EP1121845A1

EP1121845A1 - Screen that prevents the penetration of electromagnetic radiation

Info

Publication number: EP1121845A1
Application number: EP00967525A
Authority: EP
Inventors: Jochen Steininger
Original assignee: DeTeWe Deutsche Telephonwerke AG and Co KG; Deutsche Telephonwerke und Kabelindustrie AG
Current assignee: DeTeWe Deutsche Telephonwerke AG and Co KG; Deutsche Telephonwerke und Kabelindustrie AG
Priority date: 1999-08-13
Filing date: 2000-08-08
Publication date: 2001-08-08
Also published as: WO2001013694A1; DE29914661U1

Abstract

The invention relates to a screen that prevents the penetration of electromagnetic radiation towards or from electric or electronic circuit elements of an electric circuit that are arranged on a substrate. The inventive screen consists of a metal housing that comprises a frame (2) configured by lateral walls (21 to 24) and inner walls (41, 42) that are located within the frame (2) and that define at least one chamber. Said inner walls together with the lateral walls (21 to 24) are punched from one piece of metal. The screen further comprises a lid that can be linked with the lateral walls (21 to 24) and/or the inner walls (41, 42). The lateral walls (21 to 24) and the inner walls (41, 42) consist of perpendicular lateral wall sides (211 to 242) and inner wall sides (411 to 422). Respective side portions, namely the narrow lateral wall sides (212, 222, 232, 242) and the narrow inner wall sides (412, 422) are linked with the substrate and their width is adapted to the width of the soldered tracks that are located on the substrate.

Description

Shielding to prevent the passage of electromagnetic radiation

description

The invention relates to a shield for preventing the passage of electromagnetic radiation according to the preamble of claim 1.

From DE 296 02 025 Ul a shield for electrical or electronic circuit elements of an electrical circuit for radio telephones arranged on a printed circuit board is known, which consists of a two-part shield housing with a side wall part and a cover which is press-fitted onto the side wall part. The side wall part has inner partition walls that extend between the side walls and form additional shielding chambers within the shield. The side wall part and the inner partition walls are punched out of a flat sheet metal, with slots or recesses being arranged in the corner regions, so that when the side wall and the inner partition walls are bent over, a perpendicular is formed protruding frame with inner chambers is formed from the circuit board. Due to the formation of dome-shaped curves in the corner regions of the side wall, feet of the shield are provided, which are used as soldering points for soldering the side wall part to a ground plane of the substrate.

However, the formation of soldering support points at the corner points of the side wall part includes the risk that a gap remains between the lower edges of the side wall part and the surface of the printed circuit board through which electromagnetic radiation can pass. However, an additional solder path drawn along the lower edges of the side wall part causes an increased effort when soldering and unsoldering the side wall part. Furthermore, the chambers formed by the inner partition walls are not optimally connected to the circuit board or the housing cover, so that the chambers are not optimally secured against the passage of electromagnetic radiation to the circuit components arranged in the remaining area of the shield.

From DE 81 23 367.1 U1 a two-part shielding housing for a high-frequency component is known, which likewise consists of a metallic frame and a cover which can be press-fitted onto the metallic frame. The two-part shielding housing surrounds a high-frequency component which has solder pins on its underside, which can be inserted through openings in the metal housing and connected to the circuit board. The object of the present invention is to provide a shield of the type mentioned at the outset, the frame of which can be connected to the substrate in a simple manner, the passage of electromagnetic radiation to or from the electrical or electronic circuit elements arranged on the substrate also in the connection region of the frame to the Effectively prevents substrate, a block against the passage of electromagnetic radiation from the chamber or chambers formed within the frame also at the connection to the lid, a mechanically safe and radiation-proof connection between the lid and frame is ensured and is simple and inexpensive to manufacture.

This object is achieved by the features of claim 1.

The solution according to the invention connects the frame of a shielding housing in a simple manner with the substrate receiving the electrical sheath and effectively prevents the passage of electromagnetic radiation to or from the electrical or electronic circuit elements of the circuit arranged on the substrate, also in the connection region of the frame with the substrate. In addition, the passage of electromagnetic radiation from a chamber formed within the frame is also blocked at the connection to the cover and a mechanically safe and radiation-proof connection between the cover and the frame is ensured. Furthermore, the high-frequency shielding housing according to the invention is simple and inexpensive to manufacture. An advantageous embodiment of the solution according to the invention is characterized in that the side walls and the inner walls are bent in an L-shape and are composed of wide side wall legs and narrow side wall legs forming the side walls and wide inner wall legs and narrow inner wall legs forming the inner walls, and that the narrow side wall legs and the narrow inner wall legs are connected to the substrate. The width of the narrow side wall and inner wall legs is matched in particular to the width of a solder path arranged on the substrate.

