TECHNOLOGICAL BACKGROUND OF THE INVENTION

Field of application

The present invention relates to the field of sensors for optical analysis of a thread or yarn fed to a textile machine. In particular, the invention relates to an innovative method for manufacturing an optical sensor for detecting the characteristics of a thread or yarn fed to a textile machine which is simple and inexpensive to manufacture. A further object of the present invention is an optical sensor manufactured by the aforesaid method.

Prior art

Optical sensor devices employable in the textile industry commonly use a transmitter component of an electromagnetic radiation signal, e.g., in the infrared radiation range, and a receiver component sensitive to this infrared radiation, e.g., a charge-coupled device or CCD, between which the thread or yarn to be checked is placed and made to run. Any changes in the infrared radiation signal detected by the receiver component over time are indicative of a change in the characteristics of the checked thread or of defects in the thread.

Generally, the transmitter (electromagnetic radiation emitter) and receiver components of the optical sensor are associated with an electronic board, which also includes electronic control circuits of the sensor.

To be used in the textile industry, the containing casings of the sensor emitter and receiver components must be such to provide a high degree of protection (IP code or IP ingress protection rating) to these components, against the introduction of solid particles (e.g., such as dirt and dust) and/or the access of liquids (e.g., oils), which could damage them or impair their proper operation.

To meet these requirements, known optical sensors usable in the textile industry are manufactured by placing, at an initial step of processing, the aforesaid electronic board, which includes the transmitter and receiver components of the sensor, inside a box-like casing.

This box-like casing generally includes a first casing portion, comprising a compartment for housing the electronic board, and a second casing portion having the function of a cover and fixable to the first casing portion to close this compartment once the electronic board is inserted.

Furthermore, the manufacturing process of the known optical sensor involves the placement of some lenses inside the box-like casing to allow the infrared radiation to adequately illuminate the sensitive receiver component which detects the state of the thread or yarn fed to the textile machine.

Generally, the box-like casing containing the sensor is made of conductive material, preferably metal, to ensure shielding of the sensitive receiver component and the electronic control circuits it contains from external electromagnetic radiation.

It is worth noting that the fixing of the second portion of the box-like casing to the first portion of the casing is, for example, achieved by ultrasounds.

Once the two portions of the box-like casing have been fixed together, a step of injecting resin into the casing is required to fill it. This resin is configured to seal the electronic board of the sensor, preventing the introduction of external elements and the contamination of the sensor.

Before the aforesaid step of resin injecting, a step of checking the perfect sealing of the box-like casing containing the electronic board is provided to prevent unwanted resin leakage during the filling process.

It is worth noting that the known optical sensor manufacturing process described above has limitations and drawbacks.

Indeed, this manufacturing process involves many processing steps: molding and preparing the first portion of the casing and the second portion of the casing; inserting the electronic board inside the first portion of the casing; fixing by ultrasounds the second portion of the casing to the first portion; checking the closure of the box-like casing containing the electronic board; and injecting the sealing resin.

To be performed, the processing steps require moving the semi-finished product to different processing stations (component assembly, resin injection, etc.), resulting in time-consuming work to complete the manufacturing of a single device.

Furthermore, the injection of the sealing resin inside the box-like casing does not always allow the optical sensor electronic board to be perfectly sealed. Indeed, in some cases, the optical sensors of known type are less resistant to contaminations by external elements.

SUMMARY OF THE INVENTION

It is the object of the present invention to devise and make available a method for manufacturing an optical sensor for detecting the characteristics of a thread or yarn fed to a textile machine, which makes it possible to overcome, at least partially, the limitations and drawbacks of known manufacturing methods of optical sensors employable for the same purposes.

This purpose is achieved by a method for manufacturing an optical sensor for detecting the characteristics of a thread or yarn fed to a textile machine according to claim 1.

The method of the invention comprises the steps of:

- making available (201) a sensor module (50) of the optical sensor comprising:

- an electronic board (1) which includes sensitive components (2, 2', 3) of the optical sensor and an electronic control circuit (4) connected to said sensitive components (2, 2', 3);

- an electrical connection element (5; 5') connected to the electronic board to allow the connection of the electronic board to apparatuses external to the optical sensor.

