A lens assembly for portable devices comprises: an aperture stop, a plastic first lens element with positive refractive power having a convex object-side surface; a plastic second lens element with negative refractive power having a concave image-side surface and an object-side surface being concave in a peripheral region; a plastic third lens element with negative refractive power having a concave object-side surface and a convex image-side surface; a plastic fourth lens element with positive refractive power having an image-side surface being concave in a paraxial region and convex in a peripheral region; and an IR-cut filter (infrared-cut filter); wherein the RI.sub.min represents the minimum RI (relative illumination) of effective field and it satisfies the following relation: 0.36<RI.sub.min<0.65.

A lens assembly for portable devices comprises: an aperture stop, a plastic first lens element with positive refractive power having a convex object-side surface; a plastic second lens element with negative refractive power having a concave image-side surface and an object-side surface being concave in a peripheral region; a plastic third lens element with negative refractive power having a concave object-side surface and a convex image-side surface; a plastic fourth lens element with positive refractive power having an image-side surface being concave in a paraxial region and convex in a peripheral region; and an IR-cut filter(infrared-cut filter);wherein the RI.sub.min represents the minimum RI(relative illumination) of effective field and it satisfies the following relation: 0.36<RI.sub.min<0.65.

A lens assembly for portable devices comprises: an aperture stop, a plastic first lens element with positive refractive power having a convex object-side surface; a plastic second lens element with negative refractive power having a concave image-side surface and an object-side surface being concave in a peripheral region; a plastic third lens element with negative refractive power having a concave object-side surface and a convex image-side surface; a plastic fourth lens element with positive refractive power having an image-side surface being concave in a paraxial region and convex in a peripheral region; and an IR-cut filter(infrared-cut filter);wherein the RI.sub.min represents the minimum RI(relative illumination) of effective field and it satisfies the following relation: 0.36<RI.sub.min<0.65.

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.

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.

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 preset distances 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.

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 preset distances 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.

An optical lens assembly with a first optical axis and a second optical axis parallel to the first optical axis, includes a first element group located on an object side of the optical lens assembly; a second element group located on an image side of the optical lens assembly; and a light guide element disposed at the position where the first and second optical axes pass. The first and second element groups being located on the same side of the light guide element. The optical lens assembly has a long focal length, a compact size and a relatively higher illumination when satisfying a specific condition.

An optical lens assembly with a first optical axis and a second optical axis parallel to the first optical axis, includes a first element group located on an object side of the optical lens assembly; a second element group located on an image side of the optical lens assembly; and a light guide element disposed at the position where the first and second optical axes pass. The first and second element groups being located on the same side of the light guide element. The optical lens assembly has a long focal length, a compact size and a relatively higher illumination when satisfying a specific condition.

An optical imaging lens includes a first lens element, a second lens, an aperture stop, a third lens element and a fourth lens element from an object side to an image side in order along an optical axis, and each lens element has an object-side surface and an image-side surface. An optical axis of the image-side surface of the first lens element is convex and an optical axis of the image-side surface of the fourth lens element is concave. HFOV stands for the half field of view of the entire optical imaging lens and TTL is a distance from the object-side surface of the first lens element to an image plane along the optical axis to satisfy HFOV/TTL1.500 /mm.