MEMS-based zoom lens system
AssigneeNational University of Singapore
InventorsGuangya Zhou, Hongbin Yu, Fook Siong Chau
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Abstract
The present application provides a micromechanical (MEMS) based zoom lens system, for use in miniature device applications, such as miniature electronic imaging devices. The MEMS-based zoom lens system comprises at least four optical elements, or two Alvarez or Lohmann lenses, that are configured for passage of optical signals therethrough along an optical signal path. Each optical element is MEMS-driven and displaceable in a direction substantially transverse to the optical signal path. In use, the transverse displacement of the optical elements vary an overall focal length of the MEMS zoom lens system such as to provide an optical zoom function. A method of manufacturing a MEMS zoom lens system is also provided in a further aspect.
Claims48
A zoom lens system comprising:
- a plurality of microactuators, each configured to displace at least one optical element;
- at least four optical elements, each of the at least four optical elements configured for passage of optical signals therethrough along an optical signal travel path, each of the at least four optical elements including at least one free-form surface,
- the at least four optical elements positioned in a pair-wise configuration such that a first and a second optical element comprise a first pair having a variable focal length and a third and a fourth optical element comprise a second pair having a variable focal length, each of the at least four optical elements displaceable by operation of the plurality of microactuators in a direction substantially transverse to the optical signal travel path to cause a change in optical power of the system.
A method for providing an optical zoom, comprising:
- providing at least four optical elements, each of the at least four optical elements configured for passage of optical signals therethrough along an optical signal travel path, each of the at least four optical elements including at least one free-form surface;
- and
- positioning the at least four optical elements in a pair-wise configuration such that a first and a second optical element form a first pair of optical elements having a variable focal length and a third and a fourth optical element form a second pair of optical elements having a variable focal length, wherein
- activating a plurality of microactuators displaces at least two of the at least four optical elements in a direction substantially transverse to the optical signal travel path to cause a change in optical power of the combination of the first and second pair of optical elements.
A method for manufacturing a zoom lens system comprising:
- fabricating at least two movable microstructure assemblies as integrated units, the movable microstructure assemblies comprising:
- a platform having a generally planar first surface, a generally planar second surface, and a thickness between the first surface and the second surface, the platform configured for carrying a lens element such that an optical axis of the lens element is substantially perpendicular to the first and second surfaces;
- a reference support structure;
- a flexure suspension coupled between the platform and the reference support structure, the flexure suspension configured for elastic deformation along a direction transverse to the optical axis of the lens element;
- and
- a displacement mechanism configured to apply a displacement force to the platform in a direction transverse to the optical axis of the lens element;
- providing, for each assembly, a first lens element having a freeform surface;
- and
- establishing an alignment of the freeform surfaces relative to the movable microstructure assembly.
An electronic imaging device comprising:
- an optical window having a cross sectional area transverse to an optical axis and configured to allow propagation of optical signals to the electronic device along the optical axis;
- a miniaturized zoom lens system configured to receive optical signals propagating through the optical window along the optical axis, the zoom lens system comprising at least four optical elements, each of the at least four optical elements including at least one free-form surface, the at least four optical elements positioned in a pair-wise configuration such that a first and a second optical element form a first pair having a variable focal length and a third and a fourth optical element form a second pair having a variable focal length, each of the at least four optical elements displaceable by at least one of a plurality of microactuators in a direction substantially transverse to the optical signal travel path to allow a change in optical power of one or both of the first and second pairs;
- and
- an image sensor configured to receive optical signals propagating through the zoom lens system along the optical axis.
Dependencies are inferred from the claim text.