EP0569917A1

EP0569917A1 - Filter connector

Info

Publication number: EP0569917A1
Application number: EP93107591A
Authority: EP
Inventors: Tokita Hiroshi; Itoh Tsukasa
Original assignee: Whitaker LLC
Current assignee: Whitaker LLC
Priority date: 1992-05-11
Filing date: 1993-05-10
Publication date: 1993-11-18
Also published as: JPH0590859U; JP2592561Y2

Abstract

A filter connector comprises a magnetic plate member (11) having holes (12) and openings (13) extending therethrough, electrical contacts (20) are positioned in the holes (12) and capacitors (30) are positioned in the openings (13), electrodes (32, 33) of the capacitors (30) are electrically connected respectively to grounding conductive layer (15) and conductive patterns (17) on surfaces (14, 16) of the plate member (11) so that the contacts (20) are electrically connected to respective capacitors (30).

Description

This invention relates to filter-connectors, especially to filter-connectors designed to eliminate undesirable noise components from the signals carried by the contacts.
Highly sensitive electronic elements of audio and communication equipment and widely used digital equipment comprising digital IC's and other elements operating on ON-OFF principle are very susceptible to noises generated inside this equipment or penetrating therethrough via power supply lines or otherwise. Car audio equipment is especially strongly affected due to engine ignition and sparking from electric motors, etc. Therefore, it is necessary to use connectors with integral filters which reduce penetration and noise propagation through the electric system. It is also necessary to use filter connectors to reduce the interference between various electronic pieces of equipment and computers in offices and laboratories. FCC regulations concerning allowable levels of noise are becoming stricter, making it difficult to use electronic equipment without special arrangements for noise suppression.
Various types of filter-connectors have been proposed and are currently in use. As an example of a conventional filter-connector, reference is made to Japanese Utility Model No. 59-4549. In this conventional filter-connector, chip-type capacitors are connected onto a printed circuit board having openings for post-type contacts inserted through the openings with some plates of the capacitors being connected to the contacts and the other plates being connected to a common ground. Another type includes through-capacitors mounted by soldering to a conducting plate, contacts are inserted through the capacitors and secured by soldering after which the entire assembly is fixed by an insulating material.
Filter-connectors with a high density of contacts can be made by forming a thick-film layer on an insulating board thus making capacitors and connecting them to each contact (See, for example, U.S. Patent Nos. 4,682,129 and 4,791,391).
However, since in these conventional filter-connectors, filter elements are represented by capacitors only, their characteristics are not satisfactory; in addition, since the capacitors used for this purpose are thick-film or chip-type, both of which take much space, it is difficult to construct high-density filter-connectors. Another disadvantage is the necessity to perform the soldering of capacitors and contacts, which leads to a high production cost. The process of arranging or manufacturing chip or thick-film capacitors on the surface of the substrate is associated with considerable difficulties, while additional operations may result in damage to the already finished elements. It is also difficult to determine if all capacitors are of good quality.
The purpose of this invention is to offer low-cost production filter-connectors which can be made relatively small at a high density of contacts and which are strong and simple in handling.
A filter connector according to this invention comprises a plate member having holes therethrough in which electrical contacts are disposed and capacitors are electrically connected via conductive patterns on the plate to respective contacts and to a ground conductive layer, the plate member has openings in which the capacitors are positioned with electrodes of the capacitors electrically connected to the conductive patterns and the ground conductive layer.
In filter-connectors according to preferred embodiments of this invention a magnetic base plate made of ferrite or other magnetic material is used. In this magnetic base plate a number of openings is made for post-type contacts and for capacitors. A grounding conductive layer is formed on one side of the magnetic base plate, and conductive patterns connecting openings for capacitors and openings for contacts are made on the other side. Post-type contacts are inserted in the openings for contacts, and tubular or cylindrical capacitors are inserted in the openings for capacitors. One electrode of these tubular capacitors is soldered to the above mentioned grounding conductor, and the other one to the conductive pattern on the other side of the base plate connecting it to the contact. Thus, an inverse L-shaped filter is formed at each post contact consisting of inductance formed by the magnetic base plate, and of capacitance formed by the tubular capacitor.
In a preferred embodiment of the invention, each contact of the filter-connector has an inductance connected in series and the capacitance connected in parallel. Therefore, noise components carried by the contacts are effectively suppressed in a wide band of frequencies. Noise components flowing to the circuit through the contact are suppressed by the inductance and the components passing through the contact are deviated to the ground via the capacitance. Therefore, the filter-connectors according to this embodiment of the invention are to a greater degree more effective in noise suppression than conventional filter-connectors having only capacitors. In addition, since the tubular capacitors are fully inside the magnetic base plate, their electrodes are on the same level as the surfaces of the base plate, thus making it easy to carry out soldering operations and reducing the risk of damage during subsequent work.
The invention will now be described by way of example with reference to the accompanying drawings in which:

