Imaging lens system, image acquisition unit and electronic device

Abstract

An imaging lens system comprising two lens groups (G1, G2), wherein the two lens groups (G1, G2) are a first lens group (G1) and a second lens group (G2) in the order from an object side to an image side along a light path, each lens element of the two lens groups (G1, G2) has an object-side surface facing the object side and an image-side surface facing the image side, and a total number of lens groups of the imaging lens system is two; wherein the imaging lens system has a first state corresponding to an infinite object distance; wherein the imaging lens system in the first state has a first long focal end state corresponding to a long focal end and a first short focal end state corresponding to a short focal end during a zooming operation, and at least one lens group of the two lens groups (G1, G2) moves along a direction parallel to an optical axis during the zooming operation; wherein at least one of the object-side surface and the image-side surface of at least one lens element of the two lens groups (G1, G2) has at least one inflection point (P) in an off-axis region thereof; wherein the imaging lens system comprises, in order from the object side to the image side along the optical path, a first lens element (E1), a second lens element (E2), a third lens element (E3), and a fourth lens element (E4), and a lens element having a maximum central thickness among the imaging lens system is the third lens element (E3) or the fourth lens element (E4); wherein a focal length of the imaging lens system in the first state with a long focal point end is fLf, a focal length of the imaging lens system in the first state with a short focal point end is fSf, a focal length of the first lens group (G1) is fG1, a focal length of the second lens group (G2) is fG2, a radius of curvature of the image-side surface of the third lens element (E3) is R6, a radius of curvature of the object-side surface of the fourth lens element (E4) is R7, and the following conditions are satisfied: 1.20 < fLf / fSf < 2.00 ; − 0,80 < fG1 / fG2 < − 0,20 ; und − 2,00 < R6 / R7 < − 0,65.

Description

Technical area

[0001] The present disclosure relates to an imaging lens system, an image capture unit, and an electronic device, particularly to an imaging lens system and an image capture unit that can be used in an electronic device. Description of the state of the art

[0002] With the development of semiconductor manufacturing technology, the performance of image sensors has improved and their pixel size has been downscaled. Therefore, high image quality is one of the essential features of an optical system today.

[0003] Furthermore, due to rapid technological change, electronic devices equipped with optical systems are tending toward multifunctionality for various applications, which has increased the requirements for the functionality of the optical systems. However, it is difficult to achieve a balance between requirements such as high image quality, low sensitivity, a suitable aperture size, miniaturization, and a desirable field of view with a conventional optical system.

[0004] Especially in recent years, electronic devices and other electronic products have become increasingly lighter and thinner, making it difficult for traditional optical lenses to simultaneously meet the requirements of high specifications and compactness, especially for small lenses with large apertures or telephoto lenses. Traditional telephoto lenses can no longer meet the technological requirements and therefore have problems such as excessively large overall length, excessively small aperture, insufficient quality, and lack of compactness. Therefore, other optical features must be introduced to solve the above problems in order to meet the requirements.

[0005] To enhance medium- to long-range photography, some current mobile phones also use fixed-focal-length telephoto lenses combined with digital zoom algorithms. However, the resulting visual effects do not originate from true optical zoom, resulting in a deterioration in image quality. Alternatively, other mobile phones achieve short- and long-distance zoom effects through the interaction of a variety of lenses with different focal lengths. However, their disadvantages include image judder when switching between lenses and variations in the amount of incident light and color consistency, resulting in a poor photography experience. Furthermore, the use of multiple lenses significantly increases the space required within an electronic product. SUMMARY

[0006] According to one aspect of the present disclosure, an imaging lens system includes two lens groups. The two lens groups are, in order from an object side to an image side along a light path, a first lens group and a second lens group. Each of the lens elements of the two lens groups has an object-side surface facing the object side and an image-side surface facing the image side. The total number of lens groups of the imaging lens system is two.

[0007] Preferably, the imaging lens system has a first state corresponding to an infinite object distance.

[0008] Preferably, the imaging lens system has a first long focal point end state corresponding to a long focal point end and a first short focal point end state corresponding to a short focal point end during a zooming operation. Preferably, at least one lens group of the two lens groups moves along a direction parallel to an optical axis during the zooming operation.

[0009] Preferably, at least one of the object-side surface and the image-side surface of at least one lens element of the two lens groups has at least one inflection point in an off-axis region thereof.

[0010] Preferably, the imaging lens system comprises, in order from the object side to the image side along the optical path, a first lens element, a second lens element, a third lens element, and a fourth lens element, and a lens element having a maximum central thickness among the imaging lens system is the third lens element or the fourth lens element.

[0011] When a focal length of the imaging lens system in the first state with a long focal point end is fLf, a focal length of the imaging lens system in the first state with a short focal point end is fSf, a focal length of the first lens group is fG1, a focal length of the second lens group is fG2, a radius of curvature of the image-side surface of the third lens element is R6, and a radius of curvature of the object-side surface of the fourth lens element is R7, the following conditions are preferably satisfied: 1.20 <fLf / fSf<2,00; −0.80 <fG1 / fG2<−0,20; und −2.00 <R6 / R7<−0,65.

[0012] According to another aspect of the present disclosure, an imaging lens system includes two lens groups. The two lens groups are, in order from an object side to an image side along a light path, a first lens group and a second lens group. Each of the lens elements of the two lens groups has an object-side surface facing the object side and an image-side surface facing the image side. The total number of lens groups of the imaging lens system is two.

[0013] Preferably, the imaging lens system has a first state that coincides with an infinite object distance.

[0014] Preferably, the imaging lens system has a first long focal point end state corresponding to a long focal point end and a first short focal point end state corresponding to a short focal point end during a zooming operation. Preferably, at least one lens group of the two lens groups moves along a direction parallel to an optical axis during the zooming operation.

[0015] Preferably, at least one of the object-side surface and the image-side surface of at least one lens element of the two lens groups has at least one inflection point in an off-axis region thereof.

[0016] Preferably, a lens element having a maximum central thickness among the imaging lens system is a lens element of the first lens group closest to the image side or a lens element of the second lens group closest to the object side.

[0017] When a focal length of the imaging lens system in the first state with a long focal point end is fLf, a focal length of the imaging lens system in the first state with a short focal point end is fSf, a focal length of the first lens group is fG1, a focal length of the second lens group is fG2, half of a maximum field of view of the imaging lens system in the first state with a short focal point end is HFOVSf, a radius of curvature of the image-side surface of the lens element of the first lens group of the imaging lens system closest to the image side is RG1i, and a radius of curvature of the image-side surface of the lens element of the first lens group of the imaging lens system closest to the object side is RG2o, the following conditions are preferably satisfied: 1.20 <fLf / fSf<2,00; −0.80 <fG1 / fG2<−0,20; 3.00 degrees <HFOVSf<35,00 Grad; und −2.00 <RG1i / RG2o<−0,65.

[0018] According to another aspect of the present disclosure, an imaging lens system includes two lens groups. The two lens groups are, in order from an object side to an image side along a light path, a first lens group and a second lens group. Each of the lens elements of the two lens groups has an object-side surface facing the object side and an image-side surface facing the image side. The total number of lens groups of the imaging lens system is two.

[0019] Preferably, the imaging lens system has a first state corresponding to an infinite object distance and a second state corresponding to a finite object distance.

[0020] Preferably, the imaging lens system performs a zoom operation to change the first state to the second state thereof during movement of an imaged object from the infinite object distance to the finite object distance.

[0021] Preferably, the imaging lens system has a first long focal point end state corresponding to a long focal point end and a first short focal point end state corresponding to a short focal point end during a zooming operation. Preferably, at least one lens group of the two lens groups moves along a direction parallel to an optical axis during the focusing process.

[0022] Preferably, at least one of the object-side surface and the image-side surface of at least one lens element of the two lens groups has at least one inflection point in an off-axis region thereof.

[0023] Preferably, the imaging lens system comprises, in order from the object side to the image side along the optical path, a first lens element, a second lens element, a third lens element, and a fourth lens element, and a lens element having a maximum central thickness among the imaging lens system is the third lens element or the fourth lens element.

[0024] When a focal length of the imaging lens system in the first state with a long focal point end is fLf, a focal length of the imaging lens system in the first state with a short focal point end is fSf, a focal length of the first lens group is fG1, a focal length of the second lens group is fG2, a radius of curvature of the image-side surface of the third lens element is R6, and a radius of curvature of the object-side surface of the fourth lens element is R7, the following conditions are preferably satisfied: 1.20 <fLf / fSf<2,00; −0.80 <fG1 / fG2<−0,20; und −2.00 <R6 / R7<−0,65.

[0025] According to another aspect of the present disclosure, an image acquisition unit comprises one of the aforementioned imaging lens systems and an image sensor, wherein the image sensor is arranged on an image surface of the imaging lens system.

[0026] According to another aspect of the present disclosure, an electronic device comprises a first image capture unit and a second image capture unit, wherein the first image capture unit comprises the aforementioned image capture unit. A maximum field of view of the first image capture unit ranges from 3 degrees to 35 degrees. The second image capture unit is arranged on the same side of the electronic device as the first image capture unit.

[0027] A maximum field of view of the second image acquisition unit ranges from 35 degrees to 70 degrees. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The disclosure can be better understood from the following detailed description of the embodiments with reference to the accompanying drawings: Fig. 1 is a schematic view of an image acquisition unit in a first short focal point end state and in a first long focal point end state according to the first embodiment of the present disclosure; Fig. 2 shows spherical aberration curves, astigmatic field curves, and a distortion curve of the image pickup unit in the first state with a short focal point end according to the first embodiment; Fig. 3 shows spherical aberration curves, astigmatic field curves, and a distortion curve of the image pickup unit in the first state with a long focal point end according to the first embodiment; Fig.4 is a schematic view of an image acquisition unit in each of the first short focal end state and the first long focal end state according to the second embodiment of the present disclosure; Fig. 5 shows spherical aberration curves, astigmatic field curves, and a distortion curve of the image pickup unit in the first state with a short focal point end according to the second embodiment; Fig. 6 shows spherical aberration curves, astigmatic field curves, and a distortion curve of the image pickup unit in the first state with a long focal point end according to the second embodiment; Fig. 7 is a schematic view of an image acquisition unit in a first short focal point end state and in a first long focal point end state according to the third embodiment of the present disclosure; Fig.8 shows spherical aberration curves, astigmatic field curves, and a distortion curve of the image pickup unit in the first state with a short focal point end according to the third embodiment; Fig. 9 shows spherical aberration curves, astigmatic field curves, and a distortion curve of the image pickup unit in the first state with a long focal point end according to the third embodiment; Fig. 10 is a perspective view of an image acquisition unit according to the fourth embodiment of the present disclosure; Fig. 11 is a perspective view of an electronic device according to the fifth embodiment of the present disclosure; Fig. 12 is another perspective view of the electronic device in Fig. 11; Fig. 13 is a perspective view of an electronic device according to the sixth embodiment of the present disclosure; Fig. 14 is another perspective view of the electronic device in Fig. 13; Fig. 15 is a block diagram of the electronic device in Fig. 13; Fig. 16 is a perspective view of an electronic device according to the seventh embodiment of the present disclosure; Fig. 17 is a schematic view showing inflection points and critical points of lens elements of an image sensing unit in the first short focal point end state according to the first embodiment of the present disclosure; Fig. 18 shows a schematic view of a configuration of a reflective element in an imaging lens system according to an embodiment of the present disclosure; Fig.19 shows a schematic view of another configuration of a reflective element in an imaging lens system according to an embodiment of the present disclosure; Fig. 20 shows a schematic view of another configuration of a reflective element in an imaging lens system according to an embodiment of the present disclosure; Fig. 21 shows a schematic view of a configuration of two reflective elements in an imaging lens system according to an embodiment of the present disclosure; and Fig. 22 shows a schematic view of another configuration of two reflective elements in an imaging lens system according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] An imaging lens system may comprise, in order from an object side to an image side along a light path, a first lens element, a second lens element, a third lens element, and a fourth lens element.

[0030] The imaging lens system may include two lens groups. The two lens groups may be a first lens group and a second lens group in order from the object side to the image side along the optical path. The two lens groups may include six lens elements. The six lens elements may be, in order from the object side to the image side along the optical path, the first lens element, the second lens element, the third lens element, the fourth lens element, a fifth lens element, and a sixth lens element. The total number of lens groups of the imaging lens system may be two. The first lens group may include the first lens element, the second lens element, and the third lens element, and the second lens group may include the fourth lens element, the fifth lens element, and the sixth lens element.Each of the lens elements of the two lens groups can have an object-side surface facing the object side and an image-side surface facing the image side. Therefore, configuring the imaging lens system with a total of two lens groups achieves a good balance between overall size, zoom ratio, object distance range, moving focus, image quality, and assembly effort, thus achieving optical zoom and optical focusing for medium- to long-range imaging.

[0031] The imaging lens system may have a first state corresponding to an infinite object distance and a second state corresponding to a finite object distance, wherein the first state may refer to a state of the imaging lens system with an imaged object at an infinite distance (the infinite object distance), and the second state may refer to a state of the imaging lens system with an imaged object at a finite distance (the finite object distance). In the present disclosure, the finite object distance may refer to a position of an imaged object that is obviously closer to the imaging lens system than infinity. Furthermore, the infinite object distance refers to an axial distance between an imaged object and the object-side surface of a lens element of the imaging lens system that is closest to the object side (e.g.,the first lens element) that is equal to or greater than 1000 meters. Furthermore, the finite object distance refers to an axial distance between an imaged object and the object-side surface of a lens element of the imaging lens system closest to the object side (e.g., the first lens element) that is equal to or less than 5 meters. When an imaged object at infinite object distance moves to finite object distance, the imaging lens system can perform a focusing process to change its first state to its second state. Conversely, when an imaged object at finite object distance moves to infinite object distance, the imaging lens system can also perform the focusing process to change its second state to its first state.At least one lens group of the two lens groups can move along a direction parallel to an optical axis during the focusing process. Furthermore, the second lens group can move along the direction parallel to the optical axis during the focusing process. Therefore, this is advantageous for preventing the overall lens structure of the imaging lens system from expanding or shrinking toward or away from the object side due to the focusing process, thereby improving the operability and robustness of the lens and simplifying the optical design and mechanism thereof. Furthermore, all lens elements of each of the first lens group and the second lens group can exhibit no relative movement with respect to each other during the focusing process. Therefore, this is advantageous for simplifying the mechanism thereof.

[0032] The imaging lens system in the first state may have a first long focal point end state corresponding to a long focal point end and a first short focal point end state corresponding to a short focal point end during a zooming operation. At least one lens group of the two lens groups may move along a direction parallel to the optical axis during the zooming operation. See Fig. 1, which is a schematic view of an image acquisition unit in a first short focal point end state and in a first long focal point end state, respectively, according to the first embodiment of the present disclosure. The upper part of Fig. 1 shows the imaging lens system in the first state with short focal point end, and the lower part of Fig.1 shows the imaging lens system in the first state with a long focal point end. Furthermore, the second lens group can move along the direction parallel to the optical axis during the zooming operation. Therefore, this is advantageous for preventing the overall lens structure of the imaging lens system from expanding or shrinking toward or away from the object side due to the zooming operation, thereby improving the operability and robustness of the lens and simplifying the optical design and mechanism thereof. Furthermore, all lens elements of each of the first lens group and the second lens group can exhibit no relative movement to each other during the zooming operation. Therefore, this is advantageous for simplifying the mechanism thereof.

[0033] Similarly, in the second state, the imaging lens system may have a second long focal end state corresponding to the long focal end and a second short focal end state corresponding to the short focal end during the zooming operation.

[0034] A lens element with the maximum central thickness among the imaging lens system may be a lens element of the first lens group closest to the image side or a lens element of the second lens group closest to the object side. Therefore, it is advantageous to increase the refractive power of the lens element of the first lens group closest to the image side or the refractive power of the lens element of the second lens group closest to the object side, thereby reducing the lens pitch between the lens element of the first lens group closest to the image side and the lens element of the second lens group closest to the object side in both the first state and the second state, thus reducing the total path length of the imaging lens system.Furthermore, among the imaging lens systems, the lens element having the maximum central thickness may be the third lens element or the fourth lens element. Therefore, it is advantageous to increase the refractive power of the third lens element or the refractive power of the fourth lens element, thereby reducing the lens pitch between the third lens element and the fourth lens element, and thus reducing the total path length of the imaging lens system. In one aspect of the present application, the lens element of the first lens group closest to the image side may be the third lens element. In one aspect of the present application, the lens element of the second lens group closest to the object side may be the fourth lens element.

[0035] The lens element of the first lens group closest to the image side may have a positive refractive power. Therefore, it is advantageous to balance the refractive power of the first lens group and the refractive power of the lens element of the second lens group closest to the object side in order to control the spatial distribution of the optical path at different focal lengths of the imaging lens system, thereby improving the image quality at different focal lengths.

[0036] The third lens element may have a positive refractive power. Therefore, it is advantageous to balance the refractive powers of the second and fourth lens elements on the object side and the image side of the third lens element, respectively, thereby increasing the light convergence capability between the second lens element and the fourth lens element and correcting aberrations.

[0037] The sixth lens element may have a negative refractive power. Therefore, it is advantageous for balancing the refractive power of the imaging lens system at one image end thereof, increasing the convergence quality of light from different fields of view onto an image surface of the imaging lens system, and correcting aberrations. The image-side surface of the sixth lens element may be concave in a paraxial region thereof. Therefore, it is advantageous for assisting in balancing the back focal length of the imaging lens system while correcting off-axis aberrations.

