DE2722367A1 - ARRANGEMENT FOR LOW-LOST ENCLOSURE OF THE ENDS OF LIGHT GUIDES OR LIGHT GUIDES - Google Patents

Description

DIP LO M-INOBNIBUR PATENT ADVOCATE

8ΟΟΟ MUNICH SO MAUKHKIHCIIBHSTK. 31

Combined Optical Industries Limited phone O8t> - »8ιοτο

200 Bath Road mix 022019

Slough

Berkshire SL1 4DW ^{| 7 <MAY W}

England

Arrangement for the low-loss termination of the ends of light guides or light guide bundles

The invention relates to an arrangement for the low-loss termination of the ends of, in particular, one another connecting light guides or light guide bundles. The invention also relates to a method for mutual connection of light guides or light guide bundles.

It is well known that the transmission of data via optical fiber optics in many respects considerable advantages over conventional electrical processes. These include a larger data capacity, the avoidance of interference, as occurs with electrical processes, the practically complete absence of a fire hazard and very low signal losses over long signal paths.

In principle, a continuously running light guide should be aimed for between the signal input and the signal output of a transmission path , but this is not the case

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is always practicable. For very long transmission distances Sufficient quantities of light guides are usually not available. In other cases it can be cheap be to extend a transmission system in the one further transmission path with fiber optics is added. It may also be necessary to use light guides in addition to be connected or disconnected.

Fasteners have already been proposed for this purpose. These are the ones to be connected to each other Ends of the light guide arranged coaxially and held in mutual contact with their end faces. Around To improve the connection, the end faces of the light guides are usually polished prior to connection to to get a visually perfect face.

Although this makes it possible to establish functional connections, these still leave something to be desired in terms of precise alignment and mutual contact of the fiber optic ends and the associated reliability. If, for example, two end faces do not touch one another, but are separated from one another by an air gap in the order of magnitude of half the light guide diameter, signal losses of at least 50% can occur. If the two light guide ends are shifted by a small angle of, for example, 5 ° with respect to the exact longitudinal alignment, a signal loss of 30 % can occur. If the end faces are laterally offset by 0.4 times the light guide diameter, for example, a loss of 50 % can occur.

The criterion of precise alignment and mutual contact of the fiber optic ends becomes very important if the connection made is exposed to vibrations or other movements or if detachable connections are provided. If the end faces of the light guides are damaged or if foreign matter is present

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Establishing the connection between the end faces, considerable signal losses occur.

So far, however, there are not only problems in connection with the connection of the light guide ends Effective light transmission occurred, but difficulties arose in achieving one Receiving element for the end of a light guide or light guide bundle with which the transmitted light is satisfactorily received, represented or emitted again can be.

The object of the invention is to provide a possibility for low-loss termination of the ends of light guides or light guide bundles, through which in particular the mutual connection of light guide ends is significantly improved.

An arrangement of the type mentioned is designed according to the invention to solve this problem in such a way that the respective end of a light guide or light guide bundle is inserted into a recess of a lens element. is set, which is arranged so that emerging from the end of the light guide or light guide bundle light is emitted from the lens element as a parallel bundle of rays.

The lens element is preferably made of a body

Formed by translucent material with two opposing surfaces, one surface bent in the shape of a lens and the other surface with the recess is provided. In the case of such an element, the body can, for example, be designed as a cylinder, one end of which surface lens-shaped and its other end face with the recess is provided.

The lens surface is preferably convex and the recess is arranged coaxially with the lens.

The linens element can also be used very advantageously

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a plastic molding can be formed.

A receiving element for the end of a light guide or light guide bundle is also within the scope of the invention provided that a lens element of the type described above within a housing and a device for holding a light guide or light guide bundle in the recess of the lens element.

Preferably, the receiving element also comprises an elastic device which is provided so that the Lens element when inserting the end of a light guide or light guide bundle into the recess against this Device can be relocated.

According to a preferred embodiment, the housing has the shape of an open tube, and the holding device is designed as a cap which is placed on one end of the tube and closes it. This cap has an opening through which the light guide or the light guide bundle to the lens element runs.

