Apparatus for fractional skin treatment

Abstract

An apparatus for cosmetic RF skin treatment where the RF energy supply is isolated from the patient treated, such that in course of treatment no undesired current flows through the subject body. The apparatus includes an applicator for fractional skin treatment that has a tip with voltage to skin delivering elements, an isolating transformer located in close proximity to the tip and one or more capacitors serially connected with the tip and output coil of the isolating transformer.

1 . An applicator for fractional skin treatment, said applicator comprising:
 a tip including a plurality of voltage to skin delivering elements connected to a first RF port, and at least one large voltage to skin delivering element connected to a second RF port;   an isolating transformer located in close proximity to the tip with voltage to skin delivering elements; and   one or more capacitors serially connected with the tip and output coil of the isolating transformer.   
     
     
         2 . The applicator according to  claim 1  wherein the isolating transformer is operatively configured to reduce ground currents through parasitic capacitance. 
     
     
         3 . The applicator according to  claim 1  wherein the isolating transformer capacity is not more than 10 pF. 
     
     
         4 . The applicator according to  claim 1  wherein the capacitors serially connected with the tip and output coil are operatively configured to filter produced by plasma formed at the voltage to skin delivering elements low frequency currents. 
     
     
         5 . The applicator according to  claim 1  further comprising a current limiter operatively configured to set a maximum to the current which flows into the skin. 
     
     
         6 . The applicator according to  claim 5  wherein the current limiter further comprises an RF energy absorbing element. 
     
     
         7 . The applicator according to  claim 6  wherein the current limiter limits the current increase and directs a larger part of the current through the RF energy absorbing element. 
     
     
         8 . The applicator according to  claim 5  wherein the current limiter operates a fast switch closing a circuit directing the current to a energy absorbing element. 
     
     
         10 . The applicator according to  claim 5  wherein the tip is one of a group of tips consisting of disposable tips and of reusable tips. 
     
     
         10 . A disposable tip for an applicator for fractional skin treatment, said tip comprising:
 a substrate with one or more voltage to skin conducting elements located on the substrate and arranged into two clusters:
 a cluster of miniature discrete, voltage to skin application elements protruding from the substrate surface and terminated by dome type shapes; and 
 a cluster of voltage to skin application elements protruding from the substrate surface with an area substantially larger than the area of the terminated by dome type shapes electrodes; and 
   RF voltage connection elements.   
     
     
         11 . The disposable tip according to  claim 10  wherein the terminated by dome type shapes voltage to skin application elements are connected to one RF port. 
     
     
         12 . The disposable tip according to  claim 10  wherein the voltage to skin application elements with area substantially larger than the area of the terminated by dome type shapes are connected to another RF port. 
     
     
         13 . The disposable tip according to  claim 10  further comprising a mechanism enabling quick removal and attachment of the substrate to the applicator. 
     
     
         14 . An apparatus comprising:
 an applicator including a tip with a plurality of voltage to skin delivering elements connected to a first RF port and at least one large voltage to skin delivering element connected to a second RF port;
 an isolating transformer located in close proximity to the tip with voltage to skin delivering elements; and 
   one or more capacitors serially connected with the tip and output coil of the isolating transformer; and   a controller including at least a processor and a memory, and governing operation of the apparatus and to control a treatment process; and   wherein said memory stores a look-up-table (LUT) containing proper treatment parameters derived in process of apparatus calibration.   
     
     
         15 . The apparatus according to  claim 14  wherein the process of apparatus calibration includes use of a variable resistance connected instead of a subject to an RF voltage supply and modeling different skin impedance and the tip behavior. 
     
     
         16 . The apparatus according to  claim 14  wherein the controller during an RF pulse controls energy delivered to skin by monitoring skin impedance in a continuous or pseudo continuous mode. 
     
     
         17 . The apparatus according to  claim 16  wherein the controller increases time of the RF pulse, when the skin resistance falls below a pre-set threshold. 
     
     
         18 . The apparatus according to  claim 16  wherein the controller cuts off RF energy supply and excludes inefficient RF pulses if the skin impedance is below a predetermined skin impedance value. 
     
     
         19 . The apparatus according to  claim 16  wherein the controller to prevent pain cuts off RF energy supply if the skin impedance is above a predetermined skin impedance value. 
     
     
         20 . The apparatus according to  claim 16  wherein the controller maintains the amount of energy delivered to skin fixed if the skin resistance increase is detected.