Monday, June 19, 2006

US Patent 7061660 - MEMS Feedback Control

http://www.freepatentsonline.com/7061660.html

Most people familiar with the patent system realize that the US patent office typically issues several bad patents every week. This may be understandable given that several thousand patents are issued in any give week and, based upon even a conservative error rate estimate of a few percent, dozens of bad patents can result. Many of these bad patents result from prior art that is well known but not readily searchable in patent or technical databases or prior art that is hidden within a singular embodiment of a single reference. However, a few of these bad patents issue when there is a large quantity of available prior art but the Examiner somehow misses all of the art. This patent represents an extreme case of the latter. Claims 1 and 8 are exemplary:

1. A MEMS device, comprising: at least one movable member; semiconductor device having at least one property affected by the location of the movable member with respect to the semiconductor device; and a control circuit to limit movement of the movable member based on observation of the property affected by the semiconductor device.

Claim 1 basically covers many micromechanical accelerometers formed from silicon using feedback regulation for which hundreds of patents and pieces of technical literature have been published. One applicable example is http://www.freepatentsonline.com/5583290.pdf

8. A MEMS device of comprising: at least one movable member; a tunneling device having at least one property affected by the location of the movable member with respect to the tunneling device; and a control circuit to limit movement of the movable member based on observation of the property affected by the tunneling device.

Claim 8 basically covers most scanning tunneling microscopes for which hundreds of patents and pieces of scientific literature have been published over the last twenty years. One applicable example is http://www.freepatentsonline.com/4952857.pdf

One may ask how could a Patent Examiner allow a patent application with so much prior art against the claims? The answer lies not just in this individual Examiner's negligence but in the failure of the US patent office to form a centralized resource for searching MEMS related patents (or perhaps create a MEMS art unit?). Since this particular patent had some dependent claims drawn toward optical devices, the application went to an Examiner in the optical arts, who may know a lot about optics, but very little about the broader application of MEMS.

Lacking a centralized resource to search MEMS patents it is likely that many more of these bad patents will issue in the MEMS arena.