An apparatus for electromagnetic characterisation of internal features of an object, including a lens for placement between a source of electromagnetic energy and the object, the lens being composed of a first material having a first permittivity with openings therein containing or configured to receive one or more second materials having respective second permittivities different to the first permittivity, the openings being configured such that, when the openings contain the one or more second materials, the lens has a graded refractive index wherein an electromagnetic wave generated by the source and incident upon a first surface of the lens as a spherical wave exits a second surface of the lens in contact with a receiving surface of the object substantially as a plane wave, and a refractive index of the lens at the second surface of the lens substantially matches a refractive index of the object at the receiving surface to increase penetration of the plane wave into the object.

A thin-film optical device disclosed herein includes a metalens able to modulate the phase of incident light. The metalens includes a thin-film layer having a first index of refraction, an embedded layer within the thin-film layer, and the embedded layer having a second index of refraction greater than or equal to 1.5 and less than or equal to 3.0 times the first index of refraction. The embedded layer may fill a plurality of holes formed on the thin film layer, with the depth, width, and spacing of holes all contribute to modulating the phase of light traveling through the metalens.

According to one aspect of the technique of the present disclosure, there is provided a mobile communication terminal. The mobile communication terminal includes a main body, a display disposed at a front surface of the main body, a first camera group disposed at the front surface and including one or more cameras, a second camera group disposed at a rear surface of the main body that is opposite to the front surface and including one or more cameras, a third camera disposed at a first installation surface of the main body, which is different from the front surface and the rear surface, and an operation processor configured to: (a) display on the display an image selected from among a first image received through the first camera group, a second image received through the second camera group, and a third image received through the third camera.

An embodiment of a camera module includes a holder configured such that the upper and lower portions of the holder are open and such that a first hole and a second hole, opposite to the first hole, are formed in the side surface of the holder, a first lens unit coupled to the upper portion of the holder, a second lens unit coupled to the lower portion of the holder, and a liquid lens disposed in the first hole and the second hole of the holder between the first lens unit and the second lens unit, the liquid lens protruding outward from the side surface of the holder, wherein at least a portion of the liquid lens may be spaced apart from the inner surface of the holder.

An embodiment of a camera module includes a holder configured such that the upper and lower portions of the holder are open and such that a first hole and a second hole, opposite to the first hole, are formed in the side surface of the holder, a first lens unit coupled to the upper portion of the holder, a second lens unit coupled to the lower portion of the holder, and a liquid lens disposed in the first hole and the second hole of the holder between the first lens unit and the second lens unit, the liquid lens protruding outward from the side surface of the holder, wherein at least a portion of the liquid lens may be spaced apart from the inner surface of the holder.

An image display apparatus including a first waveguide, a second waveguide, a focus tunable lens positioned between the first waveguide and the second waveguide, and a display engine configured to control a focal length of the focus tunable lens and control the display engine to output first light forming the first virtual image and second light forming the second virtual image, wherein at least a portion of the first light is diffracted from the first waveguide and at least a portion of the second light diffracted from the second waveguide is incident on the first waveguide through the focus tunable lens.

The present invention relates to an anti-fog device including: a lens unit including a first lens positioned outside and a second lens spaced apart from the first lens while facing the first lens to form an internal space and having a liquid filled in the internal space; a temperature control unit controlling a temperature of the liquid; and a circulation unit of which one side is connected to the internal space and the other side is connected to the temperature control unit to form a passage through which the liquid circulates. According to the present invention, it is possible to prevent record deterioration of a sports event or an accident during exercise by preventing occurrence of fog of goggles or swimming goggles to secure a visual field.

The present invention relates to an anti-fog device including: a lens unit including a first lens positioned outside and a second lens spaced apart from the first lens while facing the first lens to form an internal space and having a liquid filled in the internal space; a temperature control unit controlling a temperature of the liquid; and a circulation unit of which one side is connected to the internal space and the other side is connected to the temperature control unit to form a passage through which the liquid circulates. According to the present invention, it is possible to prevent record deterioration of a sports event or an accident during exercise by preventing occurrence of fog of goggles or swimming goggles to secure a visual field.

An embodiment of the present invention relates to an imaging lens comprising: a first lens having positive (+) refractive power; a second lens having negative (−) refractive power; a third lens having negative (−) refractive power; a fourth lens; a fifth lens having negative (−) refractive power; and a sixth lens, wherein the first to sixth lenses are successively arranged from an object side to an image side, the first to third, fifth, and sixth lenses are solid lenses, and the fourth lens comprises a focus-tunable lens.

An embodiment of the present invention relates to an imaging lens comprising: a first lens having positive (+) refractive power; a second lens having negative (−) refractive power; a third lens having negative (−) refractive power; a fourth lens; a fifth lens having negative (−) refractive power; and a sixth lens, wherein the first to sixth lenses are successively arranged from an object side to an image side, the first to third, fifth, and sixth lenses are solid lenses, and the fourth lens comprises a focus-tunable lens.