Device For Generating A Dielectric Barrier Discharge And Method For Treating An Object To Be Activated

Abstract

The present invention relates to a device for generating a dielectric barrier discharge for treatment of an object (1) to be activated with non-thermal atmospheric pressure plasma, comprising a dielectric working chamber (2) which has a wall (3) of a dielectric material and which encloses a working space (4), wherein a metallization (6) is applied to an outer side (5) of the wall (3) facing away from the working space (4), wherein the working space (4) is an open volume, and a high-voltage source (9) which is configured to apply a high voltage to the metallization (6) or to the object (1) to be activated when the object (1) to be activated is in the working space (4). According to a further aspect, the invention relates to a method of treatment of an object (1) to be activated with a non-thermal atmospheric pressure plasma.

Claims

1-20. (canceled)

21. A device for generating a dielectric barrier discharge for the treatment of an object to be activated with non-thermal atmospheric pressure plasma, comprising a dielectric working chamber having a wall made of a dielectric material and enclosing a working space, the wall having an outer side facing away from the working space, the outer side having metallization, the working space being an open volume; and a high-voltage source which is configured to apply a high voltage to the metallization or to the object to be activated when the object to be activated is arranged in the working space.

22. The device according to claim 21, further including a receptacle that is configured to receive the object to be activated and to move the object into the working space.

23. The device according to claim 22, wherein the receptacle is configured to move the object to be activated in the working space in a rotational movement and/or in a translational movement.

24. The device according to claim 21, wherein the object to be activated is an implant treated with non-thermal atmospheric pressure plasma prior to a medical treatment.

25. The device according to claim 21, wherein the high voltage source is configured to generate a dielectric barrier discharge between the object to be activated and the metallization.

26. The device according to claim 21, wherein atmospheric pressure is present in the working space, or wherein a pressure lower than 1 Atm is present in the working space.

27. The device according to claim 21, wherein the device is configured to hydrophilize a surface of the object to be activated by the treatment with non-thermal atmospheric pressure plasma.

28. The device according to claim 21, further comprising a base unit having an opening for receiving the dielectric working chamber.

29. The device according to claim 28, wherein the dielectric working chamber is adapted to be inserted into the opening of the base unit before the plasma treatment and to be removed from the opening of the base unit after the plasma treatment has been performed.

30. The device according to claim 28, wherein the high voltage source is arranged in the base unit.

31. The device according to claim 21, wherein the wall of the dielectric working chamber has a part located at an entrance of the dielectric working chamber and having a larger thickness than other parts of the wall.

32. The device according to claim 21, wherein the metallization is a continuous sleeve-shaped metallization or comprises several annular sections separated from each other.

33. The device according to claim 21, wherein the high voltage source comprises a piezoelectric transformer.

34. The device according to claim 21, further comprising a fan and/or a filter.

35. The device according to claim 21, wherein the working space is filled with air.

36. The device according to claim 21, wherein the dielectric working chamber is a replaceable disposable article.

37. The device according to claim 21, wherein an inner diameter of the wall of the dielectric working chamber is in the range of 4 mm to 7 mm.

38. The device according to claim 21, further comprising a plurality of high voltage sources.

39. A method of treating an object to be activated with a non-thermal atmospheric pressure plasma, comprising: removing a dielectric working chamber from a sterile package, the dielectric working chamber having a wall made of a dielectric material that encloses a working space, the wall having an outer side facing away from the working space, the outer side having metallization; inserting the dielectric working chamber into an opening of a base unit, the base unit having a high-voltage source; introducing the object to be activated into the working space; and applying a high voltage to the object to be activated or to the metallization so as to generate a dielectric plasma discharge between the object and the metallization.

40. The method according to claim 39, wherein the method takes less than 90 seconds.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In the following, the present invention will be explained with reference to the accompanying figures.

[0041] FIG. 1 schematically shows a device for generating a dielectric barrier discharge.

[0042] FIG. 2 shows the device shown in FIG. 1 in greater detail.

[0043] FIG. 3 shows a dielectric working chamber in a sterile package.

[0044] FIG. 4 shows an alternative embodiment of a dielectric working chamber.

[0045] FIG. 5 shows another alternative embodiment of a dielectric working chamber.

