JP2007201356A - Mounting method of shield - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mounting method of a shield frame capable of improving the mounting efficiency of a printed circuit board, making it possible to visually confirm component loading position, when mounting the shield frame, and obtaining self alignment effect, even during rework without the need for adding special apparatuses, processes or increasing the cost. <P>SOLUTION: The printed circuit board 1 for soldering and loading a cylindrical or box-shaped shield 3 with no bottom comprises a base material and a solder pattern 5, provided in a frame-like pattern so as to match the lower end shape of the shield 3 on the base material. The solder pattern 5 has narrow width parts 4, narrower than the other parts locally at one or more sets of positions symmetric with respect to the pattern center, and the lower end position of the shield 3 is biased to one side of the widthwise direction of the solder pattern 5 at the narrow width parts 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to component mounting for portable terminals and the like, and more particularly to a shield mounting method.

  When a shield is mounted on a printed circuit board by reflow, the insulation material that constitutes the printed circuit board and the wiring pattern provided on the printed circuit board are expanded by heating, which is caused by the difference in the respective expansion coefficients and the weight of the printed circuit board Thus, the entire printed circuit board may be warped. Then, the level of the printed circuit board cannot be maintained, and the mounting position of the shield may be shifted.

  FIG. 6 is a schematic diagram showing a conventional shield mounting method. By providing through holes (positioning holes) 13 having a diameter of about 1 mm at two locations on the solder pattern 12 on the printed circuit board 11 as far as possible from each other, and mounting them through the misalignment prevention pins 15 provided on the side surfaces of the shield 14. Further, the mounting position shift of the shield 14 is prevented when the printed board 11 is inclined by heating in the reflow furnace.

  However, in this conventional shield mounting method, wiring cannot be provided over the entire layer of the printed circuit board 11 in the region of the positioning hole 13, which is an obstacle to forming a device having a large circuit scale. There is a problem. In addition, when the molten solder flows out to the back surface of the printed circuit board 11 through the positioning holes 13, there is a problem that a problem such as a circuit short circuit due to excess solder easily occurs on the back surface of the printed circuit board 11. Furthermore, there is a problem in that a solder ball may wrap around the back surface of the printed circuit board 11 through the positioning hole 13 to cause structural problems.

  In order to solve this problem, as disclosed in Patent Document 1, as shown in FIG. 7, an earth pattern land 18 for soldering a shield case frame member 17 to a printed circuit board 16 is provided with a shield case frame member. 17 is printed and formed so as to have a width wider than the frame width of 17, and the portion of the earth pattern land 18 that is in contact with the shield case frame member 17 when mounted is the same as or slightly the frame width of the shield case frame member 17. A solder resist 19 having a wide width is formed, and then cream solder is applied to the earth pattern land 18 and the electronic component placement land 21 for mounting the electronic component 20, and the electronic component 20 is mounted and soldered by reflow. After the attachment, the shield case frame member 17 is soldered onto the earth pattern land 18. Since the solder resist 19 exists, even after reflow for soldering the electronic component 20, solder does not flow up to the mounting position of the shield case frame member 17 of the earth pattern land 18, and the shield case frame member is placed on the earth pattern land 18. 17 can be in close contact and soldered.

  However, the technique of Patent Document 1 has a problem in that when the entire printed circuit board 16 is warped due to heat, the mounting position of the shield case frame member 17 may be displaced.

In addition, as a method for preventing a mounting position shift due to reflow, Patent Document 2 discloses a method for preventing a position shift when mounting the ground terminal 22 on the printed circuit board 23. As shown in FIG. 8, solder portions 24 and 25 are provided on the bottom portion 22a of the ground terminal 22 including the bottom plate 22a, the folded portion 22b, and the contact portion 22c, and the centers O ₁ and O ₂ of the solder portions 24 and 25 are provided. Through-holes 26 and 27 having a symmetric shape with respect to a perpendicular bisector Z of a line segment connecting the two are formed.

