BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to an optical imaging lens. Specifically speaking, the present invention is directed to an optical imaging lens for use in a portable electronic device such as a mobile phone, a camera, a tablet personal computer, or a personal digital assistant (PDA) for taking pictures or for recording videos.

2. Description of the Prior Art

The specification of the consumer's electronic products change all the time, so do the key components of those electronic products such as an optical imaging lens develop to have diverse applications beyond taking pictures or recording videos only. Even a telescopic function is introduced to go with wide angle lens to have optical zoom function. The longer the total length of the telescopic lens is, the higher the zoom ratio.

However, with the increase of the total length of the telescopic lens, a larger F number results in a small flux. Accordingly, it is still needed to have larger total length of the telescopic lens with a smaller F number, to keep the imaging quality, to make the fabrication easier and to improve the yield. The above issues are always important to research in this filed.

SUMMARY OF THE INVENTION

In the light of the above, examples in the present invention accordingly propose an optical imaging lens which is not only able to increase the total length of the lens, to ensure the imaging quality, to have a smaller F number, to keep a good optical function, and is technically possible. The optical imaging lens of five lens elements of examples in the present invention from an object side toward an image side in order along an optical axis has a first lens element, a second lens element, a third lens element, a fourth lens element and a fifth lens element. Each lens element from the first lens element to the fifth lens element respectively has an object-side surface which faces toward an object side to allow an imaging ray to pass through as well as an image-side surface which faces toward an image side to allow the imaging ray to pass through.

The image-side surface of the first lens element has a concave portion in a vicinity of the optical-axis. The object-side surface of the second lens element has a convex portion in a vicinity of the optical-axis. The image-side surface of the third lens element has a concave portion in a vicinity of the optical-axis. The fifth lens element has negative refractive power and a thickness of the fifth lens element along the optical-axis is larger than that of the second lens element. The optical imaging lens exclusively has the above five lens elements with refractive power. EFL is an effective focal length of the optical imaging lens, TTL is a distance from the object-side surface of the first lens element to an image plane, ALT is a total thickness of all five lens elements along the optical-axis, the second lens element has a second lens element thickness T2 and an air gap G34 is between the third lens element and the fourth lens element along the optical axis to satisfy TTL/EFL≤1.000, TTL/G34≤12.000 and ALT/T2≤12.900.

In the optical imaging lens of five lens elements of embodiments in the present invention, the fifth lens element has a fifth lens element thickness T5 along the optical axis and an air gap G45 is between the fourth lens element and the fifth lens element along the optical axis to satisfy (G45+T5)/T2≤4.800.

The optical imaging lens of five lens elements of examples in the present invention satisfies TTL/(G45+T5)≤7.200.

In the optical imaging lens of five lens elements of examples in the present invention, the fourth lens element has a fourth lens element thickness T4 along the optical axis to satisfy T4/G45≤3.600.

In the optical imaging lens of five lens elements of examples in the present invention, AAG is a sum of all four air gaps between each lens element from the first lens element to the fifth lens element to satisfy AAG/T2≤9.000.

In the optical imaging lens of five lens elements of examples in the present invention, BFL is a distance between the image-side surface of the fifth lens element and the image plane along the optical axis and the third lens element has a third lens element thickness T3 along the optical axis to satisfy BFL/T3≤5.600.

In the optical imaging lens of five lens elements of examples in the present invention, TL is a distance between the object-side surface of the first lens element and the image-side surface of the fifth lens element along the optical axis to satisfy TL/T3≤17.000.

The optical imaging lens of five lens elements of examples in the present invention satisfies AAG/T3≤8.000.

The optical imaging lens of five lens elements of examples in the present invention satisfies TL/T5≤15.000.

The optical imaging lens of five lens elements of examples in the present invention satisfies AAG/T5≤8.000.

In the optical imaging lens of five lens elements of examples in the present invention, the first lens element has a first lens element thickness T1 along the optical axis to satisfy TTL/T1≤9.000.

The optical imaging lens of five lens elements of examples in the present invention satisfies ALT/T1≤3.600.

The optical imaging lens of five lens elements of examples in the present invention satisfies ALT/G34≤3.900.

The optical imaging lens of five lens elements of examples in the present invention satisfies EFL/G34≤7.300.

The optical imaging lens of five lens elements of examples in the present invention satisfies EFL/BFL≤5.500.

The optical imaging lens of five lens elements of examples in the present invention satisfies BFL/T4≤5.100.

The optical imaging lens of five lens elements of examples in the present invention satisfies TL/BFL≤4.200.

The optical imaging lens of five lens elements of examples in the present invention satisfies, an air gap G12 is between the first lens element and the second lens element along the optical axis and an air gap G23 is between the second lens element and the third lens element along the optical axis to satisfy (T1+G12+T2+G23+T3)/T5≤4.300.

The optical imaging lens of five lens elements of examples in the present invention satisfies (T1+G12+T2+G23+T3)/T1≤2.700.

The optical imaging lens of five lens elements of examples in the present invention satisfies (T1+G12+T2+G23+T3)/G34≤2.500.

These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.