Figure 1 is a perspective view of the preferred embodiment of the filter-connector according to this invention for explanation purposes.
Figure 2 is a cross-sectional view of the assembled filter-connector shown in Figure 1.
Figure 3 is a cross-sectional view of an assembled connector in which the filter-connector shown in Figure 1 is mounted therein and on a circuit board.
Figure 4 is a view similar to Figure 3 showing an alternative embodiment.

Figure 1 is a perspective view showing the main elements of the filter-connector 10 according to this invention. In the specific embodiment shown in Figure 1, a 3 mm thick base plate 11 made of ferrite or other magnetic material is used. In this magnetic base plate 11, two rows of contact openings 12 extend therethrough; inside these two rows are two rows of openings 13 for capacitors corresponding to the contact openings 12. As it will be explained below with reference to Figure 2, a grounding conducting layer 15 is applied to almost the entire surface of one main surface 14 of the magnetic base plate 11; on the other main surface 16, the conductive patterns 17 connecting contact openings 12 with capacitor openings 13 are formed.
Post-type contacts 20 (in the specific design shown in Figure 1, thirty contacts are present) are pressed into the contact openings 12 of the magnetic base plate 11 from the side of surface 16 toward surface 14, and they are fixed in the openings. These post-type contacts 20 may have the connection portion 21 of a nearly square cross-section and the contact portion 22 establishing the connection with the mating contacts. The connection portions 21 protrude from the contact openings 12 over the surface 14 of the magnetic base plate 11 and may be, for example, connected by soldering to the throughholes of a circuit board (not shown in the drawing). These connection portions 21 may be bent perpendicular to the surface 14 of the magnetic base plate 11 to form an angled connector. In Figure 1, a part of contacts 20a is shown in the state when they are pressed in the magnetic base plate 11, while the remaining contacts 20b are shown in the state prior to their insertion. Contacts 20a that are pressed in the magnetic base plate 11 are soldered to the conductive patterns 17 formed on the main surface 16. The same is true regarding tubular capacitors 30.
Tubular capacitors 30 are inserted into the openings 13 provided for the capacitors of the magnetic base plate 11. Tubular capacitors 30 may be of the surface mounted type (MELF) obtained from Taiyo Yuden Co., Ltd. These capacitors are of the tubular type, they have electrodes at both ends, their length is 3 mm, and have 0.2 mm thick electrodes 32, 33 at both ends. The tubular capacitors need not be necessarily of a round cross-section, but they may be of a square or other cross-section. In the specific embodiment shown in Figure 1, they are round. Thus, when tubular capacitors 30 are inserted into the capacitor openings 13 made in the magnetic base plate 11, their bodies completely fit inside the openings 13 of the magnetic base plate 11, and the electrodes 32, 33 slightly protrude from the surfaces 14 and 16. The electrodes 32, 33 of the tubular capacitors 30 are soldered respectively to the conducting patterns 17 and to the conducting grounding layer 15.
Figure 2 represents a cross-section of the filter-connector 10 shown in Figure 1. It shows contacts 20 inserted into openings 12 and tubular capacitors 30 inserted into openings 13 made respectively for the contacts and capacitors in the magnetic base plate 11. As one can discern from the right side of Figure 2, the bodies 31 of all tubular capacitors 30 are completely fitted inside the capacitor openings 13 of the magnetic base plate 11, and only their electrodes 32, 33 are exposed at the main surfaces 16, 14 of the magnetic base plate 11. Therefore, these electrodes of the capacitors 30 can be easily soldered to the conductive grounding layer 15 and the conductive patterns 17. Such a configuration prevents tubular capacitors 30 from possible damage during subsequent manufacturing operations performed on the filter-connectors 10, or during their use when, for example, contacts 20 of the filter-connector 10 are inserted into contacts of another connector.
