DE2151781A1 - Optical light guide - made by depositing optically conductive copolymer on insulating substrate - Google Patents

Abstract

An optical light guide is produced by applying an optically conductive layer in the desired pattern configuration to the surface of an optically insulating substrate. The pattern can be formed by grooves in the latter which are filled out with an optical conductor by casting or growing. A prefd. method is rolling or pressing the pattern from a sandwich made up of a conductive and an insulating foil.

Description

Process for the production of light guides and light guide assemblies The invention relates to optical and electron-optical communication media, in particular a method for producing light guides and a light guide arrangement used in various fields of optoelectronics, especially in the Manufacture of integrating optical and optoelectronic devices such as z. P, different logical systems can be used in which the information transfer done with the help of rays of light.

It is known that information is transmitted by means of a light signal optical systems made up of individual optically isolated cylindrical fibers (optical elements) are formed, the latter in a predetermined Order to be connected to a fiber optic cable0 Especially in logical systems it is necessary in the transmission of information to carry part of the information Derive light radiation sideways through different channels as well as the distance between the Optical fibers must be strictly observed from each other0 Used for the construction of such systems one a process in which the main light guide to form a branch a side light guide is connected at a certain point. The connection takes place by gluing or melting. But there can be no high-quality optical Contact will be guaranteed; the melting can also damage the light guide structure to lead.

The narrowly limited group of substances used to carry this out Method are appropriate (and this method implies the use of draggable Fabrics advance), as well as the inability to create changeable geometric shapes or different Maintaining component content along the light guide are also deficiencies of the procedure mentioned.

Finally, the connection of the elements with fiber structures offers to non-fibrous elements such as radiators, Receivers, modulators special manufacturing difficulties and is currently practically carried out by hand.

The invention is based on the object while reducing the A method of making light guides with any of the above mentioned shortcomings to develop specified forms and thereby the group of responsible for the manufacture of the Light guides to expand suitable materials, the production of light guides with variable geometric shapes or with different content of components along the light guide to enable and requirements for mechanization to create the production of light guide assemblies This task is at a Process for the production of light guides with a light-guiding element that is surrounded by optically isolating elements, solved according to the invention by that the production of the light-guiding element by applying a light-guiding Layer in the manner of a branched corresponding to the predetermined light guide shape Pattern on the inner surface of at least one of layers takes place, which is considered to be optical insulating elements are used.

When producing light guides, at least one can be optically insulating layer formed grooves corresponding to the predetermined shape of the light guide which are then filled with an optically conductive substance.

In the mechanical production of light guides will at least two formed by an optically insulating and a light-conducting film Layers pressed in with a tool, the surface of which is one of the specified Light guide shape has corresponding relief; A separately shaped branched one The fiber optic system is to be surrounded by optically insulating coatings, inside of the optically insulating material, figure cavities are to be formed be filled by -light-guiding material0 The light-guiding material to be applied The length of the material or its cross-section may be less than optical Have characteristic values0 When forming grooves or cavities in the optically insulating Layer, the light-conducting layer is formed as a film that covers the surfaces of the grooves n of the optically isolating die.

A light guide can be produced by growing crystals on a base be0 You can use the crystal layer with a larger refractive index from which z. BG a branched light guide is formed by etching, with an optically insulating Cover layer. Crystals that form a light guide can be grown in grooves that are created in the base beforehand 0 For the production of light guides becomes an optical one conductive photosensitive layer by a predetermined one Pattern exposed, developed and fixed, with unexposed sections one through Form optically insulating layer limited light guide with the desired shape0 One produced by means of the method according to the invention and its modifications Light guide arrangement has a profiled branched light guide, the one represents uniform light-guiding layer and of an optically insulating Fabric is surrounded0 With such a light guide arrangement in the optically insulating layer built-in electrodes and elements of an electrical circuit which together with the light guide arrangement optoelectronic devices form.

