标签: thermistor

OK, it's time to make fun of a patent and I have one with an unassuming name: "Heated eyewear". Yup, you heard that right. In the abstract, the first reason given is to provide heat that may be sufficient to provide warmth to a wearer of the eyewear. Huh – so the double speak starts. Now just in case you are wondering, this is patent 7,410,254 issued in August 2008 – so actually quite recent. I would like to concentrate on description for figure 2 of the patent. It reads: In the embodiment shown, the power source 24 is electrically connected to a voltage protection element 26, such as a fuse. The voltage protection element 26 is in turn electrically connected to an output amplifier 28. The output amplifier 28 is in turn connected to a thermistor 30. The thermistor 30 may function to regulate the amount of heat generated by the heating element 16. The thermistor 30 is electrically connected to the heating element 16 in the frame 14 by a connecting wire 32. According to one embodiment, the connecting wire 32 is permanently connected to the heating element 16 in the frame, while in an alternative embodiment, the hinge 22 is configured to selectively connect the connecting wire 32 to the heating element 16. For instance, in one such embodiment, the connecting wire 32 may be connected to the heating element 16 when the ear-piece 20 is moved to the open position, e.g., the position at which the eyeglasses 10 are worn, while the connecting wire 32 may be disconnected from the heating element 16 when the ear-piece 20 is moved to the closed position, e.g., the position at which the eye glass are stored. So, how is this meant to work? We feed a power source into the input of an amplifier and somehow it magnifies the power. Then a thermistor is meant to control to temperature source but it is positioned so that it will only respond to ambient temperature. The switch (don't you love that description of a switch) is positioned such that power would continue to be consumed and would expose a live connection that is clearly so shocking that it needs a fuse. Oh, and in case you are wondering what 36 and 38 are- well that would be a GPS and a light detector and 40 is your built in memory and 25 is your backup power source just in case you run out of juice. Brian Bailey EE Times