Method and device for reading out at least one code element on at least one plastic container

Abstract

The invention relates to a method (100) for reading out at least one code element (14) of at least one plastic container (10), the code element (14) having been produced on the plastic container (10) by means of a laser device (42) and having material of the plastic container (10), and the method (100) comprising at least the following steps: irradiating (102) the code element (14) on a plastic container (10) with first radiation (20), which has a first wavelength, from a first direction (22); sensing (104) second radiation (24) which has a second wavelength and which is emitted by the code element (14) at least in a second direction (26) after the first radiation (20) has been absorbed, the second wavelength being different from the first wavelength, and the first direction (22) and the second direction (26) having an intersection point at the code element (14); and reading out (106) the code element (14) by means of the sensed second radiation (24). Thus, a method (100) for reading out at least one code element (14) is provided in which code elements (14) can be read when there is a dark background and the probability of damage to the code elements (14) is reduced.

Description

[0001] Method and device for reading at least one code element of at least one plastic container

[0002] The invention relates to a method and a device for reading at least one code element of at least one plastic container.

[0003] Containers can be coded for various reasons. In particular, code features can be applied to containers to ensure clear identification, for example, in the case of defective goods. Furthermore, manufacturing, filling, and / or best-before dates can be coded on the containers.

[0004] For example, EP 0 531 735 A1 discloses laser engraving of code features onto plastic containers. The code features can include numbers and / or letters and / or a machine-readable code, such as a barcode.

[0005] However, the readability of the engraved code features may be impaired, especially if the plastic containers are made of a transparent material and filled with a dark product.

[0006] Furthermore, DE 10 2020 131 365 A1 discloses applying code features to a container with a fluorescent coating, for example, using a special ink. The coating fluoresces under ultraviolet light.

[0007] Here, the coating can be damaged, so that the code feature can no longer be fully read.

[0008] The object of the invention is to provide a method and a device for reading at least one code element, in which code elements are readable against a dark background and the probability of damage to the code elements is reduced. This object is achieved by the features of the independent claims. Advantageous further developments are the subject of the dependent claims and the following description.

[0009] According to a first aspect of the invention, a method is provided for reading at least one code element of at least one plastic container, wherein the code element was generated on the plastic container by means of a laser device and comprises material of the plastic container, wherein the method comprises at least the following steps: irradiating the code element of a plastic container with a first radiation having a first wavelength from a first direction; detecting a second radiation having a second wavelength and emitted by the code element after absorption of the first radiation at least in a second direction, wherein the second wavelength differs from the first wavelength, wherein the first direction and the second direction have an intersection point at the code element; and reading the code element by means of the detected second radiation.

[0010] The invention is based on the finding that the plastic material of the container has an increased absorption rate for electromagnetic radiation, for example ultraviolet radiation, as a result of treatment with a laser. The plastic material can emit the absorbed radiation at a longer wavelength. This can result in luminescence, in particular phosphorescence and / or fluorescence, of the material. Due to the increased absorption rate of the plastic material that forms the code element, the intensity of the luminescence of the material at the code element is also higher than in the surroundings of the code element. As a result, the material of the code element glows brighter than the surrounding material. In particular, with transparent materials where the laser-engraved code elements have a low contrast without luminescence, the visibility of the code element can be increased using the method.

[0011] Even when the container is filled with a dark product, the code element can be detected and identified by the luminescence. The direction of the first radiation can be at a different angle to the plastic container than at least one beam direction of the second radiation. For example, the first radiation can be directed at the code element at a flat beam angle, for example in the case of grazing illumination. The second radiation can be detected at a steep beam angle in order to read the code element. The grazing incidence of the first radiation maximizes the path of the first radiation in the plastic material of a container, which usually has a thin wall. This allows the amount of absorbed radiation to be increased, so that the intensity of the radiation from the luminescence can also be increased.In addition, different first radiations at different angles can lead to additional fluorescence and a maximized signal due to varying surface normals of the code element.

[0012] This process makes it possible to make code elements visible regardless of the transparency of the material or the inserted contents. Furthermore, the code elements are still integrated into the container material, reducing the likelihood of damage to the basic elements or preventing them altogether without destroying the container.

[0013] According to some embodiments, it is conceivable that the second wavelength may be part of the visible spectral range, preferably in the range between 380 nm and 500 nm, more preferably between 400 nm and 450 nm.

[0014] This allows optical detection methods to be used to read the code element.

[0015] According to some embodiments, it is conceivable that the first wavelength may be part of the ultraviolet spectral range.