The inventive method for producing individual light guides, branched (profiled) light guide and whole optical and optoelectronic Equipment has a number of advantages compared to known methods on, as it enables the manufacture of light guides with rectangular and acute-angled Cross-section as well as optical fiber systems, and also branched systems without manual processing and in any large series of identical products In addition, this process allows new groups for the production of light guides of materials to use (previously only drawable Substances used). With the method according to the invention is also the Fig. 6 a, b and c different manufacturing stages of spatial light guides; -Fig. 7th a, b, c and -d another manufacturing variant for spatial light filters; Fig. 8 a, b and c different stages in the manufacture of light guides of larger dimensions; 9, 10 and 11 different variants of the method for producing hollow light guides; FIGS. 12 a and b show a multilayer light guide; 13 a and b show a method for the production of light guides using a model; Figs. 14 and 15 a Process for making "printed" light guide assemblies.

Embodiment 1 on a dielectric plate 1 (Fig0 1 a) with a refractive index nl and a low absorption coefficient (i.e. with Transparency conditions) becomes a light-guiding member 2 in the form of a Applied to a strip of transparent fabric with a refractive index n2, where n2> nl. The one applied on the basis of a given light pipe sketch light-conducting element 2 thus forms the desired, possibly branched one Light guide.

Manufacture of light guides with any variable profile as well as with variable optical properties according to the length or cross-section of the light guide possible.

Another possibility arises for the connection of light lines with non-optical elements such as emitters, receivers, deflectors, modulators etc. In the following description of exemplary embodiments for the production the light guide and with reference to the accompanying drawing, the invention is explained in more detail.

1 a and b show a branched light guide which produced by applying a photoconductive substance to a plate; Fig. 2 a, b, c and d show the cross section of a light-ic conductor with improved optical Isolation, as well as various stages of its manufacture; Fig. 3 a, b, c and d different Stages in the production of a light guide arrangement by etching; -Fig. 4 a, b, c, d, e and f different manufacturing stages of a light guide device with multilayer Arrangement of light guides; 5 a, b, c and d show different stages of manufacture - of light guides with a given cross-section; and the methacrylic series use after the substances have been chosen according to their relative refractive indices are0 For covering the surface of the light guide pattern one can use the fabric use the plate or any other material with a refractive index, which is smaller than that of the light guide strip.

When using melted, refractory materials (glass, Quartz) both the melting temperatures must be matched (for the plate one takes a substance with a higher melting temperature and / or higher viscosity) as well as the coefficients of thermal expansion in the entire operating temperature range are consistent to be brought. If you take glasses with approximately the same softening temperatures, so you can on the material of the plate strips of a substance with greater viscosity than with the panel material, which causes the material to be applied to flow away on the plate is prevented.

The fiber optic wires can vary depending on viscosity and density Countersunk completely or partially in the material of the plate.

The preprogrammed change in cross-section for the light guide strip (or in the case of the fiber optic cable) is carried out by changing the speed of the casting head. A branch can either be made by dividing the material flow to be injected be formed into two branches by e.g. B.

two watering heads that have poured a strip are gradually diverging, and a separation device is introduced into the flow from the outside, which it in presented The plate 1, the light guide produced in this way (or other glued, inserted into cavities or otherwise fastened elements) is completely or partially covered with a transparent protective layer 3 coated, the substance of which has a refractive index wn3, where n3 <n2.

The light guides can be applied to the plate as follows. They can be made from a solution or a melt to form a light-conducting Strip certain material by means of a guided according to a fixed program Casting head can be pressed in or poured. The thickness and height of the strip depends on the speed with which the strip is pressed in and the Casting head is guided by the material viscosity, curing time and the adhesive forceO All of these parameters can be varied within wide limits and thus a light guide thickness obtained from a few micrometers to a few centimeters.

