C shows the voltage controlled oscillator (VCO1) of the first synthesizer 51 shown in FIG.
FIG. 12D shows the ON / OFF control signal S1 of the voltage controlled oscillator (VCO2) 522 of the second synthesizer 52 shown in FIG.

FIG. 12E shows a selection signal S1 for selecting the first local signal LO1 applied to the control switch 531 of the synthesizer switching circuit 53 shown in FIG.
FIG. 12F shows a selection signal S2 ′ for selecting the second local signal LO2 applied to the control switch 534 of the synthesizer switching circuit 53 shown in FIG.

FIG. 12G shows a PLL circuit (PLL1) 51 of the first synthesizer 51 shown in FIG.
3 is applied to the frequency division ratio setting signal (CK, except BS1, CK,
D, LE), and FIG. 12H shows the PLL circuit (PLL2) 52 of the second synthesizer 52 shown in FIG.
3, the frequency division ratio setting signal (CK except BS2,
D, LE).

FIG. 12I shows a PLL circuit (PLL1) 51 of the first synthesizer 51 shown in FIG.
3 shows a battery saving signal BS1 added to 3;
(J) of FIG. 12 shows the battery saving signal BS2 applied to the PLL circuit (PLL2) 523 of the second synthesizer 52 shown in FIG.

As is apparent from FIG. 12, in the local signal generator 5 of this portable telephone, the voltage controlled oscillator (VCO1) 512 of the first synthesizer 51 and the voltage controlled oscillator (VCO2) 522 of the second synthesizer 52
Are operating at the same time. In this time zone, in order to secure the wireless performance of this mobile phone, that is, spurious, sensitivity, selectivity, etc., the voltage-controlled oscillator of the first synthesizer 51 ( VCO1) 512 and the second
Voltage controlled oscillator (VCO2) 52 of synthesizer 52
It is necessary that isolation between the two is established.

In the local signal generator 5 shown in FIG. 11, there are various routes for deteriorating the isolation between the circuits. Specific examples of the routes for deteriorating the isolation are shown in FIG.

That is, the first route of the isolation deterioration is performed by the first synthesizer 51 via the power supply 54.
This is a route in which the output of the voltage-controlled oscillator (VCO1) 512 and the output of the voltage-controlled oscillator (VCO2) 522 of the second synthesizer 52 affect each other.

The second route of the isolation degradation is the PLL circuit (PLL) of the first synthesizer 51.
1) A voltage controlled oscillator (VCO) via the control line 513
1) A route where the output of 512 leaks and a route where the output of the voltage controlled oscillator (VCO2) 522 leaks via the control line of the PLL circuit (PLL2) 523 of the second synthesizer 52.

The third route of the isolation degradation is a route connected by the wiring patterns of the first synthesizer 51 and the second synthesizer 52, the wiring pattern of the synthesizer switching circuit 53, a shield plate (not shown), and the like.

The fourth route of the isolation degradation is the P route of the first synthesizer 51 via the power supply 54.
This is a route that leaks to the LL circuit (PLL1) 513 and the PLL circuit (PLL2) 523 of the second synthesizer 52.

In order to prevent the above-mentioned isolation deterioration, in the local signal generator 5 shown in FIG. 11, it is necessary to block each circuit at a high frequency by a shield structure. FIG.
Shown in

FIG. 14 shows only the portion related to the first synthesizer 51 of the local signal generator 5 shown in FIG. 11, and in FIG. 14, blocks A and B surrounded by a chain line. And C are isolation blocks required to prevent isolation degradation.

Here, the block A includes a part of the voltage controlled oscillator (VCO1) 512 and the PLL circuit (PLL1) 513 of the first synthesizer 51, and the block B includes the PLL circuit (PLL1) of the first synthesizer 51. ) 513
, Low-pass filter 514, attenuator (AT
T) 515, and the block C includes the amplifiers 532 and 533 of the synthesizer switching circuit 53.

In this case, when the local signal generating section 5 is formed on a substrate, it is necessary to lay out a circuit in consideration of the blocks A, B, and C. Also, when a shield structure is formed. It is necessary to form the blocks in consideration of the blocks A, B, and C.

Now, as the above shield structure,
A shield structure as shown in FIG. 15 is known.

