GB2188773A

GB2188773A - Housing for a hybrid circuit

Info

Publication number: GB2188773A
Application number: GB08618777A
Authority: GB
Inventors: Elmar Sieben
Original assignee: ROSE ELEKTROTECH GmbH; Rose Elektrotechnik GmbH and Co KG
Current assignee: ROSE ELEKTROTECH GmbH; Rose Systemtechnik GmbH
Priority date: 1985-08-02
Filing date: 1986-07-31
Publication date: 1987-10-07
Also published as: FR2585881B1; FR2585881A1; GB2188773B; DE3527818A1; GB8618777D0; DE3527818C2

Abstract

The invention provides a housing for a hybrid circuit carrier (21), equipped on both sides with components (22), consisting of a deep-drawn housing cover (4) and a deep-drawn housing floor (1), which can be hermetically connected at the edges, the housing floor (1) having an edge area (13) with an attaching and bearing surface (13A) for the hybrid circuit carrier (21) and in relation to which the inner area (14) is lowered by slightly more than the height (H) of the components contact pins (12) with insulating bushings (11) being arranged in rows passing through the edge (13) are at right angles to the bearing surface (13A). <IMAGE>

Description

SPECIFICATION Housing for a hybrid circuit The invention relates to a metal housing, for a hybrid circuit, comprising a housing floor with rows of contact pins passing perpendicularly and in insulated manner through an edge area thereof, and a complementary deep-drawn housing cover which can be hermetically sealed.

There are known housings for hybrid circuits which have a flat floor so that a hybrid circuit to be attached thereto, with components attached to it, can only be equipped with components on its side facing the housing cover, the hybrid circuit consisting of a circuit carrier comprising a printed circuit board, a thin- or thick-film substrate.

It is further known to mount hybrid circuits equipped on both sides at a distance from the housing floor, the heat transfer from the circuit carrier to the housing being thereby reduced however, and the side and the height tolerances between the contact points on the circuit carrier and the contact pins to be connected therewith being increased, a fact which complicates the connection technique, especially a bonding technique, i.e. a connection technique with thin spot-welded wires. For this type of arrangement of hybrid circuits, housings are also known whose floors are deep-drawn and in which the contact pins are inserted in the deep-drawn floor area, and whose edge area stands upright and perpendicular thereto outside the pin rows.

It is the object of the present invention to provide a housing for a hybrid circuit which is easy to produce, and in which can be arranged a circuit carrier which is equipped on both sides, and which has improved heat transfer to the housing and diminished tolerances between the contact points on the circuit and the corresponding contact pins.

This object is achieved in that according to the present invention the housing floor is lowered by deep-drawing by a little more than the height of a component only in an inner area which lies between the edge area through which the contact pins pass.

A further advantage of the construction of the invention is that the form of the lowered floor area increases the bending resistance of the housing floor in comparison with a flat floor of uniform thickness. Thus, it is advantageously possible to decrease the thickness and hence the weight of the housing floor considerably in relation to known housings, a fact which is especially significant for use in aeronautical devices because of the weight saving.

Also, for a device constructed of several hybrid circuits, because the mounted hybrid circuit carriers are equipped on both sides, altogether a reduction in the number of housings is obtained and the space needed for their accommodation on circuit carriers can be considerably reduced, which inter alia saves on production costs, material, space and weight.

Furthermore, there is also the advantage that the contact pins are accessible from the sides for the purpose of testing, if the housing is incorporated in a circuit board. Because the edge area, in which the contact pins are located, lies raised above a circuit board by the depth of the lowered part of the housing floor, the risk of solder shorts over the contact bushings is practically ruled out. The raised circumferential edge zone also provides improved heat transfer to the currounding air.

The production of cylindrical contact pins is relatively easy, as no compression, bending or the like are necessary.

Advantageous embodiments of the housing are described hereinafter with reference to Figs. 1 to 4 of the accompanying drawings, wherein: Figure 1 is a section taken on the line I-I of Fig. 2 through a hybrid circuit incorporated with a housing into a circuit board, an exploded view before the housing is closed being given on an enlarged scale in area B; Figure 2 is a plan view of a portion of a housing floor according to Fig. 1; Figure 3 is a section of a portion of a housing floor with a double row of contacts; Figure 4 is a section of a portion of a housing floor of thinner material with a bonded circuit portion.