[0016] By using ultraviolet radiation with higher photon energy than, for example, visible light in the visible wavelength range as the first radiation, luminescence or fluorescence can be induced in a controlled manner, with the ultraviolet radiation being uncritical in its handling. According to some embodiments, it is conceivable that the code element could consist of a polyethylene terephthalate (PET) material that has been treated by the laser device.

[0017] For example, the PET material fluoresces when exposed to ultraviolet radiation in a visible spectral range.

[0018] According to some embodiments, it is conceivable that an angle of incidence of the first radiation, which the first direction includes with a surface of the plastic container, at the code element can be in an angular range greater than 0° and less than 90°, preferably between 1° and 45°, more preferably between 2° and 10°.

[0019] Most preferred is a grazing incidence of the first radiation on the surface of the code element. This means that the surface of the element and the first direction of the first radiation form an acute angle between them.

[0020] According to some embodiments, it is conceivable that the at least one plastic container can be filled with at least one filling material before the code element is irradiated with the first radiation.

[0021] The reading of the code element in the process explained above for transparent container materials can also take place after filling and regardless of the color of the contents.

[0022] In a second aspect, the invention relates to a device for reading at least one code element of at least one plastic container, wherein the code element was generated on the plastic container by means of a laser and comprises material of the plastic container, wherein the device has at least one receiving area for receiving at least one plastic container, at least one irradiation device for emitting a first radiation with a first wavelength into the receiving area, and at least one detection device for detecting a second radiation with a second wavelength, which is emitted by a plastic container arranged in the receiving area, wherein it is provided according to the invention that the irradiation device is aligned such that the first radiation radiates in a first direction into the receiving area, and the detection device is aligned such thatthat it detects the second radiation from a second direction, wherein the first direction and the second direction have an intersection point at the code element of a plastic container arranged in the receiving area.

[0023] According to some embodiments, it is conceivable that an angle of incidence of the first radiation, which the first direction includes with a surface of the plastic container, at the code element can be in an angular range greater than 0° and less than 90°, preferably between 1° and 45°, more preferably between 2° and 10°.

[0024] Advantages and effects, as well as further developments of the device, arise from the advantages and effects, as well as further developments of the method described above. To avoid repetition, reference is made to the preceding description in this regard.

[0025] In a third aspect, the invention relates to a system for producing and / or treating at least one plastic container, comprising at least one treatment device for at least one plastic container, at least one transport device and at least one device according to the preceding description, wherein the treatment device has a laser device which is designed to generate at least one code element on a plastic container by laser irradiation, wherein the transport device is designed to transport the at least one treated plastic container from the treatment device to the receiving area of ​​the device.

[0026] According to some embodiments, it is conceivable that the system may further comprise at least one filling device for filling at least one plastic container, which may be arranged in front of the device in a transport direction of the plastic containers.

[0027] Advantages and effects, as well as further developments of the system, arise from the advantages and effects, as well as further developments of the device and method described above. To avoid repetition, reference is therefore made to the previous description in this regard.

[0028] The invention is described below using an exemplary embodiment with reference to the accompanying drawings. They show:

[0029] Figure 1 shows a flowchart of the method for reading at least one code element of at least one plastic container;

[0030] Figure 2 is a schematic representation of a plastic container;

[0031] Figure 3 is a schematic representation of a device for reading at least one code element; and

[0032] Figure 4 is a schematic representation of a plant for producing and / or treating at least one plastic container.

[0033] The method for reading at least one code element of at least one plastic container is explained in more detail using the flowchart in Figure 1. The entire method is designated by reference symbol 100.

[0034] The method 100 can be carried out on a container 10, which is shown in Figure 2 as a bottle with a surface 12 and a code element 14. The container 10 can be filled with a filling material 11. The plastic container 10 can be made of a PET material. Furthermore, the code element 14 can be introduced into the plastic material of the container 10 by a laser device. According to a step 102 in the method 100, the code element 14 of the plastic container 10 is irradiated with a first radiation 20. The first radiation 20 has a first wavelength. Furthermore, the first radiation 20 is radiated onto the plastic container 10 from a first direction 22.

[0035] The angle of incidence of the first radiation 20 can result from a beam direction of the first radiation 20, in particular from the first direction 22, which strikes the code element 14. The angle of incidence can be included and measured between the first direction 22 and the surface 12 of the container 10. The angle of incidence of the first radiation 20 can, for example, lie in an angular range between 0° and 90°, whereby 0° and 90° can be excluded. The angle of incidence is preferably in a range between 1° and 45°, more preferably between 2° and 10°, so that the code element 14 is illuminated in a grazing manner by the first radiation 20.

