Patent Application
20150219617
The present invention lies in the field of textile material testing. It relates to a device and a method for the optical inspection of a moving textile material, according to the preambles of the independent claims. The invention can be used for example in yarn testing devices in the textile laboratory or in yarn clearers on spinning or winding machines.
A large number of different devices are known for testing textile materials. Different sensor principles are used in the textile testing devices. The use of a specific sensor principle depends among other things on the property that needs to be detected optimally. Frequently used sensor principles, especially in yarn testing, are the following:
The capacitive sensor principle; cf. U.S. Pat. No. 6,346,819 B1. The textile material is guided through an air gap of a measuring capacitor. The measuring capacitor substantially measures the mass of the textile material contained in said capacitor. The capacitive sensor principle offers high measuring precision and a sensitivity which is stable over a long period of time. Its disadvantages are an undesirable sensitivity to changes in humidity and non-usability with electrically conductive textile materials.
The optical sensor principle; cf. WO-2004/044579 A1. 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 for the diameter of the textile material and/or its optical properties such as reflectivity or color. The optical sensor principle is less sensitive to changes in diameter and less stable in the long term than the capacitive one. It can nevertheless be advantageous, especially for such applications for which the capacitive sensor principle is unsuitable, e.g. in environments with strong fluctuations in humidity or for electrically conductive textile materials. Foreign substances which have a reflectivity which deviates strongly from the textile material can be detected in a simple manner by the optical sensor principle.
It has already been proposed to scan yarn with different sensor principles and to combine the sensor signals in the evaluation with each other. CN-2'896'282 Y thus mentions the combination of a capacitive and a photoelectric sensor for detecting the mass density and the diameter of the same yarn. WO-01/92875 A1 teaches the arrangement of two sensors in succession along the yarn path. A first one of the sensors measures the optical reflection on the yarn. A second one of the sensors capacitively or optically measures the mass or the diameter of the yarn. The output signals of the two sensors are evaluated according to specific evaluation criteria. At least two types of foreign substances can be distinguished from each other on the basis of the evaluation.
WO-93/13407 A1 provides an example for an optical yarn clearer measuring head for the detection of foreign fibers. The yarn that is moved through a measuring slit is illuminated by a light source with modulated light. A first sensor receives light reflected from the yarn and at the same time a second sensor receives light transmitted from the yarn. Conclusions on the presence of a foreign fiber in the yarn are drawn from the electrical signals that are output by the two sensors. Three-dimensional light feeders are provided for guiding light between the light source and the sensors and the measuring slit, which light feeders are arranged for example as hollow cavities that are mirror-coated on the inside.
U.S. Pat. No. 5,768,938 A reduces the need for space of the measuring head in comparison with WO-93/13407 A1, in that the light feeders are arranged in a plane which stands perpendicularly to the yarn. The light feeders are arranged as a three-dimensional body which transmits light and which is inserted into a three-dimensional base body. The base body also comprises a receiving opening for a light source. Even this apparatus still requires a relatively large amount of space. If a change in the optical scanning part is necessary, the entire measuring head would have to be newly designed and the respective production tools would have to be newly constructed, which is exceedingly laborious.
DE-38'30'665 A1 discloses an optoelectronic apparatus for thread monitoring. All active optoelectronic components such as light-emitting diodes and photo transistors are attached to a central unit. The central unit is connected by means of optical waveguides to several yarn stop motions, which are respectively situated at a thread running point. A yarn stop motion only consists of a circuit board with a thread guide eyelet. The ends of two optical waveguides connected to the central unit are inserted into a respective opening in the circuit board in such a way that they are situated opposite of each other.
An optoelectronic yarn sensor is known from DE-10'2007'040'224 A1. The components of the yarn sensor are arranged on a circuit board. An emitter diode emits light which is directed by a lens to the yarn. The light transmitted by the yarn is detected by a receiver diode. A portion of the light emitted by the emitter diode is split off by the lens and is supplied by an optical waveguide integrated in the lens to a monitor diode. The current of the emitter diode is controlled depending on the signal of the monitor diode, so that a constant emitted luminous intensity is obtained.