[0046] FIG. 6 shows an alternative embodiment of the device for generating a dielectric barrier discharge.

[0047] FIG. 7 shows another alternative embodiment of the device for generating a dielectric barrier discharge.

[0048] FIG. 8 shows yet another alternative embodiment of the device for generating a dielectric barrier discharge.

[0049] FIG. 9 shows a further alternative embodiment of the device for generating a dielectric barrier discharge.

[0050] FIG. 10 shows a further alternative embodiment of a dielectric working chamber.

DETAILED DESCRIPTION OF THE DRAWINGS

[0051] FIG. 1 schematically shows a device for generating a dielectric barrier discharge, which is configured to treat an object 1 to be activated with a non-thermal atmospheric pressure plasma. The object 1 to be activated is an implant configured to be inserted in a human or animal body. In particular, it is a dental implant. However, the device is also configured to treat other objects with the non-thermal atmospheric pressure plasma. For example, the object 1 to be activated may be made of titanium, in particular grade 4 titanium, or zirconium oxide. Both materials are common for implants. Alternatively or complementarily, the object 1 to be treated may comprise a metal, a plastic or a ceramic.

[0052] The treatment with non-thermal atmospheric pressure plasma hydrophilises the surface of the object 1. It is known that a healing time of an implant is substantially shortened and that its ingrowth behaviour (osseointegration) is substantially improved if the surface of the implant is hydrophilic. In addition, the healing process exhibits increased stability with hydrophilic objects.

[0053] Pure titanium surfaces are hydrophilic and can therefore be wetted very well with water or blood. However, organic impurities can make the surface hydrophobic. Such impurities can occur, for example, during the manufacture or storage of the implant. By treating the implant in the device shown in FIG. 1, it can be ensured that the surface is hydrophilic immediately before inserting the implant into a body. Good wettability of the implant with blood leads to a short healing time and stabilises the healing process.

[0054] The device has a dielectric working chamber 2. The dielectric working chamber 2 has a wall 3 made of a dielectric material which encloses a working space 4. The working space 4 is an open volume. In the embodiment example shown in FIG. 1, the wall 3 is sleeve-shaped. The dielectric working chamber 2 has an entrance 2a, through which the object 1 to be treated can be introduced into the working space 4, and an exit 2b. The exit 2b is opposite the entrance 2a. An air stream can flow through the working space 4 from the entrance 2a to the exit 2b.

[0055] The material of the wall 3 is chemically inert, so that chemical contamination of the object 1 to be activated is avoided during the plasma treatment. For example, the wall 3 may comprise a quartz, a glass or aluminium oxide.

[0056] A thickness D of the wall 3 is between 0.5 mm and 3.0 mm, preferably between 1.0 mm and 2.0 mm. For example, the thickness D of the wall may be 1.5 mm. Such thicknesses D of the wall 3 allow the wall 3 to act as a dielectric barrier during plasma discharge. The thickness D indicates the distance between an inner side 7 of the wall 3 and an outer side 5 of the wall 3.

[0057] The wall 3 encloses the working space 4. Atmospheric pressure may be present in the working space 4. It is not necessary in the device to lower the pressure in the working space 4 to a low pressure before the plasma treatment. However, in alternative embodiments of the device, the pressure in the working space 4 can be lowered so that a pressure of less than one atmosphere is present in the working space 4.

[0058] The working space 4 is filled with air. In an alternative embodiment example, the working space 4 is filled with another process gas.

[0059] An outer side 5 of the wall facing away from the working space 4 may be partially or completely coated with a metallization 6. The metallization 6 forms an electrode. The metallization 6 consists of an electrically conductive material, for example copper or silver. The metallization 6 can be sputtered on or electroplated. Further possibilities for applying the metallization 6 are the use of an adhesive foil, a metal hose pressed onto the tube or a conductive spray lacquer.

[0060] The metallization 6 completely surrounds the cylindrical wall 3 along the outer circumference of the wall 3. The length L of the metallization 6 indicates the extension of the metallization 6 in a longitudinal direction. The longitudinal direction runs along the axis of symmetry of the cylindrical wall 3 of the dielectric working chamber.

