Abstract: A lens assembly includes a lens barrel, a plurality of lenses arranged inside the lens barrel along an optical axis, and a cover member fixed to an end of the lens barrel on a subject side and fixing a last lens of the plurality of lenses on the subject side, wherein outer diameters of the plurality of lenses decrease from the subject side to an image side, and an outer diameter of the lens barrel is constant or smaller from the subject side to the image side.

Abstract: An optical imaging system includes a first lens having a convex image-side surface, a second lens having a concave object-side surface, a third lens, a fourth lens, and a fifth lens disposed sequentially from an object side. The optical imaging system satisfies 4.8<f/IMG_HT<9.0, where f is a focal length of the optical imaging system, and IMG_HT is half a diagonal length of an imaging surface of an image sensor.

Abstract: A trimaran type WIG (Wing-In-Ground) effect ship with a minimum waterplane area is disclosed. This WIG ship comprises a main hull and two half-submerged sub-hulls each having a minimum waterplane area capable of minimizing the wave resistance and appendage resistance of the ship, thus reducing speed loss on rough water. The WIG ship also has main and sub-wings and an effective propelling mechanism, designed such that they produce a strong lift force allowing a take-off of the ship sailing on water even at a low speed. The WIG ship is thus excellent in its seakeeping and maneuverability on the rough water. In the WIG ship, the main hull is intermediately positioned between the main wings and comprises a slender and half-submerged body, and bears 60% of the total displacement of the ship. The sub-hulls are respectively provided under the outer ends of the main wings, and each bear 20% of the total displacement, and act as an end plate.

Abstract: A trimaran type WIG (Wing-In-Ground) effect ship with a minimum waterplane area is disclosed. This WIG ship comprises a main hull and two half-submerged sub-hulls each having a minimum waterplane area capable of minimizing the wave resistance and appendage resistance of the ship, thus reducing speed loss on rough water. The WIG ship also has main and sub-wings and an effective propelling mechanism, designed such that they produce a strong lift force allowing a take-off of the ship sailing on water even at a low speed. The WIG ship is thus excellent in its seakeeping and maneuverability on the rough water. In the WIG ship, the main hull is intermediately positioned between the main wings and comprises a slender and half-submerged body, and bears 60% of the total displacement of the ship. The sub-hulls are respectively provided under the outer ends of the main wings, and each bear 20% of the total displacement, and act as an end plate.