Coating system comprising ZrO2 for electrosurgical devices

Abstract

A coating system comprising at least one layer made at least essentially of ZrO.sub.2 which is used for providing insulating properties to parts of medical devices, particularly of electrosurgical devices.

Claims

1. A coating system having electrically insulating properties deposited on a surface of an electrically conductive substrate which is a part of a medical device, particularly of an electrosurgical device, the coating system comprising: at least one zirconium dioxide layer comprising droplets which consist essentially of zirconium, wherein the droplets are melted material from a target which was not evaporated properly and which consequently did not react properly with reactive oxygen gas for forming ZrO.sub.2, and wherein the at least one zirconium dioxide layer renders the surface of the electrically conductive substrate electrically non-conductive.

2. The coating system according to claim 1, wherein the at least one zirconium dioxide layer exhibits a dielectric constant of about 18.4 and/or high voltage breakdown of about 0.60 kV and/or a breakdown current of about 20 mA.

3. The coating system according to claim 1, wherein a thickness of the at least one zirconium dioxide layer is less than 30 m.

4. The coating system according to claim 3 wherein the thickness of the at least one zirconium dioxide layer is at least 3 m.

5. The coating system according to claim 1, wherein the coating system further comprises at least one zirconium nitride layer.

6. The coating system according to claim 5, wherein the zirconium nitride layer is deposited between the surface of the electrically conductive substrate and the at least one zirconium dioxide layer as an interlayer and/or as a support layer.

7. The coating system according to claim 1, wherein the surface of the electrically conductive substrate is at least a part of a surface of an electrode.

8. The coating system according to claim 1, wherein the electrically conductive substrate is a wire of a guide wire.

9. The coating system according to claim 1, wherein the coating system is deposited on the surface of a medical device selected from the group consisting of a blade, a cutter, an ablator a monopolar electrosurgical instrument, and a bipolar electrosurgical instrument.

10. The coating system according to claim 9, wherein the medical device includes, an electrode formed of a metal wire and at least a tip attached to the wire whereat the electrode offers a contact surface to be in contact with tissue of a patient, and the coating system is deposited on at least a part of a surface of the electrode in such a way that electrical conductivity of the coated electrode surface is reduced and consequently thermal energy at the electrode contact surface is also reduced in order to avoid damages of the tissue.

11. The coating system according to claim 9, wherein the medical device includes a surface of an electrode which can be in contact with a patient body or with a body of an operator of the medical device and the coating system is deposited on at least a part of this surface in order to avoid an electrical shock of the patient or of the operator.

12. The coating system according to claim 9, wherein the coating system is applied to one or more surfaces of the medical device in order to avoid a short of the medical device during operation.

13. The coating system according to claim 9, wherein the medical device is used for cutting tissue and/or for ablating occlusions.

14. A method for forming a coating system, comprising: depositing at least one zirconium dioxide layer comprising droplets consisting essentially of zirconium on a surface of an electrically conductive substrate which is part of a medical device, particularly of an electrosurgical device, using physical vapour deposition techniques including arc evaporation of targets consisting essentially of zirconium in an oxygen-containing atmosphere, and applying a pulsed bias voltage to the surface of the electrically conductive substrate during deposition of the at least one zirconium dioxide layer, wherein the at least one zirconium dioxide layer renders the surface of the electrically conductive substrate electrically non-conductive, and wherein the droplets are melted material from the targets which was not evaporated properly and which consequently did not react properly with reactive oxygen gas for forming ZrO.sub.2.

15. The method according to claim 14, comprising using high power impulse magnetron sputtering techniques to deposit at least one layer on the surface of the electrically conductive substrate.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(1) ZrO.sub.2-containing coating systems according to the present invention can be applied on the surface of parts of medical devices that require electrical insulation, e.g. electrosurgical devices, such as mono- and bipolar surgical instruments.

(2) ZrO.sub.2-containing coating systems according to the present invention are particularly ideal for providing dielectric insulating properties to medical devices and instruments such as blades, cutters and ablators, as well as bipolar and monopolar devices and also medical electronics in general.

(3) ZrO.sub.2-containing coating systems according to the present invention have more reliable properties than heat-shrink tubing and polymer over moulding and are therefore most suitable for coating electrosurgical instruments.

(4) A ZrO.sub.2 layer forming a coating system according to the present invention, or included in a coating system according to the present invention exhibits preferably a dielectric constant of about 18.4 and/or a high voltage breakdown of about 0.60 kV and/or a breakdown current of about 20 mA.

(5) A preferred embodiment of a ZrO.sub.2-containing coating system according to the present invention comprises at least one zirconium nitride layer. Preferably the ZrN-layer is deposited as interlayer and/or support layer between the substrate surface and the ZrO.sub.2-layer.

(6) A preferred method for depositing a ZrO.sub.2 layer according to the present invention involves the use of arc evaporation techniques for evaporating targets (at least one target) made of zirconium or comprising mainly zirconium in a reactive oxygen-containing atmosphere for forming ZrO.sub.2 on the substrate surface. Furthermore, preferably at least during the deposition of the ZrO.sub.2-layer a pulsed bias voltage is applied to the substrate.

(7) A ZrO.sub.2-layer deposited by reactive arc ion plating PVD techniques according to the above mentioned embodiment of a method according to the present invention exhibits droplets containing at least mostly or mainly zirconium. The droplets are melted material from the target which could not be evaporated properly and consequently could not react properly with the reactive gas (in this case oxygen) for forming the desired coating material (in this case ZrO.sub.2). The ZrO.sub.2-layer deposited in this way exhibited a particularly good performance.

(8) In a preferred embodiment of a coating system comprising at least one arc-PVD-deposited ZrO.sub.2-layer according to the present invention the total thickness of the ZrO.sub.2-layer is not greater than 30 nm, preferably not greater than 20 m, more preferably not greater than 10 m.

(9) The thickness of an arc-PVD-deposited ZrO.sub.2-layer for a coating system according to the present invention must be so selected, that the ZrO.sub.2-layer can provide sufficient isolation. For this purpose it is necessary to take into account the surface quality of the surface to be coated and also the porosity of the ZrO.sub.2 coating.

(10) Particularly, very good results were attained in the context of the present invention by producing coating systems which contain at least one arc-PVD-deposited ZrO.sub.2-layer having a thickness of at least 3 m, more particularly of at least 4 m or 5 m.

(11) A further preferred method for depositing a ZrO.sub.2 layer for a coating system according to the present invention involves at least one step in which at least one Zr-target is sputtered by using HIPIMS-techniques in an oxygen-containing atmosphere and by applying a pulsed bias voltage to the substrate which is being coated during the ZrO.sub.2-deposition.

(12) Coating systems comprising at least one layer made at least essentially of ZrO.sub.2 according to the present invention may be used for providing electrically insulating properties to parts of medical devices, or at least pans of medical components or instruments, which may be electrosurgical devices or which may be comprised in electrosurgical devices.

(13) Particularly, a coating system according to the present invention could be used for avoiding electrical shock of the persons which are in contact with the medical device during its use.

(14) The present invention also includes methods for coating substrates.