[0036] The wavelength of the first radiation 20 may be in the ultraviolet range, ie for example between 100 nm and 380 nm, preferably between 315 nm and 380 nm.

[0037] The irradiation can excite the PET material to luminesce at a longer wavelength and thus emit second radiation 24. The second radiation 24 has a second wavelength that can be in a wavelength range between 380 nm and 500 nm, whereby 380 nm can be excluded, and preferably lies between 400 nm and 450 nm. This means that PET material can exhibit fluorescent properties when irradiated with a first radiation 20 from the ultraviolet range.

[0038] In a further step 104, the second radiation 24 is detected. The second radiation 24 can be emitted in a second direction 26 from the code element 14. The first direction 22 and the second direction 26 then intersect at the code element 14. This means that the first direction 22 and the second direction 26 preferably do not run parallel to one another. The detection of the second radiation 24 can be carried out, for example, using a detection device. If the second radiation 24 has a wavelength in the optical spectral range, the detection device can be, for example, an optical camera.

[0039] For example, using image processing methods, the code element 14 can be identified and thus read out in a further step 106 using the detected second radiation 24. In this way, for example, characters represented by the code element 14 can be recognized by the image processing.

[0040] In this case, before the steps 102 to 106 explained above, the container 10 can first be filled with a filling material 11 in an optional step 108. The filling material 11 can have a dark color. In particular, if the material of the plastic container 10 is transparent, the entire plastic container 10 has a dark color after being filled with a dark filling material 11. The code element 14 in the transparent material can therefore have very low contrast and be difficult or impossible to detect under normal optical conditions. The steps explained above cause the code element 14 to glow, so that the contrast is increased again and the code element 14 can be deciphered.

[0041] The detection of the second radiation 24 in step 104 can alternatively be carried out by a user, who can then read the code element 14 in this way.

[0042] In one embodiment, the method 100 can be carried out using the device 28 shown in Figure 3. The device 28 is designed to read the at least one code element 14 of at least one plastic container 10. The device 28 has a receiving area 13 in which a plastic container 10 can be received. The plastic container 10 can thus be arranged in the receiving area 13 so that the code element 14 of the plastic container 10 can be read. The device 28 also has at least one irradiation device 16 that can emit first radiation 20 into the receiving area 13. The plastic container 10 can be arranged such that the first direction 22 of the first radiation 20 is oriented such that it has a grazing incidence on the code element 14.The angle of incidence can be in a range greater than 0° and less than 90°, preferably between 1° and 45°, more preferably between 2° and 10°.

[0043] The material of the code element 14 can be excited by the absorption of the first radiation 20 and emit second radiation 24.

[0044] A detection device 18 of the device 28 can detect second radiation 24 emitted by the code element 14. The detection device 18 is arranged such that it can detect second radiation 24 emanating from the code element 14 from a second direction 26. The first direction 22 and the second direction 26 have an intersection point at the code element 14. Furthermore, the first direction 22 can be oriented such that a grazing incidence of the first radiation 20 occurs on the code element 14. The second direction 26 can be oriented such that the detection device 18 is directed frontally onto the code element 14.

[0045] Figure 4 shows a system 30 for producing and / or treating at least one plastic container 10. The system 30 comprises at least one treatment device 36, at least one transport device 32, 34, 38, and at least one device 28 according to the above explanations.

[0046] The at least one treatment device 36 can be configured to treat at least one container 10 using a laser device 42. The laser device 42 can create a code element 14 on a plastic container 10 by laser irradiation. The laser irradiation can be used to engrave the material of the plastic container, for example, by heating, or to modify a crystal structure of the material in the wall of the plastic container.

[0047] This increases the absorption rate for at least part of the electromagnetic radiation spectrum. Especially if the plastic container is made of PET material, the absorption of ultraviolet radiation can be increased by the change caused by the laser. The result is that the PET material exhibits an increased intensity of luminescence, in this case, fluorescence, at the treated location due to the increased absorption of ultraviolet radiation.

[0048] The transport device 32, 34, 38 can transport at least one plastic container 10. In the illustrated example, the transport device can have an ejection path 38 that transports plastic containers 10 ejected by an ejection device 40 to the device 28. The ejection device 40 can, for example, eject defective plastic containers 10.

[0049] In general, the transport device 32, 34, 38 can transport at least one plastic container 10 from the treatment device 36 to the receiving area 13. For this purpose, the transport device 32, 34, 38 can have at least one transport wheel, which can be mounted for rotation about a vertical axis and can have transport elements on its circumference for transporting one plastic container 10 each.

