Methods of manufacture of electrical components

Abstract

 A method of manufacturing an antenna or inductive component comprises producing (eg by injection moulding) a former (10) of an electrically insulating material which has a groove (12) in its surface. A layer (14) of electrically conducting material is deposited over the surface of the former and this layer is then removed from the surfce of the former excepting the groove. Hence, the former is left with an electrically conducting element extending along the base of the groove.

Description

Field of the Invention

[0001] This invention relates to a method of manufacturing electrical components, especially antenna components and inductors, and to electrical components manufactured by said method.

Background to the Invention

[0002] The manufacture of electrical components such as inductances and antenna coils is conventionally achieved by winding a wire into a helical form, either around a generally cylindrical former or without a former if the mechanical properties of the wire are such that it is shape-retaining and self-supporting in the wound condition.

[0003] In mass production, especially for low inductance values or intended high frequency operation in the case of antenna components, the inevitable mechanical tolerances which are realistically achievable make it difficult to control the component parameters and values.

[0004] It is a primary aim of this invention to provide an improved method of manufacturing electrical components (such as inductance and antenna components) more readily, enabling accurate control of component parameters and values.

The Invention

[0005] According to the present invention, in its broadest aspect, a method of manufacturing an electrical component comprises the steps of producing a former of electrically insulating material which has a pattern of one or more grooves in its surface, depositing a layer of electrically conductive material over the surface of the former, including at least the bottom of the or each groove, and removing the conductive layer from the surface of the former excepting the groove or grooves.

[0006] Where the surface of the former is referred to herein, the surface in question may be the exterior surface of a solid former, or either the external or the interior surface of a hollow former, such as a tubular former.

[0007] Also according to the present invention, in another aspect, a method of manufacturing an antenna or inductive component comprises the steps of producing a former of electrically insulating material which has a helical or pseudo-helical groove in its surface, and providing a layer of electrically conductive material in the groove but not the remainder of the surface of the former.

[0008] Preferably, although not essentially, in the production of an antenna or inductive component, the entire surface of the former is provided with a covering layer of conductive material, and the conductive layer is removed except at the helical or pseudo-helical groove.

[0009] The present invention thus enables components to be repeatedly produced which are mechanically stable and have precisely controlled parameters and values.

[0010] Moreover, whereas in the prior art it is usual for inductances and antenna components to be helically wound, for example on a cylindrical former, the present invention makes it readily possible if desired to produce such components with a non-circular cross-section, such as polygonal cross-section.

[0011] It is also to be appreciated that, in the case of radio frequency components, it is possible for the conductive layer to be relatively thin because, as radio frequencies travel on the surface of conductors, thin components are in use able to perform equally as well as thicker and more solid components.

[0012] The former used in the present invention may be produced in any one of a number of different ways, eg machining, but injection moulding of plastics material is especially suitable. As heretofore mentioned, the former may be a hollow such as tubular body, with the conductive layer on its interior surface.

[0013] Likewise, various methods can be employed to deposit the conductive layer, but electroplating may be preferred. Plating techniques for plastics and other non-metallic materials are well known. Other possible methods of producing the conductive layer are:-

(a) application as a foil or laminate, either as a required shape, eg a helix, or over the whole interior and/or exterior surface of the former, with subsequent shaping as required

(b) application in the form of a metallised paint or ink, either in a required shape or over the entire former surface with subsequent shaping.

[0014] When, for example, a plating technique is employed, the entire surface of the former, including the walls as well as the bottom of the grooves, will have an applied conductive layer. It may thus be desired for the grooves moulded or otherwise produced in the surface of the former to be of V-shaped cross-section, but a rectangular U-shaped cross-section is preferred.

[0015] Thus in a preferred method for the manufacture of an antenna component or inductance, the former is moulded of plastics material with a helical (or pseudo-helical) V- or U-groove in its surface, which may be the exterior or interior surface in the case of a tubular or hollow former. The term "pseudo-helical" is used because it is not essential for the former to be of circular cross-section.

[0016] The deposited conductive layer on the main surface of the former can be removed in a variety of ways, more particularly mechanical methods such as machining or abrading.