After having placed and locked (202) the sensor module in an injection molding apparatus (30), the method involves: - injecting (203), through the molding apparatus, a molten thermoplastic material onto the sensor module to completely coat the electronic board and at least one portion of the electrical connection element with the molten thermoplastic material;

- cooling (204) the thermoplastic coating material to mold a body (10; 10') of the optical sensor adapted to encapsulate and seal the electronic board (1) and said at least one portion of the electrical connection element.

Preferred embodiments of the aforesaid method are described in the dependent claims.

It is a further object of the present invention a sensor for optical analysis of a thread or yarn in a textile machine according to claims 17, 18, 19 and 20 manufactured with the aforesaid method. BRIEF DESCRIPTION OF THE DRAWINGS Further features and advantages of the manufacturing method of an optical sensor for detecting the characteristics of a thread or yarn fed to a textile machine according to the invention will be apparent in the following description that illustrates preferred embodiments, given by way of indicative and non-limiting examples, with reference to the accompanying figures, in which: - figure 1 illustrates, in a perspective view, a first embodiment of an optical sensor for detecting the characteristics of a thread or yarn fed to a textile machine manufactured according to the method of the present invention;

- figure 2 illustrates, in perspective and exploded view, a sensor module of the optical sensor of figure 1 before performing a step of injection molding of the method of the invention;

- figure 3 illustrates, in perspective view, a cutaway of an injection molding apparatus, free from a covering element, and two sensor modules of figure 2 in an assembled configuration, wherein such sensor modules are placed in the injection molding apparatus before performing the operative steps of injecting and molding;

- figure 4 illustrates, in perspective view, a cutaway of the injection molding apparatus of figure 3 including two optical sensors of figure 1 obtained by the method of the invention at the end of the operative step of molding;

- figures 5 and 6 illustrate a second embodiment of the optical sensor to detect the characteristics of a thread or yarn fed to a textile machine made by the manufacturing method of the invention, in an exploded and assembled configuration, respectively; - figure 7 shows a flow chart of the operative steps of the method for manufacturing an optical sensor adapted to detect the characteristics of a thread or yarn fed to a textile machine of the invention;

- figure 8 shows a flow chart of the operative steps of a second example of the manufacturing method of the optical sensor of the invention;

- figures 9, 10, and 11 illustrate a third embodiment of the optical sensor for detecting the characteristics of a thread or yarn fed to a textile machine implemented with the manufacturing method of the invention, in perspective view, front view, and a bottom view, respectively.

Similar or equivalent elements in the aforesaid figures are indicated by means of the same reference numerals. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to figures 1-4, numerical reference 100 is used to indicate overall a first example of an optical sensor for detecting the characteristics of a thread or yarn F fed to a textile machine manufactured according to the method of the present invention.

In figure 1, this thread or yarn F to be examined by the optical sensor 100 is diagrammatically represented by a dashed line.

In a general embodiment, with reference to figure 2, the optical sensor or sensor 100 comprises a sensor module 50. This sensor module 50 comprises an electronic board 1, in particular, a printed circuit board (PCB) configured to house sensitive components 2, 2', 3 of the optical sensor 100 and an electronic circuit 4 controlling such sensitive components 2, 2', 3 of the sensor connected thereto.

In further detail, the electronic board 1 of the sensor module 50 comprises a board body portion la connected in one piece to a detection portion lb, e.g., shaped as an open loop, and configured to be operationally associated with the thread or yarn F to be examined.

For example, the sensitive components 2, 2', 3 of the sensor module 50 of the optical sensor 100 are associated with the detection portion lb of the electronic board 1. The electronic control circuit 4 of the sensor 100 is associated, for example, with the board body portion la.

In particular, this detection portion lb of the electronic board 1 of the sensor module 50 consists of two arms protruding from the board body portion la and coplanar with this board body portion. Such protruding arms are adapted to delimit an area lc in which the thread or yarn F to be examined can run. In an embodiment, the sensitive components 2, 2', 3 of the sensor module 50 comprise at least one electromagnetic radiation emitter component 2, 2', e.g., in the infrared radiation range, and a receiver component 3 sensitive to this radiation, e.g., a charge- coupled device or CCD.