[0038] According to the present disclosure, at least one of the object-side surface and the image-side surface of at least one lens element of the two lens groups may have at least one inflection point in an off-axis region thereof. Therefore, this is advantageous for increasing optical design flexibility to correct astigmatism. Furthermore, the image-side surface of the sixth lens element may have at least one inflection point in an off-axis region thereof. Therefore, this is advantageous for controlling the angle of light passing through the periphery of the image-side surface of the sixth lens element, thereby maintaining the optical illuminance and preventing the generation of excessive aberrations due to an excessively large deflection angle of the light. See Fig.17 is a schematic view showing the inflection points P of the image-side surface of the first lens element E1, the object-side surface of the second lens element E2, the image-side surface of the second lens element E2, the object-side surface of the third lens element E3, the image-side surface of the fourth lens element E4, the object-side surface of the fifth lens element E5, the image-side surface of the fifth lens element E5, the object-side surface of the sixth lens element E6, and the image-side surface of the sixth lens element E6 of the image sensing unit in the first short-focus-end state according to the first embodiment of the present disclosure.The inflection points of the image-side surface of the first lens element, the object-side surface of the second lens element, the image-side surface of the second lens element, the object-side surface of the third lens element, the image-side surface of the fourth lens element, the object-side surface of the fifth lens element, the image-side surface of the fifth lens element, the object-side surface of the sixth lens element and the image-side surface of the sixth lens element in . Fig. 17 are merely exemplary. Each of the object-side surfaces and the image-side surfaces of the lens elements in the first and other embodiments of the present disclosure may also have one or more inflection points in an off-axis region thereof.

[0039] According to the present disclosure, at least one of the object-side surfaces and the image-side surfaces of at least one lens element of the two lens groups may have at least one critical point in an off-axis region thereof. Therefore, this is advantageous for improving the ability to correct aberrations in the peripheral image. See Fig.17 is a schematic view of the critical points C of the image-side surface of the first lens element E1, the object-side surface of the second lens element E2, the image-side surface of the second lens element E2, the object-side surface of the third lens element E3, the image-side surface of the fourth lens element E4, the object-side surface of the fifth lens element E5, and the object-side surface of the sixth lens element E6 of the image sensing unit in the first short-focus state according to the first embodiment of the present disclosure.The critical points of the image-side surface of the first lens element, the object-side surface of the second lens element, the image-side surface of the second lens element, the object-side surface of the third lens element, the image-side surface of the fourth lens element, the object-side surface of the fifth lens element, the image-side surface of the fifth lens element and the object-side surface of the sixth lens element in . Fig. 17 are merely exemplary. Each of the object-side surfaces and the image-side surfaces of the lens elements in the first and other embodiments of the present disclosure may also have one or more critical points in an off-axis region thereof.

[0040] According to the present disclosure, the imaging lens system may include at least one reflective element with a light path deflection function, arranged between an imaged object and the image surface, such as a prism, a reflective mirror, etc. Furthermore, the at least one reflective element may be arranged between an imaged object and the first lens group. The reflective element may have at least one reflective surface.The optical path can be deflected at least once by the at least one reflective surface of the at least one reflective element, which is advantageous for reducing the overall size, so that the imaging lens system can have a deflected optical path and can be more flexible in spatial arrangement, and therefore the dimensions of an electronic device are not limited by the total path length of the imaging lens system, thereby reducing mechanical constraints, miniaturizing the imaging lens system, and thus meeting various specification requirements.

[0041] An angle between the optical axis and the normal direction of the at least one reflective surface of the at least one reflective element is not limited to 45 degrees, but may also have other angles depending on the spatial arrangement. The optical path along an optical axis on the object side can be deflected by the at least one reflective element onto an optical axis on the image side. An angle between a vector of the optical axis on the object side and that on the image side can be any angle, but is not limited to 0, 90, or 180 degrees. In addition, in order to reduce the size of the imaging lens system, the length and width of the reflective mirror may differ from each other, and the length, width, and height of the prism may differ from each other. The surface of the at least one reflective element (e.g.The surface of the prism or the reflecting mirror may be planar, spherical, aspherical, or a freeform shape according to the optical design requirements, but the present disclosure is not limited thereto. The at least one reflective element may consist of more than one prism depending on the design requirements. The prism may be made of glass material or plastic material depending on the design requirements. Furthermore, the prism with the optical path deflection function is not one of the lens elements, that is, the prism with the optical path deflection function is not included in the six lens elements of the imaging lens system.

[0042] Furthermore, Fig. 18 to Fig. 20, each showing a schematic view of a configuration of a reflective element in an imaging lens system according to an embodiment of the present disclosure. As in Fig. 18 to Fig. As shown in Figure 20, the imaging lens system may include, in order from an imaged object (not shown in the drawings) to an image surface IMG along a propagation direction of a light path, a reflective element LF, a lens group LG, a filter FT, and the image surface IMG. Furthermore, the lens group LG may be identical to the two lens groups disclosed in the present disclosure.

[0043] In Fig.18, the reflecting element LF is a prism and has, in series along a propagation direction of the light on the optical path, a first light-transmitting surface LP1, a reflecting surface RF1, and a second light-transmitting surface LP2. The optical path enters the reflecting element LF through the first light-transmitting surface LP1 and reaches the reflecting surface RF1 along a first optical axis OA1. The reflecting surface RF1 deflects the optical path from the first optical axis OA1 to a second optical axis OA2, and the optical path then passes the second light-transmitting surface LP2, passes through the lens group LG and the filter FT, and finally reaches the image surface IMG along the second optical axis OA2. As shown in Fig. 18, both the first light-transmitting surface LP1 and the second light-transmitting surface LP2 of the reflective element LF may be planar.

[0044] In Fig. 19, the reflective element LF is a flat reflecting mirror with a reflecting surface RF1. The beam path reaches the reflecting surface RF1 along a first optical axis OA1. The reflecting surface RF1 deflects the beam path from the first optical axis OA1 to a second optical axis OA2. The beam path then passes through the lens group LG and the filter FT and finally reaches the image surface IMG along the second optical axis OA2.

[0045] In Fig.20, the reflecting element LF is a prism and has, in series along a propagation direction of the light on the optical path, a first light-transmitting surface LP1, a reflecting surface RF1, and a second light-transmitting surface LP2. The light path enters the reflecting element LF through the first light-transmitting surface LP1 and reaches the reflecting surface RF1 along a first optical axis OA1. The reflecting surface RF1 deflects the light path from the first optical axis OA1 to a second optical axis OA2, and the light path then passes the second light-transmitting surface LP2, passes through the lens group LG and the filter FT, and finally reaches the image surface IMG along the second optical axis OA2. As shown in Fig.20, both the first light-transmitting surface LP1 and the second light-transmitting surface LP2 of the reflective element LF may be curved.

[0046] See also Fig. 21 and Fig. 22, each showing a schematic view of a configuration of two reflective elements in an imaging lens system according to an embodiment of the present disclosure. As in Fig. 21 and Fig.As shown in Figure 22, the imaging lens system may include, in order from an imaged object (not shown in the figures) to an image surface IMG along a moving direction of a light path, a first reflective element LF1, a lens group LG, a filter FT, a second reflective element LF2, and the image surface IMG. The light path enters the first reflective element LF1 and reaches the first reflective surface RF1 along a first optical axis OA1, and the first reflective surface RF1 deflects the light path from the first optical axis OA1 to a second optical axis OA2. The light path passes through the lens group LG and the filter FT along the second optical axis OA2.The beam then enters the second reflective element LF2 and reaches the second reflective surface RF2 along the second optical axis OA2. The second reflective surface RF2 deflects the beam from the second optical axis OA2 to a third optical axis OA3. The beam finally reaches the image surface IMG along the third optical axis OA3. Fig. 21, each of the first reflecting elements LF1 and the second reflecting elements LF2 may be a prism. In Fig. 22, the first reflecting element LF1 and the second reflecting element LF2 may be a prism and a flat reflecting mirror, respectively.

[0047] According to the present disclosure, the first lens group cannot exhibit any relative movement with respect to the at least one reflective surface during the zooming or focusing process. Therefore, it is advantageous to prevent expansion or contraction of the overall lens structure of the imaging lens system toward or away from the object side due to the zooming or focusing process, thereby improving the operability and robustness of the lens and simplifying its optical design and mechanism.

[0048] According to the present disclosure, the image surface can move along a direction parallel to the optical axis during the zooming or focusing process. Therefore, focus adjustment for each of the zooms in photography and close focusing can be achieved by moving the image surface along the optical axis, thereby increasing the light convergence quality in various photography scenarios.

[0049] When a focal length of the imaging lens system in the first state with a long focal point end is fLf and a focal length of the imaging lens system in the first state with a short focal point end is fSf, the following condition can be satisfied: 1.20 < fLf / fSf < 2.00. Therefore, this is beneficial for increasing the optical zoom ratio, thereby improving the photography quality in medium to long range photography. In addition, the following condition can also be satisfied: 1.10 < fLf / fSf < 1.70. In addition, the following condition can also be satisfied: 1.20 < fLf / fSf < 1.70. In addition, the following condition can also be satisfied: 1.10 < fLf / fSf < 1.40. In addition, the following condition can also be satisfied: 1.20 < fLf / fSf < 1.40. In addition, the following condition can also be met: 1.33 ≤ fLf / fSf ≤ 1.34.

[0050] When a focal length of the first lens group is fG1 and a focal length of the second lens group is fG2, the following condition can be satisfied: -0.80 < fG1 / fG2 < -0.20. Therefore, it is advantageous to adjust the refractive power distributions of the first lens group and the second lens group so that light can be converged, thereby controlling the viewing angle of the photograph while increasing the amount of incident light. In addition, the following condition can also be satisfied: -0.70 < fG1 / fG2 < -0.30. In addition, the following condition can also be satisfied: -0.60 < fG1 / fG2 < -0.40. In addition, the following condition can also be satisfied: -0.51 ≤ fG1 / fG2 ≤ -0.47.

[0051] When the radius of curvature of the image-side surface of the third lens element is R6 and the radius of curvature of the object-side surface of the fourth lens element is R7, the following condition can be satisfied: -2.00 < R6 / R7 < -0.65. Therefore, it is advantageous to control the light distribution state and the light convergence ability between the image-side surface of the third lens element and the object-side surface of the fourth lens element, thereby controlling the light emission angle on the image-side surface of the third lens element and the light incidence angle on the object-side surface of the fourth lens element, and reducing the sensitivity of the imaging lens system. In addition, the following condition can also be satisfied: -1.60 < R6 / R7 < -0.65. In addition, the following condition can also be satisfied: -1.30 < R6 / R7 < -0.70. In addition, the following condition can also be met: -1.22 ≤ R6 / R7 ≤ -0.76.

[0052] When the maximum field of view of the imaging lens system in the first state with a short focal point end is HFOVSf, the following condition can be satisfied: 3.00 degrees < HFOVSf < 35.00 degrees. Therefore, it is advantageous to have a suitable field of view of the imaging lens system for cooperation with medium-to-long-range photography applications. In addition, the following condition can also be satisfied: 4.00 degrees < HFOVSf < 33.00 degrees. In addition, the following condition can also be satisfied: 5.00 degrees < HFOVSf < 25.00 degrees. In addition, the following condition can also be satisfied: 14.67 degrees ≤ HFOVSf ≤ 17.09 degrees.

[0053] When the radius of curvature of the image-side surface of the lens element of the first lens group of the imaging lens system closest to the image side is RG1i, and the radius of curvature of the object-side surface of the lens element of the second lens group of the imaging lens system closest to the object side is RG2o, the following condition can be satisfied: -2.00 < RG1i / RG2o < -0.65. Therefore, it is advantageous to control the light distribution state and the light convergence ability between the most image-side lens surface of the first lens group and the most object-side lens surface of the second lens group, thereby controlling the light emission angle at the most image-side lens surface and the light incidence angle at the most object-side lens surface, and reducing the sensitivity of the imaging lens system.In addition, the following condition may also be met: -1.60 < RG1 i / RG2o < -0.65. Furthermore, the following condition may also be met: -1.30 < RG1 i / RG2o < -0.70. Furthermore, the following condition may also be met: -1.22 ≤ RG1i / RG2o ≤ -0.76.

[0054] When half of the maximum field of view of the imaging lens system in the first state with a short focal point end is HFOVSf and half of the maximum field of view of the imaging lens system in the first state with a long focal point end is HFOVLf, the following condition can be satisfied: 1.20 < HFOVSf / HFOVLf < 2.50. Therefore, this is beneficial for increasing the optical zoom ratio, thereby improving photography quality and diversity in medium-to-long-range photography. In addition, the following condition can also be satisfied: 1.25 < HFOVSf / HFOVLf < 1.80.

[0055] In addition, the following condition may also be met: 1.30 < HFOVSf / HFOVLf < 1.50.

[0056] When an axial distance between the object-side surface of a lens element closest to the object side and the image-side surface of a lens element closest to the image side of the imaging lens system in the first short-focus-end state is TDSf, an axial distance between the object-side surface of the lens element closest to the object side and the image-side surface of the lens element closest to the image side of the imaging lens system in the first long-focus-end state is TDLf, and an axial distance between the object-side surface of the lens element closest to the object side and the image surface of the imaging lens system in the first short-focus-end state is TLSf, the following condition can be satisfied: 0.20 < (TDSf-TDLf) / TLSf < 0.70.Therefore, it is advantageous to maintain an appropriate balance between the movement amount and the total optical path length of the lens group while covering the optical zoom of the imaging lens system for medium-to-long-range photography. Furthermore, the following condition may also be satisfied: 0.25 < (TDSf-TDLf) / TLSf < 0.60. Furthermore, the following condition may also be satisfied: 0.30 < (TDSf-TDLf) / TLSf < 0.50. In one aspect of the present disclosure, the lens element of the imaging lens system closest to the object side may be the first lens element, and the lens element of the imaging lens system closest to the image side may be the sixth lens element.

[0057] When the axial distance between the object-side surface of the lens element closest to the object side and the image surface of the imaging lens system in the first state with a short focal point end is TLSf, and the axial distance between the object-side surface of the lens element closest to the object side and the image surface of the imaging lens system in the first state with a long focal point end is TLLf, the following condition can be satisfied: 0.00 ≤ 10×|TLSf-TLLf| / TLSf < 1.00. Therefore, it is advantageous to maintain a certain total optical path length during the zooming and focusing processes, thereby simplifying the mechanism design, simplifying the lens assembly, and increasing the yield. In addition, the following condition can also be satisfied: 0.01 < 10×|TLSf-TLLf| / TLSf < 0.50. In addition, the following condition can also be met: 0.05 < 10×|TLSf-TLLf| / TLSf < 0.20.

[0058] When the f-number of the imaging lens system is FnoSf in the first state with a short focal point end, the following condition can be satisfied: 1.50 < FnoSf < 4.00. Therefore, it is advantageous to adjust the f-number of the short focal point end to achieve a reasonable balance between illuminance and depth of field, and to increase the amount of incident light to improve image quality. Furthermore, the following condition can also be satisfied: 1.80 < FnoSf < 3.50. Furthermore, the following condition can also be satisfied: 2.00 < FnoSf < 3.00.

[0059] When the f-number of the imaging lens system is FnoLf in the first state with a long focal point end, the following condition can be satisfied: 1.80 < FnoLf < 4.50. Therefore, it is advantageous to adjust the f-number of the long focal point end to achieve a reasonable balance between illuminance and depth of field, and to increase the amount of incident light to improve image quality. Furthermore, the following condition can also be satisfied: 2.00 < FnoLf < 4.20. Furthermore, the following condition can also be satisfied: 2.50 < FnoLf < 3.80.

[0060] When the focal length of the second lens element is f2 and the focal length of the fifth lens element is f5, the following condition can be satisfied: 0.00 < f2 / f5 < 5.00. Therefore, it is advantageous to balance the light distribution conditions on the object sides and the image sides of both the second and fifth lens elements, thereby reducing their sensitivity. Furthermore, the following condition can also be satisfied: 0.00 < f2 / f5 < 4.50.

[0061] When the axial distance between the object-side surface of the lens element closest to the object side and the image surface of the imaging lens system in the first short-focus state is TLSf, and the maximum image height of the imaging lens system (which may be half the diagonal of an effective photosensitive area of ​​an image sensor) is ImgH, the following condition can be satisfied: 3.50 < TLSf / ImgH < 7.50. Therefore, it is advantageous to balance the image height and the total path length of the imaging lens system at the short focal end to enhance the experience of portrait photography and thereby highlight the imaged character. In addition, the following condition can also be satisfied: 4.00 <TLSf / ImgH<7,00.

[0062] When the axial distance between the object-side surface of the lens element closest to the object side and the image surface of the imaging lens system in the first long-focal-end state is TLLf, and the maximum image height of the imaging lens system is ImgH, 3.50 < TLLf / ImgH < 7.50. Therefore, it is advantageous to balance the image height and the total path length of the imaging lens system at the long focal end to provide a short depth of field, thereby blurring the distant background and adjusting characteristics such as distance detection in a scene. In addition, the following condition can also be satisfied: 4.00 < TLLf / ImgH < 7.00.

