DE3317057A1 - Photoelectronic sensing device - Google Patents

Abstract

The invention relates to a photoelectronic sensing device, in particular for rim edge scanning of a moving web 11 in a web motion control device, having at least one light source 5 and a receiver part 6 aligned with the light source 5 and having at least one light-focusing element which is connected to a photoelement arrangement generating signals as a function of the received quantity of light. In known sensing devices of this type, concave mirrors, lenses or similar devices are used to focus the received light. The technical outlay for constructing the receiver part is exceptionally high. Nevertheless, the response of the known sensing devices is unsatisfactory and, moreover, the useful sensing range is too small for various applications. According to the invention, these disadvantages are avoided when the light-focusing element is a member, which as receiving part 6 is made from a plastic which is dyed in a fluorescing fashion and has light-collecting properties (LISA plastic), and has at least one light-entry surface and at least one light-exit surface. <IMAGE>

Description

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The invention relates to a photoelectronic sensing device specified in the preamble of the claim!

Such sensing devices are used, for example, for scanning the edge of a running web in a web guiding system used to keep the track in a target track. As soon as the path begins to run, the edge more or less covers the sensing area and the amount of light that is emitted by the light source reaches the receiver part, reduced or increased. This change in the amount of light turns into photoelectronic Path signals derived with which a web run correction is adjusted. The light collected in the receiver part is e.g. through mirror arrangements, lenses or the like. A photo element arrangement, which is then responsible for generating the signal. The structural effort is extremely large here. Nevertheless, only relatively narrow sensing ranges can be achieved and an unsatisfactory response sensitivity is achieved for various purposes.

The invention is based on the technical problem of providing a photoelectronic sensing device of the type mentioned at the beginning create, which through a simple structure, a practically arbitrarily large sensing area and an extremely sensitive Excellent responsiveness.

The problem posed is solved according to the invention by the features specified in the characterizing part of the main claim.

Such bodies made of LISA plastic work with an extraordinarily high degree of efficiency, bundle the light received via the light entry surface in a very concentrated manner and convert it and emit it extremely evenly in the area of their light exit surface. LISA-Kunstsioff is practically unlimited Forms processable and commercially available. Thanks to the good

Verarheitharkeit this plastic material can be for such The body required for sensing devices can be designed in a very simple manner and easily incorporated into the receiver part. The light-gathering Properties of the LISA plastic are relatively permanent. The influence of extraneous light, light fluctuations or contamination is extremely low. LISA plastics are for example in leaflet KL kl310, 1.3.1981 from Bayer AG described in detail. These are fluorescently colored, light-collecting and light-conducting polymers of high quality optical purity. In it, the transparent plastic and a fluorescent dye form a system that is direct or diffuse Light is absorbed and emitted as fluorescence radiation in the plastic matrix. If the plastic is in sheet form, it will the absorbed light is transported by total reflection to the edge of the plate and released there. For this conversion is Light with wavelengths exceeding 370 nm can be used.

An expedient embodiment of the invention emerges from claim 2. In this training, the light passes through the entire sensing range. In contrast to a previous principle, the light is not directed to the photo element arrangement, but the photo element arrangement is so along the Arranged light exit surface, as this best corresponds to the respective purposes.

Another important idea is contained in claim 3. Just Red and thus long-wave light is of particular advantage in such sensing devices, as it is an influence of external light can be greatly reduced ^. Quite apart from this advantage, the task could also be solved with a different light color. It would only be the ones responsible for these wavelengths To use light receiving elements, so corresponding photodiodes.

An embodiment of the invention that is particularly suitable for practice

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finding is also evident from claim k. Such a one Plate is an inexpensive element or body that can be easily manufactured in the respective size The basic shape has a large light entry surface and a small one has a long light-emitting surface. Depending on which area of the light entry surface is exposed to the incidence of light, the photo elements arranged along the light exit surface are activated differently. The plate can also be composed of several individual pieces placed next to one another, whereby their effect and performance is not limited.

Another, expedient embodiment of a sensing device suitable for practical use emerges from claim 5. The too A tube-shaped plate or film has a relatively larger light entry surface than a flat plate. In addition, it is achieved in an advantageous manner that the two edges of the to one Place bent tube or sheet against each other and form a coherent light exit surface, so that the photo elements arranged there are or also acted upon very strongly can clearly register slight changes in the amount of light. The response behavior of the sensing device is correspondingly sensitive.