  Cream solders 30 and 31 are applied to the pads 28 and 29 provided on the printed circuit board 23 and placed in alignment with the through holes 26 and 27 formed in the bottom plate 22a of the ground terminal 22 by a component mounting machine or the like. The soldering parts 24 and 25 formed on the bottom plate 22a are joined to the pads 28 and 29 by heating the cream solders 30 and 31 by a reflow furnace or the like.

  If a part of the inner wall surface of the through-holes 26, 27 is displaced outward from the outer wall surface of the pads 28, 29 when the positional displacement occurs during bonding, the melted solder paste 30, 31 is formed on the displaced inner wall surface portion. The force resulting from the wraparound and the surface tension acts in a direction to eliminate the positional deviation with respect to the bottom plate 22a, and the positional deviation between the ground terminal 22 and the pads 28 and 29 is suppressed. By suppressing the displacement of the ground terminal 22 and the pads 28 and 29, solder fillets are formed on most of the inner wall surfaces of the through holes 26 and 27, and the soldering strength is improved.

Further, as shown in FIG. 8C, the direction of the straight line passing through the centers O ₁ and O ₂ of the soldering portions 24 and 25 is the U-axis direction, the vertical 2 of the line segment connecting the centers O ₁ and O ₂ , etc. When the direction of the dividing line Z is the V-axis direction, notches 32 to 40 are formed on the opposite outer sides of the bottom plate 22a in the U-axis direction, and formed on one outer side (the upper side in FIG. 8C). The cutouts 32, 33, 34, 35 and the cutouts 36, 37, 38, 39 formed on the other outer side (the lower side in FIG. 8C) are formed symmetrically with respect to the U axis. Yes.

Cutout portion of 32,33,36,37 (about 1/4 in the area) is located in four corners of the soldering section 24, notch 32, 36 and notches 33 and 37 of the center _{O 1} It is formed in a symmetrical shape with respect to a line parallel to the V-axis, and part of the notches 34, 35, 38, 39 (about ¼ in area) is located at the four corners of the soldering part 25, The notches 34 and 38 and the notches 35 and 39 are formed in a symmetrical shape with respect to a line passing through the center O ₂ and parallel to the V axis. For this reason, the soldering parts 24 and 25 are symmetrical with respect to the centers O ₁ and O ₂ (symmetric in the vertical and horizontal directions in FIG. 8C).

  With this configuration, when bonding occurs, for example, between the ground terminal 22 and the pads 28 and 29 in FIG. 9, the amount of molten cream solder that adheres to the notches 32 and 36 and the notches 33 and 37. Becomes unbalanced, and the amount of molten cream solder adhering to the notches 34 and 38 and the notches 35 and 39 becomes unbalanced, and the pads of the soldering portions 24 and 25 are caused by the force resulting from the surface tension of the molten cream solder. Misalignment with respect to 28 and 29 is suppressed. Further, since the solder fillet is formed across the notches 32 to 40 of the ground terminal 22 and the pads 28 and 29, the shape of the solder fillet becomes larger and the soldering strength is increased as compared with the case where the notches 32 to 40 are not provided. It is to increase.

  However, in this technique, since it is necessary to form a through-hole in the surface to be joined to the pad by solder cream, it is difficult to apply when the shield frame is mounted on the printed circuit board by reflow.

  Patent Documents 3 to 5 disclose a method for preventing a position shift when mounting a component on a substrate or the like by surface tension of a solder cream that has been liquefied by heating without forming a through hole on a joint surface.

  The technique disclosed in Patent Document 3 is a printed circuit board in which an electronic element mounting land such as a metal foil is formed on the surface of an insulating material, and a circumferential portion of a circular electronic element mounting land larger than the terminal of the electronic element When one or a plurality of indentations are formed in the electronic device and the electronic device is soldered to the circular electronic device mounting land by a reflow soldering method, the electronic device moves when the electronic device moves due to the surface tension of the solder. By forming one or a plurality of indentations in the circumferential portion of the mounting land, the mounting position accuracy after moving by the self-alignment function is better than when only the solder adhesion portion is formed by the solder resist. That's it.