The circuit boards with integrated optical waveguide structures and integrated electrical conductor structures are generally known, e.g. from US-2010/0209854 A1.
It is an object of the present invention to provide a device for the optical scanning of a moving textile material which requires less space than the devices known from the state of the art. Furthermore, the device shall be usable in a versatile manner and can be changed or maintained with little effort.
These and other objects are achieved by the device in accordance with the invention as defined in the first claim. Advantageous embodiments are provided in the dependent claims.
In accordance with the invention, a substrate is used having at least one optical waveguide structure integrated thereon for the optical inspection of a moving, preferably elongated, textile material. An electrical conductor structure for electrically testing the moved textile material can additionally be integrated on the substrate.
A waveguide structure which is accommodated monolithically in or on the substrate shall be understood in this specification as an optical waveguide structure integrated on a substrate. The waveguide structure was originally produced on the substrate, e.g. by technologies such as photolithography and/or doping, which is in contrast to separate, discrete waveguides which are put subsequently on a substrate. The integrated optical waveguide structure is inseparably connected to the substrate. It contains a plurality of transparent dielectric layers with different refractive indexes. A core layer with a higher refractive index is embedded between an upper and a bottom layer with lower refractive indexes, so that light waves can be guided in the core layer. The waveguide structure can preferably contain micro strip waveguides which guide light in one direction and/or flat thin-layer waveguides in which light can propagate in two directions. In addition to the waveguides, it can contain further passive and/or active integrated optical components such as lenses, beam splitters, reflectors, filters, amplifiers, light sources and/or light receivers.
The device in accordance with the invention for the optical inspection of a moving, preferably elongated textile material also contains a substrate on which a scanning region for the optical scanning of the textile material is provided, and an optical waveguide structure which is integrated on the substrate and which opens at least partly into the scanning region.
In a preferred embodiment, at least two optical waveguides of the optical waveguide structure open into the scanning region. At least two waveguides can be arranged for guiding light towards the scanning region and at least two waveguides for guiding light away from the scanning region. The orifices of the waveguides that guide towards and away from the scanning region are preferably arranged in an alternating fashion adjacent to each other.
It is advantageous for avoiding light losses if at least one orifice of a waveguide to the scanning region is provided with a focusing lens.
The optical waveguide structure can comprise at least one junction with at least two branches. At least two of the branches can face the scanning region or face away from the scanning region.
In a further preferred embodiment, the substrate comprises at least one optical interface outside of the scanning region for connecting the at least one optical waveguide structure to one respective optical connecting part. The at least one interface preferably comprises mechanical positioning means for positioning the optical connecting part with respect to the substrate. An incoupling interface can be provided for incoupling light into at least one optical waveguide structure and an outcoupling interface which differs from the incoupling interface for outcoupling light from at least one optical waveguide structure. The at least one optical interface is preferably arranged for connecting at least two optical waveguides to an optical connecting part. It is preferably attached to an edge of the substrate.
The invention also relates to a combination of a device in accordance with the invention, which comprises the aforementioned at least one optical interface, with an optical connecting part. An incoupling connecting part which is associated with the incoupling interface can contain a row of at least two light sources, preferably a light-emitting diode array, and an outcoupling connecting part which is associated with the outcoupling interface can contain a row of at least two light receivers, preferably a CCD array.
According to a further preferred embodiment, an electrical conductor structure is additionally integrated on the substrate, which structure opens at least partly into the scanning region. The textile material can thus selectively be examined in an optical, electrical or both optical and also electrical manner. Advantageously, at least two electrical conductor paths of the electrical conductor structure open into the scanning region. The orifices of the optical waveguides and the orifices of the electrical conductor paths can be arranged in an alternating fashion adjacent to each other. At least one orifice of an electrical conductor path is preferably provided with an electrode in the scanning region. The substrate can comprise at least one electrical interface for connecting the at least one electrical conductor structure to one respective electrical connecting part outside of the scanning region. The at least one electrical interface preferably comprises mechanical positioning means for positioning the electrical connecting part with respect to the substrate. It is attached to an edge of the substrate for example.
