PACKAGING OF ELECTRICAL COMPONENTS

Abstract: A container for loosely housing dual-in-line components 4 comprises an elongate tubular member 1. The tubular member is substantially U-shaped in cross-section and inclu­ des a hollow central portion 2 for receiving the body of the components, and flanking portions 3 for receiving the legs 5 of the components. The tubular member is so shaped that the components can only touch the tubular member in certain predetermined locations 8, 9, 10, and to protect the com­ ponents from static discharges on contacting the container, only these locations need be made conductive, the remainder of the container being of transparent plastic. In one embodiment the container may be provided with conducting ribs (13) on the outside so that when two such containers come into contact it is not possible for two non-conducting parts to come into contact so generating static.

Description: This invention relates to the packaging of electrical components, particularly of the type having terminals in a so-called "dual-in-line" configuration, that is two laterally spaced rows of terminals protruding in substantially the same direction so that the component is substantially U-shaped in transverse cross-section, the rows of terminals forming the legs of the U and the body of the component forming the central portion thereof. Such an electrical component is that hereinafter referred to as being "of the kind described". Some components of this kind, for example metal-oxide semi-conductor (MOS) integrated circuits, are highly susceptible to static electrical charges and must be packed in anti-static or conducting containers so as to prevent the application of a static charge to one of the terminals of the component which could cause an internal electrical breakdown. It is known from GB 1593760 to provide such a container in the form of a tubular member of uniform closed inverted U-shaped cross section formed of plastics material, said cross section consisting of a base wall portion adapted to support the bodies of a row of said components therein, a flanking portion on each side of the said base portion adapted to receive respective rows of said terminals, and a top portion adapted to overlie said component bodies and joining the respective flanking portions, said base and flanking portions being electrically conductive and said top portion being transparent. This container is generally effective in protecting components packed therein, but it is relatively expensive since it is made mostly of conducting material, excepting only the transparent top. GB-A-2081226 discloses a container for housing components of the kind described in the container that has a transparent upper half for inspection, and a conductive lower half for receiving the terminals. However, components can still be damaged if the tube is inverted in use, and inspection of the rows of terminals is difficult. Accordingly the present invention is characterised in that said tubular member comprises a plurality of spaced electrically conductive portions which are contactable by a said component when housed therein, the remainder of the the tubular member being non-contactable by a said component when housed therein and being substantially transparent, said conductive portions being electrically interconnected. Clearly such an arrangement substantially minimises the amount of electrically conductive material in the container, thus substantially reducing its cost and at the same time substantially maximising its transparency. In a preferred form of the invention the said electrical conductivity is provided substantially in only three portions of the said container extending lengthwise thereof, the conductive portions comprising the base wall of the said hollow central portion so as to underlie the said body of the or each component, and two opposed inwardly projecting portions of the container arranged to extend along the opposite sides of the said component(s) and to engage the latter upon upward or lateral displacement thereof, whereby to prevent the component(s) from coming into contact with any non-conductive portions of the container. As stated above, the said conductive portions are substantially the only parts of the said tubular member which are contactable by the or each component, but means are also provided to electrically interconnect the aforementioned conducting portions, so as to provide for uniform conductivity and thereby avoid differences in voltages which might cause short-circuiting of the components. Preferably the electrical interconnections are provided at one or both ends of the container, however it will be appreciated that there are other possible arrangements. While an electrical connection at each end of the tube is preferred, it is possible to provide only a single connection at any point along the tube. Indeed connections between different adjacent pairs of conductive portions could be provided at different positions. The container may be formed from suitable plastics material, preferably PVC. The electrically conductive portions thereof may be formed in any suitable manner, but it is preferred to form them by incorporating carbon particles in the material forming the container. The transparent parts of the container may be made antistatic if desired, while still remaining substantially transparent, for example by providing them with a transparent anti-static coating. Additionally the container may be provided with a plurality of upstanding conducting ribs on the external surface of the tubular member, arranged so that when two such containers are juxtaposed side by side it is not possible for any non-conductive portions of the containers to contact each other. This reduces the amount of static that is generated in a stack of such containers since the contact between two containers is either between two conductive portions or a conductive and a non-conductive portion. Preferably these ribs are provided on all the outwardly projecting corners of the tubular member. Preferably a pair of end plugs are provided, formed of plastics material, which seal the ends of the tubular member. Some embodiments of the invention will now be described by way of example and with reference to the accompanying drawings in which:- Figure 1 is a transverse cross-sectional view of a first embodiment of a container according to the invention, containing an electrical component of the kind described; Figure 2 is a view similar to Figure 1 showing a second embodiment; Figure 3 is a perspective view of the container of Fig. 1; Figure 4 is a cross-sectional view of the containers of Figures 1 and 2 in use, Figure 5 is a view of modified forms of the embodiments of Figures 1 and 2; and Figure 6 is a view of a stack of the containers of Fig 5(a). Referring first to Figures 1 and 3, there is shown a container 1 having a closed substantially U-shaped transverse cross-section. This cross-section includes a hollow central portion 2, and a hollow flanking portion 3 on each side of the central portion. These hollow portions are arranged so that, in use, the body portion 4 of an electrical component of the kind described is held within the central portion 2 and its rows of terminals 5 are received within the respective flanking portions 3. The width of the central portion 2 is only slightly greater than the width of the body portion of an electrical component to be housed in the container. In addition two opposed shoulders 6 are provided in the outside walls of the tubular member 1 at the junctions between the central portion and the flanking portions. The shape of each such shoulder corresponds approximately to the shape of the terminals 5 where they join the body portion 4 of the electrical component. As a consequence the possible movement of the electrical component is restricted and the component can only contact the tubular member 1 in three regions, namely in the vicinity of the shoulders 6 and the portion 7 of the tubular member defining the base wall or floor of the central hollow portion 2. This latter part of the tubular member underlies and supports the body 4 of an electrical component housed within the tubular member. Thus, in order to protect an electrical component from a static discharge when it contacts the tubular member, it is only necessary that the aforementioned regions of possible contact should be electrically conductive. These possible places of contact are shown in the drawings as the darkly shaded parts. Thus the tubular member has three strips 8, 9 and 10 of conductive material extending along its length, which are formed by incorporating carbon particles in the plastics material. The embodiment of Figure 2 is substantially the same as that of Figure 1 save that it is much wider in order to accommodate a wider electrical component. The tubular member is also be provided with additional electrically conductive portions 12 (Fig. 3) at one or both ends which electrically interconnect the three longitudinally extending strips 8, 9 and 10. In the absence of such a provision it would be possible for two of the conductive strips to be at different potentials, and if an electrical component were to contact such two strips simultaneously a potential difference would be applied across the component and it could be damaged. The tubular member is formed from a plastics material such as PVC and is generally transparent except for the electrically conductive portions thereof. There may also be provided two end plugs (not shown) made of a suitable plastics material and each having a projecting portion shaped to fit within an end of the tubular member and a rim which abuts the end of the tubular member. It would of course be possible for the aforementioned means electrically interconnecting the said conductive portions to be provided on one or both of the end plugs. As is shown in Fig. 4 the cross-sectional shape of the tubular member is such that an electrical component of the kind described can only contact the walls of the tubular member at three regions, which are rendered conductive by the addition of conducting material. This enables the amount of conducting material needed to be greatly reduced, and accordingly it is possible to manufacture the tubular member out of predominantly transparent material allowing the observation of components contained within the tubular member. Figs. 4(a) 4(c) show a component held within the container of Fig. 1 while Figs. 4(b) and 4(d) show a component held within the container of Fig. 2. As can be seen from Fig. 4 no matter how the component moves it only touches the base portion and the opposed shoulders of the tubular member. One of the major causes of static charge being present on such containers is friction occuring between the non-conducting portions of two such containers when they rub against each other. It is therefore desirable to prevent the non-conducting portions of one container from contacting the non-conducting portions of another when they are juxtaposed side by side. Figs. 5(a) and 5(b) show modified forms of the embodiments of Figs 1 and 2 respectively, which meet this requirement. In these modified containers bulbous ribs of electrically conductive material extend longitudinally along the outwardly directed corners 13 of the shoulder portion and the upper part of the central portion, and the outwardly directed corners 14 at the base of the flanking portions. As shown in Fig 5 these conductive ribs extend a distance α above the principal surfaces of the container. The effect of these ribs is to prevent the non-conducting portions of two containers from contacting one another when the containers are stacked. This effect is shown in Fig. 6, which shows a stack of such containers, where it will be seen that all contacts between adjacent containers are either between conductive material and conductive material, or between conductive material and non-conductive material.