  As shown in FIG. 9, when an electronic element having a circular terminal is soldered by a reflow soldering method, among the four recesses 41 in the circumferential portion formed on the circular electronic element mounting land 40, the diagonally diagonally located recesses 41 are diagonally arranged. By setting the shortest distance between the two indentations to be equal to or slightly shorter than the diameter of the terminal 42 of the electronic element, the terminal 42 of the electronic element was surrounded by the four indentations 41 by the surface tension of the solder. It moves to the center of the electronic element mounting land 40 at the center, that is, the center of the electronic element mounting land 40, and is fixed at that position.

  Patent Document 4 discloses the following technique. As shown in FIG. 10, a solder paste 45 is dispersed on each of the four corners of the pad portion 44 on the pad portion 44 provided on the circuit board 43 and applied to an appropriate thickness by screen printing. A total of four solder paste application portions 45a to 45d separated from each other at intervals are provided, and the connection ends 46a of the terminals 46 are overlapped over all of the solder paste application portions 45a to 45d.

  When the solder paste 45 is heated and melted, the solder paste application portions 45a and 45b and the solder paste application portions 45c and 45d are spaced apart from each other in the longitudinal direction of the terminal 46. Exhibits a self-alignment effect that shifts the connection end 46a in the short direction of the terminal 46 (the direction of the arrow N1). Further, the solder paste application portions 45a and 45d and the solder paste application portions 45b and 45c further exhibit a self-alignment effect of shifting in the longitudinal direction of the terminal 46 (arrow N2 direction). Therefore, the connection end 46a can be shifted to a position where there is no distortion or less distortion with respect to the arrangement of the solder paste application portions 45a to 45d, and the terminal 46 can be accurately arranged at a desired position. Therefore, it is not necessary to provide pins for positioning each terminal 46 on the printed circuit board 1.

  Further, in Patent Document 5, when a circuit board device is mounted on a motherboard, a circuit board device including a motherboard having electrode pads and a substrate having signal electrodes connected to the electrode pads of the motherboard is provided on the substrate. A technique is disclosed in which a positional deviation in the rotational direction of the substrate is corrected by utilizing the surface tension of the solder by connecting the ring-shaped connecting portion to an annular land provided on the mother board.

  As shown in FIG. 11A, on the mother board 47, an electrode pad 48, a first annular land 49, and a second annular land 50 provided on the inner peripheral side of the first annular land 49 are arranged concentrically. Has been. The first annular land 50 is formed with, for example, two notches 49A in the circumferential direction, and the second annular land 50 is similarly formed with, for example, two notches 50A. These notches 50A are arranged at different positions in the circumferential direction with respect to the respective notches 49A of the annular land 49 (for example, positions shifted by 90 ° from the notches 49A with respect to the circumferential direction).

  Further, as shown in FIG. 11B, the back surface of the substrate 52 of the package component 51 as a circuit board device is connected to the annular land using signal electrodes 53 and 54, circuit components (not shown), and solder. A first ring-shaped connecting portion 55 and a second ring-shaped connecting portion 56 provided on the inner peripheral side of the first ring-shaped connecting portion 55 are arranged. The first ring-shaped connection portion 55 and the second ring-shaped connection portion 56 are formed of a ring-shaped metal film having a center O and are arranged concentrically. Further, in the ring-shaped connection portion 55, notches 55A are formed at two locations in the circumferential direction, for example, as in the annular land 49, and at the ring-shaped connection portion 56, two notches 56A are formed, These notches 55A and 56A are arranged at different positions in the circumferential direction.

  When the substrate 52 is mounted on the mother board 47, the electrode pad 48 and the signal electrodes 54 and 55 are aligned by the annular lands 49 and 50 and the ring-shaped connection portions 55 and 56. Can be soldered to the annular lands 49 and 50 of the motherboard, and at the time of soldering, the ring-shaped connection portions 55 and 56 and the annular lands 49 and 50 The board 52 is displaced on the mother board 47 in the circumferential direction of the ring-shaped connection portions 55 and 56 (rotation direction with the center of the connection portion on the ring as the axis) on the mother board 47. Can be held in an easy-to-use state.

