SE455243B - ELECTRO-OPTIC CONNECTOR CONTAINING A SHELL COVERING AN ELECTRO-OPTIC ELEMENT WHICH WILL INCLUDE AN OPTIC ACTIVE CAVITY FILLED WITH A TRANSPARENT LIM. - Google Patents

Abstract

An electro-optical connector is provided in which an electro-optical element 4, accommodated in a housing 1, may be coupled to a light-conductive element 11. In order to obtain a small contact region with suitable optical and electrical conditions, the housing 1 is provided with openings 2, 2b for accommodating the electrical and optical parts which comprise guide means 3, 2a, 2d which reliably align the electrical and the light-conductive element 4, 11 with respect to each other (Figure 1).

Description

455 243 DE Offenlegungsschriften 2736ü60 describes an optoelectric device which comprises a guide tube and a housing containing a lens. This device also requires space. Details of such devices are described | DE Offenlegungsschrift Züüålkk, 3703fl65 och 2746å97. The solutions described in all of these scriptures are complex and contain many details.

It is also known to prepare an LED (LED) for connection to light-conducting elements in such a way that the plastic cover of an LED intended for lighting purposes is partially broken and the optical fiber is manually connected to the fragmented surfaces by two fastening steps. In this context, reference is made to the Opto-electronics Applications Manual, 1977, Heuñett-Packard Company, No. 34567890, HDHD 78654321098, page 2.53. The device shown requires great accuracy and a considerable time effort and is practically achievable only with thick optical fibers with a diameter equal to approximately 1 mm.

It is also known to attach light-sensitive or light-emitting chips (chip) to a metal plate and to carry out the necessary leads through the metal plate. In a known exemplary embodiment, the front side of the chip is exposed by a seal of transparent epoxy glass so that a plane-parallel surface is obtained with the chip. The mounting of the optical fiber on the front of the chip requires high accuracy and involves a complicated construction because the light emitting surface of the chip is very small.

It is also previously known to apply mechanized mounting of the optical fibers. A suitable metal tube is then arranged on the bottom part of metal on the light-emitting side of the chip and the optical fiber is glued to said tube in an insulating manner. This arrangement becomes complicated due to the many separate parts and the necessary, mutually adapted process steps.

It is also known to etch a hole into the light emitting chip so that the optical fiber can be inserted into this hole. Devices of this kind are only useful for laboratory purposes as series production is excluded by the necessary large work effort.

The objects to be aligned exactly in relation to each other in practice consist of very small chip plates comprising emitting or light-receiving surfaces on one side and the end surfaces of the optical fibers on the other side.

In order to achieve an appropriate connection, if possible, only one adaptation medium should be present between the two surfaces. In the case of an emitting or receiving surface of GAAs with a refractive index n = 3.6 on one side and an end surface of a quartz or plastic fiber on the other side, the fitting medium should suitably have a refractive index n = 1.8 . Since such a refractive index cannot be realized without further ado for technical reasons, a not as good but still acceptable result can be achieved with a slightly lower refractive index, eg n = 1.54, with 455 243 ::::: t: g: :: m :: lg :: nep :: yplast. As far as the technical realization is concerned, there are grids to realize the conditions for achieving suitable K flfl coverage, which is theoretically treated already in the said DE publications' This Same fl hä fl g fi f with the limited space in an electronic circuit Especially when a QPUPP HV Optical conductors are to be connected to such a circuit instead of only a single optical conductor.

The object of the invention is therefore to provide a contact point which is small in volume and can be accommodated in the small spaces present in electronic devices, while maintaining optimum optical conditions on the one hand and using known manufacturing methods for optoelectronic elements (chips). circuits both in the case of a single optical conductor and in the case of several optical conductors.

The object of the invention is achieved by a connector according to the first paragraph of the description, which is characterized in that the housing contains an optically active cavity which is filled with a transparent glue.

The arranged optically active cavity which is filled with a transparent glue prevents losses inside the housing.

According to the invention, the refractive index of the material of the casing can be chosen lower than the refractive index of the adhesive which joins the surfaces so that a fully reflective intermediate element (link) is formed in the cavity between the fiber end surface and the light-sensitive or light-emitting surface.

The cover can be made of material with a refractive index that is lower than the glue. For this purpose, the following substances are proposed: polyethylene, polypropylene, polytetrafluoroethylene, fluoroethylene-propylene, polyvinyl chloride, silicon rubber, while the adhesive, which simultaneously fills the space between the fiber end surface and the light-emitting or light-receiving surface, may consist of epoxy plastic.