Fig. 1 shows, in area A, a hybrid circuit 2 assembled and inserted into a circuit board 5 and consisting of a circuit carrier 21 with components 22 arranged on both sides and comprising bores 23 at the edges, through which bores pass contact pins 12 which are inserted with insulating bushings in the housing floor 1. The housing floor comprises a deep-drawn inner area 14 which serves to receive the components 22 on one of the sides of the circuit carrier equipped therewith. The edge area 13 of the floor 1 provides, around each of the contact pins 12, an exact reference and mounting surface 13A for the circuit carrier 21.

The depth of the recess in the floor is somewhat greater than the height H of the components 22. The contact pin 12 projects through the reference surface 13A by only a tight tolerance which corresponds to the thick- ness S of the circuit carrier 21 or is a little larger, so as both to facilitate the insertion into the housing of the circuit carrier 21 with its tightly toleranced bores 23 and make possible the production of a bond connection 30 between the end faces 12S of the contact pins and a contact point 24 on the circuit carrier.

The insulating bushing 11 is so formed in a known way that during sintering of the glass melt there arises a flush or concave meniscus adjacent the bearing surface 13A, such that the circuit carrier 21 rests totally flat thereon and has good thermal contact with the housing floor. An adhesive serves to fix and produce reliable thermal contact. Instead of the bond connection 30 the contact pins can be connected by soldering a through-hole connection in the circuit carrier with the contact pins; because of their high reliability, however, adhesion and bonding are preferred.

As can easily be seen from the exploded representation in area B, the edge area 13 of the housing floor is provided, by stamping, with a stepped edge 15 running around the outside thereof and having a sealing projection 15D, which edge 15 receives, seals and connects with the projecting edge areas 45 of the housing cover 4.

The process of stamping the edge 15 and the deep-drawing of the inner area 14 are preferably effected in one operation and with one tool, so that tight tolerances are ensured and no additional production costs are brought about by the deep-drawing. The edge 15 and the edge area 45 are hermetically sealed together in a known manner after insertion of the hybrid circuit.

Fig. 2 is a plan view of a portion of housing floor 1 according to Fig. 1, in which a row of contact pins 12 is arranged on each of two opposite sides. All-round or multi-row contact pin arrangements can be arranged appropriately by one skilled in the art.

Fig. 3 shows a portion of a double-row arrangement, in cross-section. The bearing surface 13B in the edge area of the housing floor has passing through it the two adjacent staggered rows of pins 12A,12B.

Fig. 4 shows a further portion of a housing floor of deep-drawing sheet with a relatively small thickness D. The bending resistance of the housing floor is provided by the deepdrawn area 14 and deformation of the edge 15A. Furthermore, the bending resistance of the mounting of the contact pins 12C in the floor is provided in that around each bore 17 there is formed a stamped piece 16 which receives the insulating bushing 11A. The deep-drawing, deforming and stamping are carried out in one tool in one operation, so that tight tolerances are achieved.

The circuit carrier 2A is brought only as far as the contact pins 12C to simplify production and is adhered to the bearing surface 13C and connected with a bond connection 30A to the contact pin. However, in this way heat transfer is reduced in comparison with the circuit carrier arrangement of Fig. 1 providing wider support on the mounting surface.

Claims

1. A metal housing, for a hybrid circuit, comprising a housing floor with rows of contact pins passing perpendicularly and in insulated manner through an edge area thereof, and a complementary deep-drawn housing cover which can be hermetically sealed, characterised in that the housing floor is lowered by deep-drawing, by somewhat more than the height of a component, only in an inner area which lies between said edge area through which the contact pins pass.

2. A housing according to claim 1, wherein said edge area has a flat bearing surface which surrounds the contact pins, and wherein the contact pins are each held in an insulating bushing, preferably of sintered glass, which does not project beyond the bearing surface.

3. A housing, according to claim 2, wherein the contact pins project beyond the bearing surface by the thickness of a hybrid circuit carrier, or a slightly larger extent of tight tolerance, and their end faces are plane and parallel with the bearing surface.

4. A housing, according to claim 1, wherein the edge area is surrounded by a stepped edge lowered below the bearing surface and having a sealing projection.

5. A housing, according to any one of the preceding claims, wherein, in the edge area outwardly from the bearing surface, there are provided stampings in which the insulated bushings are inserted.

6. A housing, according to claim 5, wherein the stepped edge is angled and lowered to below the bearing surface.

7. A housing, according to any one of the preceding claims, wherein the circuit carrier is attached to the bearing surface, preferably by means of an adhesive.

8. A housing, according to claim 7, wherein the circuit carrier carries, arranged adjacent to each of the contact pins, contact points which are each connected by bond connectors to the appropriate end faces of the contact pins.

9. A housing substantially as described herein with reference to the figures of the accompanying drawings.