Since it is useful for a perfect control behavior when using the sensing device if a relatively linear signal output is achieved depending on the change in the amount of light, the embodiment of claim 6 is particularly advantageous, in which the sensing area has a finite width. The practice has shown that the photo elements can be lined up evenly in order to achieve a linear characteristic. The line becomes even straighter if the distances are chosen closer. The photo elements only need to be narrower at the ends of the light receiving and emitting plate than in the rest of the area can be set if the characteristic is to remain linear there too. But if there is enough space in the web edge area

then the plate can be chosen longer without including the ends in the sensing range. This is how you borrow certainly in the linear range. It is useful here to guide the material web at a sufficient distance over the light-absorbing body, because the characteristic curve remains linear.

Alternatively, the procedure according to claim 7 can also be used. Here, care is taken from the outset that, due to the narrower light entry surface in the central area of the sensing area, the photo elements arranged are less exposed, so that despite the same distances between the Photo elements ultimately produce a linear signal characteristic again.

A further, expedient embodiment of the invention emerges from claim 8. Since LISÄ plastic is easy to process using modern plastic processing techniques, the Body can be given virtually any shape. It is conceivable to design the body as an elongated wedge or as a wave-shaped profiled plate, in which the light entry surface is particularly large in relation to the light exit area. Such a molded part can be self-supporting and directly to Formation of the receiver part can be used in the sensing device without the need for supporting or holding devices would be. It is even possible to assemble the body from several parts that are simply put together flush are.

It has also proven to be advantageous if the features of claim 9 can be used. Such sprues could be short and slender and would not be a hindrance on the underside. These sprue pins would have to be provided in the number corresponding to the desired photo elements. Instead of the sprue pin you could bores are also made in the body, from which the photo elements received their light. At the ends of the sprues

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or from holes the collected one becomes particularly favorable Light removed.

Another important idea is contained in claim 10. In this way, the efficiency of the LISA plastic can be improved slightly, since it is absorbed from the Light is only emitted where fluorescent light can be tapped from the photo element arrangement.

Another important idea emerges from claim 11. Photodiodes connected in parallel, which are connected in parallel to a DC voltage supply, give in connection with the body made of LISA plastic emits a clear voltage signal, which reacts directly to even the smallest changes in the amount of light responds to fluctuations that can be tapped as control parameters. In addition, photo elements are inexpensive and commercially available components extremely small dimensions and long service life.

It is useful when proceeding according to claim 12. The circuit board with the photodiodes can be a prefabricated, inexpensive component.

Another, useful idea is implemented in an embodiment as emerges from claim 13, and in the an at least partially transparent receiver housing is provided. Glass or a transparent one is usually used for this Plastic used. A glass or plastic tube offers the desired optical properties, i.e. the lowest possible light losses on the way to the light entry surface of the LISA body and isj; also inexpensive and very solid. Particularly in the case of sensing devices for web guiding devices, a certain degree of robustness against soiling or scratching is required. A plastic pipe meets these requirements.

In an aforementioned embodiment, it is useful if

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is proceeded according to claim Ik. It's that way no additional holding devices for the body made of LISA plastic required, but this holds as a result of it Elasticity automatically in the plexiglass tube.

It is important, albeit the features, of claim 15 are given, since in this way the circuit board is attached to the LISA plastic body on the one hand and a clean passage of light from the light exit surface to the photo elements is guaranteed.

In an embodiment which has also been explained above, it can also be expedient to proceed according to claim 16 or 17, since then no additional holding devices are required to accommodate the plate in the Plexiglas tube. The inherent elasticity of the printed circuit board or the printed circuit boards themselves ensures that the plate is permanently seated in the transparent plastic tube. The circuit boards can be flexible and still be stable copper sheet strips, as neither the LISA plastic body nor the plastic pipe are electrically conductive.

Another useful idea is contained in claim 18. The influence of extraneous light can be largely eliminated with the grid, as it ensures that only parallel light beams are used meet the light entry surface.

Another embodiment of the invention which is suitable for practical use emerges from claim 19. This basic body, in which the individual active elements are housed, can be incorporated particularly easily into a web guiding device.

Finally, it has proven to be expedient to use either photocells, photodiodes, photoresistors or phototransistors for the photocell arrangement, depending on the intended use and purpose of the sensing device.

Embodiments of the invention are described below with reference to the drawings.

