New Invention: Electrodynamic Micro-Manipulator

22 May 2019

The handling of non-spherical micron-sized objects is a challenge for the manufacturing industry and for the wider exploitation of nanomaterials. Current manipulation techniques consist of pick-and-place machines used to place microelectronic components onto circuit boards, and optical methods that use laser radiation to manipulate objects. Pick-and-place methods are unsuitable for objects smaller than 100 microns because electrostatic and Van der Waals attraction prevents their release. This is particularly true of planar objects, such as 2D nanomaterials, which posses a large surface area. Optical methods work well for nanometre-sized objects but scale poorly to larger object sizes because of the increasing optical power required, which causes heating.

Oxford researchers have developed a novel and robust approach for the manipulation of non-spherical bodies, in which an electrical field levitates, aligns and orients the object, under air or vacuum conditions. A number of opportunities could open in the area of manufacturing processes of microcomponents and wide area nanomaterial integration as a result of this technology.

The manipulation of micro-sized objects

The handling of micron-sized objects is particularly challenging because electrostatic forces dominate inertial forces. This is particularly relevant for non-spherical objects, such as thin sheets or wires, as their large surface area makes mechanically releasing them difficult.

Pick-and-place machines are currently used to handle small objects, for example to precisely place a broad range of electronic components onto circuit boards that are used afterwards in computers, consumer electronics, medical and industrial equipment among others. Despite the popularity of the technique for objects above 100 microns in size, it is poorly suited for fragile micron-sized particles.

Alternative methods for manipulating microscopic objects and/or for performing micro-fabrication include optical tweezers, which employs a focused laser beam to physically hold and move the objects in an aqueous environment; and laser radiation for the optical levitation of spherical objects in the air or under vacuum.

Other methods are known, however, they are restricted to certain materials, classes of application and/or require complex apparatus. The lack of methods to reliably manipulate objects in the 10-100 micron size range is further complicated by the high fragility and deformability of non-spherical objects.

Electrodynamic Micro-Manipulation

Researchers at Oxford have tackled this limitation and developed a novel and robust approach for the manipulation of non-spherical bodies. The method applies an electrical field to levitate, align and orient anisotropic objects and can be used to completely constrain the rotational degrees-of-freedom of the objects.

Advantages of the technology include:

  • Applicable to non- spherical shapes, including nanowires, nanorods, fibres and graphene-like 2D crystals
  • Non-contact handling – the object’s purity is conserved during its manipulation
  • Stable alignment and orientation for a controlled inspection of the object
  • The full 3D orientation of the object

The method opens a plethora of new opportunities in manufacturing processes, such as the formation of complex heterogeneous assemblies which could be a game changer in the production of microcomponents for the next generation of electronic devices.

Commercialisation

Oxford University Innovation Ltd. has filed a priority patent application on the technology and welcome discussion with companies interested in licensing it for commercial development.