  As a result, when the substrate 52 is displaced in the rotational direction on the mother board 47, the annular land 49 is applied while applying a rotational moment to the substrate 52 by the surface tension of the solder melted between the signal electrodes 53 and 54 and the electrode pad 48. And the ring-shaped connecting portions 55 and 56 can displace the substrate 52 in the rotational direction. Therefore, even when the substrate 52 is displaced in the rotation direction, the signal electrodes 53 and 54 and the electrode pad 48 can be brought into contact with each other by a so-called self-alignment effect using the surface tension of the solder.

  Further, by forming notches in both the annular lands 49 and 50 and the ring-shaped connecting portions 55 and 56, it is possible to perform alignment by colliding the notches when mounting the substrate 52. Even when the surface tension of the solder applied between the signal electrodes 53 and 54 and the electrode pad 48 is small, the substrate 52 can be aligned with the motherboard 47 in the rotational direction.

  Further, a plurality of annular lands 49 and 50 and ring-shaped connecting portions 55 and 56 are formed concentrically so that a plurality of ring-shaped connecting portions can be soldered to the respective annular lands on the motherboard. Therefore, the contact area of the solder that contacts the ring-shaped connection portion can be increased as a whole, and when the solder melts, the surface tension of the solder applied to the substrate 52 side can be increased.

  With the above operation, the positional deviation in the rotation direction when the circuit board device is mounted on the mother board is corrected.

JP-A-7-240591 JP 2001-332326 A Japanese Patent Laid-Open No. 10-335795 Japanese Patent No. 3184929 JP 2004-165288 A

  However, the above-described prior art has the following problems. The technique disclosed in Patent Document 3 is a method for preventing misalignment of an electronic element having a large number of grid-like pin arrangements. When the electronic element is mounted, the electronic element mounting land 40 can be visually observed. However, there is a problem that a visual mark for alignment is necessary. In addition, after mounting the electronic element, the recess 41 becomes a component area, which makes it impossible to mount other components. Furthermore, there is a problem that it is necessary to form a depression in both the electronic element mounting land 40 and the solder resist.

  Moreover, in the technique disclosed in Patent Document 4, once the connection end of the terminal is soldered to the pad portion, if the soldering is shifted, the self-alignment effect can be obtained again when reworking. There is a problem that it is not possible.

  In the technique disclosed in Patent Document 5, it is necessary to provide an annular land on the mother board 47, and it is necessary to provide a ring-shaped connection portion on the substrate, and a surface layer pattern can be drawn on the ring-shaped connection portion. However, there is a problem that it becomes an obstacle when forming a device having a large circuit scale.

  The present invention has been made in view of such problems, and does not require the addition of special devices and processes, and does not require an increase in cost, improves the mounting efficiency of the printed circuit board, and the component mounting position when mounting the shield frame. An object of the present invention is to provide a mounting method of a shield frame that can be confirmed by visual observation and can obtain a self-alignment effect even during rework.

  A printed circuit board according to the present invention is a printed circuit board for soldering and mounting a cylindrical or bottomless box-shaped shield, and a frame on the substrate so as to be aligned with the lower end shape of the shield. A solder pattern provided in a pattern, and the solder pattern is locally narrower than other parts at one or more positions symmetrical to the pattern center. The lower end position of the shield is biased to one side in the width direction of the solder pattern at the narrow portion.

  According to the present invention, when the shield is placed on the solder pattern and the solder is reflowed, the entire printed circuit board is warped due to the expansion of the base material of the printed circuit board caused by heating and the weight of the printed circuit board. When the level of the printed circuit board is not maintained, a force is exerted on the shield on the molten solder so as to deviate from the placed position, but the surface generated by the molten solder in the narrow width portion. Since the force that moves inward or outward acts on the shield due to the tension, it is possible to prevent the shield from being displaced from the position where the shield is placed.

  It has a copper foil pattern formed in the same shape as the solder pattern on the base material, and the solder pattern can be provided on the substrate by coating on the copper foil pattern.