Show it

1 shows a schematic side view of a sensing device, FIG. 2 shows a section in the plane II-II in FIG. 1 2a shows a modified embodiment in a section corresponding to FIG. 2, Fig. 3 is a perspective view of part of a first

Embodiment, FIG. 4 is a perspective view of part of another embodiment,

FIG. 5 shows a plan view of a detail from FIG. 3, FIG. 6 shows a modified embodiment of the detail from FIG. 5, FIG. 7 shows an enlarged detail section from FIG. 3 Fig. 8 is a block diagram similar to the previous figures

is assigned and 9 shows a graph of the voltage modulation.

In Figures 1 and 2, a sensing device can be seen, such as it is preferably used for web guiding devices with which a running web is guided along a target track will. The sensing device scans the position of one edge of the material web and corrects immediately if the material web should only be aligned flush on one edge. A similar sensing device can be provided on the opposite edge. In that case the resultant of two signals of the sensing devices, the correction signal for the web guiding device when the web runs away to the side in its entire width. The web guiding device then exerts a force pulse to correct the web run until the sensing device detects again that the edge is running properly. The sensing device shown in Figs. 1 and 2 operates in a photo-electronic way, i.e. it is by a

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Light source a light curtain or a light band directed onto a receiver part, the web with its edge between the light source and the receiver part is running. Depending on the extent to which the web covers the receiver part in relation to the light source, the amount of light collected will cause a, e.g. An electrical signal is generated which informs the web guiding device how the web is running. Such web guiding devices are known and therefore do not need to be explained in detail.

In the embodiment shown, the sensing device has a fork-shaped base body 1 made up of a base part 2 and arms 3, h extending from it like prongs at an intermediate distance, of which the arm 3 contains a light source 5, while the other arm U has a receiver part 6 for the from Light source 5 contains emitted light, which passes on incident light L to a photo element arrangement that will be received later, but not shown in the figure. The base part 2 can be fixed with fastening elements 8 in such a way that a path 11, indicated by dashed lines, runs with its edge 11a between the two arms 3, 4 . With 9 and 10 supply connections and a signal output are indicated. In the arm h, a grid 7 can be arranged, which consists, for example, of partition walls 7a parallel to one another, and ensures that mainly parallel light components are guided to the receiving part 6. In this way, the influence of extraneous or scattered light can be largely eliminated.

In Fig. 2, the two arms 3 and h are shown as tubes. Fig. 2a indicates a variant in which the tubes 3a and Ua are designed as square hollow profiles.

3 shows, in an enlarged and perspective sectional illustration, a first embodiment of the arm k with a receiver part 6 of the sensing device of FIG. 1. In a glass or transparent plastic tube as the housing 21, which is not shown in FIG

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Orphan connected to the base part 2 is a thin plate 12 housed from a LISA plastic, which extends over the entire sensing range of the sensing device. The plate 12 has a first light inlet surface 13 on its upper side and a second light inlet surface Ik on its lower side, with only the light entry surface 13 is perpendicular to the incident light L opposite. The lower surface Ik is expedient covered, e.g. mirrored or blackened 15. The plate 12 has longitudinal edges 16 and 17 which serve as light exit surfaces. The / ordere end face 32 of the plate 12, which also represents a light exit surface, is expediently also mirrored. Applicable. On the longitudinal edge 17 of the plate 12, a strip-like circuit board 18 with retaining or guide pins 19 is attached in such a way that it rests directly on the longitudinal edge 17. Photo elements 20, e.g. photodiodes, are located in the circuit board 18 at certain intervals. arranged with their window either directly on the longitudinal edge

17 or at least directly opposite it.

The 3reite of the plate 12 is slightly narrower than the inner diameter of the housing 21, which is designed as a glass or plastic tube. The circuit board 18 is resilient and is used Secure the plate 12 in the housing 21 in position. Namely by the plate 12 with its longitudinal edge 16 on the inside of the housing 21 is supported on the one hand, while the circuit board 18 is with its two longitudinal edges with a slight bend on the other Inside of the housing 21 is supported.

In itself it is sufficient to have a printed circuit board only on the longitudinal edge 17

18 to be arranged with photo elements 20. However, it is also conceivable a correspondingly designed printed circuit board 18a (indicated by dashed lines) to be attached to the other longitudinal edge 16 of the plate 12 and also to be equipped with photo elements 20.

