JP2007180237A - Circuit board and transceiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit board and a transceiver which are strong against shocks, can be manufactured at low cost, also is strong against noise infiltration, and can prevent diffusion. <P>SOLUTION: In the circuit board 34, a shielding case 11, having a polygon in a planar shape, is jointed onto a land 12 having a polygon in a contour with a solder. A slanted cutout 13 is provided at the corner of the land 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a circuit board and a portable wireless device having a shield case for preventing intrusion or diffusion of noise.

Conventionally, PDA (Personal Digital) with mobile phone and wireless function
There are cases in which a circuit board on which an IC package that constitutes a control unit and a radio unit is mounted is provided in a case of a portable radio device such as an assistant. These IC packages are generally covered with a shield case in order to prevent the intrusion of noise from the outside or the diffusion of noise to the outside.
Specifically, a shield case is placed on a reference potential pattern land formed on a circuit board so as to surround the IC package, and soldered (for example, see Patent Document 1).
JP-A-7-240591

By the way, the portable wireless device is frequently carried, and an impact load due to dropping or the like is easily applied to the shield case or the circuit board.
Especially when a shield case with a rectangular outer shape is used, not only the impact load acts on the corner of this shield case, but also the distance between the corner of the shield case and the corner of the reference potential pattern land is shielded. Since the distance is longer than the distance between one side of the case and one side of the reference potential pattern land, the solder diffuses and the fillet shape cannot be secured sufficiently.
If the fillet shape is not sufficiently formed, the bonding strength will be weakened. Therefore, if an impact is applied to the shield case or the circuit board, there is a risk of cracks occurring at the joint between the shield case and the circuit board, or the shield case may be peeled off. There is a problem that there is.
Although it is conceivable to increase the amount of solder applied to the reference potential pattern land and ensure a sufficient fillet shape, it is difficult to say that it is a good solution because the manufacturing cost increases.
In addition, when the shield case is peeled off, the shielding performance against the IC package is deteriorated, so that there is a problem that the intrusion and diffusion of noise is allowed and the performance of the portable wireless device may be lowered.

  Accordingly, the present invention provides a circuit board and a portable wireless device that are resistant to impact, can be manufactured at low cost, are resistant to noise intrusion, and can prevent diffusion.

In order to solve the above problems, the invention described in claim 1 includes a reference potential pattern land having an outer shape of a polygon and a shield case having a polygonal shape of a plane on the reference potential pattern land. A circuit board to be soldered, wherein a notch is provided at a corner of the reference potential pattern land.
With this configuration, it is possible to shorten the distance between the corner of the shield case and the corner of the reference potential pattern land, prevent the solder from being diffused, and ensure a proper fillet shape for the solder. Further, the reference potential pattern land can be easily improved by changing the resist shape without changing the shield case.

The invention described in claim 2 is characterized in that an IC package constituting a wireless unit or a control unit is mounted on a circuit board in a reference potential pattern land having a polygonal outer shape.
By configuring in this way, the wireless unit and the control unit can be covered with a strong shield case, and the intrusion of noise from the outside and the diffusion of noise to the outside can be surely prevented.

The invention described in claim 3 is a portable wireless device including the circuit board according to claim 1 or 2 in a housing.
By using such a circuit board, it is suitable for a portable wireless device such as a cellular phone, which is used in a severe situation with high frequency of use and impact.

  According to the first aspect of the present invention, it is possible to shorten the interval between the corner of the shield case and the corner of the reference potential pattern land, prevent the diffusion of the solder, and ensure a proper fillet shape for the solder. . In addition, since the reference potential pattern land can be easily improved by changing the resist shape without changing the shield case, it is resistant to impact and can be manufactured at low cost.

  According to the second aspect of the present invention, since the wireless unit and the control unit are covered with a strong shield case, it is possible to reliably prevent the intrusion of noise from outside and the diffusion of noise to the outside. There is an effect of improving the performance.

  According to the invention described in claim 3, if the circuit board having the shield case according to claim 1 or 2 is used in a portable wireless device provided in the housing, even if an impact is applied by dropping or the like, the shield is provided. Since peeling of the case can be prevented, there is an effect that noise from the outside can be surely prevented and noise can be prevented from diffusing to the outside and the performance of the portable wireless device can be improved.