  In addition, the solder pattern has a width such that the steady portion is positioned at the lower end of the shield at the center in the width direction of the solder pattern, and the narrow width portion exceeds 1/2 of the width of the steady portion. It preferably has a width.

  For example, the lower end edge of the shield and the solder pattern form a rectangular frame shape, and the narrow portion is provided at a central position in the longitudinal direction of each of the four sides of the rectangle. The solder pattern may be configured such that a portion outside or inside the lower end of the shield in the width direction is notched.

  Alternatively, the lower edge of the shield and the solder pattern have a rectangular frame shape, and the narrow portion is provided at each of the four corners of the rectangle, and the solder pattern is formed at the narrow portion. It can also be configured such that a portion outside or inside the lower end of the shield in the width direction is cut out.

  A method for mounting a shield on a printed circuit board according to the present invention includes: placing the shield on the solder pattern of the printed circuit board so that a lower end thereof is positioned on the solder pattern; and The method includes a step of reflowing the solder pattern by heating and a step of solidifying the solder melted by the reflow.

  According to the present invention, a narrow width portion is provided in the pattern of the shield soldering portion on the printed circuit board, and the mounting position of the shield is prevented by utilizing the surface tension caused by the molten solder. There is no need to add and cost does not increase. In addition, since there is no need to provide positioning holes and misalignment prevention pins on the printed circuit board, the wiring rate of the printed circuit board can be greatly improved, and further, there are no portions where the narrow width portions are cut out, that is, there is no solder pattern. By using the area as the component mounting area, the mounting efficiency of the printed circuit board can be further improved. In addition, by eliminating the positioning holes, it is possible to fundamentally prevent the occurrence of defects due to the outflow of solder to the opposite surface of the printed board. In addition, the component placement position can be visually confirmed when the shield is mounted. Furthermore, a self-alignment effect can be obtained even during rework.

  Next, embodiments of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1A is a schematic view showing a shield mounting method according to the first embodiment of the present invention, and FIG. 1B is a schematic view of the same as seen from above. A copper foil pattern 2 is formed in a rectangular frame shape so as to be aligned with the lower end shape of the shield 3 at a position where the rectangular shield 3 on the printed circuit board 1 having the pattern wiring is soldered. The solder pattern 5 is formed by applying a solder cream so as to have a shape. The copper foil pattern 2 and the solder pattern 5 are provided with a narrow portion 4 whose width is locally narrower than other portions at the longitudinal center position of each of the four sides of the rectangle. The copper foil pattern 2 and the solder pattern 5 are notched at the outer side of the lower end of the shield 3 in the width direction, thereby forming a notch 4a.

  Further, a portion (steady portion) other than the narrow width portion 4 of the copper foil pattern 2 and the solder pattern 5 has such a width that the lower end of the shield 3 is positioned at the center in the width direction of the copper foil pattern 2 and the solder pattern 5. And the narrow width portion 4 has a width exceeding 1/2 of the width of the stationary portion.

  The shield 3 is placed on the copper foil pattern 2 and the solder pattern 5 on the printed circuit board 1 so that the lower end of the shield 3 is positioned on the copper foil pattern 2 and the solder pattern 5. The solder melted by the reflow is solidified. Thereby, the shield 3 is mounted on the printed circuit board 1.

  As the printed circuit board 1 having pattern wiring, a pattern is formed by etching a copper foil on an insulating material having a thickness of about 1 mm and in which a resin is infiltrated into a glass woven cloth, and this is laminated by about 6 to 10 layers. Those having the above structure are generally used. Moreover, the copper foil pattern 2 can be formed at the time of pattern wiring formation.

  As the shield 3, an aluminum sheet metal having a thickness of about 0.1 mm is bent and formed in a box shape, and the surface is subjected to a plating process in order to improve the solder affinity.

  LSI or other components are mounted inside the shield 3, and the shield 3 has a role of not leaking the electromagnetic noise of the internal LSI to the outside, and a role of preventing electromagnetic noise from the outside from entering the inside. . Further, structurally, it serves to prevent the LSI inside the shield 3 and the printed circuit board 1 from being broken or broken due to the bending of the printed circuit board 1 or the like. For this reason, the area of the solder joint portion of the shield 3 is required to be as wide as possible.

