An imaging optical system includes three lens elements. The three lens elements, in order from an object side to an image side, are a first lens element having an object-side surface facing the object side and an image-side surface facing the image side, a second lens element having an object-side surface facing the object side and an image-side surface facing the image side, and a third lens element having an object-side surface facing the object side and an image-side surface facing the image side. The third lens element has positive refractive power, the imaging optical system has a total of three lens elements, and there are air gaps between paraxial regions of the first lens element, the second lens element and the third lens element.

An imaging lens consisting of, in order from an object side to an image side: a first lens group that has a positive refractive power; a second lens group that has a positive refractive power; and a third lens group, wherein: during focusing, the second lens group moves along an optical axis, and the first lens group and the third lens group remain stationary with respect to an image plane, the second lens group includes a stop, an Lp1 lens, which is a positive lens, is disposed closest to the object side in the second lens group, an Lp2 lens, which is a positive lens, is disposed closest to the image side in the second lens group.

Compact folded lens systems are described that may be used in small form factor cameras. Lens systems are described that may include three lens elements with refractive power, with a light folding element such as a prism, located between a first lens element on the object side of the lens system and a second lens element, that redirects the light refracted from the first lens element from a first axis onto a second axis on which the other lens elements and a photosensor are arranged. The lens systems may include an aperture stop located behind the front vertex of the lens system, for example at the first lens element, and an optional infrared filter, for example located between the last lens element and a photosensor.

A three-piece infrared single wavelength projection lens system, in order from an image side to an image source side: a stop; a first lens element with a positive refractive power having an image-side surface being convex near an optical axis and an image source-side surface being concave near the optical axis; a second lens element with a negative refractive power having an image source-side surface being concave near the optical axis; and a third lens element with a positive refractive power having an image-side surface being concave near the optical axis and an image source-side surface being convex near the optical axis. Such arrangements can provide a three-piece infrared single wavelength projection lens system with better image sensing function.

According to an embodiment of the disclosure, a lens assembly and/or an electronic device including the same may include an image sensor and three lenses sequentially arranged along an optical axis from an object side to an image sensor side. In the three lenses, a first lens disposed on the object side may include an object side surface convex toward the object and an image sensor side surface convex toward the image sensor while having positive power, a second lens may include an object side surface concave toward the image sensor while having negative power, and a third lens may have negative power. The lens assembly may satisfy the condition below:

[00001]$0.1\le L12/L23\le 0.4$

wherein “L12” may be a distance or air gap between the first lens and the second lens, and “L23” may be a distance or air gap between the second lens and the third lens.

The present disclosure provides an optical imaging lens assembly, comprising, sequentially along an optical axis from an object side to an image side: a first lens, having a negative refractive power, an object-side surface of the first lens being a concave surface; a second lens, having a positive refractive power, an image-side surface of the second lens being a convex surface; and a third lens, having a refractive power, an image-side surface of the third lens being a concave surface. An effective focal length f1 of the first lens and an effective focal length f of the optical imaging lens assembly satisfy: −4<f1/f<−2. A maximal field-of-view FOV of the optical imaging lens assembly and the effective focal length f of the optical imaging lens assembly satisfy: 1 mm<tan(FOV/2)×f<2 mm.

An optical lens assembly includes, in order from the object side to the image side: a stop, a first lens element, a second lens element, a third lens element, and an infrared bandpass filter. An entrance pupil diameter of the optical lens assembly is EPD, a half of a maximum field of view of the optical lens assembly is HFOV, and the following condition is satisfied: 0.59<EPD/tan(HFOV)<1.33.

An optical imaging system includes a lens group including at least one lens forming a first optical axis; and an optical path converter reflecting light emitted from the lens group to form an image on an imaging plane. In the optical imaging system, a maximum distance from an object side surface of a frontmost lens, disposed closest to an object side, among the lens group, to the imaging plane, in a first optical axis direction is 11.0 mm or less.

An imaging lens system includes an optical path folding member including a forwardmost reflective surface disposed closest to an object side, a rearmost reflective surface disposed closest to an imaging plane, and a rear reflective surface disposed to form an acute angle with the rearmost reflective surface and configured to reflect light reflected by the rearmost reflective surface to the imaging plane, and a first lens group disposed on an object side of the forwardmost reflective surface or an image side of the forwardmost reflective surface, wherein an angle between a first virtual plane including the forwardmost reflective surface and a second virtual plane including the rearmost reflective surface is 15 to 27 degrees.

An objective lens assembly includes a first lens group configured to have a positive refractive power, the first lens group being positioned to receive visible light along an optical path extending therethrough. The objective lens assembly further includes a second lens group configured to have a negative refractive power, the second lens group being positioned along the optical path to receive the visible light from the first lens group. The objective lens assembly further includes a center lens disposed between the first lens group and the second lens group and an aperture stop centered along the optical path and positioned in front of the first lens group to direct visible light from a scene to the first lens group.