A connecting device for connecting two light guides or light guide bundles also includes Formation of the inventive concept two lens elements of the type described and a device for connection of the two lens elements with opposing lens surfaces, creating a parallel bundle of rays emitted by the one lens element and received by the other lens element and onto the one assigned to it The end of a light guide or light guide bundle is focused.

Preferably, the two lens elements are arranged coaxially in a tube that has one at each end wearing removable cap. Each cap has an opening through through which the respective light guide or the respective light guide bundle to the assigned lens element

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leads is.

The two lens elements can very advantageously be mounted displaceably in the axial direction in the tube and are kept separated from one another by an elastic element arranged between them.

A connecting device according to the invention can be dismantled, ie it contains the two lens elements in an open tube each, each tube having a removable cap with an opening at one end through which the respective light guide or the respective light guide bundle leads to the associated lens element is. Furthermore, a tubular sleeve is provided for receiving the two tubes in an axial alignment, the two lens elements facing one another with their lens surfaces. The two tubes can then be held releasably in the sleeve.

Finally, the invention provides a method for connecting two light guides or light guide bundles for the purpose of optical transmission, in which one end of each light guide or light guide bundle is inserted into the recess of a lens element which emits light transmitted via the light guide or light guide bundle as a parallel beam, and the two lens elements are arranged opposite one another , so that the parallel bundle of rays emitted by the one lens element is received by the other lens element and focused on the light guide end or light guide bundle end connected to it.

The two lens elements can be mounted coaxially in a tube which is provided with a removable cap at each end. Each cap has an opening through which the respective light guide or

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the respective light guide bundle is guided to the associated lens element. The tube is used as a holder of the two lens elements in the predetermined position, which is normally such that practically the whole parallel bundle of rays emitted by one lens element enters and from the other lens element is focused. In order to prevent any possibility of lateral light loss or light entry, this is Tube preferably opaque. It is advantageously made of plastic, although other materials are also used here, metals, for example, can be used.

Each cap can be used to hold the respective lens element in the tube and also to guide and hold it of the incoming light guide or light guide bundle are used. A pillow for each is advantageous for this purpose Associated cap which is provided so that it the respective light guide or the respective light guide bundle engages when the respective cap is placed on the end of the tube. At the same time, the The light guide or the light guide bundle is pushed completely into the recess of the associated lens element. A suitable cushion element consists, for example, of a neoprene insert (or a other material) with a central hole to accommodate the light guide (s) and an outer contour, which is adapted to the inside of the pipe. This causes pressure to act on this cushion when the cap is put on grasping and holding the light guide (s). A forward movement of the cap on the tube is with pressing the light guide or light guides into the tube down to the bottom of the recess of the associated Lens element connected.

To align the end or ends of the light guide (s) with the associated lens and dimensional tolerances to compensate, for example, by temperature changes

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may be caused, and also to eliminate any compressive forces that may exist in the light guide or light guide bundle when the cap is pressed into the recess of the lens, is the lens element preferably displaceable in the axial direction in the associated tube. Several lens elements are involved kept separated from one another by an elastic element, for example by a spring.

Connection devices according to the invention can be so-called "one-time connections" or they can be dismantled be provided. In the latter case, the two lens elements are coaxial in one open each Tube and each tube is fitted with a removable cap at one end. To manufacture the Connection, the two tubes with the light guides attached are pushed into a sleeve, wherein the two lenses are arranged opposite one another. There are releasable connections to the bracket of the tubes provided in the sleeve. The connections can be in the form of a releasable lock, for example be designed as bayonet locks. To solve them, they are opened so that one or both tubes can be removed from the sleeve.

In a connecting device or a receiving element according to the invention, the lens elements are preferably designed as cylindrical solid bodies, one end face of which is lens-shaped and the other end face is provided with a recess into which the end of a light guide or light guide bundle is inserted. Such an arrangement is particularly advantageous for several reasons. Through them, the lens surface itself for generating a parallel beam and the recess for receiving the light guide end is realized with a single element (very advantageously a molded plastic piece). This can therefore be very precise

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be arranged in a predetermined position already during manufacture relative to the lens surface, so that the Always automatically the end of the light guide or light guide bundle when it is fully inserted into the recess is precisely positioned. The beam cone emitted by the end of the light guide is precisely collected by the lens, and conversely, a parallel bundle of rays picked up by the lens element is exactly on that Focused on the end of the light guide or introduced into it. This automatic precise positioning of the end a light guide or bundle of light guides by simply pushing it into a recess is a special feature is an advantageous feature since no particular skill is required for this simple process.