[0063] When an axial distance between the object-side surface of a lens element of the first lens group closest to the object side and the image-side surface of the lens element of the first lens group closest to the image side is TG1, and an axial distance between the object-side surface of the lens element of the second lens group closest to the object side and the image-side surface of a lens element of the second lens group closest to the image side is TG2, the following condition can be satisfied: 0.50 < TG1 / TG2 < 4.50. Therefore, it is advantageous to adjust the length of the first lens group along the optical axis and the length of the second lens group along the optical axis so that the spatial configuration of the lens elements is balanced, thereby reducing the sensitivity of the optical lens system during the zooming operation or the focusing process.In addition, the following condition may also be satisfied: 1.00 < TG1 / TG2 < 3.00. In addition, the following condition may also be satisfied: 1.20 < TG1 / TG2 < 1.80. In one aspect of the present disclosure, the lens element of the first lens group closest to the object side may be the first lens element, the lens element of the first lens group closest to the image side may be the third lens element, the lens element of the second lens group closest to the object side may be the fourth lens element, and the lens element of the second lens group closest to the image side may be the sixth lens element.

[0064] When the f-number of the imaging lens system in the first state with a short focal point end is FnoSf and the f-number of the imaging lens system in the second state with a short focal point end is FnoSn, the following condition can be satisfied: 0.01 < 10×|FnoSn-FnoSf| < 1.00. Therefore, this is beneficial for achieving a proper balance between the incident light amounts of a distance shot and a close-up shot at both the short focal point end and the long focal point end during the focusing process. In addition, the following condition can also be satisfied: 0.05 < 10×|FnoSn-FnoSf| < 0.80. In addition, the following condition can also be satisfied: 0.05 < 10×|FnoSn-FnoSf| < 0.50.

[0065] When the f-number of the imaging lens system in the first state with a long focal point end is FnoLf and the f-number of the imaging lens system in the second state with a long focal point end is FnoLn, the following condition can be satisfied: 0.01 < 10×|FnoLn-FnoLf| < 1.00. Therefore, this is beneficial for achieving an appropriate balance between the incident light amounts of a long exposure and a short exposure at both the long focal point end and the short focal point end during the focusing process. In addition, the following condition can also be satisfied: 0.10 < 10×|FnoLn-FnoLf| < 0.80. In addition, the following condition can also be satisfied: 0.20 < 10×|FnoLn-FnoLf| < 0.60.

[0066] When the axial distance between the object-side surface of the lens element closest to the object side and the image surface of the imaging lens system in the first short-focus state is TLSf, an axial distance between the object-side surface of the lens element closest to the object side and the image surface of the imaging lens system in the second short-focus state is TLSn, the focal length of the imaging lens system in the first short-focus state is fSf, and a focal length of the imaging lens system in the second short-focus state is fSn, the following condition can be satisfied: 0.10 < 10×(TLSn / fSn-TLSf / fSf) < 0.80. Therefore, it is advantageous to achieve an appropriate balance between the size-to-field ratios of a distance shot and a close-up shot at both the short-focus end and the long-focus end during the focusing process.In addition, the following condition can also be met: 0.15 < 10×(TLSn / fSn-TLSf / fSf) < 0.50. In addition, the following condition can also be met: 0.18 < 10×(TLSn / fSn-TLSf / fSf) < 0.30.

[0067] When the axial distance between the object-side surface of the lens element closest to the object side and the image surface of the imaging lens system in the first long-focus-end state is TLLf, an axial distance between the object-side surface of the lens element closest to the object side and the image surface of the imaging lens system in the second long-focus-end state is TLLn, the focal length of the imaging lens system in the first long-focus-end state is fLf, and a focal length of the imaging lens system in the second long-focus-end state is fLn, the following condition can be satisfied: 0.10 < 10×(TLLn / fLn-TLLf / fLf) < 0.80. Therefore, this is advantageous for achieving an appropriate balance between the size-to-field-of-view ratios of a distance shot and a close-up shot at both the long-focus end and the short-focus end during the focusing process.In addition, the following condition may also be met: 0.15 < 10×(TLLn / fLn-TLLf / fLf) < 0.65. In addition, the following condition may also be met: 0.18<10×(TLLn / fLn−TLLf / fLf)<0.50.

[0068] When the radius of curvature of the image-side surface of the third lens element is R6 and a central thickness of the third lens element is CT3, the following condition can be satisfied: -10.00 < R6 / CT3 < 0.00. Therefore, this is beneficial for controlling the refractive power of the third lens element and balancing the light distribution state on the objective side of the third lens element, thereby increasing the light convergence ability and reducing the sensitivity of the third lens element. Furthermore, the following condition can also be satisfied: -8.00 < R6 / CT3 < -0.50. Furthermore, the following condition can also be satisfied: -6.00 < R6 / CT3 < -1.00.

[0069] When the radius of curvature of the object-side surface of the fourth lens element is R7 and a central thickness of the fourth lens element is CT4, the following condition can be satisfied: 0.00 < R7 / CT4 < 10.00. Therefore, this is beneficial for controlling the refractive power of the fourth lens element and balancing the light distribution state on an image side of the fourth lens element, thereby increasing the light convergence capability and reducing the sensitivity of the fourth lens element. Furthermore, the following condition can also be satisfied: 1.00 < R7 / CT4 < 8.00. Furthermore, the following condition can also be satisfied: 2.00 < R7 / CT4 < 6.00.

[0070] When the image surface shifts during the transition of the imaging lens system from the first short focal point end state to the second short focal point end state, DImgS, the following condition can be satisfied: 0.050 mm (millimeters) < DImgS < 0.800 mm. Therefore, focus adjustment for each of the photography zooms and close focusing can be achieved by moving the image surface along the optical axis, thereby improving the light convergence quality in various photography scenarios. In addition, the following condition can also be satisfied: 0.100 mm < DImgS < 0.600 mm. In addition, the following condition can also be satisfied: 0.150 mm < DImgS < 0.500 mm.

[0071] When the displacement of the image surface during the change of the imaging lens system from the first short-focus state to the second short-focus state is DImgS and is a minimum value among the central thicknesses of all lens elements of the imaging lens system, CTmin, the following condition can be satisfied: 0.10 < DImgS / CTmin < 1.50. Therefore, it is advantageous to maintain the ratio of the amount of movement of the image surface to the central thickness of the thinnest lens element, shift the image sensor while complying with the manufacturing limitation of the lens thickness, and increase the contrast and clarity of images during zoom photography or close focusing. In addition, the following condition can also be satisfied: 0.15 < DImgS / CTmin < 1.00. In addition, the following condition can also be satisfied: 0.20 < DImgS / CTmin < 0.80.

[0072] According to the present disclosure, the above features and conditions can be used in numerous combinations to achieve corresponding effects.

[0073] According to the present disclosure, the lens elements of the imaging lens system can be made of either glass or plastic material. When the lens elements are made of glass material, the refractive power distribution of the imaging lens system can be more flexible, and the influence on imaging caused by a change in ambient temperature can be reduced. The glass lens element can be manufactured either by grinding or molding. When the lens elements are made of plastic material, the manufacturing cost can be effectively reduced. Furthermore, surfaces of each of the lens elements can be arranged to be spherical or aspherical. Spherical lens elements are easy to manufacture.The design of aspherical lens elements allows for more control variables to eliminate aberrations and reduce the required number of lens elements, effectively shortening the overall path length of the imaging lens system. Additionally, the aspherical surfaces can be formed by plastic injection molding or glass molding.

[0074] According to the present disclosure, when a lens surface is aspherical, it means that the lens surface has an aspherical shape in its entire optically effective area or one or more portions thereof.

[0075] According to the present disclosure, the material of one or more lens elements may optionally include an additive that creates light absorption and interference effects and modifies the transmittance of the lens elements in a specific wavelength range to reduce unwanted stray light or color variations. For example, the additive may optionally filter out light in the wavelength range of 600 nm to 800 nm to reduce excessive red light and / or near-infrared light, or optionally filter out light in the wavelength range of 350 nm to 450 nm to prevent excessive blue light and / or near-ultraviolet light from interfering with the final image. The additive may be homogeneously blended with a plastic material used to manufacture a blended-material lens element by injection molding. Furthermore, the additive may be applied to the lens surfaces to achieve the aforementioned effects.

[0076] According to the present disclosure, each of the object-side surfaces and the image-side surfaces has a paraxial region and an off-axis region. The paraxial region refers to the region of the surface where light rays travel close to the optical axis, and the off-axis region refers to the region of the surface far from the paraxial region. Specifically, unless otherwise specified, when the lens element has a convex surface, it means that the surface is convex in the paraxial region thereof; when the lens element has a concave surface, it means that the surface is concave in the paraxial region thereof. When a portion of the refractive power or focal point of a lens element is undefined, it means that the portion of the refractive power or focal point of the lens element lies in its paraxial region.

[0077] According to the present disclosure, an inflection point is a point on the surface of the lens element where the surface changes from concave to convex, or vice versa. A critical point is an off-axial point on the lens surface where its tangent is perpendicular to the optical axis.

[0078] According to the present disclosure, the image surface of the imaging lens system may be flat or curved based on the corresponding image sensor, wherein in particular a curved surface is concavely facing the object side of the imaging lens system.

[0079] According to the present disclosure, an image correction unit, such as a field flattener, can optionally be arranged between the lens element located along the optical path closest to the image side of the imaging lens system and the image surface to correct aberrations such as field curvature. The optical properties of the image correction unit, such as curvature, thickness, refractive index, position, and surface shape (convex or concave surface with spherical, aspherical, diffractive, or Fresnel types), can be adjusted according to the design of the image acquisition unit. In general, a preferred image correction unit is, for example, a thin transparent element having a concave object-side surface and a planar image-side surface, and the thin transparent element is arranged near the image surface.

[0080] According to the present disclosure, the imaging lens system may include at least one diaphragm, such as an aperture diaphragm, a glare diaphragm, or a field diaphragm. The glare diaphragm or the field diaphragm may be disposed between an imaged object and the first lens element, between adjacent lens elements, or between the last lens element and the image surface, and is configured to eliminate stray light and thereby improve the image quality thereof.

[0081] According to the present disclosure, an aperture stop can be configured as a front stop or a center stop. A front stop disposed between an imaged object and the first lens element can provide a greater distance between an exit pupil of the imaging lens system and the image surface to create a telecentric effect, thereby improving the image sensor efficiency of an image sensor (e.g., CCD or CMOS). A center stop disposed between the first lens element and the image surface is advantageous for increasing the viewing angle of the imaging lens system, thereby providing a wider field of view for the same.

[0082] According to the present disclosure, the imaging lens system may include an aperture control unit. The aperture control unit may be a mechanical component or a light modulator that can control the size and shape of the aperture through electricity or electrical signals. The mechanical component may include a movable element, such as a diaphragm assembly or a light-shielding film. The light modulator may include a shielding element, such as a filter, an electrochromic material, or a liquid crystal layer. The aperture control unit controls the amount of incident light or the exposure time to enhance the ability to adjust image quality. Furthermore, the aperture control unit may be the aperture stop of the present disclosure, which changes the f-number to achieve various imaging effects, such as depth of field or lens sensitivity.

[0083] According to the present disclosure, the imaging lens system may include one or more optical elements for limiting the shape of the light passing through the imaging lens system. Each of the optical elements may be, for example, a filter, a polarizer, etc., and each of the optical elements may be, for example, a single-piece element, a composite component, a thin film, etc. The optical element may be disposed on the object side or the image side of the imaging lens system, or between any two adjacent lens elements, to transmit light in a specific shape and thereby meet application requirements.

[0084] According to the present disclosure, the imaging lens system may include at least one optical lens element, an optical element, or a substrate having at least one surface with a low-reflection layer. The low-reflection layer can effectively reduce stray light resulting from light reflection at the interface. The reflection-reducing layer may be disposed in an optically ineffective region of an object-side surface or an image-side surface of the optical lens element, or a connecting surface between the object-side surface and the image-side surface. The optical element may be a light-blocking element, an annular spacer element, a tube element, a cover glass, a blue glass, a filter, a color filter, a light-path deflecting element, a prism, a mirror, etc.The carrier may be a base for holding a lens assembly, a microlens disposed on an image sensor, a substrate surrounding the image sensor, a glass plate for protecting the image sensor, etc.

[0085] According to the present disclosure, the imaging lens system may further include a light-blocking element. The light-blocking element may have a non-circular opening, and the non-circular opening may have different effective radii in different directions perpendicular to the optical axis. Therefore, it is advantageous to coordinate with the shape of non-circular lens elements or aperture stops to effectively save space and fully utilize the light passing through the non-circular lens elements or aperture stops, thereby reducing stray light. Furthermore, the light-blocking element may be provided with a wave-like structure or a serrated structure on a periphery of an inner hole portion thereof.

[0086] According to the present disclosure, the object side and the image side are defined according to the direction of the optical axis, and the axial optical data is calculated along the optical axis. Furthermore, when the optical axis is deflected by a light deflecting element, the axial optical data is also calculated along the deflected optical axis.

[0087] In accordance with the above description of the present disclosure, the following specific embodiments are provided for further explanation. 1. Embodiment

[0088] Fig. 1 is a schematic view of an image acquisition unit in each of a first short focal end state and a first long focal end state according to the first embodiment of the present disclosure. Fig.2 shows, in order from left to right, spherical aberration curves, astigmatic field curves, and a distortion curve of the image pickup unit in the first state with a short focal point end according to the first embodiment. Fig. Figure 3 shows, in order from left to right, spherical aberration curves, astigmatic field curves, and a distortion curve of the image pickup unit in the first state with a long focal point end according to the first embodiment. The upper part of Fig. 1 shows the imaging lens system in the first state with short focal point end, and the lower part of Fig. 1 shows the imaging lens system in the first state with a long focal point end. In Fig.1, the image acquisition unit 1 includes the imaging lens system (the reference numeral of which is omitted) of the present disclosure and an image sensor IS. The imaging lens system includes, in order from an object side to an image side along a light path, a reflective element LF, a stop S1, a first lens element E1, an aperture stop ST, a second lens element E2, a third lens element E3, a stop S2, a stop S3, a fourth lens element E4, a fifth lens element E5, a sixth lens element E6, a filter E7, and an image surface IMG. Further, the imaging lens system includes, in order from the object side to the image side along the light path, a first lens group G1 and a second lens group G2.The first lens group G1 includes the first lens element E1, the second lens element E2, and the third lens element E3, and the second lens group G2 includes the fourth lens element E4, the fifth lens element E5, and the sixth lens element E6. The imaging lens system includes six lens elements (E1, E2, E3, E4, E5, and E6) with no additional lens element disposed between each of the adjacent six lens elements.

[0089] The imaging lens system has a first state corresponding to an infinite object distance and a second state corresponding to a finite object distance. The first state refers to a state of the imaging lens system with an imaged object at an infinite distance (the infinite object distance), and the second state refers to a state of the imaging lens system with an imaged object at a finite distance (the finite object distance). When an imaged object at the infinite object distance moves to the finite object distance, the imaging lens system performs a focusing process to change the first state to the second state thereof. Conversely, when an imaged object at the finite object distance moves to the infinite object distance, the imaging lens system also performs the focusing process to change the second state to the first state thereof.

[0090] Furthermore, during the focusing process of the imaging lens system, the first lens group G1 has no relative movement with respect to a reflective surface of the reflective element LF, the second lens group G2 moves along a direction parallel to an optical axis with respect to the first lens group G1, and the image surface IMG moves along a direction parallel to the optical axis. Note that during the zooming operation, no relative movement occurs between any two lens elements of each of the first lens group and the second lens group of the two lens groups.

[0091] The imaging lens system in the first state has a first long focal point state corresponding to a long focal point end and a first short focal point state corresponding to a short focal point end during a zooming operation. When the imaging lens system changes its first long focal point state to the first short focal point state during the zooming operation, the second lens group G2 moves along a direction parallel to the optical axis toward the image side with respect to the first lens group G1. Conversely, when the imaging lens system changes its first short focal point state to the first long focal point state during the zooming operation, the second lens group G2 moves along a direction parallel to the optical axis toward the object side with respect to the first lens group G1. As shown in Fig. 1, the upper part of Fig.1 the imaging lens system in the first state with short focal point end, and the lower part of Fig.Figure 1 shows the imaging lens system in the first state with a long focal point end. Similarly, the imaging lens system in the second state has a second long focal point end state corresponding to the long focal point end and a second short focal point end state corresponding to the short focal point end during the zooming operation. Furthermore, during the zooming operation of the imaging lens system, the first lens group G1 has no relative movement with respect to the reflective surface of the reflective element LF, the second lens group G2 moves along a direction parallel to the optical axis with respect to the first lens group G1, and the image surface IMG moves along a direction parallel to the optical axis. Note that during the zooming operation, there is no relative movement between any two lens elements of each of the first lens group and the second lens group of the two lens groups.

[0092] The first lens element E1 with negative refractive power has an object-side surface that is concave in a paraxial region thereof and an image-side surface that is concave in a paraxial region thereof. The first lens element E1 is made of plastic material and has both the object-side surface and the image-side surface aspherical. The image-side surface of the first lens element E1 has an inflection point in an off-axis region thereof. The image-side surface of the first lens element E1 has a critical point in its off-axis region.

[0093] The second lens element E2 with negative refractive power has an object-side surface that is convex in a paraxial region thereof and an image-side surface that is concave in a paraxial region thereof. The second lens element E2 is made of plastic material and has the object-side surface and the image-side surface both aspherical. The object-side surface of the second lens element E2 has an inflection point in an off-axis region thereof. The image-side surface of the second lens element E2 has an inflection point in an off-axis region thereof. The object-side surface of the second lens element E2 has a critical point in the off-axis region thereof. The image-side surface of the second lens element E2 has a critical point in the off-axis region thereof.

[0094] The third lens element E3 with positive refractive power has an object-side surface that is convex in a paraxial region thereof and an image-side surface that is convex in a paraxial region thereof. The third lens element E3 is made of glass material and has both the object-side surface and the image-side surface aspherical. The object-side surface of the third lens element E3 has an inflection point in an off-axis region thereof. The object-side surface of the third lens element E3 has a critical point in the off-axis region thereof.