In particular, in the example in figure 2, the sensor module 50 comprises two infrared electromagnetic radiation emitting components 2 and 2', each of which is fixed to one end of an arm of the detection portion lb of the electronic board 1 distal from the body portion of the board la. Such electromagnetic radiation emitting components 2 and 2' are preferably oriented toward the center of the receiver component 3 fixed to the aforesaid detection portion lb of the board so that the thread or yarn F to be examined, running in area lc, is interposed between the receiver component 3 and each of the aforesaid emitter components 2 and 2'.

Furthermore, the electronic control circuit 4 of the sensor module 50, associated with the body portion of board la, is electrically connected to the emitter 2, 2' and receiver 3 components to control them. For example, this electronic control circuit 4 comprises a microprocessor unit of a type known in itself.

Furthermore, the sensor module 50 comprises an electrical connection element 5, in particular an electrical cable 5, connected to electronic board 1 to connect this electronic board 1 to apparatuses external to the optical sensor 100. In particular, the electronic control circuit 4 is configured to receive/send electrical signals from/to the outside of the optical sensor 100 through this electrical cable 5.

In an embodiment, the sensor module 50 of the optical sensor 100 further comprises a lens 6 configured to operate as a thread guide. In the example in figure 2, this lens 6 has a body C shaped as an arc of a circumference or an open loop.

In particular, this lens 6 is configured to be fixed to the detection portion lb of the electronic board 1 to surround the area lc in which thread or yarn F to be examined can run.

This lens 6 operates as a thread guide in that the thread F to be controlled, fed to a textile machine (not shown), is made to move within the arc of circumference, in the case of lens with open-loop body C, delimited by lens 6. In this manner, the optical sensor 100 is configured to stop the machine if the thread F should break and prevents this machine from continuing the production of artifacts which would inevitably be imperfect and thus to be discarded. This lens 6 is manufactured from plastic or ceramic. In an embodiment, this lens 6 is manufactured from a textile ceramic. In a further embodiment, this lens 6 is manufactured from a textile ceramic type which is transparent to infrared electromagnetic radiation.

This lens 6, in addition to being transparent to infrared radiation, is also made of a material which is resistant to wear and thus adapted to keep in contact, if necessary, with yarn F itself without being damaged.

For example, the transparent textile ceramic from which lens 6 is made is aluminum oxide (AI2O3)• Alternatively, this lens 6 can be made of sapphire glass, polyamide 12 or nylon 12 (PA12).

In addition to acting as a thread guide, at the same time, the lens 6 prevents dirt or dust from being deposited on the receiver component 3 of the sensor 100, which would alter its functionality.

In a further embodiment, the sensor module 50 of the optical sensor 100 comprises, in addition to, or as an alternative to lens 6, a diaphragm element 7 configured to be inserted or fitted on the receiver component 3 of the sensor 100.

This diaphragm 7 is made of plastic, e.g., polyamide 6 (PA6), and is configured to shield the receiver component 3 from external light and to channel the infrared radiation from the emitter components 2, 2', instead. This maximizes the infrared radiation from each emitter 2, 2' on the receiver component 3, improving the reading of the characteristics of the thread F.

In a further embodiment, the sensor module 50 of the optical sensor 100 can also comprise additional lens elements (not shown in figure 2) configured to amplify the light of signal LEDs (not shown in the figures) associated with the electronic board 1.

This additional lens elements are, for example, associated with end portions 10a of the optical sensor 100 in figure 1.

In a further advantageous embodiment, the sensor module 50 of the optical sensor 100 comprises, either in addition to or as an alternative to lens 6 and diaphragm element 7, an electromagnetic shielding element 8 fixable to the electronic board 1 to protect both the receiver component 3 of the sensor 100 and the electronic circuit 4 of the circuit board 1 from the external electromagnetic radiation.

This electromagnetic shielding element 8 is made of metal material, e.g., AISI 304 stainless steel.

In particular, this shielding element 8 comprises a first 80 and a second 81 metal plate mutually opposed, e.g., U-shaped. This first 80 and second 81 metal plates are parallel to each other and connected through a metal connecting element 82 made in one piece with the aforesaid first 80 and second 81 plates.