That is, the shield structure shown in FIG. 15A is different from the substrate 10 on which the radio circuit shown in FIG.
Case 1 whose upper part is parallel to the substrate 10
2 and a voltage-controlled oscillator (VCO 1) 5 of the first synthesizer 51 of the local signal generator 5.
12 including PLL circuit 12 and PLL circuit (PLL1) 513
1 are separated by a separation wall 12a.

In the shield structure shown in FIG. 15B, the upper portion of the entire substrate 10 on which the radio circuit shown in FIG. The voltage controlled oscillator (VCO) of the synthesizer 51
1) First shield case 14 protruding upward only in circuit portion 11 including 512 and PLL circuit (PLL1) 513
And the first synthesizer 51
Voltage controlled oscillator (VCO1) 512 and PLL circuit (P
(LL1) 513 is configured by doubly shielding the circuit portion 11 including the second shield case 13.

The shield structure shown in FIG. 15 (c) is similar to the voltage-controlled oscillator (VCO1) 512 of the first synthesizer 51 of the local signal generator 5 shown in FIG.
The circuit portion 11 including the LL circuit (PLL1) 513 is mounted on the back side of the substrate 10, and the other portion of the radio circuit shown in FIG. 10 is mounted on the front side of the substrate 10, and the entire front side of the substrate 10 is first. A voltage-controlled oscillator (VCO 1) 5 on the back side of the substrate 10
12 including PLL circuit 12 and PLL circuit (PLL1) 513
The mounting portion 1 is shielded by a second shield case 15.

In the shield structure shown in FIG. 15D, a part of the radio circuit shown in FIG. 10 is mounted on the front side of the substrate 10, and the first synthesizer of the local signal generator 5 of the radio circuit is provided. A portion including a voltage-controlled oscillator (VCO1) 512 and a PLL circuit (PLL1) 513 is mounted on the back side of the substrate 10, the entire front side of the substrate 10 is shielded by the first shield case 16, and the entire back side of the substrate 10 is shielded. Is shielded by a second shield case 17, and the voltage-controlled oscillator (VCO1) 512 and the PLL circuit (PL
L1) The mounting portion of the circuit portion 11 including 513 is separated from the separation wall 1
7a.

[0038]

As described above, in order to obtain isolation between certain circuit blocks, it is necessary to divide the circuit blocks to form a shield structure. As shown in FIG. 15B, a double shield structure may be employed, or as shown in FIG. 15A or FIG.
7A, or a structure in which a circuit block is separated on the front and back of the substrate 10 as shown in FIG.

However, the shield structure adopting the double shield structure or separating the circuit block on the front and back of the substrate 10 has a complicated structure, the number of parts increases, and the assembly becomes complicated. In addition, there is a problem that more than one type of shield making is required,
In the structure where the separation wall is separated, the separation wall is made of a separate piece, or the structure is brought into contact between the ground and the shield top plate.In this case, too, the number of parts increases, the assembly becomes complicated, and the weight of the entire device is increased. However, there is a problem that more molds are required for making the shield.

There is also a method of generating a shield structure by a combination of molding and plating. However, in this method, the connection space is large and the mold for molding is expensive, leading to an increase in the cost of the entire apparatus. was there.

Accordingly, an object of the present invention is to provide a shield structure of a wireless device which is inexpensive, has a simple structure, can be reduced in weight, and can reliably shield necessary parts.

[0042]

In order to achieve the above object, according to the present invention, in a shield structure of a wireless device having at least a board on which a high-frequency circuit is mounted, a shield plate is attached to the board. A part of the shield plate is cut out, the cut-out portion is bent toward the substrate, and the bent end is connected to a ground point of the substrate.

According to a second aspect of the present invention, in the first aspect of the present invention, the shield plate is made of sheet metal,
The cut-out portion is integrally formed from the sheet metal by press working.

According to a third aspect of the present invention, in the first aspect of the present invention, the cutout portion is selectively formed near a signal output portion of the high-frequency circuit, and the cutout portion is formed in the signal output portion of the high-frequency circuit. It is connected to a ground point of the substrate in the vicinity.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the cutout portion is formed between circuits requiring isolation, and the cutout portion is bent toward the substrate to form the bent end. Is connected to a grounding point of the substrate to form a slit-shaped shield structure between circuits requiring the isolation.

According to a fifth aspect of the present invention, in the first aspect of the present invention, a separately formed shield box is inserted into a hole formed by bending the cutout toward the substrate. It is characterized in that a circuit requiring isolation is mounted therein.