[0095] The fourth lens element E4 with positive refractive power has an object-side surface that is convex in a paraxial region thereof and an image-side surface that is concave in a paraxial region thereof. The fourth lens element E4 is made of plastic material and has both an object-side surface and an image-side surface that are aspherical. The image-side surface of the fourth lens element E4 has two inflection points in an off-axis region thereof. The image-side surface of the fourth lens element E4 has two critical points in its off-axis region.

[0096] The fifth lens element E5 with negative refractive power has an object-side surface that is concave in a paraxial region thereof and an image-side surface that is concave in a paraxial region thereof. The fifth lens element E5 is made of plastic material and has the object-side surface and the image-side surface both aspherical. The object-side surface of the fifth lens element E5 has an inflection point in an off-axis region thereof. The image-side surface of the fifth lens element E5 has two inflection points in an off-axis region. The object-side surface of the fifth lens element E5 has a critical point in the off-axis region. The image-side surface of the fifth lens element E5 has a critical point in the off-axis region.

[0097] The sixth lens element E6 with negative refractive power has an object-side surface that is convex in a paraxial region thereof and an image-side surface that is concave in a paraxial region thereof. The sixth lens element E6 is made of plastic material and has both the object-side surface and the image-side surface aspherical. The object-side surface of the sixth lens element E6 has two inflection points in an off-axis region thereof. The image-side surface of the sixth lens element E6 has two inflection points in an off-axis region thereof. The object-side surface of the sixth lens element E6 has a critical point in the off-axis region thereof.

[0098] The reflective element LF is made of glass material. The reflective element LF is arranged between an imaged object and the first lens group G1 (it can also be assumed that the reflective element LF is arranged on an object side of the first lens element E1). The reflective element LF has no influence on the focal length of the imaging lens system. The reflective element LF is a prism that provides a light path deflection function. For the sake of simplicity, the light path deflected by the reflective element LF is Fig.1 is omitted. The reflective element LF has an object-side surface and an image-side surface, both of which are planar, but the present disclosure is not limited thereto. The reflective element LF may have various shapes to achieve different deflection effects on the ray path. For example, the reflective element LF of the first embodiment may be the reflective element LF shown in Fig. 18 to Fig. 20, which deflects the beam path once, whereby the reflecting surface RF1 of the reflecting element LF deflects the first axis OA1 into the second optical axis OA2. The details can be found in the description. Fig. 18 to Fig. 20, which are not repeated here.

[0099] The filter E7 is made of glass and is located between the sixth lens element E6 and the image surface IMG. It does not affect the focal length of the imaging lens system. The image sensor IS is located on or near the image surface IMG.

[0100] The equation of the aspherical surface profiles of the aforementioned lens elements of the first embodiment is expressed as follows: X(Y)=(Y2 / R) / (1+sqrt(1−(1+k)×(Y / R)2))+∑i(Ai)×(Yi) , where X is the displacement parallel to the optical axis from an axial vertex on the aspherical surface to a point at a distance Y from the optical axis on the aspherical surface; Y is the vertical distance from the point on the aspherical surface to the optical axis; R is the radius of curvature; k is the conicity coefficient; and Ai is the i-th aspherical coefficient, where in the embodiments i can be, but is not limited to, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26 and 28.

[0101] In the imaging lens system of the image sensing unit 1 according to the first embodiment, a lens element having the maximum central thickness of the imaging lens system is the fourth lens element E4.

[0102] In the imaging lens system of the image sensing unit 1 according to the first embodiment, the first lens element E1 is a lens element of the imaging lens system closest to the object side and a lens element of the first lens group G1 closest to the object side, the third lens element E3 is a lens element of the first lens group G1 closest to the image side, the fourth lens element E4 is a lens element of the second lens group G2 closest to the object side, and the sixth lens element E6 is a lens element of the imaging lens system closest to the image side and a lens element of the second lens group G2 closest to the image side.

[0103] When a focal length of the imaging lens system in the first state with a short focal point end is fSf, an F-number of the imaging lens system in the first state with a short focal point end is FnoSf, half of a maximum field of view of the imaging lens system in the first state with a short focal point end is HFOVSf, an axial distance between the object-side surface of the lens element closest to the object side and the image surface of the imaging lens system in the first state with a short focal point end is TLSf, and an axial distance between the object-side surface of the lens element closest to the object side and the image-side surface of the lens element closest to the image side of the imaging lens system in the first state with a short focal point end is TDSf, the following conditions are satisfied: fSf = 12.99 mm (millimeters); FnoSf = 2.40; HFOVSf = 16.2 degrees; TLSf = 22.308 mm; and TDSf = 19.549 mm.In this embodiment, TLSf is an axial distance between the object-side surface of the first lens element E1 and the image surface IMG in the imaging lens system in the first short focal point end state, and TDSf is an axial distance between the object-side surface of the first lens element E1 and the image-side surface of the sixth lens element E6 in the imaging lens system in the first short focal point end state.

[0104] When a focal length of the imaging lens system in the first state with a long focal point end is fLf, an F-number of the imaging lens system in the first state with a long focal point end is FnoLf, half of a maximum field of view of the imaging lens system in the first state with a long focal point end is HFOVLf, an axial distance between the object-side surface of the lens element closest to the object side and the image surface of the imaging lens system in the first state with a long focal point end is TLLf, and an axial distance between the object-side surface of the lens element closest to the object side and the image-side surface of the lens element closest to the image side of the imaging lens system in the first state with a long focal point end is TDLf, the following conditions are satisfied: fLf = 17.32 mm; FnoLf = 3.20; HFOVLf = 11.7 degrees; TLLf = 22.509 mm; and TDLf = 10.622 mm.In this embodiment, TLLf is an axial distance between the object-side surface of the first lens element E1 and the image surface IMG in the imaging lens system in the first long focal point end state, and TDLf is an axial distance between the object-side surface of the first lens element E1 and the image-side surface of the sixth lens element E6 in the imaging lens system in the first long focal point end state.

[0105] When a focal length of the imaging lens system in the second short-focus state is fSn, an F-number of the imaging lens system in the second short-focus state is FnoSn, half of a maximum field of view of the imaging lens system in the second short-focus state is HFOVSn, an axial distance between the object-side surface of the lens element closest to the object side and the image surface of the imaging lens system in the second short-focus state is TLSn, and an axial distance between the object-side surface of the lens element closest to the object side and the image-side surface of the lens element closest to the image side of the imaging lens system in the second short-focus state is TDSn, the following conditions are satisfied: fSn = 12.91 mm; FnoSn = 2.41; HFOVSn = 16.1 degrees; TLSn = 22.473 mm; and TDSn = 19.780 mm.In this embodiment, TLSn is an axial distance between the object-side surface of the first lens element E1 and the image surface IMG in the imaging lens system in the second short focal point end state, and TDSn is an axial distance between the object-side surface of the first lens element E1 and the image-side surface of the sixth lens element E6 in the imaging lens system in the second short focal point end state.

[0106] When a focal length of the imaging lens system in the second long-focus state is fLn, an F-number of the imaging lens system in the second long-focus state is FnoLn, half of a maximum field of view of the imaging lens system in the second long-focus state is HFOVLn, an axial distance between the object-side surface of the lens element closest to the object side and the image surface of the imaging lens system in the second long-focus state is TLLn, and an axial distance between the object-side surface of the lens element closest to the object side and the image-side surface of the lens element closest to the image side of the imaging lens system in the first long-focus state is TDLn, the following conditions are satisfied: fLn = 16.96 mm; FnoLn = 3.17; HFOVLn = 11.8 degrees; TLLn = 22.511 mm; and TDLn = 11.189 mm.In this embodiment, TLLn is an axial distance between the object-side surface of the first lens element E1 and the image surface IMG in the imaging lens system in the second long-focus-end state, and TDLn is an axial distance between the object-side surface of the first lens element E1 and the image-side surface of the sixth lens element E6 in the imaging lens system in the second long-focus-end state.

[0107] In this embodiment, D0 is an axial distance between an imaged object and the object-side surface of the reflective element LF (which is approximate to an object distance of the imaging lens system), D1 is an axial distance between the diaphragm S2 and the diaphragm S3, D2 is an axial distance between the image-side surface of the sixth lens element E6 and the filter E7, and D3 is a moving distance of the image surface IMG along the optical axis (the comparison origin of which is based on the imaging lens system in the first short-focus state). The imaging lens system is changeable between the first short-focus state, the first long-focus state, the second short-focus state, and the second long-focus state through the zooming process or the focusing process, and the values ​​of D0 to D3 vary accordingly.When the imaging lens system is in the first state with a short focal point end, the above parameters have the following values: object distance = ∞ (infinity); D0 = ∞; D1 = 11.185 mm; D2 = 2.051 mm; and D3 = 0.000 mm. When the imaging lens system is in the first state with a long focal point end, the above parameters have the following values: object distance = ∞; D0 = ∞; D1 = 2.258 mm; D2 = 11.158 mm; and D3 = 0.021 mm. When the imaging lens system is in the second state with a short focal point end, the above parameters have the following values: objective distance = 1508.195 mm; D0 = 1500.000 mm; D1 = 11.416 mm; D2 = 1.820 mm; and D3 = 0.165 mm. When the imaging lens system is in the second long focal point state, the above parameters have the following values: object distance = 1508.195 mm; D0 = 1500.000 mm; D1 = 2.825 mm; D2 = 10.412 mm; and D3 = 0.202 mm.

[0108] If half of the maximum field of view of the imaging lens system in the first state with short focal point end is HFOVSf and half of the maximum field of view of the imaging lens system in the first state with long focal point end is HFOVLf, the following condition is satisfied: HFOVSf / HFOVLf = 1.38.

[0109] When the axial distance between the object-side surface of the lens element closest to the object side (the first lens element E1) and the image surface IMG of the imaging lens system in the first state with a short focal point end is TLSf, and the axial distance between the object-side surface of the lens element closest to the object side (the first lens element E1) and the image surface IMG of the imaging lens system in the first state with a long focal point end is TLLf, the following condition is satisfied: 10×|TLSf-TLLf| / TLSf = 0.09.

[0110] When the axial distance between the object-side surface of the lens element closest to the object side (the first lens element E1) and the image-side surface of the lens element closest to the image side (the sixth lens element E6) of the imaging lens system in the first short-focus state is TDSf, the axial distance between the object-side surface of the lens element closest to the object side (the first lens element E1) and the image-side surface of the lens element closest to the image side (the sixth lens element E6) of the imaging lens system in the first long-focus state is TDLf, and the axial distance between the object-side surface of the lens element closest to the object side (the first lens element E1) and the image surface IMG of the imaging lens system in the first short-focus state is TLSf,the following condition is met: (TDSf-TDLf) / TLSf = 0.40.,

[0111] When the axial distance between the object-side surface of the lens element closest to the object side (the first lens element E1) and the image surface IMG of the imaging lens system in the first short focal point end state is TLSf and a maximum image height of the imaging lens system is ImgH, the following condition is satisfied: TLSf / ImgH = 6.20.

[0112] When the axial distance between the object-side surface of the lens element closest to the object side (the first lens element E1) and the image surface IMG of the imaging lens system in the first long focal point end state is TLLf and the maximum image height of the imaging lens system is ImgH, the following condition is satisfied: TLLf / ImgH = 6.25.

[0113] If the focal length of the imaging lens system in the first state with long focal point end is fLf and the focal length of the imaging lens system in the first state with short focal point end is fSf, the following condition is satisfied: fLf / fSf = 1.33.

[0114] If a focal length of the first lens group G1 is fG1 and a focal length of the second lens group G2 is fG2, the following condition is satisfied: fG1 / fG2=−0.47.

[0115] When a radius of curvature of the image-side surface of the third lens element E3 is R6 and a radius of curvature of the object-side surface of the fourth lens element E4 is R7, the following condition is satisfied: R6 / R7 = - 0.89.

[0116] When a radius of curvature of the image-side surface of the lens element of the first lens group G1 of the imaging system closest to the image side (the third lens element E3) is RG1i and a radius of curvature of the object-side surface of the lens element of the second lens group G2 of the imaging system closest to the object side (the fourth lens element E4) is RG2o, the following condition is satisfied: RG1i / RG2o = -0.89.

[0117] When an axial distance between the object-side surface of the lens element of the first lens group G1 closest to the object side (the first lens element E1) and the image-side surface of the lens element of the first lens group G1 closest to the image side (the third lens element E3) is TG1, and an axial distance between the object-side surface of the lens element of the second lens group G2 closest to the object side (the fourth lens element E4) and the image-side surface of the lens element of the second lens group G2 closest to the image side (the sixth lens element E6) is TG2, the following condition is satisfied: TG1 / TG2 = 1.48.

[0118] If the f-number of the imaging lens system in the first state with short focal point end is FnoSf and the f-number of the imaging lens system in the second state with short focal point end is FnoSn, the following condition is satisfied: 10×|FnoSn-FnoSf| = 0.10.

[0119] If the f-number of the imaging lens system in the first long focal point end state is FnoLf and the f-number of the imaging lens system in the second long focal point end state is FnoLn, the following condition is satisfied: 10×|FnoLn-FnoLf| = 0.30.

[0120] When the axial distance between the object-side surface of the lens element closest to the object side (the first lens element E1) and the image surface IMG of the imaging lens system in the first short-focus state is TLSf, the axial distance between the object-side surface of the lens element closest to the object side (the first lens element E1) and the image surface IMG of the imaging lens system in the second short-focus state is TLSn, the focal length of the imaging lens system in the first short-focus state is fSf, and the focal length of the imaging lens system in the second short-focus state is fSn, the following condition is satisfied: 10×(TLSn / fSn-TLSf / fSf) = 0.23.

[0121] When the axial distance between the object-side surface of the lens element closest to the object side (the first lens element E1) and the image surface IMG of the imaging lens system in the first long-focus state is TLLf, the axial distance between the object-side surface of the lens element closest to the object side (the first lens element E1) and the image surface IMG of the imaging lens system in the second long-focus state is TLLn, the focal length of the imaging lens system in the first long-focus state is fLf, and the focal length of the imaging lens system in the second long-focus state is fLn, the following condition is satisfied: 10×(TLLn / fLn-TLLf / fLf) = 0.28.

[0122] When a focal length of the second lens element E2 is f2 and a focal length of the fifth lens element E5 is f5, the following condition is satisfied: f2 / f5 = 4.22.

[0123] When the radius of curvature of the image-side surface of the third lens element E3 is R6 and a central thickness of the third lens element E3 is CT3, the following condition is satisfied: R6 / CT3 = -3.26.

[0124] When the radius of curvature of the object-side surface of the fourth lens element E4 is R7 and a central thickness of the fourth lens element E4 is CT4, the following condition is satisfied: R7 / CT4 = 3.17.

[0125] If a displacement of the image surface IMG during the change of the imaging lens system from the first short focal point end state to the second short focal point end state is DImgS, the following condition is satisfied: DImgS = 0.165 mm.

[0126] When the displacement of the image surface IMG during the transition of the imaging lens system from the first short focal point end state to the second short focal point end state is DImgS and a minimum value among the central thicknesses of all lens elements of the imaging lens system is CTmin, the following condition is satisfied: DImgS / CTmin = 0.27. In this embodiment, among the first lens element E1 to the sixth lens element E6, a central thickness of the fifth lens element E5 or a central thickness of the sixth lens element E6 is smaller than that of each of the other lens elements, so CTmin is the central thickness of the fifth lens element E5 or the central thickness of the sixth lens element E6.

[0127] The detailed optical data of the first embodiment are shown in Table 1A and Table 1B, and the data of the aspherical surface are shown in Table 1C below. TABLE 1A 1. Embodiment Surface # radius of curvature thickness material index Abbé # Focal length 0 lens Plano D0 1 Reflective element Plano 6,850 Glass 1,847 23,80 - 2 Plano 0,845 3 stop Plano 0,500 4 Lens 1 -34,2793 (ASP) 1,163 plastic 1,545 56,1 -29,67 5 30,9702 (ASP) 1,172 6 Ape. Stop Plano 0,564 7 Lens 2 250,0000 (ASP) 1,200 plastic 1,614 26,0 -40,52 8 22,5781 (ASP) 0,240 9 Lens 3 16,9911 (ASP) 1,816 Glass 1,497 81,6 9,08 10 -5,9288 (ASP) -1,009 11 stop Plano D1 12 stop Plano -0,949 13 Lens 4 6,6324 (ASP) 2,092 plastic 1,545 56,1 12,45 14 265,7683 (ASP) 0,430 15 Lens 5 -33,7708 (ASP) 0,600 plastic 1,534 56,0 -9,61 16 6,0958 (ASP) 0,445 17 Lens 6 4,3424 (ASP) 0,600 plastic 1,584 28,2 -32,14 18 3,3470 (ASP) D2 19 filter Plano 0,210 Glass 1,517 64,2 - 20 Plano 0,498 21 Picture Plano D3 Note: The reference wavelength is 587.6 nm (d-line). The effective radius of aperture S1 (surface 3) is 2.765 mm. The effective radius of aperture S2 (surface 11) is 3.525 mm. The effective radius of aperture S3 (surface 12) is 3.120 mm.