Preferably, at least a portion of the corners of the side walls and / or the inner walls relative to the substrate and to be arranged in bores of the substrate are provided positioning pins with which the frame can be fixed at predetermined positions on the substrate. This ensures an exact assignment of the frame and thus the shielding housing to the circuit arranged on the substrate, as well as easy assembly and fastening of the frame on the substrate.

A further development of the solution according to the invention is characterized in that the cover has a flat cover surface resting on the upper edges of the side walls and inner walls, from the edges of which resilient lugs are bent at right angles, which can be brought into mechanical and electrical contact with the side walls. To optimize the positive and non-positive connection of the connection between the frame and the cover of the shielding housing, that of the cover surface opposite ends of the resilient lugs on a kink, which can be locked with a bead in the side walls of the frame.

If necessary, the cover surface can be provided with heat removal openings and a closed partial surface which can be brought into contact with a suction gripper of a lifting and placing device. Alternatively, a special device for placing the lid on the frame or for lifting the lid off the frame can be used without opening or closing the shielding housing being associated with damage to the lid or frame.

An advantageous embodiment of the solution according to the invention is characterized in that the inner walls have tongues directed away from the substrate and that slots are provided in the cover surface for receiving the tongues. This constructive design ensures that the chamber is secured against the penetration of electromagnetic radiation into or out of the part of the electrical circuit surrounded by the frame.

The idea on which the invention is based will be explained in more detail with reference to an exemplary embodiment shown in the drawing. Show it:

Fig. 1 - a schematic perspective view of the underside of the shield according to the invention;

Fig. 2 - a plan view of the shield according to

Figure 1; 3 shows a bottom view of the shield according to FIG. 1;

Fig. 4 - a side view of the shield according to

Figure 1;

5 to 7 - details of the connection between

Cover and frame of a shield according to Figures 1 to 4;

8 and 9 - a perspective view from below and above on the frame of the shield;

Fig. 10 - a plan view of the frame according to the

Figures 8 and 9;

11 and 12 - side views of the frame according to FIG. 10;

Fig. 13 - an enlarged view of the area

XIII according to Figure 11;

Fig. 14 - a section through the frame along the

Line XIV-XIV according to Figure 10;

Fig. 15 - an enlarged view of the area

XV according to Figure 14;

16 shows a schematic illustration of a stamped sheet metal part for producing a frame according to FIGS. 1 to 15. 17 is a perspective view of the cover of the shield;

Fig. 18 - a plan view of the lid according to

Figure 17;

Fig. 19 - a side view of the lid according to the

Figures 17 and 18;

Fig. 20 - an enlarged view of the area

XX according to Figure 19;

21 and 22 - an enlarged view in plan view and in a section through the area XXI according to Figure 18 and

The shield shown in FIGS. 1 to 7 in different views and individual part enlargements for preventing the passage of electromagnetic radiation to or from electrical or electronic circuit elements of an electrical circuit arranged on a substrate consists of a two-part metallic housing 1, preferably a two-part sheet metal housing, with a the substrate can be placed on and connected to this frame 2, onto which a cover 3 can be placed in a force-fitting and / or form-fitting manner. FIG. 1 shows a schematic perspective view of the two-part metallic housing 1 from the underside with the cover 3 placed on the frame 2. The rectangular frame 2 consists of four side walls 21 to 24 and a chamber 4 arranged within the frame 2 formed by the side walls 21 to 24 with inner walls 41, 42 which adjoin the side walls 21 and 24 of the frame 2, so that two side walls of the Chamber 4 are formed by the corresponding portions of the side walls 21 and 24. This chamber 4 serves for additional shielding to prevent the passage of electromagnetic radiation to or from the electrical or electronic circuit elements arranged within the chamber 4 to or from the electrical or electronic components of the electrical circuit arranged within the frame 2 but outside the chamber 4.