In an embodiment, the first 80 and second 81 metal plates each comprise a plurality of lightening through- holes 84, in particular four circular holes.

Furthermore, the aforesaid metal connecting element 82 of the shielding element 8 comprises a respective through-hole 83, in particular rectangular, configured to be engaged by a respective tooth 15 arranged on an edge of the circuit board 1 to fix the shielding element 8 onto the circuit board 1 itself. Once the shielding element 8 has been fixed to electronic board 1, the electronic board 1 is interposed between the above- mentioned first 80 and second 81 metal plates of the shielding element 8.

In reference to figure 2, the numerical reference 50 indicates, as a whole, the sensor module that represents a semi-finished product of the optical sensor 100 manufactured by the method of the invention. In the example of figure 2, this sensor module 50 comprises: the electronic board 1 described above equipped with the respective electrical connection cable 5; the lens 6 described above configured to operate as a thread guide; the diaphragm element 7 described above and possibly additional lenses; the electromagnetic shielding element 8 described above.

However, in the most general embodiment of the optical sensor 100, this sensor module 50 comprises only the electronic board 1 connected to the respective electrical connection cable 5.

In a first advantageous embodiment of the optical sensor 100, the sensor module 50 also comprises the electromagnetic shielding element 8 in addition to the electronic board 1 connected to the respective cable 5.

In further advantageous embodiments of the optical sensor 100, the sensor module 50 comprises, in addition to the electronic board 1 connected to the electrical cable 5 and to the electromagnetic shielding element 8, also: the lens 6 configured to operate as a thread guide and/or the diaphragm element 7 and/or the additional lenses.

Again, with reference to figure 1, the optical sensor 100 comprises a body 10 consisting of a thermoplastic material, in particular a thermoplastic resin. This thermoplastic resin is configured to completely coat and encapsulate the sensor module 50 of the optical sensor 100 according to any one of the embodiments described above, sealing it.

It is worth noting that this body 10 of the optical sensor 100 is obtained by injection molding, at low temperature and low pressure, the aforesaid thermoplastic resin (hot-melt molding) on the sensor module 50 performed by means of an appropriate molding apparatus 30.

For example, a molding temperature of the method of the present invention is defined as "low" when this molding temperature is in the range of 180°C to 280°C. Regarding the molding pressure, in the process of the present invention, the molding pressure is defined as "low" when this pressure is in the range of 0.8 Bar to 3 Bar.

It is worth noting that the method of the invention requires the use of a thermoplastic resin having properties such that it can be injected at low temperature and low pressure into the molding apparatus 30 to avoid damaging the circuitry of the electronic board 1 during the molding step.

In the most general embodiment in which the sensor module 50 comprises only the electronic board 1 connected to the respective electrical connection cable 5, following the injection molding operation, the aforesaid thermoplastic resin or hot-melt resin is configured to completely coat the electronic board 1 and at least a part of the electrical connection cable 5 to mold or form, after the cooling of the resin, the body 10 of the optical sensor 100 in a single pass.

Figure 3 shows a cutaway of an example of an injection molding apparatus 30 (free from an upper cover portion) employable in the manufacturing method of the invention.

The aforesaid molding step initially involves placing the sensor module 50, in an assembled configuration, into the molding apparatus or mold 30. In the example of figure 3, two similar sensor modules 50 are placed in the mold 30, each corresponding to the sensor module 50 of figure 2.

As represented in figure 4, which shows a cutaway of the injection molding apparatus 30 of figure 3 once the operation of injecting resin into the mold to cover the sensor modules 50 is completed, after cooling the thermoplastic resin, the method of the invention makes available two optical sensors 100, each of which is similar to the optical sensor 100 of figure 1.

It is worth noting that this thermoplastic resin or hot-melt resin used in the injection molding step of the method of the invention to make the body 10 of the optical sensor 100 comprises a polymer based on polyamide.