[0128] Table 1A lists the radius of curvature, thickness, and focal length in millimeters (mm). The surface count (0-21) represents the surfaces arranged along the optical axis from the object side to the image side. TABLE 1B Optical data for an imaging lens system in the first state with a short focal point end, in the first state with a long focal point end, in the second state with a short focal point end, and in the second state with a long focal point end First state with short focal point end First state with long focal point end fSf [mm] 12,99 fLf [mm] 17,32 FnoSf 2,40 FnoLf 3,20 HFOVSf [deg.] 16,2 HFOVLf [deg.] 11,7 Distance to lens[mm] infinity Distance to lens[mm] infinity D0 [mm] infinity D0 [mm] infinity D1 [mm] 11,185 D1 [mm] 2,258 D2 [mm] 2,051 D2 [mm] 11,158 D3 [mm] 0,000 D3 [mm] 0,021 Second state with short focal point end Second state with long focal point end fSn [mm] 12,91 fLn [mm] 16,96 FnoSn 2,41 FnoLn 3,17 HFOVSn [deg.] 16,1 HFOVLn [deg.] 11,8 Distance to lens[mm] 1508,195 Distance to lens[mm] 1508,195 D0 [mm] 1500,000 D0 [mm] 1500,000 D1 [mm] 11,416 D1 [mm] 2,825 D2 [mm] 1,820 D2 [mm] 10,412 D3 [mm] 0,165 D3 [mm] 0,202

[0129] Table 1B shows optical data of the imaging lens system in the first short focal point end state, the first long focal point end state, the second short focal point end state, and the second long focal point end state under various focal conditions and various zoom conditions. It should be understood that only two focal conditions (i.e., the first state and the second state) are disclosed in this embodiment, but the present disclosure is not limited thereto. The imaging lens system of this embodiment may further have other focal lengths corresponding to the intermediate range of the first state and the second state in other focal conditions besides the first state and the second state for various lens distances.

[0130] From Table 1B, it can be seen that the second lens group G2 moves along a direction parallel to the optical axis with respect to the first lens group G1 during the focusing process and the zooming process. TABLE 1C Aspherical coefficients Surface # 4 5 7 8 k = 0,000000000E+00 0,000000000E+00 -1,000000000E+00 -1,000000000E+00 A4 = -6,642197955E-03 -1,028326410E-02 -8,040917740E-03 1,537946548E-03 A6 = -9,906090352E-04 -2,646685159E-04 -2,005434721E-03 -1,573343426E-02 A8 = 2,619193620E-03 2,032122139E-03 2,256681534E-03 1,177631092E-02 A10 = -2,555748792E-03 -1,869798787E-03 -1,057229061E-03 -4,756635703E-03 A12 = 1,547758000E-03 1,019470499E-03 2,902880869E-04 1,189209519E-03 A14 = -6,387293212E-04 -3,792293034E-04 -5,597152574E-05 -1,946582269E-04 A16 = 1,853714381E-04 9,981262155E-05 8,598636249E-06 2,133889193E-05 A18 = -3,822214508E-05 -1,873214659E-05 -1,069633964E-06 -1,562958236E-06 A20 = 5,572200433E-06 2,487865286E-06 9,596071678E-08 7,403359835E-08 A22 = -5,617299155E-07 -2,282904281E-07 -5,164085931E-09 -2,072202240E-09 A24 = 3,727012026E-08 1,376291299E-08 1,211974762E-10 2,631026914E-11 A26 = -1,464802454E-09 -4,904384484E-10 - - A28 = 2,584224874E-11 7,827788506E-12 - - Surface # 9 10 13 14 k = 0,000000000E+00 0,000000000E+00 0,000000000E+00 0,000000000E+00 A4 = 8,763291981E-03 1,875102534E-03 -1,229530824E-04 -1,459160828E-02 A6 = -1,920904132E-02 -2,069078994E-03 9,031641513E-04 1,502094967E-02 A8 = 1,325374898E-02 1,106162578E-03 -5,357778958E-04 -5,810692561E-03 A10 = -5,226447324E-03 -3,819872504E-04 2,777744002E-04 1,372939031E-03 A12 = 1,322797006E-03 9,363322204E-05 -9,692055291E-05 -7,017060147E-05 A14 = -2,277367861E-04 -1,730091253E-05 2,245791773E-05 -1,022967826E-04 A16 = 2,761719483E-05 2,457197350E-06 -3,462615141E-06 4,874814583E-05 A18 = -2,400491374E-06 -2,611288588E-07 3,518884181E-07 -1,162935676E-05 A20 = 1,489252628E-07 1,963823686E-08 -2,268540506E-08 1,658006228E-06 A22 = -6,342621138E-09 -9,696460556E-10 8,422496541E-10 -1,421893853E-07 A24 = 1,670619380E-10 2,791724463E-11 -1,373615707E-11 6,773666650E-09 A26 = -2,048653367E-12 -3,537540305E-13 - -1,378638060E-10 Surface # 15 16 17 18 k = 0,000000000E+00 0,000000000E+00 0,000000000E+00 0,000000000E+00 A4 = -4,418766321E-02 -4,607801876E-02 -2,848052728E-02 -1,768530175E-02 A6 = 5,028972892E-02 4,218707443E-02 -2,353315733E-03 -9,171238315E-03 A8 = -2,646872452E-02 -1,960173140E-02 1,118960435E-02 1,355377524E-02 A10 = 9,597249489E-03 6,548937258E-03 -7,523159419E-03 -9,221255307E-03 A12 = -2,669880973E-03 -2,094059111E-03 2,607329472E-03 3,969494346E-03 A14 = 5,762412054E-04 6,317957301E-04 -5,174519179E-04 -1,186559360E-03 A16 = -9,148549383E-05 -1,442103421E-04 5,210828567E-05 2,571683899E-04 A18 = 9,937178524E-06 2,178605274E-05 2,180352227E-07 -4,113043554E-05 A20 = -6,790258570E-07 -2,030863738E-06 -7,695872101E-07 4,829978144E-06 A22 = 2,559091353E-08 1,057580579E-07 9,763123116E-08 -4,048500533E-07 A24 = -3,896001638E-10 -2,353509997E-09 -5,519625657E-09 2,285871917E-08 A26 = - - 1,234975968E-10 -7,759340781E-10 A28 = - - - 1,191473108E-11

[0131] In Table 1C, k represents the conicity coefficient of the aspherical surface profile equation. A4-A28 represent the aspherical coefficients ranging from the 4th to the 28th order. The tables shown below for each embodiment are the corresponding schematic parameter and aberration curves, and the definitions of the tables are the same as in Table 1A to Table 1C of the first embodiment. Therefore, no further explanation is given in this regard. 2. Embodiment

[0132] Fig.4 is a schematic view of an image acquisition unit in each of a first short focal end state and a first long focal end state according to the second embodiment of the present disclosure. Fig. 5 shows, in order from left to right, spherical aberration curves, astigmatic field curves, and a distortion curve of the image pickup unit in the first state with a short focal point end according to the second embodiment. Fig. Fig. 6 shows, in order from left to right, spherical aberration curves, astigmatic field curves, and a distortion curve of the image pickup unit in the first state with a long focal point end according to the second embodiment. The upper part of Fig. 4 shows the imaging lens system in the first state with short focal point end, and the lower part of Fig. 4 shows the imaging lens system in the first state with a long focal point end. In Fig.4, the image acquisition unit 2 includes the imaging system (the reference numeral of which is omitted) of the present disclosure and an image sensor IS. The imaging lens system includes, in order from an object side to an image side along a light path, a reflective element LF, a stop S1, a first lens element E1, an aperture stop ST, a second lens element E2, a third lens element E3, a stop S2, a stop S3, a fourth lens element E4, a fifth lens element E5, a sixth lens element E6, a filter E7, and an image surface IMG. Further, the imaging lens system includes, in order from the object side to the image side along the light path, a first lens group G1 and a second lens group G2.The first lens group G1 includes the first lens element E1, the second lens element E2, and the third lens element E3, and the second lens group G2 includes the fourth lens element E4, the fifth lens element E5, and the sixth lens element E6. The imaging lens system includes six lens elements (E1, E2, E3, E4, E5, and E6) with no additional lens element disposed between each of the adjacent six lens elements.

[0133] The imaging lens system has a first state corresponding to an infinite object distance and a second state corresponding to a finite object distance. The first state refers to a state of the imaging lens system with an imaged object at an infinite distance (the infinite object distance), and the second state refers to a state of the imaging lens system with an imaged object at a finite distance (the finite object distance). When an imaged object at the infinite object distance moves to the finite object distance, the imaging lens system performs a focusing process to change the first state to the second state thereof. Conversely, when an imaged object at the finite object distance moves to the infinite object distance, the imaging lens system also performs the focusing process to change the second state to the first state thereof.Furthermore, during the focusing process of the imaging lens system, the first lens group G1 has no relative movement with respect to a reflective surface of the reflective element LF, the second lens group G2 moves along a direction parallel to an optical axis with respect to the first lens group G1, and the image surface IMG moves along a direction parallel to the optical axis. Note that during the focusing process, no relative movement occurs between any two lens elements of each of the first lens group and the second lens group of the two lens groups.

[0134] The imaging lens system in the first state has a first long focal point state corresponding to a long focal point end and a first short focal point state corresponding to a short focal point end during a zooming operation. When the imaging lens system changes its first long focal point state to the first short focal point state during the zooming operation, the second lens group G2 moves along a direction parallel to the optical axis toward the image side with respect to the first lens group G1. Conversely, when the imaging lens system changes its first short focal point state to the first long focal point state during the zooming operation, the second lens group G2 moves along a direction parallel to the optical axis toward the object side with respect to the first lens group G1. As shown in Fig. 4, the upper part of Fig.4 the imaging lens system in the first state with short focal point end, and the lower part of Fig.4 shows the imaging lens system in the first long focal point state. Similarly, in the second state, the imaging lens system has a second long focal point state corresponding to the long focal point and a second short focal point state corresponding to the short focal point during the focusing process. Furthermore, during the zooming operation of the imaging lens system, the first lens group G1 has no relative movement with respect to the reflective surface of the reflective element LF, the second lens group G2 moves along a direction parallel to the optical axis with respect to the first lens group G1, and the image surface IMG moves along a direction parallel to the optical axis.It should be noted that during the zooming operation, there is no relative movement between any two lens elements of each of the first lens group and the second lens group of the two lens groups.

[0135] The first lens element E1 with negative refractive power has an object-side surface that is convex in a paraxial region thereof and an image-side surface that is concave in a paraxial region thereof. The first lens element E1 is made of plastic material and has the object-side surface and the image-side surface both aspherical. The object-side surface of the first lens element E1 has an inflection point in an off-axis region thereof. The image-side surface of the first lens element E1 has an inflection point in an off-axis region thereof. The object-side surface of the first lens element E1 has a critical point in the off-axis region thereof. The image-side surface of the first lens element E1 has a critical point in the off-axis region thereof.

[0136] The second lens element E2 with negative refractive power has an object-side surface that is concave in a paraxial region thereof and an image-side surface that is concave in a paraxial region thereof. The second lens element E2 is made of plastic material and has both the object-side surface and the image-side surface aspherical. The image-side surface of the second lens element E2 has two inflection points in an off-axis region thereof. The image-side surface of the second lens element E2 has a critical point in the off-axis region thereof.

[0137] The third lens element E3 with positive refractive power has an object-side surface that is convex in a paraxial region thereof and an image-side surface that is convex in a paraxial region thereof. The third lens element E3 is made of glass material and has both the object-side and image-side surfaces aspherical. The object-side surface of the third lens element E3 has two inflection points in an off-axis region thereof.

[0138] The fourth lens element E4 with positive refractive power has an object-side surface that is convex in a paraxial region thereof and an image-side surface that is convex in a paraxial region thereof. The fourth lens element E4 is made of plastic material and has both the object-side surface and the image-side surface aspherical. The object-side surface of the fourth lens element E4 has one inflection point in an off-axis region thereof. The image-side surface of the fourth lens element E4 has three inflection points in an off-axis region thereof. The image-side surface of the fourth lens element E4 has two critical points in the off-axis region thereof.

[0139] The fifth lens element E5 with negative refractive power has an object-side surface that is concave in a paraxial region thereof and an image-side surface that is concave in a paraxial region thereof. The fifth lens element E5 is made of plastic material and has the object-side surface and the image-side surface both aspherical. The object-side surface of the fifth lens element E5 has three inflection points in an off-axis region thereof. The image-side surface of the fifth lens element E5 has one inflection point in an off-axis region thereof. The object-side surface of the fifth lens element E5 has one critical point in the off-axis region thereof. The image-side surface of the fifth lens element E5 has one critical point in the off-axis region thereof.

[0140] The sixth lens element E6 with negative refractive power has an object-side surface that is convex in a paraxial region thereof and an image-side surface that is concave in a paraxial region thereof. The sixth lens element E6 is made of plastic material and has both the object-side surface and the image-side surface aspherical. The object-side surface of the sixth lens element E6 has an inflection point in an off-axis region thereof. The image-side surface of the sixth lens element E6 has two inflection points in an off-axis region thereof. The object-side surface of the sixth lens element E6 has a critical point in the off-axis region thereof.

[0141] The reflective element LF is made of glass material. The reflective element LF is arranged between an imaged object and the first lens group G1 (it can also be assumed that the reflective element LF is arranged on the object side of the first lens element E1). The reflective element LF has no influence on the focal length of the imaging lens system. The reflective element LF is a prism that deflects the optical path. For the sake of simplicity, the reflected light produced by the reflective element LF is Fig.4 is omitted. The reflective element LF has an object-side surface and an image-side surface, both of which are planar, but the present disclosure is not limited thereto. The reflective element LF may have various shapes to achieve different deflection effects on the ray path. For example, the reflective element LF of the second embodiment may be the reflective element LF shown in Fig. 18 to Fig. 20, which deflects the beam path once, whereby the reflecting surface RF1 of the reflecting element LF deflects the first axis OA1 into the second optical axis OA2. The details can be found in the description of Fig. 18 to Fig. 20, which will not be repeated again.

[0142] The filter E7 is made of glass and is located between the sixth lens element E6 and the image surface IMG. It does not affect the focal length of the imaging lens system. The image sensor IS is located on or near the image surface IMG.

[0143] In the imaging system of the image sensing unit 2 according to the second embodiment, a lens element having the maximum central thickness of the imaging lens system is the third lens element E3.

[0144] The detailed optical data of the 2nd embodiment are shown in Table 2A and Table 2B, and the aspherical surface data are shown in Table 2C below. TABLE 2A 2, Embodiment Surface # radius of curvature thickness material index Abbé # Focal length 0 lens Plano D0 1 Reflective element Plano 6,850 Glass 1,847 23,8 - 2 Plano 1,355 3 stop Plano -0,050 4 Lens 1 6,6820 (ASP) 0,626 plastic 1,545 56,1 -55,64 5 5,2944 (ASP) 1,850 6 Ape. Stop Plano 0,668 7 Lens 2 -50,0000 (ASP) 0,931 plastic 1,566 37,4 -14,49 8 9,8792 (ASP) 0,058 9 Lens 3 11,0847 (ASP) 2,500 Glass 1,497 81,6 7,34 10 -5,0321 (ASP) -1,229 11 stop Plano D1 12 stop Plano -0,919 13 Lens 4 6,6384 (ASP) 1,949 plastic 1,534 56,0 7,11 14 -7,9852 (ASP) 0,159 15 Lens 5 -8,6195 (ASP) 0,691 plastic 1,545 56,1 -7,07 16 7,1580 (ASP) 0,634 17 Lens 6 6,6649 (ASP) 0,600 plastic 1,566 37,4 -14,75 18 3,5855 (ASP) D2 19 filter Plano 0,210 Glass 1,517 64,2 - 20 Plano 0,499 21 Picture Plano D3 Note: The reference wavelength is 587.6 nm (d-line). The effective radius of aperture S1 (surface 3) is 2.785 mm. The effective radius of aperture S2 (surface 11) is 3,500 mm. The effective radius of aperture S3 (surface 12) is 3.150 mm. TABLE 2B Optical data for an imaging lens system in the first state with a short focal point end, in the first state with a long focal point end, in the second state with a short focal point end, and in the first state with a long focal point end First state with short focal point end First state with long focal point end fSf [mm] 13,04 fLf [mm] 17,38 FnoSf 2,40 FnoLf 3,20 HFOVSf [deg.] 17,1 HFOVLf [deg.] 12,3 Distance to lens[mm] infinity Distance to lens[mm] infinity D0 [mm] infinity D0 [mm] infinity D1 [mm] 11,062 D1 [mm] 2,448 D2 [mm] 2,021 D2 [mm] 10,640 D3 [mm] 0,000 D3 [mm] 0,200 Second state with short focal point end Second state with long focal point end fSn [mm] 12,99 fLn [mm] 16,81 FnoSn 2,43 FnoLn 3,15 HFOVSn [deg.] 16,9 HFOVLn [deg.] 12,5 Distance to lens[mm] 1008,155 Distance to lens[mm] 1008,155 D0 [mm] 1000,000 D0 [mm] 1000,000 D1 [mm] 11,197 D1 [mm] 3,332 D2 [mm] 1,892 D2 [mm] 9,756 D3 [mm] 0,192 D3 [mm] 0,201

[0145] In Table 2B, the optical data is the same as that of the first embodiment. Furthermore, the imaging lens system of this embodiment can further have other focal lengths corresponding to the intermediate range of the first state and the second state in other moving focusing conditions besides the first state and the second state for different object distances.