Claims: A container for loosely housing at least one electrical component having a body portion (4) and two rows of terminals (5) extending from opposed sides of said body portion (4), said container comprising an elongate tubular member (1) of closed substantially inverted U-shaped transverse cross-section, said cross-section including a hollow central portion (2) for receiving the said body portion (4) of the or each said component, and two hollow flanking portions (3) one on each side of said central portion (2) for receiving the said rows of terminals (5), the container being partly of electrically conductive material and partly of transparent material, characterised in that said tubular member (1) comprises a plurality of spaced electrically conductive portions (8,9,10) which are contactable by a said component when housed therein, the remainder of the the tubular member (1) being non-contactable by a said component when housed therein and being substantially transparent, said conductive portions (8,9,10) being electrically interconnected. A container according to claim 1 wherein said conductive portions (8,9,10) extend lengthwise of the container and comprise the base wall (8) of said hollow central portion (2) so as to underlie the said body portion (4) of the or each component, and two opposed inwardly projecting portions (9,10) of the container arranged to extend along the opposite sides of the said component(s) and to engage the latter upon upward or lateral displacement thereof. A container according to claim 1 or 2, wherein said conductive portions (8,9,10) are made conductive by carbon particles incorporated in the material of the container. A container according to any preceding claim, further comprising a pair of end plugs for sealing the ends of said container. A container according to any preceding claim, wherein said conductive portions (8,9,10) are electrically interconnected at at least one end of the container. A container according to any preceding claim, wherein the said tubular member (1) is provided with upstanding conducting ribs (13,14) on the external surface thereof, arranged so that when two such containers are juxtaposed side by side the non-conductive portions of the containers cannot contact each other. A container according to claim 6, wherein said conducting ribs (13,14) extend lengthwise of the container along the outwardly projecting corners of said tubular member (1) A package comprising a container as claimed in any preceding claim which loosely houses one or more electrical components having a body portion (4) and two rows of terminals (5) extending from opposed sides of said body portion (4).

Inventors: YEN WEI HSIUNG
Applicants: YEN WEI HSIUNG
Application year: 1986
Main classification: H05K13
IPC codes: B65D81, H05K13