This polymer resin is characterized by the following properties :

- absence of corrosive elements in the mixture, which could be released on the electronic board 1 of sensor 100 causing corrosion of the optical/electrical/electronic components housed therein;

- low water absorption values, e.g., about 2.8% at 23°C, to prevent this polymer resin from absorbing moisture from the environment;

- resistance to external agents, such as oils, gasoline, and the like;

- transparency to infrared radiation;

- a hardness value of about 45 Shore D and a yield strength value, e.g., greater than 2.8 MPa, to prevent any thermal expansion from tearing/damaging the electronic components from the circuit board 1.

An additional embodiment of an optical sensor 100' for detecting the characteristics of a thread or yarn F fed to a textile machine which can be manufactured with the manufacturing method of the invention is described with reference to figures 9, 10 and 11, respectively in perspective view, front view and a bottom view.

In particular, this optical sensor 100' comprises a sensor module similar to that described with reference to sensor 100. This sensor module comprises an electronic board, configured to house the sensitive components of the optical sensor 100' and an electronic circuit to control the sensitive sensor components.

Furthermore, the sensor module of the sensor 100' comprises a respective electrical connection element 5' connected to the electronic board to connect it to the external apparatuses to the optical sensor 100'. In the example of figures 9-11, this electrical connection element is embodied in one or more electrical connectors 5' configured to operate from sensor interface connections 100'.

In the most general embodiment, in which the sensor module comprises only the electronic board connected to one or more electrical connectors 5', after the injection molding operation, the thermoplastic resin or hot-melt resin is configured to completely coat the electronic board and at least part of the electrical connector 5' to mold or form, after the cooling of the resin, the body 10' of the optical sensor 100' in a single pass.

In the example of figures 9-10, the optical sensor 100' further comprises a respective lens 6' configured to operate as a thread guide. In particular, this lens 6' has a body C' shaped as a closed loop to surround an area in which the thread or yarn F to be examined can run. This lens 6' is similar to the lens 6 described above with reference to the sensor 100 in terms of manufacturing materials and functional aspects.

Again, with reference to the example in figures 9- 10, the body 10' of the aforesaid optical sensor 100' comprises a first face 92' and an opposite second face 93' mutually connected by respective sides 91' of the body 10' of the sensor 100'.

Furthermore, a respective through-hole 95' is made in the body 10' of the optical sensor 100.

In an embodiment, the optical sensor 100' further comprises the electromagnetic shielding element 8 described above in addition to the electronic board connected to the respective electrical connector 5'.

In further embodiments, the optical sensor 100' comprises, in addition to the electronic board connected to the connector 5' and to the electromagnetic shielding element 8 also: the closed-loop lens 6' configured to operate as a thread guide and/or the diaphragm element 7 described above and/or the additional lenses.

An embodiment of a further optical sensor 100A for detecting the characteristics of a thread or yarn F fed to a textile machine which can be manufactured with the manufacturing method of the invention is described with reference to figures 5-6, respectively, rn exploded and assembled configuration view.

In particular, this additional optical sensor 100A comprises the optical sensor 100, described with reference to figures 1-2, and a first 90 and second 91 metal half-shells coating the optical sensor 100. In greater detail, each of the aforesaid first 90 and second 91 metal coating half-shells is shaped to be applied to one of two opposite faces of the body 10 of the aforesaid optical sensor 100, e.g., a first face 92 and an opposite second face 93, to coat the body 10 of the optical sensor 100.

In particular, the first 90 and second 91 metal coating half-shells are attached to the thermoplastic material body 10 of the optical sensor 100 by at least one mechanical fixing element 94, e.g., a fixing sleeve. This at least one mechanical fixing element 94 is configured to engage respective through-holes 95, 96 obtained in the body 10 of the optical sensor 100 and in the aforesaid first 90 and second 91 metal coating half- shells, respectively.

In the example of figure 5, the additional optical sensor 100A comprises two fixing sleeves 94 adapted to engage two through-holes 95, 96 obtained in the body 10 of the optical sensor 100 and in the aforesaid first 90 and second 91 metal half-shells.

The first 90 and second 91 metal half-shells, e.g., made of AISI 304 stainless steel, are adapted to provide additional shielding to the additional optical sensor 100A, either in addition to or instead of the electromagnetic shielding provided by the shielding element 8 of the above-mentioned sensor module 50.

