EP2929330A2

EP2929330A2 - Detection of a periodic structure in a moving elongated textile material

Info

Publication number: EP2929330A2
Application number: EP13802857.6A
Authority: EP
Inventors: Rafael Storz; Peter Pirani
Original assignee: Uster Technologies AG
Current assignee: Uster Technologies AG
Priority date: 2012-12-10
Filing date: 2013-12-02
Publication date: 2015-10-14
Also published as: WO2014089714A2; WO2014089714A3; JP2016500439A; CN105308440A; US20150308036A1

Abstract

In a method for detecting a periodic structure in a moving elongated textile material (9), said textile material (9) is sampled simultaneously at multiple detection points (43.1-43.5) located equidistantly in the longitudinal direction (91) of said material. Sampling signals that can be detected at the detection points (43.1-43.5) are added to form a composite signal. Temporal changes in the composite signal are indicative of a periodic structure in the textile material (9). A localised spectrum of the structure of the textile material (9) can be obtained with multiple groups of multiple equidistant detection points (43.1-43.5) with practically no computational effort.

Description

RECOGNITION OF A PERIODIC STRUCTURE IN ONE MOVE

LONG TEXTILE MATERIAL

AREA OF EXPERTISE

The present invention is in the field of textile material testing. It relates to a method and a device for detecting a periodic structure in a moving elongated textile material, according to the preambles of the independent

Claims. The invention can be used, for example, in yarn testing machines in textile laboratories or in yarn cleaners on spinning or winding machines.

STATE OF THE ART

A variety of different methods and devices for testing textile materials are known. In the textile testing devices come various

Sensor principles for use. The present invention uses the optical sensor principle, the z. B. from WO-2004/044579 AI is known. The textile material is illuminated by a light source and light interacting with the textile material is detected by light detectors. The detected light is a measure of the diameter of the textile material and / or its optical properties such as reflectivity or color.

Some prior art devices use optoelectronic

Sensor lines to a shadow through the textile material

Measure transverse dimension of the textile material. The sensor lines themselves are usually implemented in CMOS or CCD technology and are available on the market. Examples of such optical textile measuring devices are in the specifications CH-643'060 A5,

EP-0'971'204 A2 and WO-99/36746 Al.

From WO-89/01147 AI a method and an apparatus for error detection in moving fabrics are known. A rectangle is illuminated on the fabric and imaged by anamorphic image onto a line or matrix sensor. In this case, the light coming from a certain range in the direction of movement of the substance is optically integrated. In the integration signal, defects in the substance are more pronounced and can thus be better recognized. In order to detect periodic yarn defects, usually a time-dependent

Output signal of a yarn sensor by means of Fourier transformation in the

Time frequency space transformed. The frequencies represented in the time-frequency domain with large amplitudes indicate periodic yarn faults, while the amplitudes of the remaining frequencies are a measure of the aperiodic yarn uniformity.

Examples of methods which use the Fourier transform are given in US-2,950,435 A, US-5,592,849 A and EP-2'090'538 A2. The calculation of the Fourier transformation is complex, regardless of whether it is analog or digital.

EP-1'553O37 AI discloses a device for measuring speed on a running yarn. The device has a plurality of equidistantly arranged in the direction of the yarn light receiver. The yarn is illuminated in transmission so that its shadow falls on the light receivers. In the yarn inherent irregularities such as protruding fibers generate time-varying signals in the light receivers. The signals of the individual light receivers are added to form a sum signal. The yarn speed results from the multiplication of the sum signal

predominant time frequency with the equidistance of the light receiver.

In DE-36'28'654 C2, a method for determining the length inequality of the single yarn components of a running yarn is described. The twisting structure is optically scanned transversely to the direction of movement. The scanning signal becomes one

Subjected to frequency analysis. If all single yarns constituting the twist have the same length, the scanning signal contains a single frequency component with a certain fundamental frequency. In the case of single yarns of different lengths, on the other hand, subharmonics of the fundamental frequency occur in the scanning signal.

Printed circuit boards with optical waveguide structures and electrical conductor structures are known per se, for example from US-2010/0209854 AI. PRESENTATION OF THE INVENTION

It is an object of the present invention to provide a method and apparatus for detecting a periodic structure in a moving elongate textile material, by means of which the periodic structure is easier and faster to recognize than in the prior art. The periodic structure should also be quantifiable if possible.

These and other objects are achieved by the method according to the invention and the device according to the invention, as defined in the independent patent claims. Advantageous embodiments are given in the dependent claims.

The theoretical background of the invention is the system theory for linear systems. The invention is based on the idea that the textile material at several along its

Sense longitudinally equidistantly arranged discrete detection sites and from a sum signal of the detection points on a periodic structure of the

Close textile material. If several such groups of detection sites with different equidistances are provided, then the

Sum signals a local spectrum of the structure of the textile material can be obtained. In other words, thanks to the invention, a Fourier transformation of the structure of the textile material can be produced virtually without any computational effort.