One of the main problems with previous connection devices and receiving elements, namely the exact positioning the light guide ends is thus solved in the invention in a simple and elegant manner. The lens elements themselves can be manufactured very accurately and relatively cheaply with the recess present therein by for example a plastic injection molding process is used.

Further advantages result from the use of lens elements of this type in terms of precise alignment two lens elements. This is achieved very simply by having the lens elements in a single Pipe that is exactly straight. The two lens elements are then automatically aligned and also protected against contamination or damage. By attaching the lens elements in a tube can also easily be carried out an axial relative movement of the lens elements without misalignment is to be feared.

A third advantage of the lens elements is that practically all of a light pipe can be used

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or light guide bundle emitted light is converted into a parallel bundle of rays, which means that practical no light loss occurs. This is achieved by a lens surface whose diameter is sufficient is to accommodate the entire cone of rays emerging from the end of a light guide or light guide bundle. Furthermore, in particular when using an optical coupling liquid because of the direct entry of light from the end of the light guide into the lens element and the light guide to the lens surface the light losses are eliminated, for example, by reflection at intermediate surfaces. The unitary lens element forms a homogeneous, continuous light transmission medium, which makes internal light losses practical can be completely avoided, which could, however, occur if, for example, a lens were used that is derived from a light guide end is separated, or if several interfaces would be present in the beam path.

An optical coupling liquid is preferably used when the light guide or the light guide bundle is inserted into the recess of the lens element. Such liquids are known, for example polyethylene silicone can be used. The use of such a liquid leads to a further improvement in transmission, and at the same time there is no need to polish the end faces of the light guides to create an optically perfect surface. Therefore, the recess of each lens element should preferably have an inner part with a diameter which corresponds fairly exactly to that of the light guide or light guide bundle to be received, and furthermore an outer part of larger diameter should be provided, which absorbs any excess optical liquid that comes from the inner part is pushed out when inserting the light guide or light guide bundle .

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The lens elements themselves can be made of glass, but usually it will be better to make them of one Manufacture plastic such as polystyrene or polymethyl methacrylate. The lens elements can be made from these substances be shaped.

The receiving elements according to the invention are used to connect the end of a light guide or light guide bundle. They protect the sensitive ends and deliver a parallel beam as an output signal during operation. For example, this output signal can be routed to a display or reading device or to a further transmission device. In the latter case, the receiving element can form one half of a releasable connecting device according to the invention.

In the present description, a light guide or a light guide bundle is to be understood as meaning arrangements which can have light guides of any thickness, so that the use of light guide fibers is also included individually or in bundles.

Embodiments of the invention are described below with reference to the figures. 1 shows the section of a lens element, FIG. 2 shows a connecting device with inserted light conductors,

Fig. 3 shows a further connecting device with inserted optical fibers and
4 shows a receiving element for light guides.

1 shows a lens element which consists of a cylindrical solid body 1 which, for example, can be formed from polystyrene by an injection molding process. An end face 2 of this body 1 is curved so that it has the effect of a lens. At the other end 3 there is a recess with a conical outer part 4, a middle part running slightly obliquely

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Part 5 and an inner, narrow part 6 which ends at a surface 7 is provided. This can be optically polished be, it is flat and is divided in the middle by the longitudinal axis of the lens element. The area 2 is normally optically polished. If an optical fiber bundle is used, the dimensions of the parts are 5 »6 and 7 chosen accordingly larger.

The surface 7 lies in the focal point of the lens surface 2. The lens surface 2 can be spherical or aspherical, which depends on the desired transmission properties.

In FIGS. 2 and 3, in which the same reference numerals as in the other figures are used, two lens elements 1 of the type shown in FIG. 1 are provided in a tube 10 opposite one another and axially aligned with one another. The lens elements 1 can be displaced in the axial direction in the tube 10 and are pushed apart by a light compression spring 11 which is arranged between them. At each end of the tube 10 a cap 12 is provided which has an opening 13 through which the light guide 16 or a corresponding light guide bundle is passed. Each cap 12 is placed on one end of the tube 10 and can be fastened in this position, for example, with a thread (not shown) or another holding element. A cushion or pad 14, which in the present case consists of neoprene, is arranged in each cap and has a truncated cone shape which is adapted to an element 15 which serves as a seat for the pad 14.