[0146] From Table 2B, it can be seen that the second lens group G2 moves in a direction parallel to the optical axis with respect to the first lens group G1 during the focusing process and the zooming process. TABLE 2C Aspherical coefficients Surface # 4 5 7 8 k = 0,000000000E+00 0,000000000E+00 -1,000000000E+00 -1,000000000E+00 A4 = -4,023630502E-03 -8,976609408E-03 -1,623475626E-02 -3,480057384E-02 A6 = -1,172157788E-02 -8,348254979E-03 5,991391793E-03 3,350214251E-02 A8 = 1,672178988E-02 1,290065658E-02 -3,911896783E-03 -2,556156506E-02 A10 = -1,450547533E-02 -1,161886702E-02 1,480883458E-03 1,231658694E-02 A12 = 8,307603655E-03 6,806021879E-03 -2,465934688E-04 -3,884132127E-03 A14 = -3,286275778E-03 -2,733527677E-03 -3,058923743E-05 8,267778940E-04 A16 = 9,194067935E-04 7,731383702E-04 2,496939466E-05 -1,197577580E-04 A18 = -1,834631397E-04 -1,555137956E-04 -5,708338938E-06 1,162866992E-05 A20 = 2,595930896E-05 2,213368953E-05 6,827403181E-07 -7,236257023E-07 A22 = -2,545085646E-06 -2,179044893E-06 -4,309898032E-08 2,605507714E-08 A24 = 1,644328451E-07 1,411681775E-07 1,135114190E-09 -4,124626108E-10 A26 = -6,297352320E-09 -5,414374091E-09 - - A28 = 1,082936425E-10 9,314143228E-11 - - Surface # 9 10 13 14 k = 0,000000000E+00 0,000000000E+00 0,000000000E+00 0,000000000E+00 A4 = -2,459213191E-02 1,681854720E-03 2,831104343E-03 5,650394396E-02 A6 = 3,074494617E-02 -1,480607650E-03 -2,960548804E-04 -2,347681519E-02 A8 = -2,400144307E-02 1,266502950E-03 -1,438810822E-04 4,875526887E-03 A10 = 1,164160210E-02 -6,798010817E-04 1,282298637E-04 -6,129701853E-04 A12 = -3,711644469E-03 2,413300406E-04 -4,412951264E-05 6,732600655E-05 A14 = 8,085954596E-04 -5,829790852E-05 8,629037668E-06 -1,164882482E-05 A16 = -1,224372689E-04 9,719174104E-06 -9,993394919E-07 1,945168086E-06 A18 = 1,286626459E-05 -1,115909379E-06 6,341428861E-08 -1,947032365E-07 A20 = -9,190024025E-07 8,644894630E-08 -1,432222177E-09 1,013076647E-08 A22 = 4,249860857E-08 -4,307807994E-09 -5,044077353E-11 -2,133162535E-10 A24 = -1,145871173E-09 1,244898507E-10 2,509429318E-12 - A26 = 1,365823776E-11 -1,584042904E-12 - - Surface # 15 16 17 18 k = 0,000000000E+00 0,000000000E+00 0,000000000E+00 0,000000000E+00 A4 = 4,821900014E-02 -3,690826443E-02 -6,665417856E-02 -4,571409440E-02 A6 = -1,524115719E-02 3,967252671E-02 5,083430681E-02 3,182082418E-02 A8 = -1,951731922E-03 -3,037411418E-02 -3,192132129E-02 -1,974448347E-02 A10 = 2,424285333E-03 1,571082360E-02 1,568633772E-02 9,329195141E-03 A12 = -7,437762619E-04 -5,596074057E-03 -5,865486547E-03 -3,251049723E-03 A14 = 1,280512656E-04 1,408998996E-03 1,658508064E-03 8,136388877E-04 A16 = -1,413638295E-05 -2,519648787E-04 -3,557432977E-04 -1,432638663E-04 A18 = 1,059541067E-06 3,124178368E-05 5,733275849E-05 1,703439239E-05 A20 = -5,530754797E-08 -2,541912653E-06 -6,740180450E-06 -1,233220988E-06 A22 = 1,912933716E-09 1,215832377E-07 5,432339880E-07 3,555678891E-08 A24 = -3,317526456E-11 -2,584660450E-09 -2,655968651E-08 1,814047040E-09 A26 = - - 5,870490013E-10 -1,859222124E-10 A28 = - - - 4,643561420E-12

[0147] In addition, these parameters listed in Table 2D from Table 2A to Table 2C can be calculated as follows and satisfy the following conditions: TABLE 2D Schematic parameters fSf [mm] 13,04 HFOVSf / HFOVLf 1,39 FnoSf 2,40 10×|TLSf-TLLf| / TLSf 0,09 HFOVSf [deg.] 17,1 (TDSf-TDLf) / TLSf 0,39 TLSf [mm] 22,310 TLSf / ImgH 5,81 TDSf [mm] 19,580 TLLf / lmgH 5,86 fLf [mm] 17,38 fLf / fSf 1,33 FnoLf 3,20 fG1 / fG2 -0,49 HFOVLf [deg.] 12,3 R6 / R7 -0,76 TLLf [mm] 22,515 RG1i / RG2o -0,76 TDLf [mm] 10,966 TG1 / TG2 1,64 fSn [mm] 12,99 10×|FnoSn-FnoSf| 0,30 FnoSn 2,43 10×|FnoLn-FnoLf| 0,50 HFOVSn [deg.] 16,9 10×(TLSn / fSn-TLSf / fSf) 0,22 TLSn [mm] 22,508 10×(TLLn / fLn-TLLf / fLf) 0,44 TDSn [mm] 19,715 f2 / f5 2,05 fLn [mm] 16,81 R6 / CT3 -2,01 FnoLn 3,15 R7 / CT4 3,41 HFOVLn [deg.] 12,5 DImgS [mm] 0,192 TLLn [mm] 22,516 DlmgS / CTmin 0,32 TDLn [mm] 11,850 - -

[0148] In the 2nd embodiment, the equation of the aspherical surface profiles of the aforementioned lens elements is the same as the equation of the 1st embodiment. 3. Embodiment

[0149] Fig. 7 is a schematic view of an image acquisition unit in each of a first short focal end state and a first long focal end state according to the third embodiment of the present disclosure. Fig. 8 shows, in order from left to right, spherical aberration curves, astigmatic field curves, and a distortion curve of the image pickup unit in the first state with a short focal point end according to the third embodiment. Fig. Fig. 9 shows, in order from left to right, spherical aberration curves, astigmatic field curves, and a distortion curve of the image pickup unit in the first state with a long focal point end according to the third embodiment. The upper part of Fig.7 shows the imaging lens system in the first state with short focal point end, and the lower part of Fig. Figure 7 shows the imaging lens system in the first state with a long focal point end. Fig.7, the image acquisition unit 3 includes the imaging lens system (the reference numeral of which is omitted) of the present disclosure and an image sensor IS. The imaging lens system includes, in order from an object side to an image side along a light path, a reflective element LF, a stop S1, a first lens element E1, a second lens element E2, a third lens element E3, an aperture stop ST, a stop S2, a fourth lens element E4, a fifth lens element E5, a sixth lens element E6, a filter E7, and an image surface IMG. Further, the imaging lens system includes, in order from the object side to the image side along the light path, a first lens group G1 and a second lens group G2.The first lens group G1 includes the first lens element E1, the second lens element E2, and the third lens element E3, and the second lens group G2 includes the fourth lens element E4, the fifth lens element E5, and the sixth lens element E6. The imaging lens system includes six lens elements (E1, E2, E3, E4, E5, and E6) with no additional lens element disposed between each of the adjacent six lens elements.

[0150] The imaging lens system has a first state corresponding to an infinite object distance and a second state corresponding to a finite object distance. The first state refers to a state of the imaging lens system with an imaged object at an infinite distance (the infinite object distance), and the second state refers to a state of the imaging lens system with an imaged object at a finite distance (the finite object distance). When an imaged object at the infinite object distance moves to the finite object distance, the imaging lens system performs a focusing process to change the first state to the second state thereof. Conversely, when an imaged object at the finite object distance moves to the infinite object distance, the imaging lens system also performs the focusing process to change the second state to the first state thereof.Furthermore, during the focusing process of the imaging lens system, the first lens group G1 has no relative movement with respect to a reflective surface of the reflective element LF, the second lens group G2 moves along a direction parallel to an optical axis with respect to the first lens group G1, and the image surface IMG moves along a direction parallel to the optical axis. Note that during the zooming operation, there is no relative movement between any two lens elements of each of the first lens group and the second lens group of the two lens groups.

[0151] The imaging lens system in the first state has a first long focal point state corresponding to a long focal point end and a first short focal point state corresponding to a short focal point end during a zooming operation. When the imaging lens system changes from its first long focal point state to the first short focal point state during the zooming operation, the second lens group G2 moves along a direction parallel to the optical axis toward the image side with respect to the first lens group G1. Conversely, when the imaging lens system changes from its first short focal point state to the first long focal point state during the zooming operation, the second lens group G2 moves along a direction parallel to the optical axis toward the object side with respect to the first lens group G1. As shown in Fig. 7, the upper part of Fig.7 the imaging lens system in the first state with short focal point end, and the lower part of Fig.7 shows the imaging lens system in the first long focal point end state. Similarly, in the second state, the imaging lens system has a second long focal point end state corresponding to the long focal point end and a second short focal point end state corresponding to the short focal point end during the zooming operation. Furthermore, during the zooming operation of the imaging lens system, the first lens group G1 has no relative movement with respect to the reflecting surface of the reflecting element LF, the second lens group G2 moves along a direction parallel to the optical axis with respect to the first lens group G1, and the image surface IMG moves along a direction parallel to the optical axis.It should be noted that during the zooming operation, there is no relative movement between any two lens elements of each of the first lens group and the second lens group of the two lens groups.

[0152] The first lens element E1 with positive refractive power has an object-side surface that is concave in a paraxial region thereof and an image-side surface that is convex in a paraxial region thereof. The first lens element E1 is made of plastic material and has the object-side surface and the image-side surface both aspherical. The object-side surface of the first lens element E1 has two inflection points in an off-axis region thereof. The image surface of the first lens element E1 has two inflection points in an off-axis region. The object-side surface of the first lens element E1 has two critical points in the off-axis region. The image surface of the first lens element E1 has two critical points in the off-axis region.

[0153] The second lens element E2 with negative refractive power has an object-side surface that is concave in a paraxial region thereof and an image-side surface that is convex in a paraxial region thereof. The second lens element E2 is made of plastic material and has both the object-side surface and the image-side surface aspherical. The object-side surface of the second lens element E2 has two inflection points in an off-axis region thereof. The image-side surface of the second lens element E2 has two inflection points in an off-axis region thereof. The image-side surface of the second lens element E2 has two critical points in the off-axis region thereof.

[0154] The third lens element E3 with positive refractive power has an object-side surface that is concave in a paraxial region thereof and an image-side surface that is convex in a paraxial region thereof. The third lens element E3 is made of plastic material and has both the object-side surface and the image-side surface aspherical. The object-side surface of the third lens element E3 has an inflection point in an off-axis region thereof. The image-side surface of the third lens element E3 has an inflection point in an off-axis region thereof. The object-side surface of the third lens element E3 has a critical point in the off-axis region thereof.

[0155] The fourth lens element E4 with positive refractive power has an object-side surface that is convex in a paraxial region thereof and an image-side surface that is concave in a paraxial region thereof. The fourth lens element E4 is made of glass material and has the object-side surface and the image-side surface both aspherical. The object-side surface of the fourth lens element E4 has an inflection point in an off-axis region thereof. The image-side surface of the fourth lens element E4 has an inflection point in an off-axis region thereof. The object-side surface of the fourth lens element E4 has a critical point in the off-axis region thereof. The image-side surface of the fourth lens element E4 has a critical point in the off-axis region thereof.

[0156] The fifth lens element E5 with negative refractive power has an object-side surface that is concave in a paraxial region thereof and an image-side surface that is convex in a paraxial region thereof. The fifth lens element E5 is made of plastic and has both an object-side surface and an image-side surface that are aspherical. The object-side surface of the fifth lens element E5 has three inflection points in an off-axis region thereof. The image-side surface of the fifth lens element E5 has three inflection points in an off-axis region thereof.

[0157] The sixth lens element E6 with negative refractive power has an object-side surface that is convex in a paraxial region thereof and an image-side surface that is concave in a paraxial region thereof. The sixth lens element E6 is made of plastic and has both the object-side surface and the image-side surface aspherical. The object-side surface of the sixth lens element E6 has two inflection points in an off-axis region thereof. The image-side surface of the sixth lens element E6 has two inflection points in an off-axis region thereof. The object-side surface of the sixth lens element E6 has a critical point in the off-axis region thereof.

[0158] The reflective element LF is made of glass material. The reflective element LF is arranged between an imaged object and the first lens group G1 (it can also be assumed that the reflective element LF is arranged on an object side of the first lens element E1). The reflective element LF has no influence on the focal length of the imaging lens system. The reflective element LF is a prism that performs a light path deflection function. For the sake of simplicity, the light path deflected by the reflective element LF is Fig. 7 generated beam path deflection effect is omitted.

[0159] The filter E7 is made of glass and is located between the sixth lens element E6 and the image surface IMG. It does not affect the focal length of the imaging lens system. The image sensor IS is located on or near the image surface IMG.

[0160] In the imaging lens system of the image sensing unit 3 according to the third embodiment, a lens element having the maximum central thickness of the imaging lens system is the third lens element E3.

[0161] The detailed optical data of the third embodiment are shown in Table 3A and Table 3B, and the data of the aspherical surface are shown in Table 3C below. TABLE 3A 3, Embodiment Surface # radius of curvature thickness material index Abbé # Focal length 0 lens Plano D0 1 Reflective element Plano 6,850 Glass 1,847 23,8 - 2 Plano 1,345 3 stop Plano -0,010 4 Lens 1 -50,0000 (ASP) 0,752 plastic 1,545 56,1 21,88 5 -9,6802 (ASP) 0,886 6 Lens 2 -7,8231 (ASP) 1,396 plastic 1,614 26,0 -19,65 7 -23,7890 (ASP) 0,035 8 Lens 3 -67,4811 (ASP) 2,800 plastic 1,534 56,0 16,35 9 -7,8476 (ASP) -0,402 10 Ape, stop Plano D1 11 stop Plano -0,720 12 Lens 4 6,4335 (ASP) 1,414 Glass 1,589 61,2 14,19 13 25,6481 (ASP) 0,667 14 Lens 5 -16,6969 (ASP) 0,600 plastic 1,639 23,5 -44,93 15 -40,4966 (ASP) 0,596 16 Lens 6 15,2937 (ASP) 0,639 plastic 1,545 56,1 -10,01 17 3,9612 (ASP) D2 18 filter Plano 0,210 Glass 1,517 64,2 - 19 Plano 0,492 20 Picture Plano D3 Note: The reference wavelength is 587.6 nm (d-line). The effective radius of aperture S1 (surface 3) is 2.960 mm. The effective radius of aperture S2 (surface 11) is 3.090 mm. TABLE 3B Optical data for an imaging lens system in the first state with a short focal point end, in the first state with a long focal point end, in the second state with a short focal point end, and in the second state with a long focal point end First state with short focal point end First state with long focal point end fSf [mm] 15,37 fLf [mm] 20,60 FnoSf 2,60 FnoLf 3,49 HFOVSf [deg.] 14,7 HFOVLf [deg.] 10,4 Object distance [mm] infinity Object distance [mm] infinity D0 [mm] infinity D0 [mm] infinity D1 [mm] 11,419 D1 [mm] 1,422 D2 [mm] 2,025 D2 [mm] 12,022 D3 [mm] 0,000 D3 [mm] 0,205 Second state with short focal point end second state with long focal point end fSn [mm] 15,29 fLn [mm] 20,07 FnoSn 2,63 FnoLn 3,46 HFOVSn [deg.] 14,5 HFOVLn [deg.] 10,4 Object distance [mm] 1508,185 Object distance [mm] 1508,185 D0 [mm] 1500,000 D0 [mm] 1500,000 D1 [mm] 11,614 D1 [mm] 2,199 D2 [mm] 1,836 D2 [mm] 11,251 D3 [mm] 0,198 D3 [mm] 0,208

[0162] In Table 3B, except for the definition of D1 as the axial distance between the aperture stop ST and the stop S2, the other optical data are the same as those of the first embodiment. Furthermore, the imaging lens system of this embodiment can further have other focal lengths corresponding to the intermediate range of the first state and the second state in other moving focusing conditions besides the first state and the second state for different lens distances.