At predetermined locations on the lower edges of the side walls 21 to 24, in the illustrated embodiment at diagonally opposite corners of two meeting side walls 21 to 24, positioning pins 5 are arranged, which can be inserted into prefabricated openings in the substrate for positioning and fixing the position of the metallic housing 1 on the substrate ,

As can be seen in particular from the individual representations of the frame 2 in FIGS. 8 to 15 described below and the enlarged individual part representation of the connection of the inner walls 41, 42 to the cover 3 according to FIG. 6, the side walls 21 to 24 and inner walls 41, 42 are rectangular mutually standing side wall legs 211 to 242 and inner wall legs 411 to 422 are assembled. Preferably, and shown in the embodiment, the side wall and inner wall legs are L-shaped and each consist of one long legs forming the actual side wall and inner wall and a short leg forming the support of the frame on the substrate, the short legs 212, 222, 232, 242 and 412, 422 being connected to the substrate, for example by a soldered connection.

The cover 3 consists of a flat cover surface 30, within which holes 31 are provided at regular or irregular intervals for dissipating the heat given off by the electrical or electronic components or the heat generated during the soldering process. A closed partial surface 36 can optionally be provided on the cover surface 30, which can be brought into contact with a suction pad of a lifting and placing device, for example.

On the cover surface 30 of the cover 3, indentations 33 are also provided in the region of the upper edges of the inner walls 41, 42 of the chamber 4, towards the interior of the two-part housing 1, slots 32 being provided at their lowest points. As can be seen in particular from the enlarged individual part representation according to FIG. 6, the slots 32 serve to receive tongues 43 arranged on the upper edge of the inner walls 41, 42 of the chamber 4 are angled, the tongues 43 of the inner walls 41, 42 are inserted into the slots 32 when the lid 3 is placed on the frame 2 and thus ensure easy assembly and exact positioning of the tongues 43 within the slots 32 of the lid surface 30. The outer edges of the lid surface 30 of the lid 3 are bent at right angles and are designed as resilient lugs 35 which rest on the outer surfaces of the side walls 21 to 24 of the frame 2. For optimal fixing of the cover 3 on the frame 2, the side walls 21 to 24 of the frame 2 have beads 25 (FIGS. 5 and 7) running in the longitudinal direction of the side walls 21 to 24 and the resilient lugs 35 of the cover 3 have a kink 37 at their ends which engages over the beads 25 when the cover 3 is completely placed on the frame 2 and thus locks the cover 3 with the frame 2 and thus ensures complete mechanical and electrical contact between the frame 2 and the cover 3.

Figure 6 shows in an enlarged detail a section through the inner wall 41, which consists of a wide, vertical inner wall leg 411 and a narrow inner wall leg 412 bent at right angles from the wide, vertical inner wall leg 411, which rests on the surface of the substrate or by means of a solder connection to the Surface of the substrate is connected. For the corresponding connection of the side wall and inner wall legs resting on the surface of the substrate, solder tracks are provided on the substrate, which are connected to the inner wall and side wall legs by heating or by an additional soldering process.

FIGS. 8 to 15 show different views and individual parts of the frame 2 after the frame 2 has been bent from the stamped part shown in FIG. 16. The perspective views looking towards the underside (FIG. 8) and top side (FIG. 9) of the frame 2 show the frame 2 composed of the side walls 21 to 24 with the chamber 4 composed of the inner walls 41 and 42 and parts of the side walls 21 and 24 within the frame 2. The side walls 21 to 24 and inner walls 41, 42 have an L-shaped profile in which the wide side wall legs 211, 221, 231, 241 form the actual side walls 21 to 24, while the narrow side wall legs 212, 222 , 232, 242 serve as a support for the substrate or a solder path provided on the substrate.

In the same way, the inner walls 41, 42 are composed of wide inner wall legs 411, 421 and narrow inner wall legs 412, 422, of which the narrow inner wall legs 412, 422 rest on soldering tracks on the substrate and are connected to it. At the upper ends of the wide inner wall legs 411, 421 of the inner walls 41, 42 tongues 43 are provided at regular intervals, which engage in the corresponding slots 32 in the cover 3 according to FIGS. 1 to 7.

FIG. 10 shows a top view of the frame 2, the composition of the side walls 21 to 24 and inner walls 41, 42 with the respective side wall and inner wall legs 211 to 242 or 411 to 422.