  FIG. 2 is a schematic diagram showing stepwise the shield mounting method according to the present embodiment in a cross section taken along a line AA in FIG. First, a solder cream 6 is applied on the copper foil pattern 2 on the printed circuit board 1 to form a solder pattern 5 having the same shape as the copper foil pattern 2. Thereafter, the shield 3 is placed on the copper foil pattern 2 and the solder pattern 5 by a machine or the like (step 1). At this time, it is visually confirmed that there is no large displacement, and when there is a large displacement such that the shield 3 protrudes from the copper foil pattern 2 and the solder pattern 5, the displacement is naturally corrected before entering the reflow furnace. This is because even in the present invention, such a large shift cannot be corrected during reflow.

  Next, the printed circuit board 1 on which the shield 3 is placed is placed in a high-temperature (about 250 to 300 ° C.) reflow furnace. The insulating material and the copper foil pattern 2 constituting the printed circuit board 1 are expanded by heating, and warpage may occur in the entire printed circuit board 1 due to the difference in the respective expansion coefficients and the weight of the printed circuit board 1. Then, the horizontality of the printed circuit board 1 cannot be maintained, so that the force that tends to shift from the position placed on the shield 3 on the melted and liquefied solder cream 6a is any of the dotted lines shown in FIG. Work in the direction of the arrow. At this time, since the narrow portion 4 is provided in the solder pattern 5, the four sides of the rectangular shield 3 are on the inner side (FIGS. 1B and 2) due to the surface tension generated by the liquid solder cream 6 a. Since a force to move in the direction of the solid line arrow in FIG. 2 acts, it is possible to prevent the shield 3 from being displaced from the position where it is placed (step 2).

  The printed board 1 is taken out of the reflow furnace and the melted solder is solidified to complete the mounting of the shield 3 (step 3). Through the above steps, the shield 3 is mounted at a desired position on the printed circuit board 1 without causing a positional shift. Further, by using the cutout portion 4a of the narrow width portion 4, that is, the region where no solder pattern exists, as the component mounting region, it is possible to improve the mounting efficiency of the substrate.

  The copper foil pattern 2 is not necessarily formed, and the solder pattern 5 can be directly formed on the printed board 1. Further, it is not always necessary to provide the narrow width portion 4 in the copper foil pattern 2, and the same positional shift prevention effect can be obtained even if the narrow width portion 4 is provided only in the solder pattern 5.

  Next, a second embodiment of the present invention will be described. FIG. 3 is a schematic view showing a shield mounting method according to the second embodiment of the present invention. 3, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted. In the first embodiment described above, the narrow width portion 4 that is locally narrower than the other portions is provided at the central position in the longitudinal direction of each of the four sides of the rectangular frame-shaped copper foil pattern 2 and solder pattern 5. In the narrow width portion 4, the copper foil pattern 2 and the solder pattern 5 are notched at the outer side of the lower end of the shield 3 in the width direction, thereby forming the notch portion 4a. In this embodiment, the copper foil pattern 2 and the solder pattern 5 in the narrow width portion 4 are notched at the inner side of the lower end of the shield 3 in the width direction, thereby forming a notch portion 4a. In other respects, it has the same structure except it.

  In the present embodiment, in step 2 described above, due to the surface tension generated by the liquid solder cream 6a, the force to move outward (in the direction of the arrow shown in FIG. 3) acts on the four sides of the shield 3. Therefore, it is possible to prevent the shield 3 from being displaced from the position where it is placed. Also in the present embodiment, the mounting efficiency of the board can be improved by using the cutout portion 4a of the narrow width portion 4, that is, the region where no solder pattern exists, as the component mounting region.

  Further, as in the first embodiment, the copper foil pattern 2 is not necessarily formed, and the solder pattern 5 can be directly formed on the printed circuit board 1. Further, it is not always necessary to provide the narrow width portion 4 in the copper foil pattern 2, and the same positional shift prevention effect can be obtained even if the narrow width portion 4 is provided only in the solder pattern 5.