The detection points are those points where the textile material is scanned directly. They are as close as possible to the textile material or at his

provided path to achieve a high signal-to-noise ratio and high spatial resolution. The distance between the textile material and a detection point is preferably between 0.1 mm and a few millimeters. Attached to the detection points are elements intended to receive physical signals bearing information about the textile material. The physical signals can z. B. transmitted by electromagnetic fields. In a preferred embodiment, ends of optical waveguides are located at the detection points, and measuring electrodes in another embodiment. A particularly suitable technology for the practice of the invention is an optical waveguide structure integrated on a substrate. First, it allows a dense linear array of many discrete detection sites in a scan area. The smallest equidistance of the detection sites should be at most as large as the smallest spatial period to be detected in the textile material, and the length of the scanning region should be at least as large as the largest detecting spatial period. With integrated optical waveguide structures, submicron immersion distances over several centimeters are possible. This covers an interesting range of local periods to be expected in common textile materials such as yarns. Secondly, waveguide branches can be realized with the integrated-optical waveguide structure, by means of which the light components detected at a plurality of detection sites can be brought together so that an optical sum signal results after the merging. By terms such as "optical sum signal" or "addition of light components" is meant in the present document the sum or addition of the individual light intensities.

In the inventive method for detecting a periodic structure in a moving elongate textile material, therefore, the textile material is simultaneously scanned at a plurality of discrete, arranged along its longitudinal direction and equidistantly spaced detection sites, detected at the detection points

Scanning signals are added to a sum signal, and due to temporal changes of the sum signal is concluded that a periodic structure of the textile material. In a preferred embodiment, multiple groups of each of a plurality of discrete detection sites are provided, wherein the detection sites within each group are equidistant and the aquidistances of the different groups are different. In each group, the detected scanning signals are added to a sum signal, and due to temporal changes of the individual

Summed signals are compared periodic components in the structure of the textile material. It is advantageous to automatically display values of a variable corresponding to the temporal changes for the several groups in a diagram. In the diagram, preferably, each value is given the equidistance of group concerned and / or with a spatial frequency which essentially corresponds to the reciprocal of the Aquidistanz called. The number of groups is, for example, between 2 and 50, preferably between 5 and 20. The number of detection sites is, for example, between 5 and 500, preferably between 20 and 200.

All detection points can lie on an equidistant grid. The Aquidistanz the grid is, for example, between 0.1 mm and 10 mm.

In a preferred embodiment, the scanning is carried out optically at the detection sites. In this case, the sum signal may be a sum of intensities of light components detected at the detection sites. The intensities can by means of

Merging of optical fibers are summed.

A speed of the textile material s can be determined by in the

Sum signal a predominant frequency is determined and the speed is calculated as the product of the time frequency and the Aquidistanz the detection points. The device according to the invention for detecting a periodic structure in a moving elongate textile material comprises a substrate having a plurality of discrete detection points arranged along the longitudinal direction of the textile material and equidistantly spaced from each other for the simultaneous optical scanning of the

Textile material. On the substrate is an optical waveguide structure for

Merging merged at the detection points Lichtanteilen and for guiding the merged light components to a decoupling interface, which is designed for coupling out of light from the waveguide structure, integrated.

An optical waveguide structure integrated on a substrate is understood in this document to mean a waveguide structure which is monolithically housed in or on the substrate. The waveguide structure was originally produced on the substrate, for example by technologies such as photolithography and / or doping - in contrast to

discrete, discrete waveguides which are subsequently applied to a substrate were. The integrated optical waveguide structure is inseparably connected to the substrate. It includes a plurality of transparent dielectric layers with different refractive indices. Preferably, a core layer with a higher refractive index is embedded between a lower layer and an upper layer with lower refractive indices, so that light waves can be conducted in the core layer. The waveguide structure can be strip waveguides that conduct light in one direction and / or planar

Thin-film conductors in which light can propagate in two directions include. In addition to the waveguides, they may include other passive and / or active integrated-optical components such as lenses, beam splitters, reflectors, filters, amplifiers, light sources and / or light receivers.

The optical waveguide structure is preferably formed such that in

Merging a sum of intensities of the light components detected at the detection points formed and the sum signal thus formed is guided to the decoupling interface.

The optical waveguide structure may have at least one branch with at least two branches. In addition, the optical waveguide structure may include at least one waveguide for guiding light to the detection sites.

The detection sites are preferably provided with at least one converging lens.

The decoupling interface can be designed to connect the waveguide structure to an optical connector. It is advantageous if the

Decoupling interface is attached to an edge of the substrate.

In a preferred embodiment, several groups of a plurality of discrete detection sites are arranged on the substrate. The detection sites are within each group equidistant, the equidi punching of the various

Groups are different. The optical waveguide structure is for combining light portions detected in each group and guiding the individual ones merged light components formed to a decoupling interface. The number of groups is, for example, between 2 and 50, preferably between 5 and 20.

In the present specification, terms such as "light" or "illuminate" are used not only for visible light but also for electromagnetic radiation from the adjacent spectral ranges ultraviolet (UV) and infrared (IR).