1 to 6 show a first embodiment of the present invention.
As shown in FIG. 1, the portable electronic device 1 includes a second housing 5 having a main display 4 in a first housing 3 having a plurality of operation keys such as a numeric keypad 81, a cursor key 82, or a function key 83. This is a so-called foldable mobile phone that is pivotally supported via a hinge portion 6 so as to be opened and closed.
The first housing 3 includes a circuit board 34 inside a rear case 32 formed in a box shape. An antenna 30 is disposed on the front end side of the rear case 32, and the antenna 30 is connected to a wireless communication unit (not shown).

A front case 31 is provided at the opening of the rear case 32 so as to cover the circuit board 34 and the antenna 30. In the front case 31, the key operation unit 2 including the plurality of operation keys is exposed.
On both sides of the base end of the front case 31 and the rear case 32, bearing portions 9A and 9B of a hinge portion 6 that pivotally supports the second housing 5 so as to be openable and closable are provided so as to protrude.
The bearing portions 9A and 9B are provided with first hole portions 91 and 91 into which end portions of the cylindrical rotary shaft 18A and the hinge unit 18B provided in the second housing 5 are inserted, respectively.
In addition, on the base side of the first housing 3, a housing recess 93 for housing the protruding portion 16 provided on the second housing 5 is formed.

The second housing 5 that is pivotally supported by the first housing 3 is provided with a front case 51 in which the main display 4 is exposed and arranged on the inner surface, and the sub display 14 is exposed and arranged on the outer surface.
Inside the front case 51, a circuit board 55 for displaying the main display 4 and the sub display 14 on the base side of the front case 51 is disposed adjacent to the sub display 14. The circuit board 55 is provided with an LCD-side connector receiving portion 56 connected to the second connector 70, and the camera module 15 is housed on the base side of the front case 51 adjacent to the circuit board 55.

On the surface side of the base portion of the front case 51, a protruding portion 16 of the hinge portion 6 is provided protruding toward the first housing 3 side, and a part of the cylindrical rotating shaft 18A and the hinge unit 18B is a protruding portion. The protrusion 16 is provided so as to protrude from both ends of the protrusion 16. The rotary shaft 18A has a second hole 92 therein. The second hole portion 92 has a size that allows the cable portion 71 connected to the second connector 70 to be inserted therethrough.
With the protrusion 16 fitted in the storage recess 93, both ends of the rotary shaft 18A and the hinge unit 18B are inserted into the first holes 91A and 91B, respectively, and supported by the bearing portions 9A and 9B. Thereby, the 1st housing | casing 3 and the 2nd housing | casing 5 are supported so that opening and closing is possible.

A rear case 52 is provided so as to cover the opening of the front case 51. A window 53 for the sub display 14 is provided in the upper part of the rear case 52, and a window 54 through which the lens 15a of the camera module 15 is exposed is formed in the lower part.
The circuit board 34 and the circuit board 55 described above are connected by the connection cable 7. The connection cable 7 includes a first connector (not shown) connected to a first connector receiving portion (not shown) on the circuit board 34 side, a second connector 70 connected to the LCD side connector receiving portion 56, and these second connectors 70. And a cable portion 71 for connecting a first connector (not shown).
The cable portion 71 is bundled, and the tip opposite to the second connector 70 side passes through the second hole portion 92 and is connected to the circuit board 34 side.

As shown in FIGS. 2 to 5, on a circuit board 34, a semiconductor integrated circuit such as an LSI (LSI: Large Scale Integration) that constitutes a circuit, an electronic component 20 such as a passive component such as a resistor, a capacitor, and a coil, An IC package 10 is mounted.
The IC package 10 includes a radio unit and a control unit such as a PLL (PLL: Phase Locked Loop) and a VCO (VCO: Voltage Controlled Oscillator), a component that handles high frequencies such as a capacitor coil and an LCR, a modulator, and a SAW filter. (SAW: Surface Acoustic Wave) It is comprised by the components used for a modulation circuit.