According to a sixth aspect of the present invention, in the first aspect, the cutout portion is formed at a corner of the substrate, and the cutout portion is formed by bending the cutout portion toward the substrate. A circuit that requires isolation is mounted in the region of (1).

According to a seventh aspect of the present invention, in the first aspect of the present invention, the high frequency circuit includes a reference oscillator, a voltage controlled oscillator, and a PLL circuit.

According to the present invention, in a shield structure of a radio having at least a substrate on which a high-frequency circuit is mounted, a plurality of shield plates for separating a mounting portion of the high-frequency circuit are attached to the substrate. At least one part of the plurality of shield plates is cut out, the cutout portion is bent toward the substrate, and the bent end is connected to a ground point of the substrate.

[0050]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a shield structure of a radio device according to an embodiment of the present invention.

According to the shield structure of a radio device according to the present invention, a shield plate made of sheet metal is attached to at least a substrate on which a high-frequency circuit is mounted, a part of the shield plate is cut out, and the cutout is bent toward the substrate. Then, a method of connecting the bent end to the ground point of the substrate is adopted.

According to such a method, the shield structure can be formed only by a simple press working.
The number of parts is small, the weight is low, and the necessary circuit parts can be shielded reliably, providing a shield structure that is particularly suitable for radio equipment such as mobile phones that require miniaturization, weight reduction, and cost reduction. can do.

FIG. 1 is a schematic view showing a circuit board of a radio circuit of a portable telephone to which a shield structure of a radio device according to the present invention is applied.

In FIG. 1, the shield plate is 2
FIG. 1A shows a case of a three-piece configuration (FIG. 1A), a three-piece configuration (FIG. 1B), and a one-piece configuration (FIG. 1C).

That is, the structure shown in FIG. 1 shows the shield structure in the substrate of the radio circuit of the portable telephone described in detail with reference to FIGS. 10 and 11. In the shield structure shown in FIG. The voltage-controlled oscillator (VCO) of the second synthesizer 52 of the radio circuit on the substrate 100
2) Shield plate 300 provided corresponding to a portion where 522, a PLL circuit (PLL2) 523, and a circuit including amplifiers 535 and 536 of synthesizer switching circuit 53 are mounted.
And a shield plate 200 disposed in correspondence with a portion on which the other circuit of the wireless circuit is mounted. Here, the outer edges of the shield plates 200 and 100 are bent toward the substrate 100 and
00 are connected to the grounding point 00, respectively, forming a shield case.

In the shield structure shown in FIG. 1B, the voltage controlled oscillator (VCO 1) 512 of the first synthesizer 51 of the radio circuit on the substrate 100
L circuit (PLL1) 513, synthesizer switching circuit 53
And a voltage-controlled oscillator (VCO) of the second synthesizer 52 of the radio circuit.
2) Shield plate 300 provided corresponding to a portion where 522, a PLL circuit (PLL2) 523, and a circuit including amplifiers 535 and 536 of synthesizer switching circuit 53 are mounted.
And a shield plate 500 provided corresponding to a portion where the other circuit of the wireless circuit is mounted. Also in this shield structure, the outer edges of the shield plates 300, 400, and 500 are bent toward the substrate 100 and connected to the ground point of the substrate 100, thereby forming shield cases.

Further, the shield structure shown in FIG. 1C has a one-piece shield structure with a shield plate 600 provided corresponding to the entire substrate 100. Includes a voltage-controlled oscillator (VCO1) 51 of the first synthesizer 51 of the radio circuit.
2, a circuit including the PLL circuit (PLL1) 513, the amplifiers 532 and 533 of the synthesizer switching circuit 53, and the voltage controlled oscillator (VCO2) 522 of the second synthesizer 52;
A slit 600a for isolating the PLL circuit (PLL2) 523 and a circuit including the amplifiers 535 and 536 of the synthesizer switching circuit 53 is provided. Also in this shield structure, the outer edge of the shield plate 600 is bent toward the substrate 100 and connected to the ground point of the substrate 100 to form a shield case.

Now, the shield structure of the wireless device according to the present embodiment will be described with reference to FIGS. 1 (a), 1 (b) and 1 (c).
Shield plates 200, 300, 400, 500, 6
If it is necessary to shield at a specific portion of any of the shield plates of No. 00, a cutout is formed in this portion, the cutout is bent toward the substrate 100, and the tip of the cutout is grounded to the substrate 100. By connecting to a part, a shield of a desired part is realized.