[0061] The length L of the metallization 6 should be adapted to the length of the object 1 to be treated. The length L of the metallization 6 can be between 10 mm and 30 mm. For example, a length of the metallization 6 of 20 mm can be chosen. Metallizations 6 with such lengths L are sufficient to completely enclose common dental implants and thus ensure that the entire implant is treated at the same time. The metallization 6 can also be longer, as plasma ignitions only occur between the electrode and the implant. Alternatively, the length L of the metallization 6 can also be chosen to be significantly smaller than the length of the object 1 to be treated. In this case, the object 1 to be treated must be moved in the longitudinal direction relative to the metallization 6 in such a way that it is ensured that the object 1 is completely treated with plasma.

[0062] In the embodiment example shown in FIG. 1, the metallization 6 is connected to a high-voltage source 9 via a contact 8. The high-voltage source 9 is configured to generate a high voltage and apply it to the metallization 6. For example, the high-voltage source 9 can be a piezoelectric transformer. A high voltage generated in the output area of the piezoelectric transformer is tapped off and applied to the metallization 6 via the contact 8. Alternative high-voltage sources 9 providing a high-voltage alternating voltage can also be used.

[0063] Furthermore, the device has a receptacle 10 which is configured to grip the object 1 to be treated and introduce it into the working space 4. The object 1 to be treated is connected to a reference potential, in particular a ground potential, via the receptacle 10. The receptacle 10 is configured to introduce the object 1 to be treated into the working space 4 in a linear movement. Furthermore, the receptacle 10 can be configured to move the object 1 to be treated in a linear movement within the working space 4. For example, this may be an up and down movement. Furthermore, the receptacle 10 is configured to rotate the object 1 to be treated in a rotational movement within the working space 4. The linear and rotational movement of the object 1 to be treated within the working space 4 can ensure that the surface of the object 1 to be treated is evenly treated with the plasma.

[0064] The object 1 to be treated, to which a reference potential is applied via the receptacle 10, acts as a counter-electrode during the plasma discharge, the electrode being formed by the metallization 6 of the wall 3. The wall 3 acts as a dielectric barrier between the metallization 6 and the object 1 to be treated. Plasma ignition thus occurs by dielectric barrier discharge, in which the plasma is generated directly on the surface of the object 1 to be treated.

[0065] The receptacle 10 can be a tool which is either moved by hand or which is connected to a mechanical drive. It can also be, for example, a torque ratchet or a spanner.

[0066] FIG. 2 shows the device shown in FIG. 1 in greater detail. The device further comprises a base unit 11 with a housing 12 in which the dielectric working chamber 2 is inserted. The dielectric working chamber 2 is designed as a sterile exchange unit. It is inserted into the housing 12 immediately before the plasma treatment. The base unit 11 has an opening into which the dielectric working chamber 2 is inserted.

[0067] The base unit 11 contains the high-voltage source 9 and possibly other elements. A control unit 13 for controlling the high-voltage source 9 is arranged in the base unit 11. The control unit 13 has interfaces for interaction with a user. For example, the control unit 13 has a display and function keys. Further, the base unit 11 may comprise a fan 14. The fan 14 can provide a constant flow of air through the working chamber 2. This can ensure that the object 1 to be treated is cooled by the air flow and is not heated too much during the plasma treatment. Furthermore, the base unit 11 may comprise a filter 15 arranged between the dielectric working chamber 2 and an air outlet of the fan 14. The filter 15 may in particular be configured to filter out ozone. Ozone is produced as a by-product during plasma treatment and can be harmful to health if the concentration is too high. The addition of the ozone filter 15 can ensure that excessive ozone concentrations cannot occur outside the housing 12.

[0068] The base unit 11 permanently houses the components of the device that do not need to be replaced after each plasma treatment of an object 1 to be activated. These include the high-voltage source 9, the control unit 13, the fan 14 and the filter 15.

[0069] Immediately before the plasma treatment, the dielectric working chamber 2 is inserted into the base unit 11. When the dielectric working chamber 2 is inserted into the opening of the base unit 11, the dielectric working chamber 2 is arranged in such a way that the metallization 6 is electrically contacted with the high voltage supply 9, so that the high voltage supply 9 applies a high voltage to the metallization 6. When the dielectric working chamber 2 is inserted into the base unit 11, the metallization 6 is connected to the contact 8.