[0163] From Table 3B, it can be seen that the second lens group G2 moves along a direction parallel to the optical axis with respect to the first lens group G1 during the focusing process and the zooming process. TABELLE 3C Asphärische Koeffizienten Oberfläche # 4 5 6 7 k = 0,000000000E+00 0,000000000E+00 -1,000000000E+00 -1,000000000E+00 A4 = 2,256333193E-02 4,621159339E-02 4,216429113E-02 1,773883333E-02 A6 = -1,126636063E-02 -1,599576293E-02 -1,887398842E-02 1,439914377E-02 A8 = 6,983027147E-03 5,733398185E-03 6,955936407E-03 -1,772999676E-02 A10 = -4,219342079E-03 -2,504929072E-03 -2,324115466E-03 8,848434906E-03 A12 = 1,930898103E-03 1,009294883E-03 6,306881298E-04 -2,656133115E-03 A14 = -6,383367931E-04 -3,192490461E-04 -1,305778243E-04 5,190838810E-04 A16 = 1,519029793E-04 7,465260914E-05 1,949252462E-05 -6,751002867E-05 A18 = -2,599740006E-05 -1,264794192E-05 -2,005546249E-06 5,800028010E-06 A20 = 3,170264560E-06 1,529681941E-06 1,351111395E-07 -3,163239448E-07 A22 = -2,687973504E-07 -1,286734148E-07 -5,393161942E-09 9,922418576E-09 A24 = 1,506158561E-08 7,152906229E-09 9,709993446E-11 -1,363064874E-10 A26 = -5,015325541E-10 -2,363101150E-10 - - A28 = 7,516097682E-12 3,514660676E-12 - - Oberfläche # 8 9 12 13 k = 0,000000000E+00 0,000000000E+00 0,000000000E+00 0,000000000E+00 A4 = 7,609101171E-04 -1,040266271E-03 -1,411627974E-04 -7,633310456E-03 A6 = 2,599167769E-02 1,092284035E-03 2,124465618E-04 7,572999330E-03 A8 = -2,359497920E-02 -7,670228257E-04 3,428470937E-04 -2,222301717E-03 A10 = 1,132436050E-02 5,221133949E-04 -1,779628010E-04 1,806248369E-04 A12 = -3,436954191E-03 -2,480704416E-04 2,949063315E-05 5,213109351E-05 A14 = 6,982524331E-04 8,002721597E-05 3,116725609E-06 -1,815266060E-05 A16 = -9,709987027E-05 -1,758847450E-05 -2,249937707E-06 2,580314608E-06 A18 = 9,267376758E-06 2,633778117E-06 4,365143635E-07 -2,003256154E-07 A20 = -5,970066286E-07 -2,643419891E-07 -4,391436918E-08 8,346776749E-09 A22 = 2,482622983E-08 1,700533002E-08 2,329956309E-09 -1,475551294E-10 A24 = -6,028118102E-10 -6,334440128E-10 -5,188702640E-11 - A26 = 6,516497653E-12 1,038483549E-11 - - Oberfläche # 14 15 16 17 k = 0,000000000E+00 0,000000000E+00 0,000000000E+00 0,000000000E+00 A4 = -2,119284229E-02 -2,471760872E-02 -3,590995582E-02 -2,481783617E-02 A6 = 2,392626056E-02 1,936662496E-02 7,626746954E-03 2,974646339E-03 A8 = -1,006181080E-02 -3,765473455E-03 1,038037511E-02 8,254253713E-03 A10 = 2,102507070E-03 -2,223156663E-03 -1,244719141E-02 -9,229998540E-03 A12 = -2,021404054E-04 1,662956785E-03 6,968502939E-03 5,292528232E-03 A14 = -2,738043749E-06 -5,233807489E-04 -2,442912933E-03 -1,954804979E-03 A16 = 2,207778215E-06 9,776290286E-05 5,746508906E-04 4,949785414E-04 A18 = -7,702318438E-08 -1,155195370E-05 -9,231172964E-05 -8,791026084E-05 A20 = -1,661484292E-08 8,522925542E-07 9,994976662E-06 1,096452365E-05 A22 = 1,659299819E-09 -3,600608519E-08 -6,966233529E-07 -9,419896146E-07 A24 = -4,568168156E-11 6,670405170E-10 2,816430989E-08 5,313111303E-08 A26 = - - -5,008419839E-10 -1,771935175E-09 A28 = - - - 2,648906212E-11

[0164] In addition, these parameters listed in Table 3D from Table 3A to Table 3C can be calculated as follows and satisfy the following conditions: TABELLE 3D Schematische Parameter fSf [mm] 15,37 HFOVSf / HFOVLf 1,41 FnoSf 2,60 10×|TLSf-TLLf| / TLSf 0,09 HFOVSf [deg.] 14,7 (TDSf-TDLf) / TLSf 0,44 TLSf [mm] 22,809 TLSf / ImgH 5,94 TDSf [mm] 20,082 TLLf / ImgH 5,99 fLf [mm] 20,60 fLf / fSf 1,34 FnoLf 3,49 fG1 / fG2 -0,51 HFOVLf [deg.] 10,4 R6 / R7 -1,22 TLLf [mm] 23,015 RG1i / RG2o -1,22 TDLf [mm] 10,085 TG1 / TG2 1,50 fSn [mm] 15,29 10×|FnoSn-FnoSf| 0,30 FnoSn 2,63 10×|FnoLn-FnoLf| 0,30 HFOVSn [deg.] 14,5 10×(TLSn / fSn-TLSf / fSf) 0,21 TLSn [mm] 23,013 10×(TLLn / fLn-TLLf / fLf) 0,30 TDSn [mm] 20,277 f2 / f5 0,44 fLn [mm] 20,07 R6 / CT3 -2,80 FnoLn 3,46 R7 / CT4 4,55 HFOVLn [deg.] 10,4 DImgS [mm] 0,198 TLLn [mm] 23,023 DImgS / CTmin 0,33 TDLn [mm] 10,862 - -

[0165] In the third embodiment, the equation of the aspherical surface profiles of the aforementioned lens elements is the same as the equation of the first embodiment. 4. Embodiment

[0166] Fig. 10 is a perspective view of an image acquisition unit according to the fourth embodiment of the present disclosure. In this embodiment, an image acquisition unit 100 is a camera module including a lens unit 101, a drive device 102, an image sensor 103, and an image stabilizer 104. The lens unit 101 includes the imaging lens system disclosed in the first embodiment, a barrel, and a holding member (the reference numerals of which are omitted) for holding the imaging lens system. However, the lens unit 101 may alternatively be provided with the imaging lens system disclosed in other embodiments of the present disclosure, and the present disclosure is not limited thereto.The imaging light is converged in the lens unit 101 of the image acquisition unit 100 to form an image with the drive device 102 used to focus the image onto the image sensor 103, and the formed image is then digitally transmitted to another electronic component for further processing.

[0167] The drive device 102 can have autofocus functionality, and different drive configurations can be achieved through the use of voice coil motors (VCMs), microelectromechanical systems (MEMS), piezoelectric systems, or shape memory alloy materials. The drive device 102 can include a guide element, which can be spherical or rod-shaped. The guide element helps reduce the movement resistance of the movable lens group during the zooming or focusing process. The drive device 102 is advantageous for obtaining a better imaging position of the lens unit 101, so that a clear image of the imaged object can be captured by the lens unit 101 at different object distances.The image sensor 103 (e.g., CCD or CMOS), which may have high light sensitivity and low noise, is arranged on the image surface of the imaging lens system to achieve higher image quality. The image sensor 103 can also be moved in three dimensions relative to a base, so that focus can be achieved by moving the image sensor 103.

[0168] The image stabilizer 104, such as an accelerometer, a gyro sensor, and a Hall-effect sensor, is configured to cooperate with the drive device 102 to provide optical image stabilization (OIS). The drive device 102, which cooperates with the image stabilizer 104, is advantageous for compensating for the pan and tilt movement of the lens unit 101 to reduce motion blur during exposure. In some cases, compensation can be provided by electronic image stabilization (EIS) using image processing software, thereby improving image quality in motion or low-light conditions. 5. Embodiment

[0169] Fig. 11 is a perspective view of an electronic device according to the 5th embodiment of the present disclosure. Fig. 12 is another perspective view of the electronic device in Fig. 11.

[0170] In this embodiment, an electronic device 200 is a smartphone that includes the image capturing unit 100 disclosed in the fourth embodiment, an image capturing unit 100a, an image capturing unit 100b, an image capturing unit 100c, and a display unit 201. As shown in Fig. 11, the image capture unit 100, the image capture unit 100a, and the image capture unit 100b are arranged on the same side of the electronic device 200 and face the same side. As shown in Fig. As shown in Figure 12, the image capture unit 100c and the display unit 201 are arranged on opposite sides of the electronic device 200, so that the image capture unit 100c may be a front-facing camera of the electronic device 200 for taking selfies, but the present disclosure is not limited thereto. Furthermore, each of the image capture units 100a, 100b, and 100c may include the imaging lens system of the present disclosure and have a similar configuration to the image capture unit 100.Specifically, each of the image acquisition units 100a, 100b, and 100c may include a lens unit, a driving device, an image sensor, an image stabilizer, and a reflective element for deflecting the optical path, and each of the lens units may include an optical lens assembly such as the optical lens system of the present disclosure, a tube, and a holding member for holding the optical lens system.

[0171] The image capture unit 100 is a telephoto image capture unit, the image capture unit 100a is a wide-angle image capture unit, the image capture unit 100b is an ultra-wide-angle image capture unit, and the image capture unit 100c is a wide-angle image capture unit. In this embodiment, the image capture units 100, 100a, and 100b have different fields of view, so that the electronic device 200 can have different magnification ratios to meet the requirement of an optical zoom function. In addition, the maximum field of view of the image capture unit 100 ranges from 3 degrees to 35 degrees, and the maximum field of view of the image capture unit 100a ranges from 35 degrees to 70 degrees. Therefore, it is advantageous to have a relatively large zoom ratio of the electronic device 200 to expand its application areas. In addition, the image capture unit 100c, as shown in Fig. 12, have a non-circular opening, and the lens cylinder or lens elements in the image sensing unit 100c may have one or more cut edges at outer positions thereof to correspond with the non-circular opening. Therefore, it is advantageous to further reduce the length of the image sensing unit 100c along a single axis, thereby reducing the overall size of the lens, increasing the area ratio of the display unit 201 with respect to the electronic device 200, reducing the thickness of the electronic device 200, and achieving compactness of the overall module. In this embodiment, the electronic device 200 includes a plurality of image sensing units 100, 100a, 100b, and 100c, but the present disclosure is not limited to the number and arrangement of the image sensing units. 6. Embodiment

[0172] Fig. 13 is a perspective view of an electronic device according to the 6th embodiment of the present disclosure. Fig. 14 is another perspective view of the electronic device in Fig. 13. Fig. 15 is a block diagram of the electronic device in Fig. 13.

[0173] In this embodiment, an electronic device 300 is a smartphone that includes the image capture unit 100 disclosed in the fourth embodiment, an image capture unit 100d, an image capture unit 100e, an image capture unit 100f, an image capture unit 100g, an image capture unit 100h, a flash module 301, a focus assist module 302, an image signal processor 303, a display module 304, and an image software processor 305. The image capture unit 100, the image capture unit 100d, and the image capture unit 100e are arranged on the same side of the electronic device 300. The focus assist module 302 may be a laser distance meter or a time-of-flight (ToF) module, but the present disclosure is not limited thereto.The image capture unit 100f, the image capture unit 100g, the image capture unit 100h, and the display module 304 are arranged on the opposite side of the electronic device 300. The display module 304 may be a user interface, so the image capture units 100f, 100g, and 100h may be front-facing cameras of the electronic device 300 for taking selfies, but the present disclosure is not limited thereto. Furthermore, each of the image capture units 100d, 100e, 100f, 100g, and 100h may include the imaging lens system of the present disclosure and have a similar configuration to the image capture unit 100.Specifically, each of the image acquisition units 100d, 100e, 100f, 100g, and 100h may include a lens unit, a driving device, an image sensor, an image stabilizer, and a reflective element for deflecting the optical path, and each of the lens units may include an optical lens assembly, such as the optical lens system of the present disclosure, a tube, and a holding member for holding the optical lens system.

[0174] Image capture unit 100 is a telephoto image capture unit, image capture unit 100d is a wide-angle image capture unit, image capture unit 100e is an ultra-wide-angle image capture unit, image capture unit 100f is a wide-angle image capture unit, image capture unit 100g is an ultra-wide-angle image capture unit, and image capture unit 100h is a time-of-flight image capture unit. In this embodiment, image capture units 100, 100d, and 100e have different fields of view, so that electronic device 300 can have different magnification ratios to meet the requirement of an optical zoom function. Furthermore, the maximum field of view of image capture unit 100 ranges from 3 degrees to 35 degrees, and the maximum field of view of image capture unit 100d ranges from 35 degrees to 70 degrees.Therefore, it is advantageous if the electronic device 300 has a relatively large zoom factor to expand its application areas. Furthermore, the image capture unit 100 may be a telephoto image capture unit with a light path deflection element configuration, such as a reflective element configuration, so that the total path length of the image capture unit 100 is not limited by the thickness of the electronic device 300. Furthermore, the light path deflection element configuration, such as the reflective element configuration of the image capture unit 100, may be similar to, for example, one of the configurations shown in FIG. Fig. 18 to Fig. 22 shown structures, which with reference to the above descriptions according Fig. 18 to Fig. 22, and the related details will not be repeated. Furthermore, the image acquisition unit 100h can determine depth information of an imaged object. In this embodiment, the electronic device 300 includes a plurality of image acquisition units 100, 100d, 100e, 100f, 100g, and 100h, but the present disclosure is not limited to the number and arrangement of the image acquisition units.

[0175] When a user captures images of an object 306, the light beams converge in the image capture unit 100, the image capture unit 100d, or the image capture unit 100e to create images, and the flash module 301 is activated to provide light assistance. The focus assist module 302 detects the object distance of the imaged object 306 to achieve fast autofocus. The image signal processor 303 is configured to optimize the captured image to improve image quality. The light beam emitted by the focus assist module 302 can be either conventional infrared light or laser light. Additionally, the light beams can converge in the image capture unit 100f, 100g, or 100h to create images.The display module 304 may include a touchscreen, and the user may interact with the display module 304 and the image software processor 305, which has multiple functions for capturing images and performing image processing. Alternatively, the user may capture images using a physical button. The image processed by the image software processor 305 may be displayed on the display module 304. 7. Embodiment

[0176] Fig. 16 is a perspective view of an electronic device according to the 7th embodiment of the present disclosure.

[0177] In this embodiment, an electronic device 400 is a smartphone that includes the image capture unit 100 disclosed in the fourth embodiment, an image capture unit 100i, an image capture unit 100j, an image capture unit 100k, an image capture unit 100m, an image capture unit 100n, an image capture unit 100p, an image capture unit 100q, an image capture unit 100r, a flash module 401, a focus assist module, an image signal processor, a display module, and an image software processor (not shown). The image capture units 100, 100i, 100j, 100k, 100m, 100n, 100p, 100q and 100r are arranged on the same side of the electronic device 400, while the display module is arranged on the opposite side of the electronic device 400.Furthermore, each of the image acquisition units 100i, 100j, 100k, 100m, 100n, 100p, 100q, and 100r may include the imaging lens system of the present disclosure and have a similar configuration to the image acquisition unit 100, the details of which will not be repeated.

[0178] The image capture unit 100 is a telephoto image capture unit, the image capture unit 100i is a telephoto image capture unit, the image capture unit 100j is a wide-angle image capture unit, the image capture unit 100k is a wide-angle image capture unit, the image capture unit 100m is an ultra-wide-angle image capture unit, the image capture unit 100n is an ultra-wide-angle image capture unit, the image capture unit 100p is a telephoto image capture unit, the image capture unit 100q is a telephoto image capture unit, and the image capture unit 100r is a time-of-flight image capture unit. In this embodiment, the image capture units 100, 100i, 100j, 100k, 100m, 100n, 100p, and 100q have different fields of view so that the electronic device 400 can have different magnification ratios to meet the requirements of the optical zoom functionality.Furthermore, the maximum field of view of the image acquisition unit 100 ranges from 3 degrees to 35 degrees, and the maximum field of view of the image acquisition unit 100j ranges from 35 degrees to 70 degrees. Therefore, it is advantageous for the electronic device 400 to have a relatively large zoom factor to expand its application areas. Furthermore, each of the image acquisition units 100 and 100i may be a telephoto image acquisition unit having an optical path deflection element configuration such as a reflective element configuration. Furthermore, the optical path deflection element configuration of each of the image acquisition units 100 and 100i may be, for example, one of the optical path deflection elements shown in FIG. Fig. 18 to Fig. 22 shown structures, which are referred to in the above descriptions Fig. 18 to Fig.22, and the related details will not be repeated. Furthermore, the image capture unit 100r can determine depth information of the imaged object. In this embodiment, the electronic device 400 includes a plurality of image capture units 100, 100i, 100j, 100k, 100m, 100n, 100p, 100q, and 100r, but the present disclosure is not limited to the number and arrangement of the image capture units. When a user captures images of an object, the light beams converge in the image capture unit 100, 100i, 100j, 100k, 100m, 100n, 100p, 100q, or 100r to form images, and the flash module 401 is activated for light assistance. Furthermore, the subsequent processes are performed in a similar manner to the above-mentioned embodiments, and the details thereof will not be repeated.

[0179] The smartphone in this embodiment serves only as an example to demonstrate the image acquisition unit of the present disclosure in an electronic device, and the present disclosure is not limited thereto. The image acquisition unit can optionally be applied to optical systems with a moving focus. Furthermore, the imaging lens system of the image acquisition unit features good aberration correction and high image quality and can be used for 3D image acquisition (three-dimensional image acquisition) applications in products such as digital cameras, mobile devices, digital tablets, smart TVs, network monitoring devices, dashboard cameras, vehicle rearview cameras, multi-camera devices, image recognition systems, motion sensor input devices, wearable devices, and other electronic imaging devices.