TITLE OF DRAWINGS

The invention will be explained in detail with reference to the schematic drawings. The explanation will be made on the basis of the preferred example of the optical one

scanning; However, other scanning principles can also be used in the method according to the invention.

Figures 1 and 2 show schematically two different embodiments of a device according to the invention in plan views.

FIG. 3 shows schematically an arrangement of detection waveguides

Further embodiment of the device according to the invention a supervision.

FIG. 4 schematically shows two possibilities for the arrangement of

D etektionsstellen.

FIG. 5 schematically shows two different textile materials in FIG

Page views.

FIG. 6 shows (a), (b) possible time profiles of output signals of a

And (c) the output of Figure 6 (b) after rectification.

FIG. 7 shows a local spectrum obtained according to the invention

Textile material.

FIG. 8 schematically shows one end of an optical waveguide, one to

testing textile material and light rays in between in a plan view.

FIG. 9 shows schematically a further embodiment of a

Inventive device in a perspective view. EMBODIMENT OF THE INVENTION

FIG. 1 shows a first embodiment of a device 1 according to the invention. The device 1 serves to test an elongated textile material 9, for example a yarn, which is moved past the device 1 or past the device 1. The

Direction of movement of the textile material 9 coincides with a longitudinal axis of the textile material 9 and is indicated in Figure 1 an arrow 91. The device 1 comprises a substrate 2 on which a scanning region 3 for optically scanning the textile material 9 is provided. The substrate 2 may consist of a known material such as glass, a plastic, a semiconductor material or impregnated with epoxy glass fiber mat. It is preferably flat and rigid, d. H. practically does not deform. The longitudinal axis and direction 91 of the textile material 9 lies in the plane of the substrate 2, but outside the substrate 2. The scanning region 3 coincides with a part of one side of the rectangular substrate 2, is straight and parallel to

Longitudinal axis 91 of the textile material 9 is arranged.

In the scanning region 3, a plurality of discrete detection points 43.1-43.5 arranged equidistantly along the longitudinal direction 91 of the textile material 9 are disposed in the immediate vicinity of the textile material 9 or its path for optical scanning of the textile material 9. At each detection point 43.1-43.5, light that interacts with the textile material, for example, is reflected or scattered on it, is detected simultaneously. The number of detection sites is, for example, between 5 and 500, preferably between 20 and 200. On the substrate 2 is an optical waveguide structure 4 for together drove detected at the detection sites 43.1 -43.5 light components and for the management of

merged light components to a decoupling interface 51 integrated. in the

Embodiment of Figure 1 includes the waveguide structure 4 nine optical strip waveguides 41 .1 -41.5, 42.1-42.4. The waveguide structure 4 may, for. B. be made of a polymer that is sufficiently permeable to the wavelength of light used. It is preferably applied to the substrate 2 by a process that is illustrative. The transverse dimensions (width and height) of a single waveguide 41. 1 - 41 .5, 42. 1 -42.4 can eg. B. between 5 μιη and 500 μιη, preferably about 50 μιη, be. The Wellenleitersiraktur 4 may be located on an outermost layer of the substrate 2 or form an inner layer which is covered by at least one overlying layer. In the latter case, the layer above can

Waveguide structure 4 from mechanical damage, pollution and

Protect against unwanted optical influences. The waveguides 41.1 -41.5, 42.1 -42.4 can be embodied as a single-mode waveguide or as a multimode waveguide.

The waveguide structure 4 of Figure 1 has a plurality of intersections of waveguides 41 .1 - 41.5, 42.1 -42.4. Care should be taken to avoid crosstalk from one waveguide to another at these intersections. The person skilled in the art of integrated optics is able to design the waveguide structure 4 in such a way that this condition is well met. This may be the case in particular if the respective crossing angle is close to 90 ° or at least not too acute. In addition, the waveguide turret 4 of FIG. 1 has branches, for example Y-branches. The branches can be designed as per se known Verzweigerbauteile. It may, as in the example of Figure 1, by 1 x 2 branches or

Higher order branches act. In addition to the waveguides themselves, the

Intersections and branches may include the optical waveguide structure 4 further integrated-optical components. These can be passive and / or active. Examples of such integrated-optical components are lenses, beam splitters, reflectors, filters,

Amplifiers, light sources and light receivers. In addition, optical elements such as light sources and / or light receivers can be applied to the substrate 2 as discrete, discrete components. At the mouths of the waveguides 41.1 -41.5, 42.1 -42.4 in the scanning region 3, preferably lying on a straight line, light-collecting elements 44 may be mounted as converging lenses to ensure the highest possible light output. As is known, light emerging from the end of a thin waveguide is radiated at a large aperture angle: in time reversal, therefore, light from the same large aperture angle is also coupled into the waveguide. Since the textile material to be tested 9 usually has a small diameter of less than 1 mm, it would be taken without countermeasures of only a small part of the available light, and of this in turn would only a small part back in coupled to a waveguide. The converging lenses 44 serve to avoid such light losses. Their function and structure will be explained in more detail with reference to FIG. Four of the nine waveguides 41.1-41.5, 42.1 -42.4, the following as