In the case of devices having a substrate with an optical waveguide structure and an electrical conductor structure, the substrate can comprise at least one optical-electric interface for connecting the at least one optical waveguide structure and the at least one electrical conductor structure to a respective optical-electrical connecting part outside of the scanning region. The at least one optical-electrical interface preferably comprises mechanical positioning means for positioning the optical-electrical connecting part with respect to the substrate.
The integration of the optical waveguide structure on the substrate leads to space saving with respect to known optical devices for testing textile materials. Furthermore, the substrate can be exchanged easily in the device in accordance with the invention in order to maintain or change the device. A change in the device can occur by the replacement of a specific substrate by another substrate in that the scanning region for example is arranged differently. A first substrate can be provided for example by means of which the textile material is examined from only one side, and a second substrate by means of which the textile material is examined from several directions along its circumference.
In the present specification, the terms such as “light” or “illuminating” are not only used for visible light, but also for electromagnetic radiation from the adjacent spectral ranges of ultraviolet (UV) and infrared (IR).
The invention is explained below in closer detail by reference to the schematic drawings, wherein:
The scanning region 3 is arranged in the present embodiment as a substantially semicircular recess at an edge of the substrate 2. The textile material 9 is guided through the device 1 in such a way that its longitudinal axis is situated as close as possible to the center point of the semicircle. The plane of the substrate 2 lies perpendicularly to the longitudinal axis of the textile material 9.
An optical waveguide structure 4 is integrated on the substrate 2 for guiding light towards the scanning region 3 and/or away from the scanning region 3. In the embodiment of
Light-collecting elements 42 such as focusing lenses are preferably attached in the scanning region 3 to the orifices of the waveguides 41.1 to 41.8 in order to ensure the highest possible light yield. It is known that light exiting from the end of a thin waveguide is emitted in a large opening angle. In temporal reversal, light from the same large opening angle is therefore incoupled into the waveguide. Since the textile material 9 to be tested mostly has a small diameter of less than 1 mm, it would be struck without countermeasures by merely a small portion of the available light, and from said light only a small part would be incoupled into a waveguide again. The focusing lenses 42 are used to avoid such losses of light. Their function and their configuration are explained below in closer detail by reference to
Four of the eight waveguides 41.1 to 41.8, which are designated below as “illumination waveguides” 41.1, 41.3, 41.5, 41.7, are used for illuminating the textile material 9. For this purpose, they receive light from an emitter module 61 and guide it to the scanning region 3, where it exits from the illumination waveguides 41.1, 41.3, 41.5, 41.7 and impinges on the textile material 9 at least in part. The emitter module 61 can be attached to the end of a first electrical conductor 71. The light transfer from the emitter module 61 to the illumination waveguides 41.1, 41.3, 41.5, 41.7 occurs on an incoupling interface 51 which is attached to an edge of the substrate 2. The incoupling interface 51 can be arranged as a plug-in connection for example. The emitter module 61 contains light sources 63 which are arranged adjacently in a row for example and of which each is assigned to one of the four illumination waveguides 41.1, 41.3, 41.5, 41.7. The light sources 63 can be arranged as diode lasers or light-emitting diodes. The incoupling of the light from the light sources 63 into the illumination waveguides 41.1, 41.3, 41.5, 41.7 can occur by direct illumination of the ends of the illumination waveguides or by means of optical elements such as mirrors and/or focusing lenses 42. In the latter case, similar lenses can be used as in the orifice to the scanning region 3 (see
The other four of the eight waveguides 41.1 to 41.8 are used for detecting the light reflected from the textile material 9 or transmitted past said material, and are therefore designated below as “detection waveguides” 41.2, 41.4, 41.6, 41.8. They guide the light coming from the scanning region 3 to a receiver module 62, which can be attached to the end of a second electric conductor 72. The light transfer from the detection waveguides 41.2, 41.4, 41.6, 41.8 to the receiver module 62 occurs at an outcoupling interface 52 which is attached to an edge of the substrate 2. The outcoupling interface 52 can also be arranged as a plug-in connection with respective positioning means 53. The receiver module 62 contains light receivers 64 which are arranged in a row adjacent to each other for example and each of which is assigned to one of the four detection waveguides 41.2, 41.4, 41.6, 41.8. The row of light receivers can be arranged as a CCD array for example. It is also possible to combine several receiver elements situated adjacent to each other, which then form an “assembled light receiver” and are assigned to a detection waveguide 41.2, 41.4, 41.6, 41.8. Concerning light outcoupling and the positioning and arrangement of the outcoupling interface 52, the same applies as already discussed analogously with respect to the incoupling interface 51.