[0070] Subsequently, the object 1 to be treated can be introduced into the working space 4 by means of the receptacle 10. For this purpose, the object 1 to be treated is gripped by the receptacle 10 and inserted through the entrance 2a of the dielectric working chamber 2. Now the plasma treatment begins, whereby the object 1 to be treated is moved during the plasma treatment by means of the receptacle 10. The plasma treatment lasts less than 90 seconds, preferably less than 60 seconds, in particular less than 30 seconds.

[0071] After the plasma treatment, first the object 1 to be activated and then the dielectric working chamber 2 are removed from the base unit 11. After the end of the plasma treatment, the object 1 to be activated can be removed from the dielectric working chamber 2 and, for example, the medical treatment can be started immediately with the step of inserting the implant. Intermediate storage of the object 1 to be treated is not necessary. Due to the short duration of the plasma treatment, the plasma treatment can be carried out immediately before the medical treatment of inserting the implant.

[0072] The wall of the dielectric working chamber 2 has a part 16 in the part of the entrance 2a, the thickness of which is higher than the thickness of the wall 3 in the remaining part of the dielectric working chamber 2. Due to the increased thickness, the part 16 forms a collar of the dielectric working chamber 2. The part 16 forms a support which rests on the housing 12 when the dielectric working chamber 2 is arranged in the opening of the base unit 11. In this way, the dielectric working chamber 2 can be stably positioned on the base unit 11. This ensures that the dielectric working chamber 2 is arranged in a defined position. Furthermore, the part 16 of the increased thickness serves as a support for the receptacle 10 when an object 1 to be activated is inserted from the receptacle 10 into the dielectric chamber 2. Thus, the object 1 to be activated is arranged in a defined position within the working space 4. The part 16 of increased thickness also provides insulation between the metallization 6 and the receptacle 10. Furthermore, the part 16 of increased thickness provides a seal to the housing 12 so that little ozone escapes from the opening of the housing 12 into which the electrical working chamber 2 is inserted.

[0073] FIG. 3 shows the dielectric working chamber 2 in a sterile package 17. The dielectric working chamber 2 is only used once during the plasma treatment and is to be disposed of after the plasma treatment has been carried out. Before the next plasma treatment, a new dielectric working chamber 2 is to be inserted into the base unit 11. In this way it is possible to avoid cleaning the high voltage source 9, which would be very complex. Immediately before insertion into the base unit 11, the dielectric working chamber 2 is removed from the sterile packaging 17. This ensures that the dielectric working chamber 2 is not contaminated.

[0074] FIG. 4 shows an alternative embodiment of the dielectric working chamber 2. In the alternative embodiment shown in FIG. 4, the wall 3 additionally has a bottom 18 which closes the exit of the working chamber. This dielectric working chamber can also be inserted into the housing.

[0075] FIG. 5 shows another alternative embodiment of the dielectric working chamber 2. In the embodiment shown in FIG. 5, an active substance 19 is additionally arranged on the bottom of the working chamber 2. The active substance 19 can be a process gas or a liquid. If the active substance 19 is supplied at a given vapour pressure during a dielectric barrier discharge, new species can be formed in the gas phase which have a strongly oxidising character or which have a reducing character, or chemically reactive fragments can be released, whereby rough glass-like layers can be formed on the object to be activated. For example, the active substance 19 may comprise water or hydrogen peroxide, which may cause oxidation during the dielectric barrier discharge. Alternatively or additionally, the active substance 19 may comprise hydrogen, which has a reducing effect during the dielectric barrier discharge. Alternatively or additionally, the active substance 19 may be HMDSO or TEOS organosilicon compound applied by PECVD (plasma enhanced chemical vapor deposition), which release chemically reactive fragments.

[0076] The metallization 6 has an outwardly projecting protrusion 6a which allows the metallization 6 to be contacted. Further, the metallization 6 is covered by an insulation 6b, wherein the protrusion 6a protrudes from the insulation 6b and thus remains free of the insulation 6b. The insulation 6b protects the metallization 6. The protrusion 6a enables contacting of the metallization 6 despite the insulation 6b. The working chambers 2 shown in the previous figures may also have a metallization 6 with the protrusion 6a projecting outwards and the insulation 6b.