FIG. 2 is a diagram showing a case where the shield structure according to the first embodiment of the present invention is applied to the shield structure shown in FIG.

In FIG. 2, a voltage controlled oscillator (VCO)
1) Between 512 and switch (SW) 537, and between voltage controlled oscillator (VCO1) 512 and amplifiers 532, 533
It shows the case where isolation is required between and
In this case, as shown in FIG.
A cut-out portion 201 having a part connected to the shield plate 200 is formed between the voltage-controlled oscillator (VCO1) 512 and the switch (SW) 537, and the voltage-controlled oscillator (VCO1) 512 and the amplifiers 532, 533 The cutouts 202 and 203, which are partially connected to the shield plate 200, are formed between the cutouts 201 and 20.
2 and 203 are bent toward the substrate 100 at the connection portion with the shield plate 200 as shown in FIG. 2B, and the tips, that is, the feet 201a, 202a, and 203a are attached to the substrate 1
Connect to ground point on 00.

Here, the cutout portions 201, 202, 20
The connection between the third feet 201a, 202a, and 203a and the ground point (ground pattern) on the substrate 100 is made by contact with the ground point,
Techniques such as soldering and through holes can be adopted.

In the above structure, the shield plate 20
At 0, holes are formed for the cutout portions 201, 202, and 203. For example, when the shield frequency is λ, the width of the cutout portions 201, 202, and 203 is reduced to approximately λ / 100. This will not affect the shielding effect of this hole.

FIG. 2 shows a case where the shield structure of the present invention is applied to the shield plate 200 in the shield structure shown in FIG. 1A. Similarly, the shield plate 300, the shield plates 300, 400, and 500 in FIG. 1B, and the shield plate 600 in FIG. 1C can be selectively shielded by forming cutouts at desired locations. it can.

When the shield structure shown in FIG. 1A is used, the shield plate 200, the voltage controlled oscillator (VCO1) 512 of the first synthesizer 51, the PLL circuit (PLL1) 513, the synthesizer switching circuit 53 532, 533 and the switch (SW) 537 are capacitively coupled, and as a result, the voltage controlled oscillator (VCO1) 512
And the output of the PLL circuit (PLL1) 513 leak through the shield plate 200.

FIG. 3 is a diagram showing a state of capacitive coupling via the shield plate 200 when the shield structure shown in FIG. 1A is employed.

In FIG. 3, the shield plate 200 and the voltage controlled oscillator (VCO1) 512 are coupled by a stray capacitance Cf1, and the shield plate 200 and the PLL circuit (PLL1) 5 are connected.
13 is coupled with the stray capacitance Cf2, and the shield plate 20
0 and the amplifiers 532 and 533, respectively.
f3 and Cf4, and the stray capacitance Cf5 connects between the shield plate 200 and the switch (SW) 537.

In this case, the shield plate 200 is moved to the points PO1, PO2, PO3, PO
By grounding at 4, the isolation between the circuits can be realized, and the output of the voltage controlled oscillator (VCO1) 512 and the output of the PLL circuit (PLL1) 513 can be effectively prevented.

FIG. 4 is a diagram showing a shield structure according to a second embodiment of the present invention.

In the second embodiment, the shield plate 70
0, a cutout part of which is partially connected to the shield plate 700 is formed, and the cutout parts 701, 702, 703, 70
4 is bent to the substrate side and its tip is connected to the ground point of the substrate in the same manner as in the first embodiment, but in the second embodiment, a cutout formed in the shield plate 700 is formed. The first embodiment differs from the first embodiment in that a shield box 800 formed of another piece is inserted into a hole formed by bending 701, 702, 703, 704 toward the substrate.

That is, in the second embodiment shown in FIG.
0 is formed, and the cutout portion 7 is formed.
01, 702, 703, and 704 are bent toward the substrate (not shown), and their ends are connected to the ground point of the substrate.

Here, the cutout portions 701, 702, 70
3, 704 and the substrate are connected by cutouts 701, 70
Feet 701a, 7 provided at the tips of 2, 703, 704
This is performed by soldering 02a, 703a, and 704a to a substrate.