"Lighting waveguides" 42.1-42.4 are used to illuminate the textile material 9. For this purpose, they receive light from a transmitter module 62 and direct it into the scanning region 3, where it exits the illumination waveguides 42.1-42.4 and at least partially on the textile material 9. The transmitter module 62 may be attached to the end of a second electrical line 72. The light transfer from the transmitter module 62 into the illumination waveguides 42.1-42.4 takes place at a

Einkoppelschnittstelle 52, which is attached to an edge of the substrate 2. The

Einkoppelschnittstelle 52 may, for. B. be designed as a connector. The

Transmitter module 62 includes, for example, in a row juxtaposed light sources 64.1, 64.2. The light sources 64 may, for. B. be designed as a diode laser or as light emitting diodes. The coupling of the light from the light sources 64.1, 64.2 in the illumination waveguide 42.1-42.4 can by directly illuminating the

End of the illumination waveguide or by means of optical elements such as converging lenses 44. In the latter case, similar lenses can be used as at the mouth to the scanning region 3. However, it is advantageous if that from a

Illuminating waveguide 42.1-42.4 light is not focused on a small point on the fabric 9, but a longer portion of the textile material 9 illuminated. To ensure an effective coupling of the light in the

Illumination waveguide 42.1-42.4 at the coupling interface 52, it is important that the light sources 64.1. 64.2 be positioned as e akt and stable as possible with respect to the illumination waveguide ends. For this purpose, mechanical positioning means 53 for positioning the transmitter module 62 with respect to the substrate 2 are attached to the coupling interface 51. The positioning means 53 may, for. B. be designed as a suitable guides that provide accurate positioning within the connector. They are, as well as the other elements, indicated in Figure 1 only schematically.

The remaining five of the nine waveguides 41.1-41.5, 42.1 -42.4 serve to detect the light reflected from the textile material 9 and are therefore referred to below as "Detection Waveguide" 41.1 -41.5 designates the light that is transmitted by the

Detection parts 43.1-43.5 comes to a receiver module 61, which may be attached to the end of a first electrical line 71. The light transfer from the

Detection waveguides 41.1-41.5 in the receiver module 61 takes place at a

Decoupling interface 51, which is attached to an edge of the substrate 2. The

Auskoppelschnittstelle 51 can also be used as a plug connection with corresponding

Positioning 53 be configured. The receiver module 61 includes, for example, in a row juxtaposed light receiver 63.1, 63.2, each of which is assigned to a group of detection waveguides 41.1-41.5. The light receiver series can z. B. be designed as a CCD array. It would also be possible to combine a plurality of adjacent reception elements, which then form a "composite light receiver." With regard to the light extraction and the positioning and design of the coupling-out interface 51, what has been said about the coupling interface 52 applies analogously.

The branches in the waveguide structure 4 serve to be of a single

Light source 64.1 divide emitted light and multiple illumination waveguides

41.2, 41.4 supply and merge guided by a plurality of detection waveguides 41.1-41.5 light and supply a single light receiver 63.1. Especially the latter function, the addition of multiple scanning signals, is important to the present invention. Thanks to it, namely, several groups of a plurality of discrete detection parts 43.1-43.5 can be formed, wherein the detection parts 43.1- 43.5 within each group are equidistant and the equidistance of the

Different groups are different. In each group, the detected scanning signals are added to a sum signal and. due to temporal changes of the individual summation signals, periodic contributions in the structure of the

Textile material 9 compared to each other. In the embodiment of FIG. 1, all the detection parts 43.1-43.5 form a first group. The light components detected at the detection parts 43.1-43.5 of the first group are added to a sum signal in the detection waveguides 41.1-41.5 and supplied to the first light receiver 63.1. On the other hand, light is supplied to a second light receiver 63.2;

Detection point 43.1, 43.3, 43.5 detected, from each second detection waveguide 41.1,

41 .3, 41.5 out and added later. The last mentioned detection parts ,,,,

43.1, 43.3, 43.5 form a second group whose equidistance is twice that of the first group.

The receiver od u 1 61 and the transmitter module 62 are connected via the first electrical line 71 and the second electrical line 72 to an electronic unit 70. On the one hand, this controls the transmitter module 62. On the other hand, the electronic unit 70 receives signals from the receiver module 61, evaluates them themselves or forwards them, possibly after preprocessing, to an evaluation unit (not shown). It is advantageous to optically and mechanically precisely define the coupling-out interface 51 and the coupling-in interface 52 and thus to standardize it as it were. Then, the receiving module 61 and the transmitter module 62 with their relatively expensive optoelectronic components can be used without changes for different substrates 2. On the other hand, the relatively inexpensive substrates 2 with their integrated optical

Waveguide structures 4 are replaced as needed. A need for

Replacement of a substrate 2 can, for. B. arise when another

Waveguide structure 4 - especially when scanning 3 - is needed or if a substrate 2 is damaged by wear or otherwise defective. The erfmdungsgemässe device 1 is preferably housed in a housing, as it is known, for example, from US 5,768,938 A. For clarity, such a housing was not shown in the accompanying drawings.