  Next, a third embodiment of the present invention will be described. FIG. 4 is a schematic view showing a shield mounting method according to the third embodiment of the present invention. 4, the same components as those in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description thereof is omitted. In the first embodiment described above, the narrow width portion 4 that is locally narrower than the other portions is provided at the central position in the longitudinal direction of each of the four sides of the rectangular frame-shaped copper foil pattern 2 and solder pattern 5. In the narrow width portion 4, the copper foil pattern 2 and the solder pattern 5 are notched at the outer side of the lower end of the shield 3 in the width direction, thereby forming the notch portion 4a. In this embodiment, the narrow width portion 4 is provided at each of the four corners of the rectangle, and the copper foil pattern 2 and the solder pattern 5 are located outside the lower end of the shield 3 in the width direction. This is different in that a portion is cut out, thereby forming a cutout portion 4a, and the other portions have the same structure.

  In the present embodiment, in step 2 described above, due to the surface tension generated by the liquid solder cream 6a, forces that try to move inward (in the direction of the arrow shown in FIG. 4) act on the four corners of the shield 3. Therefore, it is possible to prevent the shield 3 from being displaced from the position where it is placed. Also in the present embodiment, the mounting efficiency of the board can be improved by using the cutout portion 4a of the narrow width portion 4, that is, the region where no solder pattern exists, as the component mounting region.

  Further, as in the first and second embodiments, the copper foil pattern 2 is not necessarily formed, and the solder pattern 5 can be directly formed on the printed circuit board 1. Further, it is not always necessary to provide the narrow width portion 4 in the copper foil pattern 2, and the same positional shift prevention effect can be obtained even if the narrow width portion 4 is provided only in the solder pattern 5.

  Next, a fourth embodiment of the present invention will be described. FIG. 5 is a schematic view showing a shield mounting method according to the fourth embodiment of the present invention. 5, the same components as those in FIGS. 1 to 5 are denoted by the same reference numerals, and detailed description thereof is omitted. In the third embodiment described above, the narrow frame portions 4 provided in the rectangular frame-shaped copper foil pattern 2 and the solder pattern 5 are provided in each of the four corners of the rectangle. The solder pattern 5 is notched at a portion outside the lower end of the shield 3 in the width direction, thereby forming a notch portion 4a. In the present embodiment, the narrow width portion 4 is made of copper. The foil pattern 2 and the solder pattern 5 are different in that a portion inside the lower end of the shield 3 in the width direction is cut out, thereby forming a cutout portion 4a, and the other portions have the same structure. ing.

  In the present embodiment, in step 2 described above, due to the surface tension generated by the liquid solder cream 6a, forces that move outward (in the direction of the arrow shown in FIG. 5) act on the four corners of the shield 3. Therefore, it is possible to prevent the shield 3 from being displaced from the position where it is placed. Also in the present embodiment, the mounting efficiency of the board can be improved by using the cutout portion 4a of the narrow width portion 4, that is, the region where no solder pattern exists, as the component mounting region.

  Further, as in the first to third embodiments, the copper foil pattern 2 is not necessarily formed, and the solder pattern 5 can be directly formed on the printed circuit board 1. Further, it is not always necessary to provide the narrow width portion 4 in the copper foil pattern 2, and the same positional shift prevention effect can be obtained even if the narrow width portion 4 is provided only in the solder pattern 5.

  In the first to fourth embodiments of the present invention, since the shield 3 has a rectangular shape, the copper foil pattern 2 and the solder pattern 5 have a rectangular frame shape. However, the shield 3 is not limited to a rectangular shape but has a cylindrical shape or the like. But you can. When the shield 3 has a cylindrical shape, the copper foil pattern 2 and the solder pattern 5 have a narrow width portion 4 at one or more positions symmetrical to the center of the ring-shaped pattern, and the narrow width portion 4 has a cylindrical shape. By providing the lower end position of the shield 3 so as to be biased to one of the copper foil pattern 2 and the solder pattern 5 in the width direction, the same effect as in the first to fourth embodiments can be obtained. When mounting on the printed circuit board 1, mounting can be performed without causing a positional shift from the mounted position.