To make the connection, the caps 12 are removed from the tube 10 together with the pads 14 and the seats 15. The light cords or light guide bundles that are to be connected to one another are preferably polished so that they have an optically perfect face, and the usual plastic cover is withdrawn,

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to expose the light guide itself. The cap, the cushion and the seat are pushed onto the light guide, and a small amount of optical liquid is passed through onto the end of the light guide for example Immersion applied. The end of the light guide is inserted into the recess 6, after which the cap with The upholstery and seat are placed on the tube. As the cap moves to its predetermined position, the pad is compressed around the light guide or the light guide bundle and holds it under at the same time further pushing into the recess 6 against the surface 7. When the end of the light guide the Touches surface 7, a further inward movement of the light guide causes a displacement of the lens element in the axial direction against the force of the spring 11. The cap is finally in its predetermined Position, the light guide is held tightly in the recess of the lens element, and its in The end face immersed in the optical liquid rests in contact with the face 7. Excess fluid is pressed into parts 5 and 4 of the recess.

When both caps are on, the connection is established. That from the end of a light guide or The light emerging from the bundle of light guides reaches the associated lens element in the form of a precisely defined beam cone and is emitted as a parallel bundle of rays. This runs through the pipe 10 to the other Lens element, where it is focused on the end of the light guide or light guide bundle connected there.

In the device shown in Fig. 3, each lens element is arranged in a tube 20, which is practically corresponds to half of the tube 10 in FIG. 2, with the difference that each tube 20 has an annular cushion seat 21 has at one end which is formed integrally with the tube. The neoprene pad 22 is opposite

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the cushion 14 according to FIG. 2 correspondingly shaped somewhat differently. Both tubes 20 are in a sliding fit in one Sleeve 23 out, and detachable fastening elements 24, in the illustrated embodiment bayonet locks, hold the pipes in place.

Caps 12 are provided on the upholstered seats 21. At the inner end of each tube 20 is an elastic one Disc 25 is provided, which allows an axial movement of each lens element 1 during the insertion of a light guide allows and compensates for dimensional changes after assembly, for example due to temperature changes can be caused.

The assembly of the connection according to Fig. 3 is carried out as follows. The light guides or light guide bundles are fastened in the lens elements and held by the caps, as has already been described with reference to FIG. Each tube 20 is then inserted into the sleeve 23 and locked there by the bayonet catch. This completes the connection. The solution is achieved simply by removing one or both tubes 20 from the sleeve 23.

FIG. 4 shows a receiving element which is practically one half of the connecting device shown in FIG. The same reference numerals are used here as in FIG. 3.

The invention makes the previously required accuracy of many individual parts superfluous, and the difficulties and disadvantages associated therewith are avoided. In contrast to the previous connections , the distance between the ends of the light guides or light guide bundles is no longer critical in a connection according to the invention.

The axially displaceable Linsenele elements center the light guides and compensate for dimensional changes that can occur during manufacture and operation.

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With connections according to the invention a very easy assembly is possible, with an automatic accurate Positioning the light guide ends results.

Arrangements according to the invention can also be produced relatively simply and easily .

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Claims (20)