[0077] FIG. 6 shows an alternative embodiment of the device. In the embodiment example shown in FIG. 6, the high voltage source 9, in this case a piezoelectric transformer, is not directly connected to the metallization 6 on the dielectric working chamber 2 via a line or contact 8. Instead, the energy transfer between the high-voltage source 9 and the metallization 6 takes place without contact, e.g. via a discharge or a spark gap.

[0078] FIG. 7 shows another alternative embodiment. In the example shown in FIG. 7, the high-voltage source 9 is not connected to the metallization 6 on the dielectric working chamber 2, but to the object 1 to be treated. Accordingly, a high voltage is applied to the object 1 to be treated. The metallization 6 on the dielectric working chamber 2 is connected to the reference potential. Just as in the previous embodiments, a dielectric discharge and plasma ignition occur due to the potential difference between the surface of the object 1 to be treated and the metallization 6. The wall 3 of the dielectric working chamber 2 also acts here as a dielectric barrier.

[0079] FIG. 8 shows a further example of an embodiment. In the example shown in FIG. 8, several, for example three, piezoelectric transformers are arranged around the dielectric working chamber 2 as high-voltage sources 9. The piezoelectric transformers are operated openly, i.e. the energy is transferred via a spark gap or a discharge, as also shown in FIG. 5. By using several high-voltage sources 9, the energy loss that inevitably occurs with contactless energy transmission can be compensated. The object 1 to be activated is rotated in the working space 4 during the plasma treatment.

[0080] FIG. 9 shows another alternative embodiment in which a first high-voltage source 9, which is a piezoelectric transformer, is arranged on one longitudinal side of the working chamber 2 and transmits energy to the metallization 6 without contact. Furthermore, a second high-voltage source, in particular a second piezoelectric transformer, is arranged under the bottom 18 of the dielectric working chamber 2. A metallization 6 is applied to the outer side of the bottom 18, which faces away from the working space 4, and the piezoelectric transformer transmits a high voltage 9 to this. This results in a plasma ignition between the bottom 18 and the object 1 to be activated. The energy transmission between the second high-voltage source 9 and the metallization 6 of the bottom 18 takes place without contact, i.e. via a discharge or a spark gap. Alternatively, the second high-voltage source 9 could be electrically connected to the metallization 6 via a contact 8.

[0081] FIG. 10 shows a further embodiment of the dielectric working chamber 2. In the embodiment shown in FIG. 10, the metallization 6 is not continuous, but consists of several ring-shaped metallizations 6 separated from each other. Each ring of the metallizations 6 can, for example, have a length in a range of 1 mm to 3 mm, whereby between two rings in each case an area with an extension in the longitudinal direction of between 0.5 mm and 2.0 mm is arranged free of a metallization 6.

[0082] The ring-shaped design of the metallization 6 leads to a reduction of the capacitance, whereby a parasitic load decreases. As a result, the power consumption of the device is reduced and less reactive currents flow. Furthermore, the field strength at the edges of the rings is particularly high, which enables a particularly efficient plasma treatment. Alternatively, only a single ring could be used as metallization 6 and the object 1 to be treated could be moved sufficiently in the longitudinal direction to ensure that it is treated over its entire surface.

LIST OF REFERENCE SIGNS

[0083] 1 object to be activated/implant

[0084] 2 Dielectric working chamber

[0085] 2a entrance

[0086] 2b Exit

[0087] 3 wall

[0088] 4 working space

[0089] 5 outer side

[0090] 6 Metallization

[0091] 6a Protrusion

[0092] 6b Insulation

[0093] 7 Inner side

[0094] 8 Contact

[0095] 9 High voltage source

[0096] 10 Receptacle

[0097] 11 Base unit

[0098] 12 Housing

[0099] 13 Control unit

[0100] 14 Fan

[0101] 15 Filter

[0102] 16 Part/collar

[0103] 17 Packing

[0104] 18 Bottom

[0105] 19 Active substance

[0106] D Thickness of wall

[0107] L Length of metallization