The plate 12 consists of a light-collecting (LISA) plastic. Such plastics are fluorescently colored, light-collecting and light-conducting polymers of high optical purity. The-

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This polymer absorbs direct or diffuse light from the environment, which it absorbs via the light entry surfaces. In the Plastic matrix, this light is emitted as fluorescent radiation by being transported to the light exit surface by total reflection and emitted there. For such a conversion of light, light of wavelengths greater than 370 nm is required suitable. The light intensity in the light exit surface is dependent on the geometric dimensions of the plate 12 Reinforced from LISA plastic.

The photodiodes 20 accommodated on the circuit board 18 are expediently connected in parallel and connected to a DC voltage supply on the one hand and a signal output line on the other. For this purpose, corresponding conductor tracks are provided on the circuit board 18 (not shown). When exposed to light, the photodiodes 20 change the voltage, which can be tapped as a signal value. Depending on how much is covered by the web 11 from the light entry surface 13 of the plate 12, a voltage value lying between a minimum and a maximum value is emitted, which indicates to the web guiding device where the edge 11a is located exactly. Since the LISA plastic of the plate 12 has the property To change the intensity of the emitted light axakt as a function of the amount of light that enters the light entry surface, a very sensitive signal output can be achieved. As Indicated by dashed lines, one or more sprue pins 16a can sit distributed on the underside lh of the plate 12 and out of their Ends emit the collected light to the photo elements 20. Instead of the sprue pins 16, drilled holes 16b could also serve as a light exit surface.

FIG. H illustrates a further embodiment of a receiver part 1 + 'which can be used for the sensing device according to FIG. 1 is. In this embodiment, in the tubular housing 21, which is covered, for example, on the underside in an opaque manner, or

consists of a normal hollow profile with a Hchtightproof insert 31, a tube 23 is arranged, which in turn consists of a LISA plastic is made. In this case the LISA plastic is used formed into a thin plate 22 or film with a certain width, this plate 22 then forming the closed tube 23 is bent and the edge regions 25a, 25b are bent inward so that their free longitudinal edges 26, 27 can be located lie next to each other and form a continuous and even light exit surface. The tube 23 can be covered or mirrored on the end face 2k so that no light is lost here. Practically the entire outer circumference and inner circumference of the tube 23 forms the light entry surface, while the adjacent free longitudinal edges 26, 27 represent the light exit surface. Mainly, however, the upper area of the pipe circumference up to the height of the center of the pipe is used for the incident light L Light entry surface used. In order to avoid the influence of scattered or extraneous light, they could not allow the direct entry of light used surface areas of the tube 23 can also be mirrored or covered, which further improves the efficiency lets practice there? ' no light can be lost in the inner or outer peripheral surface areas.

The two edge regions 25a, 25b are held together with a U-shaped clip profile 28 on which a printed circuit board 29 sits. In the circuit board 29, photo elements 20 are arranged in such a way that their windows are aligned with the longitudinal edges or light exit surfaces 26, 27. When the bracket profile 28 goes through the length, it is necessary to provide recesses 30 at least in the area of the photo elements 20.

FIG. 5 shows a plan view of the plate 12 with the printed circuit board 18 and the photodiodes 20 from FIG. For a web guiding device, an almost linear voltage modulation by the photodiodes 20 is desirable if, for example, the web edge

edge 11a from a position in which the plate 12 is completely with respect to the light source 5, which is preferably a fluorescent tube, covers, migrates into a position in which the plate 12 is completely exposed to the incident light. As a result of the light-collecting properties of the LISA plastic on the one hand and As a result of the modulation behavior of the photodiodes, on the other hand, an S-shaped, curved course of the voltage modulation will occur in the case of a light entry surface with a constant width over the entire length, which is not desired for the purpose of web guiding. This effect can now be done in a simpler way Way are compensated by the fact that at the respective end of the sensing range between the photodiodes 20 different and tighter distances can be chosen. In Fig. 5 it can be seen that only at the two ends of the sensing area M the Intermediate distances dl, d2, d3, dif, etc. between the photodiodes become closer and have a constant distance from one another in the rest of the sensing range. With this arrangement, a largely linear voltage modulation is achieved, as shown in FIG. 9 in the diagram is shown. The points on the length of the plate are plotted graphically in relation to the voltage prevailing there.

