Hair dryer having a ceramic heater

Abstract

A hair dryer according to one example embodiment includes an air flow conduit having an entrance and an exit. The hair dryer includes an air mover configured to induce air flow through the air flow conduit to the exit of the air flow conduit. The hair dryer includes a heater comprising a ceramic substrate and an electrically resistive trace on the ceramic substrate. The heater is positioned to supply heat generated by applying an electric current to the electrically resistive trace to air in the air flow conduit.

1 . A hair dryer, comprising:
 an air flow conduit having an entrance and an exit;   an air mover configured to induce air flow through the air flow conduit to the exit of the air flow conduit; and   a heater comprising a ceramic substrate and an electrically resistive trace on the ceramic substrate, the heater being positioned to supply heat generated by applying an electric current to the electrically resistive trace to air in the air flow conduit.   
     
     
         2 . The hair dryer of  claim 1 , further comprising:
 a thermal sensor; and   control circuitry of the heater,   wherein the thermal sensor is in electrical communication with the control circuitry of the heater for providing feedback regarding a temperature of the heater to the control circuitry of the heater.   
     
     
         3 . The hair dryer of  claim 2 , wherein the thermal sensor comprises at least one of a flag negative temperature coefficient thermistor or a beam negative temperature coefficient thermistor. 
     
     
         4 . The hair dryer of  claim 2 , wherein the control circuitry of the heater is configured to control the electric current applied to the electrically resistive trace, based on electrical communication from the thermal sensor, to ensure a surface temperature of the heater does not exceed 300 degrees Celsius. 
     
     
         5 . The hair dryer of  claim 1 , further comprising a heater housing within the air flow conduit, the heater being mounted on the heater housing. 
     
     
         6 . The hair dryer of  claim 5 , wherein the heater housing is composed of a plastic material having a maximum service temperature of at least 200 degrees Celsius. 
     
     
         7 . The hair dryer of  claim 5 , wherein an entry end of the heater housing is positioned within 50 mm of an output of the air mover. 
     
     
         8 . The hair dryer of  claim 1 , wherein the heater has a length, being a longest dimension of the heater, and the heater is positioned with its length aligned with a direction from the entrance to the exit of the air flow conduit. 
     
     
         9 . The hair dryer of  claim 1 , wherein the substrate is an aluminum oxide substrate, and the electrically resistive trace is directly on an exterior surface of the substrate. 
     
     
         10 . The hair dryer of  claim 1 , wherein the substrate has an electrical resistivity of at least 10 14  Ωcm. 
     
     
         11 . The hair dryer of  claim 1 , wherein the substrate is a laminated ceramic substrate and/or has fiber laser scribed edges. 
     
     
         12 . The hair dryer of  claim 1 , wherein the substrate has a thickness of no more than 1.5 mm. 
     
     
         13 . The hair dryer of  claim 1 , further comprising one or more further heaters,
 wherein each of the further heater(s) comprise a respective further ceramic substrate and a respective further electrically resistive trace on the further ceramic substrate, and each of the further heater(s) are positioned to supply heat generated by applying an electric current to their respective electrically resistive trace to air in the air flow conduit, and   wherein the heater and the further heater(s) are electrically connected to one another.   
     
     
         14 . The hair dryer of  claim 13 , wherein the heater and the further heater(s) are positioned with a length of each heater, being a longest dimension of the heater, aligned with a direction from the entrance to the exit of the air flow conduit and the heater and the further heater(s) are arranged in a polygon shape around a longitudinal axis of the air flow conduit. 
     
     
         15 . The hair dryer of  claim 13 , wherein a total power consumption of the hair dryer is no greater than 1500 W. 
     
     
         16 . The hair dryer of  claim 1 , wherein the heater includes one or more glass layers on an exterior face of the ceramic substrate that cover the electrically resistive trace for electrically insulating the electrically resistive trace. 
     
     
         17 . The hair dryer of  claim 1 , wherein the electrically resistive trace comprises silver and palladium. 
     
     
         18 . A hair dryer, comprising:
 an air flow conduit having an entrance and an exit;   an air mover configured to induce air flow through the air flow conduit to the exit of the air flow conduit; and   a heater comprising a ceramic substrate and an electrical resistor material on an exterior surface of the ceramic substrate, the heater being positioned to supply heat generated by applying an electric current to the electrical resistor material to air in the air flow conduit.   
     
     
         19 . The hair dryer of  claim 18 , further comprising:
 a thermal sensor; and   control circuitry of the heater,   wherein the thermal sensor is in electrical communication with the control circuitry of the heater for providing feedback regarding a temperature of the heater to the control circuitry of the heater.   
     
     
         20 . The hair dryer of  claim 18 , wherein the electrical resistor material comprises silver and palladium.