An outer body of metal, for example molded zinc, is also conceivable, in which case the necessary electrical insulation is provided by the epoxy plastic adhesive.

The casing can be given such a small size that it can be fitted into a normal wiring harness, eg a wiring harness with the dimension l / 10 or 2/10 inches in the case of transverse mounting.

The contact pins, electrodes, etc. that leave the housing in the direction of the electrical shaft damper can be bent into an angled circuit so that they fit with the standard dimensions of a circuit board network. The diameters of the chips and the fibers are of the order of less than 1 mm, which means that even small mutual deviations between their axes can lead to a significant change in the coupling.

Therefore, in order to fix the mutual position of the parts, a flange of the same size as a chip can be arranged inside the housing, the chip being inserted into the flange so that ~ ~ ~ ~ «- u». ~ ... u .u- ä "455_ 243 the center of the chip, the longitudinal axis of the casing and the axis of the fiber are made to coincide.

The outside of the housing can be provided with coupling means for joining with similar housings.

In the following, some embodiments of the electro-optical connector according to the invention will be described in more detail with reference to the drawings, in which: jjg_1 shows an enlarged sectional view of an electro-optical connector according to the invention; Figs. shows on a further enlarged scale a second, special embodiment according to the invention of the part where an LED connects to a glass fiber; Figs. show on an enlarged scale a part of a third, prepared electro-optical connector comprising the electrical part but not the optical part; fjg_§ shows a plan view of a number of electro-optical connectors mounted on a printed circuit board; shows a side view of the electro-optical connectors shown in Fig. 4; fig_§ shows a number of interconnected connectors with modified housing.

Fig. 1 shows a housing 1 of synthetic material with a continuous bore 2. The bore 2 consists of a part 2a with a comparatively small diameter and a part Zb with a larger diameter equal to a multiple of the smaller diameter.

Part 2a opens out of the housing in the form of a funnel. Between the parts 2a and 2b there is a further part 2b with average diameter, which thereby forms a shoulder 3.

In the part 2b of the bore 2 there is an electro-optical transmission-receiving element in the form of a chip 4, for example a diode or the like, which is thereby located exactly opposite the part 2a. On the other hand, the chip 4 is connected by an electrical conductor 5 in the form of a gold wire to an electrode 6 by bonding, said electrode acting as a connection contact. On the other hand, the chip 4 is electrically connected to an electrode 7. The chip 4 is housed in a cavity 8 of the electrode 7, which acts as a concave mirror.

The electrode 7 also contains a holding tooth 9. The electrodes 6 and 7 are initially held together by means of a cam 10 which is removed after mounting the housing 1.

To provide the electro-optical coupling, an optical fiber 11 is inserted into the bore 2 so that it just inserts into the part 2d. Axial fixation is achieved by connecting to the part 2a of the bore 2. The chip 4 is inserted in the part Zb together with the electrodes 6 and 7 until the electrodes 6 and 7 abut against the shoulder 3 and the chip 4 is located in the middle of the end surface 11a of the optical fiber 11. After axial fixation, the divider 2b and 2d of the bore 2 are filled with an otic conductive adhesive 12. If desired, the fixation of the optical fiber 11 and the chip 4 can also take place simultaneously in one step. When the housing is made of a transparent material, eg PS, PMMA or the like, the instantaneous position of all parts in relation to each other can easily be observed during assembly. 455 243 The section 2d of the bore 2 prevents the electrical conductor 5 from causing a short circuit between the electrodes 6 and 7.

Fig. 2 shows a modified embodiment of the housing 1 according to the invention. Parts corresponding to Fig. 1 are provided with the same reference numerals but in this case are provided with an apostrophe.

Between the parts 2a 'and 2b' of the bore 2 'there is a projecting flange 20. In the flange 20 there is a slot 21 for the electrical conductor 5' which is inserted therein during assembly. As a result, a short circuit between the electrodes 6 'and 7' cannot occur. The cavity 8 'is shown in a partially sectioned view. The flange 20 projects slightly into the cavity 8 'and comprises a flat projection 2e. The chip 4 'is thus enclosed partly by the cavity 8' and partly by the projection 2e. The end face 11a 'of the optical fiber 11' is located just above the chip 4 '.

The conductor 5 'is connected laterally, so that unlike Fig. 1 the optical fiber 11 can be arranged directly on the surface of the chip 4', i.e. without any intermediate other medium.

This connection method is also called "butt joint". The sheath 11b is slightly shorter than the core 11c of the optical fiber 11.