This is illustrated by an example:

With a sensing area M with a length of UOO mm and a Distance between the light collecting plate and the fluorescent source of 200 mm, the length of the measuring area, e.g., in 37, becomes the same large sections of length divided. The photodiodes are now arranged in the circuit board 18 so that along the plate 12 only in the length sections 1, 2, h, 7, 11, 15, 19, 23, 27, 31, 3h, 36 and 37 photodiodes sit. With this arrangement an almost linear voltage modulation is achieved over the sensing range, with a DC voltage supply of 20 volts, the diodes have their signal output voltage of approximately 17 volts when not modulate the covered sensing area to approximately 3 volts with a fully covered sensing area.

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The fluorescent tube has a nominal output of 8 watts at 220 volts AC voltage.

A linear signal voltage curve can also be achieved in other ways, e.g. by partially covering the light entry surface with photodiodes arranged at the same distance or, as shown in FIG M has a significantly smaller width b than the width b ₁ at both ends of the sensing area M. In the case of a plate 12 'designed in this way, the photodiodes 20 can be arranged in the circuit board 18 at equal distances d from one another.

7 shows in detail the connection of the plate 12 to the printed circuit board 18. The underside of the plate 12 is covered at 15. The light exit surface in the area of the longitudinal wall 17 rests on the printed circuit board 18 in which the guide pins 19 are embedded are so that the circuit board 8 on the plate 12 are fixed can. The photodiode is located in an opening 33 of the circuit board IB 20 housed so that its window of the light exit surface is directly opposite or even rests against it. On the circuit board 18 conductor tracks 3k, 35 are provided, with which the photodiode 20 is connected with their contact legs 36,37.

Finally, FIG. 8 shows a schematic block diagram in which the photodiodes 20 are arranged parallel to one another and from a DC voltage supply source 38 via the conductor track 3k voltage can be applied. The photodiodes 20 are connected to an amplifier 39 via the conductor 35 and are connected are at the same time biased against ground by a relatively low resistance kO. The amplifier 39 is in A signal value is emitted as a function of the exposure to light of the photodiodes 20. This signal value changes depending on how much each photodiode 20 or how many photodiodes 20 are involved the same light intensity can be applied.

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Instead of the photodiodes 20, which require a DC voltage supply to work, photocells could also be used which do not require an external energy supply. Would be conceivable Furthermore, instead of the photodiodes 20, photoresistors or phototransistors can be used.

The embodiments described above represent only a selection from many possibilities. The. LISA plastic can Using modern processing techniques, bring them into the desired shape for the respective purpose. Instead of a plate or a film, molded parts could therefore also be injection-molded are produced, which are enlarged via a corresponding light entry surface, e.g. by corrugation or structuring, and a appropriately oriented, concentrated light exit surface, e.g. one or more sprue cones. The embodiments 3 and h are structurally particularly simple, inexpensive solutions. The glass or plastic tube has one in both cases Protective function. If the light-collecting plastic is blocked to form a self-supporting molded part, the tube could also be omitted. Furthermore, it would be conceivable to use the photo elements directly in to embed the light exit surface and also to provide the conductor tracks for the photo elements there. The printed circuit boards used can be of conventional design, i.e. made of insulating plastic with. be vapor-deposited or printed conductor tracks. A copper strip would also be conceivable for this purpose. Another possibility in Fig. 3 would be that in the plate 12 lying one behind the other in the longitudinal direction and with the respective intermediate distances bores are made in the plate, in which then the photodiodes are inserted. In such bores, too, the captured light is amplified and emitted in a concentrated manner.

The special advantage of the light-collecting plastic for this The purpose of use is not only simple processing and inexpensive procurement, but also the sensitive control behavior.

ten, which can be achieved in this way and an extraordinarily broad feeling range, as it could hardly be achieved before.

Claims (1)