For the production of light guides one can use one from the niche polymer Polybutyl methacrylate (n1 = 1.47) made sheet of any thickness and shape use, whereby the light-guiding strip is made of a solution or 1 of a melt of a styrene mixed polymer (n2 = 1.59) or from a mixture which give the weight fractions of components the required size of n1. For the method described and for the methods explained below for Manufacture of optical devices can be made from all acrylic polymers relationship and divides at a given speed, or one forms a branch by to press a new wire into a certain point of the pressed-in light guide begins, When pressing in, the composition of the light guide strip (or -ad) can be changed. For example, you can use the percentage composition of a mixture of styrene and methyl methacrylate copolymers change into the mixed polymers Chelates of rare earth elements to form fiber optic subsections introduce that are capable of induced emission, incorporate neodymium atoms into the glass etc.

Embodiment 2 To improve the optical isolation of The light guides can be used for light guides and / or to reduce their aperture produce additional dielectric sheaths which have a refractive index n ', where nl <n '<n2 should be. For example, aaf becomes one made of polybutyl methacrylate produced plate 4 (n ') according to Fig.

2 an at least 2 to 5 μm thick strip 5 made of polymethyl methacrylate (n1), which is slightly wider than the light guide, is applied to the light guide Core 2 made from the styrene mixed polymer (n2) or from a mixture of styrene-methyl methacrylate copolymers laid, and this arrangement is made from above and from the sides in the same way potted with a methyl methacrylate copolymer.

This ends the formation of the light guide sleeve. The whole arrangement can be poured from above with a butyl methacrylate mixed polymer, the one outer coating forms.

Embodiment 3 On a dielectric plate 1 (Fig. 3 a) With a refractive index n1, a film is applied that has a refractive index n2 and a thickness of at least several light wavelengths of the one to be used afterwards Has spectral range. A stencil or mask is placed on this film 7 (Fig. 3 b), and unnecessary film areas are etched away (Fig. 3 c). The formed light guide arrangement is covered from above with a protective layer 1 ' (Fig. 3 d) coated from a substance with the refractive index n1, one can do a similar thing also produce multilayer light guides according to FIGS. 4 a, b, c and d. On one through The plate 1 marked with the refractive index n1 becomes a film 6 with the refractive index n2 plotted, where n2? nl should be. A mask 7 is then placed on this film dusted up, and it is etched. The structure obtained is then covered with a film 6 coated from a substance characterized by the refractive index n3, where n3> n2. Again a mask 7 t is sputtered and the foil is etched. The conductor arrangement produced can be coated with an optically insulating layer 1 ' z. B. made of the same material as in the plate 1 are covered.

The initial foils can be poured onto the plate in a high vacuum or dusting of substances that are described in the description of the first exemplary embodiment mentioned. The mask required for etching can be made of metal (e.g. silver, Aluminum).

Polymers are etched with solvents (benzene, toluene, Xylene, their mixtures, etc.) or with glass-dissolving acids (e.g. with hydrofluoric acid etc.) AusfUhrungsbeispiel 4 fiber optic cores made of all the materials mentioned can be Dust on a plate serving as a base in a high vacuum through a stencil or pour from openings in the stencil if the substances mentioned do not adhere with the material of the stencil, by using a different stencil, other Substances can be dusted on or potted, with which one can form the light guide pattern continues. In a similar way, electrically conductive elements can be placed on the plate dust up, that is, printed electronic and optoelectronic devices form. A printed circuit prepared in this way is shown from above with doused optically insulating materials.