FIG. 2 shows a second embodiment of the device 1 according to the invention. This is simplified compared to the first embodiment of FIG. 1 in the sense that two waveguide ends facing the scanning region 3 serve both for illumination and for detection. The corresponding converging lenses 44 must be designed as a compromise so that the illumination light illuminates as long as possible a portion of the textile material 9 and the detection light of as short as possible

Section of the textile material 9 comes. The branches are designed so that a large part of the light emitted by the light source 64 is emitted into the scanning region 3, and that a large part of the light received by the scanning region 3 is supplied to the light receivers 63.1, 63.2. The expert in the field of integrated optics is able to produce such branches with knowledge of the invention. In addition, only a single optical interface 55 is present, which serves both as Einkoppel- as well as decoupling interface. In the corresponding transmitter and receiver module 65 are thus both two light receivers 63.1, 63.2 and a light source 64th

FIG. 3 shows a third embodiment of the device 1 according to the invention, wherein, for the sake of simplicity, only a few important optical elements, namely the

Detection points 43.1-43.7 with the converging lenses 44, the detection waveguide 41.1-41.7 of the waveguide structure 4 and the light receiver 63.1 -63.3 at the decoupling interface 51, are shown. Other elements such as illumination waveguide, substrate, transmitter and receiver module, etc., can be configured analogously as in Figures 1 and 2 or otherwise. The embodiment of Figure 3 has z. B. three light receiver 63.1 - 63.3. The waveguide structure 4 with its branches is designed such that the following functions are realized:

• A first light receiver 63.1 is supplied with the sum of light components detected at all detection points 43.1-43.7. These detection sites 43.1-43.7 form a first group.

• A second light receiver 63.2 becomes the sum of every second

Detection point 43.1, 43.3, 43.5, 43.7 supplied detected light components.

These detection sites 43.1, 43.3, 43.5, 43.7 form a second group.

• A third light receiver 63.3 becomes the sum of every third

Detection point 43.1, 43.4, 43.7 supplied detected light components. These detection sites 43.1, 43.4, 43.7 form a third group.

The number of only seven detection points 43.1 -43.7 and only three light receivers

63.1-63.3 is small and has been chosen in Figure 3 only for the sake of clarity. In practice, one will choose a higher number of detection sites and a higher number of light receivers and structure the waveguide 4 accordingly. The number of detection sites is, for example, between 5 and 500, preferably between 20 and 200, and the number of light receivers is, for example, between 2 and 50, preferably between 5 and 20. In any event, Figure 3 illustrates an important aspect of the invention: several groups of a plurality of discrete detection sites are provided, the detection sites within each cluster being equidistant and the aquidistances of the different groups being different. In each group, the detected scanning signals are added to a sum signal. Due to changes over time of the individual sum signals, periodic components in the structure of the textile material 9 (see FIGS. 1 and 2) can be compared with one another. The receivers 63.1-63.3 output signals from which a spatial frequency spectrum of the structure of the textile material can be determined in a simple manner. If a is the constant distance (equidistance) of two detection points 43.1, 43.2 along the longitudinal axis 91 of the textile material 9, then it is possible to use the apparatus 1 according to the invention as sketched in FIG. 3 (or with its generalization with more than three groups ), the spatial frequencies 1 / a, 1 / (2a), l / (3a), ... determine. In this spatial frequency sequence, the intervals decrease monotonically. Such a non-arithmetic spatial frequency sequence may be advantageous because its members are rarely integer multiples of another member and thus higher Hannonians do not produce unwanted artifacts. This condition is fulfilled even better, and moreover approximates an arithmetic sequence, if only higher terms are taken into account, e.g. 1 / (1a), l / (12a), 1 / (13a), ... The equidistance a is, for example, between 0.1 mm and 10 mm.

Should one in the spatial frequency sequence equal intervals, d. H. an arithmetic sequence, there are various possibilities, two of which are illustrated in FIG. In these schematic representations, only the detection points 43.1 to 43.9 which are active in the corresponding case are symbolized with dots. In addition, a grid with the period a for the detection points 43.1-43.9 is located. On the right side, the respective spatial frequencies are indicated for the different cases. An "unit cell" 'of the grid consists of eight equidistant positions for the detection sites 43.1-43.8, so that the spatial frequencies 1 / a, 1 / (2a) and 1 / (4a) can be readily detected In the solution according to FIG. 4 (a) the detection points are left on the grid, and an approximation is made for the spatial frequency 3 / (4a) in that every fourth detection point is not used for the spatial frequency

Sums up contributes. The second solution according to FIG. 4 (b) deviates from the given grid in order to be able to detect the spatial frequency 3 / (4a) exactly. Both of the in Figure 4 solutions presented solve the task, the arithmetic spatial frequency sequence 1 / a. 3 / (4 a), 1 / (2a) and 1 / (4a); both have their advantages and disadvantages.