Applicant: Erhardt & Leimer GmbH, Augsburg Photoelectronic sensing device Claims 1. Photoelectronic sensing device, in particular for scanning the edge of a running web in a web running control device, with at least one light source illuminating the sensing area and a receiver part oriented towards the light source, and with at least one light-bundling element arranged in the receiver part, which is connected to at least one in Depending on the amount of light received, the photo element arrangement is connected to generate signals, characterized in that the receiver part (6) is a body made of a fluorescent colored plastic with light-collecting properties (LISA plastic) and at least one light entry surface (13) and at least one light exit surface (17 , 26, 27), 2. Feeling device according to claim 1, characterized in that the body extends in the receiver part at least over the sensing area (M) and at least with part of its light entry Bank accounts: Deutsche Bank Ingolstadt 23/51310 BLZ 72170007 Postal checking account Munich 225940-800 BLZ 70010080 surface (13) on the light source (5) and with at least one light exit surface (17, 26, 27) on the photo element arrangement (20) is aligned. 3. sensing device according to claims 1 and 2, characterized in that the plastic for generating a light of wavelength vorbestimnter is colored and preferably colored red. If. Feeling device according to claims 1 to 3, characterized in that the body is an elongated plate (12) made of LISA plastic, the upper light entry surface (13) of which is aligned perpendicular to the light source (5), and that a plurality of along at least a longitudinal edge (17) of the plate (12) with spacings (dl, d2; d) arranged photo elements (20) are present. 5. Feeling device according to claims 1 to 3, characterized in that the body consists of a rectangular plate or film (22) made of LISA plastic and bent into a closed tube (23), the opposite edge regions (25a, 25b) of which are on the tube (23) are bent inwards or outwards and placed against one another in such a way that a continuous, flat light exit surface (26, 27) with a width corresponding to twice the plate or film thickness results, on which the photo elements (20) are arranged. 6. Sensing device according to claims 1 to 5, wherein the sensing area has a finite width, characterized in that the distances (dl to dn) between the photo elements (20) over the essential sensing area (M) are the same for generating a straight line characteristic of sensing pulses and are only set closer at the ends of the plate (12). 7. sensing device according to claim U, characterized in that at the same distances (d) of the photo elements (20) from one another over the entire plate (12 ') the light entry surface (13' J the Plate (12 ') is made wider at the ends. 8. Feeling device according to claims 1 to 3, characterized by an elongated and a large light entry area in relation to a small light exit area having molded part, for example an injection molded part, made of LISA plastic, 9. Feeling device according to at least eingm of the preceding claims, characterized in that the light-bundling body (12, 23) has one or more sprue pins (16a) evenly distributed over the sensing area (M), at the ends of which the photo elements (20) sit. 10. Feeling device according to at least one of the preceding claims, characterized in that the areas of the light-bundling body (12, 23) facing away from the light source and not facing the photo-element arrangement are covered, for example mirrored. 11. Feeling device according to at least one of claims 1 to 10, characterized in that the photo elements (20) are photodiodes connected in parallel. 12. Sensing device according to claim 11, characterized in that the photodiodes are arranged on a circuit board (18, 29) which is attached to the body (12, 23). 13. Feeling device according to at least one of claims 1 to 12, wherein an at least partially transparent receiver housing is provided, characterized in that the housing (21) is a glass or transparent plastic round or square hollow profile, in which the body (12, 23 ) is secured in position. Ik. Feeling device according to claims 6 and 13, characterized in that the body (23) constructed as a tube with a nem light press fit is fixed in the housing (21), the bent longitudinal edges (26, 27) are fixed by a clamp device (28) which is structurally integrated in the printed circuit board (29). 15. Feeling device according to claims 12 and Ik, characterized in that on the circuit board (18, 29) a U-shaped bracket profile, several U-shaped brackets or with the thickness of the plate (12) or the two plate or guide pins (19) spaced apart from the longitudinal edges (26, 27) of the film are provided. 16. Feeling device according to at least one of the preceding claims, characterized in that the width of the plate (12) made of LISA plastic is slightly smaller than the inner diameter of the housing (21), and that with the plate (12) on a longitudinal edge connected circuit board (18) is designed to be flexible, such that the plate (12) is secured in position in the housing (21) by means of the bent circuit board (18). 17. Feeling device according to claim 16, dadurc h gekennz eichnet that a circuit board (18, 18a) with photodiodes (20) is attached to both longitudinal edges of the plate (12) and that the plate (12) by means of the circuit board. (18, 18a) can be secured in position in the housing (21). 18. sensing device according to claim 13, characterized in that irr. Housing (21) above the light entry surface (13) of the body (12) a grid (7) of preferably parallel partition walls (7a) aligned perpendicularly to the light-intrittsfUiche (13) is arranged. 19. Feeling device according to the preceding claims, characterized by a fork-like base body (1), in one of the fork prongs (3) the light source (5) is arranged and the other fork prong (U) of the housing (21) forming the receiver part (6) with the body hidden in it (12, 23) is formed, in which the prongs (3, U) connecting the base part (2) of the base body (1) power supply components, Control devices and signal-emitting or signal-transmitting circuit parts (9, 10) are housed. 20. Feeling device according to the preceding claims, characterized by the use of photo cells, photo diodes, photo resistors, photo transistors for the photo element arrangement.