AusfUhrungsbeispiel 5 Optical arrangements with exactly to be observed Light guide cross-sections, e.g. B with square, triangular, hexagonal or round light guides (Fig. 5 a), can be produced as follows: In the as a substrate Serving plate 1 are groove systems 8 with the desired shape and predetermined profile (Fig. 5 b) formed. The plate is then doused with the material for light guide veins (Fig. 5 c), which fills the grooves. After hardening, the superfluous material is removed, and one thus obtains the finished optical arrangement (FIG. 5 c), which from above with an optically insulating coating 3 can be covered (Fig0 5 d) o The Nutensyieme can be produced by any process (casting of plates with grooves, Impressions, etching, photolithography, cutting out, etc. Plates made of materials used in the description of the exemplary embodiment 1 were mentioned. The grooves are filled by watering, depending on the selected substances in a noble gas atmosphere, in a vacuum, etc., by sputtering, etc.

Example 6 For the production of spatial light guides a die 9 is used (FIG. 6 a), the material of which does not adhere to the substance light-conducting element may have. In the die 9 grooves 10 are desired Profile executed. For the production of the die you can, for. 3. one under the Trade name "Ftoroplast" (fluoroplastic) use known fabric or glass. In The grooves 10 are any copolymer blends of the acrylic or methacrylic series or poured styrene copolymers and by means of a press ram i1 pressed. The structure formed in the die (FIG. 6 b) is then removed and coated with a thin shell by immersion in a mixed polymer solution. The structure is then brought into an appropriate position in space and formed an optically insulating layer covered with a light-insulating substance. A spatial light guide arrangement is thus obtained.

A light guide or a light guide arrangement can also be used according to Fig. 7 produce. One made from a material with the refractive index n2 Band 13 is by means of a die 14 and a punch 15 when necessary Heating punched to get the profile you want. The finished profile tape 13 'is removed and z. B. by immersion in a mixed polymer solution with covered with a thin sheath to achieve the initial stiffness of the tape Then the tape is used to form an optical isolator 16 with a light isolating Shed substance that has a refractive index n2, where n2 should be> n1, exemplary embodiment 7 When producing light guide arrangements and light guides with great length as well as in the transition to a continuous process of fiber optic production proceed as follows: From a light-conducting and an optically isolating one material strips with the required thickness are produced.

These ribbons are put together in such a way that the one light-conducting Fabric with the refractive index n2 fabricated tape 17 on the tape 18 from an optical insulating material with the refractive index n1 at n2> n1 or between the Ribbons 18 and 19 is arranged, which are made of substances with refractive indices n1 or respectively n3 are made and serve as an outer shell. The 11 sandwich formed in this way " (Fig. 8 a) is between not shown profile rollers with a relief pattern rolled, which presses the desired light guide systems (Fig. 8 b, c) into the strips, or is pressed with a profile punch.

The tapes with the thickness of 2 to 5 / um and more can be made of fabrics produce, which were mentioned in embodiment 1.

The initial sandwich can also be made from each optically transparent and polymer dissolved in a solvent or from a prepolymer Pouring a non-adherent surface, e.g. B. a film-like base made of Ftoroplast or polyethylene terephthalate, through a flat nozzle and by changing the substances intended for casting are produced. You can also have a sandwich by centrifuging a polymer on the same support.

Can be used to improve adhesion and the necessary softening the tapes are treated with heat when they are processed0 individual layers can be shielded from each other by a metal foil, by on dusting or chemically (electrolytically with AgN03, etc.) metallized0 embodiment 8 If the light-conducting wire and its sheath are made of polymers, it takes place a mutual partial diffusion of the core and the Shell fabrics. In this way, light guides are produced that have a cross-section Have zones with continuous refractive index change; Such a refractive cladding increases the light transmission of the system, as it increases the number of reflections from the boundary between the core material and the shell with inevitable light losses is decreased.

Exemplary embodiment 9 One way of improving the light transmission of light guides and light guide arrangements as well as their cooling results from Manufacture of hollow light guides. The light transmission is with these light guides improved because the light part of its way in the light guide not in the absorbing - The light guides can be cooled by using a refrigerant, z. B. helium because of its low viscosity, the cavities of these light guides can flow through.