Claims

[1] An imaging lens system comprising two lens groups (G1, G2), the two lens groups (G1, G2) being a first lens group (G1) and a second lens group (G2) in order from an object side to an image side along an optical path, each lens element of the two lens groups (G1, G2) having an object-side surface facing the object side and an image-side surface facing the image side, and a total number of lens groups of the imaging lens system is two; wherein the imaging lens system has a first state corresponding to an infinite object distance; wherein the imaging lens system in the first state has a first long focal end state corresponding to a long focal end and a first short focal end state corresponding to a short focal end during a zooming operation, and at least one lens group of the two lens groups (G1, G2) moves along a direction parallel to an optical axis during the zooming operation; wherein at least one of the object-side surface and the image-side surface of at least one lens element of the two lens groups (G1, G2) has at least one inflection point (P) in an off-axis region thereof; wherein the imaging lens system comprises, in order from the object side to the image side along the optical path, a first lens element (E1), a second lens element (E2), a third lens element (E3), and a fourth lens element (E4), and a lens element having a maximum central thickness among the imaging lens system is the third lens element (E3) or the fourth lens element (E4); wherein a focal length of the imaging lens system in the first state with a long focal point end is fLf, a focal length of the imaging lens system in the first state with a short focal point end is fSf, a focal length of the first lens group (G1) is fG1, a focal length of the second lens group (G2) is fG2, a radius of curvature of the image-side surface of the third lens element (E3) is R6, a radius of curvature of the object-side surface of the fourth lens element (E4) is R7, and the following conditions are satisfied: 1.20 <fLf / fSf<2,00; −0.80 <fG1 / fG2<−0,20; und −2.00 <R6 / R7<−0,65. [2] The imaging lens system according to claim 1, wherein half of a maximum field of view of the imaging lens system in the first short focal point end state is HFOVSf, half of a maximum field of view of the imaging lens system in the first long focal point end state is HFOVLf, and the following condition is satisfied: 1.20 <HFOVSf / HFOVLf<2,50. [3] The imaging lens system according to claim 1, wherein an axial distance between the object-side surface of a lens element closest to the object side and the image-side surface of a lens element closest to the image side of the imaging lens system in the first short-focus state is TDSf, an axial distance between the object-side surface of the lens element closest to the object side and the image-side surface of the lens element closest to the image side of the imaging lens system in the first long-focus state is TDLf, an axial distance between the object-side surface of the lens element closest to the object side and an image surface (IMG) of the imaging lens system in the first short-focus state is TLSf, and the following condition is satisfied: 0.20<(TDSf−TDLf) / TLSf<0.

70. [4] The imaging lens system according to claim 1, wherein an axial distance between the object-side surface of a lens element closest to the object side and an image surface (IMG) of the imaging lens system in the first short focal point end state is TLSf, an axial distance between the object-side surface of the lens element closest to the object side and the image surface (IMG) of the imaging lens system in the first long focal point end state is TLLf, and the following condition is satisfied: 0.00≤10×|TLSf−TLLf| / TLSf<1.

00. [5] The imaging lens system according to claim 1, wherein an F-number of the imaging lens system in the first short focal point end state is FnoSf, an F-number of the imaging lens system in the first long focal point end state is FnoLf, and the following conditions are satisfied: 1.50 <FnoSf<4,00; und 1.80 <FnoLf<4,50. [6] The imaging lens system according to claim 1, wherein the imaging lens system comprises six lens elements (E1, E2, E3, E4, E5, E6), and the six lens elements (E1, E2, E3, E4, E5, E6) are, in order from the object side to the image side along the optical path, the first lens element (E1), the second lens element (E2), the third lens element (E3), the fourth lens element (E4), a fifth lens element (E5), and a sixth lens element (E6), the first lens group (G1) comprises the first lens element (E1), the second lens element (E2), and the third lens element (E3), the second lens group (G2) comprises the fourth lens element (E4), the fifth lens element (E5), and the sixth lens element (E6), the second lens group (G2) moves along a direction parallel to the optical axis during the zooming operation,and all lens elements of each of the first lens group (G1) and the second lens group (G2) have no relative movement to each other during the zooming operation., [7] An imaging lens system according to claim 6, wherein the third lens element (E3) has a positive refractive power, the sixth lens element (E6) has a negative refractive power, the image-side surface of the sixth lens element (E6) is concave in a paraxial region thereof, and the image-side surface of the sixth lens element (E6) has at least one inflection point (P) in an off-axial region thereof. [8] An imaging lens system according to claim 6, wherein a focal length of the second lens element (E2) is f2, a focal length of the fifth lens element (E5) is f5, and the following condition is satisfied: 0.00 <f2 / f5<5,00. [9] The imaging lens system according to claim 6, wherein an axial distance between the object-side surface of a lens element closest to the object side and an image surface (IMG) of the imaging lens system in the first short focal point end state is TLSf, an axial distance between the object-side surface of the lens element closest to the object side and the image surface (IMG) of the imaging lens system in the first long focal point end state is TLLf, a maximum image height of the imaging lens system is ImgH, and the following conditions are satisfied: 3.50 <TLSf / ImgH<7,50; und 3.50 <TLLf / ImgH<7,50. [10] The imaging lens system according to claim 1, further comprising a reflective element, wherein the reflective element (LF) has at least one reflective surface (RF1), the reflective element (LF) is arranged between an imaged object and the first lens group (G1), and the first lens group (G1) has no relative movement with respect to the at least one reflective surface (RF1) during the zooming operation. [11] Image acquisition unit (100) comprising: the imaging lens system of claim 1; and an image sensor (103) arranged on an image surface (IMG) of the imaging lens system. [12] Electronic device (200) comprising: a first image capture unit comprising the image capture unit according to claim 11, wherein a maximum field of view of the first image capture unit is in the range of 3 degrees to 35 degrees; and a second image capture unit arranged on the same side of the electronic device (200) as the first image capture unit, wherein a maximum field of view of the second image capture unit is in the range of 35 degrees to 70 degrees. [13] An imaging lens system comprising two lens groups (G1, G2), wherein the two lens groups (G1, G2) are a first lens group (G1) and a second lens group (G2) in the order from an object side to an image side along a light path, each of the lens elements of the two lens groups (G1, G2) has an object-side surface facing the object side and an image-side surface facing the image side, and a total number of lens groups of the imaging lens system is two; wherein the imaging lens system has a first state corresponding to an infinite object distance; wherein the imaging lens system in the first state has a first long focal end state corresponding to a long focal end and a first short focal end state corresponding to a short focal end during a zooming operation, and at least one lens group of the two lens groups (G1, G2) moves along a direction parallel to an optical axis during the zooming operation; wherein at least one of the object-side surface and the image-side surface of at least one lens element of the two lens groups (G1, G2) has at least one inflection point (P) in an off-axis region thereof; wherein a lens element having a maximum central thickness among the imaging lens system is a lens element of the first lens group (G1) closest to the image side or a lens element of the second lens group (G2) closest to the object side; wherein a focal length of the imaging lens system in the first state with a long focal point end is fLf, a focal length of the imaging lens system in the first state with a short focal point end is fSf, a focal length of the first lens group (G1) is fG1, a focal length of the second lens group (G2) is fG2, half of a maximum field of view of the imaging lens system in the first state with a short focal point end is HFOVSf, a radius of curvature of the image-side surface of the lens element of the first lens group (G1) of the imaging lens system that is closest to the image side is RG1i, a radius of curvature of the object-side surface of the lens element of the second lens group (G2) of the imaging lens system that is closest to the object side is RG2o, and the following conditions are satisfied: 1.20 <fLf / fSf<2,00; −0.80 <fG1 / fG2<−0,20; 3.00 degrees <HFOVSf<35,00 Grad; und −2.00 <RG1i / RG2o<−0,65. [14] The imaging lens system according to claim 13, wherein an axial distance between the object-side surface of a lens element closest to the object side and an image surface (IMG) of the imaging lens system in the first short focal point end state is TLSf, an axial distance between the object-side surface of the lens element closest to the object side and the image surface (IMG) of the imaging lens system in the first long focal point end state is TLLf, and the following condition is satisfied: 0.00≤10×|TLSf−TLLf| / TLSf<1.

00. [15] An imaging lens system according to claim 13, wherein the imaging lens system comprises, in the order from the object side to the image side along the optical path, a first lens element (E1), a second lens element (E2), a third lens element (E3), a fourth lens element (E4), and a fifth lens element (E5); wherein an axial distance between the object-side surface of a lens element of the first lens group (G1) closest to the object side and the image-side surface of the lens element of the first lens group (G1) closest to the image side is TG1, an axial distance between the object-side surface of the lens element of the second lens group (G2) closest to the object side and the image-side surface of a lens element of the second lens group (G2) closest to the image side is TG2, a focal length of the second lens element (E2) is f2, a focal length of the fifth lens element (E5) is f5, and the following conditions are met: 0.40 <tG1 / tG2<−4,50; und 0.00 <f2 / f5<5,00. [16] The imaging lens system according to claim 13, wherein the imaging lens system comprises six lens elements (E1, E2, E3, E4, E5, E6), and the six lens elements (E1, E2, E3, E4, E5, E6) are, in the order from the object side to the image side along the optical path, a first lens element (E1), a second lens element (E2), a third lens element (E3), a fourth lens element (E4), a fifth lens element (E5), and a sixth lens element (E6). [17] The imaging lens system according to claim 16, wherein the first lens group (G1) comprises the first lens element (E1), the second lens element (E2) and the third lens element (E3), the second lens group (G2) comprises the fourth lens element (E4), the fifth lens element (E5) and the sixth lens element (E6), the second lens group (G2) moves along a direction parallel to the optical axis during the zooming operation, and all lens elements of each of the first lens group (G1) and the second lens group (G2) have no relative movement to each other during the zooming operation. [18] An imaging lens system according to claim 16, wherein the lens element of the first lens group (G1) closest to the image side has a positive refractive power, the third lens element (E3) has a positive refractive power, the sixth lens element (E6) has a negative refractive power, the image-side surface of the sixth lens element (E6) is concave in a paraxial region thereof, and the image-side surface of the sixth lens element (E6) has at least one inflection point (P) in an off-axial region thereof. [19] The imaging lens system according to claim 16, wherein an axial distance between the object-side surface of a lens element closest to the object side and an image surface (IMG) of the imaging lens system in the first short focal point end state is TLSf, an axial distance between the object-side surface of the lens element closest to the object side and the image surface (IMG) of the imaging lens system in the first long focal point end state is TLLf, a maximum image height of the imaging lens system is ImgH, and the following conditions are satisfied: 3.50 <TLSf / ImgH<7,00; und 3.50 <TLLf / ImgH<7,50. [20] The imaging lens system of claim 13, further comprising a reflective element (LF), wherein the reflective element (LF) has at least one reflective surface (RF1), the reflective element (LF) is arranged between an imaged object and the first lens group (G1), and the first lens group (G1) has no relative movement with respect to the at least one reflective surface (RF1) during the zooming operation. [21] An imaging lens system comprising two lens groups (G1, G2), wherein the two lens groups (G1, G2) are a first lens group (G1) and a second lens group (G2) in the order from an object side to an image side along an optical path, each of the lens elements of the two lens groups (G1, G2) has an object-side surface facing the object side and an image-side surface facing the image side, and a total number of lens groups of the imaging lens system is two; wherein the imaging lens system has a first state corresponding to an infinite object distance and a second state corresponding to a finite object distance; wherein the imaging lens system performs a focusing process to change the first state to the second state thereof during movement of an imaged object from the infinite object distance to the finite object distance; wherein the imaging lens system in the first state has a first long focal end state corresponding to a long focal end and a first short focal end state corresponding to a short focal end during a zooming operation, and at least one lens group of the two lens groups (G1, G2) moves along a direction parallel to an optical axis during the zooming operation; wherein at least one of the object-side surface and the image-side surface of at least one lens element of the two lens groups (G1, G2) has at least one inflection point (P) in an off-axis region thereof; wherein the imaging lens system comprises, in order from the object side to the image side along the optical path, a first lens element (E1), a second lens element (E2), a third lens element (E3), and a fourth lens element (E4), and a lens element having a maximum central thickness among the imaging lens system is the third lens element (E3) or the fourth lens element (E4); wherein a focal length of the imaging lens system in the first state with a long focal point end is fLf, a focal length of the imaging lens system in the first state with a short focal point end is fSf, a focal length of the first lens group (G1) is fG1, a focal length of the second lens group (G2) is fG2, a radius of curvature of the image-side surface of the third lens element (E3) is R6, a radius of curvature of the object-side surface of the fourth lens element (E4) is R7, and the following conditions are satisfied: 1.20 <fLf / fSf<2,00; −0.80 <fG1 / fG2<−0,20; und −2.00 <R6 / R7<−0,65. [22] The imaging lens system according to claim 21, wherein an axial distance between the object-side surface of a lens element closest to the object side and the image-side surface of a lens element closest to the image side of the imaging lens system in the first short-focus state is TDSf, an axial distance between the object-side surface of the lens element closest to the object side and the image-side surface of the lens element closest to the image side of the imaging lens system in the first long-focus state is TDLf, an axial distance between the object-side surface of the lens element closest to the object side and an image surface (IMG) of the imaging lens system in the first short-focus state is TLSf, and the following condition is satisfied: 0.20<(TDSf−TDLf) / TLSf<0.

70. [23] The imaging lens system according to claim 21, wherein an axial distance between the object-side surface of a lens element closest to the object side and an image surface (IMG) of the imaging lens system in the first short focal point end state is TLSf, an axial distance between the object-side surface of the lens element closest to the object side and the image surface (IMG) of the imaging lens system in the first long focal point end state is TLLf, and the following condition is satisfied: 0.00≤10×|TLSf−TLLf| / TLSf<1.

00. [24] The imaging lens system according to claim 21, wherein the imaging lens system in the second state has a second long focal end state corresponding to the long focal end and a second short focal end state corresponding to the short focal end during the zooming operation, an F-number of the imaging lens system in the first short focal end state is FnoSf, an F-number of the imaging lens system in the second short focal end state is FnoSn, an F-number of the imaging lens system in the first long focal end state is FnoLf, an F-number of the imaging lens system in the second long focal end state is FnoLn, and the following conditions are satisfied: 0.01<10×|FnoSn−FnoSf|<1.00; and 0.01<10×|FnoLn−FnoLf|<1.

00. [25] The imaging lens system according to claim 21, wherein the imaging lens system in the second state has a second long focal end state corresponding to the long focal end and a second short focal end state corresponding to the short focal end during the focusing process, an axial distance between the object-side surface of a lens element closest to the object side and an image surface (IMG) of the imaging lens system in the first short focal end state is TLSf, an axial distance between the object-side surface of the lens element closest to the object side and the image surface (IMG) of the imaging lens system in the second short focal end state is TLSn, an axial distance between the object-side surface of the lens element closest to the object side and the image surface (IMG) of the imaging lens system in the first long focal end state is TLLf,an axial distance between the object-side surface of the lens element closest to the object side and the image surface (IMG) of the imaging lens system in the second state with a long focal point end is TLLn, the focal length of the imaging lens system in the first state with a short focal point end is fSf, a focal length of the imaging lens system in the second state with a short focal point end is fSn, the focal length of the imaging lens system in the first state with a long focal point end is fLf, a focal length of the imaging lens system in the second state with a long focal point end is fLn, and the following conditions are met: 0.10<10×(TLSn / fSn−TLSf / fSf)<0.80; and 0.10<10×(TLLn / fLn−TLLf / fLf)<0.

80. [26] The imaging lens system according to claim 21, wherein the imaging lens system comprises six lens elements (E1, E2, E3, E4, E5, E6), the six lens elements (E1, E2, E3, E4, E5, E6) being, in the order from the object side to the image side along the optical path, the first lens element (E1), the second lens element (E2), the third lens element (E3), the fourth lens element (E4), a fifth lens element (E5), and a sixth lens element (E6), the first lens group (G1) comprises the first lens element (E1), the second lens element (E2), and the third lens element (E3), and the second lens group (G2) comprises the fourth lens element (E4), the fifth lens element (E5), and the sixth lens element (E6). [27] The imaging lens system according to claim 26, wherein the radius of curvature of the image-side surface of the third lens element (E3) is R6, the radius of curvature of the object-side surface of the fourth lens element (E4) is R7, a central thickness of the third lens element (E3) is CT3, a central thickness of the fourth lens element (E4) is CT4, and the following conditions are satisfied: −10.00 <R6 / CT3<0,00; und 0.00 <R7 / CT4<10,00. [28] The imaging lens system according to claim 26, wherein the imaging lens system in the second state has a second long focal point end state corresponding to the long focal point end and a second short focal point end state corresponding to the short focal point end during the zooming process, an image surface (IMG) of the imaging lens system moves along a direction parallel to the optical axis during the zooming process or the focusing process, a displacement of the image surface (IMG) during the change of the imaging lens system from the first short focal point end state to the second short focal point end state is DImgS, and the following condition is satisfied: 0.050 mm <DImgS<0,800 mm. [29] The imaging lens system according to claim 26, wherein the imaging lens system in the second state has a second long focal point state corresponding to the long focal point and a second short focal point state corresponding to the short focal point during the zooming process, an image surface (IMG) of the imaging lens system moves along a direction parallel to the optical axis during the zooming process or the focusing process, a displacement of the image surface (IMG) during the change of the imaging lens system from the first short focal point state to the second short focal point state is DImgS, a minimum value among the central thicknesses of all the lens elements of the imaging lens system is CTmin, and the following condition is satisfied: 0.10 <DImgS / CTmin<1,50. [30] The imaging lens system according to claim 21, wherein the focal length of the imaging lens system at the first long focal point end state is fLf, the focal length of the imaging lens system at the first short focal point end state is fSf, the focal length of the first lens group (G1) is fG1, the focal length of the second lens group (G2) is fG2, the radius of curvature of the image-side surface of the third lens element (E3) is R6, the radius of curvature of the object-side surface of the fourth lens element (E4) is R7, a radius of curvature of the image-side surface of a lens element of the first lens group (G1) of the imaging lens system that is closest to the image side is RG1i, a radius of curvature of the object-side surface of a lens element of the second lens group (G2) of the imaging lens system that is closest to the object side is RG2o,half of a maximum field of view of the imaging lens system in the first state with short focal point end HFOVSf, and the following conditions are met:, 1.33≤fLf / fSf≤1.34; −0.51≤fG1 / fG2≤-0.47; −1.22≤R6 / R7≤-0.76; −1.22≤RG1i / RG2o≤-0.76; and 14.67 degrees≤HFOVSf≤17.09 degrees.

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