Magnetically Actuated System

Abstract

A magnetically actuated system includes a conductor and a magnetic field apparatus to generate a magnetic field. The magnetic field apparatus includes magnets and magnetically permeable materials to focus the magnetic field in areas of the conductor that produce a drive torque when the conductor carries a current.

1 . An apparatus comprising:
 a first magnet oriented with a south pole facing down and a north pole facing up;   a second magnet oriented parallel to the first magnet, the second magnet having a north pole facing down and a south pole facing up;   a third magnet between, and oriented perpendicular to, the first and second magnets, the third magnet having a south pole facing the second magnet and a north pole facing the first magnet; and   a movable platform having a conductive coil nominally oriented in a platform plane above the first, second, and third magnets.   
   
   
       2 . The apparatus of  claim 1  wherein the movable platform includes a gimballed structure allowing the movable platform to rotate out of the platform plane on a first axis, the movable platform further including a reflective part that can rotate relative to the gimballed structure on a second axis substantially 90 degrees from the first axis. 
   
   
       3 . The apparatus of  claim 2  wherein the third magnet orientation is misaligned with respect to the first and second axes of the movable platform. 
   
   
       4 . The apparatus of  claim 1  further comprising:
 a fourth magnet above the first magnet and the platform plane, the fourth magnet having a south pole facing up and a north pole facing down; and   a fifth magnet above the second magnet and the platform plane, the fifth magnet having a south pole facing down and a north pole facing up.   
   
   
       5 . The apparatus of  claim 4  further comprising:
 at least one focusing plate of magnetically permeable material positioned between the platform plane and the fourth and fifth magnets to focus a resulting magnetic field in the platform plane.   
   
   
       6 . An apparatus comprising:
 a first magnet oriented with a south pole facing down and a north pole facing up;   a second magnet oriented parallel to the first magnet, the second magnet having a north pole facing down and a south pole facing up;   a movable platform having a conductive coil nominally oriented in a platform plane above the first and second magnets; and   a magnetically permeable core beneath the movable platform and between the first and second magnets.   
   
   
       7 . The apparatus of  claim 6  wherein the movable platform includes a gimballed structure allowing a portion of the movable platform to rotate out of the platform plane on two separate axes substantially 90 degrees apart. 
   
   
       8 . The apparatus of  claim 7  wherein the conductive coil has an inner outline and the magnetically permeable core is oriented beneath, and within the inner outline of, the conductive coil. 
   
   
       9 . The apparatus of  claim 8  wherein the inner outline of the conductive coil is elliptical. 
   
   
       10 . The apparatus of  claim 6  further comprising:
 a third magnet above the first magnet and the platform plane, the third magnet having a south pole facing up and a north pole facing down; and   a fourth magnet above the second magnet and the platform plane, the fourth magnet having a south pole facing down and a north pole facing up.   
   
   
       11 . The apparatus of  claim 10  further comprising:
 at least one focusing plate of magnetically permeable material positioned between the platform plane and the third and fourth magnets to focus a resulting magnetic field in the platform plane.   
   
   
       12 . The apparatus of  claim 11  wherein the conductive coil has an outer outline and the focusing plates are shaped to be outside the outer outline of the conductive coil. 
   
   
       13 . An apparatus comprising:
 a first magnet oriented with a south pole facing down and a north pole facing up;   a second magnet oriented parallel to the first magnet, the second magnet having a north pole facing down and a south pole facing up;   a movable platform having a conductive coil nominally oriented in a platform plane above the first and second magnets;   a third magnet above the first magnet and the platform plane, the third magnet having a south pole facing up and a north pole facing down;   a fourth magnet above the second magnet and the platform plane, the fourth magnet having a south pole facing down and a north pole facing up; and   at least one focusing plate of magnetically permeable material positioned between the platform plane and the third and fourth magnets to focus a resulting magnetic field in the platform plane.   
   
   
       14 . The apparatus of  claim 13  wherein the movable platform includes a reflective surface facing up, and the third and fourth magnets are shaped to allow light to impinge on the reflective surface. 
   
   
       15 . The apparatus of  claim 13  wherein the conductive coil has an outer outline and the focusing plates are shaped to be outside the outer outline of the conductive coil. 
   
   
       16 . The apparatus of  claim 15  further comprising a magnetically permeable core positioned between the first and second magnets and beneath the movable platform. 
   
   
       17 . A projection apparatus comprising:
 a light source to produce light;   a mirror to reflect the light, the mirror mounted on a movable platform, the movable platform including a conductive coil;   at least one magnet to produce a magnetic field; and   at least one piece of magnetically permeable material positioned to modify the magnetic field in the conductive coil.   
   
   
       18 . The projection apparatus of  claim 17  wherein the at least one piece of magnetically permeable material includes two focusing plates in a plane parallel to a plane of the conductive coil when the movable platform is at rest. 
   
   
       19 . The projection apparatus of  claim 18  wherein the two focusing plates are positioned on a first side of the movable platform in common with the mirror, and wherein the at least one magnet includes two magnets on an opposite side of the movable platform. 
   
   
       20 . The projection apparatus of  claim 19  wherein the at least one piece of magnetically permeable material further comprises a core of material positioned between the two magnets on the opposite side of the movable platform.