A shield case 11 is provided on the circuit board 34 so as to cover the IC package 10. The shield case 11 is a sheet metal member having a rectangular outer shape, and is formed by bending the side walls 11b, 11b, 11c, and 11c at right angles from each side of the rectangular flat portion 11a. The flat portion 11a is provided with holes 11d and 11e for weight reduction.
Further, as shown in FIG. 5, the abutting portions of 11b and 11c have a shape cut out at right angles to the inside when viewed from the upper surface of the shield case 11, and the corner portions 11f and 11g of the side walls 11b and 11c are It protrudes toward the outside.

  The shield case 11 is placed on the land 12 arranged around the IC package 10 toward the circuit board 34 (indicated by an arrow A), and is joined to the land 12 by the solder 22 applied in advance. It absorbs high frequency noise emitted from the IC package 10 and prevents noise from entering the IC package 10 from the outside.

The lands 12 are formed by thin metal films arranged at six locations along the periphery of the shield case 11 and connected to the ground (reference potential).
The lands 12 are formed by arranging substantially L-shaped L-shaped lands 12a arranged at four corners and I-shaped lands 12b arranged on the side sides at substantially equal intervals. There are two types of L-shaped lands 12a, one with a long straight line portion and one with a short straight line portion. The one with a short straight line portion is the same as one with a long straight line portion. Only will be described.
Diagonal cutouts 13 that are cut diagonally are provided at the corners of the L-shaped land 12a, and the distance L1 between the diagonal cutout 13 of the L-shaped land 12a and the corners 11f and 11g of the shield case 11 is L-shaped. The distance L2 between the side portion of the land 12a and the side portion of the shield case 11 is set at an appropriate distance that is substantially equivalent.
Also, as shown in FIG. 4, on each land 12, a plate-like solder 22 formed slightly larger than the shape of each land 12 is applied in advance to a circuit board 34 (indicated by an arrow B). After placing the shield case 11 on the land 12, the solder 22 is melted (reflowed) by applying heat to each land 12 and a portion corresponding to each land 12 of the shield case 11, and the two are joined.

Here, as shown in FIG. 6, the melted solder 22 diffuses over the entire surface of the land 12 due to the surface tension peculiar to the liquid, and is in a raised state. The raised solder joint part sticks to the side wall of the shield case 11 to form a fillet-shaped part 22a.
When the distance L1 between the oblique cutout portion 13 of the L-shaped land 12a and the corner portion 11f of the shield case 11 is long, the solder 22 is diffused in a wide area, and the fillet-shaped portion 22a has a height H of the fillet-shaped portion 22a. When L1 is short, the height 22 becomes high without the solder 22 being diffused wastefully.
That is, the fillet-shaped portion 22a can set the height L to an appropriate height by setting the distance L1 to an appropriate length, and can obtain sufficient strength.
Incidentally, the thickness of the solder 22 used for joining the shield case 11 covering the IC package 10 and the land 12 is generally standardized. Therefore, in the first embodiment of the present invention, when the standard thickness of the solder 22 is taken into consideration, the distances L1 and L2 between the land 12 and the shield case 11 are desirably about 0.4 mm, and the oblique cutout portion 13 is It is desirable that the chamfer dimension is about C0.6 mm.

Therefore, according to the first embodiment described above, by providing the oblique cutout portion 13 at the corner portion of the L-shaped land 12a, the oblique cutout portion 13 of the L-shaped land 12a and the corner portions 11f and 11g of the shield case 11 are formed. The distance L1 is an appropriate distance.
Therefore, the distance L1 and the height H of the fillet-shaped portion 22a are appropriate distances, a sufficient fillet-shaped portion 22a is formed, and the bonding strength of the corner portions 11f and 11g of the shield case 11 can be increased.

Next, a second embodiment of the present invention will be described based on FIG. 7 with reference to FIGS. The same parts as those in the first embodiment will be described with the same reference numerals (the same applies to the following embodiments).
In this embodiment, an R notch 24 notched in R is provided at the corner of the L-shaped land 12a, and the R-notched portion 24 of the L-shaped land 12a and the corners 11f and 11g of the shield case 11 are formed. The distance L1 and the distance L2 between the side portion of the L-shaped land 12a and the side portion of the shield case 11 are set to be approximately the same as an appropriate distance.