The connection between the shield plate 700 and the substrate is also made by bending the outer edge of the shield plate 700 and soldering a leg 700a formed at the tip thereof.

Shield box 8 formed of another piece
No. 00 is inserted into the hole formed by the cutout portion 701 and the hole 700a formed on the side of the shield box 800 by the protrusion 700a formed on the cutout portion 703.
Is performed by fitting.

Further, the connection of the shield box 800 to the substrate is performed by using the feet 800 formed on the shield box 800.
This is performed by soldering a to a substrate.

In the second embodiment, a cutout is formed at an arbitrary position on shield plate 700, and shield box 8 of another piece inserted into this cutout is formed.
By mounting a required circuit in 00, effective shielding is possible.

If a plurality of cutouts are formed on the shield plate 700, a plurality of circuits can be shielded.
In this case, the feet can be soldered at the same time.

That is, according to the second embodiment, 1) it is possible to selectively shield any place. 2) The space is only required to be twice the thickness of the shield sheet metal. 3) Another piece The shield box 800 is mounted using the side hole 800a, but the feet 800a of the shield box 800 can be soldered to the board and can produce a stable ground.

It is also possible to form a shield structure by combining the structure of the second embodiment with the structure of the first embodiment.

FIG. 5 shows the slit 6 shown in FIG.
It is a figure which shows 3rd Embodiment of this invention using 00a.

In the fifth embodiment, a slit 600a is formed in a shield plate 600. Then, isolation between circuits is realized by the slit 600a. FIG. 6 shows a detailed structure of the slit 600a according to the third embodiment.

That is, as shown in FIG. 6A, cutouts 601, 602, and 603 are formed in the shield plate 600 so that a part thereof is connected to the shield plate 600. And
As shown in FIG. 6B, the cutouts 601 and 6
02 and 603 are connected to the shield plate 600 by the substrate 10
0, and cut out portions 601, 602, 60
The third feet 601a, 602a, 603a are soldered to a grounding point such as a grounding pattern on the substrate 100.

Incidentally, according to the structure of FIG.
A cutout for forming the feet 601b, 602b, and 603b is formed on both sides of the cutout 0a. If the size of the cutout is set according to the shield frequency, the cutout deteriorates the shield characteristics. Never.

According to such a structure, the shielded slit 600a can be formed by a simple structure, and isolation between circuits on both sides of the slit 600a can be easily realized.

FIG. 7 is a diagram showing another detailed structure of the slit 600a shown in FIG.

The structure shown in FIG.
02, 603, so that the tips of the feet 601a, 602a, 603a coincide with the bent portions.
6 is different from the structure shown in FIG. 6 only in that 2,603 are formed.

According to such a structure, there is a disadvantage that a notch is formed. However, as shown in FIG.
Foot 601b, 602b, 60 on both sides of slit 600a
There is no cutout for forming 3b.

FIG. 8 shows the slit 6 shown in FIG.
It is a figure showing a modification of a 3rd embodiment of this invention using 00a.

In the structure shown in FIG. 8, a slit 600a is formed in
The structure shown in FIG. 8 is the same as the structure shown in FIG. 6 in that the isolation between circuits is realized by 00a, but the structure shown in FIG. Shield plate 600
Slit 100a similar to slit 600a formed in
To form

According to such a structure, the shielded slit 600a can be formed by a simple structure, similarly to the structure shown in FIG.
Isolation between circuits on both sides of Oa can be easily realized.

FIG. 9 is a view showing a modification of the second embodiment of the shield structure of the present invention.

The embodiment of FIG. 9 is suitable for shielding a circuit mounted at a corner of a substrate. This figure 9
In the embodiment shown in FIG. 1, a cutout part of which is partially connected to the shield plate 900 is formed at a corner of the shield plate 900, and the cutout pieces 901 and 902 are bent toward the substrate side to form a shield region. A circuit requiring isolation is mounted in this shield region.

With such a structure, isolation between circuits can be realized with a simple structure.

[0093]

As described above, according to the present invention, 1) the shield structure can be easily formed by press working or the like, so that the shield can be realized by the simple structure. 2) The number of parts is small and the man-hour for forming the shield is reduced. 3) Space is small because there is no case contact or use of a frame. 4) Solder mounting allows secure and easy connection. 5) Shield material can be made thinner. The effect is that weight reduction is possible.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a substrate of a wireless circuit of a mobile phone to which a shield structure of a wireless device according to the present invention is applied.

