Abstract: An optical imaging system includes a first lens having positive refractive power, a second lens, a third lens, and a fourth lens, arranged sequentially from an object side along an optical axis. The first lens through the fourth lens are spaced apart from each other along the optical axis in a paraxial region. A total focal length f of a lens unit including the first lens through the fourth lens and half (IMG HT) of a diagonal length of an imaging surface of an image sensor satisfy f/IMG HT>4.9. An effective aperture radius of an object-side surface of the first lens and an effective aperture radius of an object-side surface of the second lens are both greater than effective aperture radii of an object-side surface and an image-side surface of each of the lenses other than the first lens and the second lens.

Abstract: An optical imaging system includes: a plurality of lenses disposed along an optical axis; and a reflection member closer to an object than the plurality of lenses, and including a reflection surface configured to change a path of light; wherein the plurality of lenses are spaced apart from each other by preset distances along the optical axis; and the condition 0.9<DF/DC<1.3 is satisfied, where DF is an effective aperture radius of an image-side surface of a lens closest to an image sensor among the plurality of lenses, and DC is an effective aperture radius of an object-side surface of a lens closest to the reflection member among the plurality of lenses.

Abstract: A spacer includes: an opening through which light passes; an inner side surface forming the opening; and a protruding portion including a plurality of protrusions protruding from the inner side surface. Lengths of the plurality of protrusions vary in a circumferential direction of the protruding portion.

Abstract: The present invention relates to a catalyst used in a dehydrogenation reaction of a linear hydrocarbon gas in a range of C3 to C4, and provides a dehydrogenation catalyst which is deposited on a carrier obtained by changing the phase of platinum, an auxiliary metal and an alkali metal, wherein the platinum and the auxiliary metal are present as a single complex within a certain thickness from the outer edges of the catalyst in an alloy form.

Abstract: An optical imaging system includes a first lens having positive refractive power, a second lens, a third lens, a fourth lens, and a fifth lens, arranged in order from an object side. The first lens is shaped such that a length of a first axis, which intersects an optical axis, is greater than a length of a second axis, which intersects the optical axis and is perpendicular to the first axis. The optical imaging system satisfies 4.5<TTL/IMG HT<6.5; 0.87<TTL/f<1.31; and 0.65<L1S1es/L1S1el<0.9.

Abstract: An optical imaging system includes a first lens having positive refractive power, a second lens, a third lens, and a fourth lens, arranged sequentially from an object side along an optical axis. The first lens through the fourth lens are spaced apart from each other along the optical axis in a paraxial region. A total focal length f of a lens unit including the first lens through the fourth lens and half (IMG HT) of a diagonal length of an imaging surface of an image sensor satisfy f/IMG HT>4.9. An effective aperture radius of an object-side surface of the first lens and an effective aperture radius of an object-side surface of the second lens are both greater than effective aperture radii of an object-side surface and an image-side surface of each of the lenses other than the first lens and the second lens.

Abstract: An optical imaging system includes: a first lens having positive refractive power, a second lens having negative refractive power, a third lens having negative refractive power, a fourth lens having refractive power, a fifth lens having refractive power, and an image sensor on an image side of the fifth lens such that the fifth lens is most adjacent to the image sensor. The first to fifth lenses are sequentially disposed from an object side to an image side of the optical imaging system and the optical imaging system includes a total of five lenses. The optical imaging system satisfies 1.3<TTL/BFL<3.5, where TTL is a distance from an object-side surface of the first lens to an imaging plane of the image sensor, and BFL is a distance from an image-side surface of the fifth lens to the imaging plane of the image sensor.

Abstract: An optical imaging system includes: a first lens having a concave image-side surface; a second lens having refractive power; a third lens having a concave image-side surface; a fourth lens having a concave object-side surface or a convex image-side surface; a fifth lens having refractive power; a sixth lens having a concave image-side surface; and a seventh lens having negative refractive power. The first to seventh lenses are sequentially disposed from an object side and 1.62<(N2+N5+N6)/3, where N2 is a refractive index of the second lens, N5 is a refractive index of the fifth lens, and N6 is a refractive index of the sixth lens.

Abstract: An optical imaging system includes a first lens having positive refractive power, a second lens, a third lens, a fourth lens, and a fifth lens, arranged in order from an object side. The first lens is shaped such that a length of a first axis, which intersects an optical axis, is greater than a length of a second axis, which intersects the optical axis and is perpendicular to the first axis. The optical imaging system satisfies 4.5<TTL/IMG HT<6.5; 0.87<TTL/f<1.31; and 0.65<L1S1es/L1S1el<0.9.

Abstract: An optical imaging system includes a first lens, a second lens, a third lens, and a fourth lens sequentially disposed from an object side toward an image side on an optical axis, and a reflecting member disposed closer to the object side, as compared to the first lens, and having a reflecting surface configured to change a path of light to be incident to the first to fourth lenses. The first to fourth lenses are disposed to be spaced apart from each other by a preset distance along the optical axis, and 1.3<TTL/BFL<3.5, where TTL is a distance from an object-side surface of the first lens to an imaging plane of an image sensor, and BFL is a distance from an image-side surface of the fourth lens to the imaging plane of the image sensor.

Abstract: An optical imaging system includes: a first lens having a concave image-side surface; a second lens having refractive power; a third lens having a concave image-side surface; a fourth lens having a concave object-side surface or a convex image-side surface; a fifth lens having refractive power; a sixth lens having a concave image-side surface; and a seventh lens having negative refractive power. The first to seventh lenses are sequentially disposed from an object side and 1.62<(N2+N5+N6)/3, where N2 is a refractive index of the second lens, N5 is a refractive index of the fifth lens, and N6 is a refractive index of the sixth lens.