Therefore, according to the second embodiment described above, by providing the R notch 24 at the corner of the L-shaped land 12a, the R notch 24 of the L-shaped land 12a and the corners 11f and 11g of the shield case 11 are provided. L1 is an appropriate distance.
Therefore, the distance L1 and the height H of the fillet-shaped portion 22a are appropriate distances, a sufficient fillet-shaped portion 22a is formed, and the bonding strength of the corner portions 11f and 11g of the shield case 11 can be increased.

Next, a third embodiment of the present invention will be described with reference to FIG.
In this embodiment, a double R cutout portion 17 cut into a double R is provided at a corner portion of the L shape land 12a, and a double R cutout portion 17 of the L shape land 12a and a corner portion 11f of the shield case 11 are provided. The distance L1 to 11g and the distance L2 between the side portion of the L-shaped land 12a and the side portion of the shield case 11 are set to be approximately the same as an appropriate distance.
The center point of the R shape of the double R cutout portion 17 is preferably located at the corner portions 11f and 11g of the shield case 11, and the R radius is preferably about 0.4 mm.

Therefore, according to the third embodiment described above, by providing the double R notch 17 at the corner of the L-shaped land 12a, the double R notch 17 of the L-shaped land 12a and the corner 11f of the shield case 11 are provided. , 11g is an appropriate distance L1.
Therefore, the distance L1 and the height H of the fillet-shaped portion 22a are appropriate distances, a sufficient fillet-shaped portion 22a is formed, and the bonding strength of the corner portions 11f and 11g of the shield case 11 can be increased.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
In this embodiment, a reverse R notch 19 cut out in a reverse R is provided at the corner of the L-shaped land 12a, and the reverse R cut-out 19 of the L-shaped land 12a and the corner 11f of the shield case 11 are provided. The distance L1 to 11g and the distance L2 between the side portion of the L-shaped land 12a and the side portion of the shield case 11 are set to be approximately the same as an appropriate distance.

Therefore, according to the fourth embodiment described above, by providing the reverse R notch 19 at the corner of the L-shaped land 12a, the reverse R notch 19 of the L-shaped land 12a and the corner 11f of the shield case 11 are provided. , 11g is an appropriate distance L1.
Therefore, the distance L1 and the height H of the fillet-shaped portion 22a are appropriate distances, a sufficient fillet-shaped portion 22a is formed, and the bonding strength of the corner portions 11f and 11g of the shield case 11 can be increased.

  The present invention is not limited to the above-described embodiment, and can be applied to, for example, a non-foldable mobile phone or other various portable electronic devices.

It is an exploded view of the foldable mobile phone in the embodiment of the present invention. It is a perspective view which shows the principal part of the circuit board in embodiment of this invention. It is a disassembled perspective view which shows the relationship between the circuit board and shield case in embodiment of this invention. It is a perspective view which shows the circumference of the land part in embodiment of this invention. It is a top view of the shield case part in 1st embodiment of this invention. It is sectional drawing which follows the CC line of FIG. 5 in embodiment of this invention. It is a top view of the shield case part in 2nd embodiment of this invention. It is a top view of the shield case part in 3rd embodiment of this invention. It is a top view of the shield case part in 4th embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mobile phone, 10 ... IC package, 11 ... Shield case, 11a ... Planar part, 11b ... Side wall, 11c ... Side wall, 11d ... Hole, 11e ... Hole, 11f ... Corner | angular part, 11g ... Corner | angular part, 12 ... Land ( Reference potential pattern land), 12a... L-shaped land, 12b... I-shaped land, 13... Diagonal cutout (cutout), 17 ... Double R cutout (cutout), 20 ... Reverse R cutout ( Notch), 22 ... solder, 22a ... fillet-shaped part, 24 ... R notch (notch), 34 ... circuit board

Claims (3)

  A circuit board for soldering a polygonal shield case onto a polygonal reference potential pattern land, the outer shape of which is a polygon, and a cutout is provided at a corner of the reference potential pattern land. A circuit board characterized by that.   2. The circuit board according to claim 1, wherein an IC package constituting a wireless unit or a control unit is mounted on a circuit board in a reference potential pattern land having an outer shape of a polygon. A portable wireless device comprising the circuit board according to claim 1 or 2 in a housing.

Images