Applicator with thermal contact sensors
Disclosed is a thermal contact sensor for use in aesthetic skin by heat treatment for altering the aesthetic appearance of a subject. The thermal contact sensor measures the difference in sensor temperature when in contact or absence of contact with the skin and automatically operates a source of optical radiation to heat the skin.
1. A method of thermal contact detection, comprising:
applying to a skin of a subject an applicator containing a thermal contact sensor that comprises:
a metal frame;
a can-like housing having housing walls and a bottom which is thinner than the housing walls;
at least one temperature sensor and a heater; and
a flexible printed circuit board including enhanced solder coated pads configured to receive the at least one temperature sensor and the heater;
operating the thermal contact sensor in one of a first mode, a second mode and a third mode to determine whether the thermal contact sensor is in contact with the skin of the subject;
wherein operating the thermal contact sensor in the first mode comprises operating the heater to maintain a temperature difference between the skin and the metal frame;
wherein operating the thermal contact sensor in the second mode comprises measuring power supplied to the thermal contact sensor; and
wherein operating the thermal contact sensor in the third mode comprises measuring a difference in a thermal inertia of the thermal contact sensor in an idle state and in contact with the skin, comprising:
heating the can-like housing with the heater;
measuring the time it takes the heater to raise the temperature of the thermal contact sensor from 15° C. to 38° C.;
if the elapsed time it takes the heater to raise the temperature of the thermal contact sensor is less than 400 msec, determining that there is no contact of the thermal contact sensor with the skin; and
if the elapsed time it takes the heater to raise the temperature of the thermal contact sensor is more than 600 msec, determining that there is a contact of the thermal contact sensor with the skin.
2. The method of thermal contact detection of claim 1 , wherein operating the thermal contact sensor in the first mode further comprises:
attaching securely and firmly the metal frame, and the thermal contact sensor to the skin; and
if the sensed sensor temperature is 20° C. or more, determining a presence of contact of the thermal contact sensor with the skin; and
if the sensed temperature is 15° C. or less, determining an absence of contact of the thermal contact sensor with the skin.
3. The method of thermal contact detection of claim 1 , wherein operating the thermal contact sensor in the first mode further comprises: using an internal processor to operate the heater to maintain the temperature difference between the skin and the metal frame.
4. The method of thermal contact detection of claim 1 , wherein operating the thermal contact sensor in the first mode further comprises: using an internal processor to operate the heater in pulse mode, in a cycle where the heater is on for two seconds and is off for next two seconds.
5. The method of thermal contact detection of claim 4 , wherein operating the thermal contact sensor in the first mode further comprises: sensing and transmitting a measured temperature of the thermal contact sensor when the heater is off.
6. The method of thermal contact detection of claim 1 , wherein operating the thermal contact sensor in the second mode further comprises
operating the heater in closed-loop control mode to maintain the thermal contact sensor at a temperature of 38° C.; and
if there is an increase in electric power consumed by the heater, determining there is contact of the thermal contact sensor with the skin.
7. The method of thermal contact detection of claim 1 , wherein the metal frame comprises stainless steel.
8. The method of thermal contact detection of claim 1 , wherein operating the thermal contact sensor in one of the first mode, the second mode and the third mode consists of operating the thermal contact sensor in the first mode.
9. The method of thermal contact detection of claim 1 , wherein operating the thermal contact sensor in one of the first mode, the second mode and the third mode consists of operating the thermal contact sensor in the second mode.
10. The method of thermal contact detection of claim 1 , wherein operating the thermal contact sensor in one of the first mode, the second mode and the third mode consists of operating the thermal contact sensor in the third mode.