Figure 3 represents a cross-section of the filter-connector according to this invention shown in Figure 1 as part of an assembled connector mounted on a circuit board. A filter-connector 50 shown in Figure 3 is an example of a right-angle connector in which the filter-connector 10 is placed in an insulating housing 51. The filter-connector 10 may be, for example, inserted in the insulating housing 51 through an opening 52 to a shoulder 53, after which it can be secured from the back by means of the grounding member 54 having spring-lock elements on both sides. Grounding terminal 55 of this grounding member 54, and contacting portions 21 of all the contacts 20 bent at right angle are inserted into the contact through holes 61 and grounding through-holes 62 of the printed circuit board 60 and soldered thereto. After that, the filter-connector may be either soldered by its grounding conducting layer 15 or attached to the circuit board by an adhesive.
The assembly of the filter-connector 50' shown in Figure 4 differs from the assembly of the filter-connector 50 shown in Figure 3 by the fact that in Figure 4 the filter-connector 10 is placed on the grounding layer 63 of the circuit board 60, and may be secured thereto by soldering.
It is obvious that the filter-connector 10 according to this invention can be assembled in another different assembly configuration; for example, it may be placed and mounted on the circuit board 60 vertically.
In a magnetic base plate 11 made of ferrite or other magnetic material, openings 12 for contacts and openings 13 for capacitors exiting at the main surfaces 14 and 16 of the base plate are formed. Contacts 20 are pressed into the contact openings 12, and tubular capacitors 30 with electrodes 32, 33 are inserted in the capacitor openings 13. One electrode of the capacitors 30 is connected to the common conductive grounding layer 15 formed on the surface 14 of the magnetic base plate, and the other electrode is connected to contacts 20 by means of conducting patterns 17 formed on the main surface 16. The length of tubular capacitors 30 is selected to be practically equal to the thickness of the magnetic base plate 11, and therefore electrodes 32, 33 of the tubular capacitors 30 are substantially flush with the surfaces 14, 16 of the magnetic base plate 11.
The detailed explanations given above concern the preferred embodiment and examples of the application of the filter-connector according to this invention. However, this invention is not limited to these embodiments only, depending on the requirements; it may be modified in different ways which can be easily implemented by anyone having common knowledge in this field. For example, the openings for the capacitors may be made in two rows outside the openings for the contacts. The filter-connectors according to this invention may be also mounted directly on the circuit boards without housings.
In the filter-connectors according to this invention, the thickness of the magnetic base plate plays an important role in obtaining the desirable filter characteristics. Commonly available tubular capacitors are inserted in the openings provided for this purpose in the magnetic base plate for an efficient assembly. Therefore, since the filter-capacitors do not protrude from the surface of the magnetic base plate, they can be easily soldered, and additional handling of the filter-connectors does not present any danger of damaging them.
The purpose of the present invention is to provide a filter-connector characterized by excellent filtering properties which is easy in assembly, resistant to damage, small in size and has a high density of contacts per unit area.

Claims

A filter connector comprises a plate member (11) having holes (12) therethrough in which electrical contacts (20) are disposed and capacitors (30) are electrically connected via conductive patterns (17) on the plate (11) to respective contacts (20) and to a ground conductive layer (15), the plate member has openings (13) in which the capacitors (30) are positioned with electrodes (32, 33) of the capacitors electrically connected to the conductive patterns (17) and the ground conductive layer (15).
A filter connector as claimed in claim 1, characterized in that said openings (13) are positioned in said plate member adjacent respective holes (12).
A filter connector as claimed in claim 1 or 2, characterized in that said plate member is magnetic material.
A filter connector as claimed in claims 1,2 or 3, characterized in that the length of the capacitors (30) are about the same thickness of said plate member (11) so that said electrodes (32, 33) are coincident with the surfaces (14, 16) of said plate member (11).