The emitter module 61 and the receiver module 62 are connected via the first electrical conductor 71 and the second electrical conductor 72 to an electronic unit 70. It triggers the emitter module 61 on the one hand, and on the other hand the electronic unit 70 receives signals from the receiver module 62, evaluates them itself or conducts them, after optional preprocessing, to an evaluation unit (not shown).
It is advantageous to precisely define the incoupling interface 51 and the outcoupling interface 52 in an optical and mechanical manner and to thus quasi standardize them. As a result, the emitter module 61 and the receiver module 62 with their relatively expensive optoelectronic components can be used without any changes for various substrates 2. On the other hand, the relatively inexpensive substrates 2 with their integrated optical waveguide structures 4 can be exchanged as required. There may be a need for exchanging a substrate 2 for example if a different waveguide structure 4 (especially in the scanning region 3) is needed or if a substrate 2 is damaged by wear and tear or is defective for other reasons.
The device 1 in accordance with the invention is preferably housed in a housing as known for example from U.S. Pat. No. 5,768,938 A. Such a housing was not included in the enclosed drawings for reasons of clarity of the illustration.
The junctions can be arranged as generally known junction components. Similar to the example of
A third embodiment of the device 1 in accordance with the invention, which also contains a Y-junction, is shown in
The optical waveguide structure 4 and the optical interface 51 in the embodiment of
The electrical conductor structure 104 is arranged in a very simple way in
The orifices of the electrical conductor paths 141.1 to 141.4 in the scanning region 3 are provided with electrodes 142. The electrodes 142 are used to produce and/or detect an electrical field, preferably an alternating electrical field, in the scanning region 3. The textile material 9 interacts with the electrical field and influences it. The electrical testing of the textile material 9 is based on detecting the influences of the textile material 9 on the electrical field and to derive therefrom the physical properties of the textile material 9. The capacitive testing of textile material is sufficiently known from the state of the art. In the present embodiment, two electrodes 142.1, 142.3 are used as transmitter electrodes, and the other two electrodes 142.2, 142.4 as receiver electrodes.
Similar to the optical interface 55 and to the optical transmitter and receiver module 65, the device 1 according to
The sixth embodiment of the device 1 in accordance with the invention, which is shown in
The two light sources 63 and the two transmitter electrodes 142.1, 142.3 are triggered by a respective signal generator 167. The signal generators 167 are shown in
In the embodiment of
It is understood that the present invention is not limited to the embodiments as discussed above. With knowledge of the invention, the person skilled in the art will be able to derive further variants which also belong to the subject matter of the present invention. In particular, the discussed embodiments can be combined with each other in an arbitrary fashion. Although many of the enclosed drawings are shown with axial-symmetric substrate forms and waveguide structures for aesthetic reasons, such symmetry is not necessary for the present invention. Asymmetric arrangements might be preferable in practice depending on the application. Furthermore, the number of light sources, light receivers, waveguides, ends of waveguides, lenses et cetera which are used in the drawings by way of example, shall in no way be understood as limiting.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2739/12 | Dec 2012 | CH | national |
This application is a continuation application of prior pending PCT patent application PCT/CH2013/000209 filed 2013 Dec. 2, and claims priority on Swiss patent application 2739/12 filed 2012 Dec. 10.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CH2013/000209 | Dec 2013 | US |
| Child | 14688411 | US |