Such light guide systems are produced as follows: On the Plate 20 (Fig0 9 a) with a refractive index n1, a film coating is applied, which has a refractive index n2. One presses grooves that correspond to the arrangement of the Optical fibers correspond (Fig. 9 b), and the superfluous outer film areas are removed, for example, by polishing (FIG. 9 c) O The light guide arrangement produced is coated with successive layers 22 and 23 (Fig. 9 d), their refractive indices n2 and n3.

In another embodiment of the inventively developed Method (Fig. 10 a, b, c and d) are in the plate 24, the material of which a Refractive index results in n1, grooves created. On the walls and on the bottom of the Grooves a thin light-guiding layer 25 with a refractive index n2 (n2> n1) dusted on0 The unnecessary parts of this layer lying outside the grooves are then removed and the fabricated structure becomes with layers 22 and 23 covered, whose refractive indices are respectively n2 and n1, where n2> n1 is.

The light-conducting film can also be covered in the grooves of the plate, as shown in Fig. 11 a, b and c. For this purpose, a plane is used Foil 25 placed on the surface of the plate 24 and a pressure at the appropriate Warming pressed into the grooves.

Then the superfluous film is removed outside the grooves, and you cover the generated structure, like has been described above, with layers 22 and 23.

After the substances have been applied to panels, the multilayer must be produced Structure in all mentioned cases of heat treatment in a furnace or a Thermostats are subjected to depending on the duration of treatment or temperature change the melt is cooled or volatile components are removed solutions become at different speeds and from different depths of the material in some processing stage the adjustment of the substance diffusion of a constituent of the system necessary to another, this can be achieved by one brings the products into a solvent atmosphere, all in the working examples 1 to 9 described methods can be used for the production of light guide assemblies use in metal matrices. However, if the light guides do not have an additional cover, the light permeability of such systems is low even with directional reflection.

Such cases are easy to manufacture if you put them in the Embodiments 2, 4, 7, 9 described method used.

Embodiment 10 When the produced light guide plates are put together with the light-conducting elements indicated by dashed lines in FIG. 12 or at Production of new light guide systems on coatings of the systems already produced multilayer optoelectronic devices are obtained. Three-dimensional optical systems can be made as follows: a) In a merged set of flat systems Transition light guides are formed, for example by drilling or melting through etc. in the set produces cavities, which are then filled with a light-conducting substance will.

b) With the help of a game 6 described for example in Ausführungsbei Process, individual light guide systems are produced. These systems will then distributed in the room and covered with an optically insulating material with a lower melting temperature shed.

c) A spatial model (Fig. 13 a) is produced, which the corresponds to the desired shape of the light guide.

The model is made with a substance that does not adhere to the model material encapsulated with a refractive index n1. The model is then removed and the resulting cavities are filled with a substance (Fig. 13 b), which by a Refractive index n2 is characterized.

When performing this method using a model the following materials can be used: a) Ftoroplast or polyethylene terephthalate fibers with an exact cylindrical shape or with a slight conicity will Cast with butyl methacrylate copolymers. The fibers are then removed and potted the cavities with methyl methacrylate.

b) Polyvinyl alcohol fibers are potted with the same substance and afterwards dissolved in water, c) rubbed with graphite paste to avoid adhesion Metal threads are encapsulated with glass. Large metal shrinkage makes removal easier of the threads, which can also be etched off. Embodiment 11 Light guide arrangements can also be produced inside a crystalline substance. Be for this purpose in the crystal areas with prescribed dimensions and with another (larger) Refractive index formed and thereby created conditions for the propagation of light.

Embodiments of such arrangements are considered below: a) A crystal layer of a compound is epitaxial on a crystal another connection.

For example, an epitaxial layer is applied to an NaCl crystal of NaBr, whose refractive index is greater than that of NaCl. In the NaBr layer areas with predetermined shapes are etched away so that only fiber optic wires remain. This blank is covered from above with an epitaxial layer made of NaCl.

b) The blank provided with the required surface pattern NaCl is made into a supersaturated solution of NaBr (or NaCl with additives to ensure of a different refractive index n). The monolith created with cut out and filled with NaBr figures (fiber optic veins) is in a supersaturated NaCl solution to form a surface coating with a smaller n submerged.