By selecting suitable materials with different refractive indices it can be achieved that the groove 2a, i.e. the inner wall, has a refractive index n at the flange 20 which is lower than the refractive index of the adhesive 12 'which fills the gaps. This leads to total reflection. Joint deviations between the surface of the optical fiber 11 'and the chip 4' at the end surface 11a 'are hereby compensated to such an extent that energy radiating past the end surface 11a' of the optical fiber 11 'is reflected inwards again and in each case partly re-directed into the optical fiber.

The entire cavity is filled with the optically conductive adhesive 12 'in the manner already described with reference to Fig. 1. The lower part of the bore 2' has a tapered shape to provide control of the optical fiber 11 '.

The bore 2 'may be filled with glue of another kind if, for reasons of manufacture, it would be appropriate to first insert one of the two parts and fix it in advance. Suitable adhesives in this context are particularly fast adhesives based on cyanocrylate.

Fig. 3 shows a prepared and pre-assembled electro-optical coupling which already contains the electrical parts, but where the optical fiber is still missing. Couplings of this kind can be prefabricated in such a way that necessary couplings can be made without problems in the field. Components with equivalents in Figures 1 and 2 have the same reference numerals provided with apostrophe characters.

The housing 1 "comprises a bore 2" which, via a cone-shaped transition area 31, merges into a precisely dimensioned, cylindrical or cone-shaped neck bore 32. The section 2b contains the electrode 7 "whose holding cavity 455 243 8" surrounds the chip 4 "through the connecting mass. The bore 2" is filled with a transparent glue 12 "which penetrates to the surface 33 of the bore 32.

The adhesive 12 'itself contains a wire connection 34. The housing 1 "comprises a projecting flange 20' which holds the chip 4" in a recess 2e '. The adhesive 12 "not only provides hermetic closure of the chip 4" but also forms a short spacer by suitable material selection, which is formed above the surface of the chip 4 "by the adhesive 12" by partially filling the bore 32. If desired, the intermediate piece 35 can also be formed on the chip 4 before the insertion of the electrical part for connection to said chip.

The material used for the cover 1 "is a material whose refractive index is lower than that of the adhesive 12". This results in total reflection of energy-containing rays coming from the surface of the chip 4 "at the ends of the neck bore 32 below the surface 33. The surface 33 may be curved to produce this lens effect.

If the electro-optic connector is to be used for optical reception, the reflection in the surface 33, the neck bore 32 and the intermediate space 35 can be selected in such a way that light rays coming from the optical fiber and not shown in the drawing are reflected towards the chip 4 ". .

The electro-optical connector manufactured according to Fig. 3 can be mounted in any environment by simply filling the bore 2 "with glue and then inserting the optical fiber. The surface 33 of the intermediate space 35 or the surface of the chip 4", which is critical for a optical coupling, is suitably protected by the bore 32. The adhesive used for attaching the optical fiber 2 in the bore 2 "can also be optically adapted in such a way as to obtain a reliable protection against light loss when the light signal passes the borehole.

Figures 4 and 5 show a preferred arrangement of electro-optical connectors on a printed circuit board. The printed circuit board 41 comprises holes 42 and 43 arranged to form electrically conductive connection points through precipitated copper grooves. The electrodes 11 and 13 are bent at right angles, as can be seen from the side view in Fig. 5. The bent electrodes are inserted into the holes 42 and 43 and soldered.

In Fig. 6, the sides of the housing 1 "'are provided with coupling means in the form of salmontail-shaped recesses and projections 60, which make it possible to assemble a connector housing for, for example, a flat cable with several conductors or the like.

Claims (2)

~ 455,243 Patent claims. 1. An electro-optical connector comprising a housing enclosing an electro-optical element and comprising at least two electrical connections and at least one optical connection, the housing (1, 1 ", 1" ') being constructed as a single unit, consisting of an electrically and optionally optically insulating material and comprises at least two openings (2,2 ', 2 ", 2b, 2b', 2") for accommodating said electrical and optical connections which are arranged axially one after the other, the openings comprising guide means (3, 2U, 20 ', 2e, 2e') for mutual alignment of an electro-optical element (ü, H '# ") and a light-conducting element (11,1l') which is inserted into the apertures, characterized in that the housing (1, 1 ', 1 ", 1"') houses an optically active cavity (2d, 2e, 35) which is filled with a transparent glue (l2, l2 ', l2 ") Coupler according to claim 1, characterized in that the material in the casing has a refractive index which is lower than the refractive index of the adhesive, whereby the cavity between the fiber end surface and the light-sensitive or light-emitting surface has totally reflective walls.