The side views of the long sides and transverse sides illustrated in FIGS. 11 and 12 illustrate the beads 25 arranged in the wide, vertical side wall legs and the height of the side walls 21 to 24 protruding tongues 43 on the upper edges of the inner walls 41, 42. Furthermore, the side views show the vertically downwardly projecting position pins 5, which are arranged at diagonally opposite corners of the frame 2. Of course, other position pins can also be formed, for example, at the corners of the chamber 4.

FIG. 13 shows an enlarged partial view of area XIII according to FIG. 11 and illustrates the arrangement and assignment of the tongues 43, the positioning pins 5 and the beads 25 on the side walls 21 to 24 of the frame 2.

FIG. 14 shows a cross section through the frame 2 along the line XIV-XIV according to FIG. 10 and FIG. 15 shows an enlarged representation, in particular of the area of the inner wall 41 of the chamber 4 corresponding to the encircled part XV according to FIG. 14. This representation shows an enlarged view of a side wall 41 of the chamber 4 with the tongues 43 arranged on its upper edge, which project beyond the side walls 21 to 24 of the frame 2 in height and are shaped such that they have a decreasing thickness and width towards their upper edge. This facilitates the insertion of the tongues 43 into the slots 32 of the cover 3 for a positive and positive and electrically conductive connection to the cover surface 30 of the cover 3. Furthermore, FIG. 15 shows a section through the side wall 21 with the bead 25 formed therein and one Position pin protruding vertically downwards from the frame 5. The production of the frame 2 from a chromed or galvanized sheet metal part will be explained in more detail in connection with the illustration in FIG. 16.

FIG. 16 shows a basic illustration of a punched-out sheet metal part for producing a frame 2 according to FIGS. 1 to 15 without details such as free cuts or incisions. In the punched-out state, the wide and narrow side wall legs 211, 212, 221, 222, 231, 232, 241, 242 of the side walls 21 to 24 and the wide and narrow inner wall legs 411, 412, 421, 422 of the inner walls 41, 42 lie in one plane in front. By making cuts in the corners of the adjoining side walls 21 to 24 and inner walls 41, 42 and, if appropriate, by embossing lines 6 which mark the bending lines for bending the wide side wall legs 211, 221, 231, 241 and wide inner wall legs 411, 421, the bending process is prepared to produce the shield.

To connect the frame 2 to the substrate, the narrow side wall legs 212, 222, 232, 242 and narrow inner wall legs 412, 422, which extend parallel to the surface of the substrate, lie on the surface or on suitably prepared solder tracks on the surface of the substrate.

In addition, impressions 25 are provided in the side walls 21 to 24, which serve the beads for receiving the resilient lugs 35 of the cover 3. Furthermore, the punched-out sheet metal part has, in particular, tapering position pins 5 on diagonally opposite corners of the side walls 21 to 24 of the frame 2, which are opposite to the Bending direction of the wide side wall legs 211, 221, 231, 241 and the wide inner wall legs 411, 421 are bent so that they can be inserted into corresponding holes on the substrate.

FIGS. 17 to 22 show the cover 3 in different views and enlarged individual parts. The cover 3 is punched out of a sheet metal part analogously to the frame 2 and then bent into the shape shown in FIGS. 17 to 22.

FIG. 17 shows a perspective view of the cover with the cover surface 30, in which numerous heat dissipation openings 31 are arranged. A closed partial surface 36 of the cover surface 30 can, if required, be brought into contact with a suction pad, a lifting and placing device. As an alternative to this, a special gripper for mounting or removing the cover can engage on the cover edges or on diagonally opposite corner points of the cover 3 in order to place the cover 3 on the frame 2 or remove it from the frame 2 of the HF shielding.

In the cover surface 30 indentations 33 in the form of tongues directed towards the inside of the cover 3 are further provided, which form the lateral boundary of the slots 32 which receive the tongues 43 on the inner walls 41, 42 of the chamber 4 in the assembled state of the two-part housing.

The details described above can be seen from the top view of the cover 3 according to FIG. 18 and the side view according to FIG. 19, which in particular show the design of the resilient lugs 35 which are bent off from the edges of the cover surface 30 of the cover 3. The resilient lugs 35 are arranged distributed over the length of the side walls of the cover 3 and, compared to their length, enclose short gaps between them.