Furthermore, the first 90 and the second 91 metal half-shells are configured to impart greater mechanical robustness to the additional optical sensor 100A, should the thread F rub against the surface of the sensor body, either accidentally or continuously.

Additionally, the first 90 and the second 91 metal half-shells are used for appearance purposes because they modify the appearance of the additional 100A optical sensor.

Although the example described above involves the embodiment of the further optical sensor 100A obtained by coating the body of the optical sensor 100 shown in figures 1-2 with the first 90 and second 91 metal half- shells, a further optical sensor obtained by coating the body 10' of the optical sensor 100' in figures 9-11 can be made similarly. In this case, respective metal half- shells shaped to be applied to the first face 92' and the opposing second face 93' of the body 10' of the sensor 100' are used.

With reference to figures 7-8, the following describes in more detail the operational steps of a manufacturing method 200, 300 for the optical sensor 100, 100', 100A adapted to detect the characteristics of a thread or yarn F fed to a textile machine of the invention.

The manufacturing method 200, 300 of figures 7-8 begins with a symbolic step of starting "STR" and ends with a symbolic step of ending "ED".

In the most general embodiment, the manufacturing method 200, 300 of an optical sensor 100, 100', 100A comprises a step 201 of making available a sensor module 50 of the optical sensor. This sensor module 50 comprises:

- an electronic board 1, which includes sensitive components 2, 2', 3 of the optical sensor 100, 100A and an electronic control circuit 4 connected to the sensitive components 2, 2', 3;

- an electrical connection element 5, 5', e.g., an electrical cable or one or more electrical connectors, connected to the electronic board 1 to allow the connection of the electronic board 1 to apparatuses external to the optical sensor.

The method 200, 300 comprises a step of placing and locking 202 the sensor module 50 in an injection molding apparatus 30.

Subsequently, a step of injecting 203 is provided, through said molding apparatus 30, a molten thermoplastic material onto the aforesaid sensor module 50 to completely coat the aforesaid electronic board 1 and at least one portion of the electrical connection element 5, 5' with this molten thermoplastic material.

The method 200, 300 involves cooling 204 the thermoplastic coating material to mold a body 10; 10' of the optical sensor 100; 100'; 100A adapted to encapsulate and seal the electronic board 1 and the at least one portion of the electrical connection element 5, 5'.

In an embodiment of the invention, the thermoplastic coating material is a thermoplastic resin.

Furthermore, the aforesaid step of injecting 203 the thermoplastic material through the injection molding apparatus 30 is performed using a thermoplastic resin melt at a molding temperature in the range of 180°C- 280°C and a molding pressure in the range of 0.8 Bar-3 Bar.

In an embodiment of the method 200, 300 for manufacturing an optical sensor 100, 100', 100A according to the invention, the aforesaid step of making available 201 a sensor module 50 comprises a further step 201a of fixing an electromagnetic shielding element 8, made of metal material, to the electronic board 1.

In greater detail, this electromagnetic shielding element 8 comprises a first 80 and an opposite second 81 metal plate, parallel to each other and connected to each other through a metal connecting element 82 made in one piece with the aforesaid first 80 and second 81 metal plates; when the electromagnetic shielding element 8 is fixed to the electronic board 1, the method of the invention provides a step of interposing the electronic board 1 between said first 80 and second 81 metal plates.

With reference to figure 8, in a further embodiment, the manufacturing method 300 for an optical sensor 100A according to the invention comprises the further steps of:

- applying 301 a first 90 metal half-shell to a first face 92, 92' of the molded body 10, 10' of the optical sensor to coat this first face 92, 92';

- applying 302 a second 91 metal half-shell to a second face 93, 93' of the molded body 10, 10' of the optical sensor opposite to this first face 92, 92' to coat said second face 93, 93'; the first 90 and the second 91 metal half-shells applied to the first 92, 92' and second 93, 93' faces of the body 10, 10' are shaped also to coat at least partially the connecting sides 97, 97' of the body 10, 10' of the sensor 100, 100' between the aforesaid first 92, 92' and second 93, 93' faces.