Abstract: An optical imaging system includes a first lens, a second lens, a third lens, and a fourth lens sequentially disposed from an object side toward an image side on an optical axis, and a reflecting member disposed closer to the object side, as compared to the first lens, and having a reflecting surface configured to change a path of light to be incident to the first to fourth lenses. The first to fourth lenses are disposed to be spaced apart from each other by a preset distance along the optical axis, and 1.3<TTL/BFL<3.5, where TTL is a distance from an object-side surface of the first lens to an imaging plane of an image sensor, and BFL is a distance from an image-side surface of the fourth lens to the imaging plane of the image sensor.

Abstract: An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, sequentially disposed from an object side, wherein the first to fifth lenses are spaced apart from each other by predetermined distances along an optical axis in a paraxial region, the first lens and the second lens each have a non-circular shape when viewed in an optical axis direction, and the optical imaging system satisfies 0.62398<ZS1/ZS2<1.36318, where ZS1 is a ratio of an area of an object-side surface of the first lens to a distance from the object-side surface of the first lens to an imaging plane of an image sensor, and ZS2 is a ratio of an area of an object-side surface of the second lens to a distance from the object-side surface of the second lens to the imaging plane of the image sensor.

Abstract: An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, sequentially disposed from an object side, wherein the first to fifth lenses are spaced apart from each other by predetermined distances along an optical axis in a paraxial region, the first lens and the second lens each have a non-circular shape when viewed in an optical axis direction, and the optical imaging system satisfies 0.62398<ZS1/ZS2<1.36318, where ZS1 is a ratio of an area of an object-side surface of the first lens to a distance from the object-side surface of the first lens to an imaging plane of an image sensor, and ZS2 is a ratio of an area of an object-side surface of the second lens to a distance from the object-side surface of the second lens to the imaging plane of the image sensor.

Abstract: An optical imaging system includes a first lens having positive refractive power, a second lens, a third lens, and a fourth lens, arranged sequentially from an object side along an optical axis. The first lens through the fourth lens are spaced apart from each other along the optical axis in a paraxial region. A total focal length f of a lens unit including the first lens through the fourth lens and half (IMG HT) of a diagonal length of an imaging surface of an image sensor satisfy f/IMG HT >4.9. An effective aperture radius of an object-side surface of the first lens and an effective aperture radius of an object-side surface of the second lens are both greater than effective aperture radii of an object-side surface and an image-side surface of each of the lenses other than the first lens and the second lens.

Abstract: An optical imaging system includes a first lens having positive refractive power, a second lens, a third lens, and a fourth lens, arranged sequentially from an object side along an optical axis. The first lens through the fourth lens are spaced apart from each other along the optical axis in a paraxial region. A total focal length f of a lens unit including the first lens through the fourth lens and half (IMG HT) of a diagonal length of an imaging surface of an image sensor satisfy f/IMG HT>4.9. An effective aperture radius of an object-side surface of the first lens and an effective aperture radius of an object-side surface of the second lens are both greater than effective aperture radii of an object-side surface and an image-side surface of each of the lenses other than the first lens and the second lens.

Abstract: An optical imaging system includes a first lens, a second lens, a third lens, and a fourth lens sequentially disposed from an object side toward an image side on an optical axis, and a reflecting member disposed closer to the object side, as compared to the first lens, and having a reflecting surface configured to change a path of light to be incident to the first to fourth lenses. The first to fourth lenses are disposed to be spaced apart from each other by a preset distance along the optical axis, and 1.3<TTL/BFL<3.5, where TTL is a distance from an object-side surface of the first lens to an imaging plane of an image sensor, and BFL is a distance from an image-side surface of the fourth lens to the imaging plane of the image sensor.

Abstract: An optical imaging system includes a first lens having positive refractive power, a second lens, a third lens, a fourth lens, and a fifth lens, arranged in order from an object side. The first lens is shaped such that a length of a first axis, which intersects an optical axis, is greater than a length of a second axis, which intersects the optical axis and is perpendicular to the first axis. The optical imaging system satisfies 4.5<TTL/IMG HT<6.5; 0.87<TTL/f<1.31; and 0.65<L1S1es/L1S1el<0.9.

Abstract: An optical imaging system includes a first lens having positive refractive power, a second lens, a third lens, a fourth lens, and a fifth lens, arranged in order from an object side. The first lens is shaped such that a length of a first axis, which intersects an optical axis, is greater than a length of a second axis, which intersects the optical axis and is perpendicular to the first axis. The optical imaging system satisfies 4.5<TTL/IMG HT<6.5; 0.87<TTL/f<1.31; and 0.65<L1S1es/L1S1el<0.9.

Abstract: An optical imaging system includes a first lens, a second lens, a third lens, and a fourth lens sequentially disposed from an object side toward an image side on an optical axis, and a reflecting member disposed closer to the object side, as compared to the first lens, and having a reflecting surface configured to change a path of light to be incident to the first to fourth lenses. The first to fourth lenses are disposed to be spaced apart from each other by a preset distance along the optical axis, and 1.3<TTL/BFL<3.5, where TTL is a distance from an object-side surface of the first lens to an imaging plane of an image sensor, and BFL is a distance from an image-side surface of the fourth lens to the imaging plane of the image sensor.