Combined Optical Industries Limited 2722367 Bath Road en ν. 1? · ΜΑ1 | 9/7 Slough Berkshire SL 1 4DW 3C1 1177 England claims 1. Arrangement for the low-loss termination of the ends of in particular light guides or light guide bundles to be connected to one another, characterized in that the respective end of a light guide or light guide bundle (16) into a recess (6) of a lens element (1) is inserted, which is arranged so that from the end of the light guide or light guide bundle (16) emerging light from the lens element (1) is emitted as a parallel bundle of rays. 2. Arrangement according to claim 1, characterized in that the lens element consists of a body (1) made of translucent Material with two end faces (2, 3) consists of which one is lenticular and the other is provided with the recess (6). 3. Arrangement according to claim 2, characterized in that the body (1) of the lens element is cylindrical is and at its one end the lenticular face (2) and at the other end the one with the recess (6) provided end face (3). 4. Arrangement according to claim 1, 2 or 3 »characterized in that the lens-shaped end face (2) is convex is formed and that the recess (6) is arranged coaxially to the lens-shaped end face (2). ORIGINAL INSPECTED 5. Arrangement according to one of the preceding claims, characterized ^ indicates that the recess has an inner Part (6) with a diameter corresponding to the diameter of a light guide or light guide bundle (16) and an outer part (4) of larger diameter. 6. Arrangement according to claim 5, characterized in that the bottom surface (7) of the inner part (6) of the recess is flat and optically polished. 7. Arrangement according to one of the preceding claims, characterized in that the lens element (1) is a Plastic molding is. 8. Receiving element for the end of a light guide or Light guide bundle with a lens element according to one of the preceding claims, characterized in that that the lens element (1) is arranged in a housing (20) and that a device (12) for holding of the end of a light guide or light guide bundle (16) is provided in the recess of the lens element (1) is. 9 · Receiving element according to claim 8, characterized in that an elastic device (14) is provided, a displacement of the lens element (1) when inserting the end of a light guide or light guide bundle (16) into the recess (6). 10. Receiving element according to claim 8 or 9, characterized in that the housing (20) is tubular and that the holding device (12) is a cap placed on one end of the tube (20) which has an opening (13) through which the light guide or the light guide bundle (16) is guided through to the lens element (1).
709849/0859 11. Receiving element according to claim 10, characterized in that the cap (12) is assigned a cushion element (14) is that the light guide or the light guide bundle (16) when placing the cap (12) on one end of the tube (20) and completely into the recess (6) of the lens element (1). 12. Connection device for the mutual connection of two light guides or light guide bundles using two lens elements according to one of claims 1 to 7, characterized in that one device (10) for holding the two lens elements (1) with opposing lens-shaped end faces (2) is provided in such a way that a parallel beam of rays emitted by the one lens element (1) added to the other lens element (1) and on the associated light guide end is focused. 13. Connecting device according to claim 12, characterized in that that the two lens elements (1) are arranged coaxially in a tube (10) at each end is provided with a removable cap (12), and that each cap (12) has an opening (13) through through the respective light guide or the respective light guide bundle (16) to the respectively assigned Lens element (1) is guided. 14. Connecting device according to claim 13, characterized in that that the two lens elements (1) in the axial direction in the tube (10) and displaceable are held at a distance by an elastic element (11) arranged between them. 709849/0859 15. Connecting device according to claim 13 or 14, characterized characterized in that the two lens elements (1) are each arranged in an open tube (20), which at its end with a removable cap (12) is provided, which has an opening (13) for implementation a light guide or light guide bundle (16) to the respectively assigned lens element (1), and that a tubular sleeve (23) for receiving the two open tubes (20) in axial alignment and with opposing lens surfaces of the two lens elements (1) is provided, which the two holds open tubes (20) releasably. 16. Connecting device according to claim 15, characterized in that that at least one bayonet device (24) is provided for holding the two open tubes (20) is. 17. Connecting device according to claim 15 or 16, characterized in that each lens element (1) slidable in each tube (20) relative to an elastic device (14) at the other end of the tube (20) is. 18. Connecting device according to one of claims 12 to 17, characterized in that each cap (12) a cushion element (14) is assigned to the respective light guide or the respective light guide bundle (16) holds and when the cap (12) is placed on the end of the respective tube (20) completely moved into the recess (6) of the respectively assigned lens element (1). 709849/0869 19. Connecting device according to one of claims 12 to 18, characterized in that each lens element (1) is a plastic molding. 20. Method for the mutual connection of two light guides or light guide bundles for the optical Signal transmission, characterized in that one end of each light guide or light guide bundle is inserted into a recess of a lens element which is designed so that it is of the light guide or emits light emitted from the light guide bundle as a parallel bundle of rays, and that the two Lens elements are arranged opposite one another, so that the emitted from the one lens element parallel bundles of rays taken from the other lens element and onto the end connected therewith of the light guide or light guide bundle is focused. 709849 / 08S9