(A) is a schematic diagram which shows the mounting method of the shield which concerns on 1st Embodiment of this invention, (b) is the schematic diagram similarly seen from the upper surface. FIG. 2 is a schematic diagram showing step by step a shield mounting method according to the first embodiment of the present invention in a cross section taken along a line AA in FIG. 1. It is a schematic diagram which shows the mounting method of the shield which concerns on 2nd Embodiment of this invention. It is a schematic diagram which shows the mounting method of the shield which concerns on 3rd Embodiment of this invention. It is a schematic diagram which shows the mounting method of the shield which concerns on 4th Embodiment of this invention. It is a schematic diagram which shows the mounting method of the conventional shield. It is a schematic diagram which shows the mounting method of the conventional shield case. This is a method for preventing the displacement of the mounting position during conventional soldering. This is a method for preventing the displacement of the mounting position during conventional soldering. This is a method for preventing the displacement of the mounting position during conventional soldering. This is a method for preventing the displacement of the mounting position during conventional soldering.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Printed circuit board 2; Copper foil pattern 3; Shield 4; Narrow part 4a; Notch part 5; Solder pattern 6, 6a; Solder cream 11; Printed circuit board 12; Solder cream pattern 13;
14; Shield 15; Misalignment prevention pin 16; Printed circuit board 17; Shield case frame member 18; Earth pattern land 19; Solder resist 20; Electronic component 21; Electronic component placement land 22; Earth terminal 22a; 22c; contact part 23; printed circuit board 24, 25; soldering part 26, 27; through hole 28, 29; pad 30, 31; cream solder 32, 33, 34, 35, 36, 37, 38, 39;

Claims (8)

In a printed circuit board for soldering and mounting a cylindrical or bottomless box-shaped shield, a base material and a solder pattern provided on the base material in a frame-shaped pattern so as to be aligned with the bottom shape of the shield And the solder pattern has a narrow width portion that is locally narrower than other portions at one or more sets of positions that are symmetrical with respect to the pattern center, and the narrow width portion. In the printed circuit board, the lower end position of the shield is biased to one side in the width direction of the solder pattern. The printed circuit board according to claim 1, further comprising a copper foil pattern formed in the same shape as the solder pattern on the base material, wherein the solder pattern is applied on the copper foil pattern. . The solder pattern has such a width that the steady portion is positioned at the lower end of the shield at the center in the width direction of the solder pattern, and the narrow portion has a width that exceeds 1/2 of the width of the steady portion. The printed circuit board according to claim 1, wherein the printed circuit board has a printed circuit board. The lower end edge of the shield and the solder pattern form a rectangular frame shape, and the narrow portion is provided at a central position in the longitudinal direction of each of the four sides of the rectangle. The printed circuit board according to any one of claims 1 to 3, wherein a portion of the pattern is cut out at a portion outside the lower end of the shield in the width direction. The lower end edge of the shield and the solder pattern form a rectangular frame shape, and the narrow portion is provided at a central position in the longitudinal direction of each of the four sides of the rectangle. 4. The printed circuit board according to claim 1, wherein the pattern is cut out at a portion inside the lower end of the shield in the width direction. 5. The lower end edge of the shield and the solder pattern have a rectangular frame shape, and the narrow portion is provided at each of the four corners of the rectangle, and the solder pattern has a width at the narrow portion. 4. The printed circuit board according to claim 1, wherein a portion outside the lower end of the shield in a direction is cut out. 5. The lower end edge of the shield and the solder pattern have a rectangular frame shape, and the narrow portion is provided at each of the four corners of the rectangle, and the solder pattern has a width at the narrow portion. The printed circuit board according to any one of claims 1 to 3, wherein a portion inside the lower end of the shield in a direction is cut away. A step of placing the shield on the solder pattern of the printed circuit board according to any one of claims 1 to 7 so that a lower end thereof is positioned on the solder pattern, and heating the printed circuit board And a step of reflowing the solder pattern, and a step of solidifying the solder melted by the reflow.

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