Impedance sensing epilator

• US 4,372,315 A
• Filed: 07/03/1980
• Issued: 02/08/1983
• Est. Priority Date: 07/03/1980
• Status: Expired due to Term

• Current Assignee: Hair Free Centers Incorporated
• Original Assignee: Hair Free Centers
• Inventors: Shapiro, Julius, Eliason, Andrew
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US06/165,669
• Time in Patent Office: 950 Days
• Field of Search: 128/303.13, 128/303.14, 128/303.17, 128/303.18, 128/421-423
• US Class Current: 606/36
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• CPC Class Codes: A61B 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 2017/00132 Setting operation time of a device A61B2017/00123 takes precedence
• CPC Class Codes: A61B 2017/00159 Pulse shapes
• CPC Class Codes: A61B 2017/0019 Means for setting or varying the pulse width
• CPC Class Codes: A61B 2017/00973 pedal-operated
• CPC Class Codes: A61B 2018/00452 Skin
• CPC Class Codes: A61B 2018/00476 Hair follicles
• CPC Class Codes: A61B 2018/00666 using a threshold value

Abstract

An epilator for treating a hair follicle of a subject utilizes a probe into which an RF pulse is applied. Shortly after the pulse is initiated, a measure of the impedance seen by the probe is determined and utilized for the purpose of adjusting the duration of the pulse such that the energy absorbed by the subject is independent of the impedance seen by the probe. As a consequence, the energy absorbed by the subject will have a predetermined maximum value substantially independent of the impedance seen by the probe.

Claims

1. In an epilator of the type which includes RF generator means, timing circuit means linked to said generator means for gating the output of said generator means into a series of RF energy pulses and probe means which receives the RF energy pulses, said probe means having a tip including a needle adapted to be inserted into a hair follicle of a subject undergoing epilation, the improvement comprising:

(a) sensing means, operative during the initial portion of a given pulse of RF energy, including a forward and reflected power bridge, for sensing the impedance actually perceived by the probe means tip, said bridge generating a control signal which is proportional to said sensed impedance; and

,

(b) control means, operative during the balance of said pulse, for automatically adjusting at least one pulse parameter, independently selected from the group consisting of duration and amplitude, responsive to said control signal;

whereby the amount of energy absorbed by the subject via the needle has a value per pulse which is adjusted around a preset value as a function of sensed impedance.

2. The improvement of claim 1 wherein the parameter varied by said control means is duration.

3. The improvement of claim 1 wherein the parameter varied by said control means is amplitude.

4. Apparatus comprising:

(a) RF generator means;

(b) timing circuit means linked to said generator means for gating the output of said RF generator means into a pulse;

(c) probe means which receives the RF pulse from said timing circuit means, said probe means having a tip including a needle adapted to be inserted into a hair follicle of a subject undergoing epilation;

(d) sensing means, operative during the initial portion of a given pulse of RF energy, including a forward and reflected power bridge, for sensing the impedance actually perceived by the probe means tip, said bridge generating a control signal which is proportional to said sensed impedance, and,

(e) control means, to which said signal is fed, for control of RF pulse characteristics.

5. The apparatus of claim 4 wherein said control means includes display means, activated by the signal from said sensing means, which presents a quantitative read-out of perceived impedance.

6. The apparatus of claim 4 wherein said control means includes:

(e) pulse parameter control means, operative during the balance of the pulse, for automatically adjusting either or both of pulse duration and pulse amplitude as a function of the signal from said sensing means;

whereby the amount of energy absorbed by the subject via the needle has a value per pulse which is adjusted around a preset value as a function of sensed impedance.

7. The apparatus of claim 6 which further includes threshold detector means, linked to said pulse parameter control means and responsive to the impedance sensed by said sensing means during an initial portion of a pulse, for detecting a condition where the impedance is greater than a predetermined value.

8. The apparatus of claim 7 which further includes means responsive to said detector means for terminating the pulse as soon as said condition is detected.

9. The apparatus of claim 6 wherein said pulse parameter control means includes a balanced attentuator functionally interposed between said timing circuit means and said forward and reflected power bridge.