In an embodiment, the aforesaid steps of applying a first 90 and a second 91 metal coating half-shell comprise the further step of fixing said first 90 and second 91 metal half-shells to the body 10, 10' of the sensor 100 by means of at least one mechanical fixing element 94.

In particular, this at least one mechanical fastener 94 comprises a fixing sleeve configured to engage respective through-holes 95, 96, 95' made in the body 10, 10' of the optical sensor 100, 100' and in the aforesaid first 90 and second 91 metal coating half- shells, respectively.

Again with reference to figure 7, in a further embodiment of the method 200, 300, the step of making available 201 a sensor module 50 comprises a further step 201b of making available said electronic board 1 comprising a body portion of the board la connected in one piece to a detection portion lb shaped as an open loop and configured to be operatively associated with the thread or yarn F to be examined; the sensitive components 2, 2', 3 of optical sensor 100, 100A are associated with the detection portion lb of the electronic board 1; the control electronic circuit 4 is associated with the body portion of board la.

In a further embodiment of the method 200, 300, the step of making available 201 a sensor module 50 comprises a further step 201c of fixing a lens 6, 6' having an open-loop C or closed-loop C' shaped body, to the detection portion lb of the electronic board 1 to surround an area lc in which the thread or yarn F to be examined can run.

In a further embodiment of the method 200, 300, the step of making available 201 a sensor module 50 comprises a further step 201d of fitting a diaphragm element 7 made of plastic material onto a receiver component 3 of said sensitive components of the optical sensor 100; 100'; 100A to shield the receiver component from external light radiation. In a further embodiment of the method 200, 300, the step of fixing additional lens elements to the electronic board 1 configured to amplify a light radiation emitted by signal LEDs associated with the electronic board 1 is provided.

It is a further object of the present invention an optical sensor 100, 100' for detecting the characteristics of a thread or yarn F fed to a textile machine manufactured by the method of the invention, wherein this optical sensor includes a lens 6, 6' manufactured from a textile ceramic.

It is a further object of the present invention an optical sensor 100, 100' for detecting the characteristics of a thread or yarn F fed to a textile machine, manufactured by the method of the invention, wherein this optical sensor includes a lens 6, 6' manufactured from a textile ceramic of the type transparent to infrared electromagnetic radiation.

It is a further object of the present invention an optical sensor 100, 100' for detecting the characteristics of a thread or yarn F fed to a textile machine manufactured by the method of the invention, wherein this optical sensor includes an electromagnetic shielding element 8 of metal material.

It is a further object of the present invention an optical sensor 100A for detecting the characteristics of a thread or yarn F fed to a textile machine manufactured by the method of the invention, wherein this optical sensor comprises:

- a first metal half-shell 90 applied to a first face 92, 92' of the body 10, 10' of the optical sensor 100, 100' to coat this first face 92, 92';

- a second metal half-shell 91 applied to a second face 93; 93' of the body 10; 10' of the optical sensor 100, 100' opposed to the first face 92, 92' to coat this second face 93, 93'; the first 90 and second 91 metal half-shells are also shaped to at least partially coat the connecting sides 97, 97' of the aforesaid body 10, 10' between the first 92, 92' and second 93, 93' faces.

The manufacturing method 200, 300 of an optical sensor 100, 100', 100A of the present invention has many advantages over known manufacturing methods and achieves its intended purposes.

In particular, the Applicant has verified that the suggested method allows various models of optical sensors for textile industry applications to be manufactured by modifying the characteristics described above with reference to the electronic board 1.

In addition, the sensors are manufactured at significantly lower costs than in the past and with significantly better sealing characteristics.

Indeed, in the most general example of the manufacturing method 200 of the invention, the thermoplastic resin that makes up the body 10, 10' of the sensor 100, 100' encapsulates and seals the electronic board 1 of the sensor module 50 and the at least one portion of electrical cable 5 or the portion of electrical connector 5', allowing a sensor having IP68 degree of protection to be made in a single pass.

A person skilled in the art may make changes and adaptations to the embodiments of the method for manufacturing an optical sensor for textile applications of the invention or can replace elements with others which are functionally equivalent to satisfy contingent needs without departing from the scope of protection of the following claims. All of the features described above as belonging to a possible embodiment may be implemented independently of the other embodiments described.