The remaining additions that are used to create other elements of the light guide assembly are necessary can be introduced using planar and thin film technology will.

For the production of microelectronic circuits and devices the following areas can be formed inside the same crystal: 1) areas with active additives to lasers or similar elements in these areas of the monolith circuit to create; 2) Areas with pn junctions and similar structures if the monolith block is made of semiconductor materials; 3) Areas with additions that a requested ensure electrical conductivity; 4) Areas with accessories that use electroluminescent lamps etc. form.

Embodiment 12 The simplest method for producing "Printed" light guide assemblies consists of the following: One uses one made of polymers or plate made of glass 26 (Fig. 14 a) with an applied photosensitive layer 27. After exposure of the plate through a mask 28 as well transparent areas remain on the plate after development and fixation the refractive index of the plate is less than the refractive index of the developed clear Layer so these see-through areas can be.

the photo layer with the appropriate choice of its geometric shapes serve as light guide arrangements0 The light-sensitive layer can be used from above with an optical isolator 29 (Fig. 14c) are coated0 If one is considered to be photosensitive If element-thick emulsion layers 30 (FIG. 15) are used, the glass substrate can be omitted. After the mentioned treatment, the photosensitive element is in an optical Embedded insulator.

One shortcoming of such devices is their light transmission is low, since the reflection only from the upper and lower light-insulating coating 29 (Fig. 15 c) takes place.

Claims (12)

Claims 1. Process for the production of light guides with a light-guiding Element that is surrounded by optically isolating elements, thereby g e k e n n z e i c h n e t that the manufacture of the light-guiding element by application a light-guiding layer in the manner of one of the predetermined light guide shape corresponding branched pattern takes place on the inner surface of at least one of layers, which serve as optically isolating elements. 2. The method according to claim 1, characterized in that at least in an optically insulating layer corresponding to the required light conductor shape Grooves are formed, which are then filled with a light-conducting substance. 3. The method according to claim 1, characterized in that light guide by mechanically pressing in at least two film layers (17, 18) one optically insulating and a light-conducting substance are produced with one tool, the surface of which has a relief corresponding to the predetermined shape of the light guide0 4. The method according to claim 1, characterized in that a separately produced, branched light guide system enclosed by optically insulating cover layers will. 5. The method according to claim 1, characterized in that inside an optically insulating material cavities with figure profiles are formed, which are then filled with a light-conducting material, 6. Procedure according to one of the preceding claims, characterized in that the applied light-conducting Material along the light guide or in its cross-section different optical Has properties. 7. The method according to claims 2 and 5, characterized in that that the layer consisting of light-conducting material is a film (25) which covers the groove surfaces of an optically isolating die0 8. The method according to claim 1, characterized in that a crystal layer is grown on a base by growing crystals is formed with a large refractive index, from which, in particular by etching, a branched light guide is formed, the surface of which is coated with an optically insulating Layer can be coated. 9. The method according to claims 1 and 8, characterized in that that the crystals constituting a light guide are grown in grooves which has been created in a document beforehand. 10. The method according to claim 1, characterized in that a light-conducting and photosensitive layer (27) through a predetermined pattern exposed and then developed and fixed, with unexposed areas a Form light guides with the desired shapes - by optically insulating layers (29) is limited. w light guide assembly manufactured by the method of a of claims 1 to 9, characterized in that a single light-conducting Layer of branched light guides formed with a figure profile inside an optically insulating material. 12. Light guide arrangement according to claim 11, characterized in that that in the material of an optically insulating coating electrodes and elements an electrical circuit are built in, which together with the light guide assembly Form optoelectronic devices. Blank page