RELATED APPLICATIONS

This application claims priority to Taiwan Application 107137600, filed on Oct. 24, 2018, which is incorporated by reference herein in its entirety.

BACKGROUND

Technical Field

The present disclosure relates to an imaging lens system, an image capturing unit and an electronic device, more particularly to an imaging lens system and an image capturing unit applicable to an electronic device.

Description of Related Art

With the development of semiconductor manufacturing technology, the performance of image sensors has been improved, and the pixel size thereof has been scaled down. Therefore, featuring high image quality becomes one of the indispensable features of an optical system nowadays.

Furthermore, due to the rapid changes in technology, electronic devices equipped with optical systems are developed towards multi-functionality for various applications, and therefore the functionality requirements for the optical systems have been increasing. However, it is yet difficult for a conventional optical system to obtain a balance among the requirements such as high image quality, low sensitivity, proper aperture size, miniaturization or a desirable field of view. Accordingly, there is a need for an optical system that satisfies the aforementioned requirements.

SUMMARY

According to one aspect of the present disclosure, an imaging lens system includes eight lens elements. The eight lens elements are, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element. Each of the eight lens elements has an object-side surface facing toward the object side and an image-side surface facing toward the image side. The first lens element has positive refractive power. At least one lens element of the imaging lens system has at least one lens surface having at least one inflection point. The imaging lens system has a total of eight lens elements. When a minimum value among Abbe numbers of all lens elements of the imaging lens system is Vmin, half of a maximum field of view of the imaging lens system is HFOV, a focal length of the imaging lens system is f, a focal length of the first lens element is f1, an entrance pupil diameter of the imaging lens system is EPD, an axial distance between the image-side surface of the eighth lens element and an image surface is BL, and an axial distance between the object-side surface of the first lens element and the image-side surface of the eighth lens element is TD, the following conditions are satisfied:
8.0<Vmin<22.5;
5.0 [deg.]<HFOV<25.0 [deg.];
0.80<f/EPD<2.20;
0<BL/TD<0.25; and
0.32<f/f1<3.80.

According to another aspect of the present disclosure, an image capturing unit includes the aforementioned imaging lens system and an image sensor, wherein the image sensor is disposed on the image surface of the imaging lens system.

According to still another aspect of the present disclosure, an electronic device includes at least two image capturing units, and the at least two image capturing units face the same side. The at least two image capturing units include a first image capturing unit and a second image capturing unit. The first image capturing unit includes the aforementioned imaging lens system and a first image sensor, and the first image sensor is disposed on the image surface of the imaging lens system. The second image capturing unit includes an optical lens assembly and a second image sensor, and the second image sensor is disposed on an image surface of the optical lens assembly. A field of view of the first image capturing unit and a field of view of the second image capturing unit are different from each other by at least 20 degrees.

According to yet another aspect of the present disclosure, an imaging lens system includes eight lens elements. The eight lens elements are, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element. Each of the eight lens elements has an object-side surface facing toward the object side and an image-side surface facing toward the image side. At least one lens element of the imaging lens system has at least one lens surface having at least one inflection point. The imaging lens system has a total of eight lens elements. When an Abbe number of the eighth lens element is V8, half of a maximum field of view of the imaging lens system is HFOV, a focal length of the imaging lens system is f, an entrance pupil diameter of the imaging lens system is EPD, and an axial distance between the object-side surface of the first lens element and an image surface is TL, the following conditions are satisfied:
8.0<V8<24.5;
5.0 [deg.]<HFOV<30.0 [deg.];
0.80<f/EPD<2.20; and
0.50<TL/f<1.30.

According to yet still another aspect of the present disclosure, an imaging lens system includes eight lens elements. The eight lens elements are, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element. Each of the eight lens elements has an object-side surface facing toward the object side and an image-side surface facing toward the image side. At least one lens element of the imaging lens system has at least one lens surface having at least one inflection point. The imaging lens system has a total of eight lens elements. When a minimum value among Abbe numbers of all lens elements of the imaging lens system is Vmin, an axial distance between the object-side surface of the first lens element and an image surface is TL, a focal length of the imaging lens system is f, an axial distance between the image-side surface of the eighth lens element and the image surface is BL, and an axial distance between the object-side surface of the first lens element and the image-side surface of the eighth lens element is TD, the following conditions are satisfied:
8.0<Vmin<20.0;
0.50<TL/f<1.10; and
0<BL/TD<0.30.