The schematic side views of elongate textile materials 9, eg yarns, of FIG. 5 will be used below to better explain the invention. The textile material 9 of Figure 5 (a) has a pronounced periodic structure with a location period P. For example, a diameter of the textile material 9 may change periodically with the longitudinal position. In contrast, in the textile material 9 of FIG. 5 (b), no location period can be recognized. Upon detection of light incident on one (e.g.

Comparison with the spatial period P or other structural feature of the textile material 9) short portion of the textile material 9 has been reflected or scattered, the light intensity detected at a detection point is a measure of the diameter of the

Textile material 9. Upon detection of light incident on one (as compared with the

Spatial period P or another structural feature of the textile material 9) short

Section of the textile material 9 was transmitted past, the detected

Light intensity is an inverse measure of the diameter of the fabric 9, d. H. the smaller, the larger the diameter.

Figure 6 (a) shows a possible course of an output signal of a light receiver 63.1, as it z. B. located in Figure 3, compared to the time t. If the location period P of the textile material 9 (see FIG. 5 (a)) coincides with the aquidistance a of two detection sites 43.1, 43.2 and the speed of movement of the textile material 9 is constant, the output signal is temporally periodic with a time period T. In FIG. 6 (a ) output signal has in addition to a periodic alternating component of the amplitude AS a DC component S ₀ . This DC component can thus be eliminated by a differential arrangement of detection sites as disclosed in EP-A-1 553 377. For such a differential arrangement two groups of equidistant detection sites with the same aquidistance a are used, which are separated by half the aquidistance a 2 in the direction 91 of the textile material 9. The output signal of the second group is subtracted from the output signal of the first group, thus resulting in the output signal shown in Figure 6 (b), which can be rectified, whereby the signal according to FIG. c) arises. In a further processing stage, the signal according to FIG. 6 (c) can be integrated over an integration time which is long in comparison with the time period. The size of the integral is a measure of a possible periodicity of Textilm aterials 9 with the

Location period P = a. A comparison of several such integrals for different equidistances a (or local periods P) results in a spatial spectrum of the textile material 9 (see FIG. 7). In other words: the inventive method and the

Device 1 according to the invention provides in a simple manner a Fourier spectrum of the structure of the textile material 9. The direct component So of the output signal according to FIG. 6 (a) can also be eliminated in a different way than with a differential arrangement of detection sites, for example by subtracting a current one Mean value of the output signal. Instead of the mentioned integration, a maximum value formation or a similar operation can be used, which is a measure of the amplitudes AS of the signals according to FIGS. 6 (a) or 6 (b). The mentioned operations such as subtraction, rectification, integration or maximum value formation can be carried out with analog and / or digital means; Both types of means and the corresponding signal transducers are well known today. Such agents may, for. B. in the illustrated in Figures 1 and 2

Electronic unit 70 and / or in a connected to the electronic unit 70

Be located evaluation.

FIG. 7 shows a location spectrum, as may result from the method according to the invention or the device 1 according to the invention. It is assumed that a device 1 with ten light receivers, which in each case a column 8. 1 - 8.10 of the diagram is assigned, for. For example, according to the following rules:

• A first column 8.1 at the left edge of the diagram is the one

Assigned light receiver, the light is supplied from all existing detection sites. It thus corresponds to the shortest local period P | ascertainable in the textile material (ie the highest spatial frequency).

· A second column 8.2 corresponds to the second shortest detectable in the textile material

Period P ₂ (ie, their second largest spatial frequency).

• Etc. "A tenth column 8.10 on the right-hand side of the diagram corresponds to the longest spatial period P ₁₀ detectable in the textile material (ie the smallest spatial frequency).

The height S * of a column 8.1 -8.10 is a measure of the amplitude AS of the light intensity received by the respective light receiver; she can z. B. correspond to the integral value described above. The column heights are preferably converted to normalized values, taking into account that with homogeneous illumination of all

Detection points the received light intensities would be different sizes. In the location spectrum of FIG. 7, a maximum can be observed at the location period P ₆ . This means that the examined textile material 9 has a periodic structure with the

Place period P «P ₆ has; see. FIG. 5 (a). If necessary, with appropriate statistical methods known to those skilled in the art, taking into account the finite heights of the adjacent columns 8.4-8.8, the location period P can be determined even more accurately. There may be textile materials 9, in which the inventive method provides two or more different spatial periods or spatial frequencies. For others

Textile materials 9, such as that of Figure 5 (b), the columns 8.1 -8.10 may all be about the same height, which means that no pronounced location period or

Spatial frequency was detected.

The diagram shown in FIG. 7, or a similar diagram, will become apparent from FIGS

Sum signals preferably automatically calculated and displayed on a (not shown) output unit of the inventive device, for example. A screen.