FIG. 2 is a diagram showing a case where the shield structure according to the first embodiment of the present invention is applied to the shield structure shown in FIG.

FIG. 3 is a diagram showing a state of capacitive coupling via a shield plate 200 when the shield structure shown in FIG. 1A is employed.

FIG. 4 is a diagram showing a shield structure according to a second embodiment of the present invention.

FIG. 5 is a view showing a third embodiment of the present invention using the slit 600a shown in FIG. 1 (c).

FIG. 6 is a diagram showing a detailed structure of a slit 600a shown in FIG.

FIG. 7 is a diagram showing another detailed structure of the slit 600a shown in FIG.

FIG. 8 is a diagram showing a modification of the third embodiment of the present invention using the slit 600a shown in FIG. 1 (c).

FIG. 9 is a view showing a modified example of the fourth embodiment of the shield structure of the present invention.

FIG. 10 is a schematic block diagram illustrating a main part of a wireless circuit of the mobile phone.

11 is a circuit diagram showing a detailed configuration of a local signal generator 5 shown in FIG.

FIG. 12 is a timing chart illustrating the operation of the local signal generator 5 shown in FIG.

FIG. 13 is a diagram for explaining a route of isolation degradation in the local signal generator 5 shown in FIG.

FIG. 14 is a diagram illustrating an example of a separation block necessary for preventing the above-described isolation degradation in the local signal generation unit 5 illustrated in FIG. 11;

FIG. 15 is a view showing an example of a conventional shield structure in a mobile phone.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Antenna 2 Transmission / reception switch 3 Receiver 4 Transmitter 5 Local signal generator 51 First synthesizer 52 Second synthesizer 53 Synthesizer switch 54 Power supply 512 Voltage control transmitter (VCO1) 513 PLL circuit (PLL1) 522 Voltage control Transmitter (VCO2) 523 PLL circuit (PLL2) 532, 533, 535, 536 Amplifier 537 Switch 100 Substrate 200, 300, 400, 500, 600, 700, 9
00 Shield plate 800 Shield box 201, 202, 203 Cutouts 201a, 202a, 203a Feet (cutout tip) 701, 702, 703, 704 Cutout 701a, 702a, 703a, 704a Foot (cutout tip) 100a, 600a Slit 601, 602, 603 Cutout 601 a, 602 a, 603 a Leg (tip of cutout) 901, 902 Cutout

Claims (8)

[Claims] 1. A shield structure of a wireless device having at least a substrate on which a high-frequency circuit is mounted, wherein a shield plate is attached to the substrate, a part of the shield plate is cut out, and the cutout is bent toward the substrate side. A shield structure for a wireless device, wherein a bent end is connected to a ground point of the substrate. 2. The shield structure according to claim 1, wherein the shield plate is made of a sheet metal, and the cutout is integrally formed from the sheet metal by press working. 3. The cut-out section is selectively formed near a signal output section of the high-frequency circuit, and is connected to a ground point of the substrate near a signal output section of the high-frequency circuit. A shield structure for a wireless device according to claim 1. 4. The isolation portion is formed between circuits requiring isolation, and the isolation portion is formed by bending the cutout portion toward the substrate and connecting the bent end to a ground point of the substrate. 2. A shield structure for a wireless device according to claim 1, wherein a slit-like shield structure is formed between circuits requiring the following. 5. Inserting a separately formed shield box into a hole formed by bending the cutout toward the substrate, and mounting a circuit requiring isolation in the shield box. The shield structure for a wireless device according to claim 1, wherein: 6. The circuit according to claim 1, wherein the cutout is formed at a corner of the substrate, and a circuit that requires isolation is mounted in a corner area of the substrate formed by bending the cutout toward the substrate. The shield structure for a wireless device according to claim 1, wherein: 7. The shield structure according to claim 1, wherein the high-frequency circuit includes a reference oscillator, a voltage controlled oscillator, and a PLL circuit. 8. A shield structure of a wireless device having at least a substrate on which a high-frequency circuit is mounted, wherein a plurality of shield plates separating a mounting portion of the high-frequency circuit are attached to the substrate, and at least one of the plurality of shield plates is provided. A shield structure for a wireless device, wherein a part of the shield is cut out, the cut-out portion is bent toward the substrate, and the bent end is connected to a ground point of the substrate.