Abstract: The present embodiment relates to a dual lens drive device that comprises: a housing; a first bobbin which is disposed to move in a first direction inside the housing; a second bobbin which is disposed to move in the first direction inside housing and is spaced apart from the first bobbin; a first coil which is disposed on the first bobbin; a second coil which is disposed on the second bobbin; a magnet which is disposed in the housing and faces the first coil and the second coil; a base which is disposed below the housing; a substrate which comprises a circuit member having a third coil disposed to face the magnet between the housing and the base; and a support member which movably supports the housing with respect to the substrate, wherein the housing is integrally formed.

Abstract: Disclosed is a piezoelectric material including stereocomplex crystals of poly(D-lactic acid) (PDLA) and poly(L-lactic acid) (PLLA), wherein poly(D-lactic acid) and poly(L-lactic acid) are crystallized into a stereocomplex, thus exhibiting superior heat resistance and piezoelectric properties. This piezoelectric material, which is obtained using poly(lactic acid), can be produced at very low cost compared to when using PVDF, and is configured to include stereocomplex crystals of PDLA and PLLA and can thus manifest high thermal stability and piezoelectric properties, compared to when using conventional PLLA alone. Such a piezoelectric material can be efficiently utilized in a variety of fields in which low production cost, high processing temperature in the manufacturing process, or high-temperature stability of piezoelectric material products is required.

Abstract: A method of producing a piezoelectric nanofiber web, includes: dissolving polylactic acid in a solvent, thus preparing a spinning solution; and electrospinning the spinning solution, yielding a nanofiber web, wherein at least 80% of a monomer for the polylactic acid comprises an L-isomer or a D-isomer, and wherein the solvent is a mixture comprising chloroform and one of N,N-dimethylacetamide(DMAc), N,N-dimethylformamide(DMF) and dimethylsulfoxide(DMSO).

Abstract: Disclosed is a piezoelectric material including stereocomplex crystals of poly(D-lactic acid) (PDLA) and poly(L-lactic acid) (PLLA), wherein poly(D-lactic acid) and poly(L-lactic acid) are crystallized into a stereocomplex, thus exhibiting superior heat resistance and piezoelectric properties. This piezoelectric material, which is obtained using poly(lactic acid), can be produced at very low cost compared to when using PVDF, and is configured to include stereocomplex crystals of PDLA and PLLA and can thus manifest high thermal stability and piezoelectric properties, compared to when using conventional PLLA alone. Such a piezoelectric material can be efficiently utilized in a variety of fields in which low production cost, high processing temperature in the manufacturing process, or high-temperature stability of piezoelectric material products is required.

Abstract: Disclosed are a nanofiber web piezoelectric material and a method of producing the same, wherein a spinning solution of polylactic acid (PLA) in a solvent is electrospun, yielding a nanofiber web, thereby exhibiting piezoelectric properties without additional drawing. This piezoelectric material is remarkably cost-effective, can exhibit superior piezoelectric properties, can be used to manufacture inexpensive piezoelectric products, and obviates any additional drawing because the PLA chain is drawn during electrospinning. The drawing force induced by a high electric field between the needle and the collector enables the formation of 31 helical ?-crystal chains in a uniaxial direction even without any other drawing process. This PLA nanofiber web is very thin and flexible, the PLA chains are effectively aligned in an electric field direction due to the high DC voltage used for electrospinning, and helical ? conformation is easily formed in a single process using electrospinning.

Abstract: The present invention relates to a sensor comprising a material which generates an electrical signal in response to elongation. More particularly, the present invention is directed to an apparatus for measuring a length or volume change, which comprises a sensor comprising a piezoelectric material which generates an electrical signal in response to elongation.