With the present invention, a speed of the textile material 9 in the direction of movement 91 can be determined. For this purpose, it is preferable to select an equidistance P of a group of detection sites corresponding to one in the

Site spectrum with large amplitude occurring period P heard; in the example of FIG. 7, P - P ". In the sum signal, which belongs to this group of detection sites, a predominant time frequency f is determined; in the example of Fig. 6 (a), f = 1 / T. The yarn speed v is the product of the location period P and the time frequency f: v = fP = P / T.

A speed measurement is possible even if no maximum is found in the location spectrum. One then selects any group of detection sites whose amplitude in the location spectrum is not equal to zero. In the sum signal, which belongs to this group of detection sites, again a predominant time frequency f is determined. The speed v is calculated according to the above formula.

An end of a waveguide 41 integrated on a substrate 2 facing the scanning region 3 is shown schematically in FIG. 8 in a greatly enlarged manner. It does not matter whether it is a lighting fiber or a

Detection waveguide acts because the two cases merge into each other by time reversal. The waveguide end is provided with a converging lens 44. The condenser lens 44 may be made from the waveguide end itself, glued to it directly, or spaced therefrom. It is designed and arranged in such a way that it lets as much light 31 emerging from the waveguide 41 impinge on the textile material 9 or couples as much light 31 coming from the textile material 9 into the waveguide 41 as possible. What is shown schematically in FIG. 8 as a single converging lens 44 can in practice be embodied as a lens system. The expert in the field of technical optics is in the knowledge of the invention able to determine a suitable arrangement for the purpose and use.

FIG. 9 shows a ninth embodiment of the device 1 according to the invention, in which the longitudinal axis 91 of the textile material 9 lies parallel to the plane of the substrate 2, but is spaced therefrom. Thus, the textile material 9 is moved over the substrate 2 along the longitudinal direction 91 of the textile material 9. Of the

Scanning region 3 is in or above the plane of the substrate 2. Light, the cut parts by means of a lighting waveguide 42 from a coupling 52 is guided to the scanning 3, is coupled out in the scanning area 3 to the textile material 9 out. After interaction with the textile material 9, for example, reflection and / or scattering on the same, at least part of this light is coupled into detection waveguides 41 .1 -41 .3 and from these to coupling-out interfaces 51 .1. 51 .2 guided. For coupling and uncoupling the light in the scanning region 3 are in this embodiment, optical Coupling elements 45 is required, which can couple light out of the plane of the substrate 2 or from the outside into a waveguide 41.2-41.3 integrated on the substrate 2. Such coupling elements 45 are known per se and need not be discussed further here. The coupling elements 45 may additionally be equipped with converging lenses and other optical components. Transmitter module and receiver module,

Lines and electronics unit are not shown in Figure 9 for the sake of simplicity; but they can be the same or similar as in Figures 1 or 2 executed.

The scanning at the detection sites may be optical, electrical and / or based on another physical principle. Not shown here

Embodiments may instead of or in addition to the optical waveguide structure 4 on the substrate 2 be integrated electrical circuits, as are known in the art of electronics. Such circuits may include passive and / or active electrical components in addition to electrical interconnects. Examples of such electrical components are resistors, capacitors, coils, transistors, filters and amplifiers. Even complex components such as microprocessors may be located on the substrate 2, which are preferably applied as integrated circuits in a separate housing on the substrate 2. The electrical conductor tracks can open into the scanning region 3, wherein the openings are preferably provided with electrodes. The

Electrodes serve to generate and / or detect an electric field, preferably an alternating electric field, in the scanning region 3. The textile material 9

interacts with the electric field and affects it. The electrical testing of the textile material 9 is based on detecting the effects of the textile material 9 on the electric field and on it to eat physical properties of the textile material 9 to sch Ii. The capacitive testing of textile material 9 is well known in the prior art. Analogously to the optical interface 55 and to the optical transmitter and receiver module 65 (see FIG. 2), the device 1 according to the invention can be equipped with an electrical interface and an electrical connection part. The electrical interface can be designed as a plug connection, as they are well known from electronics and available on the market.

In Ausführungsfornen not shown here, the device according to the invention, both an optical waveguide structure and an electrical conductor structure on be integrated with the same substrate 2, wherein both structures open at least partially into the scanning region 3. Thus, this Ausführungsfonn offers the possibility, the fabric 9 optionally optically, electrically or both visually and electrically to examine.

Of course, the present invention is not limited to those discussed above

Limited embodiments. With knowledge of the invention, the skilled person will be able to derive further variants, which also belong to the subject of the present invention. In particular, the discussed embodiments may be combined with each other as desired. The number of examples used in the drawings

Light sources, light receivers, waveguides, detection sites, waveguide ends, lenses, etc. is by no means to be understood as limiting.