Description of the Embodiment

[0017] The method in accordance with the invention is exemplified in the following description, making reference to the accompanying drawings, in which:-

Figure 1 shows a cylindrical former having a helical V-groove in its surface;

Figure 2 illustrates the step of removal of a plated conductive layer from the main surface of the former;

Figure 3 shows a tubular former having a rectangular U-groove on its interior surface, conductively coated;

Figure 4 shows in side view a former which could be used for manufacture of other electrical components such as a filter component; and

Figure 5 shows the finished filter component.

[0018] Referring first to Figures 1 and 2, in a preferred method of manufacture of inductance and antenna components, first a cylindrical former 10 is injection moulded of an insulating plastics material. The former is moulded with a groove 12 extending helically along its length.

[0019] Second, a layer 14 of a suitable metal - such as copper - is plated over the entire surface of the former, including the groove 12, as indicated at 16.

[0020] Third, the conductive layer 14 is removed from the main portion of the surface of the former, as indicated at 18. The conductive layer 14, 16 then remains only in the V-groove and constitutes a helical inductance or antenna element of electrically conducting material.

[0021] In Figure 3 is shown a tubular former 10A having a rectangular U-shaped groove 12A extending helically along the length of its interior surface. A layer of conductive material 14A is applied over the entire surface, as by plating for example, and this layer is then removed from the helical peak between the groove, ie, where indicated at 18A.

[0022] In the case of the tubular, cylindrical component shown in Figure 3, this will then be incorporated in an antenna unit having a metal rod, sometimes known as a whip, sliding through the finished former and capacitatively or inductively or mechanically coupled to the conductive helix. The metal rod is not shown in Figure 3 but it can readily be visualised as a cylindrical rod extending through the component of Figure 3 and making sliding contact with the ungrooved areas 18A.

[0023] Referring to Figure 4, a plastics moulded former 20 is shown which could be employed in the manufacture of an electrical filter component. This example is given only by way of explanation, as in practice the illustrated former would be more readily and cheaply produced by machining than by moulding. However, the figure is illustrative of the fact that complex formers can readily be plastics moulded, to constitute the basis of various electrical components carrying a plated electrical element or an array of plated electrical elements.

[0024] Figure 5 shows the finished filter component in the instance of this simple example, wherein after metal plating the conductive deposition has been removed from the main surface 22 of the former, leaving the conductive elements 24 in the rectangularly cross-sectioned grooves 26. It will be appreciated that electrically conducting paths of complex shape can be produced by moulding a former of the appropriate shape with the necessary grooves, depositing a metal layer on the former and then removing the metal layer except in the grooves.

Claims

1. A method of manufacturing an electrical component, comprising the steps of producing a former of electrically insulating material which has a pattern of one or more grooves in its surface, depositing a layer of electrically conductive material over the surface of the former, including at least the bottom of the or each groove, and removing the conductive layer from the surface of the former excepting the groove or grooves.

2. A method of manufacturing an antenna or inductive component, comprising the steps of producing a former of electrically insulating material which has a helical or pseudo-helical groove in its surface, and providing a layer of electrically conductive material in the groove but not the remainder of the surface of the former.

3. A method according to claim 2, wherein the entire surface of the former is provided with a covering layer of conductive material, and the conductive layer is removed except at the helical or pseudo-helical groove.

4. A method according to any of the preceding claims, wherein the former is produced by injection moulding of plastics material.

5. A method according to any of the preceding claims, wherein the former is a hollow Dody with the groove in its interior surface.

6. A method according to any of the preceding claims, wherein the conductive layer is deposited by electroplating.

7. A method according to any of claims 1 to 5, wherein the conductive layer is deposited by application as a foil or laminate, either as a required shape, eg a helix, or over the whole interior and/or exterior surface of the former, with subsequent shaping as required.

8. A method according to any of claims 1 to 5, wherein the conductive layer is deposited by application in the form of a metallised paint or ink, either in a required shape or over the entire former surface with subsequent shaping.

9. A method according to any of the preceding claims, wherein the grooves are of V-shaped cross-section, or rectangular U-shaped in cross-section.

10. An electrical component made by a method according to any of the present claims.

Drawing