FIG. 20 shows, in an enlarged partial representation, the area XX according to FIG. 18 to clarify the structural shape of the resilient lugs 35. These have a kink 37 at their ends, which in the assembled state of the cover 3 on the frame 2 over the kink 25 of the frame 2 takes hold.

FIG. 21 shows a top view and FIG. 22 shows a section of area XXI according to FIG. 18 on an enlarged scale. This enlarged illustration clarifies the design of the indentations and slots in the area of the chamber 4 for receiving the tongues 43 of the inner walls 41, 42 of the frame 2.

The indentations are designed as tongues 33, which for

Are directed inside the lid 3 and are bent at their ends to the outside of the lid 3 and one

Limit slot 32 in which the tongues 43 of the inner walls

41, 42 can be inserted.

* * * * *

Claims

Expectations

Shielding for preventing the passage of electromagnetic radiation to or from electrical or electronic circuit elements of an electrical circuit arranged on a substrate with an metallic housing, which has a frame formed from side walls, arranged inside the frame, at least one chamber forming inner walls, which together with the side walls are stamped out of a metal part and have a cover which can be connected to the side walls and / or the inner walls,

characterized,

that the side walls (21 to 24) and inner walls (41, 42) consist of mutually perpendicular side wall legs (211 to 242) and inner wall legs (411 to 422), each of which a leg part (212, 222, 232, 242; 412, 422 ) is connected to the substrate.

Shielding according to Claim 1, characterized in that the side walls (21 to 24) and the inner walls (41, 42) are bent in an L-shape and from wide side wall legs (211, 221, forming the side walls (21 to 24),

231, 241) and narrow side wall legs (212, 222,

232, 242) and wide inner wall legs (411, 421) forming the inner walls (41, 42) and narrow inner wall legs (412, 422) are assembled, and that the narrow side wall legs (212, 222, 232, 242) and the narrow inner wall legs (412, 422) are connected to the substrate.

Shielding according to Claim 1 or 2, characterized in that the substrate has solder tracks over at least part of the length of the side walls (21 to 24) and inner walls (41, 42) and in that the width of the narrow side wall legs (212, 222, 232, 242 ) and the narrow inner wall legs (412, 422) are matched to the width of the solder tracks arranged on the substrate.

Shielding according to at least one of the preceding claims, characterized in that at least part of the corners of the side walls (21 to 24) and / or the inner walls (41, 42) are bent towards the substrate and position pins (5) to be arranged in holes in the substrate are provided with which the frame (2) can be fixed at predetermined positions on the substrate.

Shielding according to at least one of the preceding claims, characterized in that the cover (3) has a flat cover surface (30) resting on the upper edges of the side walls (21 to 24) and inner walls (41, 42), from the edges of which resilient lugs ( 35) are bent at right angles, which can be brought into mechanical and electrical contact with the side walls (21 to 24). Shielding according to Claim 5, characterized in that the ends of the resilient lugs (35) opposite the cover surface (30) have a kink (37) which is provided with a bead (25) in the side walls (21 to 24) of the frame (2) can be locked.

Shielding according to at least one of the preceding claims, characterized in that the cover surface (30) has heat removal openings (31) and a closed partial surface (36) which can be brought into contact with a suction pad of a lifting and placing device.

Shielding according to at least one of the preceding claims, characterized in that the inner walls (41, 42) have tongues (43) directed away from the substrate and that slots (32) are provided in the cover surface (30) for receiving the tongues (43).

Shielding according to claim 8, characterized in that the slots (32) are arranged in indentations (33) of the cover surface (30) directed towards the substrate.

10. Shielding according to claim 9, characterized in that the indentations consist of the slots (32) delimiting tongues (33) which without a gap from the cover surface (30) cut free and bent at their ends (34) forming the slot (32) to the outer surface of the lid.

11. Shielding according to at least one of the preceding claims 8 to 10, characterized in that the tongues (43) project beyond the side walls (21 to 24) of the frame (2) in height.

12. Shielding according to at least one of the previous ones

Claims, characterized in that the slots

(32) are shaped such that the tongues (43) are non-positive and / or positive and electrically conductive with the

Cover surface (30) can be connected.

13. Shielding according to at least one of the preceding claims, characterized in that the tongues (43) have a decreasing thickness or width towards their upper edge.

* * * * *