[0050] The containers 10 are transported along a transport direction 46.

[0051] In the transport direction 36 in front of the device 28, the system 30 can have a filling device 44 in which the plastic containers 10 can be filled with a filling material 11.

[0052] The example described above does not limit the invention in any way. Rather, the invention can be modified in many ways. All of the features of the invention described above can be essential to the invention alone or in combination with one another. List of reference symbols

[0053] 10 plastic containers

[0054] 11 Filling material

[0055] 12 Surface

[0056] 13 Recording area

[0057] 14 Code element

[0058] 16 Irradiation facility

[0059] 18 Recording device

[0060] 20 first radiation

[0061] 22 first direction

[0062] 24 second radiation

[0063] 26 second direction

[0064] 28 Device

[0065] 30 Appendix

[0066] 32 Transport device

[0067] 34 Transport device

[0068] 36 Treatment device

[0069] 38 Transport device

[0070] 40 Ejection device

[0071] 42 Laser device

[0072] 44 Filling device

[0073] 46 Transport direction

Claims

Claims 1 . Method (100) for reading at least one code element (14) of at least one plastic container (10), wherein the code element (14) was generated on the plastic container (10) by means of a laser device (42) and comprises material of the plastic container (10), wherein the method (100) comprises at least the following steps: Irradiating (102) the code element (14) of a plastic container (10) with a first radiation (20) having a first wavelength from a first direction (22); Detecting (104) a second radiation (24) having a second wavelength and emitted by the code element (14) after absorption of the first radiation (20) at least in a second direction (26), wherein the second wavelength differs from the first wavelength, wherein the first direction (22) and the second direction (26) have an intersection point at the code element (14); and Reading (106) the code element (14) by means of the detected second radiation (24).

2. Method (100) according to claim 1, characterized in that the second wavelength is part of the visible spectral range, preferably in the range between 380 nm and 500 nm, more preferably between 400 nm and 450 nm.

3. Method (100) according to one of the preceding claims 1 or 2, characterized in that the first wavelength is part of the ultraviolet spectral range.

4. Method (100) according to one of the preceding claims, characterized in that the code element (14) consists of a polyethylene terephthalate material which has been treated by the laser device (42).

5. Method (100) according to one of the preceding claims, characterized in that an angle of incidence of the first radiation (20), which the first direction (22) includes with a surface (12) of the plastic container (10), at the code element (14) lies in an angular range greater than 0° and less than 90°, preferably between 1° and 45°, more preferably between 2° and 10°.

6. Method (100) according to one of the preceding claims, characterized in that the at least one plastic container (10) is filled (108) with at least one filling material (11) before the code element (14) is irradiated with the first radiation (20).

7. Device (28) for reading at least one code element (14) of at least one plastic container (10), wherein the code element (14) was generated by means of a laser on the plastic container (10) and comprises material of the plastic container (10), wherein the device (28) has at least one receiving area (13) for receiving at least one plastic container (10), at least one irradiation device (16) for emitting a first radiation (20) with a first wavelength into the receiving area (13), and at least one detection device (18) for detecting a second radiation (24) with a second wavelength, which is emitted by a plastic container (10) arranged in the receiving area (13), characterized in that the irradiation device is aligned such that the first radiation (20) is directed in a first direction (22) into the receiving area (13), and the detection device is aligned such that it detects the second radiation (24) from a second direction (26), wherein the first direction (22) and the second direction (26) have an intersection point at the code element (14) of a plastic container (10) arranged in the receiving area (13).

8. Device (28) according to claim 7, characterized in that an angle of incidence of the first radiation (20), which the first direction (22) includes with a surface (12) of the plastic container (10), at the code element (14) lies in an angular range greater than 0° and less than 90°, preferably between 1° and 45°, more preferably between 2° and 10°.

9. System (30) for producing and / or treating at least one plastic container (10), comprising at least one treatment device (36) for at least one plastic container (10), at least one transport device (32, 34, 38) and at least one device (28) according to one of claims 7 or 8, wherein the treatment device (36) has a laser device (42) which is designed to generate at least one code element (14) on a plastic container (10) by laser irradiation, wherein the transport device (32, 34, 38) is designed to transport the at least one treated plastic container (10) from the treatment device (36) to the receiving area (13) of the device (28).

10. Plant (30) according to claim 9, characterized in that the plant (30) further comprises at least one filling device (44) for filling at least one plastic container (10), which is arranged in front of the device (28) in a transport direction (46) of the plastic containers (10).

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