I think you are right, or at least you where when the technology was new. The crystals Greywolf is talking about are piezoelectric, they bend slightly when a voltage is applied to them (if they are cut correctly relative to the crystal structure). By providing a ring of such crystals it is possible to use this bending to move the focussing mechanisms.
The "Ultrasonic" name indicates the frequency of the crystal movements. The crystals give many very small movements at a high frequency which adds up to the required movement. OK, it's been some time since I read the patent, but I think this is quite close to the actual technology. DagT > Fra: [EMAIL PROTECTED] > > I am not a mechanical engineer who could confirm > your claims but what I meant was where does the > "ultrasonic" or "hypersonic" came from were it not > for the piezo-electric effect ? (You apply a certain > electric potential to a crystal and that crystal > vibrates. Conversely you apply pressure to that > crystal and you get a electrical current back.) > .... > -- > Bo-Ming Tong > > ----- Original Message ----- > From: T Rittenhouse <[EMAIL PROTECTED]> > Date: Tuesday, August 26, 2003 9:32 pm > Subject: Re: My *ist film review > > > Ultrasonic motors are not neccessarily > piezo-electric. In fact I > > do not > > think piezo-electric motors are ultasonic motors > unless the term > > is being > > used for the crystal that converts DC into > ultrasonic AC. What I > > know as a > > piezo-electric motor is something that has a very > very limited > > movement as > > it is simply the deflection of a crystal element > converted to > > mechanicalmovement. In fact, I thought (never > actually researched > > it) that they were > > simply using a linear ultra-sonic (100kc or so) > motor to move a > > few elements > > in the lens for focusing. From what you are saying > Ultra (or > > Hyper) sonic is > > just advertising hype like Turbo has become. > > > > Ciao, > > Graywolf > > http://pages.prodigy.net/graywolfphoto > >