LIST OF REFERENCE NUMBERS

1 device

2 substrate

3 scanning range

31 light beams

4 optical waveguide structure

41 detection waveguides

42 illumination waveguides

43 detection site

44 condenser lens

45 optical coupling element

51 decoupling interface

52 Einkoppelschnittstelie

53 mechanical positioning means

55 optical interface

61 receiver module

62 transmitter module

63 light receiver

64 light source

65 transmitter and receiver module

70 electronics unit

71, 72 electrical lines

8 pillars of the local spectrum

textile material

Longitudinal axis and direction of movement of the textile material

Claims

Method for detecting a periodic structure in a moving elongated

Textihnateriai (9),

characterized in that

the textile material (9) simultaneously at several discrete, along its

Scanned longitudinally (91) and equidistantly spaced detection sites (43.1 -43.9) is scanned,

at the detection points (43.1-43.9) detected scanning signals to a

Sum signal can be added and

due to temporal changes of the sum signal on a periodic structure of Textilmatcrials (9) is closed.

The method of claim 1, wherein

several groups of a plurality of discrete detection sites (43.1-43.9) are provided, wherein the detection sites (43.1-43.9) within each group are equidistant and the equidistances of the different groups are different,

in each group the detected sampling signals are added to a sum signal and

due to temporal changes of the individual sum signals periodic components in the structure of Textilmatcrials (9) are compared.

Method according to claim 2, wherein values of a quantity (S *) corresponding to the temporal changes for the several groups are automatically in one

Diagram are shown.

Method according to claim 3, wherein in the diagram each value is given with the equidistance (Pi-Pio) of the relevant group and / or with a spatial frequency, which in

Substantially corresponds to the reciprocal of the equidistance is called.

5. The method according to any one of claims 2-4. wherein the number of groups is between 2 and 50, preferably between 5 and 20.

6. The method according to any one of the preceding claims, wherein the number

Detection sites (43.1-43.9) between 5 and 500, preferably between 20 and 200, is located. 7. The method according to any one of the preceding claims, wherein all detection points (43.1 -43.9) lie on an equidistant grid.

8. The method of claim 7, wherein the Aquidistanz (a) of the grid is between 0.1 mm and 10 mm.

9. The method according to any one of the preceding claims, wherein the sampling is carried out optically at the detection points (43.1 -43.9).

10. The method of claim 9, wherein the sum signal is a sum of intensities of at the detection sites (43.1 -43.9) delektierten light components.

1 1. The method of claim 10, wherein the intensities are summed by means of merging optical waveguides (41.1 -41.7).

Method according to one of the preceding claims, wherein a speed

(v) of the Texti Imateri is determined as (9) by determining a predominant time frequency (f) in the sum signal and determining the velocity (v) as the product of the time frequency (f) and the equidistance (P) of the detection points (43.1- 43.9).

13 device (1) for detecting a periodic structure in a moving

oblong textiles (9),

marked by

a substrate (2) with

a plurality of discrete, along the longitudinal direction (91) of the textile material (9) arranged and equidistantly spaced detection sites (43.1-43.9) for the simultaneous optical scanning of the textile material (9) and an optical waveguide structure (4) integrated on the substrate (2) for merging light components detected at the detection points (43.1-43.9) and for guiding the merged light components to a decoupling interface (51) which is used to decouple light from the

Waveguide structure (4) is formed.

14. Device (1) according to claim 13, wherein the optical waveguide structure (4) is formed such that when merging a sum of intensities of the detected at the detection points (43.1-43.9) detected light components and the sum signal for decoupling cut parts (51 ) to be led.

15. Device (1) according to spoke 13 or 14, wherein the optical waveguide structure (4) has at least one branch with at least two branches. 16. Vomchtung (1) according to any one of claims 13-15, wherein the optical

Waveguide structure (4) at least one waveguide (41.1, 41.3, 41.5, 41.7) for conducting light to the detection points (43.1-43.9) includes.

17. Device (1) according to any one of claims 13-16, wherein the detection points (43.1- 43.9) are each provided with at least one converging lens (44).

1 8. Device (1) according to any one of claims 13-17, wherein Auskoppelschnittstelle (51) for connecting the W el 1 en 1 e i t er s t r u k t u r with an optical connector (61) is set up.

19. Device (1) according to any one of claims 13-18, wherein the Auskoppelschnittstelie (51) is attached to an edge of the substrate (2).

20. Device (1) according to any one of claims 13-19, wherein

on the substrate (2) several groups of a plurality of discrete

Detection sites (43.1-43.9) are arranged, wherein the detection sites (43.1- 43.9) within each group are equidistant and the equidistance of the different groups are different, and the optical waveguide structure (4) for merging each detected light components in each group and for guiding the individual

merged light components to a decoupling interface (51) is formed. 21. Device (1) according to claim 20, wherein the number of groups is between 2 and 50, preferably between 5 and 20.

22. Device (1) according to any one of claims 13-21, wherein the number

Detection sites (43.1 -43.9) between 5 and 500, preferably between 20 and 200, is located.

23. Device (1) according to any one of claims 13-22, wherein all detection sites

(43.1 -43.9) lie on an equidistant grid. 24. Device (1) according to claim 23, wherein the Aquidistanz (a) of the grid is between 0.1 mm and 10 mm.