An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, sequentially disposed from an object side to an imaging plane. The optical imaging system satisfies the expression BFL/f < 0.15, where BFL represents a distance from an image-side surface of the eighth lens to an imaging plane of an image sensor and f represents an overall focal length of the optical imaging system.

An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, sequentially disposed from an object side to an imaging plane. The optical imaging system satisfies the expression BFL/f < 0.15, where BFL represents a distance from an image-side surface of the eighth lens to an imaging plane of an image sensor and f represents an overall focal length of the optical imaging system.

An imaging lens includes a first lens having positive refractive power; a second lens having positive refractive power; a third lens having negative refractive power; a fourth lens having positive refractive power; a fifth lens; a sixth lens; a seventh lens; an eighth lens; and a ninth lens having negative refractive power, arranged in this order from an object side to an image plane side. The ninth lens is formed in a shape so that a surface thereof on the image plane side has an aspherical shape having an inflection point.

In an optical imaging lens, a first lens element has negative refracting power, a second lens element has negative refracting power, an optical axis region of the object-side surface of the third lens element is concave, an optical axis region of the object-side surface of the fourth lens element is convex, an optical axis region of the object-side surface of the fifth lens element is convex, a sixth lens element is arranged to be a lens element in a second order from an image-side to an object-side and a seventh lens element is arranged to be a lens element in a first order from the image-side to the object-side to satisfy: (G23+T3+T4+G45)/L57≥2.700 and 1+2≤80.000.

An optical imaging lens module is provided, the optical imaging lens module may include a first lens barrel and a second lens barrel, positioned in an order from an image side to an object side along an optical axis; an optical imaging lens, comprising a first lens element group and a second lens element group, disposed in the first lens barrel and the second lens barrel respectively; an actuating unit, disposed on an external side of the second lens barrel to make the second lens barrel to be a movable barrel, which can move along the optical axis relative to the first lens barrel. The optical imaging lens may satisfy EFL/TTL≥0.850, in which a system focal length is represented by EFL, and a distance from an object-side surface of the lens element having refracting power and closest to the object side to an imaging plane along the optical axis is represented by TTL.

An optical imaging lens module is provided, the optical imaging lens module may include a first lens barrel and a second lens barrel, positioned in an order from an image side to an object side along an optical axis; an optical imaging lens, comprising a first lens element group and a second lens element group, disposed in the first lens barrel and the second lens barrel respectively; an actuating unit, disposed on an external side of the second lens barrel to make the second lens barrel to be a movable barrel, which can move along the optical axis relative to the first lens barrel. The optical imaging lens may satisfy EFL/TTL≥0.850, in which a system focal length is represented by EFL, and a distance from an object-side surface of the lens element having refracting power and closest to the object side to an imaging plane along the optical axis is represented by TTL.

A photographing optical lens assembly includes five lens elements with refractive power, in order from an object side to an image side. The first lens element with refractive power has a convex object-side surface. The second lens element with positive refractive power has an object-side surface and an image-side surface both being aspheric. The third lens element has positive refractive power. The fourth lens element with refractive power has a concave object-side surface. The fifth lens element with refractive power has an object-side surface and a concave image-side surface with at least one inflection point, both the object-side surface and the image-side surface being aspheric.

A photographing optical lens assembly includes five lens elements with refractive power, in order from an object side to an image side. The first lens element with refractive power has a convex object-side surface. The second lens element with positive refractive power has an object-side surface and an image-side surface both being aspheric. The third lens element has positive refractive power. The fourth lens element with refractive power has a concave object-side surface. The fifth lens element with refractive power has an object-side surface and a concave image-side surface with at least one inflection point, both the object-side surface and the image-side surface being aspheric.

Present embodiments provide for a mobile device and an optical imaging lens thereof. The optical imaging lens comprises five lens elements positioned sequentially from an object side to an image side. Through controlling the convex or concave shape of the surfaces and/or the refracting power of the lens elements, the optical imaging lens shows better optical characteristics and the total length of the optical imaging lens is shortened.

A head-up display includes a display device and a projection optical system; the projection optical system includes first and second optical elements arranged in order of an optical path from the image; and when optical paths corresponding to an upper end and a lower end of the virtual image are defined as an upper ray and a lower ray, respectively, and a diverging effect and a converging effect are defined as being negative and positive, respectively, the first and the second optical elements satisfy conditional expressions P_u1−P_l1<0 and P_u2−P_l2>0 (where P_u1 denotes a local power of the first optical element acting on the upper ray, P_l1 denotes a local power of the first optical element acting on the lower ray, P_u2 denotes a local power of the second optical element acting on the upper ray, P_l2 denotes a local power of the second optical element acting on the lower ray).